format.h

在x86平台上运行不可信任代码的sandbox。

	const FLAC__int32 *residual;
	/**< The residual signal, length == (blocksize minus order) samples. */
} FLAC__Subframe_Fixed;


/** LPC subframe.  (c.f. <A HREF="../format.html#subframe_lpc">format specification</A>)
 */
typedef struct {
	FLAC__EntropyCodingMethod entropy_coding_method;
	/**< The residual coding method. */

	unsigned order;
	/**< The FIR order. */

	unsigned qlp_coeff_precision;
	/**< Quantized FIR filter coefficient precision in bits. */

	int quantization_level;
	/**< The qlp coeff shift needed. */

	FLAC__int32 qlp_coeff[FLAC__MAX_LPC_ORDER];
	/**< FIR filter coefficients. */

	FLAC__int32 warmup[FLAC__MAX_LPC_ORDER];
	/**< Warmup samples to prime the predictor, length == order. */

	const FLAC__int32 *residual;
	/**< The residual signal, length == (blocksize minus order) samples. */
} FLAC__Subframe_LPC;

extern FLAC_API const unsigned FLAC__SUBFRAME_LPC_QLP_COEFF_PRECISION_LEN; /**< == 4 (bits) */
extern FLAC_API const unsigned FLAC__SUBFRAME_LPC_QLP_SHIFT_LEN; /**< == 5 (bits) */


/** FLAC subframe structure.  (c.f. <A HREF="../format.html#subframe">format specification</A>)
 */
typedef struct {
	FLAC__SubframeType type;
	union {
		FLAC__Subframe_Constant constant;
		FLAC__Subframe_Fixed fixed;
		FLAC__Subframe_LPC lpc;
		FLAC__Subframe_Verbatim verbatim;
	} data;
	unsigned wasted_bits;
} FLAC__Subframe;

extern FLAC_API const unsigned FLAC__SUBFRAME_ZERO_PAD_LEN; /**< == 1 (bit) */
extern FLAC_API const unsigned FLAC__SUBFRAME_TYPE_LEN; /**< == 6 (bits) */
extern FLAC_API const unsigned FLAC__SUBFRAME_WASTED_BITS_FLAG_LEN; /**< == 1 (bit) */

extern FLAC_API const unsigned FLAC__SUBFRAME_TYPE_CONSTANT_BYTE_ALIGNED_MASK; /* = 0x00 */
extern FLAC_API const unsigned FLAC__SUBFRAME_TYPE_VERBATIM_BYTE_ALIGNED_MASK; /* = 0x02 */
extern FLAC_API const unsigned FLAC__SUBFRAME_TYPE_FIXED_BYTE_ALIGNED_MASK; /* = 0x10 */
extern FLAC_API const unsigned FLAC__SUBFRAME_TYPE_LPC_BYTE_ALIGNED_MASK; /* = 0x40 */

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


/*****************************************************************************
 *
 * Frame structures
 *
 *****************************************************************************/

/** An enumeration of the available channel assignments. */
typedef enum {
	FLAC__CHANNEL_ASSIGNMENT_INDEPENDENT = 0, /**< independent channels */
	FLAC__CHANNEL_ASSIGNMENT_LEFT_SIDE = 1, /**< left+side stereo */
	FLAC__CHANNEL_ASSIGNMENT_RIGHT_SIDE = 2, /**< right+side stereo */
	FLAC__CHANNEL_ASSIGNMENT_MID_SIDE = 3 /**< mid+side stereo */
} FLAC__ChannelAssignment;

/** Maps a FLAC__ChannelAssignment to a C string.
 *
 *  Using a FLAC__ChannelAssignment as the index to this array will
 *  give the string equivalent.  The contents should not be modified.
 */
extern FLAC_API const char * const FLAC__ChannelAssignmentString[];

/** An enumeration of the possible frame numbering methods. */
typedef enum {
	FLAC__FRAME_NUMBER_TYPE_FRAME_NUMBER, /**< number contains the frame number */
	FLAC__FRAME_NUMBER_TYPE_SAMPLE_NUMBER /**< number contains the sample number of first sample in frame */
} FLAC__FrameNumberType;

/** Maps a FLAC__FrameNumberType to a C string.
 *
 *  Using a FLAC__FrameNumberType as the index to this array will
 *  give the string equivalent.  The contents should not be modified.
 */
extern FLAC_API const char * const FLAC__FrameNumberTypeString[];


