1 /* grabbag - Convenience lib for various routines common to several tools
2  * Copyright (C) 2002,2003,2004,2005,2006,2007  Josh Coalson
3  *
4  * This library is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU Lesser General Public
6  * License as published by the Free Software Foundation; either
7  * version 2.1 of the License, or (at your option) any later version.
8  *
9  * This library is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12  * Lesser General Public License for more details.
13  *
14  * You should have received a copy of the GNU Lesser General Public
15  * License along with this library; if not, write to the Free Software
16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
17  */
18 
19 #if HAVE_CONFIG_H
20 #  include <config.h>
21 #endif
22 
23 #include "share/grabbag.h"
24 #include "share/replaygain_analysis.h"
25 #include "FLAC/assert.h"
26 #include "FLAC/metadata.h"
27 #include "FLAC/stream_decoder.h"
28 #include <locale.h>
29 #include <math.h>
30 #include <stdio.h>
31 #include <stdlib.h>
32 #include <string.h>
33 #if defined _MSC_VER || defined __MINGW32__
34 #include <io.h> /* for chmod() */
35 #endif
36 #include <sys/stat.h> /* for stat(), maybe chmod() */
37 
38 #ifdef local_min
39 #undef local_min
40 #endif
41 #define local_min(a,b) ((a)<(b)?(a):(b))
42 
43 #ifdef local_max
44 #undef local_max
45 #endif
46 #define local_max(a,b) ((a)>(b)?(a):(b))
47 
48 static const char *reference_format_ = "%s=%2.1f dB";
49 static const char *gain_format_ = "%s=%+2.2f dB";
50 static const char *peak_format_ = "%s=%1.8f";
51 
52 static double album_peak_, title_peak_;
53 
54 const unsigned GRABBAG__REPLAYGAIN_MAX_TAG_SPACE_REQUIRED = 190;
55 /*
56 	FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN/8 + 29 + 1 + 8 +
57 	FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN/8 + 21 + 1 + 10 +
58 	FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN/8 + 21 + 1 + 12 +
59 	FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN/8 + 21 + 1 + 10 +
60 	FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN/8 + 21 + 1 + 12
61 */
62 
63 const FLAC__byte * const GRABBAG__REPLAYGAIN_TAG_REFERENCE_LOUDNESS = (const FLAC__byte * const)"REPLAYGAIN_REFERENCE_LOUDNESS";
64 const FLAC__byte * const GRABBAG__REPLAYGAIN_TAG_TITLE_GAIN = (const FLAC__byte * const)"REPLAYGAIN_TRACK_GAIN";
65 const FLAC__byte * const GRABBAG__REPLAYGAIN_TAG_TITLE_PEAK = (const FLAC__byte * const)"REPLAYGAIN_TRACK_PEAK";
66 const FLAC__byte * const GRABBAG__REPLAYGAIN_TAG_ALBUM_GAIN = (const FLAC__byte * const)"REPLAYGAIN_ALBUM_GAIN";
67 const FLAC__byte * const GRABBAG__REPLAYGAIN_TAG_ALBUM_PEAK = (const FLAC__byte * const)"REPLAYGAIN_ALBUM_PEAK";
68 
69 
get_file_stats_(const char * filename,struct stat * stats)70 static FLAC__bool get_file_stats_(const char *filename, struct stat *stats)
71 {
72 	FLAC__ASSERT(0 != filename);
73 	FLAC__ASSERT(0 != stats);
74 	return (0 == stat(filename, stats));
75 }
76 
set_file_stats_(const char * filename,struct stat * stats)77 static void set_file_stats_(const char *filename, struct stat *stats)
78 {
79 	FLAC__ASSERT(0 != filename);
80 	FLAC__ASSERT(0 != stats);
81 
82 	(void)chmod(filename, stats->st_mode);
83 }
84 
append_tag_(FLAC__StreamMetadata * block,const char * format,const FLAC__byte * name,float value)85 static FLAC__bool append_tag_(FLAC__StreamMetadata *block, const char *format, const FLAC__byte *name, float value)
86 {
87 	char buffer[256];
88 	char *saved_locale;
89 	FLAC__StreamMetadata_VorbisComment_Entry entry;
90 
91 	FLAC__ASSERT(0 != block);
92 	FLAC__ASSERT(block->type == FLAC__METADATA_TYPE_VORBIS_COMMENT);
93 	FLAC__ASSERT(0 != format);
94 	FLAC__ASSERT(0 != name);
95 
96 	buffer[sizeof(buffer)-1] = '\0';
97 	/*
98 	 * We need to save the old locale and switch to "C" because the locale
99 	 * influences the formatting of %f and we want it a certain way.
