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href='../../../core/index.html'><img src='https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png' alt='logo' width='100'></a></nav><div class="theme-picker"><button id="theme-picker" aria-label="Pick another theme!"><img src="../../../brush.svg" width="18" alt="Pick another theme!"></button><div id="theme-choices"></div></div><script src="../../../theme.js"></script><nav class="sub"><form class="search-form js-only"><div class="search-container"><input class="search-input" name="search" autocomplete="off" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><a id="settings-menu" href="../../../settings.html"><img src="../../../wheel.svg" width="18" alt="Change settings"></a></div></form></nav><section id="main" class="content"><pre class="line-numbers"><span id="1"> 1</span> <span id="2"> 2</span> <span id="3"> 3</span> <span id="4"> 4</span> <span id="5"> 5</span> <span id="6"> 6</span> <span id="7"> 7</span> <span id="8"> 8</span> <span id="9"> 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id="719"> 719</span> <span id="720"> 720</span> <span id="721"> 721</span> <span id="722"> 722</span> <span id="723"> 723</span> <span id="724"> 724</span> <span id="725"> 725</span> <span id="726"> 726</span> <span id="727"> 727</span> <span id="728"> 728</span> <span id="729"> 729</span> <span id="730"> 730</span> <span id="731"> 731</span> <span id="732"> 732</span> <span id="733"> 733</span> <span id="734"> 734</span> <span id="735"> 735</span> <span id="736"> 736</span> <span id="737"> 737</span> <span id="738"> 738</span> <span id="739"> 739</span> <span id="740"> 740</span> <span id="741"> 741</span> <span id="742"> 742</span> <span id="743"> 743</span> <span id="744"> 744</span> <span id="745"> 745</span> <span id="746"> 746</span> <span id="747"> 747</span> <span id="748"> 748</span> <span id="749"> 749</span> <span id="750"> 750</span> <span id="751"> 751</span> <span id="752"> 752</span> <span id="753"> 753</span> <span id="754"> 754</span> <span id="755"> 755</span> <span id="756"> 756</span> <span id="757"> 757</span> <span id="758"> 758</span> <span id="759"> 759</span> <span id="760"> 760</span> <span id="761"> 761</span> <span id="762"> 762</span> <span id="763"> 763</span> <span id="764"> 764</span> <span id="765"> 765</span> <span id="766"> 766</span> <span id="767"> 767</span> <span id="768"> 768</span> <span id="769"> 769</span> <span id="770"> 770</span> <span id="771"> 771</span> <span id="772"> 772</span> <span id="773"> 773</span> <span id="774"> 774</span> <span id="775"> 775</span> <span id="776"> 776</span> <span id="777"> 777</span> <span id="778"> 778</span> <span id="779"> 779</span> <span id="780"> 780</span> <span id="781"> 781</span> <span id="782"> 782</span> <span id="783"> 783</span> <span id="784"> 784</span> <span id="785"> 785</span> <span id="786"> 786</span> <span id="787"> 787</span> <span id="788"> 788</span> <span id="789"> 789</span> <span id="790"> 790</span> <span id="791"> 791</span> <span id="792"> 792</span> <span id="793"> 793</span> <span id="794"> 794</span> <span id="795"> 795</span> <span id="796"> 796</span> <span id="797"> 797</span> <span id="798"> 798</span> <span id="799"> 799</span> <span id="800"> 800</span> <span id="801"> 801</span> <span id="802"> 802</span> <span id="803"> 803</span> <span id="804"> 804</span> <span id="805"> 805</span> <span id="806"> 806</span> <span id="807"> 807</span> <span id="808"> 808</span> <span id="809"> 809</span> <span id="810"> 810</span> <span id="811"> 811</span> <span id="812"> 812</span> <span id="813"> 813</span> <span id="814"> 814</span> <span id="815"> 815</span> <span id="816"> 816</span> <span id="817"> 817</span> <span id="818"> 818</span> <span id="819"> 819</span> <span id="820"> 820</span> <span id="821"> 821</span> <span id="822"> 822</span> <span id="823"> 823</span> <span id="824"> 824</span> <span id="825"> 825</span> <span id="826"> 826</span> <span id="827"> 827</span> <span id="828"> 828</span> <span id="829"> 829</span> <span id="830"> 830</span> <span id="831"> 831</span> <span id="832"> 832</span> <span id="833"> 833</span> <span id="834"> 834</span> <span id="835"> 835</span> <span id="836"> 836</span> <span id="837"> 837</span> <span id="838"> 838</span> <span id="839"> 839</span> <span id="840"> 840</span> <span id="841"> 841</span> <span id="842"> 842</span> <span id="843"> 843</span> <span id="844"> 844</span> <span id="845"> 845</span> <span id="846"> 846</span> <span id="847"> 847</span> <span id="848"> 848</span> <span id="849"> 849</span> <span id="850"> 850</span> <span id="851"> 851</span> <span id="852"> 852</span> <span id="853"> 853</span> <span id="854"> 854</span> <span id="855"> 855</span> <span id="856"> 856</span> <span id="857"> 857</span> <span id="858"> 858</span> <span id="859"> 859</span> <span id="860"> 860</span> <span id="861"> 861</span> <span id="862"> 862</span> <span id="863"> 863</span> <span id="864"> 864</span> <span id="865"> 865</span> <span id="866"> 866</span> <span id="867"> 867</span> <span id="868"> 868</span> <span id="869"> 869</span> <span id="870"> 870</span> <span id="871"> 871</span> <span id="872"> 872</span> <span id="873"> 873</span> <span id="874"> 874</span> <span id="875"> 875</span> <span id="876"> 876</span> <span id="877"> 877</span> <span id="878"> 878</span> <span id="879"> 879</span> <span id="880"> 880</span> <span id="881"> 881</span> <span id="882"> 882</span> <span id="883"> 883</span> <span id="884"> 884</span> <span id="885"> 885</span> <span id="886"> 886</span> <span id="887"> 887</span> <span id="888"> 888</span> <span id="889"> 889</span> <span id="890"> 890</span> <span id="891"> 891</span> <span id="892"> 892</span> <span id="893"> 893</span> <span id="894"> 894</span> <span id="895"> 895</span> <span id="896"> 896</span> <span id="897"> 897</span> <span id="898"> 898</span> <span id="899"> 899</span> <span id="900"> 900</span> <span id="901"> 901</span> <span id="902"> 902</span> <span id="903"> 903</span> <span id="904"> 904</span> <span id="905"> 905</span> <span id="906"> 906</span> <span id="907"> 907</span> <span id="908"> 908</span> <span id="909"> 909</span> <span id="910"> 910</span> <span id="911"> 911</span> <span id="912"> 912</span> <span id="913"> 913</span> <span id="914"> 914</span> <span id="915"> 915</span> <span id="916"> 916</span> <span id="917"> 917</span> <span id="918"> 918</span> <span id="919"> 919</span> <span id="920"> 920</span> <span id="921"> 921</span> <span id="922"> 922</span> <span id="923"> 923</span> <span id="924"> 924</span> <span id="925"> 925</span> <span id="926"> 926</span> <span id="927"> 927</span> <span id="928"> 928</span> <span id="929"> 929</span> <span id="930"> 930</span> <span id="931"> 931</span> <span id="932"> 932</span> <span id="933"> 933</span> <span id="934"> 934</span> <span id="935"> 935</span> <span id="936"> 936</span> <span id="937"> 937</span> <span id="938"> 938</span> <span id="939"> 939</span> <span id="940"> 940</span> <span id="941"> 941</span> <span id="942"> 942</span> <span id="943"> 943</span> <span id="944"> 944</span> <span id="945"> 945</span> <span id="946"> 946</span> <span id="947"> 947</span> <span id="948"> 948</span> <span id="949"> 949</span> <span id="950"> 950</span> <span id="951"> 951</span> <span id="952"> 952</span> <span id="953"> 953</span> <span id="954"> 954</span> <span id="955"> 955</span> <span id="956"> 956</span> <span id="957"> 957</span> <span id="958"> 958</span> <span id="959"> 959</span> <span id="960"> 960</span> <span id="961"> 961</span> <span id="962"> 962</span> <span id="963"> 963</span> <span id="964"> 964</span> <span id="965"> 965</span> <span id="966"> 966</span> <span id="967"> 967</span> <span id="968"> 968</span> <span id="969"> 969</span> <span id="970"> 970</span> <span id="971"> 971</span> <span id="972"> 972</span> <span id="973"> 973</span> <span id="974"> 974</span> <span id="975"> 975</span> <span id="976"> 976</span> <span id="977"> 977</span> <span id="978"> 978</span> <span id="979"> 979</span> <span id="980"> 980</span> <span id="981"> 981</span> <span id="982"> 982</span> <span id="983"> 983</span> <span id="984"> 984</span> <span id="985"> 985</span> <span id="986"> 986</span> <span id="987"> 987</span> <span id="988"> 988</span> <span id="989"> 989</span> <span id="990"> 990</span> <span id="991"> 991</span> <span id="992"> 992</span> <span id="993"> 993</span> <span id="994"> 994</span> <span id="995"> 995</span> <span id="996"> 996</span> <span id="997"> 997</span> <span id="998"> 998</span> <span id="999"> 999</span> <span id="1000">1000</span> <span id="1001">1001</span> <span id="1002">1002</span> <span id="1003">1003</span> <span id="1004">1004</span> <span id="1005">1005</span> <span id="1006">1006</span> <span id="1007">1007</span> <span id="1008">1008</span> <span id="1009">1009</span> <span id="1010">1010</span> <span id="1011">1011</span> <span id="1012">1012</span> <span id="1013">1013</span> <span id="1014">1014</span> <span id="1015">1015</span> <span id="1016">1016</span> <span id="1017">1017</span> <span id="1018">1018</span> <span id="1019">1019</span> <span id="1020">1020</span> <span id="1021">1021</span> <span id="1022">1022</span> <span id="1023">1023</span> <span id="1024">1024</span> <span id="1025">1025</span> <span id="1026">1026</span> <span id="1027">1027</span> <span id="1028">1028</span> <span id="1029">1029</span> <span id="1030">1030</span> <span id="1031">1031</span> <span id="1032">1032</span> <span id="1033">1033</span> <span id="1034">1034</span> <span id="1035">1035</span> <span id="1036">1036</span> <span id="1037">1037</span> <span id="1038">1038</span> <span id="1039">1039</span> <span id="1040">1040</span> <span id="1041">1041</span> <span id="1042">1042</span> <span id="1043">1043</span> <span id="1044">1044</span> <span id="1045">1045</span> <span id="1046">1046</span> <span id="1047">1047</span> <span id="1048">1048</span> <span id="1049">1049</span> <span id="1050">1050</span> <span id="1051">1051</span> <span id="1052">1052</span> <span id="1053">1053</span> <span id="1054">1054</span> <span id="1055">1055</span> <span id="1056">1056</span> <span id="1057">1057</span> <span id="1058">1058</span> <span id="1059">1059</span> <span id="1060">1060</span> <span id="1061">1061</span> <span id="1062">1062</span> <span id="1063">1063</span> <span id="1064">1064</span> <span id="1065">1065</span> <span id="1066">1066</span> <span id="1067">1067</span> <span id="1068">1068</span> <span id="1069">1069</span> <span id="1070">1070</span> <span id="1071">1071</span> <span id="1072">1072</span> <span id="1073">1073</span> <span id="1074">1074</span> <span id="1075">1075</span> <span id="1076">1076</span> <span id="1077">1077</span> <span id="1078">1078</span> <span id="1079">1079</span> <span id="1080">1080</span> <span id="1081">1081</span> <span id="1082">1082</span> <span id="1083">1083</span> <span id="1084">1084</span> <span id="1085">1085</span> <span id="1086">1086</span> <span id="1087">1087</span> <span id="1088">1088</span> <span id="1089">1089</span> <span id="1090">1090</span> <span id="1091">1091</span> <span id="1092">1092</span> <span id="1093">1093</span> <span id="1094">1094</span> <span id="1095">1095</span> <span id="1096">1096</span> <span id="1097">1097</span> <span id="1098">1098</span> <span id="1099">1099</span> <span id="1100">1100</span> <span id="1101">1101</span> <span id="1102">1102</span> <span id="1103">1103</span> <span id="1104">1104</span> <span id="1105">1105</span> <span id="1106">1106</span> <span id="1107">1107</span> <span id="1108">1108</span> <span id="1109">1109</span> <span id="1110">1110</span> <span id="1111">1111</span> <span id="1112">1112</span> <span id="1113">1113</span> <span id="1114">1114</span> <span id="1115">1115</span> <span id="1116">1116</span> <span id="1117">1117</span> <span id="1118">1118</span> <span id="1119">1119</span> <span id="1120">1120</span> <span id="1121">1121</span> <span id="1122">1122</span> <span id="1123">1123</span> <span id="1124">1124</span> <span id="1125">1125</span> <span id="1126">1126</span> <span id="1127">1127</span> <span id="1128">1128</span> <span id="1129">1129</span> <span id="1130">1130</span> <span id="1131">1131</span> <span id="1132">1132</span> <span id="1133">1133</span> <span id="1134">1134</span> <span id="1135">1135</span> <span id="1136">1136</span> <span id="1137">1137</span> <span id="1138">1138</span> <span id="1139">1139</span> <span id="1140">1140</span> <span id="1141">1141</span> <span id="1142">1142</span> <span id="1143">1143</span> <span id="1144">1144</span> <span id="1145">1145</span> <span id="1146">1146</span> <span id="1147">1147</span> <span id="1148">1148</span> <span id="1149">1149</span> <span id="1150">1150</span> <span id="1151">1151</span> <span id="1152">1152</span> <span id="1153">1153</span> <span id="1154">1154</span> <span id="1155">1155</span> <span id="1156">1156</span> <span id="1157">1157</span> <span id="1158">1158</span> <span id="1159">1159</span> <span id="1160">1160</span> <span id="1161">1161</span> <span id="1162">1162</span> <span id="1163">1163</span> <span id="1164">1164</span> <span id="1165">1165</span> <span id="1166">1166</span> <span id="1167">1167</span> <span id="1168">1168</span> <span id="1169">1169</span> <span id="1170">1170</span> <span id="1171">1171</span> <span id="1172">1172</span> <span id="1173">1173</span> <span id="1174">1174</span> <span id="1175">1175</span> <span id="1176">1176</span> <span id="1177">1177</span> <span id="1178">1178</span> <span id="1179">1179</span> <span id="1180">1180</span> <span id="1181">1181</span> <span id="1182">1182</span> <span id="1183">1183</span> <span id="1184">1184</span> <span id="1185">1185</span> <span id="1186">1186</span> <span id="1187">1187</span> <span id="1188">1188</span> <span id="1189">1189</span> <span id="1190">1190</span> <span id="1191">1191</span> <span id="1192">1192</span> <span id="1193">1193</span> <span id="1194">1194</span> <span id="1195">1195</span> <span id="1196">1196</span> <span id="1197">1197</span> <span id="1198">1198</span> <span id="1199">1199</span> <span id="1200">1200</span> <span id="1201">1201</span> <span id="1202">1202</span> <span id="1203">1203</span> <span id="1204">1204</span> <span id="1205">1205</span> <span id="1206">1206</span> <span id="1207">1207</span> <span id="1208">1208</span> <span id="1209">1209</span> <span id="1210">1210</span> <span id="1211">1211</span> <span id="1212">1212</span> <span id="1213">1213</span> <span id="1214">1214</span> <span id="1215">1215</span> <span id="1216">1216</span> <span id="1217">1217</span> <span id="1218">1218</span> <span id="1219">1219</span> <span id="1220">1220</span> <span id="1221">1221</span> <span id="1222">1222</span> <span id="1223">1223</span> <span id="1224">1224</span> <span id="1225">1225</span> <span id="1226">1226</span> <span id="1227">1227</span> <span id="1228">1228</span> <span id="1229">1229</span> <span id="1230">1230</span> <span id="1231">1231</span> <span id="1232">1232</span> <span id="1233">1233</span> <span id="1234">1234</span> <span id="1235">1235</span> <span id="1236">1236</span> <span id="1237">1237</span> <span id="1238">1238</span> <span id="1239">1239</span> <span id="1240">1240</span> <span id="1241">1241</span> <span id="1242">1242</span> <span id="1243">1243</span> <span id="1244">1244</span> <span id="1245">1245</span> <span id="1246">1246</span> <span id="1247">1247</span> <span id="1248">1248</span> <span id="1249">1249</span> <span id="1250">1250</span> <span id="1251">1251</span> <span id="1252">1252</span> <span id="1253">1253</span> <span id="1254">1254</span> <span id="1255">1255</span> <span id="1256">1256</span> <span id="1257">1257</span> <span id="1258">1258</span> <span id="1259">1259</span> <span id="1260">1260</span> <span id="1261">1261</span> <span id="1262">1262</span> <span id="1263">1263</span> <span id="1264">1264</span> <span id="1265">1265</span> <span id="1266">1266</span> <span id="1267">1267</span> <span id="1268">1268</span> <span id="1269">1269</span> <span id="1270">1270</span> <span id="1271">1271</span> <span id="1272">1272</span> <span id="1273">1273</span> <span id="1274">1274</span> <span id="1275">1275</span> <span id="1276">1276</span> <span id="1277">1277</span> <span id="1278">1278</span> <span id="1279">1279</span> <span id="1280">1280</span> <span id="1281">1281</span> <span id="1282">1282</span> <span id="1283">1283</span> <span id="1284">1284</span> <span id="1285">1285</span> <span id="1286">1286</span> <span id="1287">1287</span> <span id="1288">1288</span> <span id="1289">1289</span> <span id="1290">1290</span> <span id="1291">1291</span> <span id="1292">1292</span> <span id="1293">1293</span> <span id="1294">1294</span> <span id="1295">1295</span> <span id="1296">1296</span> <span id="1297">1297</span> <span id="1298">1298</span> <span id="1299">1299</span> <span id="1300">1300</span> <span id="1301">1301</span> <span id="1302">1302</span> <span id="1303">1303</span> <span id="1304">1304</span> <span id="1305">1305</span> <span id="1306">1306</span> <span id="1307">1307</span> <span id="1308">1308</span> <span id="1309">1309</span> <span id="1310">1310</span> <span id="1311">1311</span> <span id="1312">1312</span> <span id="1313">1313</span> <span id="1314">1314</span> <span id="1315">1315</span> <span id="1316">1316</span> <span id="1317">1317</span> <span id="1318">1318</span> <span id="1319">1319</span> <span id="1320">1320</span> <span id="1321">1321</span> <span id="1322">1322</span> <span id="1323">1323</span> <span id="1324">1324</span> <span id="1325">1325</span> <span id="1326">1326</span> <span id="1327">1327</span> <span id="1328">1328</span> <span id="1329">1329</span> <span id="1330">1330</span> <span id="1331">1331</span> <span id="1332">1332</span> <span id="1333">1333</span> <span id="1334">1334</span> <span id="1335">1335</span> <span id="1336">1336</span> <span id="1337">1337</span> <span id="1338">1338</span> <span id="1339">1339</span> <span id="1340">1340</span> <span id="1341">1341</span> <span id="1342">1342</span> <span id="1343">1343</span> <span id="1344">1344</span> <span id="1345">1345</span> <span id="1346">1346</span> <span id="1347">1347</span> <span id="1348">1348</span> <span id="1349">1349</span> <span id="1350">1350</span> <span id="1351">1351</span> <span id="1352">1352</span> <span id="1353">1353</span> <span id="1354">1354</span> <span id="1355">1355</span> <span id="1356">1356</span> <span id="1357">1357</span> <span id="1358">1358</span> <span id="1359">1359</span> <span id="1360">1360</span> <span id="1361">1361</span> <span id="1362">1362</span> <span id="1363">1363</span> <span id="1364">1364</span> <span id="1365">1365</span> <span id="1366">1366</span> <span id="1367">1367</span> <span id="1368">1368</span> <span id="1369">1369</span> <span id="1370">1370</span> <span id="1371">1371</span> <span id="1372">1372</span> <span id="1373">1373</span> <span id="1374">1374</span> <span id="1375">1375</span> <span id="1376">1376</span> <span id="1377">1377</span> <span id="1378">1378</span> <span id="1379">1379</span> <span id="1380">1380</span> <span id="1381">1381</span> <span id="1382">1382</span> <span id="1383">1383</span> <span id="1384">1384</span> <span id="1385">1385</span> <span id="1386">1386</span> <span id="1387">1387</span> <span id="1388">1388</span> <span id="1389">1389</span> <span id="1390">1390</span> <span id="1391">1391</span> <span id="1392">1392</span> <span id="1393">1393</span> <span id="1394">1394</span> <span id="1395">1395</span> <span id="1396">1396</span> <span id="1397">1397</span> <span id="1398">1398</span> <span id="1399">1399</span> <span id="1400">1400</span> <span id="1401">1401</span> <span id="1402">1402</span> <span id="1403">1403</span> <span id="1404">1404</span> <span id="1405">1405</span> <span id="1406">1406</span> <span id="1407">1407</span> <span id="1408">1408</span> <span id="1409">1409</span> <span id="1410">1410</span> <span id="1411">1411</span> <span id="1412">1412</span> <span id="1413">1413</span> </pre><pre class="rust "> <span class="comment">// Copyright 2015 The Rust Project Developers. See the COPYRIGHT</span> <span class="comment">// file at the top-level directory of this distribution and at</span> <span class="comment">// http://rust-lang.org/COPYRIGHT.