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1 /* libFLAC - Free Lossless Audio Codec library
2  * Copyright (C) 2000-2009  Josh Coalson
3  * Copyright (C) 2011-2016  Xiph.Org Foundation
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  *
9  * - Redistributions of source code must retain the above copyright
10  * notice, this list of conditions and the following disclaimer.
11  *
12  * - Redistributions in binary form must reproduce the above copyright
13  * notice, this list of conditions and the following disclaimer in the
14  * documentation and/or other materials provided with the distribution.
15  *
16  * - Neither the name of the Xiph.org Foundation nor the names of its
17  * contributors may be used to endorse or promote products derived from
18  * this software without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
23  * A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR
24  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
25  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
26  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
27  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
28  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
29  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
30  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31  */
32 
33 #ifndef FLAC__FORMAT_H
34 #define FLAC__FORMAT_H
35 
36 #include "export.h"
37 #include "ordinals.h"
38 
39 #ifdef __cplusplus
40 extern "C" {
41 #endif
42 
43 /** \file include/FLAC/format.h
44  *
45  *  \brief
46  *  This module contains structure definitions for the representation
47  *  of FLAC format components in memory.  These are the basic
48  *  structures used by the rest of the interfaces.
49  *
50  *  See the detailed documentation in the
51  *  \link flac_format format \endlink module.
52  */
53 
54 /** \defgroup flac_format FLAC/format.h: format components
55  *  \ingroup flac
56  *
57  *  \brief
58  *  This module contains structure definitions for the representation
59  *  of FLAC format components in memory.  These are the basic
60  *  structures used by the rest of the interfaces.
61  *
62  *  First, you should be familiar with the
63  *  <A HREF="../format.html">FLAC format</A>.  Many of the values here
64  *  follow directly from the specification.  As a user of libFLAC, the
65  *  interesting parts really are the structures that describe the frame
66  *  header and metadata blocks.
67  *
68  *  The format structures here are very primitive, designed to store
69  *  information in an efficient way.  Reading information from the
70  *  structures is easy but creating or modifying them directly is
71  *  more complex.  For the most part, as a user of a library, editing
72  *  is not necessary; however, for metadata blocks it is, so there are
73  *  convenience functions provided in the \link flac_metadata metadata
74  *  module \endlink to simplify the manipulation of metadata blocks.
75  *
76  * \note
77  * It's not the best convention, but symbols ending in _LEN are in bits
78  * and _LENGTH are in bytes.  _LENGTH symbols are \#defines instead of
79  * global variables because they are usually used when declaring byte
80  * arrays and some compilers require compile-time knowledge of array
81  * sizes when declared on the stack.
82  *
83  * \{
84  */
85 
86 
87 /*
88 	Most of the values described in this file are defined by the FLAC
89 	format specification.  There is nothing to tune here.
90 */
91 
92 /** The largest legal metadata type code. */
93 #define FLAC__MAX_METADATA_TYPE_CODE (126u)
94 
95 /** The minimum block size, in samples, permitted by the format. */
96 #define FLAC__MIN_BLOCK_SIZE (16u)
97 
98 /** The maximum block size, in samples, permitted by the format. */
99 #define FLAC__MAX_BLOCK_SIZE (65535u)
100 
101 /** The maximum block size, in samples, permitted by the FLAC subset for
102  *  sample rates up to 48kHz. */
103 #define FLAC__SUBSET_MAX_BLOCK_SIZE_48000HZ (4608u)
104 
105 /** The maximum number of channels permitted by the format. */
106 #define FLAC__MAX_CHANNELS (8u)
107 
108 /** The minimum sample resolution permitted by the format. */
109 #define FLAC__MIN_BITS_PER_SAMPLE (4u)
110 
111 /** The maximum sample resolution permitted by the format. */
112 #define FLAC__MAX_BITS_PER_SAMPLE (32u)
113 
114 /** The maximum sample resolution permitted by libFLAC.
115  *
116  * \warning
117  * FLAC__MAX_BITS_PER_SAMPLE is the limit of the FLAC format.  However,
118  * the reference encoder/decoder is currently limited to 24 bits because
119  * of prevalent 32-bit math, so make sure and use this value when
120  * appropriate.
121  */
122 #define FLAC__REFERENCE_CODEC_MAX_BITS_PER_SAMPLE (24u)
123 
124 /** The maximum sample rate permitted by the format.  The value is
125  *  ((2 ^ 16) - 1) * 10; see <A HREF="../format.html">FLAC format</A>
126  *  as to why.
127  */
128 #define FLAC__MAX_SAMPLE_RATE (655350u)
129 
130 /** The maximum LPC order permitted by the format. */
131 #define FLAC__MAX_LPC_ORDER (32u)
132 
133 /** The maximum LPC order permitted by the FLAC subset for sample rates
134  *  up to 48kHz. */
135 #define FLAC__SUBSET_MAX_LPC_ORDER_48000HZ (12u)
136 
137 /** The minimum quantized linear predictor coefficient precision
138  *  permitted by the format.
139  */
140 #define FLAC__MIN_QLP_COEFF_PRECISION (5u)
141 
142 /** The maximum quantized linear predictor coefficient precision
143  *  permitted by the format.
144  */
145 #define FLAC__MAX_QLP_COEFF_PRECISION (15u)
146 
147 /** The maximum order of the fixed predictors permitted by the format. */
148 #define FLAC__MAX_FIXED_ORDER (4u)
149 
150 /** The maximum Rice partition order permitted by the format. */
151 #define FLAC__MAX_RICE_PARTITION_ORDER (15u)
152 
153 /** The maximum Rice partition order permitted by the FLAC Subset. */
154 #define FLAC__SUBSET_MAX_RICE_PARTITION_ORDER (8u)
155 
156 /** The version string of the release, stamped onto the libraries and binaries.
157  *
158  * \note
159  * This does not correspond to the shared library version number, which
160  * is used to determine binary compatibility.
161  */
162 extern FLAC_API const char *FLAC__VERSION_STRING;
163 
164 /** The vendor string inserted by the encoder into the VORBIS_COMMENT block.
165  *  This is a NUL-terminated ASCII string; when inserted into the
166  *  VORBIS_COMMENT the trailing null is stripped.
167  */
168 extern FLAC_API const char *FLAC__VENDOR_STRING;
169 
170 /** The byte string representation of the beginning of a FLAC stream. */
171 extern FLAC_API const FLAC__byte FLAC__STREAM_SYNC_STRING[4]; /* = "fLaC" */
172 
173 /** The 32-bit integer big-endian representation of the beginning of
174  *  a FLAC stream.