100 	 */
101 	saved_locale = strdup(setlocale(LC_ALL, 0));
102 	if (0 == saved_locale)
103 		return false;
104 	setlocale(LC_ALL, "C");
105 #if defined _MSC_VER || defined __MINGW32__
106 	_snprintf(buffer, sizeof(buffer)-1, format, name, value);
107 #else
108 	snprintf(buffer, sizeof(buffer)-1, format, name, value);
109 #endif
110 	setlocale(LC_ALL, saved_locale);
111 	free(saved_locale);
112 
113 	entry.entry = (FLAC__byte *)buffer;
114 	entry.length = strlen(buffer);
115 
116 	return FLAC__metadata_object_vorbiscomment_append_comment(block, entry, /*copy=*/true);
117 }
118 
grabbag__replaygain_is_valid_sample_frequency(unsigned sample_frequency)119 FLAC__bool grabbag__replaygain_is_valid_sample_frequency(unsigned sample_frequency)
120 {
121 	static const unsigned valid_sample_rates[] = {
122 		8000,
123 		11025,
124 		12000,
125 		16000,
126 		22050,
127 		24000,
128 		32000,
129 		44100,
130 		48000
131 	};
132 	static const unsigned n_valid_sample_rates = sizeof(valid_sample_rates) / sizeof(valid_sample_rates[0]);
133 
134 	unsigned i;
135 
136 	for(i = 0; i < n_valid_sample_rates; i++)
137 		if(sample_frequency == valid_sample_rates[i])
138 			return true;
139 	return false;
140 }
141 
grabbag__replaygain_init(unsigned sample_frequency)142 FLAC__bool grabbag__replaygain_init(unsigned sample_frequency)
143 {
144 	title_peak_ = album_peak_ = 0.0;
145 	return InitGainAnalysis((long)sample_frequency) == INIT_GAIN_ANALYSIS_OK;
146 }
147 
grabbag__replaygain_analyze(const FLAC__int32 * const input[],FLAC__bool is_stereo,unsigned bps,unsigned samples)148 FLAC__bool grabbag__replaygain_analyze(const FLAC__int32 * const input[], FLAC__bool is_stereo, unsigned bps, unsigned samples)
149 {
150 	/* using a small buffer improves data locality; we'd like it to fit easily in the dcache */
151 	static Float_t lbuffer[2048], rbuffer[2048];
152 	static const unsigned nbuffer = sizeof(lbuffer) / sizeof(lbuffer[0]);
153 	FLAC__int32 block_peak = 0, s;
154 	unsigned i, j;
155 
156 	FLAC__ASSERT(bps >= 4 && bps <= FLAC__REFERENCE_CODEC_MAX_BITS_PER_SAMPLE);
157 	FLAC__ASSERT(FLAC__MIN_BITS_PER_SAMPLE == 4);
158 	/*
159 	 * We use abs() on a FLAC__int32 which is undefined for the most negative value.
160 	 * If the reference codec ever handles 32bps we will have to write a special
161 	 * case here.
