opencv/3rdparty/zlib-ng/uncompr.c
Letu Ren 0de26fd78e Add zlib-ng as an alternative zlib implementation
Zlib-ng is zlib replacement with optimizations for "next generation" systems. Its optimization may benifits image library decode and encode speed such as libpng. In our tests, if using zlib-ng and libpng combination on a x86_64 machine with AVX2, the time of `imdecode` amd `imencode` will drop 20% approximately. This patch enables zlib-ng's optimization if `CV_DISABLE_OPTIMIZATION` is OFF. Since Zlib-ng can dispatch intrinsics on the fly, port work is much easier.

Related discussion: https://github.com/opencv/opencv/issues/22573
2024-01-14 14:58:47 +08:00

81 lines
2.9 KiB
C

/* uncompr.c -- decompress a memory buffer
* Copyright (C) 1995-2003, 2010, 2014, 2016 Jean-loup Gailly, Mark Adler.
* For conditions of distribution and use, see copyright notice in zlib.h
*/
#include "zbuild.h"
#include "zutil.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 size of the decompressed data and *sourceLen is the number
of source bytes consumed. Upon return, source + *sourceLen points to the
first unused input byte.
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 Z_EXPORT PREFIX(uncompress2)(unsigned char *dest, z_uintmax_t *destLen, const unsigned char *source, z_uintmax_t *sourceLen) {
PREFIX3(stream) stream;
int err;
const unsigned int max = (unsigned int)-1;
z_uintmax_t len, left;
unsigned char buf[1]; /* for detection of incomplete stream when *destLen == 0 */
len = *sourceLen;
if (*destLen) {
left = *destLen;
*destLen = 0;
} else {
left = 1;
dest = buf;
}
stream.next_in = (z_const unsigned char *)source;
stream.avail_in = 0;
stream.zalloc = NULL;
stream.zfree = NULL;
stream.opaque = NULL;
err = PREFIX(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 = len > (unsigned long)max ? max : (unsigned int)len;
len -= stream.avail_in;
}
err = PREFIX(inflate)(&stream, Z_NO_FLUSH);
} while (err == Z_OK);
*sourceLen -= len + stream.avail_in;
if (dest != buf)
*destLen = (z_size_t)stream.total_out;
else if (stream.total_out && err == Z_BUF_ERROR)
left = 1;
PREFIX(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;
}
int Z_EXPORT PREFIX(uncompress)(unsigned char *dest, z_uintmax_t *destLen, const unsigned char *source, z_uintmax_t sourceLen) {
return PREFIX(uncompress2)(dest, destLen, source, &sourceLen);
}