</span> <span class="comment">//</span> <span class="comment">// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or</span> <span class="comment">// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license</span> <span class="comment">// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your</span> <span class="comment">// option. This file may not be copied, modified, or distributed</span> <span class="comment">// except according to those terms.</span> <span class="doccomment">//! The string Pattern API.</span> <span class="doccomment">//!</span> <span class="doccomment">//! For more details, see the traits `Pattern`, `Searcher`,</span> <span class="doccomment">//! `ReverseSearcher` and `DoubleEndedSearcher`.</span> <span class="attribute">#![<span class="ident">unstable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"pattern"</span>, <span class="ident">reason</span> <span class="op">=</span> <span class="string">"API not fully fleshed out and ready to be stabilized"</span>, <span class="ident">issue</span> <span class="op">=</span> <span class="string">"27721"</span>)]</span> <span class="kw">use</span> <span class="ident">cmp</span>; <span class="kw">use</span> <span class="ident">fmt</span>; <span class="kw">use</span> <span class="ident">slice</span>::<span class="ident">memchr</span>; <span class="kw">use</span> <span class="ident">usize</span>; <span class="comment">// Pattern</span> <span class="doccomment">/// A string pattern.</span> <span class="doccomment">///</span> <span class="doccomment">/// A `Pattern<'a>` expresses that the implementing type</span> <span class="doccomment">/// can be used as a string pattern for searching in a `&'a str`.</span> <span class="doccomment">///</span> <span class="doccomment">/// For example, both `'a'` and `"aa"` are patterns that</span> <span class="doccomment">/// would match at index `1` in the string `"baaaab"`.</span> <span class="doccomment">///</span> <span class="doccomment">/// The trait itself acts as a builder for an associated</span> <span class="doccomment">/// `Searcher` type, which does the actual work of finding</span> <span class="doccomment">/// occurrences of the pattern in a string.</span> <span class="kw">pub</span> <span class="kw">trait</span> <span class="ident">Pattern</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span>: <span class="ident">Sized</span> { <span class="doccomment">/// Associated searcher for this pattern</span> <span class="kw">type</span> <span class="ident">Searcher</span>: <span class="ident">Searcher</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span>; <span class="doccomment">/// Constructs the associated searcher from</span> <span class="doccomment">/// `self` and the `haystack` to search in.</span> <span class="kw">fn</span> <span class="ident">into_searcher</span>(<span class="self">self</span>, <span class="ident">haystack</span>: <span class="kw-2">&</span><span class="lifetime">'a</span> <span class="ident">str</span>) <span class="op">-></span> <span class="self">Self</span>::<span class="ident">Searcher</span>; <span class="doccomment">/// Checks whether the pattern matches anywhere in the haystack</span> <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">is_contained_in</span>(<span class="self">self</span>, <span class="ident">haystack</span>: <span class="kw-2">&</span><span class="lifetime">'a</span> <span class="ident">str</span>) <span class="op">-></span> <span class="ident">bool</span> { <span class="self">self</span>.<span class="ident">into_searcher</span>(<span class="ident">haystack</span>).<span class="ident">next_match</span>().<span class="ident">is_some</span>() } <span class="doccomment">/// Checks whether the pattern matches at the front of the haystack</span> <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">is_prefix_of</span>(<span class="self">self</span>, <span class="ident">haystack</span>: <span class="kw-2">&</span><span class="lifetime">'a</span> <span class="ident">str</span>) <span class="op">-></span> <span class="ident">bool</span> { <span class="kw">match</span> <span class="self">self</span>.<span class="ident">into_searcher</span>(<span class="ident">haystack</span>).<span class="ident">next</span>() { <span class="ident">SearchStep</span>::<span class="ident">Match</span>(<span class="number">0</span>, <span class="kw">_</span>) <span class="op">=></span> <span class="bool-val">true</span>, <span class="kw">_</span> <span class="op">=></span> <span class="bool-val">false</span>, } } <span class="doccomment">/// Checks whether the pattern matches at the back of the haystack</span> <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">is_suffix_of</span>(<span class="self">self</span>, <span class="ident">haystack</span>: <span class="kw-2">&</span><span class="lifetime">'a</span> <span class="ident">str</span>) <span class="op">-></span> <span class="ident">bool</span> <span class="kw">where</span> <span class="self">Self</span>::<span class="ident">Searcher</span>: <span class="ident">ReverseSearcher</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> { <span class="kw">match</span> <span class="self">self</span>.<span class="ident">into_searcher</span>(<span class="ident">haystack</span>).<span class="ident">next_back</span>() { <span class="ident">SearchStep</span>::<span class="ident">Match</span>(<span class="kw">_</span>, <span class="ident">j</span>) <span class="kw">if</span> <span class="ident">haystack</span>.<span class="ident">len</span>() <span class="op">==</span> <span class="ident">j</span> <span class="op">=></span> <span class="bool-val">true</span>, <span class="kw">_</span> <span class="op">=></span> <span class="bool-val">false</span>, } } } <span class="comment">// Searcher</span> <span class="doccomment">/// Result of calling `Searcher::next()` or `ReverseSearcher::next_back()`.</span> <span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Copy</span>, <span class="ident">Clone</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>, <span class="ident">Debug</span>)]</span> <span class="kw">pub</span> <span class="kw">enum</span> <span class="ident">SearchStep</span> { <span class="doccomment">/// Expresses that a match of the pattern has been found at</span> <span class="doccomment">/// `haystack[a..b]`.</span> <span class="ident">Match</span>(<span class="ident">usize</span>, <span class="ident">usize</span>), <span class="doccomment">/// Expresses that `haystack[a..b]` has been rejected as a possible match</span> <span class="doccomment">/// of the pattern.</span> <span class="doccomment">///</span> <span class="doccomment">/// Note that there might be more than one `Reject` between two `Match`es,</span> <span class="doccomment">/// there is no requirement for them to be combined into one.</span> <span class="ident">Reject</span>(<span class="ident">usize</span>, <span class="ident">usize</span>), <span class="doccomment">/// Expresses that every byte of the haystack has been visited, ending</span> <span class="doccomment">/// the iteration.</span> <span class="ident">Done</span> } <span class="doccomment">/// A searcher for a string pattern.</span> <span class="doccomment">///</span> <span class="doccomment">/// This trait provides methods for searching for non-overlapping</span> <span class="doccomment">/// matches of a pattern starting from the front (left) of a string.</span> <span class="doccomment">///</span> <span class="doccomment">/// It will be implemented by associated `Searcher`</span> <span class="doccomment">/// types of the `Pattern` trait.</span> <span class="doccomment">///</span> <span class="doccomment">/// The trait is marked unsafe because the indices returned by the</span> <span class="doccomment">/// `next()` methods are required to lie on valid utf8 boundaries in</span> <span class="doccomment">/// the haystack. This enables consumers of this trait to</span> <span class="doccomment">/// slice the haystack without additional runtime checks.</span> <span class="kw">pub</span> <span class="kw">unsafe</span> <span class="kw">trait</span> <span class="ident">Searcher</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> { <span class="doccomment">/// Getter for the underlying string to be searched in</span> <span class="doccomment">///</span> <span class="doccomment">/// Will always return the same `&str`</span> <span class="kw">fn</span> <span class="ident">haystack</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-></span> <span class="kw-2">&</span><span class="lifetime">'a</span> <span class="ident">str</span>; <span class="doccomment">/// Performs the next search step starting from the front.</span> <span class="doccomment">///</span> <span class="doccomment">/// - Returns `Match(a, b)` if `haystack[a..b]` matches the pattern.</span> <span class="doccomment">/// - Returns `Reject(a, b)` if `haystack[a..b]` can not match the</span> <span class="doccomment">/// pattern, even partially.</span> <span class="doccomment">/// - Returns `Done` if every byte of the haystack has been visited</span> <span class="doccomment">///</span> <span class="doccomment">/// The stream of `Match` and `Reject` values up to a `Done`</span> <span class="doccomment">/// will contain index ranges that are adjacent, non-overlapping,</span> <span class="doccomment">/// covering the whole haystack, and laying on utf8 boundaries.</span> <span class="doccomment">///</span> <span class="doccomment">/// A `Match` result needs to contain the whole matched pattern,</span> <span class="doccomment">/// however `Reject` results may be split up into arbitrary</span> <span class="doccomment">/// many adjacent fragments. Both ranges may have zero length.</span> <span class="doccomment">///</span> <span class="doccomment">/// As an example, the pattern `"aaa"` and the haystack `"cbaaaaab"`</span> <span class="doccomment">/// might produce the stream</span> <span class="doccomment">/// `[Reject(0, 1), Reject(1, 2), Match(2, 5), Reject(5, 8)]`</span> <span class="kw">fn</span> <span class="ident">next</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="ident">SearchStep</span>; <span class="doccomment">/// Find the next `Match` result. See `next()`</span> <span class="doccomment">///</span> <span class="doccomment">/// Unlike next(), there is no guarantee that the returned ranges</span> <span class="doccomment">/// of this and next_reject will overlap. This will return (start_match, end_match),</span> <span class="doccomment">/// where start_match is the index of where the match begins, and end_match is</span> <span class="doccomment">/// the index after the end of the match.</span> <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">next_match</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="prelude-ty">Option</span><span class="op"><</span>(<span class="ident">usize</span>, <span class="ident">usize</span>)<span class="op">></span> { <span class="kw">loop</span> { <span class="kw">match</span> <span class="self">self</span>.<span class="ident">next</span>() { <span class="ident">SearchStep</span>::<span class="ident">Match</span>(<span class="ident">a</span>, <span class="ident">b</span>) <span class="op">=></span> <span class="kw">return</span> <span class="prelude-val">Some</span>((<span class="ident">a</span>, <span class="ident">b</span>)), <span class="ident">SearchStep</span>::<span class="ident">Done</span> <span class="op">=></span> <span class="kw">return</span> <span class="prelude-val">None</span>, <span class="kw">_</span> <span class="op">=></span> <span class="kw">continue</span>, } } } <span class="doccomment">/// Find the next `Reject` result. See `next()` and `next_match()`</span> <span class="doccomment">///</span> <span class="doccomment">/// Unlike next(), there is no guarantee that the returned ranges</span> <span class="doccomment">/// of this and next_match will overlap.</span> <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">next_reject</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="prelude-ty">Option</span><span class="op"><</span>(<span class="ident">usize</span>, <span class="ident">usize</span>)<span class="op">></span> { <span class="kw">loop</span> { <span class="kw">match</span> <span class="self">self</span>.<span class="ident">next</span>() { <span class="ident">SearchStep</span>::<span class="ident">Reject</span>(<span class="ident">a</span>, <span class="ident">b</span>) <span class="op">=></span> <span class="kw">return</span> <span class="prelude-val">Some</span>((<span class="ident">a</span>, <span class="ident">b</span>)), <span class="ident">SearchStep</span>::<span class="ident">Done</span> <span class="op">=></span> <span class="kw">return</span> <span class="prelude-val">None</span>, <span class="kw">_</span> <span class="op">=></span> <span class="kw">continue</span>, } } } } <span class="doccomment">/// A reverse searcher for a string pattern.</span> <span class="doccomment">///</span> <span class="doccomment">/// This trait provides methods for searching for non-overlapping</span> <span class="doccomment">/// matches of a pattern starting from the back (right) of a string.</span> <span class="doccomment">///</span> <span class="doccomment">/// It will be implemented by associated `Searcher`</span> <span class="doccomment">/// types of the `Pattern` trait if the pattern supports searching</span> <span class="doccomment">/// for it from the back.</span> <span class="doccomment">///</span> <span class="doccomment">/// The index ranges returned by this trait are not required</span> <span class="doccomment">/// to exactly match those of the forward search in reverse.</span> <span class="doccomment">///</span> <span class="doccomment">/// For the reason why this trait is marked unsafe, see them</span> <span class="doccomment">/// parent trait `Searcher`.</span> <span class="kw">pub</span> <span class="kw">unsafe</span> <span class="kw">trait</span> <span class="ident">ReverseSearcher</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span>: <span class="ident">Searcher</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> { <span class="doccomment">/// Performs the next search step starting from the back.</span> <span class="doccomment">///</span> <span class="doccomment">/// - Returns `Match(a, b)` if `haystack[a..b]` matches the pattern.</span> <span class="doccomment">/// - Returns `Reject(a, b)` if `haystack[a..b]` can not match the</span> <span class="doccomment">/// pattern, even partially.</span> <span class="doccomment">/// - Returns `Done` if every byte of the haystack has been visited</span> <span class="doccomment">///</span> <span class="doccomment">/// The stream of `Match` and `Reject` values up to a `Done`</span> <span class="doccomment">/// will contain index ranges that are adjacent, non-overlapping,</span> <span class="doccomment">/// covering the whole haystack, and laying on utf8 boundaries.</span> <span class="doccomment">///</span> <span class="doccomment">/// A `Match` result needs to contain the whole matched pattern,</span> <span class="doccomment">/// however `Reject` results may be split up into arbitrary</span> <span class="doccomment">/// many adjacent fragments. Both ranges may have zero length.</span> <span class="doccomment">///</span> <span class="doccomment">/// As an example, the pattern `"aaa"` and the haystack `"cbaaaaab"`</span> <span class="doccomment">/// might produce the stream</span> <span class="doccomment">/// `[Reject(7, 8), Match(4, 7), Reject(1, 4), Reject(0, 1)]`</span> <span class="kw">fn</span> <span class="ident">next_back</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="ident">SearchStep</span>; <span class="doccomment">/// Find the next `Match` result. See `next_back()`</span> <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">next_match_back</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="prelude-ty">Option</span><span class="op"><</span>(<span class="ident">usize</span>, <span class="ident">usize</span>)<span class="op">></span>{ <span class="kw">loop</span> { <span class="kw">match</span> <span class="self">self</span>.<span class="ident">next_back</span>() { <span class="ident">SearchStep</span>::<span class="ident">Match</span>(<span class="ident">a</span>, <span class="ident">b</span>) <span class="op">=></span> <span class="kw">return</span> <span class="prelude-val">Some</span>((<span class="ident">a</span>, <span class="ident">b</span>)), <span class="ident">SearchStep</span>::<span class="ident">Done</span> <span class="op">=></span> <span class="kw">return</span> <span class="prelude-val">None</span>, <span class="kw">_</span> <span class="op">=></span> <span class="kw">continue</span>, } } } <span class="doccomment">/// Find the next `Reject` result. See `next_back()`</span> <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">next_reject_back</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="prelude-ty">Option</span><span class="op"><</span>(<span class="ident">usize</span>, <span class="ident">usize</span>)<span class="op">></span>{ <span class="kw">loop</span> { <span class="kw">match</span> <span class="self">self</span>.<span class="ident">next_back</span>() { <span class="ident">SearchStep</span>::<span class="ident">Reject</span>(<span class="ident">a</span>, <span class="ident">b</span>) <span class="op">=></span> <span class="kw">return</span> <span class="prelude-val">Some</span>((<span class="ident">a</span>, <span class="ident">b</span>)), <span class="ident">SearchStep</span>::<span class="ident">Done</span> <span class="op">=></span> <span class="kw">return</span> <span class="prelude-val">None</span>, <span class="kw">_</span> <span class="op">=></span> <span class="kw">continue</span>, } } } } <span class="doccomment">/// A marker trait to express that a `ReverseSearcher`</span> <span class="doccomment">/// can be used for a `DoubleEndedIterator` implementation.</span> <span class="doccomment">///</span> <span class="doccomment">/// For this, the impl of `Searcher` and `ReverseSearcher` need</span> <span class="doccomment">/// to follow these conditions:</span> <span class="doccomment">///</span> <span class="doccomment">/// - All results of `next()` need to be identical</span> <span class="doccomment">/// to the results of `next_back()` in reverse order.