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/* license:BSD-3-Clause
* copyright-holders:Aaron Giles
***************************************************************************
flac.c
FLAC compression wrappers
***************************************************************************/
#include <assert.h>
#include <string.h>
#include <libchdr/flac.h>
#define DR_FLAC_IMPLEMENTATION
#include <dr_libs/dr_flac.h>
/***************************************************************************
* FLAC DECODER
***************************************************************************
*/
static size_t flac_decoder_read_callback(void *userdata, void *buffer, size_t bytes);
static drflac_bool32 flac_decoder_seek_callback(void *userdata, int offset, drflac_seek_origin origin);
static void flac_decoder_metadata_callback(void *userdata, drflac_metadata *metadata);
static void flac_decoder_write_callback(void *userdata, void *buffer, size_t len);
/* getters (valid after reset) */
static uint32_t sample_rate(flac_decoder *decoder) { return decoder->sample_rate; }
static uint8_t channels(flac_decoder *decoder) { return decoder->channels; }
static uint8_t bits_per_sample(flac_decoder *decoder) { return decoder->bits_per_sample; }
/*-------------------------------------------------
* flac_decoder - constructor
*-------------------------------------------------
*/
int flac_decoder_init(flac_decoder *decoder)
{
decoder->decoder = NULL;
decoder->sample_rate = 0;
decoder->channels = 0;
decoder->bits_per_sample = 0;
decoder->compressed_offset = 0;
decoder->compressed_start = NULL;
decoder->compressed_length = 0;
decoder->compressed2_start = NULL;
decoder->compressed2_length = 0;
decoder->uncompressed_offset = 0;
decoder->uncompressed_length = 0;
decoder->uncompressed_swap = 0;
return 0;
}
/*-------------------------------------------------
* flac_decoder - destructor
*-------------------------------------------------
*/
void flac_decoder_free(flac_decoder* decoder)
{
if ((decoder != NULL) && (decoder->decoder != NULL))
drflac_close(decoder->decoder);
decoder->decoder = NULL;
}
/*-------------------------------------------------
* reset - reset state with the original
* parameters
*-------------------------------------------------
*/
static int flac_decoder_internal_reset(flac_decoder* decoder)
{
decoder->compressed_offset = 0;
flac_decoder_free(decoder);
decoder->decoder = drflac_open_with_metadata(
flac_decoder_read_callback, flac_decoder_seek_callback,
flac_decoder_metadata_callback, decoder, NULL);
return (decoder->decoder != NULL);
}
/*-------------------------------------------------
* reset - reset state with new memory parameters
* and a custom-generated header
*-------------------------------------------------
*/
int flac_decoder_reset(flac_decoder* decoder, uint32_t sample_rate, uint8_t num_channels, uint32_t block_size, const void *buffer, uint32_t length)
{
/* modify the template header with our parameters */
static const uint8_t s_header_template[0x2a] =
{
0x66, 0x4C, 0x61, 0x43, /* +00: 'fLaC' stream header */
0x80, /* +04: metadata block type 0 (STREAMINFO), */
/* flagged as last block */
0x00, 0x00, 0x22, /* +05: metadata block length = 0x22 */
0x00, 0x00, /* +08: minimum block size */
0x00, 0x00, /* +0A: maximum block size */
0x00, 0x00, 0x00, /* +0C: minimum frame size (0 == unknown) */
0x00, 0x00, 0x00, /* +0F: maximum frame size (0 == unknown) */
0x0A, 0xC4, 0x42, 0xF0, 0x00, 0x00, 0x00, 0x00, /* +12: sample rate (0x0ac44 == 44100), */
/* numchannels (2), sample bits (16), */
/* samples in stream (0 == unknown) */
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* +1A: MD5 signature (0 == none) */
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 /* +2A: start of stream data */
};
memcpy(decoder->custom_header, s_header_template, sizeof(s_header_template));
decoder->custom_header[0x08] = decoder->custom_header[0x0a] = (block_size*num_channels) >> 8;
decoder->custom_header[0x09] = decoder->custom_header[0x0b] = (block_size*num_channels) & 0xff;
decoder->custom_header[0x12] = sample_rate >> 12;
decoder->custom_header[0x13] = sample_rate >> 4;
decoder->custom_header[0x14] = (sample_rate << 4) | ((num_channels - 1) << 1);
/* configure the header ahead of the provided buffer */
decoder->compressed_start = (const uint8_t *)(decoder->custom_header);
decoder->compressed_length = sizeof(decoder->custom_header);
decoder->compressed2_start = (const uint8_t *)(buffer);
decoder->compressed2_length = length;
return flac_decoder_internal_reset(decoder);
}
/*-------------------------------------------------
* decode_interleaved - decode to an interleaved
* sound stream
*-------------------------------------------------
*/
int flac_decoder_decode_interleaved(flac_decoder* decoder, int16_t *samples, uint32_t num_samples, int swap_endian)
{
/* configure the uncompressed buffer */
memset(decoder->uncompressed_start, 0, sizeof(decoder->uncompressed_start));
decoder->uncompressed_start[0] = samples;
decoder->uncompressed_offset = 0;
decoder->uncompressed_length = num_samples;
decoder->uncompressed_swap = swap_endian;
#define BUFFER 2352 /* bytes per CD audio sector */
int16_t buffer[BUFFER];
uint32_t buf_samples = BUFFER / channels(decoder);
