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comparison decoders/voc.c @ 14:41e5e07c5fed

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Initial add.
author Ryan C. Gordon <icculus@icculus.org>
date Tue, 18 Sep 2001 11:01:48 +0000
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13:f2af6266775f 14:41e5e07c5fed
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 * VOC decoder for SDL_sound.
22 *
23 * This driver handles Creative Labs VOC audio data...this is a legacy format,
24 * but there's some game ports that could make use of such a decoder. Plus,
25 * VOC is fairly straightforward to decode, so this is a more complex, but
26 * still palatable example of an SDL_sound decoder. Y'know, in case the
27 * RAW decoder didn't do it for you. :)
28 *
29 * This code was ripped from a decoder I had written for SDL_mixer, which was
30 * largely ripped from sox v12.17.1's voc.c.
31 *
32 * SDL_mixer: http://www.libsdl.org/projects/SDL_mixer/
33 * sox: http://www.freshmeat.net/projects/sox/
34 *
35 * Please see the file LICENSE in the source's root directory.
36 *
37 * This file written by Ryan C. Gordon. (icculus@clutteredmind.org)
38 */
39
40 #include <stdio.h>
41 #include <stdlib.h>
42 #include <string.h>
43 #include <assert.h>
44
45 #include "SDL.h"
46 #include "SDL_endian.h"
47 #include "SDL_sound.h"
48
49 #define __SDL_SOUND_INTERNAL__
50 #include "SDL_sound_internal.h"
51
52 #if (!defined SOUND_SUPPORTS_VOC)
53 #error SOUND_SUPPORTS_VOC must be defined.
54 #endif
55
56
57 static int VOC_open(Sound_Sample *sample, const char *ext);
58 static void VOC_close(Sound_Sample *sample);
59 static Uint32 VOC_read(Sound_Sample *sample);
60
61 const Sound_DecoderFunctions __Sound_DecoderFunctions_VOC =
62 {
63 {
64 "VOC",
65 "Creative Labs Voice format",
66 "Ryan C. Gordon <icculus@clutteredmind.org>",
67 "http://www.icculus.org/SDL_sound/"
68 },
69
70 VOC_open, /* open() method */
71 VOC_close, /* close() method */
72 VOC_read /* read() method */
73 };
74
75
76 /* Private data for VOC file */
77 typedef struct vocstuff {
78 Uint32 rest; /* bytes remaining in current block */
79 Uint32 rate; /* rate code (byte) of this chunk */
80 int silent; /* sound or silence? */
81 Uint32 srate; /* rate code (byte) of silence */
82 Uint32 blockseek; /* start of current output block */
83 Uint32 samples; /* number of samples output */
84 Uint32 size; /* word length of data */
85 int channels; /* number of sound channels */
86 int extended; /* Has an extended block been read? */
87 Uint32 bufpos; /* byte position in internal->buffer. */
88 } vs_t;
89
90 /* Size field */
91 /* SJB: note that the 1st 3 are sometimes used as sizeof(type) */
92 #define ST_SIZE_BYTE 1
93 #define ST_SIZE_8BIT 1
94 #define ST_SIZE_WORD 2
95 #define ST_SIZE_16BIT 2
96 #define ST_SIZE_DWORD 4
97 #define ST_SIZE_32BIT 4
98 #define ST_SIZE_FLOAT 5
99 #define ST_SIZE_DOUBLE 6
100 #define ST_SIZE_IEEE 7 /* IEEE 80-bit floats. */
101
102 /* Style field */
103 #define ST_ENCODING_UNSIGNED 1 /* unsigned linear: Sound Blaster */
104 #define ST_ENCODING_SIGN2 2 /* signed linear 2's comp: Mac */