162 	 */
163 	FLAC__ASSERT(FLAC__REFERENCE_CODEC_MAX_BITS_PER_SAMPLE < 32);
164 
165 	if(bps == 16) {
166 		if(is_stereo) {
167 			j = 0;
168 			while(samples > 0) {
169 				const unsigned n = local_min(samples, nbuffer);
170 				for(i = 0; i < n; i++, j++) {
171 					s = input[0][j];
172 					lbuffer[i] = (Float_t)s;
173 					s = abs(s);
174 					block_peak = local_max(block_peak, s);
175 
176 					s = input[1][j];
177 					rbuffer[i] = (Float_t)s;
178 					s = abs(s);
179 					block_peak = local_max(block_peak, s);
180 				}
181 				samples -= n;
182 				if(AnalyzeSamples(lbuffer, rbuffer, n, 2) != GAIN_ANALYSIS_OK)
183 					return false;
184 			}
185 		}
186 		else {
187 			j = 0;
188 			while(samples > 0) {
189 				const unsigned n = local_min(samples, nbuffer);
190 				for(i = 0; i < n; i++, j++) {
191 					s = input[0][j];
192 					lbuffer[i] = (Float_t)s;
193 					s = abs(s);
194 					block_peak = local_max(block_peak, s);
195 				}
196 				samples -= n;
197 				if(AnalyzeSamples(lbuffer, 0, n, 1) != GAIN_ANALYSIS_OK)
198 					return false;
199 			}
200 		}
201 	}
202 	else { /* bps must be < 32 according to above assertion */
203 		const double scale = (
204 			(bps > 16)?
205 				(double)1. / (double)(1u << (bps - 16)) :
206 				(double)(1u << (16 - bps))
207 		);
208 
209 		if(is_stereo) {
210 			j = 0;
211 			while(samples > 0) {
212 				const unsigned n = local_min(samples, nbuffer);
213 				for(i = 0; i < n; i++, j++) {
214 					s = input[0][j];
215 					lbuffer[i] = (Float_t)(scale * (double)s);
216 					s = abs(s);
217 					block_peak = local_max(block_peak, s);
218 
219 					s = input[1][j];
220 					rbuffer[i] = (Float_t)(scale * (double)s);
221 					s = abs(s);
222 					block_peak = local_max(block_peak, s);
223 				}
224 				samples -= n;
225 				if(AnalyzeSamples(lbuffer, rbuffer, n, 2) != GAIN_ANALYSIS_OK)
226 					return false;
227 			}
228 		}
229 		else {
230 			j = 0;
231 			while(samples > 0) {
232 				const unsigned n = local_min(samples, nbuffer);
233 				for(i = 0; i < n; i++, j++) {
234 					s = input[0][j];
235 					lbuffer[i] = (Float_t)(scale * (double)s);
236 					s = abs(s);
237 					block_peak = local_max(block_peak, s);
238 				}
239 				samples -= n;
240 				if(AnalyzeSamples(lbuffer, 0, n, 1) != GAIN_ANALYSIS_OK)
241 					return false;
242 			}
243 		}
244 	}
245 
246 	{
247 		const double peak_scale = (double)(1u << (bps - 1));
248 		double peak = (double)block_peak / peak_scale;
249 		if(peak > title_peak_)
250 			title_peak_ = peak;
251 		if(peak > album_peak_)
252 			album_peak_ = peak;
253 	}
254 
255 	return true;
256 }
257 
grabbag__replaygain_get_album(float * gain,float * peak)258 void grabbag__replaygain_get_album(float *gain, float *peak)
259 {
260 	*gain = (float)GetAlbumGain();
261 	*peak = (float)album_peak_;
262 	album_peak_ = 0.0;
263 }
264 
grabbag__replaygain_get_title(float * gain,float * peak)265 void grabbag__replaygain_get_title(float *gain, float *peak)
266 {
267 	*gain = (float)GetTitleGain();
268 	*peak = (float)title_peak_;
269 	title_peak_ = 0.0;
270 }
271 
272 
273 typedef struct {
274 	unsigned channels;
275 	unsigned bits_per_sample;
276 	unsigned sample_rate;
277 	FLAC__bool error;
278 } DecoderInstance;
279 
