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comparison decoders/wav.c @ 17:102cf61c0816

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Initial add.
author Ryan C. Gordon <icculus@icculus.org>
date Wed, 19 Sep 2001 08:22:33 +0000
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children c15396fc0e55
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16:3efbcaf36fec 17:102cf61c0816
1 /*
2 * SDL_sound -- An abstract sound format decoding API.
3 * Copyright (C) 2001 Ryan C. Gordon.
4 *
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation; either
8 * version 2.1 of the License, or (at your option) any later version.
9 *
10 * This library 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 GNU
13 * Lesser General Public License for more details.
14 *
15 * You should have received a copy of the GNU Lesser General Public
16 * License along with this library; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 */
19
20 /*
21 * WAV decoder for SDL_sound.
22 *
23 * This driver handles Microsoft .WAVs, in as many of the thousands of
24 * variations as we can.
25 *
26 * Please see the file LICENSE in the source's root directory.
27 *
28 * This file written by Ryan C. Gordon. (icculus@clutteredmind.org)
29 */
30
31 #include <stdio.h>
32 #include <stdlib.h>
33 #include <string.h>
34 #include <assert.h>
35 #include "SDL_sound.h"
36
37 #define __SDL_SOUND_INTERNAL__
38 #include "SDL_sound_internal.h"
39
40 #if (!defined SOUND_SUPPORTS_WAV)
41 #error SOUND_SUPPORTS_WAV must be defined.
42 #endif
43
44 static int WAV_open(Sound_Sample *sample, const char *ext);
45 static void WAV_close(Sound_Sample *sample);
46 static Uint32 WAV_read(Sound_Sample *sample);
47
48 const Sound_DecoderFunctions __Sound_DecoderFunctions_WAV =
49 {
50 {
51 "WAV",
52 "Microsoft WAVE audio format",
53 "Ryan C. Gordon <icculus@clutteredmind.org>",
54 "http://www.icculus.org/SDL_sound/"
55 },
56
57 WAV_open, /* open() method */
58 WAV_close, /* close() method */
59 WAV_read /* read() method */
60 };
61
62
63 /* this is what we store in our internal->decoder_private field... */
64 typedef struct
65 {
66 Sint32 bytesLeft;
67 } wav_t;
68
69
70 /* Chunk management code... */
71
72 #define riffID 0x46464952 /* "RIFF", in ascii. */
73 #define waveID 0x45564157 /* "WAVE", in ascii. */
74
75
76 #define fmtID 0x20746D66 /* "fmt ", in ascii. */
77
78 #define FMT_NORMAL 1 /* Uncompressed waveform data. */
79
80 typedef struct
81 {
82 Uint32 chunkID;
83 Sint32 chunkSize;
84 Sint16 wFormatTag;
85 Uint16 wChannels;
86 Uint32 dwSamplesPerSec;
87 Uint32 dwAvgBytesPerSec;
88 Uint16 wBlockAlign;
89 Uint16 wBitsPerSample;
90 } fmt_t;
91
92
93 /*
94 * Read in a fmt_t from disk. This makes this process safe regardless of
95 * the processor's byte order or how the fmt_t structure is packed.
96 */
97 static int read_fmt_chunk(SDL_RWops *rw, fmt_t *fmt)
98 {
99 /* skip reading the chunk ID, since it was already read at this point... */
100 fmt->chunkID = fmtID;
101
102 if (SDL_RWread(rw, &fmt->chunkSize, sizeof (fmt->chunkSize), 1) != 1)
103 return(0);
104 fmt->chunkSize = SDL_SwapLE32(fmt->chunkSize);
105
106 if (SDL_RWread(rw, &fmt->wFormatTag, sizeof (fmt->wFormatTag), 1) != 1)
107 return(0);
108 fmt->wFormatTag = SDL_SwapLE16(fmt->wFormatTag);
109
110 if (SDL_RWread(rw, &fmt->wChannels, sizeof (fmt->wChannels), 1) != 1)
111 return(0);
112 fmt->wChannels = SDL_SwapLE16(fmt->wChannels);
113
114 if (SDL_RWread(rw, &fmt->dwSamplesPerSec,
115 sizeof (fmt->dwSamplesPerSec), 1) != 1)
116 return(0);
117 fmt->dwSamplesPerSec = SDL_SwapLE32(fmt->dwSamplesPerSec);
118
119 if (SDL_RWread(rw, &fmt->dwAvgBytesPerSec,
120 sizeof (fmt->dwAvgBytesPerSec), 1) != 1)
121 return(0);
122 fmt->dwAvgBytesPerSec = SDL_SwapLE32(fmt->dwAvgBytesPerSec);
123
124 if (SDL_RWread(rw, &fmt->wBlockAlign, sizeof (fmt->wBlockAlign), 1) != 1)
125 return(0);
126 fmt->wBlockAlign = SDL_SwapLE16(fmt->wBlockAlign);
127
128 if (SDL_RWread(rw, &fmt->wBitsPerSample,
129 sizeof (fmt->wBitsPerSample), 1) != 1)
130 return(0);
131 fmt->wBitsPerSample = SDL_SwapLE16(fmt->wBitsPerSample);
132
133 return(1);
134 } /* read_fmt_chunk */
135
136
137 #define dataID 0x61746164 /* "data", in ascii. */
138
139 typedef struct
140 {
141 Uint32 chunkID;
142 Sint32 chunkSize;
143 /* Then, (chunkSize) bytes of waveform data... */
144 } data_t;
145
146
147 /*
148 * Read in a fmt_t from disk. This makes this process safe regardless of
149 * the processor's byte order or how the fmt_t structure is packed.
