/*

SDL_mixer: An audio mixer library based on the SDL library

Copyright (C) 1997-2009 Sam Lantinga

This library is free software; you can redistribute it and/or

modify it under the terms of the GNU Library General Public

License as published by the Free Software Foundation; either

version 2 of the License, or (at your option) any later version.

This library 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

Library General Public License for more details.

You should have received a copy of the GNU Library General Public

License along with this library; if not, write to the Free

Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

This is the source needed to decode a FLAC into a waveform.

~ Austen Dicken (admin@cvpcs.org).

*/

#ifdef FLAC_MUSIC

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include "SDL_mutex.h"

#include "SDL_endian.h"

#include "SDL_timer.h"

#include "SDL_mixer.h"

#include "dynamic_flac.h"

#include "load_flac.h"

#include <FLAC/stream_decoder.h>

typedef struct {

SDL_RWops* sdl_src;

SDL_AudioSpec* sdl_spec;

Uint8** sdl_audio_buf;

Uint32* sdl_audio_len;

int sdl_audio_read;

FLAC__uint64 flac_total_samples;

unsigned flac_bps;

} FLAC_SDL_Data;

static FLAC__StreamDecoderReadStatus flac_read_load_cb(

void *client_data) {

// make sure there is something to be reading

if (*bytes > 0) {

FLAC_SDL_Data *data = (FLAC_SDL_Data *)client_data;

*bytes = SDL_RWread (data->sdl_src, buffer, sizeof (FLAC__byte),

*bytes);

if(*bytes < 0) { // error in read

return FLAC__STREAM_DECODER_READ_STATUS_ABORT;

}

else if(*bytes == 0) { // no data was read (EOF)

return FLAC__STREAM_DECODER_READ_STATUS_END_OF_STREAM;

}

else { // data was read, continue

return FLAC__STREAM_DECODER_READ_STATUS_CONTINUE;

}

}

else {

return FLAC__STREAM_DECODER_READ_STATUS_ABORT;

}

}

static FLAC__StreamDecoderSeekStatus flac_seek_load_cb(

const FLAC__StreamDecoder *decoder,

FLAC__uint64 absolute_byte_offset,

void *client_data) {

FLAC_SDL_Data *data = (FLAC_SDL_Data *)client_data;

if (SDL_RWseek (data->sdl_src, absolute_byte_offset, SEEK_SET) < 0) {

return FLAC__STREAM_DECODER_SEEK_STATUS_ERROR;

}

else {

return FLAC__STREAM_DECODER_SEEK_STATUS_OK;

}

}

static FLAC__StreamDecoderTellStatus flac_tell_load_cb(

const FLAC__StreamDecoder *decoder,

FLAC__uint64 *absolute_byte_offset,

void *client_data) {

FLAC_SDL_Data *data = (FLAC_SDL_Data *)client_data;

int pos = SDL_RWtell (data->sdl_src);

if (pos < 0) {

return FLAC__STREAM_DECODER_TELL_STATUS_ERROR;

}

else {

*absolute_byte_offset = (FLAC__uint64)pos;

return FLAC__STREAM_DECODER_TELL_STATUS_OK;

}

}

static FLAC__StreamDecoderLengthStatus flac_length_load_cb(

const FLAC__StreamDecoder *decoder,

FLAC__uint64 *stream_length,

void *client_data) {

FLAC_SDL_Data *data = (FLAC_SDL_Data *)client_data;

int pos = SDL_RWtell (data->sdl_src);

int length = SDL_RWseek (data->sdl_src, 0, SEEK_END);

if (SDL_RWseek (data->sdl_src, pos, SEEK_SET) != pos || length < 0) {

/* there was an error attempting to return the stream to the original

* position, or the length was invalid. */

return FLAC__STREAM_DECODER_LENGTH_STATUS_ERROR;

}

else {

*stream_length = (FLAC__uint64)length;

return FLAC__STREAM_DECODER_LENGTH_STATUS_OK;

}

}

static FLAC__bool flac_eof_load_cb(const FLAC__StreamDecoder *decoder,

void *client_data) {

FLAC_SDL_Data *data = (FLAC_SDL_Data *)client_data;

int pos = SDL_RWtell (data->sdl_src);

int end = SDL_RWseek (data->sdl_src, 0, SEEK_END);

// was the original position equal to the end (a.k.a. the seek didn't move)?

if (pos == end) {

// must be EOF

return true;

}

else {

// not EOF, return to the original position

SDL_RWseek (data->sdl_src, pos, SEEK_SET);

return false;

}

}

static FLAC__StreamDecoderWriteStatus flac_write_load_cb(

void *client_data) {

FLAC_SDL_Data *data = (FLAC_SDL_Data *)client_data;

size_t i;

if (data->flac_total_samples == 0) {

SDL_SetError ("Given FLAC file does not specify its sample count.");

return FLAC__STREAM_DECODER_WRITE_STATUS_ABORT;

}

if (data->sdl_spec->channels != 2 || data->flac_bps != 16) {

SDL_SetError ("Current FLAC support is only for 16 bit Stereo files.");

return FLAC__STREAM_DECODER_WRITE_STATUS_ABORT;

}

// check if it is the first audio frame so we can initialize the output

// buffer

if (frame->header.number.sample_number == 0) {

*(data->sdl_audio_len) = data->sdl_spec->size;

data->sdl_audio_read = 0;

*(data->sdl_audio_buf) = malloc (*(data->sdl_audio_len));

if (*(data->sdl_audio_buf) == NULL) {

SDL_SetError

("Unable to allocate memory to store the FLAC stream.");

return FLAC__STREAM_DECODER_WRITE_STATUS_ABORT;