/** FLAC frame header structure.  (c.f. <A HREF="../format.html#frame_header">format specification</A>)
 */
typedef struct {
	unsigned blocksize;
	/**< The number of samples per subframe. */

	unsigned sample_rate;
	/**< The sample rate in Hz. */

	unsigned channels;
	/**< The number of channels (== number of subframes). */

	FLAC__ChannelAssignment channel_assignment;
	/**< The channel assignment for the frame. */

	unsigned bits_per_sample;
	/**< The sample resolution. */

	FLAC__FrameNumberType number_type;
	/**< The numbering scheme used for the frame. */

	union {
		FLAC__uint32 frame_number;
		FLAC__uint64 sample_number;
	} number;
	/**< The frame number or sample number of first sample in frame;
	 * use the \a number_type value to determine which to use. */

	FLAC__uint8 crc;
	/**< CRC-8 (polynomial = x^8 + x^2 + x^1 + x^0, initialized with 0)
	 * of the raw frame header bytes, meaning everything before the CRC byte
	 * including the sync code.
	 */
} FLAC__FrameHeader;

extern FLAC_API const unsigned FLAC__FRAME_HEADER_SYNC; /**< == 0x3ffe; the frame header sync code */
extern FLAC_API const unsigned FLAC__FRAME_HEADER_SYNC_LEN; /**< == 14 (bits) */
extern FLAC_API const unsigned FLAC__FRAME_HEADER_RESERVED_LEN; /**< == 2 (bits) */
extern FLAC_API const unsigned FLAC__FRAME_HEADER_BLOCK_SIZE_LEN; /**< == 4 (bits) */
extern FLAC_API const unsigned FLAC__FRAME_HEADER_SAMPLE_RATE_LEN; /**< == 4 (bits) */
extern FLAC_API const unsigned FLAC__FRAME_HEADER_CHANNEL_ASSIGNMENT_LEN; /**< == 4 (bits) */
extern FLAC_API const unsigned FLAC__FRAME_HEADER_BITS_PER_SAMPLE_LEN; /**< == 3 (bits) */
extern FLAC_API const unsigned FLAC__FRAME_HEADER_ZERO_PAD_LEN; /**< == 1 (bit) */
extern FLAC_API const unsigned FLAC__FRAME_HEADER_CRC_LEN; /**< == 8 (bits) */


/** FLAC frame footer structure.  (c.f. <A HREF="../format.html#frame_footer">format specification</A>)
 */
typedef struct {
	FLAC__uint16 crc;
	/**< CRC-16 (polynomial = x^16 + x^15 + x^2 + x^0, initialized with
	 * 0) of the bytes before the crc, back to and including the frame header
	 * sync code.
	 */
} FLAC__FrameFooter;

extern FLAC_API const unsigned FLAC__FRAME_FOOTER_CRC_LEN; /**< == 16 (bits) */


/** FLAC frame structure.  (c.f. <A HREF="../format.html#frame">format specification</A>)
 */
typedef struct {
	FLAC__FrameHeader header;
	FLAC__Subframe subframes[FLAC__MAX_CHANNELS];
	FLAC__FrameFooter footer;
} FLAC__Frame;

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


/*****************************************************************************
 *
 * Meta-data structures
 *
 *****************************************************************************/

/** An enumeration of the available metadata block types. */
typedef enum {

	FLAC__METADATA_TYPE_STREAMINFO = 0,
	/**< <A HREF="../format.html#metadata_block_streaminfo">STREAMINFO</A> block */

	FLAC__METADATA_TYPE_PADDING = 1,
	/**< <A HREF="../format.html#metadata_block_padding">PADDING</A> block */

	FLAC__METADATA_TYPE_APPLICATION = 2,
	/**< <A HREF="../format.html#metadata_block_application">APPLICATION</A> block */

	FLAC__METADATA_TYPE_SEEKTABLE = 3,
	/**< <A HREF="../format.html#metadata_block_seektable">SEEKTABLE</A> block */

	FLAC__METADATA_TYPE_VORBIS_COMMENT = 4,
	/**< <A HREF="../format.html#metadata_block_vorbis_comment">VORBISCOMMENT</A> block */

	FLAC__METADATA_TYPE_CUESHEET = 5,
	/**< <A HREF="../format.html#metadata_block_cuesheet">CUESHEET</A> block */

	FLAC__METADATA_TYPE_UNDEFINED = 6
	/**< marker to denote beginning of undefined type range; this number will increase as new metadata types are added */

} FLAC__MetadataType;

/** Maps a FLAC__MetadataType to a C string.
 *
 *  Using a FLAC__MetadataType as the index to this array will
 *  give the string equivalent.  The contents should not be modified.
 */
extern FLAC_API const char * const FLAC__MetadataTypeString[];


