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<hr><h1>zipcomprs.cpp</h1><div class="fragment"><pre>00001 <font class="comment">/******************************************************************************</font>
00002 <font class="comment"> * swcomprs.cpp - code for class 'ZipCompress'- a driver class that provides</font>
00003 <font class="comment"> * compression utilities. - using zlib</font>
00004 <font class="comment"> */</font>
00005
00006 <font class="preprocessor">#include <string.h></font>
00007 <font class="preprocessor">#include <string></font>
00008 <font class="preprocessor">#include <stdlib.h></font>
00009 <font class="preprocessor">#include <stdio.h></font>
00010 <font class="preprocessor">#include <zipcomprs.h></font>
00011 <font class="preprocessor">#include <zlib.h></font>
00012
00013 <font class="comment">/******************************************************************************</font>
00014 <font class="comment"> * ZipCompress Constructor - Initializes data for instance of ZipCompress</font>
00015 <font class="comment"> *</font>
00016 <font class="comment"> */</font>
00017
00018 ZipCompress::ZipCompress() : SWCompress()
00019 {
00020 <font class="comment">// fprintf(stderr, "init compress\n");</font>
00021 }
00022
00023
00024 <font class="comment">/******************************************************************************</font>
00025 <font class="comment"> * ZipCompress Destructor - Cleans up instance of ZipCompress</font>
00026 <font class="comment"> */</font>
00027
00028 ZipCompress::~ZipCompress() {
00029 }
00030
00031
00032 <font class="comment">/******************************************************************************</font>
00033 <font class="comment"> * ZipCompress::Encode - This function "encodes" the input stream into the</font>
00034 <font class="comment"> * output stream.</font>
00035 <font class="comment"> * The GetChars() and SendChars() functions are</font>
00036 <font class="comment"> * used to separate this method from the actual</font>
00037 <font class="comment"> * i/o.</font>
00038 <font class="comment"> * NOTE: must set zlen for parent class to know length of</font>
00039 <font class="comment"> * compressed buffer.</font>
00040 <font class="comment"> */</font>
00041
00042 <font class="keywordtype">void</font> ZipCompress::Encode(<font class="keywordtype">void</font>)
00043 {
00044 <font class="comment">/*</font>
00045 <font class="comment">ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen,</font>
00046 <font class="comment"> const Bytef *source, uLong sourceLen));</font>
00047 <font class="comment"> Compresses the source buffer into the destination buffer. sourceLen is</font>
00048 <font class="comment"> the byte length of the source buffer. Upon entry, destLen is the total</font>
00049 <font class="comment"> size of the destination buffer, which must be at least 0.1% larger than</font>
00050 <font class="comment"> sourceLen plus 12 bytes. Upon exit, destLen is the actual size of the</font>
00051 <font class="comment"> compressed buffer.</font>
00052 <font class="comment"> This function can be used to compress a whole file at once if the</font>
00053 <font class="comment"> input file is mmap'ed.</font>
00054 <font class="comment"> compress returns Z_OK if success, Z_MEM_ERROR if there was not</font>
00055 <font class="comment"> enough memory, Z_BUF_ERROR if there was not enough room in the output</font>
00056 <font class="comment"> buffer.</font>
00057 <font class="comment">*/</font>
00058 direct = 0; <font class="comment">// set direction needed by parent [Get|Send]Chars()</font>
00059
00060 <font class="comment">// get buffer</font>
00061 <font class="keywordtype">char</font> chunk[1024];
00062 <font class="keywordtype">char</font> *buf = (<font class="keywordtype">char</font> *)calloc(1, 1024);
00063 <font class="keywordtype">char</font> *chunkbuf = buf;
00064 <font class="keywordtype">unsigned</font> <font class="keywordtype">long</font> chunklen;
00065 <font class="keywordtype">unsigned</font> <font class="keywordtype">long</font> len = 0;
00066 <font class="keywordflow">while</font>((chunklen = GetChars(chunk, 1023))) {
00067 memcpy(chunkbuf, chunk, chunklen);
00068 len += chunklen;
00069 <font class="keywordflow">if</font> (chunklen < 1023)
00070 <font class="keywordflow">break</font>;
00071 <font class="keywordflow">else</font> buf = (<font class="keywordtype">char</font> *)realloc(buf, len + 1024);
00072 chunkbuf = buf+len;
00073 }
00074
00075
00076 zlen = (long) (len*1.001)+15;
00077 <font class="keywordtype">char</font> *zbuf = <font class="keyword">new</font> <font class="keywordtype">char</font>[zlen+1];
00078 <font class="keywordflow">if</font> (len)
00079 {
