Home | History | Annotate | Download | only in FLAC
      1 /* libFLAC - Free Lossless Audio Codec library
      2  * Copyright (C) 2000-2009  Josh Coalson
      3  * Copyright (C) 2011-2014  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 unsigned FLAC__STREAM_SYNC; /* = 0x664C6143 */
    177 
    178 /** The length of the FLAC signature in bits. */
    179 extern FLAC_API const unsigned 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 	unsigned *parameters;
    217 	/**< The Rice parameters for each context. */
    218 
    219 	unsigned *raw_bits;
    220 	/**< Widths for escape-coded partitions.  Will be non-zero for escaped
    221 	 * partitions and zero for unescaped partitions.
    222 	 */
    223 
    224 	unsigned 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 	unsigned 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 unsigned FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_ORDER_LEN; /**< == 4 (bits) */
    244 extern FLAC_API const unsigned FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_PARAMETER_LEN; /**< == 4 (bits) */
    245 extern FLAC_API const unsigned FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE2_PARAMETER_LEN; /**< == 5 (bits) */
    246 extern FLAC_API const unsigned FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_RAW_LEN; /**< == 5 (bits) */
    247 
    248 extern FLAC_API const unsigned FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_ESCAPE_PARAMETER;
    249 /**< == (1<<FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_PARAMETER_LEN)-1 */
    250 extern FLAC_API const unsigned 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 unsigned 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 	unsigned 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 	unsigned order;
    320 	/**< The FIR order. */
    321 
    322 	unsigned 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 unsigned FLAC__SUBFRAME_LPC_QLP_COEFF_PRECISION_LEN; /**< == 4 (bits) */
    339 extern FLAC_API const unsigned 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 	unsigned 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 unsigned FLAC__SUBFRAME_ZERO_PAD_LEN;
    363 extern FLAC_API const unsigned FLAC__SUBFRAME_TYPE_LEN; /**< == 6 (bits) */
    364 extern FLAC_API const unsigned FLAC__SUBFRAME_WASTED_BITS_FLAG_LEN; /**< == 1 (bit) */
    365 
    366 extern FLAC_API const unsigned FLAC__SUBFRAME_TYPE_CONSTANT_BYTE_ALIGNED_MASK; /**< = 0x00 */
    367 extern FLAC_API const unsigned FLAC__SUBFRAME_TYPE_VERBATIM_BYTE_ALIGNED_MASK; /**< = 0x02 */
    368 extern FLAC_API const unsigned FLAC__SUBFRAME_TYPE_FIXED_BYTE_ALIGNED_MASK; /**< = 0x10 */
    369 extern FLAC_API const unsigned 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 	unsigned blocksize;
    413 	/**< The number of samples per subframe. */
    414 
    415 	unsigned sample_rate;
    416 	/**< The sample rate in Hz. */
    417 
    418 	unsigned channels;
    419 	/**< The number of channels (== number of subframes). */
    420 
    421 	FLAC__ChannelAssignment channel_assignment;
    422 	/**< The channel assignment for the frame. */
    423 
    424 	unsigned 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 unsigned FLAC__FRAME_HEADER_SYNC; /**< == 0x3ffe; the frame header sync code */
    447 extern FLAC_API const unsigned FLAC__FRAME_HEADER_SYNC_LEN; /**< == 14 (bits) */
    448 extern FLAC_API const unsigned FLAC__FRAME_HEADER_RESERVED_LEN; /**< == 1 (bits) */
    449 extern FLAC_API const unsigned FLAC__FRAME_HEADER_BLOCKING_STRATEGY_LEN; /**< == 1 (bits) */
    450 extern FLAC_API const unsigned FLAC__FRAME_HEADER_BLOCK_SIZE_LEN; /**< == 4 (bits) */
    451 extern FLAC_API const unsigned FLAC__FRAME_HEADER_SAMPLE_RATE_LEN; /**< == 4 (bits) */
    452 extern FLAC_API const unsigned FLAC__FRAME_HEADER_CHANNEL_ASSIGNMENT_LEN; /**< == 4 (bits) */
    453 extern FLAC_API const unsigned FLAC__FRAME_HEADER_BITS_PER_SAMPLE_LEN; /**< == 3 (bits) */
    454 extern FLAC_API const unsigned FLAC__FRAME_HEADER_ZERO_PAD_LEN; /**< == 1 (bit) */
    455 extern FLAC_API const unsigned 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 unsigned 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 	unsigned min_blocksize, max_blocksize;
    531 	unsigned min_framesize, max_framesize;
    532 	unsigned sample_rate;
    533 	unsigned channels;
    534 	unsigned bits_per_sample;
    535 	FLAC__uint64 total_samples;
    536 	FLAC__byte md5sum[16];
    537 } FLAC__StreamMetadata_StreamInfo;
    538 
    539 extern FLAC_API const unsigned FLAC__STREAM_METADATA_STREAMINFO_MIN_BLOCK_SIZE_LEN; /**< == 16 (bits) */
    540 extern FLAC_API const unsigned FLAC__STREAM_METADATA_STREAMINFO_MAX_BLOCK_SIZE_LEN; /**< == 16 (bits) */
    541 extern FLAC_API const unsigned FLAC__STREAM_METADATA_STREAMINFO_MIN_FRAME_SIZE_LEN; /**< == 24 (bits) */