write_callback_(const FLAC__StreamDecoder * decoder,const FLAC__Frame * frame,const FLAC__int32 * const buffer[],void * client_data)280 static FLAC__StreamDecoderWriteStatus write_callback_(const FLAC__StreamDecoder *decoder, const FLAC__Frame *frame, const FLAC__int32 * const buffer[], void *client_data)
281 {
282 	DecoderInstance *instance = (DecoderInstance*)client_data;
283 	const unsigned bits_per_sample = frame->header.bits_per_sample;
284 	const unsigned channels = frame->header.channels;
285 	const unsigned sample_rate = frame->header.sample_rate;
286 	const unsigned samples = frame->header.blocksize;
287 
288 	(void)decoder;
289 
290 	if(
291 		!instance->error &&
292 		(channels == 2 || channels == 1) &&
293 		bits_per_sample == instance->bits_per_sample &&
294 		channels == instance->channels &&
295 		sample_rate == instance->sample_rate
296 	) {
297 		instance->error = !grabbag__replaygain_analyze(buffer, channels==2, bits_per_sample, samples);
298 	}
299 	else {
300 		instance->error = true;
301 	}
302 
303 	if(!instance->error)
304 		return FLAC__STREAM_DECODER_WRITE_STATUS_CONTINUE;
305 	else
306 		return FLAC__STREAM_DECODER_WRITE_STATUS_ABORT;
307 }
308 
metadata_callback_(const FLAC__StreamDecoder * decoder,const FLAC__StreamMetadata * metadata,void * client_data)309 static void metadata_callback_(const FLAC__StreamDecoder *decoder, const FLAC__StreamMetadata *metadata, void *client_data)
310 {
311 	DecoderInstance *instance = (DecoderInstance*)client_data;
312 
313 	(void)decoder;
314 
315 	if(metadata->type == FLAC__METADATA_TYPE_STREAMINFO) {
316 		instance->bits_per_sample = metadata->data.stream_info.bits_per_sample;
317 		instance->channels = metadata->data.stream_info.channels;
318 		instance->sample_rate = metadata->data.stream_info.sample_rate;
319 
320 		if(instance->channels != 1 && instance->channels != 2) {
321 			instance->error = true;
322 			return;
323 		}
324 
325 		if(!grabbag__replaygain_is_valid_sample_frequency(instance->sample_rate)) {
326 			instance->error = true;
327 			return;
328 		}
329 	}
330 }
331 
error_callback_(const FLAC__StreamDecoder * decoder,FLAC__StreamDecoderErrorStatus status,void * client_data)332 static void error_callback_(const FLAC__StreamDecoder *decoder, FLAC__StreamDecoderErrorStatus status, void *client_data)
333 {
334 	DecoderInstance *instance = (DecoderInstance*)client_data;
335 
336 	(void)decoder, (void)status;
337 
338 	instance->error = true;
339 }
340 
grabbag__replaygain_analyze_file(const char * filename,float * title_gain,float * title_peak)341 const char *grabbag__replaygain_analyze_file(const char *filename, float *title_gain, float *title_peak)
342 {
343 	DecoderInstance instance;
344 	FLAC__StreamDecoder *decoder = FLAC__stream_decoder_new();
345 
346 	if(0 == decoder)
347 		return "memory allocation error";
348 
349 	instance.error = false;
350 
351 	/* It does these three by default but lets be explicit: */
352 	FLAC__stream_decoder_set_md5_checking(decoder, false);
353 	FLAC__stream_decoder_set_metadata_ignore_all(decoder);
354 	FLAC__stream_decoder_set_metadata_respond(decoder, FLAC__METADATA_TYPE_STREAMINFO);
355 
356 	if(FLAC__stream_decoder_init_file(decoder, filename, write_callback_, metadata_callback_, error_callback_, &instance) != FLAC__STREAM_DECODER_INIT_STATUS_OK) {