175  */
176 extern FLAC_API const uint32_t FLAC__STREAM_SYNC; /* = 0x664C6143 */
177 
178 /** The length of the FLAC signature in bits. */
179 extern FLAC_API const uint32_t FLAC__STREAM_SYNC_LEN; /* = 32 bits */
180 
181 /** The length of the FLAC signature in bytes. */
182 #define FLAC__STREAM_SYNC_LENGTH (4u)
183 
184 
185 /*****************************************************************************
186  *
187  * Subframe structures
188  *
189  *****************************************************************************/
190 
191 /*****************************************************************************/
192 
193 /** An enumeration of the available entropy coding methods. */
194 typedef enum {
195 	FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE = 0,
196 	/**< Residual is coded by partitioning into contexts, each with it's own
197 	 * 4-bit Rice parameter. */
198 
199 	FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE2 = 1
200 	/**< Residual is coded by partitioning into contexts, each with it's own
201 	 * 5-bit Rice parameter. */
202 } FLAC__EntropyCodingMethodType;
203 
204 /** Maps a FLAC__EntropyCodingMethodType to a C string.
205  *
206  *  Using a FLAC__EntropyCodingMethodType as the index to this array will
207  *  give the string equivalent.  The contents should not be modified.
208  */
209 extern FLAC_API const char * const FLAC__EntropyCodingMethodTypeString[];
210 
211 
212 /** Contents of a Rice partitioned residual
213  */
214 typedef struct {
215 
216 	uint32_t *parameters;
217 	/**< The Rice parameters for each context. */
218 
219 	uint32_t *raw_bits;
220 	/**< Widths for escape-coded partitions.  Will be non-zero for escaped
221 	 * partitions and zero for unescaped partitions.
222 	 */
223 
224 	uint32_t capacity_by_order;
225 	/**< The capacity of the \a parameters and \a raw_bits arrays
226 	 * specified as an order, i.e. the number of array elements
227 	 * allocated is 2 ^ \a capacity_by_order.
228 	 */
229 } FLAC__EntropyCodingMethod_PartitionedRiceContents;
230 
231 /** Header for a Rice partitioned residual.  (c.f. <A HREF="../format.html#partitioned_rice">format specification</A>)
232  */
233 typedef struct {
234 
235 	uint32_t order;
236 	/**< The partition order, i.e. # of contexts = 2 ^ \a order. */
237 
238 	const FLAC__EntropyCodingMethod_PartitionedRiceContents *contents;
239 	/**< The context's Rice parameters and/or raw bits. */
240 
241 } FLAC__EntropyCodingMethod_PartitionedRice;
242 
243 extern FLAC_API const uint32_t FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_ORDER_LEN; /**< == 4 (bits) */
244 extern FLAC_API const uint32_t FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_PARAMETER_LEN; /**< == 4 (bits) */
245 extern FLAC_API const uint32_t FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE2_PARAMETER_LEN; /**< == 5 (bits) */
246 extern FLAC_API const uint32_t FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_RAW_LEN; /**< == 5 (bits) */
247 
248 extern FLAC_API const uint32_t FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_ESCAPE_PARAMETER;
249 /**< == (1<<FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_PARAMETER_LEN)-1 */
250 extern FLAC_API const uint32_t FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE2_ESCAPE_PARAMETER;
251 /**< == (1<<FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE2_PARAMETER_LEN)-1 */
252 
253 /** Header for the entropy coding method.  (c.f. <A HREF="../format.html#residual">format specification</A>)
254  */
255 typedef struct {
256 	FLAC__EntropyCodingMethodType type;
257 	union {
258 		FLAC__EntropyCodingMethod_PartitionedRice partitioned_rice;
259 	} data;
260 } FLAC__EntropyCodingMethod;
261 
262 extern FLAC_API const uint32_t FLAC__ENTROPY_CODING_METHOD_TYPE_LEN; /**< == 2 (bits) */
263 
264 /*****************************************************************************/
265 
266 /** An enumeration of the available subframe types. */
267 typedef enum {
268 	FLAC__SUBFRAME_TYPE_CONSTANT = 0, /**< constant signal */
269 	FLAC__SUBFRAME_TYPE_VERBATIM = 1, /**< uncompressed signal */
270 	FLAC__SUBFRAME_TYPE_FIXED = 2, /**< fixed polynomial prediction */
271 	FLAC__SUBFRAME_TYPE_LPC = 3 /**< linear prediction */
272 } FLAC__SubframeType;
273 
274 /** Maps a FLAC__SubframeType to a C string.
275  *
276  *  Using a FLAC__SubframeType as the index to this array will
277  *  give the string equivalent.  The contents should not be modified.