00080 <font class="comment">//printf("Doing compress\n");</font>
00081 <font class="keywordflow">if</font> (compress((Bytef*)zbuf, &zlen, (<font class="keyword">const</font> Bytef*)buf, len)!=Z_OK)
00082 {
00083 printf(<font class="stringliteral">"ERROR in compression\n"</font>);
00084 }
00085 <font class="keywordflow">else</font> {
00086 SendChars(zbuf, zlen);
00087 }
00088 }
00089 <font class="keywordflow">else</font>
00090 {
00091 fprintf(stderr, <font class="stringliteral">"No buffer to compress\n"</font>);
00092 }
00093 <font class="keyword">delete</font> [] zbuf;
00094 free (buf);
00095 }
00096
00097
00098 <font class="comment">/******************************************************************************</font>
00099 <font class="comment"> * ZipCompress::Decode - This function "decodes" the input stream into the</font>
00100 <font class="comment"> * output stream.</font>
00101 <font class="comment"> * The GetChars() and SendChars() functions are</font>
00102 <font class="comment"> * used to separate this method from the actual</font>
00103 <font class="comment"> * i/o.</font>
00104 <font class="comment"> */</font>
00105
00106 <font class="keywordtype">void</font> ZipCompress::Decode(<font class="keywordtype">void</font>)
00107 {
00108 <font class="comment">/*</font>
00109 <font class="comment">ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen,</font>
00110 <font class="comment"> const Bytef *source, uLong sourceLen));</font>
00111 <font class="comment"> Decompresses the source buffer into the destination buffer. sourceLen is</font>
00112 <font class="comment"> the byte length of the source buffer. Upon entry, destLen is the total</font>
00113 <font class="comment"> size of the destination buffer, which must be large enough to hold the</font>
00114 <font class="comment"> entire uncompressed data. (The size of the uncompressed data must have</font>
00115 <font class="comment"> been saved previously by the compressor and transmitted to the decompressor</font>
00116 <font class="comment"> by some mechanism outside the scope of this compression library.)</font>
00117 <font class="comment"> Upon exit, destLen is the actual size of the compressed buffer.</font>
00118 <font class="comment"> This function can be used to decompress a whole file at once if the</font>
00119 <font class="comment"> input file is mmap'ed.</font>
00120 <font class="comment"></font>
00121 <font class="comment"> uncompress returns Z_OK if success, Z_MEM_ERROR if there was not</font>
00122 <font class="comment"> enough memory, Z_BUF_ERROR if there was not enough room in the output</font>
00123 <font class="comment"> buffer, or Z_DATA_ERROR if the input data was corrupted.</font>
00124 <font class="comment">*/</font>
00125
00126 <font class="comment">// get buffer</font>
00127 <font class="keywordtype">char</font> chunk[1024];
00128 <font class="keywordtype">char</font> *zbuf = (<font class="keywordtype">char</font> *)calloc(1, 1024);
00129 <font class="keywordtype">char</font> *chunkbuf = zbuf;
00130 <font class="keywordtype">int</font> chunklen;
00131 <font class="keywordtype">unsigned</font> <font class="keywordtype">long</font> zlen = 0;
00132 <font class="keywordflow">while</font>((chunklen = GetChars(chunk, 1023))) {
00133 memcpy(chunkbuf, chunk, chunklen);
00134 zlen += chunklen;
00135 <font class="keywordflow">if</font> (chunklen < 1023)
00136 <font class="keywordflow">break</font>;
00137 <font class="keywordflow">else</font> zbuf = (<font class="keywordtype">char</font> *)realloc(zbuf, zlen + 1024);
00138 chunkbuf = zbuf + zlen;
00139 }
00140
00141 <font class="comment">//printf("Decoding complength{%ld} uncomp{%ld}\n", zlen, blen);</font>
00142 <font class="keywordflow">if</font> (zlen) {
00143 <font class="keywordtype">unsigned</font> <font class="keywordtype">long</font> blen = zlen*20; <font class="comment">// trust compression is less than 1000%</font>
00144 <font class="keywordtype">char</font> *buf = <font class="keyword">new</font> <font class="keywordtype">char</font>[blen];
00145 <font class="comment">//printf("Doing decompress {%s}\n", zbuf);</font>
00146 <font class="keywordflow">if</font> (uncompress((Bytef*)buf, &blen, (Bytef*)zbuf, zlen) != Z_OK) {
00147 fprintf(stderr, <font class="stringliteral">"no room in outbuffer to during decompression. see zipcomp.cpp\n"</font>);
00148 }
00149 SendChars(buf, blen);
00150 <font class="keyword">delete</font> [] buf;
00151 slen = blen;
00152 }
00153 <font class="keywordflow">else</font> {
00154 fprintf(stderr, <font class="stringliteral">"No buffer to decompress!\n"</font>);
00155 }
00156 <font class="comment">//printf("Finished decoding\n");</font>
00157 free (zbuf);
00158 }
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