357 		FLAC__stream_decoder_delete(decoder);
358 		return "initializing decoder";
359 	}
360 
361 	if(!FLAC__stream_decoder_process_until_end_of_stream(decoder) || instance.error) {
362 		FLAC__stream_decoder_delete(decoder);
363 		return "decoding file";
364 	}
365 
366 	FLAC__stream_decoder_delete(decoder);
367 
368 	grabbag__replaygain_get_title(title_gain, title_peak);
369 
370 	return 0;
371 }
372 
grabbag__replaygain_store_to_vorbiscomment(FLAC__StreamMetadata * block,float album_gain,float album_peak,float title_gain,float title_peak)373 const char *grabbag__replaygain_store_to_vorbiscomment(FLAC__StreamMetadata *block, float album_gain, float album_peak, float title_gain, float title_peak)
374 {
375 	const char *error;
376 
377 	if(0 != (error = grabbag__replaygain_store_to_vorbiscomment_reference(block)))
378 		return error;
379 
380 	if(0 != (error = grabbag__replaygain_store_to_vorbiscomment_title(block, title_gain, title_peak)))
381 		return error;
382 
383 	if(0 != (error = grabbag__replaygain_store_to_vorbiscomment_album(block, album_gain, album_peak)))
384 		return error;
385 
386 	return 0;
387 }
388 
grabbag__replaygain_store_to_vorbiscomment_reference(FLAC__StreamMetadata * block)389 const char *grabbag__replaygain_store_to_vorbiscomment_reference(FLAC__StreamMetadata *block)
390 {
391 	FLAC__ASSERT(0 != block);
392 	FLAC__ASSERT(block->type == FLAC__METADATA_TYPE_VORBIS_COMMENT);
393 
394 	if(FLAC__metadata_object_vorbiscomment_remove_entries_matching(block, (const char *)GRABBAG__REPLAYGAIN_TAG_REFERENCE_LOUDNESS) < 0)
395 		return "memory allocation error";
396 
397 	if(!append_tag_(block, reference_format_, GRABBAG__REPLAYGAIN_TAG_REFERENCE_LOUDNESS, ReplayGainReferenceLoudness))
398 		return "memory allocation error";
399 
400 	return 0;
401 }
402 
grabbag__replaygain_store_to_vorbiscomment_album(FLAC__StreamMetadata * block,float album_gain,float album_peak)403 const char *grabbag__replaygain_store_to_vorbiscomment_album(FLAC__StreamMetadata *block, float album_gain, float album_peak)
404 {
405 	FLAC__ASSERT(0 != block);
406 	FLAC__ASSERT(block->type == FLAC__METADATA_TYPE_VORBIS_COMMENT);
407 
408 	if(
409 		FLAC__metadata_object_vorbiscomment_remove_entries_matching(block, (const char *)GRABBAG__REPLAYGAIN_TAG_ALBUM_GAIN) < 0 ||
410 		FLAC__metadata_object_vorbiscomment_remove_entries_matching(block, (const char *)GRABBAG__REPLAYGAIN_TAG_ALBUM_PEAK) < 0
411 	)
412 		return "memory allocation error";
413 
414 	if(
415 		!append_tag_(block, gain_format_, GRABBAG__REPLAYGAIN_TAG_ALBUM_GAIN, album_gain) ||
416 		!append_tag_(block, peak_format_, GRABBAG__REPLAYGAIN_TAG_ALBUM_PEAK, album_peak)
417 	)
418 		return "memory allocation error";
419 
420 	return 0;
421 }
422 
grabbag__replaygain_store_to_vorbiscomment_title(FLAC__StreamMetadata * block,float title_gain,float title_peak)423 const char *grabbag__replaygain_store_to_vorbiscomment_title(FLAC__StreamMetadata *block, float title_gain, float title_peak)
424 {
425 	FLAC__ASSERT(0 != block);
426 	FLAC__ASSERT(block->type == FLAC__METADATA_TYPE_VORBIS_COMMENT);
427 
428 	if(
429 		FLAC__metadata_object_vorbiscomment_remove_entries_matching(block, (const char *)GRABBAG__REPLAYGAIN_TAG_TITLE_GAIN) < 0 ||
