/*
* libfoxenflac -- Tiny FLAC Decoder Library
* Copyright (C) 2018-2022 Andreas Stöckel
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see .
*/
#include
#include
#include
#include
#include
#if 0
/* Set FX_FLAC_NO_CRC if you control the input data and already performed other
integrity checks. This makes the decoder significantly faster. */
#define FX_FLAC_NO_CRC
#endif
/******************************************************************************
* CODE MERGED FROM OTHER LIBFOXEN PROJECTS *
******************************************************************************/
/******************************************************************************
* Copy of foxen/bitstream.h *
******************************************************************************/
/**
* Structure holding the current state of the bitstream reader.
*/
struct fx_bitstream {
/**
* 64 bit word from which the data is extracted.
*/
uint64_t buf;
/**
* Pointer at the source byte stream.
*/
uint8_t const *src;
/**
* Pointer at the end of the source byte stream.
*/
uint8_t const *src_end;
/**
* Position within the source byte stream in bits, i.e. the number of bits
* that have been consumed.
*/
uint8_t pos;
};
/**
* Typedef for the fx_bitstream struct.
*/
typedef struct fx_bitstream fx_bitstream_t;
/**
* Callback called whenever a fully byte has been consumed. This is useful for
* CRC calculations.
*/
typedef void (*fx_bitstream_byte_callback_t)(uint8_t byte, void *data);
/**
* Initializes the bitstream reader instance. Call fx_bitstream_set_source()
* to set the byte buffer from which the bitstream reader should read its
* data.
*
* @param reader is the bitstream reader instance that should be
* initialized.
*/
static inline void fx_bitstream_init(fx_bitstream_t *reader) {
reader->buf = 0U;
reader->pos = sizeof(reader->buf) * 8U;
reader->src = NULL;
reader->src_end = NULL;
}
/**
* Sets the backing source buffer for the bitstream. This function may only be
* called if the given pointer is a direct continuation of the previous data,
* i.e. are essentially set to reader->src.
*
* @param reader is the bitstream reader instance for which the source byte
* buffer should be set.
* @param src is a pointer at the source byte buffer.
* @param src_len is the length of the source byte buffer in bytes.
*/
static inline void fx_bitstream_set_source(fx_bitstream_t *reader,
const uint8_t *src,
uint32_t src_len);
/**
* Returns true if the corresponding read operation will be successful.
*
* @param reader is the bitstream reader instance from which the data should be
* read.
* @param n_bits is the number of bits that should be read from the bitstream
* reader. Must be in 1 <= n_bits <= 57.
* @return true if the number of available bits is smaller or equal to n_bits.
*/
static inline bool fx_bitstream_can_read(fx_bitstream_t *reader,
uint8_t n_bits) {
return (sizeof(reader->buf) * 8U) >= (n_bits + reader->pos);
}
/**
* Reads up to 64 bits from the input buffer in MSB order. Note that this
* function does not check whether the read operation returns valid data, so
* make sure to call fx_bitstream_can_read() before reading.
*
* @param reader is the bitstream reader instance from which the data should be
* read.
* @param n_bits is the number of bits that should be read. Must be in
* 1 <= n_bits <= 57.
* @return an integer corresponding the the specified number of bits.
*/
static inline uint64_t fx_bitstream_read_msb(fx_bitstream_t *reader,
uint8_t n_bits);
/**
* Reads up to 64 bits from the input buffer in MSB order. Note that this
* function does not check whether the read operation returns valid data, so
* make sure to call fx_bitstream_can_read() before reading.
*
* @param reader is the bitstream reader instance from which the data should be
* read.
* @param n_bits is the number of bits that should be read. Must be in
* 1 <= n_bits <= 57.
* @param callback is called whenever a full byte is consumed. Note that this
* includes a "virtual" set of zeros at the beginning of the bitstream.
* @param callback_data is a user-defined pointer passed to the byte callback.
* @return an integer corresponding the the specified number of bits.
*/
static inline uint64_t fx_bitstream_read_msb_ex(
fx_bitstream_t *reader, uint8_t n_bits,
fx_bitstream_byte_callback_t callback, void *callback_data);
/**
* Reads up to 64 bits from the input buffer in MSB order without advancing the
* buffer location. Note that this function does not check whether the read
* operation returns valid data, so make sure to call fx_bitstream_can_read()
* before reading.
*
* @param reader is the bitstream reader instance from which the data should be
* read.
* @param n_bits is the number of bits that should be read. Must be in
* 1 <= n_bits <= 57.
* @return an integer corresponding to the specified number of bits.
*/
static inline uint64_t fx_bitstream_peek_msb(fx_bitstream_t *reader,
uint8_t n_bits);
/**
* Combination of fx_bitstream_can_read and fx_bitstream_read_msb. Returns a
* negative value if the desired number of bits cannot be read from the source.
* If the given number of threads are available, returns the desired integer.
*
* @param reads is the bitstream reader instance from which the data should be
* read.
* @param n_bits is the number of bits that should be read. Must be in
* 1 <= n_bits <= 57.
* @return -1 if the desired number of bits is not available in the bitstream.
* Otherwise the integer corresponding to the specified number of bits is
* returned.
*/
static inline int64_t fx_bitstream_try_read_msb(fx_bitstream_t *reader,
uint8_t n_bits) {
return fx_bitstream_can_read(reader, n_bits)
? (int64_t)fx_bitstream_read_msb(reader, n_bits)
: -1;
}
/**
* Combination of fx_bitstream_can_read and fx_bitstream_read_msb. Returns a
* negative value if the desired number of bits cannot be read from the source.
* If the given number of threads are available, returns the desired integer.
*
* @param reads is the bitstream reader instance from which the data should be
* read.
* @param n_bits is the number of bits that should be read. Must be in
* 1 <= n_bits <= 57.
* @param callback is called whenever a full byte is consumed. Note that this
* includes a "virtual" set of zeros at the beginning of the bitstream.
* @param callback_data is a user-defined pointer passed to the byte callback.
* @return -1 if the desired number of bits is not available in the bitstream.
* Otherwise the integer corresponding to the specified number of bits is
* returned.
*/
static inline int64_t fx_bitstream_try_read_msb_ex(
fx_bitstream_t *reader, uint8_t n_bits,
fx_bitstream_byte_callback_t callback, void *callback_data) {
return fx_bitstream_can_read(reader, n_bits)
? (int64_t)fx_bitstream_read_msb_ex(reader, n_bits, callback,
callback_data)
: -1;
}
/**
* Combination of fx_bitstream_can_read and fx_bitstream_peek. Returns a
* negative value if the desired number of bits cannot be read from the source.
* If the given number of threads are available, returns the desired integer.
* In contrast to fx_bitstream_try_read_msb() this function does not advance
* the actual reader pointer.
*
* @param reads is the bitstream reader instance from which the data should be
* read.
* @param n_bits is the number of bits that should be read. Must be in
* 1 <= n_bits <= 57.
* @return -1 if the desired number of bits is not available in the bitstream.
* Otherwise the integer corresponding to the specified number of bits is
* returned.
*/
static inline int64_t fx_bitstream_try_peek_msb(fx_bitstream_t *reader,
uint8_t n_bits) {
return fx_bitstream_can_read(reader, n_bits)
? (int64_t)fx_bitstream_peek_msb(reader, n_bits)
: -1;
}
#define BUFSIZE (sizeof(((fx_bitstream_t *)NULL)->buf) * 8U)
static inline void _fx_bitstream_fill_buf(fx_bitstream_t *reader) {
while (reader->pos >= 8U && reader->src != reader->src_end) {
reader->buf = (reader->buf << 8U) | *(reader->src++);
reader->pos -= 8U;
}
}
static inline uint64_t _fx_bitstream_read_msb(
fx_bitstream_t *reader, uint8_t n_bits,
fx_bitstream_byte_callback_t callback, void *callback_data) {
assert((n_bits >= 1U) && (n_bits <= (BUFSIZE - 7U)));
/* Copy the current buffer content, skip already read bits */
uint64_t bits = reader->buf << reader->pos;
/* If the callback is specified, issue bytes that were read entirely */
const uint8_t pos_new = reader->pos + n_bits;
if (callback) {
const uint8_t i0 = reader->pos / 8U, i1 = pos_new / 8U;
uint64_t buf = reader->buf << (i0 * 8U);
for (uint8_t i = i0; i < i1; i++) {
uint8_t byte = buf >> (BUFSIZE - 8U);
callback(byte, callback_data);
buf = buf << 8U;
}
}
/* Advance the position */
reader->pos = pos_new;
/* Read new bytes from the byte stream */
_fx_bitstream_fill_buf(reader);
/* Mask out the "low" bits */
return bits >> (BUFSIZE - n_bits);
}
static inline void fx_bitstream_set_source(fx_bitstream_t *reader,
const uint8_t *src,
uint32_t src_len) {
reader->src = src;
reader->src_end = src + src_len;
_fx_bitstream_fill_buf(reader);
}
static inline uint64_t fx_bitstream_read_msb(fx_bitstream_t *reader,
uint8_t n_bits) {
return _fx_bitstream_read_msb(reader, n_bits, NULL, NULL);
}
static inline uint64_t fx_bitstream_read_msb_ex(
fx_bitstream_t *reader, uint8_t n_bits,
fx_bitstream_byte_callback_t callback, void *callback_data) {
return _fx_bitstream_read_msb(reader, n_bits, callback, callback_data);
}
static inline uint64_t fx_bitstream_peek_msb(fx_bitstream_t *reader,
uint8_t n_bits) {
assert((n_bits >= 1U) && (n_bits <= (BUFSIZE - 7U)));
return (reader->buf << reader->pos) >> (BUFSIZE - n_bits);
}
/******************************************************************************
* Copy of foxen/mem.h *
******************************************************************************/
/**
* Memory alignment for pointers internally used by Stanchion. Aligning memory
* and telling the compiler about it allows the compiler to perform better
* optimization. Furthermore, some platforms (WASM) do not allow unaligned
* memory access.
