1/*
2 * Copyright (c) 2011  Justin Ruggles
3 *
4 * This file is part of Libav.
5 *
6 * Libav is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * Libav is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with Libav; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21/**
22 * @file
23 * ADX audio parser
24 *
25 * Splits packets into individual blocks.
26 */
27
28#include "libavutil/intreadwrite.h"
29#include "parser.h"
30#include "adx.h"
31
32typedef struct ADXParseContext {
33    ParseContext pc;
34    int header_size;
35    int block_size;
36    int remaining;
37} ADXParseContext;
38
39static int adx_parse(AVCodecParserContext *s1,
40                           AVCodecContext *avctx,
41                           const uint8_t **poutbuf, int *poutbuf_size,
42                           const uint8_t *buf, int buf_size)
43{
44    ADXParseContext *s = s1->priv_data;
45    ParseContext *pc = &s->pc;
46    int next = END_NOT_FOUND;
47    int i;
48    uint64_t state = pc->state64;
49
50    if (!s->header_size) {
51        for (i = 0; i < buf_size; i++) {
52            state = (state << 8) | buf[i];
53            /* check for fixed fields in ADX header for possible match */
54            if ((state & 0xFFFF0000FFFFFF00) == 0x8000000003120400ULL) {
55                int channels    = state & 0xFF;
56                int header_size = ((state >> 32) & 0xFFFF) + 4;
57                if (channels > 0 && header_size >= 8) {
58                    s->header_size = header_size;
59                    s->block_size  = BLOCK_SIZE * channels;
60                    s->remaining   = i - 7 + s->header_size + s->block_size;
61                    break;
62                }
63            }
64        }
65        pc->state64 = state;
66    }
67
68    if (s->header_size) {
69        if (!s->remaining)
70            s->remaining = s->block_size;
71        if (s->remaining <= buf_size) {
72            next = s->remaining;
73            s->remaining = 0;
74        } else
75            s->remaining -= buf_size;
76    }
77
78    if (ff_combine_frame(pc, next, &buf, &buf_size) < 0 || !buf_size) {
79        *poutbuf      = NULL;
80        *poutbuf_size = 0;
81        return buf_size;
82    }
83    *poutbuf = buf;
84    *poutbuf_size = buf_size;
85    return next;
86}
87
88AVCodecParser ff_adx_parser = {
89    .codec_ids      = { CODEC_ID_ADPCM_ADX },
90    .priv_data_size = sizeof(ADXParseContext),
91    .parser_parse   = adx_parse,
92    .parser_close   = ff_parse_close,
93};
94