430 		FLAC__metadata_object_vorbiscomment_remove_entries_matching(block, (const char *)GRABBAG__REPLAYGAIN_TAG_TITLE_PEAK) < 0
431 	)
432 		return "memory allocation error";
433 
434 	if(
435 		!append_tag_(block, gain_format_, GRABBAG__REPLAYGAIN_TAG_TITLE_GAIN, title_gain) ||
436 		!append_tag_(block, peak_format_, GRABBAG__REPLAYGAIN_TAG_TITLE_PEAK, title_peak)
437 	)
438 		return "memory allocation error";
439 
440 	return 0;
441 }
442 
store_to_file_pre_(const char * filename,FLAC__Metadata_Chain ** chain,FLAC__StreamMetadata ** block)443 static const char *store_to_file_pre_(const char *filename, FLAC__Metadata_Chain **chain, FLAC__StreamMetadata **block)
444 {
445 	FLAC__Metadata_Iterator *iterator;
446 	const char *error;
447 	FLAC__bool found_vc_block = false;
448 
449 	if(0 == (*chain = FLAC__metadata_chain_new()))
450 		return "memory allocation error";
451 
452 	if(!FLAC__metadata_chain_read(*chain, filename)) {
453 		error = FLAC__Metadata_ChainStatusString[FLAC__metadata_chain_status(*chain)];
454 		FLAC__metadata_chain_delete(*chain);
455 		return error;
456 	}
457 
458 	if(0 == (iterator = FLAC__metadata_iterator_new())) {
459 		FLAC__metadata_chain_delete(*chain);
460 		return "memory allocation error";
461 	}
462 
463 	FLAC__metadata_iterator_init(iterator, *chain);
464 
465 	do {
466 		*block = FLAC__metadata_iterator_get_block(iterator);
467 		if((*block)->type == FLAC__METADATA_TYPE_VORBIS_COMMENT)
468 			found_vc_block = true;
469 	} while(!found_vc_block && FLAC__metadata_iterator_next(iterator));
470 
471 	if(!found_vc_block) {
472 		/* create a new block */
473 		*block = FLAC__metadata_object_new(FLAC__METADATA_TYPE_VORBIS_COMMENT);
474 		if(0 == *block) {
475 			FLAC__metadata_chain_delete(*chain);
476 			FLAC__metadata_iterator_delete(iterator);
477 			return "memory allocation error";
478 		}
479 		while(FLAC__metadata_iterator_next(iterator))
480 			;
481 		if(!FLAC__metadata_iterator_insert_block_after(iterator, *block)) {
482 			error = FLAC__Metadata_ChainStatusString[FLAC__metadata_chain_status(*chain)];
483 			FLAC__metadata_chain_delete(*chain);
484 			FLAC__metadata_iterator_delete(iterator);
485 			return error;
486 		}
487 		/* iterator is left pointing to new block */
488 		FLAC__ASSERT(FLAC__metadata_iterator_get_block(iterator) == *block);
489 	}
490 
491 	FLAC__metadata_iterator_delete(iterator);
492 
493 	FLAC__ASSERT(0 != *block);
494 	FLAC__ASSERT((*block)->type == FLAC__METADATA_TYPE_VORBIS_COMMENT);
495 
496 	return 0;
497 }
498 
store_to_file_post_(const char * filename,FLAC__Metadata_Chain * chain,FLAC__bool preserve_modtime)499 static const char *store_to_file_post_(const char *filename, FLAC__Metadata_Chain *chain, FLAC__bool preserve_modtime)
500 {
501 	struct stat stats;
502 	const FLAC__bool have_stats = get_file_stats_(filename, &stats);
503 
504 	(void)grabbag__file_change_stats(filename, /*read_only=*/false);
505 
506 	FLAC__metadata_chain_sort_padding(chain);
507 	if(!FLAC__metadata_chain_write(chain, /*use_padding=*/true, preserve_modtime)) {
508 		FLAC__metadata_chain_delete(chain);
509 		return FLAC__Metadata_ChainStatusString[FLAC__metadata_chain_status(chain)];
510 	}
511 
512 	FLAC__metadata_chain_delete(chain);
513 
514 	if(have_stats)
