ref: 7592cc985f084dbfab7f941100d1f09b33a43e22
dir: /common/libsndfile/src/wav_ima_adpcm.c/
/*
** Copyright (C) 1999-2001 Erik de Castro Lopo <[email protected]>
**
** This program is free software; you can redistribute it and/or modify
** it under the terms of the GNU Lesser General Public License as published by
** the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.
**
** You should have received a copy of the GNU Lesser General Public License
** along with this program; if not, write to the Free Software
** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <math.h>
#include "sndfile.h"
#include "config.h"
#include "sfendian.h"
#include "floatcast.h"
#include "common.h"
#include "wav.h"
#define RIFF_MARKER (MAKE_MARKER ('R', 'I', 'F', 'F'))
#define WAVE_MARKER (MAKE_MARKER ('W', 'A', 'V', 'E'))
#define fmt_MARKER (MAKE_MARKER ('f', 'm', 't', ' '))
#define fact_MARKER (MAKE_MARKER ('f', 'a', 'c', 't'))
#define data_MARKER (MAKE_MARKER ('d', 'a', 't', 'a'))
#define WAVE_FORMAT_IMA_ADPCM 0x0011 /* Intel Corporation */
typedef struct
{ unsigned int channels ;
unsigned int blocksize ;
unsigned int samplesperblock ;
} IMA_ADPCM_PUBLIC ;
typedef struct
{ unsigned int channels, blocksize, samplesperblock, blocks ;
int blockcount, samplecount ;
int previous [2] ;
int stepindex [2] ;
unsigned char *block ;
short *samples ;
unsigned char data [4] ; /* Dummy size */
} IMA_ADPCM_PRIVATE ;
/*============================================================================================
** Predefined IMA ADPCM data.
*/
static int ima_index_adjust [16] =
{ -1, -1, -1, -1, /* +0 - +3, decrease the step size */
2, 4, 6, 8, /* +4 - +7, increase the step size */
-1, -1, -1, -1, /* -0 - -3, decrease the step size */
2, 4, 6, 8, /* -4 - -7, increase the step size */
} ;
static int ima_step_size [89] =
{ 7, 8, 9, 10, 11, 12, 13, 14, 16, 17, 19, 21, 23, 25, 28, 31, 34, 37, 41, 45,
50, 55, 60, 66, 73, 80, 88, 97, 107, 118, 130, 143, 157, 173, 190, 209, 230,
253, 279, 307, 337, 371, 408, 449, 494, 544, 598, 658, 724, 796, 876, 963,
1060, 1166, 1282, 1411, 1552, 1707, 1878, 2066, 2272, 2499, 2749, 3024, 3327,
3660, 4026, 4428, 4871, 5358, 5894, 6484, 7132, 7845, 8630, 9493, 10442,
11487, 12635, 13899, 15289, 16818, 18500, 20350, 22385, 24623, 27086, 29794,
32767
} ;
static int ima_reader_init (SF_PRIVATE *psf, IMA_ADPCM_PUBLIC *public) ;
static int ima_writer_init (SF_PRIVATE *psf, IMA_ADPCM_PUBLIC *public) ;
static int ima_read_block (SF_PRIVATE *psf, IMA_ADPCM_PRIVATE *pima) ;
static int ima_read (SF_PRIVATE *psf, IMA_ADPCM_PRIVATE *pima, short *ptr, int len) ;
static int ima_write_block (SF_PRIVATE *psf, IMA_ADPCM_PRIVATE *pima) ;
static int ima_write (SF_PRIVATE *psf, IMA_ADPCM_PRIVATE *pima, short *ptr, int len) ;
static int ima_read_s (SF_PRIVATE *psf, short *ptr, int len) ;
static int ima_read_i (SF_PRIVATE *psf, int *ptr, int len) ;
static int ima_read_f (SF_PRIVATE *psf, float *ptr, int len) ;
static int ima_read_d (SF_PRIVATE *psf, double *ptr, int len, int normalize) ;
static int ima_write_s (SF_PRIVATE *psf, short *ptr, int len) ;
static int ima_write_i (SF_PRIVATE *psf, int *ptr, int len) ;
static int ima_write_f (SF_PRIVATE *psf, float *ptr, int len) ;
static int ima_write_d (SF_PRIVATE *psf, double *ptr, int len, int normalize) ;
static long ima_seek (SF_PRIVATE *psf, long offset, int whence) ;
static int wav_ima_close (SF_PRIVATE *psf) ;
static int wav_ima_write_header (SF_PRIVATE *psf) ;
static unsigned int wav_srate2blocksize (unsigned int srate) ;
/*============================================================================================
