This software is provided 'as-is', without any express or implied

warranty. In no event will the authors be held liable for any damages

arising from the use of this software.

Permission is granted to anyone to use this software for any purpose,

including commercial applications, and to alter it and redistribute it

freely, subject to the following restrictions:

1. The origin of this software must not be misrepresented; you must not

claim that you wrote the original software. If you use this software

in a product, an acknowledgment in the product documentation would be

appreciated but is not required.

2. Altered source versions must be plainly marked as such, and must not be

misrepresented as being the original software.

3. This notice may not be removed or altered from any source distribution.

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.

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

*/

#include "SDL_mixer.h"

/* Private data for VOC file */

typedef struct vocstuff {

Uint32 rest; /* bytes remaining in current block */

Uint32 rate; /* rate code (byte) of this chunk */

int silent; /* sound or silence? */

Uint32 srate; /* rate code (byte) of silence */

Uint32 blockseek; /* start of current output block */

Uint32 samples; /* number of samples output */

Uint32 size; /* word length of data */

Uint8 channels; /* number of sound channels */

int has_extended; /* Has an extended block been read? */

} vs_t;

#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

{

/* VOC magic header */

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

Uint16 datablockofs;

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

return(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);

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;

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. */

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 (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;

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->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))

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. */

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)

{

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 */

done = v->rest;

v->rest = 0;

}

else

{

v->rest -= done;

if (v->size == ST_SIZE_WORD)

{

#if (SDL_BYTEORDER == SDL_BIG_ENDIAN)

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

{

*samples = SDL_SwapLE16(*samples);

samples++;

}

#endif

}

}

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;

goto done;

goto done;

v.rate = -1;

v.rest = 0;

*audio_buf = NULL;

*audio_len = 0;

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;

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;

if (ptr == NULL)

{

*audio_buf = NULL;

*audio_len = 0;

goto done;

}

*audio_buf = ptr;

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

}

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 (freesrc && src) {

SDL_RWclose(src);

}

return(spec);

} /* Mix_LoadVOC_RW */

/* vi: set ts=4 sw=4 expandtab: */