afh: Expand documentation of init function declarations.
[paraslash.git] / afh_common.c
1 /*
2 * Copyright (C) 1997 Andre Noll <maan@tuebingen.mpg.de>
3 *
4 * Licensed under the GPL v2. For licencing details see COPYING.
5 */
6
7 /** \file afh_common.c Common audio format handler functions. */
8
9 #include <sys/mman.h> /* mmap */
10 #include <sys/types.h>
11 #include <regex.h>
12
13 #include "para.h"
14 #include "error.h"
15 #include "string.h"
16 #include "afh.h"
17
18 typedef void afh_init_func(struct audio_format_handler *);
19 /*
20 * Declaration of the audio format handler init functions.
21 *
22 * These symbols are referenced in the afl array below.
23 *
24 * Most audio format handlers depend on an external library and are not
25 * compiled in if the library is not installed. Hence it is well possible that
26 * not all of these functions are defined. It does not hurt to declare them
27 * anyway, and this avoids another set of ifdefs.
28 */
29 extern afh_init_func mp3_init, ogg_init, aac_afh_init, wma_afh_init,
30 spx_afh_init, flac_afh_init, opus_afh_init;
31
32 /** The list of all status items */
33 const char *status_item_list[] = {STATUS_ITEM_ARRAY};
34
35 /**
36 * The list of supported audio formats.
37 *
38 * We always define the full array of audio formats even if some audio formats
39 * were not compiled in. This is because for each audio file the number of its
40 * audio format is stored in the database. We don't want that numbers to become
41 * stale just because the user installed a new version of paraslash that
42 * supports a different set of audio formats.
43 *
44 * It can still be easily detected whether an audio format is compiled in by
45 * checking if the init function pointer is not \p NULL.
46 */
47 static struct audio_format_handler afl[] = {
48 {
49 .name = "mp3",
50 .init = mp3_init,
51 },
52 {
53 .name = "ogg",
54 #if defined(HAVE_OGG) && defined(HAVE_VORBIS)
55 .init = ogg_init,
56 #endif
57 },
58 {
59 .name = "aac",
60 #if defined(HAVE_FAAD)
61 .init = aac_afh_init,
62 #endif
63 },
64 {
65 .name = "wma",
66 .init = wma_afh_init,
67 },
68 {
69 .name = "spx",
70 #if defined(HAVE_OGG) && defined(HAVE_SPEEX)
71 .init = spx_afh_init,
72 #endif
73 },
74 {
75 .name = "flac",
76 #if defined(HAVE_OGG) && defined(HAVE_FLAC)
77 .init = flac_afh_init,
78 #endif
79 },
80 {
81 .name = "opus",
82 #if defined(HAVE_OGG) && defined(HAVE_OPUS)
83 .init = opus_afh_init,
84 #endif
85 },
86 {
87 .name = NULL,
88 }
89 };
90
91 static inline int next_audio_format(int format)
92 {
93 for (;;) {
94 if (!afl[format].name)
95 return format;
96 format++;
97 if (afl[format].init)
98 return format;
99 }
100 }
101
102 /** Iterate over each supported audio format. */
103 #define FOR_EACH_AUDIO_FORMAT(i) for (i = 0; afl[i].name; i = next_audio_format(i))
104
105 /**
106 * Call the init function of each supported audio format handler.
107 */
108 void afh_init(void)
109 {
110 int i;
111
112 PARA_NOTICE_LOG("supported audio formats: %s\n", AUDIO_FORMAT_HANDLERS);
113 FOR_EACH_AUDIO_FORMAT(i) {
114 PARA_INFO_LOG("initializing %s handler\n",
115 audio_format_name(i));
116 afl[i].init(&afl[i]);
117 }
118 }
119
120 /**
121 * Tell whether an audio format handler provides chunk tables.
122 *
123 * Each audio format handler either provides a chunk table or supports dynamic
124 * chunks.
125 *
126 * \param audio_format_id Offset in the afl array.
