头文件：
#include "zlib.h"
编译：
需要加上 -lz
解压缩：
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#define CHUNK 100000
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int decodeZip(char *source,int len,char **dest)
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{
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int ret;
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unsigned have;
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z_stream strm;
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unsigned char out[CHUNK];
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int totalsize = 0;
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/* allocate inflate state */
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strm.zalloc = Z_NULL;
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strm.zfree = Z_NULL;
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strm.opaque = Z_NULL;
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strm.avail_in = 0;
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strm.next_in = Z_NULL;
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ret = inflateInit2(&strm, 31);
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if (ret != Z_OK)
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return ret;
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strm.avail_in = len;
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strm.next_in = (unsigned char*)source;
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/* run inflate() on input until output
buffer not full */
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do {
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strm.avail_out = CHUNK;
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strm.next_out = out;
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ret = inflate(&strm, Z_NO_FLUSH);
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switch (ret)
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{
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case Z_NEED_DICT:
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ret = Z_DATA_ERROR; /* and fall
through */
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case Z_DATA_ERROR:
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case Z_MEM_ERROR:
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inflateEnd(&strm);
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return ret;
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}
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have = CHUNK - strm.avail_out;
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totalsize += have;
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*dest = (char*)realloc(*dest,totalsize);
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memcpy(*dest + totalsize - have,out,have);
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} while (strm.avail_out == 0);
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/* clean up and return */
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inflateEnd(&strm);
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return ret == Z_STREAM_END ? Z_OK : Z_DATA_ERROR;
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}
压缩：
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#define MaxLen 10000000
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/**
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* 对内容进行压缩和编码工作
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*/
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void encodeZip(const string &buffer, string& zipBuf, int& zipLen)
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{
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unsigned char _zipSrc[MaxLen];
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unsigned char _zipDst[MaxLen];
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unsigned char _scBuffer[MaxLen];
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//先对原始内容进行压缩工作
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unsigned int tmpLen = buffer.length();
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memcpy(_zipSrc, buffer.c_str(), tmpLen);
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z_stream c_stream;
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c_stream.zalloc = (alloc_func)0;
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c_stream.zfree = (free_func)0;
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c_stream.opaque = (voidpf)0;
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c_stream.next_in = (Bytef*)_zipSrc;
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c_stream.avail_in = tmpLen;
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c_stream.next_out = (Bytef*)_zipDst;
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c_stream.avail_out = (unsigned int)MaxLen;
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int ret = deflateInit2(&c_stream, Z_DEFAULT_COMPRESSION,Z_DEFLATED, 31,8, Z_DEFAULT_STRATEGY);
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if(ret != Z_OK)
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{
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cout <<"|"<<"deflateInit2
error "<<endl;
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return;
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}
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ret = deflate(&c_stream, Z_FINISH);
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if (ret != Z_STREAM_END)
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{
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deflateEnd(&c_stream);
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cout <<"|"<<"ret
!= Z_STREAM_END err="<< ret <<endl;
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return;
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}
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zipLen = c_stream.total_out;
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ret = deflateEnd(&c_stream);
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if (ret != Z_OK)
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{
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cout <<"|"<<"deflateEnd
error "<<endl;
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return;
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}
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//压缩完毕进行返回包组织
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memcpy(_scBuffer, _zipDst, zipLen);
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zipBuf = string(_scBuffer, zipLen);
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return;
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}
使用ZLib库压缩解压缩Demo
原文：http://blog.csdn.net/ghevinn/article/details/45747485
