/*

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 Creative Labs VOC file into a

waveform. It's pretty straightforward once you get going. The only

externally-callable function is Mix_LoadVOC_RW(), which is meant to

act as identically to SDL_LoadWAV_RW() as possible.

This file by Ryan C. Gordon (icculus@icculus.org).

Heavily borrowed from sox v12.17.1's voc.c.

(http://www.freshmeat.net/projects/sox/)

*/

/* $Id$ */

#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 "load_voc.h"

/* Private data for VOC file */

typedef struct vocstuff {

} vs_t;

/* Size field */

/* SJB: note that the 1st 3 are sometimes used as sizeof(type) */

#define ST_SIZE_BYTE 1

#define ST_SIZE_8BIT 1

#define ST_SIZE_WORD 2

#define ST_SIZE_16BIT 2

#define ST_SIZE_DWORD 4

#define ST_SIZE_32BIT 4

#define ST_SIZE_FLOAT 5

#define ST_SIZE_DOUBLE 6

#define ST_SIZE_IEEE 7 /* IEEE 80-bit floats. */

/* Style field */

#define ST_ENCODING_UNSIGNED 1 /* unsigned linear: Sound Blaster */

#define ST_ENCODING_SIGN2 2 /* signed linear 2's comp: Mac */

#define ST_ENCODING_ULAW 3 /* U-law signed logs: US telephony, SPARC */

#define ST_ENCODING_ALAW 4 /* A-law signed logs: non-US telephony */

#define ST_ENCODING_ADPCM 5 /* Compressed PCM */

#define ST_ENCODING_IMA_ADPCM 6 /* Compressed PCM */

#define ST_ENCODING_GSM 7 /* GSM 6.10 33-byte frame lossy compression */

#define VOC_TERM 0

#define VOC_DATA 1

#define VOC_CONT 2

#define VOC_SILENCE 3

#define VOC_MARKER 4

#define VOC_TEXT 5

#define VOC_LOOP 6

#define VOC_LOOPEND 7

#define VOC_EXTENDED 8

#define VOC_DATA_16 9

static int voc_check_header(SDL_RWops *src)

{

/* VOC magic header */

Uint8 signature[20]; /* "Creative Voice File\032" */

Uint16 datablockofs;

SDL_RWseek(src, 0, SEEK_SET);

if (SDL_RWread(src, signature, sizeof (signature), 1) != 1)

return(0);

if (memcmp(signature, "Creative Voice File\032", sizeof (signature)) != 0) {

SDL_SetError("Unrecognized file type (not VOC)");

return(0);

}

/* get the offset where the first datablock is located */

if (SDL_RWread(src, &datablockofs, sizeof (Uint16), 1) != 1)

return(0);

datablockofs = SDL_SwapLE16(datablockofs);

if (SDL_RWseek(src, datablockofs, SEEK_SET) != datablockofs)

return(0);

return(1); /* success! */

} /* voc_check_header */

/* Read next block header, save info, leave position at start of data */

static int voc_get_block(SDL_RWops *src, vs_t *v, SDL_AudioSpec *spec)

{

Uint8 bits24[3];

Uint8 uc, block;

Uint32 sblen;

Uint16 new_rate_short;

Uint32 new_rate_long;

Uint8 trash[6];

Uint16 period;

unsigned int i;

v->silent = 0;

while (v->rest == 0)

{

if (SDL_RWread(src, &block, sizeof (block), 1) != 1)

return 1; /* assume that's the end of the file. */

if (block == VOC_TERM)

return 1;

if (SDL_RWread(src, bits24, sizeof (bits24), 1) != 1)

return 1; /* assume that's the end of the file. */

/* Size is an 24-bit value. Ugh. */

sblen = ( (bits24[0]) | (bits24[1] << 8) | (bits24[2] << 16) );

switch(block)

{

case VOC_DATA:

if (SDL_RWread(src, &uc, sizeof (uc), 1) != 1)

return 0;

/* When DATA block preceeded by an EXTENDED */

/* block, the DATA blocks rate value is invalid */

if (!v->has_extended)

{

if (uc == 0)

{

SDL_SetError("VOC Sample rate is zero?");

return 0;

}

if ((v->rate != -1) && (uc != v->rate))

{

SDL_SetError("VOC sample rate codes differ");

return 0;

}

v->rate = uc;

spec->freq = (Uint16)(1000000.0/(256 - v->rate));

v->channels = 1;

}

if (SDL_RWread(src, &uc, sizeof (uc), 1) != 1)

return 0;

if (uc != 0)

{

SDL_SetError("VOC decoder only interprets 8-bit data");

return 0;

}

v->has_extended = 0;

v->rest = sblen - 2;

v->size = ST_SIZE_BYTE;

return 1;

case VOC_DATA_16:

if (SDL_RWread(src, &new_rate_long, sizeof (new_rate_long), 1) != 1)

return 0;

new_rate_long = SDL_SwapLE32(new_rate_long);

if (new_rate_long == 0)

{

SDL_SetError("VOC Sample rate is zero?");

return 0;

}

if ((v->rate != -1) && (new_rate_long != v->rate))

{

SDL_SetError("VOC sample rate codes differ");

return 0;

}

v->rate = new_rate_long;

spec->freq = new_rate_long;

if (SDL_RWread(src, &uc, sizeof (uc), 1) != 1)

return 0;

switch (uc)

{

case 8: v->size = ST_SIZE_BYTE; break;

case 16: v->size = ST_SIZE_WORD; break;

default:

SDL_SetError("VOC with unknown data size");

return 0;

}

if (SDL_RWread(src, &v->channels, sizeof (Uint8), 1) != 1)

return 0;

if (SDL_RWread(src, trash, sizeof (Uint8), 6) != 6)

return 0;

v->rest = sblen - 12;

return 1;

case VOC_CONT:

v->rest = sblen;

return 1;

case VOC_SILENCE:

if (SDL_RWread(src, &period, sizeof (period), 1) != 1)

return 0;

period = SDL_SwapLE16(period);

if (SDL_RWread(src, &uc, sizeof (uc), 1) != 1)

return 0;

if (uc == 0)

{

SDL_SetError("VOC silence sample rate is zero");

return 0;

}

/*

* Some silence-packed files have gratuitously

* different sample rate codes in silence.

