d12b5b2f13
This avoids spurious library rebuilds when only the test program code is changed and simplifies the build system.
66 lines
2.0 KiB
C
66 lines
2.0 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;
|
|
}
|