</span> <span class="doccomment">/// - `next()` and `next_back()` need to behave as</span> <span class="doccomment">/// the two ends of a range of values, that is they</span> <span class="doccomment">/// can not "walk past each other".</span> <span class="doccomment">///</span> <span class="doccomment">/// # Examples</span> <span class="doccomment">///</span> <span class="doccomment">/// `char::Searcher` is a `DoubleEndedSearcher` because searching for a</span> <span class="doccomment">/// `char` only requires looking at one at a time, which behaves the same</span> <span class="doccomment">/// from both ends.</span> <span class="doccomment">///</span> <span class="doccomment">/// `(&str)::Searcher` is not a `DoubleEndedSearcher` because</span> <span class="doccomment">/// the pattern `"aa"` in the haystack `"aaa"` matches as either</span> <span class="doccomment">/// `"[aa]a"` or `"a[aa]"`, depending from which side it is searched.</span> <span class="kw">pub</span> <span class="kw">trait</span> <span class="ident">DoubleEndedSearcher</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span>: <span class="ident">ReverseSearcher</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> {} <span class="comment">/////////////////////////////////////////////////////////////////////////////</span> <span class="comment">// Impl for char</span> <span class="comment">/////////////////////////////////////////////////////////////////////////////</span> <span class="doccomment">/// Associated type for `<char as Pattern<'a>>::Searcher`.</span> <span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>)]</span> <span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">CharSearcher</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> { <span class="ident">haystack</span>: <span class="kw-2">&</span><span class="lifetime">'a</span> <span class="ident">str</span>, <span class="comment">// safety invariant: `finger`/`finger_back` must be a valid utf8 byte index of `haystack`</span> <span class="comment">// This invariant can be broken *within* next_match and next_match_back, however</span> <span class="comment">// they must exit with fingers on valid code point boundaries.</span> <span class="doccomment">/// `finger` is the current byte index of the forward search.</span> <span class="doccomment">/// Imagine that it exists before the byte at its index, i.e.</span> <span class="doccomment">/// `haystack[finger]` is the first byte of the slice we must inspect during</span> <span class="doccomment">/// forward searching</span> <span class="ident">finger</span>: <span class="ident">usize</span>, <span class="doccomment">/// `finger_back` is the current byte index of the reverse search.</span> <span class="doccomment">/// Imagine that it exists after the byte at its index, i.e.</span> <span class="doccomment">/// haystack[finger_back - 1] is the last byte of the slice we must inspect during</span> <span class="doccomment">/// forward searching (and thus the first byte to be inspected when calling next_back())</span> <span class="ident">finger_back</span>: <span class="ident">usize</span>, <span class="doccomment">/// The character being searched for</span> <span class="ident">needle</span>: <span class="ident">char</span>, <span class="comment">// safety invariant: `utf8_size` must be less than 5</span> <span class="doccomment">/// The number of bytes `needle` takes up when encoded in utf8</span> <span class="ident">utf8_size</span>: <span class="ident">usize</span>, <span class="doccomment">/// A utf8 encoded copy of the `needle`</span> <span class="ident">utf8_encoded</span>: [<span class="ident">u8</span>; <span class="number">4</span>], } <span class="kw">unsafe</span> <span class="kw">impl</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> <span class="ident">Searcher</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> <span class="kw">for</span> <span class="ident">CharSearcher</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> { <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">haystack</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-></span> <span class="kw-2">&</span><span class="lifetime">'a</span> <span class="ident">str</span> { <span class="self">self</span>.<span class="ident">haystack</span> } <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">next</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="ident">SearchStep</span> { <span class="kw">let</span> <span class="ident">old_finger</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">finger</span>; <span class="kw">let</span> <span class="ident">slice</span> <span class="op">=</span> <span class="kw">unsafe</span> { <span class="self">self</span>.<span class="ident">haystack</span>.<span class="ident">get_unchecked</span>(<span class="ident">old_finger</span>..<span class="self">self</span>.<span class="ident">finger_back</span>) }; <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">iter</span> <span class="op">=</span> <span class="ident">slice</span>.<span class="ident">chars</span>(); <span class="kw">let</span> <span class="ident">old_len</span> <span class="op">=</span> <span class="ident">iter</span>.<span class="ident">iter</span>.<span class="ident">len</span>(); <span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="ident">ch</span>) <span class="op">=</span> <span class="ident">iter</span>.<span class="ident">next</span>() { <span class="comment">// add byte offset of current character</span> <span class="comment">// without re-encoding as utf-8</span> <span class="self">self</span>.<span class="ident">finger</span> <span class="op">+=</span> <span class="ident">old_len</span> <span class="op">-</span> <span class="ident">iter</span>.<span class="ident">iter</span>.<span class="ident">len</span>(); <span class="kw">if</span> <span class="ident">ch</span> <span class="op">==</span> <span class="self">self</span>.<span class="ident">needle</span> { <span class="ident">SearchStep</span>::<span class="ident">Match</span>(<span class="ident">old_finger</span>, <span class="self">self</span>.<span class="ident">finger</span>) } <span class="kw">else</span> { <span class="ident">SearchStep</span>::<span class="ident">Reject</span>(<span class="ident">old_finger</span>, <span class="self">self</span>.<span class="ident">finger</span>) } } <span class="kw">else</span> { <span class="ident">SearchStep</span>::<span class="ident">Done</span> } } <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">next_match</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="prelude-ty">Option</span><span class="op"><</span>(<span class="ident">usize</span>, <span class="ident">usize</span>)<span class="op">></span> { <span class="kw">loop</span> { <span class="comment">// get the haystack after the last character found</span> <span class="kw">let</span> <span class="ident">bytes</span> <span class="op">=</span> <span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="ident">slice</span>) <span class="op">=</span> <span class="self">self</span>.<span class="ident">haystack</span>.<span class="ident">as_bytes</span>() .<span class="ident">get</span>(<span class="self">self</span>.<span class="ident">finger</span>..<span class="self">self</span>.<span class="ident">finger_back</span>) { <span class="ident">slice</span> } <span class="kw">else</span> { <span class="kw">return</span> <span class="prelude-val">None</span>; }; <span class="comment">// the last byte of the utf8 encoded needle</span> <span class="kw">let</span> <span class="ident">last_byte</span> <span class="op">=</span> <span class="kw">unsafe</span> { <span class="kw-2">*</span><span class="self">self</span>.<span class="ident">utf8_encoded</span>.<span class="ident">get_unchecked</span>(<span class="self">self</span>.<span class="ident">utf8_size</span> <span class="op">-</span> <span class="number">1</span>) }; <span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="ident">index</span>) <span class="op">=</span> <span class="ident">memchr</span>::<span class="ident">memchr</span>(<span class="ident">last_byte</span>, <span class="ident">bytes</span>) { <span class="comment">// The new finger is the index of the byte we found,</span> <span class="comment">// plus one, since we memchr'd for the last byte of the character.</span> <span class="comment">//</span> <span class="comment">// Note that this doesn't always give us a finger on a UTF8 boundary.</span> <span class="comment">// If we *didn't* find our character</span> <span class="comment">// we may have indexed to the non-last byte of a 3-byte or 4-byte character.</span> <span class="comment">// We can't just skip to the next valid starting byte because a character like</span> <span class="comment">// ꁁ (U+A041 YI SYLLABLE PA), utf-8 `EA 81 81` will have us always find</span> <span class="comment">// the second byte when searching for the third.</span> <span class="comment">//</span> <span class="comment">// However, this is totally okay. While we have the invariant that</span> <span class="comment">// self.finger is on a UTF8 boundary, this invariant is not relied upon</span> <span class="comment">// within this method (it is relied upon in CharSearcher::next()).</span> <span class="comment">//</span> <span class="comment">// We only exit this method when we reach the end of the string, or if we</span> <span class="comment">// find something. When we find something the `finger` will be set</span> <span class="comment">// to a UTF8 boundary.</span> <span class="self">self</span>.<span class="ident">finger</span> <span class="op">+=</span> <span class="ident">index</span> <span class="op">+</span> <span class="number">1</span>; <span class="kw">if</span> <span class="self">self</span>.<span class="ident">finger</span> <span class="op">>=</span> <span class="self">self</span>.<span class="ident">utf8_size</span> { <span class="kw">let</span> <span class="ident">found_char</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">finger</span> <span class="op">-</span> <span class="self">self</span>.<span class="ident">utf8_size</span>; <span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="ident">slice</span>) <span class="op">=</span> <span class="self">self</span>.<span class="ident">haystack</span>.<span class="ident">as_bytes</span>().<span class="ident">get</span>(<span class="ident">found_char</span>..<span class="self">self</span>.<span class="ident">finger</span>) { <span class="kw">if</span> <span class="ident">slice</span> <span class="op">==</span> <span class="kw-2">&</span><span class="self">self</span>.<span class="ident">utf8_encoded</span>[<span class="number">0</span>..<span class="self">self</span>.<span class="ident">utf8_size</span>] { <span class="kw">return</span> <span class="prelude-val">Some</span>((<span class="ident">found_char</span>, <span class="self">self</span>.<span class="ident">finger</span>)); } } } } <span class="kw">else</span> { <span class="comment">// found nothing, exit</span> <span class="self">self</span>.<span class="ident">finger</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">finger_back</span>; <span class="kw">return</span> <span class="prelude-val">None</span>; } } } <span class="comment">// let next_reject use the default implementation from the Searcher trait</span> } <span class="kw">unsafe</span> <span class="kw">impl</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> <span class="ident">ReverseSearcher</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> <span class="kw">for</span> <span class="ident">CharSearcher</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> { <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">next_back</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="ident">SearchStep</span> { <span class="kw">let</span> <span class="ident">old_finger</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">finger_back</span>; <span class="kw">let</span> <span class="ident">slice</span> <span class="op">=</span> <span class="kw">unsafe</span> { <span class="self">self</span>.<span class="ident">haystack</span>.<span class="ident">slice_unchecked</span>(<span class="self">self</span>.<span class="ident">finger</span>, <span class="ident">old_finger</span>) }; <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">iter</span> <span class="op">=</span> <span class="ident">slice</span>.<span class="ident">chars</span>(); <span class="kw">let</span> <span class="ident">old_len</span> <span class="op">=</span> <span class="ident">iter</span>.<span class="ident">iter</span>.<span class="ident">len</span>(); <span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="ident">ch</span>) <span class="op">=</span> <span class="ident">iter</span>.<span class="ident">next_back</span>() { <span class="comment">// subtract byte offset of current character</span> <span class="comment">// without re-encoding as utf-8</span> <span class="self">self</span>.<span class="ident">finger_back</span> <span class="op">-=</span> <span class="ident">old_len</span> <span class="op">-</span> <span class="ident">iter</span>.<span class="ident">iter</span>.<span class="ident">len</span>(); <span class="kw">if</span> <span class="ident">ch</span> <span class="op">==</span> <span class="self">self</span>.<span class="ident">needle</span> { <span class="ident">SearchStep</span>::<span class="ident">Match</span>(<span class="self">self</span>.<span class="ident">finger_back</span>, <span class="ident">old_finger</span>) } <span class="kw">else</span> { <span class="ident">SearchStep</span>::<span class="ident">Reject</span>(<span class="self">self</span>.<span class="ident">finger_back</span>, <span class="ident">old_finger</span>) } } <span class="kw">else</span> { <span class="ident">SearchStep</span>::<span class="ident">Done</span> } } <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">next_match_back</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="prelude-ty">Option</span><span class="op"><</span>(<span class="ident">usize</span>, <span class="ident">usize</span>)<span class="op">></span> { <span class="kw">let</span> <span class="ident">haystack</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">haystack</span>.<span class="ident">as_bytes</span>(); <span class="kw">loop</span> { <span class="comment">// get the haystack up to but not including the last character searched</span> <span class="kw">let</span> <span class="ident">bytes</span> <span class="op">=</span> <span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="ident">slice</span>) <span class="op">=</span> <span class="ident">haystack</span>.<span class="ident">get</span>(<span class="self">self</span>.<span class="ident">finger</span>..<span class="self">self</span>.<span class="ident">finger_back</span>) { <span class="ident">slice</span> } <span class="kw">else</span> { <span class="kw">return</span> <span class="prelude-val">None</span>; }; <span class="comment">// the last byte of the utf8 encoded needle</span> <span class="kw">let</span> <span class="ident">last_byte</span> <span class="op">=</span> <span class="kw">unsafe</span> { <span class="kw-2">*</span><span class="self">self</span>.<span class="ident">utf8_encoded</span>.<span class="ident">get_unchecked</span>(<span class="self">self</span>.<span class="ident">utf8_size</span> <span class="op">-</span> <span class="number">1</span>) }; <span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="ident">index</span>) <span class="op">=</span> <span class="ident">memchr</span>::<span class="ident">memrchr</span>(<span class="ident">last_byte</span>, <span class="ident">bytes</span>) { <span class="comment">// we searched a slice that was offset by self.finger,</span> <span class="comment">// add self.finger to recoup the original index</span> <span class="kw">let</span> <span class="ident">index</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">finger</span> <span class="op">+</span> <span class="ident">index</span>; <span class="comment">// memrchr will return the index of the byte we wish to</span> <span class="comment">// find. In case of an ASCII character, this is indeed</span> <span class="comment">// were we wish our new finger to be ("after" the found</span> <span class="comment">// char in the paradigm of reverse iteration). For</span> <span class="comment">// multibyte chars we need to skip down by the number of more</span> <span class="comment">// bytes they have than ASCII</span> <span class="kw">let</span> <span class="ident">shift</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">utf8_size</span> <span class="op">-</span> <span class="number">1</span>; <span class="kw">if</span> <span class="ident">index</span> <span class="op">>=</span> <span class="ident">shift</span> { <span class="kw">let</span> <span class="ident">found_char</span> <span class="op">=</span> <span class="ident">index</span> <span class="op">-</span> <span class="ident">shift</span>; <span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="ident">slice</span>) <span class="op">=</span> <span class="ident">haystack</span>.<span class="ident">get</span>(<span class="ident">found_char</span>..(<span class="ident">found_char</span> <span class="op">+</span> <span class="self">self</span>.<span class="ident">utf8_size</span>)) { <span class="kw">if</span> <span class="ident">slice</span> <span class="op">==</span> <span class="kw-2">&</span><span class="self">self</span>.<span class="ident">utf8_encoded</span>[<span class="number">0</span>..<span class="self">self</span>.<span class="ident">utf8_size</span>] { <span class="comment">// move finger to before the character found (i.e. at its start index)</span> <span class="self">self</span>.<span class="ident">finger_back</span> <span class="op">=</span> <span class="ident">found_char</span>; <span class="kw">return</span> <span class="prelude-val">Some</span>((<span class="self">self</span>.<span class="ident">finger_back</span>, <span class="self">self</span>.<span class="ident">finger_back</span> <span class="op">+</span> <span class="self">self</span>.<span class="ident">utf8_size</span>)); } } } <span class="comment">// We can't use finger_back = index - size + 1 here. If we found the last char</span> <span class="comment">// of a different-sized character (or the middle byte of a different character)</span> <span class="comment">// we need to bump the finger_back down to `index`. This similarly makes</span> <span class="comment">// `finger_back` have the potential to no longer be on a boundary,</span> <span class="comment">// but this is OK since we only exit this function on a boundary</span> <span class="comment">// or when the haystack has been searched completely.</span> <span class="comment">//</span> <span class="comment">// Unlike next_match this does not</span> <span class="comment">// have the problem of repeated bytes in utf-8 because</span> <span class="comment">// we're searching for the last byte, and we can only have</span> <span class="comment">// found the last byte when searching in reverse.</span> <span class="self">self</span>.<span class="ident">finger_back</span> <span class="op">=</span> <span class="ident">index</span>; } <span class="kw">else</span> { <span class="self">self</span>.