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<h1>apr_hash.h</h1><a href="apr__hash_8h.html">Go to the documentation of this file.</a><div class="fragment"><pre class="fragment">00001 <span class="comment">/* Copyright 2000-2004 The Apache Software Foundation</span>
00002 <span class="comment"> *</span>
00003 <span class="comment"> * Licensed under the Apache License, Version 2.0 (the "License");</span>
00004 <span class="comment"> * you may not use this file except in compliance with the License.</span>
00005 <span class="comment"> * You may obtain a copy of the License at</span>
00006 <span class="comment"> *</span>
00007 <span class="comment"> * http://www.apache.org/licenses/LICENSE-2.0</span>
00008 <span class="comment"> *</span>
00009 <span class="comment"> * Unless required by applicable law or agreed to in writing, software</span>
00010 <span class="comment"> * distributed under the License is distributed on an "AS IS" BASIS,</span>
00011 <span class="comment"> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.</span>
00012 <span class="comment"> * See the License for the specific language governing permissions and</span>
00013 <span class="comment"> * limitations under the License.</span>
00014 <span class="comment"> */</span>
00015
00016 <span class="preprocessor">#ifndef APR_HASH_H</span>
00017 <span class="preprocessor"></span><span class="preprocessor">#define APR_HASH_H</span>
00018 <span class="preprocessor"></span><span class="comment"></span>
00019 <span class="comment">/**</span>
00020 <span class="comment"> * @file apr_hash.h</span>
00021 <span class="comment"> * @brief APR Hash Tables</span>
00022 <span class="comment"> */</span>
00023
00024 <span class="preprocessor">#include "<a class="code" href="apr__pools_8h.html">apr_pools.h</a>"</span>
00025
00026 <span class="preprocessor">#ifdef __cplusplus</span>
00027 <span class="preprocessor"></span><span class="keyword">extern</span> <span class="stringliteral">"C"</span> {
00028 <span class="preprocessor">#endif</span>
00029 <span class="preprocessor"></span><span class="comment"></span>
00030 <span class="comment">/**</span>
00031 <span class="comment"> * @defgroup apr_hash Hash Tables</span>
00032 <span class="comment"> * @ingroup APR </span>
00033 <span class="comment"> * @{</span>
00034 <span class="comment"> */</span>
00035 <span class="comment"></span>
00036 <span class="comment">/**</span>
00037 <span class="comment"> * When passing a key to apr_hash_set or apr_hash_get, this value can be</span>
00038 <span class="comment"> * passed to indicate a string-valued key, and have apr_hash compute the</span>
00039 <span class="comment"> * length automatically.</span>
00040 <span class="comment"> *</span>
00041 <span class="comment"> * @remark apr_hash will use strlen(key) for the length. The NUL terminator</span>
00042 <span class="comment"> * is not included in the hash value (why throw a constant in?).</span>
00043 <span class="comment"> * Since the hash table merely references the provided key (rather</span>
00044 <span class="comment"> * than copying it), apr_hash_this() will return the NUL-term'd key.</span>
00045 <span class="comment"> */</span>
<a name="l00046"></a><a class="code" href="group__apr__hash.html#ga16">00046</a> <span class="preprocessor">#define APR_HASH_KEY_STRING (-1)</span>
00047 <span class="preprocessor"></span><span class="comment"></span>
00048 <span class="comment">/**</span>
00049 <span class="comment"> * Abstract type for hash tables.</span>
00050 <span class="comment"> */</span>
<a name="l00051"></a><a class="code" href="group__apr__hash.html#ga0">00051</a> <span class="keyword">typedef</span> <span class="keyword">struct </span><a class="code" href="group__apr__hash.html#ga0">apr_hash_t</a> <a class="code" href="group__apr__hash.html#ga0">apr_hash_t</a>;
00052 <span class="comment"></span>
00053 <span class="comment">/**</span>
00054 <span class="comment"> * Abstract type for scanning hash tables.</span>