    542 extern FLAC_API const unsigned FLAC__STREAM_METADATA_STREAMINFO_MAX_FRAME_SIZE_LEN; /**< == 24 (bits) */
    543 extern FLAC_API const unsigned FLAC__STREAM_METADATA_STREAMINFO_SAMPLE_RATE_LEN; /**< == 20 (bits) */
    544 extern FLAC_API const unsigned FLAC__STREAM_METADATA_STREAMINFO_CHANNELS_LEN; /**< == 3 (bits) */
    545 extern FLAC_API const unsigned FLAC__STREAM_METADATA_STREAMINFO_BITS_PER_SAMPLE_LEN; /**< == 5 (bits) */
    546 extern FLAC_API const unsigned FLAC__STREAM_METADATA_STREAMINFO_TOTAL_SAMPLES_LEN; /**< == 36 (bits) */
    547 extern FLAC_API const unsigned 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 unsigned 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 	unsigned frame_samples;
    583 	/**< The number of samples in the target frame. */
    584 } FLAC__StreamMetadata_SeekPoint;
    585 
    586 extern FLAC_API const unsigned FLAC__STREAM_METADATA_SEEKPOINT_SAMPLE_NUMBER_LEN; /**< == 64 (bits) */
    587 extern FLAC_API const unsigned FLAC__STREAM_METADATA_SEEKPOINT_STREAM_OFFSET_LEN; /**< == 64 (bits) */
    588 extern FLAC_API const unsigned 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 	unsigned 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 unsigned 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 unsigned 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 unsigned FLAC__STREAM_METADATA_CUESHEET_INDEX_OFFSET_LEN; /**< == 64 (bits) */
    658 extern FLAC_API const unsigned FLAC__STREAM_METADATA_CUESHEET_INDEX_NUMBER_LEN; /**< == 8 (bits) */
    659 extern FLAC_API const unsigned 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 	unsigned type:1;
    677 	/**< The track type: 0 for audio, 1 for non-audio. */
    678 
    679 	unsigned 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 unsigned FLAC__STREAM_METADATA_CUESHEET_TRACK_OFFSET_LEN; /**< == 64 (bits) */
    691 extern FLAC_API const unsigned FLAC__STREAM_METADATA_CUESHEET_TRACK_NUMBER_LEN; /**< == 8 (bits) */
    692 extern FLAC_API const unsigned FLAC__STREAM_METADATA_CUESHEET_TRACK_ISRC_LEN; /**< == 12*8 (bits) */
    693 extern FLAC_API const unsigned FLAC__STREAM_METADATA_CUESHEET_TRACK_TYPE_LEN; /**< == 1 (bit) */
    694 extern FLAC_API const unsigned FLAC__STREAM_METADATA_CUESHEET_TRACK_PRE_EMPHASIS_LEN; /**< == 1 (bit) */
    695 extern FLAC_API const unsigned FLAC__STREAM_METADATA_CUESHEET_TRACK_RESERVED_LEN; /**< == 6+13*8 (bits) */
    696 extern FLAC_API const unsigned 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 	unsigned 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 unsigned FLAC__STREAM_METADATA_CUESHEET_MEDIA_CATALOG_NUMBER_LEN; /**< == 128*8 (bits) */
    725 extern FLAC_API const unsigned FLAC__STREAM_METADATA_CUESHEET_LEAD_IN_LEN; /**< == 64 (bits) */
    726 extern FLAC_API const unsigned FLAC__STREAM_METADATA_CUESHEET_IS_CD_LEN; /**< == 1 (bit) */
    727 extern FLAC_API const unsigned FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN; /**< == 7+258*8 (bits) */
    728 extern FLAC_API const unsigned 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 unsigned FLAC__STREAM_METADATA_PICTURE_TYPE_LEN; /**< == 32 (bits) */
    814 extern FLAC_API const unsigned FLAC__STREAM_METADATA_PICTURE_MIME_TYPE_LENGTH_LEN; /**< == 32 (bits) */
    815 extern FLAC_API const unsigned FLAC__STREAM_METADATA_PICTURE_DESCRIPTION_LENGTH_LEN; /**< == 32 (bits) */
    816 extern FLAC_API const unsigned FLAC__STREAM_METADATA_PICTURE_WIDTH_LEN; /**< == 32 (bits) */
    817 extern FLAC_API const unsigned FLAC__STREAM_METADATA_PICTURE_HEIGHT_LEN; /**< == 32 (bits) */
    818 extern FLAC_API const unsigned FLAC__STREAM_METADATA_PICTURE_DEPTH_LEN; /**< == 32 (bits) */
    819 extern FLAC_API const unsigned FLAC__STREAM_METADATA_PICTURE_COLORS_LEN; /**< == 32 (bits) */
    820 extern FLAC_API const unsigned 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 	unsigned 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 unsigned FLAC__STREAM_METADATA_IS_LAST_LEN; /**< == 1 (bit) */
    861 extern FLAC_API const unsigned FLAC__STREAM_METADATA_TYPE_LEN; /**< == 7 (bits) */
    862 extern FLAC_API const unsigned 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(unsigned 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(unsigned blocksize, unsigned 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(unsigned 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 (unsigned)(-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, unsigned 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, unsigned 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 unsigned
    977  *    The number of duplicate seek points converted into placeholders.
    978  */
    979 FLAC_API unsigned 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