format.h

这是著名的TCPMP播放器在WINDWOWS,和WINCE下编译通过的源程序.笔者对其中的LIBMAD库做了针对ARM MPU的优化. 并增加了词幕功能.

 *   present in a stream.
 */
typedef struct {
	unsigned num_points;
	FLAC__StreamMetadata_SeekPoint *points;
} FLAC__StreamMetadata_SeekTable;


/** Vorbis comment entry structure used in VORBIS_COMMENT blocks.  (c.f. <A HREF="../format.html#metadata_block_vorbis_comment">format specification</A>)
 *
 *  For convenience, the APIs maintain a trailing NUL character at the end of
 *  \a entry which is not counted toward \a length, i.e.
 *  \code strlen(entry) == length \endcode
 */
typedef struct {
	FLAC__uint32 length;
	FLAC__byte *entry;
} FLAC__StreamMetadata_VorbisComment_Entry;

extern FLAC_API const unsigned FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN; /**< == 32 (bits) */


/** FLAC VORBIS_COMMENT structure.  (c.f. <A HREF="../format.html#metadata_block_vorbis_comment">format specification</A>)
 */
typedef struct {
	FLAC__StreamMetadata_VorbisComment_Entry vendor_string;
	FLAC__uint32 num_comments;
	FLAC__StreamMetadata_VorbisComment_Entry *comments;
} FLAC__StreamMetadata_VorbisComment;

extern FLAC_API const unsigned FLAC__STREAM_METADATA_VORBIS_COMMENT_NUM_COMMENTS_LEN; /**< == 32 (bits) */


/** FLAC CUESHEET track index structure.  (See the
 * <A HREF="../format.html#cuesheet_track_index">format specification</A> for
 * the full description of each field.)
 */
typedef struct {
	FLAC__uint64 offset;
	/**< Offset in samples, relative to the track offset, of the index
	 * point.
	 */

	FLAC__byte number;
	/**< The index point number. */
} FLAC__StreamMetadata_CueSheet_Index;

extern FLAC_API const unsigned FLAC__STREAM_METADATA_CUESHEET_INDEX_OFFSET_LEN; /**< == 64 (bits) */
extern FLAC_API const unsigned FLAC__STREAM_METADATA_CUESHEET_INDEX_NUMBER_LEN; /**< == 8 (bits) */
extern FLAC_API const unsigned FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN; /**< == 3*8 (bits) */


/** FLAC CUESHEET track structure.  (See the
 * <A HREF="../format.html#cuesheet_track">format specification</A> for
 * the full description of each field.)
 */
typedef struct {
	FLAC__uint64 offset;
	/**< Track offset in samples, relative to the beginning of the FLAC audio stream. */

	FLAC__byte number;
	/**< The track number. */

	char isrc[13];
	/**< Track ISRC.  This is a 12-digit alphanumeric code plus a trailing '\0' */

	unsigned type:1;
	/**< The track type: 0 for audio, 1 for non-audio. */

	unsigned pre_emphasis:1;
	/**< The pre-emphasis flag: 0 for no pre-emphasis, 1 for pre-emphasis. */

	FLAC__byte num_indices;
	/**< The number of track index points. */

	FLAC__StreamMetadata_CueSheet_Index *indices;
	/**< NULL if num_indices == 0, else pointer to array of index points. */

} FLAC__StreamMetadata_CueSheet_Track;

extern FLAC_API const unsigned FLAC__STREAM_METADATA_CUESHEET_TRACK_OFFSET_LEN; /**< == 64 (bits) */
extern FLAC_API const unsigned FLAC__STREAM_METADATA_CUESHEET_TRACK_NUMBER_LEN; /**< == 8 (bits) */
extern FLAC_API const unsigned FLAC__STREAM_METADATA_CUESHEET_TRACK_ISRC_LEN; /**< == 12*8 (bits) */
extern FLAC_API const unsigned FLAC__STREAM_METADATA_CUESHEET_TRACK_TYPE_LEN; /**< == 1 (bit) */
extern FLAC_API const unsigned FLAC__STREAM_METADATA_CUESHEET_TRACK_PRE_EMPHASIS_LEN; /**< == 1 (bit) */
extern FLAC_API const unsigned FLAC__STREAM_METADATA_CUESHEET_TRACK_RESERVED_LEN; /**< == 6+13*8 (bits) */
extern FLAC_API const unsigned FLAC__STREAM_METADATA_CUESHEET_TRACK_NUM_INDICES_LEN; /**< == 8 (bits) */