00055 <span class="comment"> */</span>
<a name="l00056"></a><a class="code" href="group__apr__hash.html#ga1">00056</a> <span class="keyword">typedef</span> <span class="keyword">struct </span><a class="code" href="group__apr__hash.html#ga1">apr_hash_index_t</a> <a class="code" href="group__apr__hash.html#ga1">apr_hash_index_t</a>;
00057 <span class="comment"></span>
00058 <span class="comment">/**</span>
00059 <span class="comment"> * Callback functions for calculating hash values.</span>
00060 <span class="comment"> * @param key The key.</span>
00061 <span class="comment"> * @param klen The length of the key, or APR_HASH_KEY_STRING to use the string </span>
00062 <span class="comment"> * length. If APR_HASH_KEY_STRING then returns the actual key length.</span>
00063 <span class="comment"> */</span>
<a name="l00064"></a><a class="code" href="group__apr__hash.html#ga2">00064</a> <span class="keyword">typedef</span> <span class="keywordtype">unsigned</span> int (*apr_hashfunc_t)(<span class="keyword">const</span> <span class="keywordtype">char</span> *key, apr_ssize_t *klen);
00065 <span class="comment"></span>
00066 <span class="comment">/**</span>
00067 <span class="comment"> * The default hash function.</span>
00068 <span class="comment"> */</span>
00069 <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> <a class="code" href="group__apr__hash.html#ga3">apr_hashfunc_default</a>(<span class="keyword">const</span> <span class="keywordtype">char</span> *key, apr_ssize_t *klen);
00070 <span class="comment"></span>
00071 <span class="comment">/**</span>
00072 <span class="comment"> * Create a hash table.</span>
00073 <span class="comment"> * @param pool The pool to allocate the hash table out of</span>
00074 <span class="comment"> * @return The hash table just created</span>
00075 <span class="comment"> */</span>
00076 <a class="code" href="group__apr__platform.html#ga123">APR_DECLARE</a>(apr_hash_t *) apr_hash_make(apr_pool_t *pool);
00077 <span class="comment"></span>
00078 <span class="comment">/**</span>
00079 <span class="comment"> * Create a hash table with a custom hash function</span>
00080 <span class="comment"> * @param pool The pool to allocate the hash table out of</span>
00081 <span class="comment"> * @param hash_func A custom hash function.</span>
00082 <span class="comment"> * @return The hash table just created</span>
00083 <span class="comment"> */</span>
00084 APR_DECLARE(apr_hash_t *) apr_hash_make_custom(apr_pool_t *pool,
00085 apr_hashfunc_t hash_func);
00086 <span class="comment"></span>
00087 <span class="comment">/**</span>
00088 <span class="comment"> * Make a copy of a hash table</span>
00089 <span class="comment"> * @param pool The pool from which to allocate the new hash table</span>
00090 <span class="comment"> * @param h The hash table to clone</span>
00091 <span class="comment"> * @return The hash table just created</span>
00092 <span class="comment"> * @remark Makes a shallow copy</span>
00093 <span class="comment"> */</span>
00094 APR_DECLARE(apr_hash_t *) apr_hash_copy(apr_pool_t *pool,
00095 const apr_hash_t *h);
00096 <span class="comment"></span>
00097 <span class="comment">/**</span>
00098 <span class="comment"> * Associate a value with a key in a hash table.</span>
00099 <span class="comment"> * @param ht The hash table</span>
00100 <span class="comment"> * @param key Pointer to the key</span>
00101 <span class="comment"> * @param klen Length of the key. Can be APR_HASH_KEY_STRING to use the string length.</span>
00102 <span class="comment"> * @param val Value to associate with the key</span>
00103 <span class="comment"> * @remark If the value is NULL the hash entry is deleted.</span>
00104 <span class="comment"> */</span>
00105 APR_DECLARE(<span class="keywordtype">void</span>) apr_hash_set(apr_hash_t *ht, const <span class="keywordtype">void</span> *key,
00106 apr_ssize_t klen, const <span class="keywordtype">void</span> *val);