*/
#define FX_ALIGN 1
/**
* Macro telling the compiler that P is aligned with the specified alignment
* ALIGN.
*/
#define FX_ASSUME_ALIGNED_EX(P, ALIGN) P
#ifdef __GNUC__
#if (__GNUC__ == 4 && __GNUC_MINOR__ >= 7) || (__GNUC__ > 4)
#undef FX_ASSUME_ALIGNED_EX
#define FX_ASSUME_ALIGNED_EX(P, ALIGN) (__builtin_assume_aligned(P, ALIGN))
#endif /* (__GNUC__ == 4 && __GNUC_MINOR__ >= 7) || (__GNUC__ > 4) */
#endif /* __GNUC__ */
/**
* Macro telling the compiler that P is aligned with the alignment defined
* above.
*/
#define FX_ASSUME_ALIGNED(P) FX_ASSUME_ALIGNED_EX(P, FX_ALIGN)
/**
* Forces a pointer to have the specified alignment.
*/
#define FX_ALIGN_ADDR_EX(P, ALIGN) \
(FX_ASSUME_ALIGNED_EX( \
(void *)(((uintptr_t)(P) + ALIGN - 1) & (~(uintptr_t)(ALIGN - 1))), \
ALIGN))
/**
* Forces a pointer to have the alignment defined above.
*/
#define FX_ALIGN_ADDR(P) FX_ALIGN_ADDR_EX(P, FX_ALIGN)
/**
* Macro that fills the structure pointed at by P with zeros. See
* fx_mem_zero_aligned() regarding potential dangers.
*/
#define FX_MEM_ZERO_ALIGNED(P) \
do { \
fx_mem_zero_aligned(P, sizeof(*(P))); \
} while (0)
/**
* Call this first in a chain of fx_mem_update_size() calls. It will make sure
* that there is enough space to align the datastructure whenever the user
* provides a non-aligned target memory pointer.
*
* @param size is a pointer at a variable that holds the size of the object
* that we're describing. This function initializes this value to FX_ALIGN - 1.
* @return Always returns true to facilitate chaining with other fx_mem_*_size()
* functions.
*/
static inline bool fx_mem_init_size(uint32_t *size) {
*size = FX_ALIGN;
return true;
}
/**
* Function used to compute the total size of a datastructure consisting of
* multiple substructures. Calling this function updates the size of the outer
* datastructure by adding a substructure of size n_bytes. Assumes that the
* beginning of the substructure must be aligned to the given alignment.
*
* @param size is a pointer at the variable holding the size of the
* datastructure. This must always be a multiple of FX_ALIGN.
* @param n_bytes size of the sub-structure that should be added.
* @return zero if there was an overflow, one otherwise.
*/
static inline bool fx_mem_update_size_ex(uint32_t *size, uint32_t n_bytes,
uint32_t align) {
const uint32_t new_size = ((*size + n_bytes + align - 1) & (~(align - 1)));
if (new_size < *size) {
return false; /* error, there has been an overflow */
}
*size = new_size;
return true; /* success */
}
/**
* Function used to compute the total size of a datastructure consisting of
* multiple substructures. Calling this function updates the size of the outer
* datastructure by adding a substructure of size n_bytes. Assumes that the
* beginning of the substructure must be aligned to the default alignment.
*
* @param size is a pointer at the variable holding the size of the
* datastructure. This must always be a multiple of FX_ALIGN.
* @param n_bytes size of the sub-structure that should be added.
* @return zero if there was an overflow, one otherwise.
*/
static inline bool fx_mem_update_size(uint32_t *size, uint32_t n_bytes) {
return fx_mem_update_size_ex(size, n_bytes, FX_ALIGN);
}
/**
* Computes the aligned pointer pointing at the substructure of the given size
* for the specified alignment.
*
* @param mem pointer at the variable holding the pointer at the current
* pointer. The pointer is advanced by the given size after the return value is
* computed.
* @param size is the size of the substructure for which the pointer should be
* returned.
* @param align is the memory alignment to use.
* @return an aligned pointer pointing at the beginning of the substructure.
*/
static inline void *fx_mem_align_ex(void **mem, uint32_t size, uint32_t align) {
void *res = FX_ALIGN_ADDR_EX(*mem, align);
*mem = (void *)((uintptr_t)res + size);
return res;
}
/**
* Computes the default-aligned pointer pointing at the substructure of the
* given size.
*
* @param mem pointer at the variable holding the pointer at the current
* pointer. The pointer is advanced by the given size after the return value is
* computed.
* @param size is the size of the substructure for which the pointer should be
* returned.
* @return an aligned pointer pointing at the beginning of the substructure.
*/
static inline void *fx_mem_align(void **mem, uint32_t size) {
return fx_mem_align_ex(mem, size, FX_ALIGN);
}
/**
* Fills the given memory region with zeros. In contrast to memset(mem, 0, size)
* this assumes that the pointer is at least aligned at the FX_ALIGN boundary
* and that we can write multiples of FX_ALIGN bytes at once. This is
* potentially dangerous, so do not use this function if you don't know exactly
* what you're doing.
*
* @param mem is a pointer at the memory region that should be zeroed out. This
* pointer is assumed to be aligned.
* @param size is the size of the memory region that should be zeroed in bytes.
* This value is effectively rounded up to a multiple of FX_ALIGN
*/
static inline void fx_mem_zero_aligned(void *mem, uint32_t size) {
assert((((uintptr_t)mem) & (FX_ALIGN - 1)) == 0); /* mem must be aligned */
mem = FX_ASSUME_ALIGNED(mem);
for (uint32_t i = 0; i < (size + FX_ALIGN - 1) / FX_ALIGN; i++) {
((uint64_t *)mem)[2 * i + 0] = 0; /* If we're lucky, this loop is */
((uint64_t *)mem)[2 * i + 1] = 0; /* unrolled and vectorised. */
}
}
/******************************************************************************
* DATATYPES *
******************************************************************************/
/******************************************************************************
* Enums and constants defined in the FLAC format specifiction *
******************************************************************************/
/**
* Possible metadata block types.
*/
typedef enum {
META_TYPE_STREAMINFO = 0,
META_TYPE_PADDING = 1,
META_TYPE_APPLICATION = 2,
META_TYPE_SEEKTABLE = 3,
META_TYPE_VORBIS_COMMENT = 4,
META_TYPE_CUESHEET = 5,
META_TYPE_PICTURE = 6,
META_TYPE_INVALID = 127
} fx_flac_metadata_type_t;
typedef enum { BLK_FIXED = 0, BLK_VARIABLE = 1 } fx_flac_blocking_strategy_t;
typedef enum {
INDEPENDENT_MONO = 0,
INDEPENDENT_STEREO = 1,
INDEPENDENT_3C = 2,
INDEPENDENT_4C = 3,
INDEPENDENT_5C = 4,
INDEPENDENT_6C = 5,
INDEPENDENT_7C = 6,
INDEPENDENT_8C = 7,
LEFT_SIDE_STEREO = 8,
RIGHT_SIDE_STEREO = 9,
MID_SIDE_STEREO = 10,
} fx_flac_channel_assignment_t;
typedef enum {
BLK_SIZE_RESERVED = 0,
BLK_SIZE_192 = 1,
BLK_SIZE_576 = 2,
BLK_SIZE_1152 = 3,
BLK_SIZE_2304 = 4,
BLK_SIZE_4608 = 5,
BLK_SIZE_READ_8BIT = 6,
BLK_SIZE_READ_16BIT = 7,
BLK_SIZE_256 = 8,
BLK_SIZE_512 = 9,
BLK_SIZE_1024 = 10,
BLK_SIZE_2048 = 11,
BLK_SIZE_4096 = 12,
BLK_SIZE_8192 = 13,
BLK_SIZE_16384 = 14,
BLK_SIZE_32768 = 15
} fx_flac_block_size_t;
static const int32_t fx_flac_block_sizes_[] = {
-1, 192, 576, 1152, 2304, 4608, 0, 0,
256, 512, 1024, 2048, 4096, 8192, 16384, 32768};
typedef enum {
FS_STREAMINFO = 0,
FS_88_2KHZ = 1,
FS_176_4KHZ = 2,
FS_192KHZ = 3,
FS_8KHZ = 4,
FS_16KHZ = 5,
FS_22_05KHZ = 6,
FS_24KHZ = 7,
FS_32KHZ = 8,
FS_44_1KHZ = 9,
FS_48KHZ = 10,
FS_96KHZ = 11,
FS_READ_8BIT_KHZ = 12,
FS_READ_16BIT_HZ = 13,
FS_READ_16BIT_DHZ = 14,
FS_INVALID = 15
} fx_flac_sample_rate_t;
static const int32_t fx_flac_sample_rates_[] = {
0, 88200, 176400, 192000, 8000, 16000, 22050, 24000,
32000, 44100, 48000, 96000, 0, 0, 0, -1};
typedef enum {
SS_STREAMINFO = 0,
SS_8BIT = 1,
SS_12BIT = 2,
SS_RESERVED_1 = 3,
SS_16BIT = 4,
SS_20BIT = 5,
SS_24BIT = 6,
SS_RESERVED_2 = 7
} fx_flac_sample_size_t;
static const int8_t fx_flac_sample_sizes_[] = {0, 8, 12, -1, 16, 20, 24, -1};
typedef enum {
SFT_CONSTANT,
SFT_VERBATIM,
SFT_FIXED,
SFT_LPC
} fx_flac_subframe_type_t;
typedef enum {
RES_RICE = 0,
RES_RICE2 = 1,
RES_RESERVED_1 = 2,
RES_RESERVED_2 = 3
} fx_flac_residual_method_t;
/******************************************************************************
* Structs defined in the flac format specification *
******************************************************************************/
/**
* Struc holding all the information stored in an individual block header.
