www.pudn.com > 200410111032011273DESMD5ZLIB算法源代码.rar > Compress.cpp

#include "stdafx.h" 
#include "zlib.h" 
 
/* =========================================================================== 
     Compresses the source buffer into the destination buffer. The level 
   parameter has the same meaning as in deflateInit.  sourceLen is the byte 
   length of the source buffer. Upon entry, destLen is the total size of the 
   destination buffer, which must be at least 0.1% larger than sourceLen plus 
   12 bytes. Upon exit, destLen is the actual size of the compressed buffer. 
 
     compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 
   memory, Z_BUF_ERROR if there was not enough room in the output buffer, 
   Z_STREAM_ERROR if the level parameter is invalid. 
*/ 
int compress2(BYTE *dest,   
			  unsigned long *destLen,   
			  const BYTE *source, 
			  unsigned long sourceLen, 
			  int level) 
{ 
    z_stream stream; 
    int err; 
 
    stream.next_in = (BYTE*)source; 
    stream.avail_in = (unsigned int)sourceLen; 
    stream.next_out = dest; 
    stream.avail_out = (unsigned int)*destLen; 
    if ((unsigned long)stream.avail_out != *destLen) return Z_BUF_ERROR; 
 
    stream.zalloc = (alloc_func)0; 
    stream.zfree = (free_func)0; 
    stream.opaque = (void *)0; 
 
    err = deflateInit(&stream, level); 
    if (err != Z_OK) return err; 
 
    err = deflate(&stream, Z_FINISH); 
    if (err != Z_STREAM_END) { 
        deflateEnd(&stream); 
        return err == Z_OK ? Z_BUF_ERROR : err; 
    } 
    *destLen = stream.total_out; 
 
    err = deflateEnd(&stream); 
    return err; 
} 
 
/* =========================================================================== 
 */ 
ARITHDLL_API int WINAPI compress (BYTE *dest, 
    unsigned long *destLen, 
    const BYTE *source, 
    unsigned long sourceLen) 
{ 
    return compress2(dest, destLen, source, sourceLen, Z_DEFAULT_COMPRESSION); 
} 
 
/*=========================================================================== 
     Decompresses the source buffer into the destination buffer.  sourceLen is 
   the byte length of the source buffer. Upon entry, destLen is the total 
   size of the destination buffer, which must be large enough to hold the 
   entire uncompressed data. (The size of the uncompressed data must have 
   been saved previously by the compressor and transmitted to the decompressor 
   by some mechanism outside the scope of this compression library.) 
   Upon exit, destLen is the actual size of the compressed buffer. 
     This function can be used to decompress a whole file at once if the 
   input file is mmap'ed. 
 
     unzipcompress returns Z_OK if success, Z_MEM_ERROR if there was not 
   enough memory, Z_BUF_ERROR if there was not enough room in the output 
   buffer, or Z_DATA_ERROR if the input data was corrupted. 
*/ 
ARITHDLL_API int WINAPI uncompress (BYTE *dest, unsigned long *destLen, 
            const BYTE *source, unsigned long sourceLen) 
{ 
    z_stream stream; 
    int err; 
 
    stream.next_in = (BYTE*)source; 
    stream.avail_in = (unsigned int)sourceLen; 
    /* Check for source > 64K on 16-bit machine: */ 
    if ((unsigned long)stream.avail_in != sourceLen) return Z_BUF_ERROR; 
 
    stream.next_out = dest; 
    stream.avail_out = (unsigned int)*destLen; 
    if ((unsigned long)stream.avail_out != *destLen) return Z_BUF_ERROR; 
 
    stream.zalloc = (alloc_func)0; 
    stream.zfree = (free_func)0; 
 
    err = inflateInit(&stream); 
    if (err != Z_OK) return err; 
 
    err = inflate(&stream, Z_FINISH); 
    if (err != Z_STREAM_END) 
    { 
        inflateEnd(&stream); 
        return err == Z_OK ? Z_BUF_ERROR : err; 
    } 
    *destLen = stream.total_out; 
    err = inflateEnd(&stream); 
    return err; 
}