adler32: make test program more useful and add fate test
[libav.git] / libavutil / adler32.c
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 #include "config.h"
25 #include "adler32.h"
26
27 #define BASE 65521L /* largest prime smaller than 65536 */
28
29 #define DO1(buf) {s1 += *buf++; s2 += s1;}
30 #define DO4(buf) DO1(buf); DO1(buf); DO1(buf); DO1(buf);
31 #define DO16(buf) DO4(buf); DO4(buf); DO4(buf); DO4(buf);
32
33 unsigned long av_adler32_update(unsigned long adler, const uint8_t *buf, unsigned int len)
34 {
35 unsigned long s1 = adler & 0xffff;
36 unsigned long s2 = adler >> 16;
37
38 while (len>0) {
39 #if CONFIG_SMALL
40 while(len>4 && s2 < (1U<<31)){
41 DO4(buf); len-=4;
42 #else
43 while(len>16 && s2 < (1U<<31)){
44 DO16(buf); len-=16;
45 #endif
46 }
47 DO1(buf); len--;
48 s1 %= BASE;
49 s2 %= BASE;
50 }
51 return (s2 << 16) | s1;
52 }
53
54 #ifdef TEST
55 #include <string.h>
56 #include "log.h"
57 #include "timer.h"
58 #define LEN 7001
59 volatile int checksum;
60 int main(int argc, char **argv)
61 {
62 int i;
63 char data[LEN];
64 av_log_set_level(AV_LOG_DEBUG);
65 for(i=0; i<LEN; i++)
66 data[i]= ((i*i)>>3) + 123*i;
67
68 if (argc > 1 && !strcmp(argv[1], "-t")) {
69 for (i = 0; i < 1000; i++) {
70 START_TIMER;
71 checksum = av_adler32_update(1, data, LEN);
72 STOP_TIMER("adler");
73 }
74 } else {
75 checksum = av_adler32_update(1, data, LEN);
76 }
77
78 av_log(NULL, AV_LOG_DEBUG, "%X (expected 50E6E508)\n", checksum);
79 return checksum == 0x50e6e508? 0 : 1;
80 }
81 #endif