00107 <span class="comment"></span>
00108 <span class="comment">/**</span>
00109 <span class="comment"> * Look up the value associated with a key in a hash table.</span>
00110 <span class="comment"> * @param ht The hash table</span>
00111 <span class="comment"> * @param key Pointer to the key</span>
00112 <span class="comment"> * @param klen Length of the key. Can be APR_HASH_KEY_STRING to use the string length.</span>
00113 <span class="comment"> * @return Returns NULL if the key is not present.</span>
00114 <span class="comment"> */</span>
00115 APR_DECLARE(<span class="keywordtype">void</span> *) apr_hash_get(apr_hash_t *ht, const <span class="keywordtype">void</span> *key,
00116 apr_ssize_t klen);
00117 <span class="comment"></span>
00118 <span class="comment">/**</span>
00119 <span class="comment"> * Start iterating over the entries in a hash table.</span>
00120 <span class="comment"> * @param p The pool to allocate the apr_hash_index_t iterator. If this</span>
00121 <span class="comment"> * pool is NULL, then an internal, non-thread-safe iterator is used.</span>
00122 <span class="comment"> * @param ht The hash table</span>
00123 <span class="comment"> * @remark There is no restriction on adding or deleting hash entries during</span>
00124 <span class="comment"> * an iteration (although the results may be unpredictable unless all you do</span>
00125 <span class="comment"> * is delete the current entry) and multiple iterations can be in</span>
00126 <span class="comment"> * progress at the same time.</span>
00127 <span class="comment"></span>
00128 <span class="comment"> * @example</span>
00129 <span class="comment"> */</span><span class="comment"></span>
00130 <span class="comment">/**</span>
00131 <span class="comment"> * <PRE></span>
00132 <span class="comment"> * </span>
00133 <span class="comment"> * int sum_values(apr_pool_t *p, apr_hash_t *ht)</span>
00134 <span class="comment"> * {</span>
00135 <span class="comment"> * apr_hash_index_t *hi;</span>
00136 <span class="comment"> * void *val;</span>
00137 <span class="comment"> * int sum = 0;</span>
00138 <span class="comment"> * for (hi = apr_hash_first(p, ht); hi; hi = apr_hash_next(hi)) {</span>
00139 <span class="comment"> * apr_hash_this(hi, NULL, NULL, &val);</span>
00140 <span class="comment"> * sum += *(int *)val;</span>
00141 <span class="comment"> * }</span>
00142 <span class="comment"> * return sum;</span>
00143 <span class="comment"> * }</span>
00144 <span class="comment"> * </PRE></span>
00145 <span class="comment"> */</span>
00146 APR_DECLARE(apr_hash_index_t *) apr_hash_first(apr_pool_t *p, apr_hash_t *ht);
00147 <span class="comment"></span>
00148 <span class="comment">/**</span>
00149 <span class="comment"> * Continue iterating over the entries in a hash table.</span>
00150 <span class="comment"> * @param hi The iteration state</span>
00151 <span class="comment"> * @return a pointer to the updated iteration state. NULL if there are no more </span>
00152 <span class="comment"> * entries.</span>
00153 <span class="comment"> */</span>
00154 APR_DECLARE(apr_hash_index_t *) apr_hash_next(apr_hash_index_t *hi);
00155 <span class="comment"></span>
00156 <span class="comment">/**</span>
00157 <span class="comment"> * Get the current entry's details from the iteration state.</span>
00158 <span class="comment"> * @param hi The iteration state</span>
00159 <span class="comment"> * @param key Return pointer for the pointer to the key.</span>
00160 <span class="comment"> * @param klen Return pointer for the key length.</span>
00161 <span class="comment"> * @param val Return pointer for the associated value.</span>
00162 <span class="comment"> * @remark The return pointers should point to a variable that will be set to the</span>
00163 <span class="comment"> * corresponding data, or they may be NULL if the data isn't interesting.</span>
00164 <span class="comment"> */</span>