<span class="ident">finger_back</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">finger</span>; <span class="comment">// found nothing, exit</span> <span class="kw">return</span> <span class="prelude-val">None</span>; } } } <span class="comment">// let next_reject_back use the default implementation from the Searcher trait</span> } <span class="kw">impl</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> <span class="ident">DoubleEndedSearcher</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> <span class="kw">for</span> <span class="ident">CharSearcher</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> {} <span class="doccomment">/// Searches for chars that are equal to a given char</span> <span class="kw">impl</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> <span class="ident">Pattern</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> <span class="kw">for</span> <span class="ident">char</span> { <span class="kw">type</span> <span class="ident">Searcher</span> <span class="op">=</span> <span class="ident">CharSearcher</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span>; <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">into_searcher</span>(<span class="self">self</span>, <span class="ident">haystack</span>: <span class="kw-2">&</span><span class="lifetime">'a</span> <span class="ident">str</span>) <span class="op">-></span> <span class="self">Self</span>::<span class="ident">Searcher</span> { <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">utf8_encoded</span> <span class="op">=</span> [<span class="number">0</span>; <span class="number">4</span>]; <span class="self">self</span>.<span class="ident">encode_utf8</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">utf8_encoded</span>); <span class="kw">let</span> <span class="ident">utf8_size</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">len_utf8</span>(); <span class="ident">CharSearcher</span> { <span class="ident">haystack</span>, <span class="ident">finger</span>: <span class="number">0</span>, <span class="ident">finger_back</span>: <span class="ident">haystack</span>.<span class="ident">len</span>(), <span class="ident">needle</span>: <span class="self">self</span>, <span class="ident">utf8_size</span>, <span class="ident">utf8_encoded</span> } } <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">is_contained_in</span>(<span class="self">self</span>, <span class="ident">haystack</span>: <span class="kw-2">&</span><span class="lifetime">'a</span> <span class="ident">str</span>) <span class="op">-></span> <span class="ident">bool</span> { <span class="kw">if</span> (<span class="self">self</span> <span class="kw">as</span> <span class="ident">u32</span>) <span class="op"><</span> <span class="number">128</span> { <span class="ident">haystack</span>.<span class="ident">as_bytes</span>().<span class="ident">contains</span>(<span class="kw-2">&</span>(<span class="self">self</span> <span class="kw">as</span> <span class="ident">u8</span>)) } <span class="kw">else</span> { <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">buffer</span> <span class="op">=</span> [<span class="number">0u8</span>; <span class="number">4</span>]; <span class="self">self</span>.<span class="ident">encode_utf8</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">buffer</span>).<span class="ident">is_contained_in</span>(<span class="ident">haystack</span>) } } <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">is_prefix_of</span>(<span class="self">self</span>, <span class="ident">haystack</span>: <span class="kw-2">&</span><span class="lifetime">'a</span> <span class="ident">str</span>) <span class="op">-></span> <span class="ident">bool</span> { <span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="ident">ch</span>) <span class="op">=</span> <span class="ident">haystack</span>.<span class="ident">chars</span>().<span class="ident">next</span>() { <span class="self">self</span> <span class="op">==</span> <span class="ident">ch</span> } <span class="kw">else</span> { <span class="bool-val">false</span> } } <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">is_suffix_of</span>(<span class="self">self</span>, <span class="ident">haystack</span>: <span class="kw-2">&</span><span class="lifetime">'a</span> <span class="ident">str</span>) <span class="op">-></span> <span class="ident">bool</span> <span class="kw">where</span> <span class="self">Self</span>::<span class="ident">Searcher</span>: <span class="ident">ReverseSearcher</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> { <span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="ident">ch</span>) <span class="op">=</span> <span class="ident">haystack</span>.<span class="ident">chars</span>().<span class="ident">next_back</span>() { <span class="self">self</span> <span class="op">==</span> <span class="ident">ch</span> } <span class="kw">else</span> { <span class="bool-val">false</span> } } } <span class="comment">/////////////////////////////////////////////////////////////////////////////</span> <span class="comment">// Impl for a MultiCharEq wrapper</span> <span class="comment">/////////////////////////////////////////////////////////////////////////////</span> <span class="attribute">#[<span class="ident">doc</span>(<span class="ident">hidden</span>)]</span> <span class="kw">trait</span> <span class="ident">MultiCharEq</span> { <span class="kw">fn</span> <span class="ident">matches</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">c</span>: <span class="ident">char</span>) <span class="op">-></span> <span class="ident">bool</span>; } <span class="kw">impl</span><span class="op"><</span><span class="ident">F</span><span class="op">></span> <span class="ident">MultiCharEq</span> <span class="kw">for</span> <span class="ident">F</span> <span class="kw">where</span> <span class="ident">F</span>: <span class="ident">FnMut</span>(<span class="ident">char</span>) <span class="op">-></span> <span class="ident">bool</span> { <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">matches</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">c</span>: <span class="ident">char</span>) <span class="op">-></span> <span class="ident">bool</span> { (<span class="kw-2">*</span><span class="self">self</span>)(<span class="ident">c</span>) } } <span class="kw">impl</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> <span class="ident">MultiCharEq</span> <span class="kw">for</span> <span class="kw-2">&</span><span class="lifetime">'a</span> [<span class="ident">char</span>] { <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">matches</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">c</span>: <span class="ident">char</span>) <span class="op">-></span> <span class="ident">bool</span> { <span class="self">self</span>.<span class="ident">iter</span>().<span class="ident">any</span>(<span class="op">|</span><span class="kw-2">&</span><span class="ident">m</span><span class="op">|</span> { <span class="ident">m</span> <span class="op">==</span> <span class="ident">c</span> }) } } <span class="kw">struct</span> <span class="ident">MultiCharEqPattern</span><span class="op"><</span><span class="ident">C</span>: <span class="ident">MultiCharEq</span><span class="op">></span>(<span class="ident">C</span>); <span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>)]</span> <span class="kw">struct</span> <span class="ident">MultiCharEqSearcher</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="ident">C</span>: <span class="ident">MultiCharEq</span><span class="op">></span> { <span class="ident">char_eq</span>: <span class="ident">C</span>, <span class="ident">haystack</span>: <span class="kw-2">&</span><span class="lifetime">'a</span> <span class="ident">str</span>, <span class="ident">char_indices</span>: <span class="kw">super</span>::<span class="ident">CharIndices</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span>, } <span class="kw">impl</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="ident">C</span>: <span class="ident">MultiCharEq</span><span class="op">></span> <span class="ident">Pattern</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> <span class="kw">for</span> <span class="ident">MultiCharEqPattern</span><span class="op"><</span><span class="ident">C</span><span class="op">></span> { <span class="kw">type</span> <span class="ident">Searcher</span> <span class="op">=</span> <span class="ident">MultiCharEqSearcher</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="ident">C</span><span class="op">></span>; <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">into_searcher</span>(<span class="self">self</span>, <span class="ident">haystack</span>: <span class="kw-2">&</span><span class="lifetime">'a</span> <span class="ident">str</span>) <span class="op">-></span> <span class="ident">MultiCharEqSearcher</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="ident">C</span><span class="op">></span> { <span class="ident">MultiCharEqSearcher</span> { <span class="ident">haystack</span>, <span class="ident">char_eq</span>: <span class="self">self</span>.<span class="number">0</span>, <span class="ident">char_indices</span>: <span class="ident">haystack</span>.<span class="ident">char_indices</span>(), } } } <span class="kw">unsafe</span> <span class="kw">impl</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="ident">C</span>: <span class="ident">MultiCharEq</span><span class="op">></span> <span class="ident">Searcher</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> <span class="kw">for</span> <span class="ident">MultiCharEqSearcher</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="ident">C</span><span class="op">></span> { <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">haystack</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-></span> <span class="kw-2">&</span><span class="lifetime">'a</span> <span class="ident">str</span> { <span class="self">self</span>.<span class="ident">haystack</span> } <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">next</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="ident">SearchStep</span> { <span class="kw">let</span> <span class="ident">s</span> <span class="op">=</span> <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>.<span class="ident">char_indices</span>; <span class="comment">// Compare lengths of the internal byte slice iterator</span> <span class="comment">// to find length of current char</span> <span class="kw">let</span> <span class="ident">pre_len</span> <span class="op">=</span> <span class="ident">s</span>.<span class="ident">iter</span>.<span class="ident">iter</span>.<span class="ident">len</span>(); <span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Some</span>((<span class="ident">i</span>, <span class="ident">c</span>)) <span class="op">=</span> <span class="ident">s</span>.<span class="ident">next</span>() { <span class="kw">let</span> <span class="ident">len</span> <span class="op">=</span> <span class="ident">s</span>.<span class="ident">iter</span>.<span class="ident">iter</span>.<span class="ident">len</span>(); <span class="kw">let</span> <span class="ident">char_len</span> <span class="op">=</span> <span class="ident">pre_len</span> <span class="op">-</span> <span class="ident">len</span>; <span class="kw">if</span> <span class="self">self</span>.<span class="ident">char_eq</span>.<span class="ident">matches</span>(<span class="ident">c</span>) { <span class="kw">return</span> <span class="ident">SearchStep</span>::<span class="ident">Match</span>(<span class="ident">i</span>, <span class="ident">i</span> <span class="op">+</span> <span class="ident">char_len</span>); } <span class="kw">else</span> { <span class="kw">return</span> <span class="ident">SearchStep</span>::<span class="ident">Reject</span>(<span class="ident">i</span>, <span class="ident">i</span> <span class="op">+</span> <span class="ident">char_len</span>); } } <span class="ident">SearchStep</span>::<span class="ident">Done</span> } } <span class="kw">unsafe</span> <span class="kw">impl</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="ident">C</span>: <span class="ident">MultiCharEq</span><span class="op">></span> <span class="ident">ReverseSearcher</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> <span class="kw">for</span> <span class="ident">MultiCharEqSearcher</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="ident">C</span><span class="op">></span> { <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">next_back</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="ident">SearchStep</span> { <span class="kw">let</span> <span class="ident">s</span> <span class="op">=</span> <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>.<span class="ident">char_indices</span>; <span class="comment">// Compare lengths of the internal byte slice iterator</span> <span class="comment">// to find length of current char</span> <span class="kw">let</span> <span class="ident">pre_len</span> <span class="op">=</span> <span class="ident">s</span>.<span class="ident">iter</span>.<span class="ident">iter</span>.<span class="ident">len</span>(); <span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Some</span>((<span class="ident">i</span>, <span class="ident">c</span>)) <span class="op">=</span> <span class="ident">s</span>.<span class="ident">next_back</span>() { <span class="kw">let</span> <span class="ident">len</span> <span class="op">=</span> <span class="ident">s</span>.<span class="ident">iter</span>.<span class="ident">iter</span>.<span class="ident">len</span>(); <span class="kw">let</span> <span class="ident">char_len</span> <span class="op">=</span> <span class="ident">pre_len</span> <span class="op">-</span> <span class="ident">len</span>; <span class="kw">if</span> <span class="self">self</span>.<span class="ident">char_eq</span>.<span class="ident">matches</span>(<span class="ident">c</span>) { <span class="kw">return</span> <span class="ident">SearchStep</span>::<span class="ident">Match</span>(<span class="ident">i</span>, <span class="ident">i</span> <span class="op">+</span> <span class="ident">char_len</span>); } <span class="kw">else</span> { <span class="kw">return</span> <span class="ident">SearchStep</span>::<span class="ident">Reject</span>(<span class="ident">i</span>, <span class="ident">i</span> <span class="op">+</span> <span class="ident">char_len</span>); } } <span class="ident">SearchStep</span>::<span class="ident">Done</span> } } <span class="kw">impl</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="ident">C</span>: <span class="ident">MultiCharEq</span><span class="op">></span> <span class="ident">DoubleEndedSearcher</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> <span class="kw">for</span> <span class="ident">MultiCharEqSearcher</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="ident">C</span><span class="op">></span> {} <span class="comment">/////////////////////////////////////////////////////////////////////////////</span> <span class="macro">macro_rules</span><span class="macro">!</span> <span class="ident">pattern_methods</span> { (<span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>:<span class="ident">ty</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">pmap</span>:<span class="ident">expr</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">smap</span>:<span class="ident">expr</span>) <span class="op">=></span> { <span class="kw">type</span> <span class="ident">Searcher</span> <span class="op">=</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>; <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">into_searcher</span>(<span class="self">self</span>, <span class="ident">haystack</span>: <span class="kw-2">&</span><span class="lifetime">'a</span> <span class="ident">str</span>) <span class="op">-></span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span> { (<span class="macro-nonterminal">$</span><span class="macro-nonterminal">smap</span>)((<span class="macro-nonterminal">$</span><span class="macro-nonterminal">pmap</span>)(<span class="self">self</span>).<span class="ident">into_searcher</span>(<span class="ident">haystack</span>)) } <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">is_contained_in</span>(<span class="self">self</span>, <span class="ident">haystack</span>: <span class="kw-2">&</span><span class="lifetime">'a</span> <span class="ident">str</span>) <span class="op">-></span> <span class="ident">bool</span> { (<span class="macro-nonterminal">$</span><span class="macro-nonterminal">pmap</span>)(<span class="self">self</span>).<span class="ident">is_contained_in</span>(<span class="ident">haystack</span>) } <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">is_prefix_of</span>(<span class="self">self</span>, <span class="ident">haystack</span>: <span class="kw-2">&</span><span class="lifetime">'a</span> <span class="ident">str</span>) <span class="op">-></span> <span class="ident">bool</span> { (<span class="macro-nonterminal">$</span><span class="macro-nonterminal">pmap</span>)(<span class="self">self</span>).<span class="ident">is_prefix_of</span>(<span class="ident">haystack</span>) } <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">is_suffix_of</span>(<span class="self">self</span>, <span class="ident">haystack</span>: <span class="kw-2">&</span><span class="lifetime">'a</span> <span class="ident">str</span>) <span class="op">-></span> <span class="ident">bool</span> <span class="kw">where</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>: <span class="ident">ReverseSearcher</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> { (<span class="macro-nonterminal">$</span><span class="macro-nonterminal">pmap</span>)(<span class="self">self</span>).<span class="ident">is_suffix_of</span>(<span class="ident">haystack</span>) } } } <span class="macro">macro_rules</span><span class="macro">!</span> <span class="ident">searcher_methods</span> { (<span class="ident">forward</span>) <span class="op">=></span> { <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">haystack</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-></span> <span class="kw-2">&</span><span class="lifetime">'a</span> <span class="ident">str</span> { <span class="self">self</span>.<span class="number">0</span>.<span class="ident">haystack</span>() } <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">next</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="ident">SearchStep</span> { <span class="self">self</span>.<span class="number">0</span>.<span class="ident">next</span>() } <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">next_match</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="prelude-ty">Option</span><span class="op"><</span>(<span class="ident">usize</span>, <span class="ident">usize</span>)<span class="op">></span> { <span class="self">self</span>.<span class="number">0</span>.<span class="ident">next_match</span>() } <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">next_reject</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="prelude-ty">Option</span><span class="op"><</span>(<span class="ident">usize</span>, <span class="ident">usize</span>)<span class="op">></span> { <span class="self">self</span>.<span class="number">0</span>.