127 *
128 * \return True if dynamic chunks are supported, false if the audio format
129 * handler provides chunk tables.
130 */
131 bool afh_supports_dynamic_chunks(int audio_format_id)
132 {
133 return afl[audio_format_id].get_chunk;
134 }
135
136 /**
137 * Guess the audio format judging from filename.
138 *
139 * \param name The filename.
140 *
141 * \return This function returns \p -E_AUDIO_FORMAT if it has no idea what kind
142 * of audio file this might be. Otherwise the (non-negative) number of the
143 * audio format is returned.
144 */
145 int guess_audio_format(const char *name)
146 {
147 int i,j, len = strlen(name);
148
149 FOR_EACH_AUDIO_FORMAT(i) {
150 for (j = 0; afl[i].suffixes[j]; j++) {
151 const char *p = afl[i].suffixes[j];
152 int plen = strlen(p);
153 if (len < plen + 1)
154 continue;
155 if (name[len - plen - 1] != '.')
156 continue;
157 if (strcasecmp(name + len - plen, p))
158 continue;
159 // PARA_DEBUG_LOG("might be %s\n", audio_format_name(i));
160 return i;
161 }
162 }
163 return -E_AUDIO_FORMAT;
164 }
165
166 /**
167 * Get the name of the given audio format.
168 *
169 * \param i The audio format number.
170 *
171 * \return This returns a pointer to statically allocated memory so it
172 * must not be freed by the caller.
173 */
174 const char *audio_format_name(int i)
175 {
176 if (i < 0 || i >= ARRAY_SIZE(afl) - 1)
177 return "???";
178 return afl[i].name;
179 }
180
181 static int get_file_info(int format, const char *path, char *data,
182 size_t size, int fd, struct afh_info *afhi)
183 {
184 int ret;
185 const char *fmt = audio_format_name(format);
186
187 memset(afhi, 0, sizeof(*afhi));
188 ret = afl[format].get_file_info(data, size, fd, afhi);
189 if (ret < 0) {
190 PARA_WARNING_LOG("%s: %s format not detected: %s\n",
191 path, fmt, para_strerror(-ret));
192 return ret;
193 }
194 PARA_NOTICE_LOG("%s: detected %s format\n", path, fmt);
195 return format;
196 }
197
198 /**
199 * Call get_file_info() to obtain an afhi structure.
200 *
201 * \param path The full path of the audio file.
202 * \param data Pointer to the contents of the (mapped) file.
203 * \param size The file size in bytes.
204 * \param fd The open file descriptor.
205 * \param afhi Result pointer.
206 *
207 * \return The number of the audio format on success, \p -E_AUDIO_FORMAT if no
208 * compiled in audio format handler is able to handler the file.
209 *
210 * This function tries to find an audio format handler that can interpret the
211 * file given by \a data and \a size.
212 *
213 * It first tries to determine the audio format from the filename given by \a
214 * path. If this doesn't work, all other audio format handlers are tried until
215 * one is found that can handle the file.
216 */
217 int compute_afhi(const char *path, char *data, size_t size, int fd,
218 struct afh_info *afhi)
219 {
220 int ret, i, format;
221
222 format = guess_audio_format(path);
223 if (format >= 0) {
224 ret = get_file_info(format, path, data, size, fd, afhi);
225 if (ret >= 0)
226 goto success;
227 }
228 FOR_EACH_AUDIO_FORMAT(i) {
229 if (i == format) /* we already tried this one to no avail */
230 continue;
231 ret = get_file_info(i, path, data, size, fd, afhi);
232 if (ret >= 0)
233 goto success;
234 }
235 return -E_AUDIO_FORMAT;
236 success:
237 if (!afhi->techinfo)
238 afhi->techinfo = para_strdup(NULL);
239 if (!afhi->tags.artist)
240 afhi->tags.artist = para_strdup(NULL);
241 if (!afhi->tags.title)
242 afhi->tags.title = para_strdup(NULL);
243 if (!afhi->tags.year)
244 afhi->tags.year = para_strdup(NULL);
245 if (!afhi->tags.album)
246 afhi->tags.album = para_strdup(NULL);
247 if (!afhi->tags.comment)
248 afhi->tags.comment = para_strdup(NULL);
249 PARA_DEBUG_LOG("techinfo: %s\n", afhi->techinfo);
250 PARA_DEBUG_LOG("artist: %s\n", afhi->tags.artist);
251 PARA_DEBUG_LOG("title: %s\n", afhi->tags.title);
252 PARA_DEBUG_LOG("year: %s\n", afhi->tags.year);
253 PARA_DEBUG_LOG("album: %s\n", afhi->tags.album);
254 PARA_DEBUG_LOG("comment: %s\n", afhi->tags.comment);
255 return ret;
256 }
257
258 /**
259 * Deallocate the contents of an afh_info structure.
