opencv/3rdparty/zlib-ng/crc32_fold.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

34 lines
1.1 KiB
C

/* crc32_fold.c -- crc32 folding interface
* Copyright (C) 2021 Nathan Moinvaziri
* For conditions of distribution and use, see copyright notice in zlib.h
*/
#include "zbuild.h"
#include "functable.h"
#include "crc32_fold.h"
#include <limits.h>
Z_INTERNAL uint32_t crc32_fold_reset_c(crc32_fold *crc) {
crc->value = CRC32_INITIAL_VALUE;
return crc->value;
}
Z_INTERNAL void crc32_fold_copy_c(crc32_fold *crc, uint8_t *dst, const uint8_t *src, size_t len) {
crc->value = functable.crc32(crc->value, src, len);
memcpy(dst, src, len);
}
Z_INTERNAL void crc32_fold_c(crc32_fold *crc, const uint8_t *src, size_t len, uint32_t init_crc) {
/* Note: while this is basically the same thing as the vanilla CRC function, we still need
* a functable entry for it so that we can generically dispatch to this function with the
* same arguments for the versions that _do_ do a folding CRC but we don't want a copy. The
* init_crc is an unused argument in this context */
Z_UNUSED(init_crc);
crc->value = functable.crc32(crc->value, src, len);
}
Z_INTERNAL uint32_t crc32_fold_final_c(crc32_fold *crc) {
return crc->value;
}