150 */
151 static int read_data_chunk(SDL_RWops *rw, data_t *data)
152 {
153 /* skip reading the chunk ID, since it was already read at this point... */
154 data->chunkID = dataID;
155
156 if (SDL_RWread(rw, &data->chunkSize, sizeof (data->chunkSize), 1) != 1)
157 return(0);
158 data->chunkSize = SDL_SwapLE32(data->chunkSize);
159
160 return(1);
161 } /* read_fmt_chunk */
162
163
164 static int find_chunk(SDL_RWops *rw, Uint32 id)
165 {
166 Sint32 siz = 0;
167 Uint32 _id = 0;
168
169 while (1)
170 {
171 BAIL_IF_MACRO(SDL_RWread(rw, &_id, sizeof (_id), 1) != 1, NULL, 0);
172 if (SDL_SwapLE32(_id) == id)
173 return(1);
174
175 BAIL_IF_MACRO(SDL_RWread(rw, &siz, sizeof (siz), 1) != 1, NULL, 0);
176 siz = SDL_SwapLE32(siz);
177 assert(siz > 0);
178 BAIL_IF_MACRO(SDL_RWseek(rw, siz, SEEK_SET) != siz, NULL, 0);
179 } /* while */
180
181 return(0); /* shouldn't hit this, but just in case... */
182 } /* find_chunk */
183
184
185 static int WAV_open(Sound_Sample *sample, const char *ext)
186 {
187 Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;
188 SDL_RWops *rw = internal->rw;
189 fmt_t f;
190 data_t d;
191 wav_t *w;
192
193 BAIL_IF_MACRO(SDL_ReadLE32(rw) != riffID, "WAV: Not a RIFF file.", 0);
194 SDL_ReadLE32(rw); /* throw the length away; we get this info later. */
195 BAIL_IF_MACRO(SDL_ReadLE32(rw) != waveID, "WAV: Not a WAVE file.", 0);
196 BAIL_IF_MACRO(!find_chunk(rw, fmtID), "WAV: No format chunk.", 0);
197 BAIL_IF_MACRO(!read_fmt_chunk(rw, &f), "WAV: Can't read format chunk.", 0);
198
199 /* !!! FIXME: This will have to change for compression types... */
200 BAIL_IF_MACRO(f.wFormatTag != FMT_NORMAL, "WAV: Unsupported encoding.", 0);
201
202 sample->actual.channels = (Uint8) f.wChannels;
203 sample->actual.rate = f.dwSamplesPerSec;
204
205 if (f.wBitsPerSample <= 8)
206 sample->actual.format = AUDIO_U8;
207 else if (f.wBitsPerSample <= 16)
208 sample->actual.format = AUDIO_S16LSB;
209 else
210 BAIL_MACRO("WAV: Unsupported sample size.", 0);
211
212 BAIL_IF_MACRO(!find_chunk(rw, dataID), "WAV: No data chunk.", 0);
213 BAIL_IF_MACRO(!read_data_chunk(rw, &d), "WAV: Can't read data chunk.", 0);
214
215 w = (wav_t *) malloc(sizeof(wav_t));
216 BAIL_IF_MACRO(w == NULL, ERR_OUT_OF_MEMORY, 0);
217 w->bytesLeft = d.chunkSize;
218 internal->decoder_private = (void *) w;
219
220 sample->flags = SOUND_SAMPLEFLAG_NONE;
221
222 _D(("WAV: Accepting data stream.\n"));
223 return(1); /* we'll handle this data. */
224 } /* WAV_open */
225
226
227 static void WAV_close(Sound_Sample *sample)
228 {
229 Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;
230 free(internal->decoder_private);
231 } /* WAV_close */
232
233
234 static Uint32 WAV_read(Sound_Sample *sample)
235 {
236 Uint32 retval;
237 Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;
238 wav_t *w = (wav_t *) internal->decoder_private;
239 Uint32 max = (internal->buffer_size < (Uint32) w->bytesLeft) ?
240 internal->buffer_size : (Uint32) w->bytesLeft;
241
242 assert(max > 0);
243
244 /*
245 * We don't actually do any decoding, so we read the wav data
246 * directly into the internal buffer...
247 */
248 retval = SDL_RWread(internal->rw, internal->buffer, 1, max);
249
250 w->bytesLeft -= retval;
251
252 /* Make sure the read went smoothly... */
253 if ((retval == 0) || (w->bytesLeft == 0))
254 sample->flags |= SOUND_SAMPLEFLAG_EOF;
255
256 else if (retval == -1)
257 sample->flags |= SOUND_SAMPLEFLAG_ERROR;
258
259 /* (next call this EAGAIN may turn into an EOF or error.) */
260 else if (retval < internal->buffer_size)
261 sample->flags |= SOUND_SAMPLEFLAG_EAGAIN;
262
263 return(retval);
264 } /* WAV_read */
265
266
267 /* end of wav.c ... */
268