*/
typedef struct {
/**
* Set to 1 if this metadata block is the last metadata block in the
* stream.
*/
bool is_last;
/**
* Type of the metadata block.
*/
fx_flac_metadata_type_t type;
/**
* Length of the metadata block in bytes.
*/
uint32_t length;
} fx_flac_metadata_t;
/**
* Data stored in the STREAMINFO header.
*/
typedef struct {
uint16_t min_block_size;
uint16_t max_block_size;
uint32_t min_frame_size;
uint32_t max_frame_size;
uint32_t sample_rate;
uint8_t n_channels;
uint8_t sample_size;
uint64_t n_samples;
uint8_t md5_sum[16];
} fx_flac_streaminfo_t;
/**
* Frame header prepended to each FLAC audio block.
*/
typedef struct {
fx_flac_blocking_strategy_t blocking_strategy;
fx_flac_block_size_t block_size_enum;
fx_flac_sample_rate_t sample_rate_enum;
fx_flac_channel_assignment_t channel_assignment;
fx_flac_sample_size_t sample_size_enum;
uint32_t block_size;
uint32_t sample_rate;
uint8_t channel_count;
uint8_t sample_size;
uint64_t sync_info;
uint8_t crc8;
} fx_flac_frame_header_t;
/**
* Header prepended to the channel-specific data of each FLAC audio block.
*/
typedef struct {
/**
* Specifies the method used to encode the data.
*/
fx_flac_subframe_type_t type;
/**
* Order of this frame.
*/
uint8_t order;
/**
* Number of bits the decoded result has to be shifted to the left.
*/
uint8_t wasted_bits;
/**
* Number of bits used to encode the linear predictor coefficients.
*/
uint8_t lpc_prec;
/**
* Shift applied to the coefficients.
*/
int8_t lpc_shift;
/**
* LPC coefficients. Number of used coefficients corresponds to the order.
*/
int32_t *lpc_coeffs;
/**
* Method used to code the residual. FLAC currently only supports RICE and
* RICE2.
*/
fx_flac_residual_method_t residual_method;
/**
* Number of partitions the signal is divided into.
*/
uint8_t rice_partition_order;
/**
* RICE parameter, i.e. the logarithm of the divisor.
*/
uint8_t rice_parameter;
} fx_flac_subframe_header_t;
/**
* Array containing the LPC coefficients for the fixed coding mode.
*/
static const int32_t _fx_flac_fixed_coeffs[5][4] = {
{0,0,0,0}, {1,0,0,0}, {2, -1, 0, 0}, {3, -3, 1, 0}, {4, -6, 4, -1}
};
/******************************************************************************
* Internal state machine enums *
******************************************************************************/
/**
* More fine-grained state descriptor used in the internal state machine.
*/
typedef enum {
FLAC_SYNC_INIT = 0,
FLAC_SYNC_F = 100,
FLAC_SYNC_L = 101,
FLAC_SYNC_A = 102,
FLAC_METADATA_HEADER = 200,
FLAC_METADATA_SKIP = 201,
FLAC_METADATA_SINFO = 202,
FLAC_FRAME_SYNC = 300,
FLAC_FRAME_HEADER = 400,
FLAC_FRAME_HEADER_SYNC_INFO = 401,
FLAC_FRAME_HEADER_AUX = 402,
FLAC_FRAME_HEADER_CRC = 403,
FLAC_SUBFRAME_HEADER = 500,
FLAC_SUBFRAME_CONSTANT = 502,
FLAC_SUBFRAME_FIXED = 503,
FLAC_SUBFRAME_FIXED_RESIDUAL = 504,
FLAC_SUBFRAME_LPC = 505,
FLAC_SUBFRAME_LPC_HEADER = 506,
FLAC_SUBFRAME_LPC_COEFFS = 507,
FLAC_SUBFRAME_LPC_RESIDUAL = 508,
FLAC_SUBFRAME_RICE_INIT = 509,
FLAC_SUBFRAME_RICE = 510,
FLAC_SUBFRAME_RICE_UNARY = 511,
FLAC_SUBFRAME_RICE_VERBATIM = 512,
FLAC_SUBFRAME_RICE_FINALIZE = 513,
FLAC_SUBFRAME_VERBATIM = 514,
FLAC_SUBFRAME_FINALIZE = 515
} fx_flac_private_state_t;
/******************************************************************************
* Internal structs *
******************************************************************************/
/**
* Private definition of the fx_flac structure.
*/
struct fx_flac {
/**
* Bitstream reader used to read individual bits from the input.
*/
fx_bitstream_t bitstream;
/**
* Current state of the decoder.
*/
fx_flac_state_t state;
/**
* Current private state of the decoder.
*/
fx_flac_private_state_t priv_state;
/**
* Number of bytes remaining to read for the current frame/block.
*/
uint32_t n_bytes_rem;
/**
* Maximum numbers of samples in a single block, per channel.
*/
uint16_t max_block_size;
/**
* Maximum number of channels supported by the decoder.
*/
uint8_t max_channels;
/**
* Current coefficient.
*/
uint8_t coef_cur;
/**
* Current rice partition.
*/
uint16_t partition_cur;
/**
* Current sample index in the current rice partition (decremented to zero).
*/
uint16_t partition_sample;
/**
* Current rice partition unary quotient counter.
*/
uint16_t rice_unary_counter;
/**
* Current channel. This is reset at frame boundaries.
*/
uint8_t chan_cur;
/**
* Pointer into the current block buffer.
*/
uint16_t blk_cur;
/**
* Variable holding the checksum computed when reading the frame_header.
*/
uint8_t crc8;
/**
* Variable holding the checksum of an entire frame. If this checksum does
* not match after decoding a frame, the entire frame is rejected.
*/
uint16_t crc16;
/**
* Flag indicating whether the current metadata block is the last metadata
* block.
*/
fx_flac_metadata_t *metadata;
/**
* Structure holding the current stream metadata.
*/
fx_flac_streaminfo_t *streaminfo;
/**
* Structure holding the frame header.
*/
fx_flac_frame_header_t *frame_header;
/**
* Structure holding the subframe header.
*/
fx_flac_subframe_header_t *subframe_header;
/**
* Buffer used for storing the LPC coefficients.
*/
int32_t *qbuf;
/**
* Structure holding the temporary/output buffers for each channel.
*/
int32_t *blkbuf[FLAC_MAX_CHANNEL_COUNT];
};
/******************************************************************************
* PRIVATE CODE *
******************************************************************************/
/******************************************************************************
* Initialization code utils *
******************************************************************************/
static bool _fx_flac_check_params(uint16_t max_block_size,
uint8_t max_channels) {
return (max_block_size > 0U) && (max_channels > 0U) &&
(max_channels <= FLAC_MAX_CHANNEL_COUNT);
}
/******************************************************************************
* FLAC enum decoders *
******************************************************************************/
static bool _fx_flac_decode_block_size(fx_flac_block_size_t block_size_enum,
uint32_t *block_size) {
const int32_t bs = fx_flac_block_sizes_[(int)block_size_enum];
if (bs < 0) {
return false; /* Invalid */
} else if (bs > 0) {
*block_size = bs;
}
return true;
}
static bool _fx_flac_decode_sample_rate(fx_flac_sample_rate_t sample_rate_enum,
uint32_t *sample_rate) {
const int32_t fs = fx_flac_sample_rates_[(int)sample_rate_enum];
if (fs < 0) {
return false; /* Invalid */
} else if (fs > 0) {
*sample_rate = fs;
}
return true;
}
static bool _fx_flac_decode_sample_size(fx_flac_sample_size_t sample_size_enum,
uint8_t *sample_size) {
const int8_t ss = fx_flac_sample_sizes_[(int)sample_size_enum];
if (ss < 0) {
return false; /* Invalid */
} else if (ss > 0) {
*sample_size = ss;
}
return true;
}
/**
* Returns the number of channels encoded in the frame header.