* Adjust period.

*/

if ((v->rate != -1) && (uc != v->rate))

period = (Uint16)((period * (256 - uc))/(256 - v->rate));

else

v->rate = uc;

v->rest = period;

v->silent = 1;

return 1;

case VOC_LOOP:

case VOC_LOOPEND:

for(i = 0; i < sblen; i++) /* skip repeat loops. */

{

if (SDL_RWread(src, trash, sizeof (Uint8), 1) != 1)

return 0;

}

break;

case VOC_EXTENDED:

/* An Extended block is followed by a data block */

/* Set this byte so we know to use the rate */

/* value from the extended block and not the */

/* data block. */

v->has_extended = 1;

if (SDL_RWread(src, &new_rate_short, sizeof (new_rate_short), 1) != 1)

return 0;

new_rate_short = SDL_SwapLE16(new_rate_short);

if (new_rate_short == 0)

{

SDL_SetError("VOC sample rate is zero");

return 0;

}

if ((v->rate != -1) && (new_rate_short != v->rate))

{

SDL_SetError("VOC sample rate codes differ");

return 0;

}

v->rate = new_rate_short;

if (SDL_RWread(src, &uc, sizeof (uc), 1) != 1)

return 0;

if (uc != 0)

{

SDL_SetError("VOC decoder only interprets 8-bit data");

return 0;

}

if (SDL_RWread(src, &uc, sizeof (uc), 1) != 1)

return 0;

if (uc)

spec->channels = 2; /* Stereo */

/* Needed number of channels before finishing

compute for rate */

spec->freq = (256000000L/(65536L - v->rate))/spec->channels;

/* An extended block must be followed by a data */

/* block to be valid so loop back to top so it */

/* can be grabed. */

continue;

case VOC_MARKER:

if (SDL_RWread(src, trash, sizeof (Uint8), 2) != 2)

return 0;

/* Falling! Falling! */

default: /* text block or other krapola. */

for(i = 0; i < sblen; i++)

{

if (SDL_RWread(src, &trash, sizeof (Uint8), 1) != 1)

return 0;

}

if (block == VOC_TEXT)

continue; /* get next block */

}

}

return 1;

}

static int voc_read(SDL_RWops *src, vs_t *v, Uint8 *buf, SDL_AudioSpec *spec)

{

int done = 0;

Uint8 silence = 0x80;

if (v->rest == 0)

{

if (!voc_get_block(src, v, spec))

return 0;

}

if (v->rest == 0)

return 0;

if (v->silent)

{

if (v->size == ST_SIZE_WORD)

silence = 0x00;

/* Fill in silence */

memset(buf, silence, v->rest);

done = v->rest;

v->rest = 0;

}

else

{

done = SDL_RWread(src, buf, 1, v->rest);

v->rest -= done;

if (v->size == ST_SIZE_WORD)

{

#if (SDL_BYTEORDER == SDL_BIG_ENDIAN)

Uint16 *samples = (Uint16 *)buf;

for (; v->rest > 0; v->rest -= 2)

{

*samples = SDL_SwapLE16(*samples);

samples++;

}

#endif

done >>= 1;

}

}

return done;

} /* voc_read */

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

SDL_AudioSpec *Mix_LoadVOC_RW (SDL_RWops *src, int freesrc,

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

{

vs_t v;

int was_error = 1;

int samplesize;

Uint8 *fillptr;

void *ptr;

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

goto done;

if ( !voc_check_header(src) )

goto done;

v.rate = -1;

v.rest = 0;

v.has_extended = 0;

*audio_buf = NULL;

*audio_len = 0;

memset(spec, '\0', sizeof (SDL_AudioSpec));

if (!voc_get_block(src, &v, spec))

goto done;

if (v.rate == -1)

{

SDL_SetError("VOC data had no sound!");

goto done;

}

spec->format = ((v.size == ST_SIZE_WORD) ? AUDIO_S16 : AUDIO_U8);

if (spec->channels == 0)

spec->channels = v.channels;

*audio_len = v.rest;

*audio_buf = malloc(v.rest);

if (*audio_buf == NULL)

goto done;

fillptr = *audio_buf;

while (voc_read(src, &v, fillptr, spec) > 0)

{

if (!voc_get_block(src, &v, spec))

goto done;

*audio_len += v.rest;

ptr = realloc(*audio_buf, *audio_len);

if (ptr == NULL)

{

free(*audio_buf);

*audio_buf = NULL;

*audio_len = 0;

goto done;

}

*audio_buf = ptr;

fillptr = ((Uint8 *) ptr) + (*audio_len - v.rest);

}

spec->samples = (Uint16)(*audio_len / v.size);

was_error = 0; /* success, baby! */

/* 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 (src)

{

if (freesrc)

SDL_RWclose(src);

else

SDL_RWseek(src, 0, SEEK_SET);

}

if ( was_error )

spec = NULL;

return(spec);

} /* Mix_LoadVOC_RW */

/* end of load_voc.c ... */