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 "bit.h"
29 # include "stream.h"
30
31 /*
32 * NAME: stream->init()
33 * DESCRIPTION: initialize stream struct
34 */
mad_stream_init(struct mad_stream * stream)35 void mad_stream_init(struct mad_stream *stream)
36 {
37 stream->buffer = 0;
38 stream->bufend = 0;
39 stream->skiplen = 0;
40
41 stream->sync = 0;
42 stream->freerate = 0;
43
44 stream->this_frame = 0;
45 stream->next_frame = 0;
46 mad_bit_init(&stream->ptr, 0);
47
48 mad_bit_init(&stream->anc_ptr, 0);
49 stream->anc_bitlen = 0;
50
51 stream->main_data = 0;
52 stream->md_len = 0;
53
54 stream->options = 0;
55 stream->error = MAD_ERROR_NONE;
56 }
57
58 /*
59 * NAME: stream->finish()
60 * DESCRIPTION: deallocate any dynamic memory associated with stream
61 */
mad_stream_finish(struct mad_stream * stream)62 void mad_stream_finish(struct mad_stream *stream)
63 {
64 if (stream->main_data) {
65 free(stream->main_data);
66 stream->main_data = 0;
67 }
68
69 mad_bit_finish(&stream->anc_ptr);
70 mad_bit_finish(&stream->ptr);
71 }
72
73 /*
74 * NAME: stream->buffer()
75 * DESCRIPTION: set stream buffer pointers
76 */
mad_stream_buffer(struct mad_stream * stream,unsigned char const * buffer,unsigned long length)77 void mad_stream_buffer(struct mad_stream *stream,
78 unsigned char const *buffer, unsigned long length)
79 {
80 stream->buffer = buffer;
81 stream->bufend = buffer + length;
82
83 stream->this_frame = buffer;
84 stream->next_frame = buffer;
85
86 stream->sync = 1;
87
88 mad_bit_init(&stream->ptr, buffer);
89 }
90
91 /*
92 * NAME: stream->skip()
93 * DESCRIPTION: arrange to skip bytes before the next frame
94 */
mad_stream_skip(struct mad_stream * stream,unsigned long length)95 void mad_stream_skip(struct mad_stream *stream, unsigned long length)
96 {
97 stream->skiplen += length;
98 }
99
100 /*
101 * NAME: stream->sync()
102 * DESCRIPTION: locate the next stream sync word
103 */
mad_stream_sync(struct mad_stream * stream)104 int mad_stream_sync(struct mad_stream *stream)
105 {
106 register unsigned char const *ptr, *end;
107
108 ptr = mad_bit_nextbyte(&stream->ptr);
109 end = stream->bufend;
110
111 while (ptr < end - 1 &&
112 !(ptr[0] == 0xff && (ptr[1] & 0xe0) == 0xe0))
113 ++ptr;
114
115 if (end - ptr < MAD_BUFFER_GUARD)
116 return -1;
117
118 mad_bit_init(&stream->ptr, ptr);
119
120 return 0;
121 }
122
123 /*
124 * NAME: stream->errorstr()
125 * DESCRIPTION: return a string description of the current error condition
126 */
mad_stream_errorstr(struct mad_stream const * stream)127 char const *mad_stream_errorstr(struct mad_stream const *stream)
128 {
129 switch (stream->error) {
130 case MAD_ERROR_NONE: return "no error";
131
132 case MAD_ERROR_BUFLEN: return "input buffer too small (or EOF)";
133 case MAD_ERROR_BUFPTR: return "invalid (null) buffer pointer";
134
135 case MAD_ERROR_NOMEM: return "not enough memory";
136
137 case MAD_ERROR_LOSTSYNC: return "lost synchronization";
138 case MAD_ERROR_BADLAYER: return "reserved header layer value";
139 case MAD_ERROR_BADBITRATE: return "forbidden bitrate value";
140 case MAD_ERROR_BADSAMPLERATE: return "reserved sample frequency value";
141 case MAD_ERROR_BADEMPHASIS: return "reserved emphasis value";
142
143 case MAD_ERROR_BADCRC: return "CRC check failed";
144 case MAD_ERROR_BADBITALLOC: return "forbidden bit allocation value";
145 case MAD_ERROR_BADSCALEFACTOR: return "bad scalefactor index";
146 case MAD_ERROR_BADMODE: return "bad bitrate/mode combination";
147 case MAD_ERROR_BADFRAMELEN: return "bad frame length";
148 case MAD_ERROR_BADBIGVALUES: return "bad big_values count";
149 case MAD_ERROR_BADBLOCKTYPE: return "reserved block_type";
150 case MAD_ERROR_BADSCFSI: return "bad scalefactor selection info";
151 case MAD_ERROR_BADDATAPTR: return "bad main_data_begin pointer";
152 case MAD_ERROR_BADPART3LEN: return "bad audio data length";
153 case MAD_ERROR_BADHUFFTABLE: return "bad Huffman table select";
154 case MAD_ERROR_BADHUFFDATA: return "Huffman data overrun";
155 case MAD_ERROR_BADSTEREO: return "incompatible block_type for JS";
156 }
157
158 return 0;
159 }
160