*/
static bool _fx_flac_decode_channel_count(
fx_flac_channel_assignment_t channel_assignment, uint8_t *channel_count) {
*channel_count = (channel_assignment >= LEFT_SIDE_STEREO)
? 2U
: (uint8_t)channel_assignment + 1U;
return true;
}
/******************************************************************************
* Decoding functions *
******************************************************************************/
static inline void _fx_flac_post_process_left_side(int32_t *blk1, int32_t *blk2,
uint32_t blk_size) {
blk1 = (int32_t *)FX_ASSUME_ALIGNED(blk1);
blk2 = (int32_t *)FX_ASSUME_ALIGNED(blk2);
for (uint32_t i = 0U; i < blk_size; i++) {
blk2[i] = blk1[i] - blk2[i];
}
}
static inline void _fx_flac_post_process_right_side(int32_t *blk1,
int32_t *blk2,
uint32_t blk_size) {
blk1 = (int32_t *)FX_ASSUME_ALIGNED(blk1);
blk2 = (int32_t *)FX_ASSUME_ALIGNED(blk2);
for (uint32_t i = 0U; i < blk_size; i++) {
blk1[i] = blk1[i] + blk2[i];
}
}
static inline void _fx_flac_post_process_mid_side(int32_t *blk1, int32_t *blk2,
uint32_t blk_size) {
blk1 = (int32_t *)FX_ASSUME_ALIGNED(blk1);
blk2 = (int32_t *)FX_ASSUME_ALIGNED(blk2);
for (uint32_t i = 0U; i < blk_size; i++) {
/* Code libflac from stream_decoder.c */
int32_t mid = blk1[i];
int32_t side = blk2[i];
mid = ((uint32_t)mid) << 1;
mid |= (side & 1); /* Round correctly */
blk1[i] = (mid + side) >> 1;
blk2[i] = (mid - side) >> 1;
}
}
static inline void _fx_flac_restore_lpc_signal(int32_t *blk, uint32_t blk_size,
int32_t *lpc_coeffs,
uint8_t lpc_order,
int8_t lpc_shift) {
blk = (int32_t *)FX_ASSUME_ALIGNED(blk);
lpc_coeffs = (int32_t *)FX_ASSUME_ALIGNED(lpc_coeffs);
for (uint32_t i = lpc_order; i < blk_size; i++) {
int64_t accu = 0;
for (uint8_t j = 0; j < lpc_order; j++) {
accu += (int64_t)lpc_coeffs[j] * (int64_t)blk[i - j - 1];
}
blk[i] = blk[i] + (accu >> lpc_shift);
}
}
/******************************************************************************
* Stream utility functions and macros *
******************************************************************************/
/* http://graphics.stanford.edu/~seander/bithacks.html#FixedSignExtend */
#define SIGN_EXTEND(x, b) \
(int64_t)((x) ^ (1LU << ((b)-1U))) - (int64_t)(1LU << ((b)-1U))
#define ENSURE_BITS(n) \
if (!fx_bitstream_can_read(&inst->bitstream, n)) { \
return false; /* Need more data */ \
}
#define READ_BITS(n) \
(tmp_ = fx_bitstream_try_read_msb(&inst->bitstream, n)); \
if (tmp_ < 0) { \
return false; /* Need more data */ \
}
#define READ_BITS_FAST(n) (tmp_ = fx_bitstream_read_msb(&inst->bitstream, n));
#define PEEK_BITS(n) \
(tmp_ = fx_bitstream_try_peek_msb(&inst->bitstream, n)); \
if (tmp_ < 0) { \
return false; /* Need more data */ \
}
#define SYNC_BYTESTREAM() \
{ \
uint8_t n_ = inst->bitstream.pos & 0x07; \
if (n_) { \
READ_BITS(8U - n_); \
} \
}
#ifdef FX_FLAC_NO_CRC
/* Just alias the CRC versions of the READ macros to the read macros
themselves */
#define READ_BITS_CRC(n) READ_BITS(n)
#define READ_BITS_FAST_CRC(n) READ_BITS_FAST(n)
#define READ_BITS_DCRC(n) READ_BITS(n)
#define READ_BITS_FAST_DCRC(n) READ_BITS_FAST(n)
#define SYNC_BYTESTREAM_CRC() SYNC_BYTESTREAM()
#else /* FX_FLAC_NO_CRC */
/* Update the frame checksum while reading data */
#define READ_BITS_CRC(n) \
(tmp_ = fx_bitstream_try_read_msb_ex(&inst->bitstream, n, _fx_flac_crc16_, \
inst)); \
if (tmp_ < 0) { \
return false; /* Need more data */ \
}
#define READ_BITS_FAST_CRC(n) \
(tmp_ = fx_bitstream_read_msb_ex(&inst->bitstream, n, _fx_flac_crc16_, \
inst));
/* DCRC -> Dual CRC, update both the header and the frame checksum */
#define READ_BITS_DCRC(n) \
(tmp_ = fx_bitstream_try_read_msb_ex(&inst->bitstream, n, \
_fx_flac_double_crc_, inst)); \
if (tmp_ < 0) { \
return false; /* Need more data */ \
}
#define READ_BITS_FAST_DCRC(n) \
(tmp_ = fx_bitstream_read_msb_ex(&inst->bitstream, n, \
_fx_flac_double_crc_, inst));
#define SYNC_BYTESTREAM_CRC() \
{ \
uint8_t n_ = inst->bitstream.pos & 0x07; \
if (n_) { \
READ_BITS_CRC(8U - n_); \
} \
}
static const uint8_t fx_flac_crc8_table_[256] = {
0x00, 0x07, 0x0e, 0x09, 0x1c, 0x1b, 0x12, 0x15, 0x38, 0x3f, 0x36, 0x31,
0x24, 0x23, 0x2a, 0x2d, 0x70, 0x77, 0x7e, 0x79, 0x6c, 0x6b, 0x62, 0x65,
0x48, 0x4f, 0x46, 0x41, 0x54, 0x53, 0x5a, 0x5d, 0xe0, 0xe7, 0xee, 0xe9,
0xfc, 0xfb, 0xf2, 0xf5, 0xd8, 0xdf, 0xd6, 0xd1, 0xc4, 0xc3, 0xca, 0xcd,
0x90, 0x97, 0x9e, 0x99, 0x8c, 0x8b, 0x82, 0x85, 0xa8, 0xaf, 0xa6, 0xa1,
0xb4, 0xb3, 0xba, 0xbd, 0xc7, 0xc0, 0xc9, 0xce, 0xdb, 0xdc, 0xd5, 0xd2,
0xff, 0xf8, 0xf1, 0xf6, 0xe3, 0xe4, 0xed, 0xea, 0xb7, 0xb0, 0xb9, 0xbe,
0xab, 0xac, 0xa5, 0xa2, 0x8f, 0x88, 0x81, 0x86, 0x93, 0x94, 0x9d, 0x9a,
0x27, 0x20, 0x29, 0x2e, 0x3b, 0x3c, 0x35, 0x32, 0x1f, 0x18, 0x11, 0x16,
0x03, 0x04, 0x0d, 0x0a, 0x57, 0x50, 0x59, 0x5e, 0x4b, 0x4c, 0x45, 0x42,
0x6f, 0x68, 0x61, 0x66, 0x73, 0x74, 0x7d, 0x7a, 0x89, 0x8e, 0x87, 0x80,
0x95, 0x92, 0x9b, 0x9c, 0xb1, 0xb6, 0xbf, 0xb8, 0xad, 0xaa, 0xa3, 0xa4,
0xf9, 0xfe, 0xf7, 0xf0, 0xe5, 0xe2, 0xeb, 0xec, 0xc1, 0xc6, 0xcf, 0xc8,
0xdd, 0xda, 0xd3, 0xd4, 0x69, 0x6e, 0x67, 0x60, 0x75, 0x72, 0x7b, 0x7c,
0x51, 0x56, 0x5f, 0x58, 0x4d, 0x4a, 0x43, 0x44, 0x19, 0x1e, 0x17, 0x10,
0x05, 0x02, 0x0b, 0x0c, 0x21, 0x26, 0x2f, 0x28, 0x3d, 0x3a, 0x33, 0x34,
0x4e, 0x49, 0x40, 0x47, 0x52, 0x55, 0x5c, 0x5b, 0x76, 0x71, 0x78, 0x7f,
0x6a, 0x6d, 0x64, 0x63, 0x3e, 0x39, 0x30, 0x37, 0x22, 0x25, 0x2c, 0x2b,
0x06, 0x01, 0x08, 0x0f, 0x1a, 0x1d, 0x14, 0x13, 0xae, 0xa9, 0xa0, 0xa7,
0xb2, 0xb5, 0xbc, 0xbb, 0x96, 0x91, 0x98, 0x9f, 0x8a, 0x8d, 0x84, 0x83,
0xde, 0xd9, 0xd0, 0xd7, 0xc2, 0xc5, 0xcc, 0xcb, 0xe6, 0xe1, 0xe8, 0xef,
0xfa, 0xfd, 0xf4, 0xf3};
static const uint16_t fx_flac_crc16_table_[256] = {
0x0000, 0x8005, 0x800f, 0x000a, 0x801b, 0x001e, 0x0014, 0x8011, 0x8033,
0x0036, 0x003c, 0x8039, 0x0028, 0x802d, 0x8027, 0x0022, 0x8063, 0x0066,
0x006c, 0x8069, 0x0078, 0x807d, 0x8077, 0x0072, 0x0050, 0x8055, 0x805f,
0x005a, 0x804b, 0x004e, 0x0044, 0x8041, 0x80c3, 0x00c6, 0x00cc, 0x80c9,
0x00d8, 0x80dd, 0x80d7, 0x00d2, 0x00f0, 0x80f5, 0x80ff, 0x00fa, 0x80eb,
0x00ee, 0x00e4, 0x80e1, 0x00a0, 0x80a5, 0x80af, 0x00aa, 0x80bb, 0x00be,
0x00b4, 0x80b1, 0x8093, 0x0096, 0x009c, 0x8099, 0x0088, 0x808d, 0x8087,
0x0082, 0x8183, 0x0186, 0x018c, 0x8189, 0x0198, 0x819d, 0x8197, 0x0192,
0x01b0, 0x81b5, 0x81bf, 0x01ba, 0x81ab, 0x01ae, 0x01a4, 0x81a1, 0x01e0,
0x81e5, 0x81ef, 0x01ea, 0x81fb, 0x01fe, 0x01f4, 0x81f1, 0x81d3, 0x01d6,
0x01dc, 0x81d9, 0x01c8, 0x81cd, 0x81c7, 0x01c2, 0x0140, 0x8145, 0x814f,
0x014a, 0x815b, 0x015e, 0x0154, 0x8151, 0x8173, 0x0176, 0x017c, 0x8179,
0x0168, 0x816d, 0x8167, 0x0162, 0x8123, 0x0126, 0x012c, 0x8129, 0x0138,
0x813d, 0x8137, 0x0132, 0x0110, 0x8115, 0x811f, 0x011a, 0x810b, 0x010e,
0x0104, 0x8101, 0x8303, 0x0306, 0x030c, 0x8309, 0x0318, 0x831d, 0x8317,
0x0312, 0x0330, 0x8335, 0x833f, 0x033a, 0x832b, 0x032e, 0x0324, 0x8321,
0x0360, 0x8365, 0x836f, 0x036a, 0x837b, 0x037e, 0x0374, 0x8371, 0x8353,
0x0356, 0x035c, 0x8359, 0x0348, 0x834d, 0x8347, 0x0342, 0x03c0, 0x83c5,
