f73495686d
Based on a patch by James Almer <jamrial@gmail.com>. Signed-off-by: Vittorio Giovara <vittorio.giovara@gmail.com>
99 lines
2.7 KiB
C
99 lines
2.7 KiB
C
/*
|
|
* 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"
|
|
|
|
#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);
|
|
|
|
unsigned long av_adler32_update(unsigned long adler, const uint8_t * buf,
|
|
unsigned int len)
|
|
{
|
|
unsigned long s1 = adler & 0xffff;
|
|
unsigned long s2 = adler >> 16;
|
|
|
|
while (len > 0) {
|
|
#if CONFIG_SMALL
|
|
while (len > 4 && s2 < (1U << 31)) {
|
|
DO4(buf);
|
|
len -= 4;
|
|
}
|
|
#else
|
|
while (len > 16 && s2 < (1U << 31)) {
|
|
DO16(buf);
|
|
len -= 16;
|
|
}
|
|
#endif
|
|
DO1(buf); len--;
|
|
s1 %= BASE;
|
|
s2 %= BASE;
|
|
}
|
|
return (s2 << 16) | s1;
|
|
}
|
|
|
|
#ifdef TEST
|
|
#include <string.h>
|
|
#include "log.h"
|
|
#include "timer.h"
|
|
#define LEN 7001
|
|
|
|
static volatile int checksum;
|
|
|
|
int main(int argc, char **argv)
|
|
{
|
|
int i;
|
|
char data[LEN];
|
|
|
|
av_log_set_level(AV_LOG_DEBUG);
|
|
|
|
for (i = 0; i < LEN; i++)
|
|
data[i] = ((i * i) >> 3) + 123 * i;
|
|
|
|
if (argc > 1 && !strcmp(argv[1], "-t")) {
|
|
for (i = 0; i < 1000; i++) {
|
|
START_TIMER;
|
|
checksum = av_adler32_update(1, data, LEN);
|
|
STOP_TIMER("adler");
|
|
}
|
|
} else {
|
|
checksum = av_adler32_update(1, data, LEN);
|
|
}
|
|
|
|
av_log(NULL, AV_LOG_DEBUG, "%X (expected 50E6E508)\n", checksum);
|
|
return checksum == 0x50e6e508 ? 0 : 1;
|
|
}
|
|
#endif
|