278  */
279 extern FLAC_API const char * const FLAC__SubframeTypeString[];
280 
281 
282 /** CONSTANT subframe.  (c.f. <A HREF="../format.html#subframe_constant">format specification</A>)
283  */
284 typedef struct {
285 	FLAC__int32 value; /**< The constant signal value. */
286 } FLAC__Subframe_Constant;
287 
288 
289 /** VERBATIM subframe.  (c.f. <A HREF="../format.html#subframe_verbatim">format specification</A>)
290  */
291 typedef struct {
292 	const FLAC__int32 *data; /**< A pointer to verbatim signal. */
293 } FLAC__Subframe_Verbatim;
294 
295 
296 /** FIXED subframe.  (c.f. <A HREF="../format.html#subframe_fixed">format specification</A>)
297  */
298 typedef struct {
299 	FLAC__EntropyCodingMethod entropy_coding_method;
300 	/**< The residual coding method. */
301 
302 	uint32_t order;
303 	/**< The polynomial order. */
304 
305 	FLAC__int32 warmup[FLAC__MAX_FIXED_ORDER];
306 	/**< Warmup samples to prime the predictor, length == order. */
307 
308 	const FLAC__int32 *residual;
309 	/**< The residual signal, length == (blocksize minus order) samples. */
310 } FLAC__Subframe_Fixed;
311 
312 
313 /** LPC subframe.  (c.f. <A HREF="../format.html#subframe_lpc">format specification</A>)
314  */
315 typedef struct {
316 	FLAC__EntropyCodingMethod entropy_coding_method;
317 	/**< The residual coding method. */
318 
319 	uint32_t order;
320 	/**< The FIR order. */
321 
322 	uint32_t qlp_coeff_precision;
323 	/**< Quantized FIR filter coefficient precision in bits. */
324 
325 	int quantization_level;
326 	/**< The qlp coeff shift needed. */
327 
328 	FLAC__int32 qlp_coeff[FLAC__MAX_LPC_ORDER];
329 	/**< FIR filter coefficients. */
330 
331 	FLAC__int32 warmup[FLAC__MAX_LPC_ORDER];
332 	/**< Warmup samples to prime the predictor, length == order. */
333 
334 	const FLAC__int32 *residual;
335 	/**< The residual signal, length == (blocksize minus order) samples. */
336 } FLAC__Subframe_LPC;
337 
338 extern FLAC_API const uint32_t FLAC__SUBFRAME_LPC_QLP_COEFF_PRECISION_LEN; /**< == 4 (bits) */
339 extern FLAC_API const uint32_t FLAC__SUBFRAME_LPC_QLP_SHIFT_LEN; /**< == 5 (bits) */
340 
341 
342 /** FLAC subframe structure.  (c.f. <A HREF="../format.html#subframe">format specification</A>)
343  */
344 typedef struct {
345 	FLAC__SubframeType type;
346 	union {
347 		FLAC__Subframe_Constant constant;
348 		FLAC__Subframe_Fixed fixed;
349 		FLAC__Subframe_LPC lpc;
350 		FLAC__Subframe_Verbatim verbatim;
351 	} data;
352 	uint32_t wasted_bits;
353 } FLAC__Subframe;
354 
355 /** == 1 (bit)
356  *
357  * This used to be a zero-padding bit (hence the name
358  * FLAC__SUBFRAME_ZERO_PAD_LEN) but is now a reserved bit.  It still has a
359  * mandatory value of \c 0 but in the future may take on the value \c 0 or \c 1
360  * to mean something else.
361  */
362 extern FLAC_API const uint32_t FLAC__SUBFRAME_ZERO_PAD_LEN;
363 extern FLAC_API const uint32_t FLAC__SUBFRAME_TYPE_LEN; /**< == 6 (bits) */
364 extern FLAC_API const uint32_t FLAC__SUBFRAME_WASTED_BITS_FLAG_LEN; /**< == 1 (bit) */
365 
366 extern FLAC_API const uint32_t FLAC__SUBFRAME_TYPE_CONSTANT_BYTE_ALIGNED_MASK; /**< = 0x00 */
367 extern FLAC_API const uint32_t FLAC__SUBFRAME_TYPE_VERBATIM_BYTE_ALIGNED_MASK; /**< = 0x02 */
368 extern FLAC_API const uint32_t FLAC__SUBFRAME_TYPE_FIXED_BYTE_ALIGNED_MASK; /**< = 0x10 */
369 extern FLAC_API const uint32_t FLAC__SUBFRAME_TYPE_LPC_BYTE_ALIGNED_MASK; /**< = 0x40 */
370 
371 /*****************************************************************************/
372 
373 
374 /*****************************************************************************
375  *
376  * Frame structures
377  *
378  *****************************************************************************/
379 
380 /** An enumeration of the available channel assignments. */
381 typedef enum {
382 	FLAC__CHANNEL_ASSIGNMENT_INDEPENDENT = 0, /**< independent channels */
383 	FLAC__CHANNEL_ASSIGNMENT_LEFT_SIDE = 1, /**< left+side stereo */
384 	FLAC__CHANNEL_ASSIGNMENT_RIGHT_SIDE = 2, /**< right+side stereo */
385 	FLAC__CHANNEL_ASSIGNMENT_MID_SIDE = 3 /**< mid+side stereo */
386 } FLAC__ChannelAssignment;
387 
388 /** Maps a FLAC__ChannelAssignment to a C string.
389  *
390  *  Using a FLAC__ChannelAssignment as the index to this array will
391  *  give the string equivalent.  The contents should not be modified.
392  */
393 extern FLAC_API const char * const FLAC__ChannelAssignmentString[];
394 
395 /** An enumeration of the possible frame numbering methods. */
396 typedef enum {
397 	FLAC__FRAME_NUMBER_TYPE_FRAME_NUMBER, /**< number contains the frame number */
398 	FLAC__FRAME_NUMBER_TYPE_SAMPLE_NUMBER /**< number contains the sample number of first sample in frame */
399 } FLAC__FrameNumberType;
400 
401 /** Maps a FLAC__FrameNumberType to a C string.
402  *
403  *  Using a FLAC__FrameNumberType as the index to this array will
404  *  give the string equivalent.  The contents should not be modified.
405  */
406 extern FLAC_API const char * const FLAC__FrameNumberTypeString[];
407 
408 
409 /** FLAC frame header structure.  (c.f. <A HREF="../format.html#frame_header">format specification</A>)
410  */
411 typedef struct {
412 	uint32_t blocksize;
413 	/**< The number of samples per subframe. */
414 
415 	uint32_t sample_rate;
416 	/**< The sample rate in Hz. */
417 
418 	uint32_t channels;
419 	/**< The number of channels (== number of subframes). */
420 
421 	FLAC__ChannelAssignment channel_assignment;
422 	/**< The channel assignment for the frame. */
423 
424 	uint32_t bits_per_sample;
425 	/**< The sample resolution. */
426 
427 	FLAC__FrameNumberType number_type;
428 	/**< The numbering scheme used for the frame.  As a convenience, the
429 	 * decoder will always convert a frame number to a sample number because
430 	 * the rules are complex. */
431 
432 	union {
433 		FLAC__uint32 frame_number;
434 		FLAC__uint64 sample_number;
435 	} number;
436 	/**< The frame number or sample number of first sample in frame;
437 	 * use the \a number_type value to determine which to use. */
438 
439 	FLAC__uint8 crc;
440 	/**< CRC-8 (polynomial = x^8 + x^2 + x^1 + x^0, initialized with 0)
441 	 * of the raw frame header bytes, meaning everything before the CRC byte
442 	 * including the sync code.