0x83cf, 0x03ca, 0x83db, 0x03de, 0x03d4, 0x83d1, 0x83f3, 0x03f6, 0x03fc,
0x83f9, 0x03e8, 0x83ed, 0x83e7, 0x03e2, 0x83a3, 0x03a6, 0x03ac, 0x83a9,
0x03b8, 0x83bd, 0x83b7, 0x03b2, 0x0390, 0x8395, 0x839f, 0x039a, 0x838b,
0x038e, 0x0384, 0x8381, 0x0280, 0x8285, 0x828f, 0x028a, 0x829b, 0x029e,
0x0294, 0x8291, 0x82b3, 0x02b6, 0x02bc, 0x82b9, 0x02a8, 0x82ad, 0x82a7,
0x02a2, 0x82e3, 0x02e6, 0x02ec, 0x82e9, 0x02f8, 0x82fd, 0x82f7, 0x02f2,
0x02d0, 0x82d5, 0x82df, 0x02da, 0x82cb, 0x02ce, 0x02c4, 0x82c1, 0x8243,
0x0246, 0x024c, 0x8249, 0x0258, 0x825d, 0x8257, 0x0252, 0x0270, 0x8275,
0x827f, 0x027a, 0x826b, 0x026e, 0x0264, 0x8261, 0x0220, 0x8225, 0x822f,
0x022a, 0x823b, 0x023e, 0x0234, 0x8231, 0x8213, 0x0216, 0x021c, 0x8219,
0x0208, 0x820d, 0x8207, 0x0202};
static inline void _fx_flac_crc8_(uint8_t byte, void *data) {
fx_flac_t *inst = (fx_flac_t *)FX_ASSUME_ALIGNED(data);
inst->crc8 = fx_flac_crc8_table_[inst->crc8 ^ byte];
}
static inline void _fx_flac_crc16_(uint8_t byte, void *data) {
fx_flac_t *inst = (fx_flac_t *)FX_ASSUME_ALIGNED(data);
const uint8_t i = ((inst->crc16 >> 8U) ^ byte) & 0xFF;
inst->crc16 = fx_flac_crc16_table_[i] ^ (inst->crc16 << 8U);
}
static inline void _fx_flac_double_crc_(uint8_t byte, void *data) {
_fx_flac_crc8_(byte, data);
_fx_flac_crc16_(byte, data);
}
#endif /* FX_FLAC_NO_CRC */
static bool _fx_flac_reader_utf8_coded_int(fx_flac_t *inst, uint8_t max_n,
uint64_t *tar) {
int64_t tmp_; /* Used by the READ_BITS macro */
ENSURE_BITS(max_n * 8U);
/* Read the first byte */
uint8_t v = READ_BITS_FAST_DCRC(8U);
/* Count the number of ones in the first byte */
uint8_t n_ones = 0U;
while (v & 0x80U) {
v = v << 1U;
n_ones++;
}
/* Abort if the number of bytes to read is larger than max_n */
if (n_ones > max_n) {
inst->priv_state = FLAC_FRAME_SYNC; /* Invalid header */
return true;
}
/* Shift v back and store in var */
*tar = (v >> n_ones);
/* Read all continuation bytes */
for (uint8_t i = 1U; i < n_ones; i++) {
v = READ_BITS_FAST_DCRC(8U);
/* Abort if continuation byte doesn't start with correct sequence */
if ((v & 0xC0U) != 0x80) {
inst->priv_state = FLAC_FRAME_SYNC; /* Invalid header */
return true;
}
*tar = ((*tar) << 6U) | (v & 0x3F);
}
return true;
}
/******************************************************************************
* Private decoder state machine *
******************************************************************************/
/*
* Note: the boolean return value of these functions indicates whether they
* rand out of data -- true indicates that there is still enough data left,
* false indicates that the outer state machine should return to the user code
* to read more data. The return value does NOT indicate success/failure. This
* is what inst->state == FLAC_ERR is for.
*/
static bool _fx_flac_handle_err(fx_flac_t *inst) {
/* TODO: Add flags to fx_flac_t which control this behaviour */
/* If an error happens while searching for metadata, this is fatal. */
if (inst->state < FLAC_END_OF_METADATA) {
inst->state = FLAC_ERR;
return false;
}
/* Otherwise just try to re-synchronise with the stream by searching for the
next frame */
inst->state = FLAC_SEARCH_FRAME;
inst->priv_state = FLAC_FRAME_SYNC;
return true;
}
/**
* Statemachine used to search the beginning of the stream. This (for example)
* skips IDv3 tags prepended to the file.
*/
static bool _fx_flac_process_init(fx_flac_t *inst) {
int64_t tmp_; /* Used by the READ_BITS macro */
/* Search for the 'fLaC' sync word */
uint8_t byte = READ_BITS(8);
switch (inst->priv_state) {
case FLAC_SYNC_INIT:
if (byte == 'f') {
inst->priv_state = FLAC_SYNC_F;
}
break;
case FLAC_SYNC_F:
if (byte == 'L') {
inst->priv_state = FLAC_SYNC_L;
} else {
inst->priv_state = FLAC_SYNC_INIT;
}
break;
case FLAC_SYNC_L:
if (byte == 'a') {
inst->priv_state = FLAC_SYNC_A;
} else {
inst->priv_state = FLAC_SYNC_INIT;
}
break;
case FLAC_SYNC_A:
if (byte == 'C') {
inst->state = FLAC_IN_METADATA;
inst->priv_state = FLAC_METADATA_HEADER;
} else {
inst->priv_state = FLAC_SYNC_INIT;
}
break;
default:
return _fx_flac_handle_err(inst);
}
return true;
}
static bool _fx_flac_process_in_metadata(fx_flac_t *inst) {
int64_t tmp_; /* Used by the READ_BITS macro */
switch (inst->priv_state) {
case FLAC_METADATA_HEADER:
ENSURE_BITS(32U);
inst->metadata->is_last = READ_BITS_FAST(1U);
inst->metadata->type = (fx_flac_metadata_type_t)READ_BITS_FAST(7U);
if (inst->metadata->type == META_TYPE_INVALID) {
return _fx_flac_handle_err(inst);
}
inst->metadata->length = inst->n_bytes_rem = READ_BITS_FAST(24U);
if (inst->metadata->type == META_TYPE_STREAMINFO) {
inst->priv_state = FLAC_METADATA_SINFO;
/* The stream info header must be exactly 33 bytes long */
if (inst->metadata->length != 34U) {
return _fx_flac_handle_err(inst);
}
} else {
inst->priv_state = FLAC_METADATA_SKIP;
}
break;
case FLAC_METADATA_SINFO:
switch (inst->n_bytes_rem) {
case 34U:
inst->streaminfo->min_block_size = READ_BITS(16U);
inst->n_bytes_rem -= 2U;
break;
case 32U:
inst->streaminfo->max_block_size = READ_BITS(16U);
inst->n_bytes_rem -= 2U;
break;
case 30U:
inst->streaminfo->min_frame_size = READ_BITS(24U);
inst->n_bytes_rem -= 3U;
break;
case 27U:
inst->streaminfo->max_frame_size = READ_BITS(24U);
inst->n_bytes_rem -= 3U;
break;
case 24U:
ENSURE_BITS(28U);
inst->streaminfo->sample_rate = READ_BITS_FAST(20U);
inst->streaminfo->n_channels = 1U + READ_BITS_FAST(3U);
inst->streaminfo->sample_size = 1U + READ_BITS_FAST(5U);
inst->n_bytes_rem -= 4U;
break;
case 20U:
inst->streaminfo->n_samples = READ_BITS(36U);
inst->n_bytes_rem -= 4U;
break;
case 1U:
case 2U:
case 3U:
case 4U:
case 5U:
case 6U:
case 7U:
case 8U:
case 9U:
case 10U:
case 11U:
case 12U:
case 13U:
case 14U:
case 15U:
case 16U:
inst->streaminfo->md5_sum[16U - inst->n_bytes_rem] =
READ_BITS(8);
inst->n_bytes_rem -= 1U;
break;
case 0U:
/* Use the FLAC_END_OF_METADATA_SKIP state logic below */
inst->priv_state = FLAC_METADATA_SKIP;
break;
default:
return _fx_flac_handle_err(inst);
}
break;
case FLAC_METADATA_SKIP: {
const uint8_t n_read =
(inst->n_bytes_rem >= 7U) ? 7U : inst->n_bytes_rem;
if (n_read == 0U) { /* We read all the data for this block */
if (inst->metadata->is_last) {
/* Last metadata block, transition to the next state */
inst->state = FLAC_END_OF_METADATA;
} else {
/* End of metadata block, read the next one */
inst->priv_state = FLAC_METADATA_HEADER;
}
break;
}
READ_BITS(n_read * 8U);
inst->n_bytes_rem -= n_read;
break;
}
default:
return _fx_flac_handle_err(inst); /* Internal error */
}
return true;
}
static bool _fx_flac_process_search_frame(fx_flac_t *inst) {
int64_t tmp_; /* Used by the READ_BITS macro */
fx_flac_frame_header_t *fh = inst->frame_header;
fx_flac_streaminfo_t *si = inst->streaminfo;
switch (inst->priv_state) {
case FLAC_FRAME_SYNC:
/* Synchronise with the underlying bytestream */
SYNC_BYTESTREAM();
ENSURE_BITS(15U);
uint16_t sync_code = PEEK_BITS(15U);
if (sync_code != 0x7FFCU) {