260 *
261 * \param afhi The structure to clear.
262 *
263 * This only frees the memory the various pointer fields of \a afhi point to.
264 * It does *not* free \a afhi itself.
265 */
266 void clear_afhi(struct afh_info *afhi)
267 {
268 if (!afhi)
269 return;
270 free(afhi->chunk_table);
271 free(afhi->techinfo);
272 free(afhi->tags.artist);
273 free(afhi->tags.title);
274 free(afhi->tags.year);
275 free(afhi->tags.album);
276 free(afhi->tags.comment);
277 }
278
279 static inline size_t get_chunk_len(long unsigned chunk_num,
280 const struct afh_info *afhi)
281 {
282 return afhi->chunk_table[chunk_num + 1] - afhi->chunk_table[chunk_num];
283 }
284
285 /**
286 * Get one chunk of audio data.
287 *
288 * This implicitly calls the ->open method of the audio format handler at the
289 * first call.
290 *
291 * \param chunk_num The number of the chunk to get.
292 * \param afhi Describes the audio file.
293 * \param audio_format_id Determines the afh.
294 * \param map The memory mapped audio file.
295 * \param mapsize Passed to the afh's ->open() method.
296 * \param buf Result pointer.
297 * \param len The length of the chunk in bytes.
298 * \param afh_context Value/result, determines whether ->open() is called.
299 *
300 * Upon return, \a buf will point so memory inside \a map. The returned buffer
301 * must therefore not be freed by the caller.
302 *
303 * \return Standard.
304 */
305 __must_check int afh_get_chunk(long unsigned chunk_num, struct afh_info *afhi,
306 uint8_t audio_format_id, const void *map, size_t mapsize,
307 const char **buf, size_t *len, void **afh_context)
308 {
309 struct audio_format_handler *afh = afl + audio_format_id;
310
311 if (afh_supports_dynamic_chunks(audio_format_id)) {
312 int ret;
313
314 if (!*afh_context) {
315 ret = afh->open(map, mapsize, afh_context);
316 if (ret < 0)
317 return ret;
318 }
319 ret = afl[audio_format_id].get_chunk(chunk_num, *afh_context,
320 buf, len);
321 if (ret < 0) {
322 afh->close(*afh_context);
323 *afh_context = NULL;
324 }
325 return ret;
326 } else {
327 size_t pos = afhi->chunk_table[chunk_num];
328 *buf = map + pos;
329 *len = get_chunk_len(chunk_num, afhi);
330 return 0;
331 }
332 }
333
334 /**
335 * Deallocate resources allocated due to dynamic chunk handling.
336 *
337 * This function should be called if afh_get_chunk() was called at least once.
338 * It is OK to call it even for audio formats which do not support dynamic
339 * chunks, in which case the function does nothing.
340 *
341 * \param afh_context As returned from the ->open method of the afh.
342 * \param audio_format_id Determines the afh.
343 */
344 void afh_close(void *afh_context, uint8_t audio_format_id)
345 {
346 struct audio_format_handler *afh = afl + audio_format_id;
347
348 if (!afh_supports_dynamic_chunks(audio_format_id))
349 return;
350 if (!afh->close)
351 return;
352 if (!afh_context)
353 return;
354 afh->close(afh_context);
355 }
356
357 /**
358 * Find a suitable start chunk.