<span class="ident">next_reject</span>() } }; (<span class="ident">reverse</span>) <span class="op">=></span> { <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">next_back</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="ident">SearchStep</span> { <span class="self">self</span>.<span class="number">0</span>.<span class="ident">next_back</span>() } <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">next_match_back</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="prelude-ty">Option</span><span class="op"><</span>(<span class="ident">usize</span>, <span class="ident">usize</span>)<span class="op">></span> { <span class="self">self</span>.<span class="number">0</span>.<span class="ident">next_match_back</span>() } <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">next_reject_back</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="prelude-ty">Option</span><span class="op"><</span>(<span class="ident">usize</span>, <span class="ident">usize</span>)<span class="op">></span> { <span class="self">self</span>.<span class="number">0</span>.<span class="ident">next_reject_back</span>() } } } <span class="comment">/////////////////////////////////////////////////////////////////////////////</span> <span class="comment">// Impl for &[char]</span> <span class="comment">/////////////////////////////////////////////////////////////////////////////</span> <span class="comment">// Todo: Change / Remove due to ambiguity in meaning.</span> <span class="doccomment">/// Associated type for `<&[char] as Pattern<'a>>::Searcher`.</span> <span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>)]</span> <span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">CharSliceSearcher</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="lifetime">'b</span><span class="op">></span>(<span class="op"><</span><span class="ident">MultiCharEqPattern</span><span class="op"><</span><span class="kw-2">&</span><span class="lifetime">'b</span> [<span class="ident">char</span>]<span class="op">></span> <span class="kw">as</span> <span class="ident">Pattern</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">>></span>::<span class="ident">Searcher</span>); <span class="kw">unsafe</span> <span class="kw">impl</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="lifetime">'b</span><span class="op">></span> <span class="ident">Searcher</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> <span class="kw">for</span> <span class="ident">CharSliceSearcher</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="lifetime">'b</span><span class="op">></span> { <span class="macro">searcher_methods</span><span class="macro">!</span>(<span class="ident">forward</span>); } <span class="kw">unsafe</span> <span class="kw">impl</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="lifetime">'b</span><span class="op">></span> <span class="ident">ReverseSearcher</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> <span class="kw">for</span> <span class="ident">CharSliceSearcher</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="lifetime">'b</span><span class="op">></span> { <span class="macro">searcher_methods</span><span class="macro">!</span>(<span class="ident">reverse</span>); } <span class="kw">impl</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="lifetime">'b</span><span class="op">></span> <span class="ident">DoubleEndedSearcher</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> <span class="kw">for</span> <span class="ident">CharSliceSearcher</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="lifetime">'b</span><span class="op">></span> {} <span class="doccomment">/// Searches for chars that are equal to any of the chars in the array</span> <span class="kw">impl</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="lifetime">'b</span><span class="op">></span> <span class="ident">Pattern</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> <span class="kw">for</span> <span class="kw-2">&</span><span class="lifetime">'b</span> [<span class="ident">char</span>] { <span class="macro">pattern_methods</span><span class="macro">!</span>(<span class="ident">CharSliceSearcher</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="lifetime">'b</span><span class="op">></span>, <span class="ident">MultiCharEqPattern</span>, <span class="ident">CharSliceSearcher</span>); } <span class="comment">/////////////////////////////////////////////////////////////////////////////</span> <span class="comment">// Impl for F: FnMut(char) -> bool</span> <span class="comment">/////////////////////////////////////////////////////////////////////////////</span> <span class="doccomment">/// Associated type for `<F as Pattern<'a>>::Searcher`.</span> <span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>)]</span> <span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">CharPredicateSearcher</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="ident">F</span><span class="op">></span>(<span class="op"><</span><span class="ident">MultiCharEqPattern</span><span class="op"><</span><span class="ident">F</span><span class="op">></span> <span class="kw">as</span> <span class="ident">Pattern</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">>></span>::<span class="ident">Searcher</span>) <span class="kw">where</span> <span class="ident">F</span>: <span class="ident">FnMut</span>(<span class="ident">char</span>) <span class="op">-></span> <span class="ident">bool</span>; <span class="kw">impl</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="ident">F</span><span class="op">></span> <span class="ident">fmt</span>::<span class="ident">Debug</span> <span class="kw">for</span> <span class="ident">CharPredicateSearcher</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="ident">F</span><span class="op">></span> <span class="kw">where</span> <span class="ident">F</span>: <span class="ident">FnMut</span>(<span class="ident">char</span>) <span class="op">-></span> <span class="ident">bool</span> { <span class="kw">fn</span> <span class="ident">fmt</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">f</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">fmt</span>::<span class="ident">Formatter</span>) <span class="op">-></span> <span class="ident">fmt</span>::<span class="prelude-ty">Result</span> { <span class="ident">f</span>.<span class="ident">debug_struct</span>(<span class="string">"CharPredicateSearcher"</span>) .<span class="ident">field</span>(<span class="string">"haystack"</span>, <span class="kw-2">&</span><span class="self">self</span>.<span class="number">0</span>.<span class="ident">haystack</span>) .<span class="ident">field</span>(<span class="string">"char_indices"</span>, <span class="kw-2">&</span><span class="self">self</span>.<span class="number">0</span>.<span class="ident">char_indices</span>) .<span class="ident">finish</span>() } } <span class="kw">unsafe</span> <span class="kw">impl</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="ident">F</span><span class="op">></span> <span class="ident">Searcher</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> <span class="kw">for</span> <span class="ident">CharPredicateSearcher</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="ident">F</span><span class="op">></span> <span class="kw">where</span> <span class="ident">F</span>: <span class="ident">FnMut</span>(<span class="ident">char</span>) <span class="op">-></span> <span class="ident">bool</span> { <span class="macro">searcher_methods</span><span class="macro">!</span>(<span class="ident">forward</span>); } <span class="kw">unsafe</span> <span class="kw">impl</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="ident">F</span><span class="op">></span> <span class="ident">ReverseSearcher</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> <span class="kw">for</span> <span class="ident">CharPredicateSearcher</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="ident">F</span><span class="op">></span> <span class="kw">where</span> <span class="ident">F</span>: <span class="ident">FnMut</span>(<span class="ident">char</span>) <span class="op">-></span> <span class="ident">bool</span> { <span class="macro">searcher_methods</span><span class="macro">!</span>(<span class="ident">reverse</span>); } <span class="kw">impl</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="ident">F</span><span class="op">></span> <span class="ident">DoubleEndedSearcher</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> <span class="kw">for</span> <span class="ident">CharPredicateSearcher</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="ident">F</span><span class="op">></span> <span class="kw">where</span> <span class="ident">F</span>: <span class="ident">FnMut</span>(<span class="ident">char</span>) <span class="op">-></span> <span class="ident">bool</span> {} <span class="doccomment">/// Searches for chars that match the given predicate</span> <span class="kw">impl</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="ident">F</span><span class="op">></span> <span class="ident">Pattern</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> <span class="kw">for</span> <span class="ident">F</span> <span class="kw">where</span> <span class="ident">F</span>: <span class="ident">FnMut</span>(<span class="ident">char</span>) <span class="op">-></span> <span class="ident">bool</span> { <span class="macro">pattern_methods</span><span class="macro">!</span>(<span class="ident">CharPredicateSearcher</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="ident">F</span><span class="op">></span>, <span class="ident">MultiCharEqPattern</span>, <span class="ident">CharPredicateSearcher</span>); } <span class="comment">/////////////////////////////////////////////////////////////////////////////</span> <span class="comment">// Impl for &&str</span> <span class="comment">/////////////////////////////////////////////////////////////////////////////</span> <span class="doccomment">/// Delegates to the `&str` impl.</span> <span class="kw">impl</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="lifetime">'b</span>, <span class="lifetime">'c</span><span class="op">></span> <span class="ident">Pattern</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> <span class="kw">for</span> <span class="kw-2">&</span><span class="lifetime">'c</span> <span class="kw-2">&</span><span class="lifetime">'b</span> <span class="ident">str</span> { <span class="macro">pattern_methods</span><span class="macro">!</span>(<span class="ident">StrSearcher</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="lifetime">'b</span><span class="op">></span>, <span class="op">|</span><span class="kw-2">&</span><span class="ident">s</span><span class="op">|</span> <span class="ident">s</span>, <span class="op">|</span><span class="ident">s</span><span class="op">|</span> <span class="ident">s</span>); } <span class="comment">/////////////////////////////////////////////////////////////////////////////</span> <span class="comment">// Impl for &str</span> <span class="comment">/////////////////////////////////////////////////////////////////////////////</span> <span class="doccomment">/// Non-allocating substring search.</span> <span class="doccomment">///</span> <span class="doccomment">/// Will handle the pattern `""` as returning empty matches at each character</span> <span class="doccomment">/// boundary.</span> <span class="kw">impl</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="lifetime">'b</span><span class="op">></span> <span class="ident">Pattern</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> <span class="kw">for</span> <span class="kw-2">&</span><span class="lifetime">'b</span> <span class="ident">str</span> { <span class="kw">type</span> <span class="ident">Searcher</span> <span class="op">=</span> <span class="ident">StrSearcher</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="lifetime">'b</span><span class="op">></span>; <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">into_searcher</span>(<span class="self">self</span>, <span class="ident">haystack</span>: <span class="kw-2">&</span><span class="lifetime">'a</span> <span class="ident">str</span>) <span class="op">-></span> <span class="ident">StrSearcher</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="lifetime">'b</span><span class="op">></span> { <span class="ident">StrSearcher</span>::<span class="ident">new</span>(<span class="ident">haystack</span>, <span class="self">self</span>) } <span class="doccomment">/// Checks whether the pattern matches at the front of the haystack</span> <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">is_prefix_of</span>(<span class="self">self</span>, <span class="ident">haystack</span>: <span class="kw-2">&</span><span class="lifetime">'a</span> <span class="ident">str</span>) <span class="op">-></span> <span class="ident">bool</span> { <span class="ident">haystack</span>.<span class="ident">is_char_boundary</span>(<span class="self">self</span>.<span class="ident">len</span>()) <span class="op">&&</span> <span class="self">self</span> <span class="op">==</span> <span class="kw-2">&</span><span class="ident">haystack</span>[..<span class="self">self</span>.<span class="ident">len</span>()] } <span class="doccomment">/// Checks whether the pattern matches at the back of the haystack</span> <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">is_suffix_of</span>(<span class="self">self</span>, <span class="ident">haystack</span>: <span class="kw-2">&</span><span class="lifetime">'a</span> <span class="ident">str</span>) <span class="op">-></span> <span class="ident">bool</span> { <span class="self">self</span>.<span class="ident">len</span>() <span class="op"><=</span> <span class="ident">haystack</span>.<span class="ident">len</span>() <span class="op">&&</span> <span class="ident">haystack</span>.<span class="ident">is_char_boundary</span>(<span class="ident">haystack</span>.<span class="ident">len</span>() <span class="op">-</span> <span class="self">self</span>.<span class="ident">len</span>()) <span class="op">&&</span> <span class="self">self</span> <span class="op">==</span> <span class="kw-2">&</span><span class="ident">haystack</span>[<span class="ident">haystack</span>.<span class="ident">len</span>() <span class="op">-</span> <span class="self">self</span>.<span class="ident">len</span>()..] } } <span class="comment">/////////////////////////////////////////////////////////////////////////////</span> <span class="comment">// Two Way substring searcher</span> <span class="comment">/////////////////////////////////////////////////////////////////////////////</span> <span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>)]</span> <span class="doccomment">/// Associated type for `<&str as Pattern<'a>>::Searcher`.</span> <span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">StrSearcher</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="lifetime">'b</span><span class="op">></span> { <span class="ident">haystack</span>: <span class="kw-2">&</span><span class="lifetime">'a</span> <span class="ident">str</span>, <span class="ident">needle</span>: <span class="kw-2">&</span><span class="lifetime">'b</span> <span class="ident">str</span>, <span class="ident">searcher</span>: <span class="ident">StrSearcherImpl</span>, } <span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>)]</span> <span class="kw">enum</span> <span class="ident">StrSearcherImpl</span> { <span class="ident">Empty</span>(<span class="ident">EmptyNeedle</span>), <span class="ident">TwoWay</span>(<span class="ident">TwoWaySearcher</span>), } <span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>)]</span> <span class="kw">struct</span> <span class="ident">EmptyNeedle</span> { <span class="ident">position</span>: <span class="ident">usize</span>, <span class="ident">end</span>: <span class="ident">usize</span>, <span class="ident">is_match_fw</span>: <span class="ident">bool</span>, <span class="ident">is_match_bw</span>: <span class="ident">bool</span>, } <span class="kw">impl</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="lifetime">'b</span><span class="op">></span> <span class="ident">StrSearcher</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="lifetime">'b</span><span class="op">></span> { <span class="kw">fn</span> <span class="ident">new</span>(<span class="ident">haystack</span>: <span class="kw-2">&</span><span class="lifetime">'a</span> <span class="ident">str</span>, <span class="ident">needle</span>: <span class="kw-2">&</span><span class="lifetime">'b</span> <span class="ident">str</span>) <span class="op">-></span> <span class="ident">StrSearcher</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="lifetime">'b</span><span class="op">></span> { <span class="kw">if</span> <span class="ident">needle</span>.<span class="ident">is_empty</span>() { <span class="ident">StrSearcher</span> { <span class="ident">haystack</span>, <span class="ident">needle</span>, <span class="ident">searcher</span>: <span class="ident">StrSearcherImpl</span>::<span class="ident">Empty</span>(<span class="ident">EmptyNeedle</span> { <span class="ident">position</span>: <span class="number">0</span>, <span class="ident">end</span>: <span class="ident">haystack</span>.<span class="ident">len</span>(), <span class="ident">is_match_fw</span>: <span class="bool-val">true</span>, <span class="ident">is_match_bw</span>: <span class="bool-val">true</span>, }), } } <span class="kw">else</span> { <span class="ident">StrSearcher</span> { <span class="ident">haystack</span>, <span class="ident">needle</span>, <span class="ident">searcher</span>: <span class="ident">StrSearcherImpl</span>::<span class="ident">TwoWay</span>( <span class="ident">TwoWaySearcher</span>::<span class="ident">new</span>(<span class="ident">needle</span>.<span class="ident">as_bytes</span>(), <span class="ident">haystack</span>.<span class="ident">len</span>()) ), } } } } <span class="kw">unsafe</span> <span class="kw">impl</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="lifetime">'b</span><span class="op">></span> <span class="ident">Searcher</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> <span class="kw">for</span> <span class="ident">StrSearcher</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="lifetime">'b</span><span class="op">></span> { <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">haystack</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-></span> <span class="kw-2">&</span><span class="lifetime">'a</span> <span class="ident">str</span> { <span class="self">self</span>.<span class="ident">haystack</span> } <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">next</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="ident">SearchStep</span> { <span class="kw">match</span> <span class="self">self</span>.<span class="ident">searcher</span> { <span class="ident">StrSearcherImpl</span>::<span class="ident">Empty</span>(<span class="kw-2">ref</span> <span class="kw-2">mut</span> <span class="ident">searcher</span>) <span class="op">=></span> { <span class="comment">// empty needle rejects every char and matches every empty string between them</span> <span class="kw">let</span> <span class="ident">is_match</span> <span class="op">=</span> <span class="ident">searcher</span>.<span class="ident">is_match_fw</span>; <span class="ident">searcher</span>.<span class="ident">is_match_fw</span> <span class="op">=</span> <span class="op">!