/* loop until we get everything we want */
while (decoder->uncompressed_offset < decoder->uncompressed_length) {
uint32_t frames = (num_samples < buf_samples ? num_samples : buf_samples);
if (!drflac_read_pcm_frames_s16(decoder->decoder, frames, buffer))
return 0;
flac_decoder_write_callback(decoder, buffer, frames*sizeof(*buffer)*channels(decoder));
num_samples -= frames;
}
return 1;
}
/*-------------------------------------------------
* finish - finish up the decode
*-------------------------------------------------
*/
uint32_t flac_decoder_finish(flac_decoder* decoder)
{
/* get the final decoding position and move forward */
drflac *flac = decoder->decoder;
uint64_t position = decoder->compressed_offset;
/* ugh... there's no function to obtain bytes used in drflac :-/ */
position -= DRFLAC_CACHE_L2_LINES_REMAINING(&flac->bs) * sizeof(drflac_cache_t);
position -= DRFLAC_CACHE_L1_BITS_REMAINING(&flac->bs) / 8;
position -= flac->bs.unalignedByteCount;
/* adjust position if we provided the header */
if (position == 0)
return 0;
if (decoder->compressed_start == (const uint8_t *)(decoder->custom_header))
position -= decoder->compressed_length;
flac_decoder_free(decoder);
return position;
}
/*-------------------------------------------------
* read_callback - handle reads from the input
* stream
*-------------------------------------------------
*/
#define MIN(x, y) ((x) < (y) ? (x) : (y))
static size_t flac_decoder_read_callback(void *userdata, void *buffer, size_t bytes)
{
flac_decoder* decoder = (flac_decoder*)userdata;
uint8_t *dst = buffer;
/* copy from primary buffer first */
uint32_t outputpos = 0;
if (outputpos < bytes && decoder->compressed_offset < decoder->compressed_length)
{
uint32_t bytes_to_copy = MIN(bytes - outputpos, decoder->compressed_length - decoder->compressed_offset);
memcpy(&dst[outputpos], decoder->compressed_start + decoder->compressed_offset, bytes_to_copy);
outputpos += bytes_to_copy;
decoder->compressed_offset += bytes_to_copy;
}
/* once we're out of that, copy from the secondary buffer */
if (outputpos < bytes && decoder->compressed_offset < decoder->compressed_length + decoder->compressed2_length)
{
uint32_t bytes_to_copy = MIN(bytes - outputpos, decoder->compressed2_length - (decoder->compressed_offset - decoder->compressed_length));
memcpy(&dst[outputpos], decoder->compressed2_start + decoder->compressed_offset - decoder->compressed_length, bytes_to_copy);
outputpos += bytes_to_copy;
decoder->compressed_offset += bytes_to_copy;
}
return outputpos;
}
/*-------------------------------------------------
* metadata_callback - handle STREAMINFO metadata
*-------------------------------------------------
*/
static void flac_decoder_metadata_callback(void *userdata, drflac_metadata *metadata)
{
flac_decoder *decoder = userdata;
/* ignore all but STREAMINFO metadata */
if (metadata->type != DRFLAC_METADATA_BLOCK_TYPE_STREAMINFO)
return;
/* parse out the data we care about */
decoder->sample_rate = metadata->data.streaminfo.sampleRate;
decoder->bits_per_sample = metadata->data.streaminfo.bitsPerSample;
decoder->channels = metadata->data.streaminfo.channels;
}
/*-------------------------------------------------
* write_callback - handle writes to the output
* stream
*-------------------------------------------------
*/
static void flac_decoder_write_callback(void *userdata, void *buffer, size_t bytes)
{
int sampnum, chan;
int shift, blocksize;
flac_decoder * decoder = (flac_decoder *)userdata;
int16_t *sampbuf = (int16_t *)buffer;
int sampch = channels(decoder);
uint32_t offset = decoder->uncompressed_offset;
uint16_t usample;
/* interleaved case */
shift = decoder->uncompressed_swap ? 8 : 0;
blocksize = bytes / (sampch * sizeof(sampbuf[0]));
if (decoder->uncompressed_start[1] == NULL)
{
int16_t *dest = decoder->uncompressed_start[0] + offset * sampch;
for (sampnum = 0; sampnum < blocksize && offset < decoder->uncompressed_length; sampnum++, offset++)
for (chan = 0; chan < sampch; chan++) {
usample = (uint16_t)*sampbuf++;
*dest++ = (int16_t)((usample << shift) | (usample >> shift));
}
}
/* non-interleaved case */
else
{
for (sampnum = 0; sampnum < blocksize && offset < decoder->uncompressed_length; sampnum++, offset++)
for (chan = 0; chan < sampch; chan++) {
usample = (uint16_t)*sampbuf++;
if (decoder->uncompressed_start[chan] != NULL)
decoder->uncompressed_start[chan][offset] = (int16_t) ((usample << shift) | (usample >> shift));
}
}
decoder->uncompressed_offset = offset;
}
/*-------------------------------------------------
* seek_callback - handle seeks on the output
* stream
*-------------------------------------------------
*/
static drflac_bool32 flac_decoder_seek_callback(void *userdata, int offset, drflac_seek_origin origin)
{
flac_decoder * decoder = (flac_decoder *)userdata;
uint32_t length = decoder->compressed_length + decoder->compressed2_length;
if (origin == drflac_seek_origin_start) {
uint32_t pos = offset;
if (pos <= length) {
decoder->compressed_offset = pos;
return 1;
}
} else if (origin == drflac_seek_origin_current) {
uint32_t pos = decoder->compressed_offset + offset;
if (pos <= length) {
decoder->compressed_offset = pos;
return 1;
}
}
return 0;
}
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