/** FLAC STREAMINFO structure.  (c.f. <A HREF="../format.html#metadata_block_streaminfo">format specification</A>)
 */
typedef struct {
	unsigned min_blocksize, max_blocksize;
	unsigned min_framesize, max_framesize;
	unsigned sample_rate;
	unsigned channels;
	unsigned bits_per_sample;
	FLAC__uint64 total_samples;
	FLAC__byte md5sum[16];
} FLAC__StreamMetadata_StreamInfo;

extern FLAC_API const unsigned FLAC__STREAM_METADATA_STREAMINFO_MIN_BLOCK_SIZE_LEN; /**< == 16 (bits) */
extern FLAC_API const unsigned FLAC__STREAM_METADATA_STREAMINFO_MAX_BLOCK_SIZE_LEN; /**< == 16 (bits) */
extern FLAC_API const unsigned FLAC__STREAM_METADATA_STREAMINFO_MIN_FRAME_SIZE_LEN; /**< == 24 (bits) */
extern FLAC_API const unsigned FLAC__STREAM_METADATA_STREAMINFO_MAX_FRAME_SIZE_LEN; /**< == 24 (bits) */
extern FLAC_API const unsigned FLAC__STREAM_METADATA_STREAMINFO_SAMPLE_RATE_LEN; /**< == 20 (bits) */
extern FLAC_API const unsigned FLAC__STREAM_METADATA_STREAMINFO_CHANNELS_LEN; /**< == 3 (bits) */
extern FLAC_API const unsigned FLAC__STREAM_METADATA_STREAMINFO_BITS_PER_SAMPLE_LEN; /**< == 5 (bits) */
extern FLAC_API const unsigned FLAC__STREAM_METADATA_STREAMINFO_TOTAL_SAMPLES_LEN; /**< == 36 (bits) */
extern FLAC_API const unsigned FLAC__STREAM_METADATA_STREAMINFO_MD5SUM_LEN; /**< == 128 (bits) */

/** The total stream length of the STREAMINFO block in bytes. */
#define FLAC__STREAM_METADATA_STREAMINFO_LENGTH (34u)

/** FLAC PADDING structure.  (c.f. <A HREF="../format.html#metadata_block_padding">format specification</A>)
 */
typedef struct {
	int dummy;
	/**< Conceptually this is an empty struct since we don't store the
	 * padding bytes.  Empty structs are not allowed by some C compilers,
	 * hence the dummy.
	 */
} FLAC__StreamMetadata_Padding;


/** FLAC APPLICATION structure.  (c.f. <A HREF="../format.html#metadata_block_application">format specification</A>)
 */
typedef struct {
	FLAC__byte id[4];
	FLAC__byte *data;
} FLAC__StreamMetadata_Application;

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

/** SeekPoint structure used in SEEKTABLE blocks.  (c.f. <A HREF="../format.html#seekpoint">format specification</A>)
 */
typedef struct {
	FLAC__uint64 sample_number;
	/**<  The sample number of the target frame. */

	FLAC__uint64 stream_offset;
	/**< The offset, in bytes, of the target frame with respect to
	 * beginning of the first frame. */

	unsigned frame_samples;
	/**< The number of samples in the target frame. */
} FLAC__StreamMetadata_SeekPoint;

extern FLAC_API const unsigned FLAC__STREAM_METADATA_SEEKPOINT_SAMPLE_NUMBER_LEN; /**< == 64 (bits) */
extern FLAC_API const unsigned FLAC__STREAM_METADATA_SEEKPOINT_STREAM_OFFSET_LEN; /**< == 64 (bits) */
extern FLAC_API const unsigned FLAC__STREAM_METADATA_SEEKPOINT_FRAME_SAMPLES_LEN; /**< == 16 (bits) */

/** The total stream length of a seek point in bytes. */
#define FLAC__STREAM_METADATA_SEEKPOINT_LENGTH (18u)

/** The value used in the \a sample_number field of
 *  FLAC__StreamMetadataSeekPoint used to indicate a placeholder
 *  point (== 0xffffffffffffffff).
 */
extern FLAC_API const FLAC__uint64 FLAC__STREAM_METADATA_SEEKPOINT_PLACEHOLDER;


/** FLAC SEEKTABLE structure.  (c.f. <A HREF="../format.html#metadata_block_seektable">format specification</A>)
 *
 * \note From the format specification:
 * - The seek points must be sorted by ascending sample number.
 * - Each seek point's sample number must be the first sample of the
 *   target frame.
 * - Each seek point's sample number must be unique within the table.
 * - Existence of a SEEKTABLE block implies a correct setting of
 *   total_samples in the stream_info block.
 * - Behavior is undefined when more than one SEEKTABLE block is