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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 17:32:43 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 17:32:43 +0000 |
commit | 6bf0a5cb5034a7e684dcc3500e841785237ce2dd (patch) | |
tree | a68f146d7fa01f0134297619fbe7e33db084e0aa /media/ffvpx/libavutil/adler32.c | |
parent | Initial commit. (diff) | |
download | thunderbird-6bf0a5cb5034a7e684dcc3500e841785237ce2dd.tar.xz thunderbird-6bf0a5cb5034a7e684dcc3500e841785237ce2dd.zip |
Adding upstream version 1:115.7.0.upstream/1%115.7.0upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | media/ffvpx/libavutil/adler32.c | 96 |
1 files changed, 96 insertions, 0 deletions
diff --git a/media/ffvpx/libavutil/adler32.c b/media/ffvpx/libavutil/adler32.c new file mode 100644 index 0000000000..7124f18802 --- /dev/null +++ b/media/ffvpx/libavutil/adler32.c @@ -0,0 +1,96 @@ +/* + * Compute the Adler-32 checksum of a data stream. + * This is a modified version based on adler32.c from the zlib library. + * + * Copyright (C) 1995 Mark Adler + * + * This software is provided 'as-is', without any express or implied + * warranty. In no event will the authors be held liable for any damages + * arising from the use of this software. + * + * Permission is granted to anyone to use this software for any purpose, + * including commercial applications, and to alter it and redistribute it + * freely, subject to the following restrictions: + * + * 1. The origin of this software must not be misrepresented; you must not + * claim that you wrote the original software. If you use this software + * in a product, an acknowledgment in the product documentation would be + * appreciated but is not required. + * 2. Altered source versions must be plainly marked as such, and must not be + * misrepresented as being the original software. + * 3. This notice may not be removed or altered from any source distribution. + */ + +/** + * @file + * Computes the Adler-32 checksum of a data stream + * + * This is a modified version based on adler32.c from the zlib library. + * @author Mark Adler + * @ingroup lavu_adler32 + */ + +#include "config.h" +#include "adler32.h" +#include "intreadwrite.h" +#include "macros.h" + +#define BASE 65521L /* largest prime smaller than 65536 */ + +#define DO1(buf) { s1 += *buf++; s2 += s1; } +#define DO4(buf) DO1(buf); DO1(buf); DO1(buf); DO1(buf); +#define DO16(buf) DO4(buf); DO4(buf); DO4(buf); DO4(buf); + +AVAdler av_adler32_update(AVAdler adler, const uint8_t *buf, size_t len) +{ + unsigned long s1 = adler & 0xffff; + unsigned long s2 = adler >> 16; + + while (len > 0) { +#if HAVE_FAST_64BIT && HAVE_FAST_UNALIGNED && !CONFIG_SMALL + unsigned len2 = FFMIN((len-1) & ~7, 23*8); + if (len2) { + uint64_t a1= 0; + uint64_t a2= 0; + uint64_t b1= 0; + uint64_t b2= 0; + len -= len2; + s2 += s1*len2; + while (len2 >= 8) { + uint64_t v = AV_RN64(buf); + a2 += a1; + b2 += b1; + a1 += v &0x00FF00FF00FF00FF; + b1 += (v>>8)&0x00FF00FF00FF00FF; + len2 -= 8; + buf+=8; + } + + //We combine the 8 interleaved adler32 checksums without overflows + //Decreasing the number of iterations would allow below code to be + //simplified but would likely be slower due to the fewer iterations + //of the inner loop + s1 += ((a1+b1)*0x1000100010001)>>48; + s2 += ((((a2&0xFFFF0000FFFF)+(b2&0xFFFF0000FFFF)+((a2>>16)&0xFFFF0000FFFF)+((b2>>16)&0xFFFF0000FFFF))*0x800000008)>>32) +#if HAVE_BIGENDIAN + + 2*((b1*0x1000200030004)>>48) + + ((a1*0x1000100010001)>>48) + + 2*((a1*0x0000100020003)>>48); +#else + + 2*((a1*0x4000300020001)>>48) + + ((b1*0x1000100010001)>>48) + + 2*((b1*0x3000200010000)>>48); +#endif + } +#else + while (len > 4 && s2 < (1U << 31)) { + DO4(buf); + len -= 4; + } +#endif + DO1(buf); len--; + s1 %= BASE; + s2 %= BASE; + } + return (s2 << 16) | s1; +} |