[deb_ffmpeg.git] / ffmpeg / libavutil / adler32.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"
#include "common.h"
#include "intreadwrite.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 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;
}

#ifdef TEST
// LCOV_EXCL_START
#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;
}
// LCOV_EXCL_STOP
#endif
Commit	Line	Data
2ba45a60 DM	1	/*
	2	* Compute the Adler-32 checksum of a data stream.
	3	* This is a modified version based on adler32.c from the zlib library.
	4	*
	5	* Copyright (C) 1995 Mark Adler
	6	*
	7	* This software is provided 'as-is', without any express or implied
	8	* warranty. In no event will the authors be held liable for any damages
	9	* arising from the use of this software.
	10	*
	11	* Permission is granted to anyone to use this software for any purpose,
	12	* including commercial applications, and to alter it and redistribute it
	13	* freely, subject to the following restrictions:
	14	*
	15	* 1. The origin of this software must not be misrepresented; you must not
	16	* claim that you wrote the original software. If you use this software
	17	* in a product, an acknowledgment in the product documentation would be
	18	* appreciated but is not required.
	19	* 2. Altered source versions must be plainly marked as such, and must not be
	20	* misrepresented as being the original software.
	21	* 3. This notice may not be removed or altered from any source distribution.
	22	*/
	23
	24	/**
	25	* @file
	26	* Computes the Adler-32 checksum of a data stream
	27	*
	28	* This is a modified version based on adler32.c from the zlib library.
	29	* @author Mark Adler
	30	* @ingroup lavu_adler32
	31	*/
	32
	33	#include "config.h"
	34	#include "adler32.h"
	35	#include "common.h"
	36	#include "intreadwrite.h"
	37
	38	#define BASE 65521L /* largest prime smaller than 65536 */
	39
	40	#define DO1(buf) { s1 += *buf++; s2 += s1; }
	41	#define DO4(buf) DO1(buf); DO1(buf); DO1(buf); DO1(buf);
	42	#define DO16(buf) DO4(buf); DO4(buf); DO4(buf); DO4(buf);
	43
	44	unsigned long av_adler32_update(unsigned long adler, const uint8_t * buf,
	45	unsigned int len)
	46	{
	47	unsigned long s1 = adler & 0xffff;
	48	unsigned long s2 = adler >> 16;
	49
	50	while (len > 0) {
	51	#if HAVE_FAST_64BIT && HAVE_FAST_UNALIGNED && !CONFIG_SMALL
	52	unsigned len2 = FFMIN((len-1) & ~7, 23*8);
	53	if (len2) {
	54	uint64_t a1= 0;
	55	uint64_t a2= 0;
	56	uint64_t b1= 0;
	57	uint64_t b2= 0;
	58	len -= len2;
	59	s2 += s1*len2;
	60	while (len2 >= 8) {
	61	uint64_t v = AV_RN64(buf);
	62	a2 += a1;
	63	b2 += b1;
	64	a1 += v &0x00FF00FF00FF00FF;
65	b1 += (v>>8)&0x00FF00FF00FF00FF;
66	len2 -= 8;
67	buf+=8;
68	}
69
70	//We combine the 8 interleaved adler32 checksums without overflows
71	//Decreasing the number of iterations would allow below code to be
72	//simplified but would likely be slower due to the fewer iterations
73	//of the inner loop
74	s1 += ((a1+b1)*0x1000100010001)>>48;
75	s2 += ((((a2&0xFFFF0000FFFF)+(b2&0xFFFF0000FFFF)+((a2>>16)&0xFFFF0000FFFF)+((b2>>16)&0xFFFF0000FFFF))*0x800000008)>>32)
76	#if HAVE_BIGENDIAN
77	+ 2((b10x1000200030004)>>48)
78	+ ((a1*0x1000100010001)>>48)
79	+ 2((a10x0000100020003)>>48);
80	#else
81	+ 2((a10x4000300020001)>>48)
82	+ ((b1*0x1000100010001)>>48)
83	+ 2((b10x3000200010000)>>48);
84	#endif
85	}
86	#else
87	while (len > 4 && s2 < (1U << 31)) {
88	DO4(buf);
89	len -= 4;
90	}
91	#endif
92	DO1(buf); len--;
93	s1 %= BASE;
94	s2 %= BASE;
95	}
96	return (s2 << 16) \| s1;
97	}
98
99	#ifdef TEST
100	// LCOV_EXCL_START
101	#include <string.h>
102	#include "log.h"
103	#include "timer.h"
104	#define LEN 7001
105
106	static volatile int checksum;
107
108	int main(int argc, char **argv)
109	{
110	int i;
111	char data[LEN];
112
113	av_log_set_level(AV_LOG_DEBUG);
114
115	for (i = 0; i < LEN; i++)
116	data[i] = ((i * i) >> 3) + 123 * i;
117
118	if (argc > 1 && !strcmp(argv[1], "-t")) {
119	for (i = 0; i < 1000; i++) {
120	START_TIMER;
121	checksum = av_adler32_update(1, data, LEN);
122	STOP_TIMER("adler");
123	}
124	} else {
125	checksum = av_adler32_update(1, data, LEN);
126	}
127
128	av_log(NULL, AV_LOG_DEBUG, "%X (expected 50E6E508)\n", checksum);
129	return checksum == 0x50e6e508 ? 0 : 1;
130	}
131	// LCOV_EXCL_STOP
132	#endif