path: root/audio_codec/libmad/stream.c (plain)
blob: fea06dac9bd623fbf93f8dab5d59051dbce5daf8

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	*/
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	*/
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	*/
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	*/
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	*/
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
118	if (end - ptr < MAD_BUFFER_GUARD) {
119	return -1;
120	}
121
122	mad_bit_init(&stream->ptr, ptr);
123
124	return 0;
125	}
126
127	/*
128	* NAME: stream->errorstr()
129	* DESCRIPTION: return a string description of the current error condition
130	*/
131	char const *mad_stream_errorstr(struct mad_stream const *stream)
132	{
133	switch (stream->error) {
134	case MAD_ERROR_NONE:
135	return "no error";
136
137	case MAD_ERROR_BUFLEN:
138	return "input buffer too small (or EOF)";
139	case MAD_ERROR_BUFPTR:
140	return "invalid (null) buffer pointer";
141
142	case MAD_ERROR_NOMEM:
143	return "not enough memory";
144
145	case MAD_ERROR_LOSTSYNC:
146	return "lost synchronization";
147	case MAD_ERROR_BADLAYER:
148	return "reserved header layer value";
149	case MAD_ERROR_BADBITRATE:
150	return "forbidden bitrate value";
151	case MAD_ERROR_BADSAMPLERATE:
152	return "reserved sample frequency value";
153	case MAD_ERROR_BADEMPHASIS:
154	return "reserved emphasis value";
155
156	case MAD_ERROR_BADCRC:
157	return "CRC check failed";
158	case MAD_ERROR_BADBITALLOC:
159	return "forbidden bit allocation value";
160	case MAD_ERROR_BADSCALEFACTOR:
161	return "bad scalefactor index";
162	case MAD_ERROR_BADMODE:
163	return "bad bitrate/mode combination";
164	case MAD_ERROR_BADFRAMELEN:
165	return "bad frame length";
166	case MAD_ERROR_BADBIGVALUES:
167	return "bad big_values count";
168	case MAD_ERROR_BADBLOCKTYPE:
169	return "reserved block_type";
170	case MAD_ERROR_BADSCFSI:
171	return "bad scalefactor selection info";
172	case MAD_ERROR_BADDATAPTR:
173	return "bad main_data_begin pointer";
174	case MAD_ERROR_BADPART3LEN:
175	return "bad audio data length";
176	case MAD_ERROR_BADHUFFTABLE:
177	return "bad Huffman table select";
178	case MAD_ERROR_BADHUFFDATA:
179	return "Huffman data overrun";
180	case MAD_ERROR_BADSTEREO:
181	return "incompatible block_type for JS";
182	}
183
184	return 0;
185	}
186