00165 APR_DECLARE(<span class="keywordtype">void</span>) apr_hash_this(apr_hash_index_t *hi, const <span class="keywordtype">void</span> **key,
00166 apr_ssize_t *klen, <span class="keywordtype">void</span> **val);
00167 <span class="comment"></span>
00168 <span class="comment">/**</span>
00169 <span class="comment"> * Get the number of key/value pairs in the hash table.</span>
00170 <span class="comment"> * @param ht The hash table</span>
00171 <span class="comment"> * @return The number of key/value pairs in the hash table.</span>
00172 <span class="comment"> */</span>
00173 APR_DECLARE(<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span>) apr_hash_count(apr_hash_t *ht);
00174 <span class="comment"></span>
00175 <span class="comment">/**</span>
00176 <span class="comment"> * Merge two hash tables into one new hash table. The values of the overlay</span>
00177 <span class="comment"> * hash override the values of the base if both have the same key. Both</span>
00178 <span class="comment"> * hash tables must use the same hash function.</span>
00179 <span class="comment"> * @param p The pool to use for the new hash table</span>
00180 <span class="comment"> * @param overlay The table to add to the initial table</span>
00181 <span class="comment"> * @param base The table that represents the initial values of the new table</span>
00182 <span class="comment"> * @return A new hash table containing all of the data from the two passed in</span>
00183 <span class="comment"> */</span>
00184 APR_DECLARE(apr_hash_t *) apr_hash_overlay(apr_pool_t *p,
00185 const apr_hash_t *overlay,
00186 const apr_hash_t *base);
00187 <span class="comment"></span>
00188 <span class="comment">/**</span>
00189 <span class="comment"> * Merge two hash tables into one new hash table. If the same key</span>
00190 <span class="comment"> * is present in both tables, call the supplied merge function to</span>
00191 <span class="comment"> * produce a merged value for the key in the new table. Both</span>
00192 <span class="comment"> * hash tables must use the same hash function.</span>
00193 <span class="comment"> * @param p The pool to use for the new hash table</span>
00194 <span class="comment"> * @param h1 The first of the tables to merge</span>
00195 <span class="comment"> * @param h2 The second of the tables to merge</span>
00196 <span class="comment"> * @param merger A callback function to merge values, or NULL to</span>
00197 <span class="comment"> * make values from h1 override values from h2 (same semantics as</span>
00198 <span class="comment"> * apr_hash_overlay())</span>
00199 <span class="comment"> * @param data Client data to pass to the merger function</span>
00200 <span class="comment"> * @return A new hash table containing all of the data from the two passed in</span>
00201 <span class="comment"> */</span>
00202 APR_DECLARE(apr_hash_t *) apr_hash_merge(apr_pool_t *p,
00203 const apr_hash_t *h1,
00204 const apr_hash_t *h2,
00205 <span class="keywordtype">void</span> * (*merger)(apr_pool_t *p,
00206 const <span class="keywordtype">void</span> *key,
00207 apr_ssize_t klen,
00208 const <span class="keywordtype">void</span> *h1_val,
00209 const <span class="keywordtype">void</span> *h2_val,
00210 const <span class="keywordtype">void</span> *data),
00211 const <span class="keywordtype">void</span> *data);
00212 <span class="comment"></span>
00213 <span class="comment">/**</span>
00214 <span class="comment"> * Get a pointer to the pool which the hash table was created in</span>
00215 <span class="comment"> */</span>
00216 APR_POOL_DECLARE_ACCESSOR(hash);
00217 <span class="comment"></span>
00218 <span class="comment">/** @} */</span>
00219
00220 #ifdef __cplusplus
00221 }
00222 #endif
00223
00224 #endif <span class="comment">/* !APR_HASH_H */</span>
</pre></div><hr size="1"><address style="align: right;"><small>Generated on Sun Mar 20 19:52:26 2005 for Apache Portable Runtime by
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