</span><span class="ident">searcher</span>.<span class="ident">is_match_fw</span>; <span class="kw">let</span> <span class="ident">pos</span> <span class="op">=</span> <span class="ident">searcher</span>.<span class="ident">position</span>; <span class="kw">match</span> <span class="self">self</span>.<span class="ident">haystack</span>[<span class="ident">pos</span>..].<span class="ident">chars</span>().<span class="ident">next</span>() { <span class="kw">_</span> <span class="kw">if</span> <span class="ident">is_match</span> <span class="op">=></span> <span class="ident">SearchStep</span>::<span class="ident">Match</span>(<span class="ident">pos</span>, <span class="ident">pos</span>), <span class="prelude-val">None</span> <span class="op">=></span> <span class="ident">SearchStep</span>::<span class="ident">Done</span>, <span class="prelude-val">Some</span>(<span class="ident">ch</span>) <span class="op">=></span> { <span class="ident">searcher</span>.<span class="ident">position</span> <span class="op">+=</span> <span class="ident">ch</span>.<span class="ident">len_utf8</span>(); <span class="ident">SearchStep</span>::<span class="ident">Reject</span>(<span class="ident">pos</span>, <span class="ident">searcher</span>.<span class="ident">position</span>) } } } <span class="ident">StrSearcherImpl</span>::<span class="ident">TwoWay</span>(<span class="kw-2">ref</span> <span class="kw-2">mut</span> <span class="ident">searcher</span>) <span class="op">=></span> { <span class="comment">// TwoWaySearcher produces valid *Match* indices that split at char boundaries</span> <span class="comment">// as long as it does correct matching and that haystack and needle are</span> <span class="comment">// valid UTF-8</span> <span class="comment">// *Rejects* from the algorithm can fall on any indices, but we will walk them</span> <span class="comment">// manually to the next character boundary, so that they are utf-8 safe.</span> <span class="kw">if</span> <span class="ident">searcher</span>.<span class="ident">position</span> <span class="op">==</span> <span class="self">self</span>.<span class="ident">haystack</span>.<span class="ident">len</span>() { <span class="kw">return</span> <span class="ident">SearchStep</span>::<span class="ident">Done</span>; } <span class="kw">let</span> <span class="ident">is_long</span> <span class="op">=</span> <span class="ident">searcher</span>.<span class="ident">memory</span> <span class="op">==</span> <span class="ident">usize</span>::<span class="ident">MAX</span>; <span class="kw">match</span> <span class="ident">searcher</span>.<span class="ident">next</span>::<span class="op"><</span><span class="ident">RejectAndMatch</span><span class="op">></span>(<span class="self">self</span>.<span class="ident">haystack</span>.<span class="ident">as_bytes</span>(), <span class="self">self</span>.<span class="ident">needle</span>.<span class="ident">as_bytes</span>(), <span class="ident">is_long</span>) { <span class="ident">SearchStep</span>::<span class="ident">Reject</span>(<span class="ident">a</span>, <span class="kw-2">mut</span> <span class="ident">b</span>) <span class="op">=></span> { <span class="comment">// skip to next char boundary</span> <span class="kw">while</span> <span class="op">!</span><span class="self">self</span>.<span class="ident">haystack</span>.<span class="ident">is_char_boundary</span>(<span class="ident">b</span>) { <span class="ident">b</span> <span class="op">+=</span> <span class="number">1</span>; } <span class="ident">searcher</span>.<span class="ident">position</span> <span class="op">=</span> <span class="ident">cmp</span>::<span class="ident">max</span>(<span class="ident">b</span>, <span class="ident">searcher</span>.<span class="ident">position</span>); <span class="ident">SearchStep</span>::<span class="ident">Reject</span>(<span class="ident">a</span>, <span class="ident">b</span>) } <span class="ident">otherwise</span> <span class="op">=></span> <span class="ident">otherwise</span>, } } } } <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">next_match</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="prelude-ty">Option</span><span class="op"><</span>(<span class="ident">usize</span>, <span class="ident">usize</span>)<span class="op">></span> { <span class="kw">match</span> <span class="self">self</span>.<span class="ident">searcher</span> { <span class="ident">StrSearcherImpl</span>::<span class="ident">Empty</span>(..) <span class="op">=></span> { <span class="kw">loop</span> { <span class="kw">match</span> <span class="self">self</span>.<span class="ident">next</span>() { <span class="ident">SearchStep</span>::<span class="ident">Match</span>(<span class="ident">a</span>, <span class="ident">b</span>) <span class="op">=></span> <span class="kw">return</span> <span class="prelude-val">Some</span>((<span class="ident">a</span>, <span class="ident">b</span>)), <span class="ident">SearchStep</span>::<span class="ident">Done</span> <span class="op">=></span> <span class="kw">return</span> <span class="prelude-val">None</span>, <span class="ident">SearchStep</span>::<span class="ident">Reject</span>(..) <span class="op">=></span> { } } } } <span class="ident">StrSearcherImpl</span>::<span class="ident">TwoWay</span>(<span class="kw-2">ref</span> <span class="kw-2">mut</span> <span class="ident">searcher</span>) <span class="op">=></span> { <span class="kw">let</span> <span class="ident">is_long</span> <span class="op">=</span> <span class="ident">searcher</span>.<span class="ident">memory</span> <span class="op">==</span> <span class="ident">usize</span>::<span class="ident">MAX</span>; <span class="comment">// write out `true` and `false` cases to encourage the compiler</span> <span class="comment">// to specialize the two cases separately.</span> <span class="kw">if</span> <span class="ident">is_long</span> { <span class="ident">searcher</span>.<span class="ident">next</span>::<span class="op"><</span><span class="ident">MatchOnly</span><span class="op">></span>(<span class="self">self</span>.<span class="ident">haystack</span>.<span class="ident">as_bytes</span>(), <span class="self">self</span>.<span class="ident">needle</span>.<span class="ident">as_bytes</span>(), <span class="bool-val">true</span>) } <span class="kw">else</span> { <span class="ident">searcher</span>.<span class="ident">next</span>::<span class="op"><</span><span class="ident">MatchOnly</span><span class="op">></span>(<span class="self">self</span>.<span class="ident">haystack</span>.<span class="ident">as_bytes</span>(), <span class="self">self</span>.<span class="ident">needle</span>.<span class="ident">as_bytes</span>(), <span class="bool-val">false</span>) } } } } } <span class="kw">unsafe</span> <span class="kw">impl</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="lifetime">'b</span><span class="op">></span> <span class="ident">ReverseSearcher</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> <span class="kw">for</span> <span class="ident">StrSearcher</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="lifetime">'b</span><span class="op">></span> { <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">next_back</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="ident">SearchStep</span> { <span class="kw">match</span> <span class="self">self</span>.<span class="ident">searcher</span> { <span class="ident">StrSearcherImpl</span>::<span class="ident">Empty</span>(<span class="kw-2">ref</span> <span class="kw-2">mut</span> <span class="ident">searcher</span>) <span class="op">=></span> { <span class="kw">let</span> <span class="ident">is_match</span> <span class="op">=</span> <span class="ident">searcher</span>.<span class="ident">is_match_bw</span>; <span class="ident">searcher</span>.<span class="ident">is_match_bw</span> <span class="op">=</span> <span class="op">!</span><span class="ident">searcher</span>.<span class="ident">is_match_bw</span>; <span class="kw">let</span> <span class="ident">end</span> <span class="op">=</span> <span class="ident">searcher</span>.<span class="ident">end</span>; <span class="kw">match</span> <span class="self">self</span>.<span class="ident">haystack</span>[..<span class="ident">end</span>].<span class="ident">chars</span>().<span class="ident">next_back</span>() { <span class="kw">_</span> <span class="kw">if</span> <span class="ident">is_match</span> <span class="op">=></span> <span class="ident">SearchStep</span>::<span class="ident">Match</span>(<span class="ident">end</span>, <span class="ident">end</span>), <span class="prelude-val">None</span> <span class="op">=></span> <span class="ident">SearchStep</span>::<span class="ident">Done</span>, <span class="prelude-val">Some</span>(<span class="ident">ch</span>) <span class="op">=></span> { <span class="ident">searcher</span>.<span class="ident">end</span> <span class="op">-=</span> <span class="ident">ch</span>.<span class="ident">len_utf8</span>(); <span class="ident">SearchStep</span>::<span class="ident">Reject</span>(<span class="ident">searcher</span>.<span class="ident">end</span>, <span class="ident">end</span>) } } } <span class="ident">StrSearcherImpl</span>::<span class="ident">TwoWay</span>(<span class="kw-2">ref</span> <span class="kw-2">mut</span> <span class="ident">searcher</span>) <span class="op">=></span> { <span class="kw">if</span> <span class="ident">searcher</span>.<span class="ident">end</span> <span class="op">==</span> <span class="number">0</span> { <span class="kw">return</span> <span class="ident">SearchStep</span>::<span class="ident">Done</span>; } <span class="kw">let</span> <span class="ident">is_long</span> <span class="op">=</span> <span class="ident">searcher</span>.<span class="ident">memory</span> <span class="op">==</span> <span class="ident">usize</span>::<span class="ident">MAX</span>; <span class="kw">match</span> <span class="ident">searcher</span>.<span class="ident">next_back</span>::<span class="op"><</span><span class="ident">RejectAndMatch</span><span class="op">></span>(<span class="self">self</span>.<span class="ident">haystack</span>.<span class="ident">as_bytes</span>(), <span class="self">self</span>.<span class="ident">needle</span>.<span class="ident">as_bytes</span>(), <span class="ident">is_long</span>) { <span class="ident">SearchStep</span>::<span class="ident">Reject</span>(<span class="kw-2">mut</span> <span class="ident">a</span>, <span class="ident">b</span>) <span class="op">=></span> { <span class="comment">// skip to next char boundary</span> <span class="kw">while</span> <span class="op">!</span><span class="self">self</span>.<span class="ident">haystack</span>.<span class="ident">is_char_boundary</span>(<span class="ident">a</span>) { <span class="ident">a</span> <span class="op">-=</span> <span class="number">1</span>; } <span class="ident">searcher</span>.<span class="ident">end</span> <span class="op">=</span> <span class="ident">cmp</span>::<span class="ident">min</span>(<span class="ident">a</span>, <span class="ident">searcher</span>.<span class="ident">end</span>); <span class="ident">SearchStep</span>::<span class="ident">Reject</span>(<span class="ident">a</span>, <span class="ident">b</span>) } <span class="ident">otherwise</span> <span class="op">=></span> <span class="ident">otherwise</span>, } } } } <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">next_match_back</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="prelude-ty">Option</span><span class="op"><</span>(<span class="ident">usize</span>, <span class="ident">usize</span>)<span class="op">></span> { <span class="kw">match</span> <span class="self">self</span>.<span class="ident">searcher</span> { <span class="ident">StrSearcherImpl</span>::<span class="ident">Empty</span>(..) <span class="op">=></span> { <span class="kw">loop</span> { <span class="kw">match</span> <span class="self">self</span>.<span class="ident">next_back</span>() { <span class="ident">SearchStep</span>::<span class="ident">Match</span>(<span class="ident">a</span>, <span class="ident">b</span>) <span class="op">=></span> <span class="kw">return</span> <span class="prelude-val">Some</span>((<span class="ident">a</span>, <span class="ident">b</span>)), <span class="ident">SearchStep</span>::<span class="ident">Done</span> <span class="op">=></span> <span class="kw">return</span> <span class="prelude-val">None</span>, <span class="ident">SearchStep</span>::<span class="ident">Reject</span>(..) <span class="op">=></span> { } } } } <span class="ident">StrSearcherImpl</span>::<span class="ident">TwoWay</span>(<span class="kw-2">ref</span> <span class="kw-2">mut</span> <span class="ident">searcher</span>) <span class="op">=></span> { <span class="kw">let</span> <span class="ident">is_long</span> <span class="op">=</span> <span class="ident">searcher</span>.<span class="ident">memory</span> <span class="op">==</span> <span class="ident">usize</span>::<span class="ident">MAX</span>; <span class="comment">// write out `true` and `false`, like `next_match`</span> <span class="kw">if</span> <span class="ident">is_long</span> { <span class="ident">searcher</span>.<span class="ident">next_back</span>::<span class="op"><</span><span class="ident">MatchOnly</span><span class="op">></span>(<span class="self">self</span>.<span class="ident">haystack</span>.<span class="ident">as_bytes</span>(), <span class="self">self</span>.<span class="ident">needle</span>.<span class="ident">as_bytes</span>(), <span class="bool-val">true</span>) } <span class="kw">else</span> { <span class="ident">searcher</span>.<span class="ident">next_back</span>::<span class="op"><</span><span class="ident">MatchOnly</span><span class="op">></span>(<span class="self">self</span>.<span class="ident">haystack</span>.<span class="ident">as_bytes</span>(), <span class="self">self</span>.<span class="ident">needle</span>.<span class="ident">as_bytes</span>(), <span class="bool-val">false</span>) } } } } } <span class="doccomment">/// The internal state of the two-way substring search algorithm.</span> <span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Debug</span>)]</span> <span class="kw">struct</span> <span class="ident">TwoWaySearcher</span> { <span class="comment">// constants</span> <span class="doccomment">/// critical factorization index</span> <span class="ident">crit_pos</span>: <span class="ident">usize</span>, <span class="doccomment">/// critical factorization index for reversed needle</span> <span class="ident">crit_pos_back</span>: <span class="ident">usize</span>, <span class="ident">period</span>: <span class="ident">usize</span>, <span class="doccomment">/// `byteset` is an extension (not part of the two way algorithm);</span> <span class="doccomment">/// it's a 64-bit "fingerprint" where each set bit `j` corresponds</span> <span class="doccomment">/// to a (byte & 63) == j present in the needle.</span> <span class="ident">byteset</span>: <span class="ident">u64</span>, <span class="comment">// variables</span> <span class="ident">position</span>: <span class="ident">usize</span>, <span class="ident">end</span>: <span class="ident">usize</span>, <span class="doccomment">/// index into needle before which we have already matched</span> <span class="ident">memory</span>: <span class="ident">usize</span>, <span class="doccomment">/// index into needle after which we have already matched</span> <span class="ident">memory_back</span>: <span class="ident">usize</span>, } <span class="comment">/* This is the Two-Way search algorithm, which was introduced in the paper: Crochemore, M., Perrin, D., 1991, Two-way string-matching, Journal of the ACM 38(3):651-675. Here's some background information. A *word* is a string of symbols. The *length* of a word should be a familiar notion, and here we denote it for any word x by |x|. (We also allow for the possibility of the *empty word*, a word of length zero). If x is any non-empty word, then an integer p with 0 < p <= |x| is said to be a *period* for x iff for all i with 0 <= i <= |x| - p - 1, we have x[i] == x[i+p]. For example, both 1 and 2 are periods for the string "aa". As another example, the only period of the string "abcd" is 4. We denote by period(x) the *smallest* period of x (provided that x is non-empty). This is always well-defined since every non-empty word x has at least one period, |x|. We sometimes call this *the period* of x. If u, v and x are words such that x = uv, where uv is the concatenation of u and v, then we say that (u, v) is a *factorization* of x. Let (u, v) be a factorization for a word x. Then if w is a non-empty word such that both of the following hold - either w is a suffix of u or u is a suffix of w - either w is a prefix of v or v is a prefix of w then w is said to be a *repetition* for the factorization (u, v). Just to unpack this, there are four possibilities here. Let w = "abc". Then we might have: - w is a suffix of u and w is a prefix of v. ex: ("lolabc", "abcde") - w is a suffix of u and v is a prefix of w. ex: ("lolabc", "ab") - u is a suffix of w and w is a prefix of v. ex: ("bc", "abchi") - u is a suffix of w and v is a prefix of w. ex: ("bc", "a") Note that the word vu is a repetition for any factorization (u,v) of x = uv, so every factorization has at least one repetition. If x is a string and (u, v) is a factorization for x, then a *local period* for (u, v) is an integer r such that there is some word w such that |w| = r and w is a repetition for (u, v). We denote by local_period(u, v) the smallest local period of (u, v). We sometimes call this *the local period* of (u, v). Provided that x = uv is non-empty, this is well-defined (because each non-empty word has at least one factorization, as noted above). It can be proven that the following is an equivalent definition of a local period for a factorization (u, v): any positive integer r such that x[i] == x[i+r] for all i such that |u| - r <= i <= |u| - 1 and such that both x[i] and x[i+r] are defined. (i.e. i > 0 and i + r < |x|). Using the above reformulation, it is easy to prove that 1 <= local_period(u, v) <= period(uv) A factorization (u, v) of x such that local_period(u,v) = period(x) is called a *critical factorization*. The algorithm hinges on the following theorem, which is stated without proof: **Critical Factorization Theorem** Any word x has at least one critical factorization (u, v) such that |u| < period(x). The purpose of maximal_suffix is to find such a critical factorization. If the period is short, compute another factorization x = u' v' to use for reverse search, chosen instead so that |v'| < period(x). */</span> <span class="kw">impl</span> <span class="ident">TwoWaySearcher</span> { <span class="kw">fn</span> <span class="ident">new</span>(<span class="ident">needle</span>: <span class="kw-2">&</span>[<span class="ident">u8</span>], <span class="ident">end</span>: <span class="ident">usize</span>) <span class="op">-></span> <span class="ident">TwoWaySearcher</span> { <span class="kw">let</span> (<span class="ident">crit_pos_false</span>, <span class="ident">period_false</span>) <span class="op">=</span> <span class="ident">TwoWaySearcher</span>::<span class="ident">maximal_suffix</span>(<span class="ident">needle</span>, <span class="bool-val">false</span>); <span class="kw">let</span> (<span class="ident">crit_pos_true</span>, <span class="ident">period_true</span>) <span class="op">=</span> <span class="ident">TwoWaySearcher</span>::<span class="ident">maximal_suffix</span>(<span class="ident">needle</span>, <span class="bool-val">true</span>); <span class="kw">let</span> (<span class="ident">crit_pos</span>, <span class="ident">period</span>) <span class="op">=</span> <span class="kw">if</span> <span class="ident">crit_pos_false</span> <span class="op">></span> <span class="ident">crit_pos_true</span> { (<span class="ident">crit_pos_false</span>, <span class="ident">period_false</span>) } <span class="kw">else</span> { (<span class="ident">crit_pos_true</span>, <span class="ident">period_true</span>) }; <span class="comment">// A particularly readable explanation of what's going on here can be found</span> <span class="comment">// in Crochemore and Rytter's book "Text Algorithms", ch 13. Specifically</span> <span class="comment">// see the code for "Algorithm CP" on p. 323.