443 	 */
444 } FLAC__FrameHeader;
445 
446 extern FLAC_API const uint32_t FLAC__FRAME_HEADER_SYNC; /**< == 0x3ffe; the frame header sync code */
447 extern FLAC_API const uint32_t FLAC__FRAME_HEADER_SYNC_LEN; /**< == 14 (bits) */
448 extern FLAC_API const uint32_t FLAC__FRAME_HEADER_RESERVED_LEN; /**< == 1 (bits) */
449 extern FLAC_API const uint32_t FLAC__FRAME_HEADER_BLOCKING_STRATEGY_LEN; /**< == 1 (bits) */
450 extern FLAC_API const uint32_t FLAC__FRAME_HEADER_BLOCK_SIZE_LEN; /**< == 4 (bits) */
451 extern FLAC_API const uint32_t FLAC__FRAME_HEADER_SAMPLE_RATE_LEN; /**< == 4 (bits) */
452 extern FLAC_API const uint32_t FLAC__FRAME_HEADER_CHANNEL_ASSIGNMENT_LEN; /**< == 4 (bits) */
453 extern FLAC_API const uint32_t FLAC__FRAME_HEADER_BITS_PER_SAMPLE_LEN; /**< == 3 (bits) */
454 extern FLAC_API const uint32_t FLAC__FRAME_HEADER_ZERO_PAD_LEN; /**< == 1 (bit) */
455 extern FLAC_API const uint32_t FLAC__FRAME_HEADER_CRC_LEN; /**< == 8 (bits) */
456 
457 
458 /** FLAC frame footer structure.  (c.f. <A HREF="../format.html#frame_footer">format specification</A>)
459  */
460 typedef struct {
461 	FLAC__uint16 crc;
462 	/**< CRC-16 (polynomial = x^16 + x^15 + x^2 + x^0, initialized with
463 	 * 0) of the bytes before the crc, back to and including the frame header
464 	 * sync code.
465 	 */
466 } FLAC__FrameFooter;
467 
468 extern FLAC_API const uint32_t FLAC__FRAME_FOOTER_CRC_LEN; /**< == 16 (bits) */
469 
470 
471 /** FLAC frame structure.  (c.f. <A HREF="../format.html#frame">format specification</A>)
472  */
473 typedef struct {
474 	FLAC__FrameHeader header;
475 	FLAC__Subframe subframes[FLAC__MAX_CHANNELS];
476 	FLAC__FrameFooter footer;
477 } FLAC__Frame;
478 
479 /*****************************************************************************/
480 
481 
482 /*****************************************************************************
483  *
484  * Meta-data structures
485  *
486  *****************************************************************************/
487 
488 /** An enumeration of the available metadata block types. */
489 typedef enum {
490 
491 	FLAC__METADATA_TYPE_STREAMINFO = 0,
492 	/**< <A HREF="../format.html#metadata_block_streaminfo">STREAMINFO</A> block */
493 
494 	FLAC__METADATA_TYPE_PADDING = 1,
495 	/**< <A HREF="../format.html#metadata_block_padding">PADDING</A> block */
496 
497 	FLAC__METADATA_TYPE_APPLICATION = 2,
498 	/**< <A HREF="../format.html#metadata_block_application">APPLICATION</A> block */
499 
500 	FLAC__METADATA_TYPE_SEEKTABLE = 3,
501 	/**< <A HREF="../format.html#metadata_block_seektable">SEEKTABLE</A> block */
502 
503 	FLAC__METADATA_TYPE_VORBIS_COMMENT = 4,
504 	/**< <A HREF="../format.html#metadata_block_vorbis_comment">VORBISCOMMENT</A> block (a.k.a. FLAC tags) */
505 
506 	FLAC__METADATA_TYPE_CUESHEET = 5,
507 	/**< <A HREF="../format.html#metadata_block_cuesheet">CUESHEET</A> block */
508 
509 	FLAC__METADATA_TYPE_PICTURE = 6,
510 	/**< <A HREF="../format.html#metadata_block_picture">PICTURE</A> block */
511 
512 	FLAC__METADATA_TYPE_UNDEFINED = 7,
513 	/**< marker to denote beginning of undefined type range; this number will increase as new metadata types are added */
514 
515 	FLAC__MAX_METADATA_TYPE = FLAC__MAX_METADATA_TYPE_CODE,
516 	/**< No type will ever be greater than this. There is not enough room in the protocol block. */
517 } FLAC__MetadataType;
518 
519 /** Maps a FLAC__MetadataType to a C string.
520  *
521  *  Using a FLAC__MetadataType as the index to this array will
522  *  give the string equivalent.  The contents should not be modified.
523  */
524 extern FLAC_API const char * const FLAC__MetadataTypeString[];
525 
526 
527 /** FLAC STREAMINFO structure.  (c.f. <A HREF="../format.html#metadata_block_streaminfo">format specification</A>)
528  */
529 typedef struct {
530 	uint32_t min_blocksize, max_blocksize;
531 	uint32_t min_framesize, max_framesize;
532 	uint32_t sample_rate;
533 	uint32_t channels;
534 	uint32_t bits_per_sample;
535 	FLAC__uint64 total_samples;
536 	FLAC__byte md5sum[16];
537 } FLAC__StreamMetadata_StreamInfo;
538 
539 extern FLAC_API const uint32_t FLAC__STREAM_METADATA_STREAMINFO_MIN_BLOCK_SIZE_LEN; /**< == 16 (bits) */
540 extern FLAC_API const uint32_t FLAC__STREAM_METADATA_STREAMINFO_MAX_BLOCK_SIZE_LEN; /**< == 16 (bits) */
541 extern FLAC_API const uint32_t FLAC__STREAM_METADATA_STREAMINFO_MIN_FRAME_SIZE_LEN; /**< == 24 (bits) */
542 extern FLAC_API const uint32_t FLAC__STREAM_METADATA_STREAMINFO_MAX_FRAME_SIZE_LEN; /**< == 24 (bits) */
543 extern FLAC_API const uint32_t FLAC__STREAM_METADATA_STREAMINFO_SAMPLE_RATE_LEN; /**< == 20 (bits) */
544 extern FLAC_API const uint32_t FLAC__STREAM_METADATA_STREAMINFO_CHANNELS_LEN; /**< == 3 (bits) */
545 extern FLAC_API const uint32_t FLAC__STREAM_METADATA_STREAMINFO_BITS_PER_SAMPLE_LEN; /**< == 5 (bits) */
546 extern FLAC_API const uint32_t FLAC__STREAM_METADATA_STREAMINFO_TOTAL_SAMPLES_LEN; /**< == 36 (bits) */
547 extern FLAC_API const uint32_t FLAC__STREAM_METADATA_STREAMINFO_MD5SUM_LEN; /**< == 128 (bits) */
548 
549 /** The total stream length of the STREAMINFO block in bytes. */
550 #define FLAC__STREAM_METADATA_STREAMINFO_LENGTH (34u)
551 
552 /** FLAC PADDING structure.  (c.f. <A HREF="../format.html#metadata_block_padding">format specification</A>)
553  */
554 typedef struct {
555 	int dummy;
556 	/**< Conceptually this is an empty struct since we don't store the
557 	 * padding bytes.  Empty structs are not allowed by some C compilers,
558 	 * hence the dummy.