359 *
360 * \param approx_chunk_num Upper bound for the chunk number to return.
361 * \param afhi Needed for the chunk table.
362 * \param audio_format_id Determines the afh.
363 *
364 * \return For audio format handlers which support dynamic chunks, the function
365 * returns the given chunk number. Otherwise it returns the first non-empty
366 * chunk <= \a approx_chunk_num.
367 *
368 * \sa \ref afh_get_chunk().
369 */
370 int32_t afh_get_start_chunk(int32_t approx_chunk_num,
371 const struct afh_info *afhi, uint8_t audio_format_id)
372 {
373 int32_t k;
374
375 if (afh_supports_dynamic_chunks(audio_format_id))
376 return approx_chunk_num;
377
378 for (k = PARA_MAX(0, approx_chunk_num); k >= 0; k--)
379 if (get_chunk_len(k, afhi) > 0)
380 return k;
381 return 0;
382 }
383
384 /**
385 * Get the header of an audio file.
386 *
387 * \param afhi The audio file handler data describing the file.
388 * \param audio_format_id Determines the audio format handler.
389 * \param map The data of the audio file.
390 * \param mapsize The amount of bytes of the mmapped audio file.
391 * \param buf The length of the header is stored here.
392 * \param len Points to a buffer containing the header on return.
393 *
394 * This function sets \a buf to \p NULL and \a len to zero if \a map or \a
395 * afhi is \p NULL, or if the current audio format does not need special
396 * header treatment.
397 *
398 * Otherwise, it is checked whether the audio format handler given by
399 * \a audio_format_id defines a ->get_header() method. If it does, this
400 * method is called to obtain the header. If ->get_header() is \p NULL,
401 * a reference to the first chunk of the audio file is returned.
402 *
403 * Once the header is no longer needed, the caller must call \ref
404 * afh_free_header() to free the resources allocated by this function.
405 */
406 void afh_get_header(struct afh_info *afhi, uint8_t audio_format_id,
407 void *map, size_t mapsize, char **buf, size_t *len)
408 {
409 struct audio_format_handler *afh = afl + audio_format_id;
410
411 if (!map || !afhi || !afhi->header_len) {
412 *buf = NULL;
413 *len = 0;
414 return;
415 }
416 if (!afh->get_header) {
417 *len = afhi->header_len;
418 *buf = map;
419 return;
420 }
421 afh->get_header(map, mapsize, buf, len);
422 }
423
424 /**
425 * Deallocate any resources obtained from afh_get_header().
426 *
427 * \param header_buf Pointer obtained via afh_get_header().
428 * \param audio_format_id Determines the audio format handler.
429 */
430 void afh_free_header(char *header_buf, uint8_t audio_format_id)
431 {
432 struct audio_format_handler *afh = afl + audio_format_id;
433
434 if (afh->get_header)
435 free(header_buf);
436 }
437
438 /**
439 * Pretty-print the contents of a struct afh_info into a buffer.
440 *
441 * \param audio_format_num The audio format number.
442 * \param afhi Pointer to the structure that contains the information.
443 * \param result Pretty-printed ahfi is here after the call.
444 *
445 * The \a result buffer is dynamically allocated and should be freed by the
446 * caller.
447 *
448 * \return The number of bytes. This function never fails.
