1 /*
2 * libmad - MPEG audio decoder library
3 * Copyright (C) 2000-2004 Underbit Technologies, Inc.
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program 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
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 *
19 * $Id: stream.c,v 1.12 2004/02/05 09:02:39 rob Exp $
20 */
21
22 # ifdef HAVE_CONFIG_H
23 # include "config.h"
24 # endif
25
26 # include "global.h"
27
28 # include <stdlib.h>
29
30 # include "bit.h"
31 # include "stream.h"
32
33 /*
34 * NAME: stream->init()
35 * DESCRIPTION: initialize stream struct
36 */
mad_stream_init(struct mad_stream * stream)37 void mad_stream_init(struct mad_stream *stream)
38 {
39 stream->buffer = 0;
40 stream->bufend = 0;
41 stream->skiplen = 0;
42
43 stream->sync = 0;
44 stream->freerate = 0;
45
46 stream->this_frame = 0;
47 stream->next_frame = 0;
48 mad_bit_init(&stream->ptr, 0);
49
50 mad_bit_init(&stream->anc_ptr, 0);
51 stream->anc_bitlen = 0;
52
53 stream->main_data = 0;
54 stream->md_len = 0;
55
56 stream->options = 0;
57 stream->error = MAD_ERROR_NONE;
58 }
59
60 /*
61 * NAME: stream->finish()
62 * DESCRIPTION: deallocate any dynamic memory associated with stream
63 */
mad_stream_finish(struct mad_stream * stream)64 void mad_stream_finish(struct mad_stream *stream)
65 {
66 if (stream->main_data) {
67 free(stream->main_data);
68 stream->main_data = 0;
69 }
70
71 mad_bit_finish(&stream->anc_ptr);
72 mad_bit_finish(&stream->ptr);
73 }
74
75 /*
76 * NAME: stream->buffer()
77 * DESCRIPTION: set stream buffer pointers
78 */
mad_stream_buffer(struct mad_stream * stream,unsigned char const * buffer,unsigned long length)79 void mad_stream_buffer(struct mad_stream *stream,
80 unsigned char const *buffer, unsigned long length)
81 {
82 stream->buffer = buffer;
83 stream->bufend = buffer + length;
84
85 stream->this_frame = buffer;
86 stream->next_frame = buffer;
87
88 stream->sync = 1;
89
90 mad_bit_init(&stream->ptr, buffer);
91 }
92
93 /*
94 * NAME: stream->skip()
95 * DESCRIPTION: arrange to skip bytes before the next frame
96 */
mad_stream_skip(struct mad_stream * stream,unsigned long length)97 void mad_stream_skip(struct mad_stream *stream, unsigned long length)
98 {
99 stream->skiplen += length;
100 }
101
102 /*
103 * NAME: stream->sync()
104 * DESCRIPTION: locate the next stream sync word
105 */
mad_stream_sync(struct mad_stream * stream)106 int mad_stream_sync(struct mad_stream *stream)
107 {
108 register unsigned char const *ptr, *end;
109
110 ptr = mad_bit_nextbyte(&stream->ptr);
111 end = stream->bufend;
112
113 while (ptr < end - 1 &&
114 !(ptr[0] == 0xff && (ptr[1] & 0xe0) == 0xe0))
115 ++ptr;
116
117 if (end - ptr < MAD_BUFFER_GUARD)
118 return -1;
119
120 mad_bit_init(&stream->ptr, ptr);
121
122 return 0;
123 }
124
125 /*
126 * NAME: stream->errorstr()
127 * DESCRIPTION: return a string description of the current error condition
128 */
mad_stream_errorstr(struct mad_stream const * stream)129 char const *mad_stream_errorstr(struct mad_stream const *stream)
130 {
131 switch (stream->error) {
132 case MAD_ERROR_NONE: return "no error";
133
134 case MAD_ERROR_BUFLEN: return "input buffer too small (or EOF)";
135 case MAD_ERROR_BUFPTR: return "invalid (null) buffer pointer";
136
137 case MAD_ERROR_NOMEM: return "not enough memory";
138
139 case MAD_ERROR_LOSTSYNC: return "lost synchronization";
140 case MAD_ERROR_BADLAYER: return "reserved header layer value";
141 case MAD_ERROR_BADBITRATE: return "forbidden bitrate value";
142 case MAD_ERROR_BADSAMPLERATE: return "reserved sample frequency value";
143 case MAD_ERROR_BADEMPHASIS: return "reserved emphasis value";
144
145 case MAD_ERROR_BADCRC: return "CRC check failed";
146 case MAD_ERROR_BADBITALLOC: return "forbidden bit allocation value";
147 case MAD_ERROR_BADSCALEFACTOR: return "bad scalefactor index";
148 case MAD_ERROR_BADMODE: return "bad bitrate/mode combination";
149 case MAD_ERROR_BADFRAMELEN: return "bad frame length";
150 case MAD_ERROR_BADBIGVALUES: return "bad big_values count";
151 case MAD_ERROR_BADBLOCKTYPE: return "reserved block_type";
152 case MAD_ERROR_BADSCFSI: return "bad scalefactor selection info";
153 case MAD_ERROR_BADDATAPTR: return "bad main_data_begin pointer";
154 case MAD_ERROR_BADPART3LEN: return "bad audio data length";
155 case MAD_ERROR_BADHUFFTABLE: return "bad Huffman table select";
156 case MAD_ERROR_BADHUFFDATA: return "Huffman data overrun";
157 case MAD_ERROR_BADSTEREO: return "incompatible block_type for JS";
158 }
159
160 return 0;
161 }
162