/** FLAC CUESHEET structure.  (See the
 * <A HREF="../format.html#metadata_block_cuesheet">format specification</A>
 * for the full description of each field.)
 */
typedef struct {
	char media_catalog_number[129];
	/**< Media catalog number, in ASCII printable characters 0x20-0x7e.  In
	 * general, the media catalog number may be 0 to 128 bytes long; any
	 * unused characters should be right-padded with NUL characters.
	 */

	FLAC__uint64 lead_in;
	/**< The number of lead-in samples. */

	FLAC__bool is_cd;
	/**< \c true if CUESHEET corresponds to a Compact Disc, else \c false */

	unsigned num_tracks;
	/**< The number of tracks. */

	FLAC__StreamMetadata_CueSheet_Track *tracks;
	/**< NULL if num_tracks == 0, else pointer to array of tracks. */

} FLAC__StreamMetadata_CueSheet;

extern FLAC_API const unsigned FLAC__STREAM_METADATA_CUESHEET_MEDIA_CATALOG_NUMBER_LEN; /**< == 128*8 (bits) */
extern FLAC_API const unsigned FLAC__STREAM_METADATA_CUESHEET_LEAD_IN_LEN; /**< == 64 (bits) */
extern FLAC_API const unsigned FLAC__STREAM_METADATA_CUESHEET_IS_CD_LEN; /**< == 1 (bit) */
extern FLAC_API const unsigned FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN; /**< == 7+258*8 (bits) */
extern FLAC_API const unsigned FLAC__STREAM_METADATA_CUESHEET_NUM_TRACKS_LEN; /**< == 8 (bits) */


/** Structure that is used when a metadata block of unknown type is loaded.
 *  The contents are opaque.  The structure is used only internally to
 *  correctly handle unknown metadata.
 */
typedef struct {
	FLAC__byte *data;
} FLAC__StreamMetadata_Unknown;


/** FLAC metadata block structure.  (c.f. <A HREF="../format.html#metadata_block">format specification</A>)
 */
typedef struct {
	FLAC__MetadataType type;
	/**< The type of the metadata block; used determine which member of the
	 * \a data union to dereference.  If type >= FLAC__METADATA_TYPE_UNDEFINED
	 * then \a data.unknown must be used. */

	FLAC__bool is_last;
	/**< \c true if this metadata block is the last, else \a false */

	unsigned length;
	/**< Length, in bytes, of the block data as it appears in the stream. */

	union {
		FLAC__StreamMetadata_StreamInfo stream_info;
		FLAC__StreamMetadata_Padding padding;
		FLAC__StreamMetadata_Application application;
		FLAC__StreamMetadata_SeekTable seek_table;
		FLAC__StreamMetadata_VorbisComment vorbis_comment;
		FLAC__StreamMetadata_CueSheet cue_sheet;
		FLAC__StreamMetadata_Unknown unknown;
	} data;
	/**< Polymorphic block data; use the \a type value to determine which
	 * to use. */
} FLAC__StreamMetadata;

extern FLAC_API const unsigned FLAC__STREAM_METADATA_IS_LAST_LEN; /**< == 1 (bit) */
extern FLAC_API const unsigned FLAC__STREAM_METADATA_TYPE_LEN; /**< == 7 (bits) */
extern FLAC_API const unsigned FLAC__STREAM_METADATA_LENGTH_LEN; /**< == 24 (bits) */

/** The total stream length of a metadata block header in bytes. */
#define FLAC__STREAM_METADATA_HEADER_LENGTH (4u)

/*****************************************************************************/


/*****************************************************************************
 *
 * Utility functions
 *
 *****************************************************************************/

/** Tests that a sample rate is valid for FLAC.  Since the rules for valid
 *  sample rates are slightly complex, they are encapsulated in this function.
 *
 * \param sample_rate  The sample rate to test for compliance.
 * \retval FLAC__bool
 *    \c true if the given sample rate conforms to the specification, else
 *    \c false.
 */
FLAC_API FLAC__bool FLAC__format_sample_rate_is_valid(unsigned sample_rate);