READ_BITS(8U); /* Next byte (assume frames are byte aligned). */
return true;
} else {
inst->crc8 = 0U; /* Reset the checksums */
inst->crc16 = 0U;
inst->priv_state = FLAC_FRAME_HEADER;
READ_BITS_FAST_DCRC(15U);
}
break;
case FLAC_FRAME_HEADER:
ENSURE_BITS(17U);
/* Read the frame header bits */
fh->blocking_strategy =
(fx_flac_blocking_strategy_t)READ_BITS_FAST_DCRC(1U);
fh->block_size_enum = (fx_flac_block_size_t)READ_BITS_FAST_DCRC(4U);
fh->sample_rate_enum =
(fx_flac_sample_rate_t)READ_BITS_FAST_DCRC(4U);
fh->channel_assignment =
(fx_flac_channel_assignment_t)READ_BITS_FAST_DCRC(4U);
fh->sample_size_enum =
(fx_flac_sample_size_t)READ_BITS_FAST_DCRC(3U);
READ_BITS_FAST_DCRC(1U);
if (tmp_ != 0U || fh->channel_assignment > MID_SIDE_STEREO) {
return _fx_flac_handle_err(inst); /* Invalid header */
}
/* Copy sample rate and sample size from the streaminfo */
fh->sample_rate = si->sample_rate;
fh->sample_size = si->sample_size;
/* Decode the individual enums */
if (!_fx_flac_decode_block_size(fh->block_size_enum,
&fh->block_size) ||
!_fx_flac_decode_sample_rate(fh->sample_rate_enum,
&fh->sample_rate) ||
!_fx_flac_decode_sample_size(fh->sample_size_enum,
&fh->sample_size) ||
!_fx_flac_decode_channel_count(fh->channel_assignment,
&fh->channel_count)) {
inst->priv_state = FLAC_FRAME_SYNC; /* Got invalid value */
break;
}
inst->priv_state = FLAC_FRAME_HEADER_SYNC_INFO;
break;
case FLAC_FRAME_HEADER_SYNC_INFO:
if (!_fx_flac_reader_utf8_coded_int(
inst, (fh->blocking_strategy == BLK_VARIABLE) ? 7U : 6U,
&fh->sync_info)) {
return false;
}
inst->priv_state = FLAC_FRAME_HEADER_AUX;
break;
case FLAC_FRAME_HEADER_AUX:
ENSURE_BITS(32U);
/* Read block size/sample rate if not directly packed into the
previous header */
switch (fh->block_size_enum) {
case BLK_SIZE_READ_8BIT:
fh->block_size = 1U + READ_BITS_FAST_DCRC(8U);
break;
case BLK_SIZE_READ_16BIT:
fh->block_size = 1U + READ_BITS_FAST_DCRC(16U);
break;
default:
break;
}
switch (fh->sample_rate_enum) {
case FS_READ_8BIT_KHZ:
fh->sample_rate = 1000UL * READ_BITS_FAST_DCRC(8U);
break;
case FS_READ_16BIT_HZ:
fh->sample_rate = READ_BITS_FAST_DCRC(16U);
break;
case FS_READ_16BIT_DHZ:
fh->sample_rate = 10UL * READ_BITS_FAST_DCRC(16U);
break;
default:
break;
}
inst->priv_state = FLAC_FRAME_HEADER_CRC;
break;
case FLAC_FRAME_HEADER_CRC:
/* Read the CRC8 checksum, make sure it equals the checksum written
to the header. If not, this is not a valid header. Continue
searching. */
fh->crc8 = READ_BITS_CRC(8U);
#ifndef FX_FLAC_NO_CRC
if (fh->crc8 != inst->crc8) {
return _fx_flac_handle_err(inst);
}
#endif
/* Make sure the decode has enough space */
if ((fh->block_size > inst->max_block_size) ||
(fh->channel_count > inst->max_channels)) {
return _fx_flac_handle_err(inst);
}
/* Decode the subframes */
inst->state = FLAC_IN_FRAME;
inst->priv_state = FLAC_SUBFRAME_HEADER;
inst->chan_cur = 0U; /* Start with the first channel */
break;
default:
return _fx_flac_handle_err(inst);
}
return true;
}
static bool _fx_flac_process_in_frame(fx_flac_t *inst) {
int64_t tmp_ = 0; /* Used by the READ_BITS macro */
fx_flac_frame_header_t *fh = inst->frame_header;
fx_flac_subframe_header_t *sfh = inst->subframe_header;
int32_t *blk = inst->blkbuf[inst->chan_cur % FLAC_MAX_CHANNEL_COUNT];
const uint32_t blk_n = fh->block_size;
/* Figure out the number of bits to read for sample. This depends on the
channel assignment. */
uint8_t bps = fh->sample_size - sfh->wasted_bits;
if ((fh->channel_assignment == LEFT_SIDE_STEREO && inst->chan_cur == 1) ||
(fh->channel_assignment == RIGHT_SIDE_STEREO && inst->chan_cur == 0) ||
(fh->channel_assignment == MID_SIDE_STEREO && inst->chan_cur == 1)) {
bps++;
}
/* Discard frames with invalid bits per sample values */
if (bps == 0U || bps > 32U) {
return _fx_flac_handle_err(inst);
}
/* This flag is set to false whenever a state in the state machine
encounters and error. */
switch (inst->priv_state) {
case FLAC_SUBFRAME_HEADER: {
ENSURE_BITS(40U);
/* Reset the block write cursor, make sure initial blk sample is set
to zero for zero-order fixed LPC */
inst->blk_cur = 0U;
blk[0U] = 0U;
/* Read a zero padding bit. This must be zero. */
uint8_t padding = READ_BITS_FAST_CRC(1U);
bool valid = padding == 0U;
/* Read the frame type and order */
uint8_t type = READ_BITS_FAST_CRC(6U);
if (type & 0x20U) {
sfh->order = (type & 0x1FU) + 1U;
sfh->type = SFT_LPC;
sfh->lpc_coeffs = inst->qbuf;
inst->priv_state = FLAC_SUBFRAME_LPC;
} else if (type & 0x10U) {
return _fx_flac_handle_err(inst);
} else if (type & 0x08U) {
sfh->order = type & 0x07U;
sfh->type = SFT_FIXED;
sfh->lpc_shift = 0;
inst->priv_state = FLAC_SUBFRAME_FIXED;
valid = valid && (sfh->order <= 4U);
if (valid) {
sfh->lpc_coeffs =
(int32_t *)_fx_flac_fixed_coeffs[sfh->order];
}
} else if ((type & 0x04U) || (type & 0x02U)) {
return _fx_flac_handle_err(inst);
} else if (type & 0x01U) {
sfh->type = SFT_VERBATIM;
inst->priv_state = FLAC_SUBFRAME_VERBATIM;
} else {
sfh->type = SFT_CONSTANT;
inst->priv_state = FLAC_SUBFRAME_CONSTANT;
}
/* Read the "wasted_bits" flag */
sfh->wasted_bits = READ_BITS_FAST_CRC(1U);
if (sfh->wasted_bits) {
for (uint8_t i = 1U; i <= 30U; i++) {
const uint8_t bit = READ_BITS_FAST_CRC(1U);
if (bit == 1U) {
sfh->wasted_bits = i;
break;
}
}
valid = valid && (sfh->wasted_bits > 0U) &&
(sfh->wasted_bits < fh->sample_size);
}
/* Make sure the block is large enough for the initial samples */
valid = valid && (blk_n >= sfh->order);
if (!valid) {
_fx_flac_handle_err(inst);
}
break;
}
case FLAC_SUBFRAME_CONSTANT: {
/* Read a single sample value and spread it over the entire block
buffer for this subframe. */
blk[0U] = READ_BITS_CRC(bps);
blk[0U] = SIGN_EXTEND(blk[0U], bps);
for (uint16_t i = 1U; i < blk_n; i++) {
blk[i] = blk[0U];
}
inst->priv_state = FLAC_SUBFRAME_FINALIZE;
break;
}
case FLAC_SUBFRAME_VERBATIM:
case FLAC_SUBFRAME_FIXED:
case FLAC_SUBFRAME_LPC: {
/* Either just read up to "order" samples, or the entire block */
const uint32_t n = (sfh->type == SFT_VERBATIM) ? blk_n : sfh->order;
while (inst->blk_cur < n) {
blk[inst->blk_cur] = READ_BITS_CRC(bps);
blk[inst->blk_cur] = SIGN_EXTEND(blk[inst->blk_cur], bps);
inst->blk_cur++;
}
inst->priv_state =
(fx_flac_private_state_t)((int)inst->priv_state + 1U);
break;
}
case FLAC_SUBFRAME_LPC_HEADER: {
/* Read the coefficient precision as well as the shift value */
ENSURE_BITS(9U);
const uint8_t prec = READ_BITS_FAST_CRC(4U);
const uint8_t shift = READ_BITS_FAST_CRC(5U);
if (prec == 15U) { /* Precision of 15 bits is invalid */
return _fx_flac_handle_err(inst);
}
sfh->lpc_prec = prec + 1U;
sfh->lpc_shift = SIGN_EXTEND(shift, 5U);
if (sfh->lpc_shift < 0) {
return _fx_flac_handle_err(inst);
}
inst->coef_cur = 0U;
inst->priv_state = FLAC_SUBFRAME_LPC_COEFFS;
break;
}
case FLAC_SUBFRAME_LPC_COEFFS:
/* Read the individual predictor coefficients */
while (inst->coef_cur < sfh->order) {
uint32_t coef = READ_BITS_CRC(sfh->lpc_prec);
