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 # include "global.h"
23
24 # include <stdlib.h>
25
26 # include "bit.h"
27 # include "stream.h"
28
29 /*
30 * NAME: stream->init()
31 * DESCRIPTION: initialize stream struct
32 */
mad_stream_init(struct mad_stream * stream)33 void mad_stream_init(struct mad_stream *stream)
34 {
35 stream->buffer = 0;
36 stream->bufend = 0;
37 stream->skiplen = 0;
38
39 stream->sync = 0;
40 stream->freerate = 0;
41
42 stream->this_frame = 0;
43 stream->next_frame = 0;
44 mad_bit_init(&stream->ptr, 0);
45
46 mad_bit_init(&stream->anc_ptr, 0);
47 stream->anc_bitlen = 0;
48
49 stream->main_data = 0;
50 stream->md_len = 0;
51
52 stream->options = 0;
53 stream->error = MAD_ERROR_NONE;
54 }
55
56 /*
57 * NAME: stream->finish()
58 * DESCRIPTION: deallocate any dynamic memory associated with stream
59 */
mad_stream_finish(struct mad_stream * stream)60 void mad_stream_finish(struct mad_stream *stream)
61 {
62 if (stream->main_data) {
63 free(stream->main_data);
64 stream->main_data = 0;
65 }
66
67 mad_bit_finish(&stream->anc_ptr);
68 mad_bit_finish(&stream->ptr);
69 }
70
71 /*
72 * NAME: stream->buffer()
73 * DESCRIPTION: set stream buffer pointers
74 */
mad_stream_buffer(struct mad_stream * stream,unsigned char const * buffer,unsigned long length)75 void mad_stream_buffer(struct mad_stream *stream,
76 unsigned char const *buffer, unsigned long length)
77 {
78 stream->buffer = buffer;
79 stream->bufend = buffer + length;
80
81 stream->this_frame = buffer;
82 stream->next_frame = buffer;
83
84 stream->sync = 1;
85
86 mad_bit_init(&stream->ptr, buffer);
87 }
88
89 /*
90 * NAME: stream->skip()
91 * DESCRIPTION: arrange to skip bytes before the next frame
92 */
mad_stream_skip(struct mad_stream * stream,unsigned long length)93 void mad_stream_skip(struct mad_stream *stream, unsigned long length)
94 {
95 stream->skiplen += length;
96 }
97
98 /*
99 * NAME: stream->sync()
100 * DESCRIPTION: locate the next stream sync word
101 */
mad_stream_sync(struct mad_stream * stream)102 int mad_stream_sync(struct mad_stream *stream)
103 {
104 register unsigned char const *ptr, *end;
105
106 ptr = mad_bit_nextbyte(&stream->ptr);
107 end = stream->bufend;
108
109 while (ptr < end - 1 &&
110 !(ptr[0] == 0xff && (ptr[1] & 0xe0) == 0xe0))
111 ++ptr;
112
113 if (end - ptr < MAD_BUFFER_GUARD)
114 return -1;
115
116 mad_bit_init(&stream->ptr, ptr);
117
118 return 0;
119 }
120
121 /*
122 * NAME: stream->errorstr()
123 * DESCRIPTION: return a string description of the current error condition
124 */
mad_stream_errorstr(struct mad_stream const * stream)125 char const *mad_stream_errorstr(struct mad_stream const *stream)
126 {
127 switch (stream->error) {
128 case MAD_ERROR_NONE: return "no error";
129
130 case MAD_ERROR_BUFLEN: return "input buffer too small (or EOF)";
131 case MAD_ERROR_BUFPTR: return "invalid (null) buffer pointer";
132
133 case MAD_ERROR_NOMEM: return "not enough memory";
134
135 case MAD_ERROR_LOSTSYNC: return "lost synchronization";
136 case MAD_ERROR_BADLAYER: return "reserved header layer value";
137 case MAD_ERROR_BADBITRATE: return "forbidden bitrate value";
138 case MAD_ERROR_BADSAMPLERATE: return "reserved sample frequency value";
139 case MAD_ERROR_BADEMPHASIS: return "reserved emphasis value";
140
141 case MAD_ERROR_BADCRC: return "CRC check failed";
142 case MAD_ERROR_BADBITALLOC: return "forbidden bit allocation value";
143 case MAD_ERROR_BADSCALEFACTOR: return "bad scalefactor index";
144 case MAD_ERROR_BADMODE: return "bad bitrate/mode combination";
145 case MAD_ERROR_BADFRAMELEN: return "bad frame length";
146 case MAD_ERROR_BADBIGVALUES: return "bad big_values count";
147 case MAD_ERROR_BADBLOCKTYPE: return "reserved block_type";
148 case MAD_ERROR_BADSCFSI: return "bad scalefactor selection info";
149 case MAD_ERROR_BADDATAPTR: return "bad main_data_begin pointer";
150 case MAD_ERROR_BADPART3LEN: return "bad audio data length";
151 case MAD_ERROR_BADHUFFTABLE: return "bad Huffman table select";
152 case MAD_ERROR_BADHUFFDATA: return "Huffman data overrun";
153 case MAD_ERROR_BADSTEREO: return "incompatible block_type for JS";
154 }
155
156 return 0;
157 }
158