</span> <span class="comment">//</span> <span class="comment">// What's going on is we have some critical factorization (u, v) of the</span> <span class="comment">// needle, and we want to determine whether u is a suffix of</span> <span class="comment">// &v[..period]. If it is, we use "Algorithm CP1". Otherwise we use</span> <span class="comment">// "Algorithm CP2", which is optimized for when the period of the needle</span> <span class="comment">// is large.</span> <span class="kw">if</span> <span class="kw-2">&</span><span class="ident">needle</span>[..<span class="ident">crit_pos</span>] <span class="op">==</span> <span class="kw-2">&</span><span class="ident">needle</span>[<span class="ident">period</span>.. <span class="ident">period</span> <span class="op">+</span> <span class="ident">crit_pos</span>] { <span class="comment">// short period case -- the period is exact</span> <span class="comment">// compute a separate critical factorization for the reversed needle</span> <span class="comment">// x = u' v' where |v'| < period(x).</span> <span class="comment">//</span> <span class="comment">// This is sped up by the period being known already.</span> <span class="comment">// Note that a case like x = "acba" may be factored exactly forwards</span> <span class="comment">// (crit_pos = 1, period = 3) while being factored with approximate</span> <span class="comment">// period in reverse (crit_pos = 2, period = 2). We use the given</span> <span class="comment">// reverse factorization but keep the exact period.</span> <span class="kw">let</span> <span class="ident">crit_pos_back</span> <span class="op">=</span> <span class="ident">needle</span>.<span class="ident">len</span>() <span class="op">-</span> <span class="ident">cmp</span>::<span class="ident">max</span>( <span class="ident">TwoWaySearcher</span>::<span class="ident">reverse_maximal_suffix</span>(<span class="ident">needle</span>, <span class="ident">period</span>, <span class="bool-val">false</span>), <span class="ident">TwoWaySearcher</span>::<span class="ident">reverse_maximal_suffix</span>(<span class="ident">needle</span>, <span class="ident">period</span>, <span class="bool-val">true</span>)); <span class="ident">TwoWaySearcher</span> { <span class="ident">crit_pos</span>, <span class="ident">crit_pos_back</span>, <span class="ident">period</span>, <span class="ident">byteset</span>: <span class="self">Self</span>::<span class="ident">byteset_create</span>(<span class="kw-2">&</span><span class="ident">needle</span>[..<span class="ident">period</span>]), <span class="ident">position</span>: <span class="number">0</span>, <span class="ident">end</span>, <span class="ident">memory</span>: <span class="number">0</span>, <span class="ident">memory_back</span>: <span class="ident">needle</span>.<span class="ident">len</span>(), } } <span class="kw">else</span> { <span class="comment">// long period case -- we have an approximation to the actual period,</span> <span class="comment">// and don't use memorization.</span> <span class="comment">//</span> <span class="comment">// Approximate the period by lower bound max(|u|, |v|) + 1.</span> <span class="comment">// The critical factorization is efficient to use for both forward and</span> <span class="comment">// reverse search.</span> <span class="ident">TwoWaySearcher</span> { <span class="ident">crit_pos</span>, <span class="ident">crit_pos_back</span>: <span class="ident">crit_pos</span>, <span class="ident">period</span>: <span class="ident">cmp</span>::<span class="ident">max</span>(<span class="ident">crit_pos</span>, <span class="ident">needle</span>.<span class="ident">len</span>() <span class="op">-</span> <span class="ident">crit_pos</span>) <span class="op">+</span> <span class="number">1</span>, <span class="ident">byteset</span>: <span class="self">Self</span>::<span class="ident">byteset_create</span>(<span class="ident">needle</span>), <span class="ident">position</span>: <span class="number">0</span>, <span class="ident">end</span>, <span class="ident">memory</span>: <span class="ident">usize</span>::<span class="ident">MAX</span>, <span class="comment">// Dummy value to signify that the period is long</span> <span class="ident">memory_back</span>: <span class="ident">usize</span>::<span class="ident">MAX</span>, } } } <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">byteset_create</span>(<span class="ident">bytes</span>: <span class="kw-2">&</span>[<span class="ident">u8</span>]) <span class="op">-></span> <span class="ident">u64</span> { <span class="ident">bytes</span>.<span class="ident">iter</span>().<span class="ident">fold</span>(<span class="number">0</span>, <span class="op">|</span><span class="ident">a</span>, <span class="kw-2">&</span><span class="ident">b</span><span class="op">|</span> (<span class="number">1</span> <span class="op"><<</span> (<span class="ident">b</span> <span class="op">&</span> <span class="number">0x3f</span>)) <span class="op">|</span> <span class="ident">a</span>) } <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">byteset_contains</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">byte</span>: <span class="ident">u8</span>) <span class="op">-></span> <span class="ident">bool</span> { (<span class="self">self</span>.<span class="ident">byteset</span> <span class="op">>></span> ((<span class="ident">byte</span> <span class="op">&</span> <span class="number">0x3f</span>) <span class="kw">as</span> <span class="ident">usize</span>)) <span class="op">&</span> <span class="number">1</span> <span class="op">!=</span> <span class="number">0</span> } <span class="comment">// One of the main ideas of Two-Way is that we factorize the needle into</span> <span class="comment">// two halves, (u, v), and begin trying to find v in the haystack by scanning</span> <span class="comment">// left to right. If v matches, we try to match u by scanning right to left.</span> <span class="comment">// How far we can jump when we encounter a mismatch is all based on the fact</span> <span class="comment">// that (u, v) is a critical factorization for the needle.</span> <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">next</span><span class="op"><</span><span class="ident">S</span><span class="op">></span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">haystack</span>: <span class="kw-2">&</span>[<span class="ident">u8</span>], <span class="ident">needle</span>: <span class="kw-2">&</span>[<span class="ident">u8</span>], <span class="ident">long_period</span>: <span class="ident">bool</span>) <span class="op">-></span> <span class="ident">S</span>::<span class="ident">Output</span> <span class="kw">where</span> <span class="ident">S</span>: <span class="ident">TwoWayStrategy</span> { <span class="comment">// `next()` uses `self.position` as its cursor</span> <span class="kw">let</span> <span class="ident">old_pos</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">position</span>; <span class="kw">let</span> <span class="ident">needle_last</span> <span class="op">=</span> <span class="ident">needle</span>.<span class="ident">len</span>() <span class="op">-</span> <span class="number">1</span>; <span class="lifetime">'search</span>: <span class="kw">loop</span> { <span class="comment">// Check that we have room to search in</span> <span class="comment">// position + needle_last can not overflow if we assume slices</span> <span class="comment">// are bounded by isize's range.</span> <span class="kw">let</span> <span class="ident">tail_byte</span> <span class="op">=</span> <span class="kw">match</span> <span class="ident">haystack</span>.<span class="ident">get</span>(<span class="self">self</span>.<span class="ident">position</span> <span class="op">+</span> <span class="ident">needle_last</span>) { <span class="prelude-val">Some</span>(<span class="kw-2">&</span><span class="ident">b</span>) <span class="op">=></span> <span class="ident">b</span>, <span class="prelude-val">None</span> <span class="op">=></span> { <span class="self">self</span>.<span class="ident">position</span> <span class="op">=</span> <span class="ident">haystack</span>.<span class="ident">len</span>(); <span class="kw">return</span> <span class="ident">S</span>::<span class="ident">rejecting</span>(<span class="ident">old_pos</span>, <span class="self">self</span>.<span class="ident">position</span>); } }; <span class="kw">if</span> <span class="ident">S</span>::<span class="ident">use_early_reject</span>() <span class="op">&&</span> <span class="ident">old_pos</span> <span class="op">!=</span> <span class="self">self</span>.<span class="ident">position</span> { <span class="kw">return</span> <span class="ident">S</span>::<span class="ident">rejecting</span>(<span class="ident">old_pos</span>, <span class="self">self</span>.<span class="ident">position</span>); } <span class="comment">// Quickly skip by large portions unrelated to our substring</span> <span class="kw">if</span> <span class="op">!</span><span class="self">self</span>.<span class="ident">byteset_contains</span>(<span class="ident">tail_byte</span>) { <span class="self">self</span>.<span class="ident">position</span> <span class="op">+=</span> <span class="ident">needle</span>.<span class="ident">len</span>(); <span class="kw">if</span> <span class="op">!</span><span class="ident">long_period</span> { <span class="self">self</span>.<span class="ident">memory</span> <span class="op">=</span> <span class="number">0</span>; } <span class="kw">continue</span> <span class="lifetime">'search</span>; } <span class="comment">// See if the right part of the needle matches</span> <span class="kw">let</span> <span class="ident">start</span> <span class="op">=</span> <span class="kw">if</span> <span class="ident">long_period</span> { <span class="self">self</span>.<span class="ident">crit_pos</span> } <span class="kw">else</span> { <span class="ident">cmp</span>::<span class="ident">max</span>(<span class="self">self</span>.<span class="ident">crit_pos</span>, <span class="self">self</span>.<span class="ident">memory</span>) }; <span class="kw">for</span> <span class="ident">i</span> <span class="kw">in</span> <span class="ident">start</span>..<span class="ident">needle</span>.<span class="ident">len</span>() { <span class="kw">if</span> <span class="ident">needle</span>[<span class="ident">i</span>] <span class="op">!=</span> <span class="ident">haystack</span>[<span class="self">self</span>.<span class="ident">position</span> <span class="op">+</span> <span class="ident">i</span>] { <span class="self">self</span>.<span class="ident">position</span> <span class="op">+=</span> <span class="ident">i</span> <span class="op">-</span> <span class="self">self</span>.<span class="ident">crit_pos</span> <span class="op">+</span> <span class="number">1</span>; <span class="kw">if</span> <span class="op">!</span><span class="ident">long_period</span> { <span class="self">self</span>.<span class="ident">memory</span> <span class="op">=</span> <span class="number">0</span>; } <span class="kw">continue</span> <span class="lifetime">'search</span>; } } <span class="comment">// See if the left part of the needle matches</span> <span class="kw">let</span> <span class="ident">start</span> <span class="op">=</span> <span class="kw">if</span> <span class="ident">long_period</span> { <span class="number">0</span> } <span class="kw">else</span> { <span class="self">self</span>.<span class="ident">memory</span> }; <span class="kw">for</span> <span class="ident">i</span> <span class="kw">in</span> (<span class="ident">start</span>..<span class="self">self</span>.<span class="ident">crit_pos</span>).<span class="ident">rev</span>() { <span class="kw">if</span> <span class="ident">needle</span>[<span class="ident">i</span>] <span class="op">!=</span> <span class="ident">haystack</span>[<span class="self">self</span>.<span class="ident">position</span> <span class="op">+</span> <span class="ident">i</span>] { <span class="self">self</span>.<span class="ident">position</span> <span class="op">+=</span> <span class="self">self</span>.<span class="ident">period</span>; <span class="kw">if</span> <span class="op">!</span><span class="ident">long_period</span> { <span class="self">self</span>.<span class="ident">memory</span> <span class="op">=</span> <span class="ident">needle</span>.<span class="ident">len</span>() <span class="op">-</span> <span class="self">self</span>.<span class="ident">period</span>; } <span class="kw">continue</span> <span class="lifetime">'search</span>; } } <span class="comment">// We have found a match!</span> <span class="kw">let</span> <span class="ident">match_pos</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">position</span>; <span class="comment">// Note: add self.period instead of needle.len() to have overlapping matches</span> <span class="self">self</span>.<span class="ident">position</span> <span class="op">+=</span> <span class="ident">needle</span>.<span class="ident">len</span>(); <span class="kw">if</span> <span class="op">!</span><span class="ident">long_period</span> { <span class="self">self</span>.<span class="ident">memory</span> <span class="op">=</span> <span class="number">0</span>; <span class="comment">// set to needle.len() - self.period for overlapping matches</span> } <span class="kw">return</span> <span class="ident">S</span>::<span class="ident">matching</span>(<span class="ident">match_pos</span>, <span class="ident">match_pos</span> <span class="op">+</span> <span class="ident">needle</span>.<span class="ident">len</span>()); } } <span class="comment">// Follows the ideas in `next()`.</span> <span class="comment">//</span> <span class="comment">// The definitions are symmetrical, with period(x) = period(reverse(x))</span> <span class="comment">// and local_period(u, v) = local_period(reverse(v), reverse(u)), so if (u, v)</span> <span class="comment">// is a critical factorization, so is (reverse(v), reverse(u)).</span> <span class="comment">//</span> <span class="comment">// For the reverse case we have computed a critical factorization x = u' v'</span> <span class="comment">// (field `crit_pos_back`). We need |u| < period(x) for the forward case and</span> <span class="comment">// thus |v'| < period(x) for the reverse.</span> <span class="comment">//</span> <span class="comment">// To search in reverse through the haystack, we search forward through</span> <span class="comment">// a reversed haystack with a reversed needle, matching first u' and then v'.</span> <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">next_back</span><span class="op"><</span><span class="ident">S</span><span class="op">></span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">haystack</span>: <span class="kw-2">&</span>[<span class="ident">u8</span>], <span class="ident">needle</span>: <span class="kw-2">&</span>[<span class="ident">u8</span>], <span class="ident">long_period</span>: <span class="ident">bool</span>) <span class="op">-></span> <span class="ident">S</span>::<span class="ident">Output</span> <span class="kw">where</span> <span class="ident">S</span>: <span class="ident">TwoWayStrategy</span> { <span class="comment">// `next_back()` uses `self.end` as its cursor -- so that `next()` and `next_back()`</span> <span class="comment">// are independent.</span> <span class="kw">let</span> <span class="ident">old_end</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">end</span>; <span class="lifetime">'search</span>: <span class="kw">loop</span> { <span class="comment">// Check that we have room to search in</span> <span class="comment">// end - needle.len() will wrap around when there is no more room,</span> <span class="comment">// but due to slice length limits it can never wrap all the way back</span> <span class="comment">// into the length of haystack.</span> <span class="kw">let</span> <span class="ident">front_byte</span> <span class="op">=</span> <span class="kw">match</span> <span class="ident">haystack</span>.<span class="ident">get</span>(<span class="self">self</span>.<span class="ident">end</span>.<span class="ident">wrapping_sub</span>(<span class="ident">needle</span>.<span class="ident">len</span>())) { <span class="prelude-val">Some</span>(<span class="kw-2">&</span><span class="ident">b</span>) <span class="op">=></span> <span class="ident">b</span>, <span class="prelude-val">None</span> <span class="op">=></span> { <span class="self">self</span>.<span class="ident">end</span> <span class="op">=</span> <span class="number">0</span>; <span class="kw">return</span> <span class="ident">S</span>::<span class="ident">rejecting</span>(<span class="number">0</span>, <span class="ident">old_end</span>); } }; <span class="kw">if</span> <span class="ident">S</span>::<span class="ident">use_early_reject</span>() <span class="op">&&</span> <span class="ident">old_end</span> <span class="op">!=</span> <span class="self">self</span>.<span class="ident">end</span> { <span class="kw">return</span> <span class="ident">S</span>::<span class="ident">rejecting</span>(<span class="self">self</span>.<span class="ident">end</span>, <span class="ident">old_end</span>); } <span class="comment">// Quickly skip by large portions unrelated to our substring</span> <span class="kw">if</span> <span class="op">!</span><span class="self">self</span>.<span class="ident">byteset_contains</span>(<span class="ident">front_byte</span>) { <span class="self">self</span>.<span class="ident">end</span> <span class="op">-=</span> <span class="ident">needle</span>.<span class="ident">len</span>(); <span class="kw">if</span> <span class="op">!</span><span class="ident">long_period</span> { <span class="self">self</span>.<span class="ident">memory_back</span> <span class="op">=</span> <span class="ident">needle</span>.<span class="ident">len</span>(); } <span class="kw">continue</span> <span class="lifetime">'search</span>; } <span class="comment">// See if the left part of the needle matches</span> <span class="kw">let</span> <span class="ident">crit</span> <span class="op">=</span> <span class="kw">if</span> <span class="ident">long_period</span> { <span class="self">self</span>.<span class="ident">crit_pos_back</span> } <span class="kw">else</span> { <span class="ident">cmp</span>::<span class="ident">min</span>(<span class="self">self</span>.<span class="ident">crit_pos_back</span>, <span class="self">self</span>.