559 	 */
560 } FLAC__StreamMetadata_Padding;
561 
562 
563 /** FLAC APPLICATION structure.  (c.f. <A HREF="../format.html#metadata_block_application">format specification</A>)
564  */
565 typedef struct {
566 	FLAC__byte id[4];
567 	FLAC__byte *data;
568 } FLAC__StreamMetadata_Application;
569 
570 extern FLAC_API const uint32_t FLAC__STREAM_METADATA_APPLICATION_ID_LEN; /**< == 32 (bits) */
571 
572 /** SeekPoint structure used in SEEKTABLE blocks.  (c.f. <A HREF="../format.html#seekpoint">format specification</A>)
573  */
574 typedef struct {
575 	FLAC__uint64 sample_number;
576 	/**<  The sample number of the target frame. */
577 
578 	FLAC__uint64 stream_offset;
579 	/**< The offset, in bytes, of the target frame with respect to
580 	 * beginning of the first frame. */
581 
582 	uint32_t frame_samples;
583 	/**< The number of samples in the target frame. */
584 } FLAC__StreamMetadata_SeekPoint;
585 
586 extern FLAC_API const uint32_t FLAC__STREAM_METADATA_SEEKPOINT_SAMPLE_NUMBER_LEN; /**< == 64 (bits) */
587 extern FLAC_API const uint32_t FLAC__STREAM_METADATA_SEEKPOINT_STREAM_OFFSET_LEN; /**< == 64 (bits) */
588 extern FLAC_API const uint32_t FLAC__STREAM_METADATA_SEEKPOINT_FRAME_SAMPLES_LEN; /**< == 16 (bits) */
589 
590 /** The total stream length of a seek point in bytes. */
591 #define FLAC__STREAM_METADATA_SEEKPOINT_LENGTH (18u)
592 
593 /** The value used in the \a sample_number field of
594  *  FLAC__StreamMetadataSeekPoint used to indicate a placeholder
595  *  point (== 0xffffffffffffffff).
596  */
597 extern FLAC_API const FLAC__uint64 FLAC__STREAM_METADATA_SEEKPOINT_PLACEHOLDER;
598 
599 
600 /** FLAC SEEKTABLE structure.  (c.f. <A HREF="../format.html#metadata_block_seektable">format specification</A>)
601  *
602  * \note From the format specification:
603  * - The seek points must be sorted by ascending sample number.
604  * - Each seek point's sample number must be the first sample of the
605  *   target frame.
606  * - Each seek point's sample number must be unique within the table.
607  * - Existence of a SEEKTABLE block implies a correct setting of
608  *   total_samples in the stream_info block.
609  * - Behavior is undefined when more than one SEEKTABLE block is
610  *   present in a stream.
611  */
612 typedef struct {
613 	uint32_t num_points;
614 	FLAC__StreamMetadata_SeekPoint *points;
615 } FLAC__StreamMetadata_SeekTable;
616 
617 
618 /** Vorbis comment entry structure used in VORBIS_COMMENT blocks.  (c.f. <A HREF="../format.html#metadata_block_vorbis_comment">format specification</A>)
619  *
620  *  For convenience, the APIs maintain a trailing NUL character at the end of
621  *  \a entry which is not counted toward \a length, i.e.
622  *  \code strlen(entry) == length \endcode
623  */
624 typedef struct {
625 	FLAC__uint32 length;
626 	FLAC__byte *entry;
627 } FLAC__StreamMetadata_VorbisComment_Entry;
628 
629 extern FLAC_API const uint32_t FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN; /**< == 32 (bits) */
630 
631 
632 /** FLAC VORBIS_COMMENT structure.  (c.f. <A HREF="../format.html#metadata_block_vorbis_comment">format specification</A>)
633  */
634 typedef struct {
635 	FLAC__StreamMetadata_VorbisComment_Entry vendor_string;
636 	FLAC__uint32 num_comments;
637 	FLAC__StreamMetadata_VorbisComment_Entry *comments;
638 } FLAC__StreamMetadata_VorbisComment;
639 
640 extern FLAC_API const uint32_t FLAC__STREAM_METADATA_VORBIS_COMMENT_NUM_COMMENTS_LEN; /**< == 32 (bits) */
641 
642 
643 /** FLAC CUESHEET track index structure.  (See the
644  * <A HREF="../format.html#cuesheet_track_index">format specification</A> for
645  * the full description of each field.)
646  */
647 typedef struct {
648 	FLAC__uint64 offset;
649 	/**< Offset in samples, relative to the track offset, of the index
650 	 * point.
651 	 */
652 
653 	FLAC__byte number;
654 	/**< The index point number. */
655 } FLAC__StreamMetadata_CueSheet_Index;
656 
657 extern FLAC_API const uint32_t FLAC__STREAM_METADATA_CUESHEET_INDEX_OFFSET_LEN; /**< == 64 (bits) */
658 extern FLAC_API const uint32_t FLAC__STREAM_METADATA_CUESHEET_INDEX_NUMBER_LEN; /**< == 8 (bits) */
659 extern FLAC_API const uint32_t FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN; /**< == 3*8 (bits) */
660 
661 
662 /** FLAC CUESHEET track structure.  (See the
663  * <A HREF="../format.html#cuesheet_track">format specification</A> for
664  * the full description of each field.)