sfh->lpc_coeffs[inst->coef_cur] =
SIGN_EXTEND(coef, sfh->lpc_prec);
inst->coef_cur++;
}
inst->priv_state = FLAC_SUBFRAME_LPC_RESIDUAL;
break;
case FLAC_SUBFRAME_FIXED_RESIDUAL:
case FLAC_SUBFRAME_LPC_RESIDUAL: {
ENSURE_BITS(6U);
/* Read the residual encoding type and the rice partition order */
sfh->residual_method =
(fx_flac_residual_method_t)READ_BITS_FAST_CRC(2U);
if (sfh->residual_method > RES_RICE2) {
return _fx_flac_handle_err(inst);
}
sfh->rice_partition_order = READ_BITS_FAST_CRC(4U);
inst->partition_cur = 0U;
inst->priv_state = FLAC_SUBFRAME_RICE_INIT;
break;
}
case FLAC_SUBFRAME_RICE_INIT: {
/* Read the Rice parameter */
ENSURE_BITS(10U);
uint8_t n_bits = (sfh->residual_method == RES_RICE) ? 4U : 5U;
sfh->rice_parameter = READ_BITS_FAST_CRC(n_bits);
if (sfh->rice_parameter == ((1U << n_bits) - 1U)) {
sfh->rice_parameter = READ_BITS_FAST_CRC(5U);
inst->priv_state = FLAC_SUBFRAME_RICE_VERBATIM;
} else {
inst->priv_state = FLAC_SUBFRAME_RICE_UNARY;
inst->rice_unary_counter = 0U;
}
/* Compute the number of samples to read */
inst->partition_sample = blk_n >> sfh->rice_partition_order;
if (inst->partition_cur == 0U) {
/* First partition alread includes verbatim samples */
if (inst->partition_sample < sfh->order) {
return _fx_flac_handle_err(
inst); /* Number of samples is negative */
}
inst->partition_sample -= sfh->order;
}
/* Make sure we're never writing beyond the buffer for this
channel */
if ((inst->partition_sample + inst->blk_cur) > blk_n) {
return _fx_flac_handle_err(inst);
}
break;
}
case FLAC_SUBFRAME_RICE:
case FLAC_SUBFRAME_RICE_UNARY:
/* Read the individual rice samples */
while (inst->partition_sample > 0U) {
/* Read the unary part of the Rice encoded sample bit-by-bit */
if (inst->priv_state == FLAC_SUBFRAME_RICE_UNARY) {
while (true) {
const uint8_t bit = READ_BITS_CRC(1U);
if (bit) {
break;
}
inst->rice_unary_counter++;
}
}
/* If there are no more bits left below, make sure we end up
here instead of going through the unary decoder again. */
inst->priv_state = FLAC_SUBFRAME_RICE;
/* Read the remainder */
uint32_t r = 0U;
if (sfh->rice_parameter > 0U) {
r = READ_BITS_CRC(sfh->rice_parameter);
}
const uint16_t q = inst->rice_unary_counter;
const uint32_t val = (q << sfh->rice_parameter) | r;
/* Last bit determines sign */
if (val & 1) {
blk[inst->blk_cur] = -((int32_t)(val >> 1)) - 1;
} else {
blk[inst->blk_cur] = (int32_t)(val >> 1);
}
/* Read the next sample */
inst->rice_unary_counter = 0U;
inst->priv_state = FLAC_SUBFRAME_RICE_UNARY;
inst->blk_cur++;
inst->partition_sample--;
}
inst->priv_state = FLAC_SUBFRAME_RICE_FINALIZE;
break;
case FLAC_SUBFRAME_RICE_VERBATIM: {
/* Samples are encoded in verbatim in this partition */
const uint8_t bps = sfh->rice_parameter;
while (inst->partition_sample > 0U) {
blk[inst->blk_cur] = (bps == 0) ? 0U : READ_BITS_CRC(bps);
blk[inst->blk_cur] = SIGN_EXTEND(blk[inst->blk_cur], bps);
inst->blk_cur++;
inst->partition_sample--;
}
inst->priv_state = FLAC_SUBFRAME_RICE_FINALIZE;
break;
}
case FLAC_SUBFRAME_RICE_FINALIZE:
/* Go to the next partition or finalize this subframe */
inst->partition_cur++;
if (inst->partition_cur == (1U << sfh->rice_partition_order)) {
/* Decode the residual */
_fx_flac_restore_lpc_signal(blk, blk_n, sfh->lpc_coeffs,
sfh->order, sfh->lpc_shift);
inst->priv_state = FLAC_SUBFRAME_FINALIZE;
} else {
inst->priv_state = FLAC_SUBFRAME_RICE_INIT;
}
break;
case FLAC_SUBFRAME_FINALIZE: {
/* Apply the wasted bits transformation */
if (sfh->wasted_bits) {
uint8_t shift = sfh->wasted_bits;
for (uint16_t i = 0U; i < blk_n; i++) {
blk[i] = blk[i] * (1 << shift);
}
}
/* There is another subframe to read, continue! */
inst->chan_cur++; /* Go to the next channel */
if (inst->chan_cur < fh->channel_count) {
inst->priv_state = FLAC_SUBFRAME_HEADER;
break;
}
/* Synchronise with the underlying byte stream */
SYNC_BYTESTREAM_CRC();
/* Read the CRC16 sum, resync if it doesn't match our own */
uint16_t crc16 = READ_BITS(16U);
#ifndef FX_FLAC_NO_CRC
if (crc16 != inst->crc16) {
return _fx_flac_handle_err(inst);
}
#else
(void)crc16;
#endif
/* Post process side-stereo */
int32_t *c1 = inst->blkbuf[0], *c2 = inst->blkbuf[1];
switch (fh->channel_assignment) {
case LEFT_SIDE_STEREO:
_fx_flac_post_process_left_side(c1, c2, blk_n);
break;
case RIGHT_SIDE_STEREO:
_fx_flac_post_process_right_side(c1, c2, blk_n);
break;
case MID_SIDE_STEREO:
_fx_flac_post_process_mid_side(c1, c2, blk_n);
break;
default:
break;
}
/* Shift the output such that the resulting int32 stream can be
played back. */
uint8_t shift = 32U - fh->sample_size;
if (shift) {
for (uint8_t c = 0U; c < fh->channel_count; c++) {
int32_t *blk = inst->blkbuf[c];
for (uint16_t i = 0U; i < blk_n; i++) {
blk[i] = blk[i] * (1 << shift);
}
}
}
/* We're done decoding this frame! Notify the outer loop! */
inst->blk_cur = 0U; /* Reset the read cursor */
inst->chan_cur = 0U;
inst->state = FLAC_DECODED_FRAME;
break;
}
default:
inst->state = FLAC_ERR;
break;
}
return true;
}
static bool _fx_flac_process_decoded_frame(fx_flac_t *inst, int32_t *out,
uint32_t *out_len) {
/* Fetch the current stream and frame info. */
const fx_flac_frame_header_t *fh = inst->frame_header;
/* Fetch channel count and number of samples left to write */
const uint8_t cc = fh->channel_count;
uint32_t n_smpls_rem =
(fh->block_size - inst->blk_cur - 1U) * cc + (cc - inst->chan_cur);
/* Truncate to the actually available space. */
if (n_smpls_rem > *out_len) {
n_smpls_rem = *out_len;
}
/* Interlace the decoded samples in the output array */
uint32_t tar = 0U; /* Number of samples written. */
while (tar < n_smpls_rem) {
/* Write to the output buffer */
out[tar] = inst->blkbuf[inst->chan_cur][inst->blk_cur];
/* Advance the read and write cursors */
inst->chan_cur++;
if (inst->chan_cur == cc) {
inst->chan_cur = 0U;
inst->blk_cur++;
}
tar++;
}
/* Inform the caller about the number of samples written */
*out_len = tar;
/* We're done with this frame! */
if (inst->blk_cur == fh->block_size) {
inst->state = FLAC_END_OF_FRAME;
return true;
}
/* Since we're here, we need more space in the output array. */
return false;
}
/******************************************************************************
* PUBLIC API *
******************************************************************************/
uint32_t fx_flac_size(uint32_t max_block_size, uint8_t max_channels) {
/* Calculate the size of the fixed-size structures */
uint32_t size;
bool ok = _fx_flac_check_params(max_block_size, max_channels) &&
fx_mem_init_size(&size) &&
fx_mem_update_size(&size, sizeof(fx_flac_t)) &&
fx_mem_update_size(&size, sizeof(fx_flac_metadata_t)) &&
fx_mem_update_size(&size, sizeof(fx_flac_streaminfo_t)) &&
fx_mem_update_size(&size, sizeof(fx_flac_frame_header_t)) &&
fx_mem_update_size(&size, sizeof(fx_flac_subframe_header_t)) &&
fx_mem_update_size(&size, sizeof(int32_t) * 32U);
/* Calculate the size of the structures depending on the given parameters.