515 		set_file_stats_(filename, &stats);
516 
517 	return 0;
518 }
519 
grabbag__replaygain_store_to_file(const char * filename,float album_gain,float album_peak,float title_gain,float title_peak,FLAC__bool preserve_modtime)520 const char *grabbag__replaygain_store_to_file(const char *filename, float album_gain, float album_peak, float title_gain, float title_peak, FLAC__bool preserve_modtime)
521 {
522 	FLAC__Metadata_Chain *chain;
523 	FLAC__StreamMetadata *block;
524 	const char *error;
525 
526 	if(0 != (error = store_to_file_pre_(filename, &chain, &block)))
527 		return error;
528 
529 	if(0 != (error = grabbag__replaygain_store_to_vorbiscomment(block, album_gain, album_peak, title_gain, title_peak))) {
530 		FLAC__metadata_chain_delete(chain);
531 		return error;
532 	}
533 
534 	if(0 != (error = store_to_file_post_(filename, chain, preserve_modtime)))
535 		return error;
536 
537 	return 0;
538 }
539 
grabbag__replaygain_store_to_file_reference(const char * filename,FLAC__bool preserve_modtime)540 const char *grabbag__replaygain_store_to_file_reference(const char *filename, FLAC__bool preserve_modtime)
541 {
542 	FLAC__Metadata_Chain *chain;
543 	FLAC__StreamMetadata *block;
544 	const char *error;
545 
546 	if(0 != (error = store_to_file_pre_(filename, &chain, &block)))
547 		return error;
548 
549 	if(0 != (error = grabbag__replaygain_store_to_vorbiscomment_reference(block))) {
550 		FLAC__metadata_chain_delete(chain);
551 		return error;
552 	}
553 
554 	if(0 != (error = store_to_file_post_(filename, chain, preserve_modtime)))
555 		return error;
556 
557 	return 0;
558 }
559 
grabbag__replaygain_store_to_file_album(const char * filename,float album_gain,float album_peak,FLAC__bool preserve_modtime)560 const char *grabbag__replaygain_store_to_file_album(const char *filename, float album_gain, float album_peak, FLAC__bool preserve_modtime)
561 {
562 	FLAC__Metadata_Chain *chain;
563 	FLAC__StreamMetadata *block;
564 	const char *error;
565 
566 	if(0 != (error = store_to_file_pre_(filename, &chain, &block)))
567 		return error;
568 
569 	if(0 != (error = grabbag__replaygain_store_to_vorbiscomment_album(block, album_gain, album_peak))) {
570 		FLAC__metadata_chain_delete(chain);
571 		return error;
572 	}
573 
574 	if(0 != (error = store_to_file_post_(filename, chain, preserve_modtime)))
575 		return error;
576 
577 	return 0;
578 }
579 
grabbag__replaygain_store_to_file_title(const char * filename,float title_gain,float title_peak,FLAC__bool preserve_modtime)580 const char *grabbag__replaygain_store_to_file_title(const char *filename, float title_gain, float title_peak, FLAC__bool preserve_modtime)
581 {
582 	FLAC__Metadata_Chain *chain;
583 	FLAC__StreamMetadata *block;
584 	const char *error;
585 
586 	if(0 != (error = store_to_file_pre_(filename, &chain, &block)))
587 		return error;
588 
589 	if(0 != (error = grabbag__replaygain_store_to_vorbiscomment_title(block, title_gain, title_peak))) {
590 		FLAC__metadata_chain_delete(chain);
591 		return error;
592 	}
593 
594 	if(0 != (error = store_to_file_post_(filename, chain, preserve_modtime)))
595 		return error;
596 
597 	return 0;
598 }
599 
parse_double_(const FLAC__StreamMetadata_VorbisComment_Entry * entry,double * val)600 static FLAC__bool parse_double_(const FLAC__StreamMetadata_VorbisComment_Entry *entry, double *val)