/** Check a Vorbis comment entry name to see if it conforms to the Vorbis
 *  comment specification.
 *
 *  Vorbis comment names must be composed only of characters from
 *  [0x20-0x3C,0x3E-0x7D].
 *
 * \param name       A NUL-terminated string to be checked.
 * \assert
 *    \code name != NULL \endcode
 * \retval FLAC__bool
 *    \c false if entry name is illegal, else \c true.
 */
FLAC_API FLAC__bool FLAC__format_vorbiscomment_entry_name_is_legal(const char *name);

/** Check a Vorbis comment entry value to see if it conforms to the Vorbis
 *  comment specification.
 *
 *  Vorbis comment values must be valid UTF-8 sequences.
 *
 * \param value      A string to be checked.
 * \param length     A the length of \a value in bytes.  May be
 *                   \c (unsigned)(-1) to indicate that \a value is a plain
 *                   UTF-8 NUL-terminated string.
 * \assert
 *    \code value != NULL \endcode
 * \retval FLAC__bool
 *    \c false if entry name is illegal, else \c true.
 */
FLAC_API FLAC__bool FLAC__format_vorbiscomment_entry_value_is_legal(const FLAC__byte *value, unsigned length);

/** Check a Vorbis comment entry to see if it conforms to the Vorbis
 *  comment specification.
 *
 *  Vorbis comment entries must be of the form 'name=value', and 'name' and
 *  'value' must be legal according to
 *  FLAC__format_vorbiscomment_entry_name_is_legal() and
 *  FLAC__format_vorbiscomment_entry_value_is_legal() respectively.
 *
 * \param value      A string to be checked.
 * \assert
 *    \code value != NULL \endcode
 * \retval FLAC__bool
 *    \c false if entry name is illegal, else \c true.
 */
FLAC_API FLAC__bool FLAC__format_vorbiscomment_entry_is_legal(const FLAC__byte *entry, unsigned length);

/* @@@@ add to unit tests; it is already indirectly tested by the metadata_object tests */
/** Check a seek table to see if it conforms to the FLAC specification.
 *  See the format specification for limits on the contents of the
 *  seek table.
 *
 * \param seek_table  A pointer to a seek table to be checked.
 * \assert
 *    \code seek_table != NULL \endcode
 * \retval FLAC__bool
 *    \c false if seek table is illegal, else \c true.
 */
FLAC_API FLAC__bool FLAC__format_seektable_is_legal(const FLAC__StreamMetadata_SeekTable *seek_table);

/* @@@@ add to unit tests; it is already indirectly tested by the metadata_object tests */
/** Sort a seek table's seek points according to the format specification.
 *  This includes a "unique-ification" step to remove duplicates, i.e.
 *  seek points with identical \a sample_number values.  Duplicate seek
 *  points are converted into placeholder points and sorted to the end of
 *  the table.
 *
 * \param seek_table  A pointer to a seek table to be sorted.
 * \assert
 *    \code seek_table != NULL \endcode
 * \retval unsigned
 *    The number of duplicate seek points converted into placeholders.
 */
FLAC_API unsigned FLAC__format_seektable_sort(FLAC__StreamMetadata_SeekTable *seek_table);

/* @@@@ add to unit tests; it is already indirectly tested by the metadata_object tests */
/** Check a cue sheet to see if it conforms to the FLAC specification.
 *  See the format specification for limits on the contents of the
 *  cue sheet.
 *
 * \param cue_sheet  A pointer to an existing cue sheet to be checked.
 * \param check_cd_da_subset  If \c true, check CUESHEET against more
 *                   stringent requirements for a CD-DA (audio) disc.
 * \param violation  Address of a pointer to a string.  If there is a
 *                   violation, a pointer to a string explanation of the
 *                   violation will be returned here. \a violation may be
 *                   \c NULL if you don't need the returned string.  Do not
 *                   free the returned string; it will always point to static
 *                   data.
 * \assert
 *    \code cue_sheet != NULL \endcode
 * \retval FLAC__bool
 *    \c false if cue sheet is illegal, else \c true.
 */
FLAC_API FLAC__bool FLAC__format_cuesheet_is_legal(const FLAC__StreamMetadata_CueSheet *cue_sheet, FLAC__bool check_cd_da_subset, const char **violation);

/* \} */

#ifdef __cplusplus
}
#endif

#endif