diff options
author | Fabrice Bellard <fabrice@bellard.org> | 2002-11-25 19:07:40 +0000 |
---|---|---|
committer | Fabrice Bellard <fabrice@bellard.org> | 2002-11-25 19:07:40 +0000 |
commit | abac6175916c57f59ddb51ffe41bfd1d9851fe38 (patch) | |
tree | 8fc5b70a143f0f74468c353afbf043d7e104cdc0 /libavformat/crc.c | |
parent | 57fc25764261abe71b6cf7571eca182f8acf5795 (diff) | |
download | ffmpeg-streaming-abac6175916c57f59ddb51ffe41bfd1d9851fe38.zip ffmpeg-streaming-abac6175916c57f59ddb51ffe41bfd1d9851fe38.tar.gz |
renamed libav to libavformat
Originally committed as revision 1276 to svn://svn.ffmpeg.org/ffmpeg/trunk
Diffstat (limited to 'libavformat/crc.c')
-rw-r--r-- | libavformat/crc.c | 111 |
1 files changed, 111 insertions, 0 deletions
diff --git a/libavformat/crc.c b/libavformat/crc.c new file mode 100644 index 0000000..553ab53 --- /dev/null +++ b/libavformat/crc.c @@ -0,0 +1,111 @@ +/* + * CRC decoder (for codec/format testing) + * Copyright (c) 2002 Fabrice Bellard. + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ +#include "avformat.h" + +/* adler32.c -- compute the Adler-32 checksum of a data stream + * Copyright (C) 1995 Mark Adler + * For conditions of distribution and use, see copyright notice in zlib.h + */ + +#define BASE 65521L /* largest prime smaller than 65536 */ +#define NMAX 5552 +/* NMAX is the largest n such that 255n(n+1)/2 + (n+1)(BASE-1) <= 2^32-1 */ + +#define DO1(buf) {s1 += *buf++; s2 += s1;} +#define DO2(buf) DO1(buf); DO1(buf); +#define DO4(buf) DO2(buf); DO2(buf); +#define DO8(buf) DO4(buf); DO4(buf); +#define DO16(buf) DO8(buf); DO8(buf); + +static UINT32 adler32(UINT32 adler, UINT8 *buf, unsigned int len) +{ + unsigned long s1 = adler & 0xffff; + unsigned long s2 = (adler >> 16) & 0xffff; + int k; + + if (buf == NULL) return 1L; + + while (len > 0) { + k = len < NMAX ? len : NMAX; + len -= k; + while (k >= 16) { + DO16(buf); + k -= 16; + } + if (k != 0) do { + DO1(buf); + } while (--k); + s1 %= BASE; + s2 %= BASE; + } + return (s2 << 16) | s1; +} + +typedef struct CRCState { + UINT32 crcval; +} CRCState; + +static int crc_write_header(struct AVFormatContext *s) +{ + CRCState *crc = s->priv_data; + + /* init CRC */ + crc->crcval = adler32(0, NULL, 0); + + return 0; +} + +static int crc_write_packet(struct AVFormatContext *s, + int stream_index, + unsigned char *buf, int size, int force_pts) +{ + CRCState *crc = s->priv_data; + crc->crcval = adler32(crc->crcval, buf, size); + return 0; +} + +static int crc_write_trailer(struct AVFormatContext *s) +{ + CRCState *crc = s->priv_data; + char buf[64]; + + snprintf(buf, sizeof(buf), "CRC=%08x\n", crc->crcval); + put_buffer(&s->pb, buf, strlen(buf)); + put_flush_packet(&s->pb); + return 0; +} + +static AVOutputFormat crc_format = { + "crc", + "crc testing format", + NULL, + "", + sizeof(CRCState), + CODEC_ID_PCM_S16LE, + CODEC_ID_RAWVIDEO, + crc_write_header, + crc_write_packet, + crc_write_trailer, +}; + +int crc_init(void) +{ + av_register_output_format(&crc_format); + return 0; +} |