105 #define ST_ENCODING_ULAW 3 /* U-law signed logs: US telephony, SPARC */
106 #define ST_ENCODING_ALAW 4 /* A-law signed logs: non-US telephony */
107 #define ST_ENCODING_ADPCM 5 /* Compressed PCM */
108 #define ST_ENCODING_IMA_ADPCM 6 /* Compressed PCM */
109 #define ST_ENCODING_GSM 7 /* GSM 6.10 33-byte frame lossy compression */
110
111 #define VOC_TERM 0
112 #define VOC_DATA 1
113 #define VOC_CONT 2
114 #define VOC_SILENCE 3
115 #define VOC_MARKER 4
116 #define VOC_TEXT 5
117 #define VOC_LOOP 6
118 #define VOC_LOOPEND 7
119 #define VOC_EXTENDED 8
120 #define VOC_DATA_16 9
121
122
123 static __inline__ int voc_check_header(SDL_RWops *src)
124 {
125 /* VOC magic header */
126 Uint8 signature[20]; /* "Creative Voice File\032" */
127 Uint16 datablockofs;
128
129 if (SDL_RWread(src, signature, sizeof (signature), 1) != 1)
130 return(0);
131
132 if (memcmp(signature, "Creative Voice File\032", sizeof (signature)) != 0) {
133 Sound_SetError("Unrecognized file type (not VOC)");
134 return(0);
135 }
136
137 /* get the offset where the first datablock is located */
138 if (SDL_RWread(src, &datablockofs, sizeof (Uint16), 1) != 1)
139 return(0);
140
141 datablockofs = SDL_SwapLE16(datablockofs);
142
143 if (SDL_RWseek(src, datablockofs, SEEK_SET) != datablockofs)
144 return(0);
145
146 return(1); /* success! */
147 } /* voc_check_header */
148
149 /* !!! FIXME : Add a flag to vs_t that distinguishes EOF and Error conditions. */
150
151 /* Read next block header, save info, leave position at start of data */
152 static int voc_get_block(Sound_Sample *sample)
153 {
154 Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;
155 SDL_RWops *src = internal->rw;
156 vs_t *v = (vs_t *) internal->decoder_private;
157 Uint8 bits24[3];
158 Uint8 uc, block;
159 Uint32 sblen;
160 Uint16 new_rate_short;
161 Uint32 new_rate_long;
162 Uint8 trash[6];
163 Uint16 period;
164 int i;
165
166 v->silent = 0;
167 while (v->rest == 0)
168 {
169 if (SDL_RWread(src, &block, sizeof (block), 1) != 1)
170 return 1; /* assume that's the end of the file. */
171
172 if (block == VOC_TERM)
173 return 1;
174
175 if (SDL_RWread(src, bits24, sizeof (bits24), 1) != 1)
176 return 1; /* assume that's the end of the file. */
177
178 /* Size is an 24-bit value. Ugh. */
179 sblen = ( (bits24[0]) | (bits24[1] << 8) | (bits24[2] << 16) );
180
181 switch(block)
182 {
183 case VOC_DATA:
184 if (SDL_RWread(src, &uc, sizeof (uc), 1) != 1)
185 return 0;
186
187 /* When DATA block preceeded by an EXTENDED */
188 /* block, the DATA blocks rate value is invalid */
189 if (!v->extended)
190 {
191 if (uc == 0)
192 {
193 Sound_SetError("VOC Sample rate is zero?");
194 return 0;
195 }
196
197 if ((v->rate != -1) && (uc != v->rate))
198 {
199 Sound_SetError("VOC sample rate codes differ");
200 return 0;
201 }
202
203 v->rate = uc;
204 sample->actual.rate = 1000000.0/(256 - v->rate);
205 v->channels = 1;
206 }
207
208 if (SDL_RWread(src, &uc, sizeof (uc), 1) != 1)
209 return 0;
210
211 if (uc != 0)
212 {
213 Sound_SetError("VOC decoder only interprets 8-bit data");
214 return 0;
215 }
216
217 v->extended = 0;
218 v->rest = sblen - 2;