665  */
666 typedef struct {
667 	FLAC__uint64 offset;
668 	/**< Track offset in samples, relative to the beginning of the FLAC audio stream. */
669 
670 	FLAC__byte number;
671 	/**< The track number. */
672 
673 	char isrc[13];
674 	/**< Track ISRC.  This is a 12-digit alphanumeric code plus a trailing \c NUL byte */
675 
676 	uint32_t type:1;
677 	/**< The track type: 0 for audio, 1 for non-audio. */
678 
679 	uint32_t pre_emphasis:1;
680 	/**< The pre-emphasis flag: 0 for no pre-emphasis, 1 for pre-emphasis. */
681 
682 	FLAC__byte num_indices;
683 	/**< The number of track index points. */
684 
685 	FLAC__StreamMetadata_CueSheet_Index *indices;
686 	/**< NULL if num_indices == 0, else pointer to array of index points. */
687 
688 } FLAC__StreamMetadata_CueSheet_Track;
689 
690 extern FLAC_API const uint32_t FLAC__STREAM_METADATA_CUESHEET_TRACK_OFFSET_LEN; /**< == 64 (bits) */
691 extern FLAC_API const uint32_t FLAC__STREAM_METADATA_CUESHEET_TRACK_NUMBER_LEN; /**< == 8 (bits) */
692 extern FLAC_API const uint32_t FLAC__STREAM_METADATA_CUESHEET_TRACK_ISRC_LEN; /**< == 12*8 (bits) */
693 extern FLAC_API const uint32_t FLAC__STREAM_METADATA_CUESHEET_TRACK_TYPE_LEN; /**< == 1 (bit) */
694 extern FLAC_API const uint32_t FLAC__STREAM_METADATA_CUESHEET_TRACK_PRE_EMPHASIS_LEN; /**< == 1 (bit) */
695 extern FLAC_API const uint32_t FLAC__STREAM_METADATA_CUESHEET_TRACK_RESERVED_LEN; /**< == 6+13*8 (bits) */
696 extern FLAC_API const uint32_t FLAC__STREAM_METADATA_CUESHEET_TRACK_NUM_INDICES_LEN; /**< == 8 (bits) */
697 
698 
699 /** FLAC CUESHEET structure.  (See the
700  * <A HREF="../format.html#metadata_block_cuesheet">format specification</A>
701  * for the full description of each field.)
702  */
703 typedef struct {
704 	char media_catalog_number[129];
705 	/**< Media catalog number, in ASCII printable characters 0x20-0x7e.  In
706 	 * general, the media catalog number may be 0 to 128 bytes long; any
707 	 * unused characters should be right-padded with NUL characters.
708 	 */
709 
710 	FLAC__uint64 lead_in;
711 	/**< The number of lead-in samples. */
712 
713 	FLAC__bool is_cd;
714 	/**< \c true if CUESHEET corresponds to a Compact Disc, else \c false. */
715 
716 	uint32_t num_tracks;
717 	/**< The number of tracks. */
718 
719 	FLAC__StreamMetadata_CueSheet_Track *tracks;
720 	/**< NULL if num_tracks == 0, else pointer to array of tracks. */
721 
722 } FLAC__StreamMetadata_CueSheet;
723 
724 extern FLAC_API const uint32_t FLAC__STREAM_METADATA_CUESHEET_MEDIA_CATALOG_NUMBER_LEN; /**< == 128*8 (bits) */
725 extern FLAC_API const uint32_t FLAC__STREAM_METADATA_CUESHEET_LEAD_IN_LEN; /**< == 64 (bits) */
726 extern FLAC_API const uint32_t FLAC__STREAM_METADATA_CUESHEET_IS_CD_LEN; /**< == 1 (bit) */
727 extern FLAC_API const uint32_t FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN; /**< == 7+258*8 (bits) */
728 extern FLAC_API const uint32_t FLAC__STREAM_METADATA_CUESHEET_NUM_TRACKS_LEN; /**< == 8 (bits) */
729 
730 
731 /** An enumeration of the PICTURE types (see FLAC__StreamMetadataPicture and id3 v2.4 APIC tag). */
732 typedef enum {
733 	FLAC__STREAM_METADATA_PICTURE_TYPE_OTHER = 0, /**< Other */
734 	FLAC__STREAM_METADATA_PICTURE_TYPE_FILE_ICON_STANDARD = 1, /**< 32x32 pixels 'file icon' (PNG only) */
735 	FLAC__STREAM_METADATA_PICTURE_TYPE_FILE_ICON = 2, /**< Other file icon */
736 	FLAC__STREAM_METADATA_PICTURE_TYPE_FRONT_COVER = 3, /**< Cover (front) */
737 	FLAC__STREAM_METADATA_PICTURE_TYPE_BACK_COVER = 4, /**< Cover (back) */
738 	FLAC__STREAM_METADATA_PICTURE_TYPE_LEAFLET_PAGE = 5, /**< Leaflet page */
739 	FLAC__STREAM_METADATA_PICTURE_TYPE_MEDIA = 6, /**< Media (e.g. label side of CD) */
740 	FLAC__STREAM_METADATA_PICTURE_TYPE_LEAD_ARTIST = 7, /**< Lead artist/lead performer/soloist */
741 	FLAC__STREAM_METADATA_PICTURE_TYPE_ARTIST = 8, /**< Artist/performer */
742 	FLAC__STREAM_METADATA_PICTURE_TYPE_CONDUCTOR = 9, /**< Conductor */
743 	FLAC__STREAM_METADATA_PICTURE_TYPE_BAND = 10, /**< Band/Orchestra */
744 	FLAC__STREAM_METADATA_PICTURE_TYPE_COMPOSER = 11, /**< Composer */
745 	FLAC__STREAM_METADATA_PICTURE_TYPE_LYRICIST = 12, /**< Lyricist/text writer */
746 	FLAC__STREAM_METADATA_PICTURE_TYPE_RECORDING_LOCATION = 13, /**< Recording Location */
747 	FLAC__STREAM_METADATA_PICTURE_TYPE_DURING_RECORDING = 14, /**< During recording */
748 	FLAC__STREAM_METADATA_PICTURE_TYPE_DURING_PERFORMANCE = 15, /**< During performance */
749 	FLAC__STREAM_METADATA_PICTURE_TYPE_VIDEO_SCREEN_CAPTURE = 16, /**< Movie/video screen capture */
750 	FLAC__STREAM_METADATA_PICTURE_TYPE_FISH = 17, /**< A bright coloured fish */
751 	FLAC__STREAM_METADATA_PICTURE_TYPE_ILLUSTRATION = 18, /**< Illustration */
752 	FLAC__STREAM_METADATA_PICTURE_TYPE_BAND_LOGOTYPE = 19, /**< Band/artist logotype */
753 	FLAC__STREAM_METADATA_PICTURE_TYPE_PUBLISHER_LOGOTYPE = 20, /**< Publisher/Studio logotype */
754 	FLAC__STREAM_METADATA_PICTURE_TYPE_UNDEFINED
755 } FLAC__StreamMetadata_Picture_Type;
756 
757 /** Maps a FLAC__StreamMetadata_Picture_Type to a C string.
