CppUtils/Utils/zlib/compress.c

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2025-06-05 10:06:43 +08:00

#define ZLIB_INTERNAL
#include "zlib.h"
int ZEXPORT compress2 (dest, destLen, source, sourceLen, level)
Bytef *dest;
uLongf *destLen;
const Bytef *source;
uLong sourceLen;
int level;
{
z_stream stream;
int err;
const uInt max = (uInt)-1;
uLong left;
left = *destLen;
*destLen = 0;
stream.zalloc = (alloc_func)0;
stream.zfree = (free_func)0;
stream.opaque = (voidpf)0;
err = deflateInit(&stream, level);
if (err != Z_OK) return err;
stream.next_out = dest;
stream.avail_out = 0;
stream.next_in = (z_const Bytef *)source;
stream.avail_in = 0;
do {
if (stream.avail_out == 0) {
stream.avail_out = left > (uLong)max ? max : (uInt)left;
left -= stream.avail_out;
}
if (stream.avail_in == 0) {
stream.avail_in = sourceLen > (uLong)max ? max : (uInt)sourceLen;
sourceLen -= stream.avail_in;
}
err = deflate(&stream, sourceLen ? Z_NO_FLUSH : Z_FINISH);
} while (err == Z_OK);
*destLen = stream.total_out;
deflateEnd(&stream);
return err == Z_STREAM_END ? Z_OK : err;
}
int ZEXPORT compress (dest, destLen, source, sourceLen)
Bytef *dest;
uLongf *destLen;
const Bytef *source;
uLong sourceLen;
{
return compress2(dest, destLen, source, sourceLen, Z_DEFAULT_COMPRESSION);
}
uLong ZEXPORT compressBound (sourceLen)
uLong sourceLen;
{
return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) +
(sourceLen >> 25) + 13;
}