219 v->size = ST_SIZE_BYTE;
220 return 1;
221
222 case VOC_DATA_16:
223 if (SDL_RWread(src, &new_rate_long, sizeof (new_rate_long), 1) != 1)
224 return 0;
225 new_rate_long = SDL_SwapLE32(new_rate_long);
226 if (new_rate_long == 0)
227 {
228 Sound_SetError("VOC Sample rate is zero?");
229 return 0;
230 }
231 if ((v->rate != -1) && (new_rate_long != v->rate))
232 {
233 Sound_SetError("VOC sample rate codes differ");
234 return 0;
235 }
236 v->rate = new_rate_long;
237 sample->actual.rate = new_rate_long;
238
239 if (SDL_RWread(src, &uc, sizeof (uc), 1) != 1)
240 return 0;
241
242 switch (uc)
243 {
244 case 8: v->size = ST_SIZE_BYTE; break;
245 case 16: v->size = ST_SIZE_WORD; break;
246 default:
247 Sound_SetError("VOC with unknown data size");
248 return 0;
249 }
250
251 if (SDL_RWread(src, &v->channels, sizeof (Uint8), 1) != 1)
252 return 0;
253
254 if (SDL_RWread(src, trash, sizeof (Uint8), 6) != 6)
255 return 0;
256
257 v->rest = sblen - 12;
258 return 1;
259
260 case VOC_CONT:
261 v->rest = sblen;
262 return 1;
263
264 case VOC_SILENCE:
265 if (SDL_RWread(src, &period, sizeof (period), 1) != 1)
266 return 0;
267 period = SDL_SwapLE16(period);
268
269 if (SDL_RWread(src, &uc, sizeof (uc), 1) != 1)
270 return 0;
271 if (uc == 0)
272 {
273 Sound_SetError("VOC silence sample rate is zero");
274 return 0;
275 }
276
277 /*
278 * Some silence-packed files have gratuitously
279 * different sample rate codes in silence.
280 * Adjust period.
281 */
282 if ((v->rate != -1) && (uc != v->rate))
283 period = (period * (256 - uc))/(256 - v->rate);
284 else
285 v->rate = uc;
286 v->rest = period;
287 v->silent = 1;
288 return 1;
289
290 case VOC_LOOP:
291 case VOC_LOOPEND:
292 for(i = 0; i < sblen; i++) /* skip repeat loops. */
293 {
294 if (SDL_RWread(src, trash, sizeof (Uint8), 1) != 1)
295 return 0;
296 }
297 break;
298
299 case VOC_EXTENDED:
300 /* An Extended block is followed by a data block */
301 /* Set this byte so we know to use the rate */
302 /* value from the extended block and not the */
303 /* data block. */
304 v->extended = 1;
305 if (SDL_RWread(src, &new_rate_short, sizeof (new_rate_short), 1) != 1)
306 return 0;
307 new_rate_short = SDL_SwapLE16(new_rate_short);
308 if (new_rate_short == 0)
309 {
310 Sound_SetError("VOC sample rate is zero");
311 return 0;
312 }
313 if ((v->rate != -1) && (new_rate_short != v->rate))
314 {
315 Sound_SetError("VOC sample rate codes differ");
316 return 0;
317 }
318 v->rate = new_rate_short;
319
320 if (SDL_RWread(src, &uc, sizeof (uc), 1) != 1)
321 return 0;
322
323 if (uc != 0)
324 {
325 Sound_SetError("VOC decoder only interprets 8-bit data");
326 return 0;
327 }
328
329 if (SDL_RWread(src, &uc, sizeof (uc), 1) != 1)
330 return 0;
331
332 if (uc)
333 sample->actual.channels = 2; /* Stereo */
334 /* Needed number of channels before finishing
335 compute for rate */
336 sample->actual.rate =
337 (256000000L/(65536L - v->rate)) / sample->actual.channels;
338 /* An extended block must be followed by a data */
339 /* block to be valid so loop back to top so it */
340 /* can be grabed. */
341 continue;
342
343 case VOC_MARKER:
344 if (SDL_RWread(src, trash, sizeof (Uint8), 2) != 2)
345 return 0;
346
347 /* Falling! Falling! */
348
349 default: /* text block or other krapola. */
350 for(i = 0; i < sblen; i++)
351 {
352 if (SDL_RWread(src, &trash, sizeof (Uint8), 1) != 1)
353 return 0;
354 }
355
356 if (block == VOC_TEXT)
357 continue; /* get next block */
358 }
359 }
360
361 return 1;
362 }
363
364
365 static int voc_read(Sound_Sample *sample)
366 {
367 Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;
368 SDL_RWops *src = internal->rw;
369 vs_t *v = (vs_t *) internal->decoder_private;
370 int done = 0;
371 Uint8 silence = 0x80;
372 Uint8 *buf = internal->buffer;
373
374 if (v->rest == 0)
375 {
376 if (!voc_get_block(sample))
377 return 0;
378 }
379
380 if (v->rest == 0)
381 return 0;
382
383 if (v->silent)
384 {
385 if (v->size == ST_SIZE_WORD)
386 silence = 0x00;
387
388 /* Fill in silence */
389 memset(buf, silence, v->rest);
390 done = v->rest;
391 v->rest = 0;
392 }
393
394 else
395 {
396 Uint32 max = (v->rest < internal->buffer_size) ?
397 v->rest : internal->buffer_size;
398 done = SDL_RWread(src, buf + v->bufpos, 1, max);
399 v->rest -= done;
400 v->bufpos += done;
401 if (v->size == ST_SIZE_WORD)
402 {
403 #if (SDL_BYTEORDER == SDL_BIG_ENDIAN)
404 for (; v->rest > 0; v->rest -= 2)
405 {
406 *((Uint16 *) buf) = SDL_SwapLE16(*((Uint16 *) buf));
407 ((Uint16 *) buf)++;
408 }
409 #endif
410 }
411 }
412
413 return done;
414 } /* voc_read */
415
416
417 static int VOC_open(Sound_Sample *sample, const char *ext)
418 {
419 Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;
420 vs_t *v = NULL;
421
422 if (!voc_check_header(internal->rw))
423 return(0);
424
425 v = (vs_t *) malloc(sizeof (vs_t));
426 BAIL_IF_MACRO(v == NULL, ERR_OUT_OF_MEMORY, 0);
427 memset(v, '\0', sizeof (vs_t));
428 internal->decoder_private = v;
429
430 v->rate = -1;
431 if (!voc_get_block(sample))
432 {
433 free(v);
434 return(0);
435 } /* if */
436
437 if (v->rate == -1)
438 {
439 Sound_SetError("VOC data had no sound!");
440 free(v);
441 return(0);
442 } /* if */
443
444 _D(("VOC: Accepting data stream.\n"));
445 sample->actual.format = (v->size == ST_SIZE_WORD) ? AUDIO_S16LSB:AUDIO_U8;
446 sample->actual.channels = v->channels;
447 sample->flags = SOUND_SAMPLEFLAG_NONE;
448 return(1);
449 } /* VOC_open */
450
451
452 static void VOC_close(Sound_Sample *sample)
453 {
454 Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;
455 free(internal->decoder_private);
456 } /* VOC_close */
457
458
459 static Uint32 VOC_read(Sound_Sample *sample)
460 {
461 Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;
462 vs_t *v = (vs_t *) internal->decoder_private;
463
464 v->bufpos = 0;
465 while (v->bufpos < internal->buffer_size)
466 {
467 Uint32 rc = voc_read(sample);
468 if (rc == 0) /* !!! FIXME: Could be an error... */
469 {
470 sample->flags |= SOUND_SAMPLEFLAG_EOF;
471 break;
472 } /* if */
473
474 if (!voc_get_block(sample))
475 {
476 sample->flags |= SOUND_SAMPLEFLAG_ERROR;
477 break;
478 } /* if */
479 } /* while */
480
481 return(v->bufpos);
482 } /* VOC_read */
483
484
485 /* end of voc.c ... */
486