449 */
450 unsigned afh_get_afhi_txt(int audio_format_num, struct afh_info *afhi, char **result)
451 {
452 return xasprintf(result, "%s: %dkbit/s\n" /* bitrate */
453 "%s: %s\n" /* format */
454 "%s: %dHz\n" /* frequency */
455 "%s: %d\n" /* channels */
456 "%s: %" PRIu32 "\n" /* seconds total */
457 "%s: %lu: %lu\n" /* chunk time */
458 "%s: %" PRIu32 "\n" /* num chunks */
459 "%s: %" PRIu32 "\n" /* max chunk size */
460 "%s: %s\n" /* techinfo */
461 "%s: %s\n" /* artist */
462 "%s: %s\n" /* title */
463 "%s: %s\n" /* year */
464 "%s: %s\n" /* album */
465 "%s: %s\n", /* comment */
466 status_item_list[SI_BITRATE], afhi->bitrate,
467 status_item_list[SI_FORMAT], audio_format_name(audio_format_num),
468 status_item_list[SI_FREQUENCY], afhi->frequency,
469 status_item_list[SI_CHANNELS], afhi->channels,
470 status_item_list[SI_SECONDS_TOTAL], afhi->seconds_total,
471 status_item_list[SI_CHUNK_TIME], (long unsigned)afhi->chunk_tv.tv_sec,
472 (long unsigned)afhi->chunk_tv.tv_usec,
473 status_item_list[SI_NUM_CHUNKS], afhi->chunks_total,
474 status_item_list[SI_MAX_CHUNK_SIZE], afhi->max_chunk_size,
475 status_item_list[SI_TECHINFO], afhi->techinfo? afhi->techinfo : "",
476 status_item_list[SI_ARTIST], afhi->tags.artist? afhi->tags.artist : "",
477 status_item_list[SI_TITLE], afhi->tags.title? afhi->tags.title : "",
478 status_item_list[SI_YEAR], afhi->tags.year? afhi->tags.year : "",
479 status_item_list[SI_ALBUM], afhi->tags.album? afhi->tags.album : "",
480 status_item_list[SI_COMMENT], afhi->tags.comment? afhi->tags.comment : ""
481 );
482 }
483
484 /**
485 * Determine the maximal chunk size by investigating the chunk table.
486 *
487 * \param afhi Value/result.
488 *
489 * This function iterates over the chunk table and sets ->max_chunk_size
490 * accordingly. The function exists only for backward compatibility since as of
491 * version 0.6.0, para_server stores the maximal chunk size in its database.
492 * This function is only called if the database value is zero, indicating that
493 * the file was added by an older server version.
494 */
495 void set_max_chunk_size(struct afh_info *afhi)
496 {
497 uint32_t n, max = 0, old = 0;
498
499 for (n = 0; n <= afhi->chunks_total; n++) {
500 uint32_t val = afhi->chunk_table[n];
501 /*
502 * If the first chunk is the header, do not consider it for the
503 * calculation of the largest chunk size.
504 */
505 if (n == 0 || (n == 1 && afhi->header_len > 0)) {
506 old = val;
507 continue;
508 }
509 max = PARA_MAX(max, val - old);
510 old = val;
511 }
512 afhi->max_chunk_size = max;
513 }
514
515 /**
516 * Create a copy of the given file with altered meta tags.
517 *
518 * \param audio_format_id Specifies the audio format.
519 * \param map The (read-only) memory map of the input file.
520 * \param mapsize The size of the input file in bytes.
521 * \param tags The new tags.
522 * \param output_fd Altered file is created using this file descriptor.
523 * \param filename The name of the temporary output file.
524 *
525 * This calls the ->rewrite_tags method of the audio format handler associated
526 * with \a audio_format_id to create a copy of the memory-mapped file given
527 * by \a map and \a mapsize, but with altered tags according to \a tags. If
528 * the audio format handler for \a audio_format_id lacks this optional method,
529 * the function returns (the paraslash error code of) \p ENOTSUP.
530 *
531 * \return Standard.
532 */
533 int afh_rewrite_tags(int audio_format_id, void *map, size_t mapsize,
534 struct taginfo *tags, int output_fd, const char *filename)
535 {
536 struct audio_format_handler *afh = afl + audio_format_id;
537
538 if (!afh->rewrite_tags)
539 return -ERRNO_TO_PARA_ERROR(ENOTSUP);
540 return afh->rewrite_tags(map, mapsize, tags, output_fd, filename);
541 }