<span class="ident">memory_back</span>) }; <span class="kw">for</span> <span class="ident">i</span> <span class="kw">in</span> (<span class="number">0</span>..<span class="ident">crit</span>).<span class="ident">rev</span>() { <span class="kw">if</span> <span class="ident">needle</span>[<span class="ident">i</span>] <span class="op">!=</span> <span class="ident">haystack</span>[<span class="self">self</span>.<span class="ident">end</span> <span class="op">-</span> <span class="ident">needle</span>.<span class="ident">len</span>() <span class="op">+</span> <span class="ident">i</span>] { <span class="self">self</span>.<span class="ident">end</span> <span class="op">-=</span> <span class="self">self</span>.<span class="ident">crit_pos_back</span> <span class="op">-</span> <span class="ident">i</span>; <span class="kw">if</span> <span class="op">!</span><span class="ident">long_period</span> { <span class="self">self</span>.<span class="ident">memory_back</span> <span class="op">=</span> <span class="ident">needle</span>.<span class="ident">len</span>(); } <span class="kw">continue</span> <span class="lifetime">'search</span>; } } <span class="comment">// See if the right part of the needle matches</span> <span class="kw">let</span> <span class="ident">needle_end</span> <span class="op">=</span> <span class="kw">if</span> <span class="ident">long_period</span> { <span class="ident">needle</span>.<span class="ident">len</span>() } <span class="kw">else</span> { <span class="self">self</span>.<span class="ident">memory_back</span> }; <span class="kw">for</span> <span class="ident">i</span> <span class="kw">in</span> <span class="self">self</span>.<span class="ident">crit_pos_back</span>..<span class="ident">needle_end</span> { <span class="kw">if</span> <span class="ident">needle</span>[<span class="ident">i</span>] <span class="op">!=</span> <span class="ident">haystack</span>[<span class="self">self</span>.<span class="ident">end</span> <span class="op">-</span> <span class="ident">needle</span>.<span class="ident">len</span>() <span class="op">+</span> <span class="ident">i</span>] { <span class="self">self</span>.<span class="ident">end</span> <span class="op">-=</span> <span class="self">self</span>.<span class="ident">period</span>; <span class="kw">if</span> <span class="op">!</span><span class="ident">long_period</span> { <span class="self">self</span>.<span class="ident">memory_back</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">period</span>; } <span class="kw">continue</span> <span class="lifetime">'search</span>; } } <span class="comment">// We have found a match!</span> <span class="kw">let</span> <span class="ident">match_pos</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">end</span> <span class="op">-</span> <span class="ident">needle</span>.<span class="ident">len</span>(); <span class="comment">// Note: sub self.period instead of needle.len() to have overlapping matches</span> <span class="self">self</span>.<span class="ident">end</span> <span class="op">-=</span> <span class="ident">needle</span>.<span class="ident">len</span>(); <span class="kw">if</span> <span class="op">!</span><span class="ident">long_period</span> { <span class="self">self</span>.<span class="ident">memory_back</span> <span class="op">=</span> <span class="ident">needle</span>.<span class="ident">len</span>(); } <span class="kw">return</span> <span class="ident">S</span>::<span class="ident">matching</span>(<span class="ident">match_pos</span>, <span class="ident">match_pos</span> <span class="op">+</span> <span class="ident">needle</span>.<span class="ident">len</span>()); } } <span class="comment">// Compute the maximal suffix of `arr`.</span> <span class="comment">//</span> <span class="comment">// The maximal suffix is a possible critical factorization (u, v) of `arr`.</span> <span class="comment">//</span> <span class="comment">// Returns (`i`, `p`) where `i` is the starting index of v and `p` is the</span> <span class="comment">// period of v.</span> <span class="comment">//</span> <span class="comment">// `order_greater` determines if lexical order is `<` or `>`. Both</span> <span class="comment">// orders must be computed -- the ordering with the largest `i` gives</span> <span class="comment">// a critical factorization.</span> <span class="comment">//</span> <span class="comment">// For long period cases, the resulting period is not exact (it is too short).</span> <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">maximal_suffix</span>(<span class="ident">arr</span>: <span class="kw-2">&</span>[<span class="ident">u8</span>], <span class="ident">order_greater</span>: <span class="ident">bool</span>) <span class="op">-></span> (<span class="ident">usize</span>, <span class="ident">usize</span>) { <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">left</span> <span class="op">=</span> <span class="number">0</span>; <span class="comment">// Corresponds to i in the paper</span> <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">right</span> <span class="op">=</span> <span class="number">1</span>; <span class="comment">// Corresponds to j in the paper</span> <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">offset</span> <span class="op">=</span> <span class="number">0</span>; <span class="comment">// Corresponds to k in the paper, but starting at 0</span> <span class="comment">// to match 0-based indexing.</span> <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">period</span> <span class="op">=</span> <span class="number">1</span>; <span class="comment">// Corresponds to p in the paper</span> <span class="kw">while</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="kw-2">&</span><span class="ident">a</span>) <span class="op">=</span> <span class="ident">arr</span>.<span class="ident">get</span>(<span class="ident">right</span> <span class="op">+</span> <span class="ident">offset</span>) { <span class="comment">// `left` will be inbounds when `right` is.</span> <span class="kw">let</span> <span class="ident">b</span> <span class="op">=</span> <span class="ident">arr</span>[<span class="ident">left</span> <span class="op">+</span> <span class="ident">offset</span>]; <span class="kw">if</span> (<span class="ident">a</span> <span class="op"><</span> <span class="ident">b</span> <span class="op">&&</span> <span class="op">!</span><span class="ident">order_greater</span>) <span class="op">||</span> (<span class="ident">a</span> <span class="op">></span> <span class="ident">b</span> <span class="op">&&</span> <span class="ident">order_greater</span>) { <span class="comment">// Suffix is smaller, period is entire prefix so far.</span> <span class="ident">right</span> <span class="op">+=</span> <span class="ident">offset</span> <span class="op">+</span> <span class="number">1</span>; <span class="ident">offset</span> <span class="op">=</span> <span class="number">0</span>; <span class="ident">period</span> <span class="op">=</span> <span class="ident">right</span> <span class="op">-</span> <span class="ident">left</span>; } <span class="kw">else</span> <span class="kw">if</span> <span class="ident">a</span> <span class="op">==</span> <span class="ident">b</span> { <span class="comment">// Advance through repetition of the current period.</span> <span class="kw">if</span> <span class="ident">offset</span> <span class="op">+</span> <span class="number">1</span> <span class="op">==</span> <span class="ident">period</span> { <span class="ident">right</span> <span class="op">+=</span> <span class="ident">offset</span> <span class="op">+</span> <span class="number">1</span>; <span class="ident">offset</span> <span class="op">=</span> <span class="number">0</span>; } <span class="kw">else</span> { <span class="ident">offset</span> <span class="op">+=</span> <span class="number">1</span>; } } <span class="kw">else</span> { <span class="comment">// Suffix is larger, start over from current location.</span> <span class="ident">left</span> <span class="op">=</span> <span class="ident">right</span>; <span class="ident">right</span> <span class="op">+=</span> <span class="number">1</span>; <span class="ident">offset</span> <span class="op">=</span> <span class="number">0</span>; <span class="ident">period</span> <span class="op">=</span> <span class="number">1</span>; } } (<span class="ident">left</span>, <span class="ident">period</span>) } <span class="comment">// Compute the maximal suffix of the reverse of `arr`.</span> <span class="comment">//</span> <span class="comment">// The maximal suffix is a possible critical factorization (u', v') of `arr`.</span> <span class="comment">//</span> <span class="comment">// Returns `i` where `i` is the starting index of v', from the back;</span> <span class="comment">// returns immediately when a period of `known_period` is reached.</span> <span class="comment">//</span> <span class="comment">// `order_greater` determines if lexical order is `<` or `>`. Both</span> <span class="comment">// orders must be computed -- the ordering with the largest `i` gives</span> <span class="comment">// a critical factorization.</span> <span class="comment">//</span> <span class="comment">// For long period cases, the resulting period is not exact (it is too short).</span> <span class="kw">fn</span> <span class="ident">reverse_maximal_suffix</span>(<span class="ident">arr</span>: <span class="kw-2">&</span>[<span class="ident">u8</span>], <span class="ident">known_period</span>: <span class="ident">usize</span>, <span class="ident">order_greater</span>: <span class="ident">bool</span>) <span class="op">-></span> <span class="ident">usize</span> { <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">left</span> <span class="op">=</span> <span class="number">0</span>; <span class="comment">// Corresponds to i in the paper</span> <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">right</span> <span class="op">=</span> <span class="number">1</span>; <span class="comment">// Corresponds to j in the paper</span> <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">offset</span> <span class="op">=</span> <span class="number">0</span>; <span class="comment">// Corresponds to k in the paper, but starting at 0</span> <span class="comment">// to match 0-based indexing.</span> <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">period</span> <span class="op">=</span> <span class="number">1</span>; <span class="comment">// Corresponds to p in the paper</span> <span class="kw">let</span> <span class="ident">n</span> <span class="op">=</span> <span class="ident">arr</span>.<span class="ident">len</span>(); <span class="kw">while</span> <span class="ident">right</span> <span class="op">+</span> <span class="ident">offset</span> <span class="op"><</span> <span class="ident">n</span> { <span class="kw">let</span> <span class="ident">a</span> <span class="op">=</span> <span class="ident">arr</span>[<span class="ident">n</span> <span class="op">-</span> (<span class="number">1</span> <span class="op">+</span> <span class="ident">right</span> <span class="op">+</span> <span class="ident">offset</span>)]; <span class="kw">let</span> <span class="ident">b</span> <span class="op">=</span> <span class="ident">arr</span>[<span class="ident">n</span> <span class="op">-</span> (<span class="number">1</span> <span class="op">+</span> <span class="ident">left</span> <span class="op">+</span> <span class="ident">offset</span>)]; <span class="kw">if</span> (<span class="ident">a</span> <span class="op"><</span> <span class="ident">b</span> <span class="op">&&</span> <span class="op">!</span><span class="ident">order_greater</span>) <span class="op">||</span> (<span class="ident">a</span> <span class="op">></span> <span class="ident">b</span> <span class="op">&&</span> <span class="ident">order_greater</span>) { <span class="comment">// Suffix is smaller, period is entire prefix so far.</span> <span class="ident">right</span> <span class="op">+=</span> <span class="ident">offset</span> <span class="op">+</span> <span class="number">1</span>; <span class="ident">offset</span> <span class="op">=</span> <span class="number">0</span>; <span class="ident">period</span> <span class="op">=</span> <span class="ident">right</span> <span class="op">-</span> <span class="ident">left</span>; } <span class="kw">else</span> <span class="kw">if</span> <span class="ident">a</span> <span class="op">==</span> <span class="ident">b</span> { <span class="comment">// Advance through repetition of the current period.</span> <span class="kw">if</span> <span class="ident">offset</span> <span class="op">+</span> <span class="number">1</span> <span class="op">==</span> <span class="ident">period</span> { <span class="ident">right</span> <span class="op">+=</span> <span class="ident">offset</span> <span class="op">+</span> <span class="number">1</span>; <span class="ident">offset</span> <span class="op">=</span> <span class="number">0</span>; } <span class="kw">else</span> { <span class="ident">offset</span> <span class="op">+=</span> <span class="number">1</span>; } } <span class="kw">else</span> { <span class="comment">// Suffix is larger, start over from current location.</span> <span class="ident">left</span> <span class="op">=</span> <span class="ident">right</span>; <span class="ident">right</span> <span class="op">+=</span> <span class="number">1</span>; <span class="ident">offset</span> <span class="op">=</span> <span class="number">0</span>; <span class="ident">period</span> <span class="op">=</span> <span class="number">1</span>; } <span class="kw">if</span> <span class="ident">period</span> <span class="op">==</span> <span class="ident">known_period</span> { <span class="kw">break</span>; } } <span class="macro">debug_assert</span><span class="macro">!</span>(<span class="ident">period</span> <span class="op"><=</span> <span class="ident">known_period</span>); <span class="ident">left</span> } } <span class="comment">// TwoWayStrategy allows the algorithm to either skip non-matches as quickly</span> <span class="comment">// as possible, or to work in a mode where it emits Rejects relatively quickly.</span> <span class="kw">trait</span> <span class="ident">TwoWayStrategy</span> { <span class="kw">type</span> <span class="ident">Output</span>; <span class="kw">fn</span> <span class="ident">use_early_reject</span>() <span class="op">-></span> <span class="ident">bool</span>; <span class="kw">fn</span> <span class="ident">rejecting</span>(<span class="ident">a</span>: <span class="ident">usize</span>, <span class="ident">b</span>: <span class="ident">usize</span>) <span class="op">-></span> <span class="self">Self</span>::<span class="ident">Output</span>; <span class="kw">fn</span> <span class="ident">matching</span>(<span class="ident">a</span>: <span class="ident">usize</span>, <span class="ident">b</span>: <span class="ident">usize</span>) <span class="op">-></span> <span class="self">Self</span>::<span class="ident">Output</span>; } <span class="doccomment">/// Skip to match intervals as quickly as possible</span> <span class="kw">enum</span> <span class="ident">MatchOnly</span> { } <span class="kw">impl</span> <span class="ident">TwoWayStrategy</span> <span class="kw">for</span> <span class="ident">MatchOnly</span> { <span class="kw">type</span> <span class="ident">Output</span> <span class="op">=</span> <span class="prelude-ty">Option</span><span class="op"><</span>(<span class="ident">usize</span>, <span class="ident">usize</span>)<span class="op">></span>; <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">use_early_reject</span>() <span class="op">-></span> <span class="ident">bool</span> { <span class="bool-val">false</span> } <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">rejecting</span>(<span class="ident">_a</span>: <span class="ident">usize</span>, <span class="ident">_b</span>: <span class="ident">usize</span>) <span class="op">-></span> <span class="self">Self</span>::<span class="ident">Output</span> { <span class="prelude-val">None</span> } <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">matching</span>(<span class="ident">a</span>: <span class="ident">usize</span>, <span class="ident">b</span>: <span class="ident">usize</span>) <span class="op">-></span> <span class="self">Self</span>::<span class="ident">Output</span> { <span class="prelude-val">Some</span>((<span class="ident">a</span>, <span class="ident">b</span>)) } } <span class="doccomment">/// Emit Rejects regularly</span> <span class="kw">enum</span> <span class="ident">RejectAndMatch</span> { } <span class="kw">impl</span> <span class="ident">TwoWayStrategy</span> <span class="kw">for</span> <span class="ident">RejectAndMatch</span> { <span class="kw">type</span> <span class="ident">Output</span> <span class="op">=</span> <span class="ident">SearchStep</span>; <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">use_early_reject</span>() <span class="op">-></span> <span class="ident">bool</span> { <span class="bool-val">true</span> } <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">rejecting</span>(<span class="ident">a</span>: <span class="ident">usize</span>, <span class="ident">b</span>: <span class="ident">usize</span>) <span class="op">-></span> <span class="self">Self</span>::<span class="ident">Output</span> { <span class="ident">SearchStep</span>::<span class="ident">Reject</span>(<span class="ident">a</span>, <span class="ident">b</span>) } <span class="attribute">#[<span class="ident">inline</span>]</span> <span class="kw">fn</span> <span class="ident">matching</span>(<span class="ident">a</span>: <span class="ident">usize</span>, <span class="ident">b</span>: <span class="ident">usize</span>) <span class="op">-></span> <span class="self">Self</span>::<span class="ident">Output</span> { <span class="ident">SearchStep</span>::<span class="ident">Match</span>(<span class="ident">a</span>, <span class="ident">b</span>) } } </pre> </section><section id="search" class="content hidden"></section><section class="footer"></section><aside id="help" class="hidden"><div><h1 class="hidden">Help</h1><div class="shortcuts"><h2>Keyboard Shortcuts</h2><dl><dt><kbd>?</kbd></dt><dd>Show this help dialog</dd><dt><kbd>S</kbd></dt><dd>Focus the search field</dd><dt><kbd>↑</kbd></dt><dd>Move up in search results</dd><dt><kbd>↓</kbd></dt><dd>Move down in search results</dd><dt><kbd>↹</kbd></dt><dd>Switch tab</dd><dt><kbd>⏎</kbd></dt><dd>Go to active search result</dd><dt><kbd>+</kbd></dt><dd>Expand all sections</dd><dt><kbd>-</kbd></dt><dd>Collapse all sections</dd></dl></div><div class="infos"><h2>Search Tricks</h2><p>Prefix searches with a type followed by a colon (e.g. <code>fn:</code>) to restrict the search to a given type.</p><p>Accepted types are: <code>fn</code>, <code>mod</code>, <code>struct</code>, <code>enum</code>, <code>trait</code>, <code>type</code>, <code>macro</code>, and <code>const</code>.</p><p>Search functions by type signature (e.g. <code>vec -> usize</code> or <code>* -> vec</code>)</p><p>Search multiple things at once by splitting your query with comma (e.g. <code>str,u8</code> or <code>String,struct:Vec,test</code>)</p></div></div></aside><script>window.rootPath = "../../../";window.currentCrate = "core";</script><script src="../../../aliases.js"></script><script src="../../../main.js"></script><script defer src="../../../search-index.js"></script></body></html>