601 {
602 	char s[32], *end;
603 	const char *p, *q;
604 	double v;
605 
606 	FLAC__ASSERT(0 != entry);
607 	FLAC__ASSERT(0 != val);
608 
609 	p = (const char *)entry->entry;
610 	q = strchr(p, '=');
611 	if(0 == q)
612 		return false;
613 	q++;
614 	memset(s, 0, sizeof(s)-1);
615 	strncpy(s, q, local_min(sizeof(s)-1, entry->length - (q-p)));
616 
617 	v = strtod(s, &end);
618 	if(end == s)
619 		return false;
620 
621 	*val = v;
622 	return true;
623 }
624 
grabbag__replaygain_load_from_vorbiscomment(const FLAC__StreamMetadata * block,FLAC__bool album_mode,FLAC__bool strict,double * reference,double * gain,double * peak)625 FLAC__bool grabbag__replaygain_load_from_vorbiscomment(const FLAC__StreamMetadata *block, FLAC__bool album_mode, FLAC__bool strict, double *reference, double *gain, double *peak)
626 {
627 	int reference_offset, gain_offset, peak_offset;
628 
629 	FLAC__ASSERT(0 != block);
630 	FLAC__ASSERT(0 != reference);
631 	FLAC__ASSERT(0 != gain);
632 	FLAC__ASSERT(0 != peak);
633 	FLAC__ASSERT(block->type == FLAC__METADATA_TYPE_VORBIS_COMMENT);
634 
635 	/* Default to current level until overridden by a detected tag; this
636 	 * will always be true until we change replaygain_analysis.c
637 	 */
638 	*reference = ReplayGainReferenceLoudness;
639 
640 	if(0 <= (reference_offset = FLAC__metadata_object_vorbiscomment_find_entry_from(block, /*offset=*/0, (const char *)GRABBAG__REPLAYGAIN_TAG_REFERENCE_LOUDNESS)))
641 		(void)parse_double_(block->data.vorbis_comment.comments + reference_offset, reference);
642 
643 	if(0 > (gain_offset = FLAC__metadata_object_vorbiscomment_find_entry_from(block, /*offset=*/0, (const char *)(album_mode? GRABBAG__REPLAYGAIN_TAG_ALBUM_GAIN : GRABBAG__REPLAYGAIN_TAG_TITLE_GAIN))))
644 		return !strict && grabbag__replaygain_load_from_vorbiscomment(block, !album_mode, /*strict=*/true, reference, gain, peak);
645 	if(0 > (peak_offset = FLAC__metadata_object_vorbiscomment_find_entry_from(block, /*offset=*/0, (const char *)(album_mode? GRABBAG__REPLAYGAIN_TAG_ALBUM_PEAK : GRABBAG__REPLAYGAIN_TAG_TITLE_PEAK))))
646 		return !strict && grabbag__replaygain_load_from_vorbiscomment(block, !album_mode, /*strict=*/true, reference, gain, peak);
647 
648 	if(!parse_double_(block->data.vorbis_comment.comments + gain_offset, gain))
649 		return !strict && grabbag__replaygain_load_from_vorbiscomment(block, !album_mode, /*strict=*/true, reference, gain, peak);
650 	if(!parse_double_(block->data.vorbis_comment.comments + peak_offset, peak))
651 		return !strict && grabbag__replaygain_load_from_vorbiscomment(block, !album_mode, /*strict=*/true, reference, gain, peak);
652 
653 	return true;
654 }
655 
grabbag__replaygain_compute_scale_factor(double peak,double gain,double preamp,FLAC__bool prevent_clipping)656 double grabbag__replaygain_compute_scale_factor(double peak, double gain, double preamp, FLAC__bool prevent_clipping)
657 {
658 	double scale;
659 	FLAC__ASSERT(peak >= 0.0);
660  	gain += preamp;
661 	scale = (float) pow(10.0, gain * 0.05);
662 	if(prevent_clipping && peak > 0.0) {
663 		const double max_scale = (float)(1.0 / peak);
664 		if(scale > max_scale)
665 			scale = max_scale;
666 	}
667 	return scale;
668 }
669