758  *
759  *  Using a FLAC__StreamMetadata_Picture_Type as the index to this array
760  *  will give the string equivalent.  The contents should not be
761  *  modified.
762  */
763 extern FLAC_API const char * const FLAC__StreamMetadata_Picture_TypeString[];
764 
765 /** FLAC PICTURE structure.  (See the
766  * <A HREF="../format.html#metadata_block_picture">format specification</A>
767  * for the full description of each field.)
768  */
769 typedef struct {
770 	FLAC__StreamMetadata_Picture_Type type;
771 	/**< The kind of picture stored. */
772 
773 	char *mime_type;
774 	/**< Picture data's MIME type, in ASCII printable characters
775 	 * 0x20-0x7e, NUL terminated.  For best compatibility with players,
776 	 * use picture data of MIME type \c image/jpeg or \c image/png.  A
777 	 * MIME type of '-->' is also allowed, in which case the picture
778 	 * data should be a complete URL.  In file storage, the MIME type is
779 	 * stored as a 32-bit length followed by the ASCII string with no NUL
780 	 * terminator, but is converted to a plain C string in this structure
781 	 * for convenience.
782 	 */
783 
784 	FLAC__byte *description;
785 	/**< Picture's description in UTF-8, NUL terminated.  In file storage,
786 	 * the description is stored as a 32-bit length followed by the UTF-8
787 	 * string with no NUL terminator, but is converted to a plain C string
788 	 * in this structure for convenience.
789 	 */
790 
791 	FLAC__uint32 width;
792 	/**< Picture's width in pixels. */
793 
794 	FLAC__uint32 height;
795 	/**< Picture's height in pixels. */
796 
797 	FLAC__uint32 depth;
798 	/**< Picture's color depth in bits-per-pixel. */
799 
800 	FLAC__uint32 colors;
801 	/**< For indexed palettes (like GIF), picture's number of colors (the
802 	 * number of palette entries), or \c 0 for non-indexed (i.e. 2^depth).
803 	 */
804 
805 	FLAC__uint32 data_length;
806 	/**< Length of binary picture data in bytes. */
807 
808 	FLAC__byte *data;
809 	/**< Binary picture data. */
810 
811 } FLAC__StreamMetadata_Picture;
812 
813 extern FLAC_API const uint32_t FLAC__STREAM_METADATA_PICTURE_TYPE_LEN; /**< == 32 (bits) */
814 extern FLAC_API const uint32_t FLAC__STREAM_METADATA_PICTURE_MIME_TYPE_LENGTH_LEN; /**< == 32 (bits) */
815 extern FLAC_API const uint32_t FLAC__STREAM_METADATA_PICTURE_DESCRIPTION_LENGTH_LEN; /**< == 32 (bits) */
816 extern FLAC_API const uint32_t FLAC__STREAM_METADATA_PICTURE_WIDTH_LEN; /**< == 32 (bits) */
817 extern FLAC_API const uint32_t FLAC__STREAM_METADATA_PICTURE_HEIGHT_LEN; /**< == 32 (bits) */
818 extern FLAC_API const uint32_t FLAC__STREAM_METADATA_PICTURE_DEPTH_LEN; /**< == 32 (bits) */
819 extern FLAC_API const uint32_t FLAC__STREAM_METADATA_PICTURE_COLORS_LEN; /**< == 32 (bits) */
820 extern FLAC_API const uint32_t FLAC__STREAM_METADATA_PICTURE_DATA_LENGTH_LEN; /**< == 32 (bits) */
821 
822 
823 /** Structure that is used when a metadata block of unknown type is loaded.
824  *  The contents are opaque.  The structure is used only internally to
825  *  correctly handle unknown metadata.
826  */
827 typedef struct {
828 	FLAC__byte *data;
829 } FLAC__StreamMetadata_Unknown;
830 
831 
832 /** FLAC metadata block structure.  (c.f. <A HREF="../format.html#metadata_block">format specification</A>)
833  */
834 typedef struct {
835 	FLAC__MetadataType type;
836 	/**< The type of the metadata block; used determine which member of the
837 	 * \a data union to dereference.  If type >= FLAC__METADATA_TYPE_UNDEFINED
838 	 * then \a data.unknown must be used. */
839 
840 	FLAC__bool is_last;
841 	/**< \c true if this metadata block is the last, else \a false */
842 
843 	uint32_t length;
844 	/**< Length, in bytes, of the block data as it appears in the stream. */
845 
846 	union {
847 		FLAC__StreamMetadata_StreamInfo stream_info;
848 		FLAC__StreamMetadata_Padding padding;
849 		FLAC__StreamMetadata_Application application;
850 		FLAC__StreamMetadata_SeekTable seek_table;
851 		FLAC__StreamMetadata_VorbisComment vorbis_comment;
852 		FLAC__StreamMetadata_CueSheet cue_sheet;
853 		FLAC__StreamMetadata_Picture picture;
854 		FLAC__StreamMetadata_Unknown unknown;
855 	} data;
856 	/**< Polymorphic block data; use the \a type value to determine which
857 	 * to use. */
858 } FLAC__StreamMetadata;
859 
860 extern FLAC_API const uint32_t FLAC__STREAM_METADATA_IS_LAST_LEN; /**< == 1 (bit) */
861 extern FLAC_API const uint32_t FLAC__STREAM_METADATA_TYPE_LEN; /**< == 7 (bits) */
862 extern FLAC_API const uint32_t FLAC__STREAM_METADATA_LENGTH_LEN; /**< == 24 (bits) */
863 
864 /** The total stream length of a metadata block header in bytes. */
865 #define FLAC__STREAM_METADATA_HEADER_LENGTH (4u)
866 
867 /*****************************************************************************/
868 
869 
870 /*****************************************************************************
871  *
872  * Utility functions
873  *
874  *****************************************************************************/
875 
876 /** Tests that a sample rate is valid for FLAC.
877  *
878  * \param sample_rate  The sample rate to test for compliance.
879  * \retval FLAC__bool
880  *    \c true if the given sample rate conforms to the specification, else
881  *    \c false.
882  */
883 FLAC_API FLAC__bool FLAC__format_sample_rate_is_valid(uint32_t sample_rate);
884 
885 /** Tests that a blocksize at the given sample rate is valid for the FLAC
886  *  subset.