*/
for (uint8_t i = 0; i < max_channels; i++) {
ok = ok && fx_mem_update_size(&size, sizeof(int32_t) * max_block_size);
}
return ok ? size : 0;
}
fx_flac_t *fx_flac_init(void *mem, uint16_t max_block_size,
uint8_t max_channels) {
/* Make sure the parameters are valid. */
if (!_fx_flac_check_params(max_block_size, max_channels)) {
return NULL;
}
/* Abort if mem is NULL to allow passing malloc as a direct argument to this
code. Furthermore, store the original "mem" pointer and return it later
so the calling code is safe to pass the returned pointer to free. */
fx_flac_t *inst_unaligned = (fx_flac_t *)mem;
if (mem) {
/* Fetch the base address of the flac_t address. */
fx_flac_t *inst = (fx_flac_t *)fx_mem_align(&mem, sizeof(fx_flac_t));
/* Copy the given parameters */
inst->max_block_size = max_block_size;
inst->max_channels = max_channels;
/* Fetch the base addresses of the internal pointers. */
inst->metadata = (fx_flac_metadata_t *)fx_mem_align(
&mem, sizeof(fx_flac_metadata_t));
inst->streaminfo = (fx_flac_streaminfo_t *)fx_mem_align(
&mem, sizeof(fx_flac_streaminfo_t));
inst->frame_header = (fx_flac_frame_header_t *)fx_mem_align(
&mem, sizeof(fx_flac_frame_header_t));
inst->subframe_header = (fx_flac_subframe_header_t *)fx_mem_align(
&mem, sizeof(fx_flac_subframe_header_t));
inst->qbuf = (int32_t *)fx_mem_align(&mem, sizeof(int32_t) * 32U);
/* Compute the addresses of the per-channel buffers */
for (uint8_t i = 0; i < FLAC_MAX_CHANNEL_COUNT; i++) {
inst->blkbuf[i] = NULL;
}
for (uint8_t i = 0; i < max_channels; i++) {
inst->blkbuf[i] =
(int32_t *)fx_mem_align(&mem, sizeof(int32_t) * max_block_size);
}
/* Reset the instance, i.e. zero most/all fields. */
fx_flac_reset(inst);
}
/* Return the original pointer. */
return inst_unaligned;
}
void fx_flac_reset(fx_flac_t *inst) {
inst = (fx_flac_t *)FX_ALIGN_ADDR(inst);
/* Initialize the bitstream reader */
fx_bitstream_init(&inst->bitstream);
/* Initialize the current metadata block header */
FX_MEM_ZERO_ALIGNED(inst->metadata);
inst->metadata->type = META_TYPE_INVALID;
/* Initialize the streaminfo structure */
FX_MEM_ZERO_ALIGNED(inst->streaminfo);
/* Initialize the frame_header structure */
FX_MEM_ZERO_ALIGNED(inst->frame_header);
/* Initialize the subframe_header structure */
FX_MEM_ZERO_ALIGNED(inst->subframe_header);
/* Initialize private member variables */
inst->state = FLAC_INIT;
inst->priv_state = FLAC_SYNC_INIT;
inst->n_bytes_rem = 0U;
inst->crc8 = 0U;
inst->coef_cur = 0U;
inst->partition_cur = 0U;
inst->partition_sample = 0U;
inst->rice_unary_counter = 0U;
inst->chan_cur = 0U;
inst->blk_cur = 0U;
}
fx_flac_state_t fx_flac_get_state(const fx_flac_t *inst) {
return ((const fx_flac_t *)FX_ALIGN_ADDR(inst))->state;
}
int64_t fx_flac_get_streaminfo(fx_flac_t const *inst,
fx_flac_streaminfo_key_t key) {
inst = (fx_flac_t *)FX_ALIGN_ADDR(inst);
switch (key) {
case FLAC_KEY_MIN_BLOCK_SIZE:
return inst->streaminfo->min_block_size;
case FLAC_KEY_MAX_BLOCK_SIZE:
return inst->streaminfo->max_block_size;
case FLAC_KEY_MIN_FRAME_SIZE:
return inst->streaminfo->min_frame_size;
case FLAC_KEY_MAX_FRAME_SIZE:
return inst->streaminfo->max_frame_size;
case FLAC_KEY_SAMPLE_RATE:
return inst->streaminfo->sample_rate;
case FLAC_KEY_N_CHANNELS:
return inst->streaminfo->n_channels;
case FLAC_KEY_SAMPLE_SIZE:
return inst->streaminfo->sample_size;
case FLAC_KEY_N_SAMPLES:
return inst->streaminfo->n_samples;
case FLAC_KEY_MD5_SUM_0:
case FLAC_KEY_MD5_SUM_1:
case FLAC_KEY_MD5_SUM_2:
case FLAC_KEY_MD5_SUM_3:
case FLAC_KEY_MD5_SUM_4:
case FLAC_KEY_MD5_SUM_5:
case FLAC_KEY_MD5_SUM_6:
case FLAC_KEY_MD5_SUM_7:
case FLAC_KEY_MD5_SUM_8:
case FLAC_KEY_MD5_SUM_9:
case FLAC_KEY_MD5_SUM_A:
case FLAC_KEY_MD5_SUM_B:
case FLAC_KEY_MD5_SUM_C:
case FLAC_KEY_MD5_SUM_D:
case FLAC_KEY_MD5_SUM_E:
case FLAC_KEY_MD5_SUM_F:
return inst->streaminfo->md5_sum[key - FLAC_KEY_MD5_SUM_0];
default:
return FLAC_INVALID_METADATA_KEY;
}
}
fx_flac_state_t fx_flac_process(fx_flac_t *inst, const uint8_t *in,
uint32_t *in_len, int32_t *out,
uint32_t *out_len) {
inst = (fx_flac_t *)FX_ALIGN_ADDR(inst);
/* Set the current bytestream source to the provided input buffer */
fx_bitstream_t *bs = &inst->bitstream; /* Alias */
fx_bitstream_set_source(bs, in, *in_len);
/* Advance the statemachine */
bool done = false;
uint32_t out_len_ = 0U;
fx_flac_state_t old_state = inst->state;
while (!done) {
/* Abort once we've reached an error state. */
if (inst->state == FLAC_ERR) {
done = true;
continue; /* Panic, all hope is lost! */
}
/* Automatically return once the state transitions to a relevant state,
even if there is still data to read. */
if (old_state != inst->state) {
old_state = inst->state;
switch (inst->state) {
case FLAC_END_OF_METADATA:
case FLAC_END_OF_FRAME:
done = true; /* Good point to return to the caller */
continue;
default:
break;
}
}
/* Main state machine. Dispatch calls to the corresponding state
handlers. These will returns false in case there is no more data
to read/space to write to. */
switch (inst->state) {
case FLAC_INIT:
done = !_fx_flac_process_init(inst);
break;
case FLAC_IN_METADATA:
done = !_fx_flac_process_in_metadata(inst);
break;
case FLAC_END_OF_METADATA:
case FLAC_END_OF_FRAME:
inst->state = FLAC_SEARCH_FRAME;
inst->priv_state = FLAC_FRAME_SYNC;
break;
case FLAC_SEARCH_FRAME:
done = !_fx_flac_process_search_frame(inst);
break;
case FLAC_IN_FRAME:
done = !_fx_flac_process_in_frame(inst);
break;
case FLAC_DECODED_FRAME:
/* If no output buffers are given, just discard the data. */
if (!out || !out_len) {
inst->state = FLAC_END_OF_FRAME;
break;
}
out_len_ = *out_len;
done = !_fx_flac_process_decoded_frame(inst, out, &out_len_);
break;
default:
inst->state = FLAC_ERR; /* Internal error */
break;
}
}
/* Write the number of bytes we read from the input stream to in_len, the
caller must not provide these bytes again. Also write the number of
samples we wrote to the output buffer. */
if (out_len) {
*out_len = out_len_;
}
*in_len = bs->src - in;
/* Return the current state */
return inst->state;
}