d28a87cdf5c506269167191199a4d93febe37720
[libav.git] / libavformat / crc.c
1 /*
2 * CRC decoder (for codec/format testing)
3 * Copyright (c) 2002 Fabrice Bellard.
4 *
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation; either
8 * version 2 of the License, or (at your option) any later version.
9 *
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Lesser General Public License for more details.
14 *
15 * You should have received a copy of the GNU Lesser General Public
16 * License along with this library; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
18 */
19 #include "avformat.h"
20
21 /* adler32.c -- compute the Adler-32 checksum of a data stream
22 * Copyright (C) 1995 Mark Adler
23 * For conditions of distribution and use, see copyright notice in zlib.h
24 */
25
26 #define BASE 65521L /* largest prime smaller than 65536 */
27 #define NMAX 5552
28 /* NMAX is the largest n such that 255n(n+1)/2 + (n+1)(BASE-1) <= 2^32-1 */
29
30 #define DO1(buf) {s1 += *buf++; s2 += s1;}
31 #define DO2(buf) DO1(buf); DO1(buf);
32 #define DO4(buf) DO2(buf); DO2(buf);
33 #define DO8(buf) DO4(buf); DO4(buf);
34 #define DO16(buf) DO8(buf); DO8(buf);
35
36 unsigned long update_adler32(unsigned long adler, const uint8_t *buf, unsigned int len)
37 {
38 unsigned long s1 = adler & 0xffff;
39 unsigned long s2 = (adler >> 16) & 0xffff;
40 int k;
41
42 if (buf == NULL) return 1L;
43
44 while (len > 0) {
45 k = len < NMAX ? len : NMAX;
46 len -= k;
47 while (k >= 16) {
48 DO16(buf);
49 k -= 16;
50 }
51 if (k != 0) do {
52 DO1(buf);
53 } while (--k);
54 s1 %= BASE;
55 s2 %= BASE;
56 }
57 return (s2 << 16) | s1;
58 }
59
60 typedef struct CRCState {
61 uint32_t crcval;
62 } CRCState;
63
64 static int crc_write_header(struct AVFormatContext *s)
65 {
66 CRCState *crc = s->priv_data;
67
68 /* init CRC */
69 crc->crcval = update_adler32(0, NULL, 0);
70
71 return 0;
72 }
73
74 static int crc_write_packet(struct AVFormatContext *s, AVPacket *pkt)
75 {
76 CRCState *crc = s->priv_data;
77 crc->crcval = update_adler32(crc->crcval, pkt->data, pkt->size);
78 return 0;
79 }
80
81 static int crc_write_trailer(struct AVFormatContext *s)
82 {
83 CRCState *crc = s->priv_data;
84 char buf[64];
85
86 snprintf(buf, sizeof(buf), "CRC=0x%08x\n", crc->crcval);
87 put_buffer(&s->pb, buf, strlen(buf));
88 put_flush_packet(&s->pb);
89 return 0;
90 }
91
92 static int framecrc_write_packet(struct AVFormatContext *s, AVPacket *pkt)
93 {
94 uint32_t crc = update_adler32(0, pkt->data, pkt->size);
95 char buf[256];
96
97 snprintf(buf, sizeof(buf), "%d, %"PRId64", %d, 0x%08x\n", pkt->stream_index, pkt->dts, pkt->size, crc);
98 put_buffer(&s->pb, buf, strlen(buf));
99 put_flush_packet(&s->pb);
100 return 0;
101 }
102
103 static AVOutputFormat crc_format = {
104 "crc",
105 "crc testing format",
106 NULL,
107 "",
108 sizeof(CRCState),
109 CODEC_ID_PCM_S16LE,
110 CODEC_ID_RAWVIDEO,
111 crc_write_header,
112 crc_write_packet,
113 crc_write_trailer,
114 };
115
116 static AVOutputFormat framecrc_format = {
117 "framecrc",
118 "framecrc testing format",
119 NULL,
120 "",
121 0,
122 CODEC_ID_PCM_S16LE,
123 CODEC_ID_RAWVIDEO,
124 NULL,
125 framecrc_write_packet,
126 NULL,
127 };
128
129 int crc_init(void)
130 {
131 av_register_output_format(&crc_format);
132 av_register_output_format(&framecrc_format);
133 return 0;
134 }