ClickHouse/contrib/libzlib-ng/uncompr.c
2017-01-08 21:26:03 +03:00

76 lines
2.5 KiB
C

/* uncompr.c -- decompress a memory buffer
* Copyright (C) 1995-2003, 2010, 2014 Jean-loup Gailly, Mark Adler.
* For conditions of distribution and use, see copyright notice in zlib.h
*/
/* @(#) $Id$ */
#define ZLIB_INTERNAL
#include "zlib.h"
/* ===========================================================================
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.
uncompress 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, including if the
input data is an incomplete zlib stream.
*/
int ZEXPORT uncompress(unsigned char *dest, size_t *destLen, const unsigned char *source, size_t sourceLen) {
z_stream stream;
int err;
const unsigned int max = (unsigned int)0 - 1;
size_t left;
unsigned char buf[1]; /* for detection of incomplete stream when *destLen == 0 */
if (*destLen) {
left = *destLen;
*destLen = 0;
}
else {
left = 1;
dest = buf;
}
stream.next_in = (const unsigned char *)source;
stream.avail_in = 0;
stream.zalloc = (alloc_func)0;
stream.zfree = (free_func)0;
stream.opaque = NULL;
err = inflateInit(&stream);
if (err != Z_OK) return err;
stream.next_out = dest;
stream.avail_out = 0;
do {
if (stream.avail_out == 0) {
stream.avail_out = left > (unsigned long)max ? max : (unsigned int)left;
left -= stream.avail_out;
}
if (stream.avail_in == 0) {
stream.avail_in = sourceLen > (unsigned long)max ? max : (unsigned int)sourceLen;
sourceLen -= stream.avail_in;
}
err = inflate(&stream, Z_NO_FLUSH);
} while (err == Z_OK);
if (dest != buf)
*destLen = stream.total_out;
else if (stream.total_out && err == Z_BUF_ERROR)
left = 1;
inflateEnd(&stream);
return err == Z_STREAM_END ? Z_OK :
err == Z_NEED_DICT ? Z_DATA_ERROR :
err == Z_BUF_ERROR && left + stream.avail_out ? Z_DATA_ERROR :
err;
}