887  *
888  * \param blocksize    The blocksize to test for compliance.
889  * \param sample_rate  The sample rate is needed, since the valid subset
890  *                     blocksize depends on the sample rate.
891  * \retval FLAC__bool
892  *    \c true if the given blocksize conforms to the specification for the
893  *    subset at the given sample rate, else \c false.
894  */
895 FLAC_API FLAC__bool FLAC__format_blocksize_is_subset(uint32_t blocksize, uint32_t sample_rate);
896 
897 /** Tests that a sample rate is valid for the FLAC subset.  The subset rules
898  *  for valid sample rates are slightly more complex since the rate has to
899  *  be expressible completely in the frame header.
900  *
901  * \param sample_rate  The sample rate to test for compliance.
902  * \retval FLAC__bool
903  *    \c true if the given sample rate conforms to the specification for the
904  *    subset, else \c false.
905  */
906 FLAC_API FLAC__bool FLAC__format_sample_rate_is_subset(uint32_t sample_rate);
907 
908 /** Check a Vorbis comment entry name to see if it conforms to the Vorbis
909  *  comment specification.
910  *
911  *  Vorbis comment names must be composed only of characters from
912  *  [0x20-0x3C,0x3E-0x7D].
913  *
914  * \param name       A NUL-terminated string to be checked.
915  * \assert
916  *    \code name != NULL \endcode
917  * \retval FLAC__bool
918  *    \c false if entry name is illegal, else \c true.
919  */
920 FLAC_API FLAC__bool FLAC__format_vorbiscomment_entry_name_is_legal(const char *name);
921 
922 /** Check a Vorbis comment entry value to see if it conforms to the Vorbis
923  *  comment specification.
924  *
925  *  Vorbis comment values must be valid UTF-8 sequences.
926  *
927  * \param value      A string to be checked.
928  * \param length     A the length of \a value in bytes.  May be
929  *                   \c (uint32_t)(-1) to indicate that \a value is a plain
930  *                   UTF-8 NUL-terminated string.
931  * \assert
932  *    \code value != NULL \endcode
933  * \retval FLAC__bool
934  *    \c false if entry name is illegal, else \c true.
935  */
936 FLAC_API FLAC__bool FLAC__format_vorbiscomment_entry_value_is_legal(const FLAC__byte *value, uint32_t length);
937 
938 /** Check a Vorbis comment entry to see if it conforms to the Vorbis
939  *  comment specification.
940  *
941  *  Vorbis comment entries must be of the form 'name=value', and 'name' and
942  *  'value' must be legal according to
943  *  FLAC__format_vorbiscomment_entry_name_is_legal() and
944  *  FLAC__format_vorbiscomment_entry_value_is_legal() respectively.
945  *
946  * \param entry      An entry to be checked.
947  * \param length     The length of \a entry in bytes.
948  * \assert
949  *    \code value != NULL \endcode
950  * \retval FLAC__bool
951  *    \c false if entry name is illegal, else \c true.
952  */
953 FLAC_API FLAC__bool FLAC__format_vorbiscomment_entry_is_legal(const FLAC__byte *entry, uint32_t length);
954 
955 /** Check a seek table to see if it conforms to the FLAC specification.
956  *  See the format specification for limits on the contents of the
957  *  seek table.
958  *
959  * \param seek_table  A pointer to a seek table to be checked.
960  * \assert
961  *    \code seek_table != NULL \endcode
962  * \retval FLAC__bool
963  *    \c false if seek table is illegal, else \c true.
964  */
965 FLAC_API FLAC__bool FLAC__format_seektable_is_legal(const FLAC__StreamMetadata_SeekTable *seek_table);
966 
967 /** Sort a seek table's seek points according to the format specification.
968  *  This includes a "unique-ification" step to remove duplicates, i.e.
969  *  seek points with identical \a sample_number values.  Duplicate seek
970  *  points are converted into placeholder points and sorted to the end of
971  *  the table.
972  *
973  * \param seek_table  A pointer to a seek table to be sorted.
974  * \assert
975  *    \code seek_table != NULL \endcode
976  * \retval uint32_t
977  *    The number of duplicate seek points converted into placeholders.
978  */
979 FLAC_API uint32_t FLAC__format_seektable_sort(FLAC__StreamMetadata_SeekTable *seek_table);
980 
981 /** Check a cue sheet to see if it conforms to the FLAC specification.
982  *  See the format specification for limits on the contents of the
983  *  cue sheet.
984  *
985  * \param cue_sheet  A pointer to an existing cue sheet to be checked.
986  * \param check_cd_da_subset  If \c true, check CUESHEET against more
987  *                   stringent requirements for a CD-DA (audio) disc.
988  * \param violation  Address of a pointer to a string.  If there is a
989  *                   violation, a pointer to a string explanation of the
990  *                   violation will be returned here. \a violation may be
991  *                   \c NULL if you don't need the returned string.  Do not
992  *                   free the returned string; it will always point to static
993  *                   data.
994  * \assert
995  *    \code cue_sheet != NULL \endcode
996  * \retval FLAC__bool
997  *    \c false if cue sheet is illegal, else \c true.
998  */
999 FLAC_API FLAC__bool FLAC__format_cuesheet_is_legal(const FLAC__StreamMetadata_CueSheet *cue_sheet, FLAC__bool check_cd_da_subset, const char **violation);
1000 
1001 /** Check picture data to see if it conforms to the FLAC specification.
1002  *  See the format specification for limits on the contents of the
1003  *  PICTURE block.
1004  *
1005  * \param picture    A pointer to existing picture data to be checked.
1006  * \param violation  Address of a pointer to a string.  If there is a
1007  *                   violation, a pointer to a string explanation of the
1008  *                   violation will be returned here. \a violation may be
1009  *                   \c NULL if you don't need the returned string.  Do not
1010  *                   free the returned string; it will always point to static
1011  *                   data.
1012  * \assert
1013  *    \code picture != NULL \endcode
1014  * \retval FLAC__bool
1015  *    \c false if picture data is illegal, else \c true.
1016  */
1017 FLAC_API FLAC__bool FLAC__format_picture_is_legal(const FLAC__StreamMetadata_Picture *picture, const char **violation);
1018 
1019 /* \} */
1020 
1021 #ifdef __cplusplus
1022 }
1023 #endif
1024 
1025 #endif
1026