}

}

Uint8 *buf = *(data->sdl_audio_buf);

for (i = 0; i < frame->header.blocksize; i++) {

FLAC__int16 i16;

FLAC__uint16 ui16;

i16 = (FLAC__int16)buffer[0][i];

ui16 = (FLAC__uint16)i16;

*(buf + (data->sdl_audio_read++)) = (char)(ui16);

*(buf + (data->sdl_audio_read++)) = (char)(ui16 >> 8);

i16 = (FLAC__int16)buffer[1][i];

ui16 = (FLAC__uint16)i16;

*(buf + (data->sdl_audio_read++)) = (char)(ui16);

*(buf + (data->sdl_audio_read++)) = (char)(ui16 >> 8);

}

return FLAC__STREAM_DECODER_WRITE_STATUS_CONTINUE;

}

static void flac_metadata_load_cb(

const FLAC__StreamDecoder *decoder,

const FLAC__StreamMetadata *metadata,

void *client_data) {

FLAC_SDL_Data *data = (FLAC_SDL_Data *)client_data;

FLAC__uint64 total_samples;

unsigned bps;

if (metadata->type == FLAC__METADATA_TYPE_STREAMINFO) {

// save the metadata right now for use later on

*(data->sdl_audio_buf) = NULL;

*(data->sdl_audio_len) = 0;

memset (data->sdl_spec, '\0', sizeof (SDL_AudioSpec));

data->sdl_spec->format = AUDIO_S16;

data->sdl_spec->freq = (int)(metadata->data.stream_info.sample_rate);

data->sdl_spec->channels = (Uint8)(metadata->data.stream_info.channels);

data->sdl_spec->samples = 8192; /* buffer size */

total_samples = metadata->data.stream_info.total_samples;

bps = metadata->data.stream_info.bits_per_sample;

data->sdl_spec->size = total_samples * data->sdl_spec->channels *

(bps / 8);

data->flac_total_samples = total_samples;

data->flac_bps = bps;

}

}

static void flac_error_load_cb(

const FLAC__StreamDecoder *decoder,

FLAC__StreamDecoderErrorStatus status,

void *client_data) {

// print an SDL error based on the error status

switch (status) {

case FLAC__STREAM_DECODER_ERROR_STATUS_LOST_SYNC:

SDL_SetError ("Error processing the FLAC file [LOST_SYNC].");

break;

case FLAC__STREAM_DECODER_ERROR_STATUS_BAD_HEADER:

SDL_SetError ("Error processing the FLAC file [BAD_HEADER].");

break;

case FLAC__STREAM_DECODER_ERROR_STATUS_FRAME_CRC_MISMATCH:

SDL_SetError ("Error processing the FLAC file [CRC_MISMATCH].");

break;

case FLAC__STREAM_DECODER_ERROR_STATUS_UNPARSEABLE_STREAM:

SDL_SetError ("Error processing the FLAC file [UNPARSEABLE].");

break;

default:

SDL_SetError ("Error processing the FLAC file [UNKNOWN].");

break;

}

}

/* don't call this directly; use Mix_LoadWAV_RW() for now. */

SDL_AudioSpec *Mix_LoadFLAC_RW (SDL_RWops *src, int freesrc,

SDL_AudioSpec *spec, Uint8 **audio_buf, Uint32 *audio_len) {

FLAC__StreamDecoder *decoder = 0;

FLAC__StreamDecoderInitStatus init_status;

int was_error = 1;

int was_init = 0;

Uint32 samplesize;

// create the client data passing information

FLAC_SDL_Data* client_data;

client_data = (FLAC_SDL_Data *)malloc (sizeof (FLAC_SDL_Data));

if ((!src) || (!audio_buf) || (!audio_len)) /* sanity checks. */

goto done;

if (Mix_InitFLAC() < 0)

goto done;

if ((decoder = flac.FLAC__stream_decoder_new ()) == NULL) {

SDL_SetError ("Unable to allocate FLAC decoder.");

goto done;

}

init_status = flac.FLAC__stream_decoder_init_stream (decoder,

flac_read_load_cb, flac_seek_load_cb,

flac_tell_load_cb, flac_length_load_cb,

flac_eof_load_cb, flac_write_load_cb,

flac_metadata_load_cb, flac_error_load_cb,

client_data);

if (init_status != FLAC__STREAM_DECODER_INIT_STATUS_OK) {

SDL_SetError ("Unable to initialize FLAC stream decoder.");

goto done;

}

was_init = 1;

client_data->sdl_src = src;

client_data->sdl_spec = spec;

client_data->sdl_audio_buf = audio_buf;

client_data->sdl_audio_len = audio_len;

if (!flac.FLAC__stream_decoder_process_until_end_of_stream (decoder)) {

SDL_SetError ("Unable to process FLAC file.");

goto done;

}

was_error = 0;

/* Don't return a buffer that isn't a multiple of samplesize */

samplesize = ((spec->format & 0xFF) / 8) * spec->channels;

*audio_len &= ~(samplesize - 1);

done:

if(was_init && decoder) {

flac.FLAC__stream_decoder_finish (decoder);

}

if(decoder) {

flac.FLAC__stream_decoder_delete (decoder);

}

if (src) {

if (freesrc)

SDL_RWclose (src);

else

SDL_RWseek (src, 0, SEEK_SET);

}

if (was_error)

spec = NULL;

Mix_QuitFLAC ();

return spec;

}

#endif // FLAC_MUSIC