** IMA ADPCM Reader initialisation function.
*/
int
wav_ima_reader_init (SF_PRIVATE *psf, WAV_FMT *fmt)
{ IMA_ADPCM_PUBLIC public ;
public.blocksize = fmt->ima.blockalign ;
public.channels = fmt->ima.channels ;
public.samplesperblock = fmt->ima.samplesperblock ;
return ima_reader_init (psf, &public) ;
} /* wav_ima_reader_init */
int
wav_ima_writer_init (SF_PRIVATE *psf)
{ IMA_ADPCM_PUBLIC public ;
int error ;
public.blocksize = wav_srate2blocksize (psf->sf.samplerate) ;
public.channels = psf->sf.channels ;
public.samplesperblock = 2 * (public.blocksize - 4 * psf->sf.channels) / psf->sf.channels + 1 ;
if ((error = ima_writer_init (psf, &public)))
return error ;
wav_ima_write_header (psf) ;
psf->write_short = (func_short) ima_write_s ;
psf->write_int = (func_int) ima_write_i ;
psf->write_float = (func_float) ima_write_f ;
psf->write_double = (func_double) ima_write_d ;
psf->seek_func = (func_seek) ima_seek ;
psf->close = (func_close) wav_ima_close ;
psf->write_header = (func_wr_hdr) wav_ima_write_header ;
return 0 ;
} /* wav_ima_writer_init */
/*============================================================================================
** IMA ADPCM Read Functions.
*/
static int
ima_reader_init (SF_PRIVATE *psf, IMA_ADPCM_PUBLIC *public)
{ IMA_ADPCM_PRIVATE *pima ;
unsigned int pimasize, count ;
if (psf->mode != SF_MODE_READ)
return SFE_BAD_MODE_RW ;
pimasize = sizeof (IMA_ADPCM_PRIVATE) + public->blocksize + 3 * public->channels * public->samplesperblock ;
if (! (pima = malloc (pimasize)))
return SFE_MALLOC_FAILED ;
psf->fdata = (void*) pima ;
memset (pima, 0, pimasize) ;
pima->block = (unsigned char*) pima->data ;
pima->samples = (short*) (pima->data + public->blocksize) ;
pima->channels = public->channels ;
pima->blocksize = public->blocksize ;
pima->samplesperblock = public->samplesperblock ;
if (psf->datalength % pima->blocksize)
{ psf_log_printf (psf, "*** Warning : data chunk seems to be truncated.\n") ;
pima->blocks = psf->datalength / pima->blocksize + 1 ;
}
else
pima->blocks = psf->datalength / pima->blocksize ;
count = 2 * (pima->blocksize - 4 * pima->channels) / pima->channels + 1 ;
if (pima->samplesperblock != count)
psf_log_printf (psf, "*** Warning : samplesperblock should be %d.\n", count) ;
psf->sf.samples = pima->samplesperblock * pima->blocks ;
ima_read_block (psf, pima) ; /* Read first block. */
psf->read_short = (func_short) ima_read_s ;
psf->read_int = (func_int) ima_read_i ;
psf->read_float = (func_float) ima_read_f ;
psf->read_double = (func_double) ima_read_d ;
psf->seek_func = (func_seek) ima_seek ;
return 0 ;
} /* ima_reader_init */
static int
ima_read_block (SF_PRIVATE *psf, IMA_ADPCM_PRIVATE *pima)
{ int chan, k, current, blockindex, index, indexstart ;
short step, diff, bytecode, stepindex [2] ;
pima->blockcount ++ ;
pima->samplecount = 0 ;
if (pima->blockcount > pima->blocks)
{ memset (pima->samples, 0, pima->samplesperblock * pima->channels * sizeof (short)) ;
return 1 ;
} ;
if ((k = fread (pima->block, 1, pima->blocksize, psf->file)) != pima->blocksize)
psf_log_printf (psf, "*** Warning : short read (%d != %d).\n", k, pima->blocksize) ;
/* Read and check the block header. */
for (chan = 0 ; chan < pima->channels ; chan++)
{ current = pima->block [chan*4] | (pima->block [chan*4+1] << 8) ;
if (current & 0x8000)
current -= 0x10000 ;
stepindex [chan] = pima->block [chan*4+2] ;
if (stepindex [chan] < 0)
stepindex [chan] = 0 ;
else if (stepindex [chan] > 88)
stepindex [chan] = 88 ;
if (pima->block [chan*4+3] != 0)
psf_log_printf (psf, "IMA ADPCM synchronisation error.\n") ;
pima->samples [chan] = current ;
/* psf_log_printf (psf, "block %d : channel %d (current, index) : (%d, %d)\n",
** pima->blockcount, chan, current, stepindex [chan]) ;
*/
} ;
/* Pull apart the packed 4 bit samples and store them in their
** correct sample positions.
*/
blockindex = 4 * pima->channels ;
indexstart = pima->channels ;
while (blockindex < pima->blocksize)
{ for (chan = 0 ; chan < pima->channels ; chan++)
{ index = indexstart + chan ;
for (k = 0 ; k < 4 ; k++)
{ bytecode = pima->block [blockindex++] ;
pima->samples [index] = bytecode & 0x0F ;
index += pima->channels ;
pima->samples [index] = (bytecode >> 4) & 0x0F ;
index += pima->channels ;
} ;
} ;
indexstart += 8 * pima->channels ;
} ;
/* Decode the encoded 4 bit samples. */
for (k = pima->channels ; k < (pima->samplesperblock * pima->channels) ; k ++)
{ chan = (pima->channels > 1) ? (k % 2) : 0 ;
bytecode = pima->samples [k] & 0xF ;
step = ima_step_size [stepindex [chan]] ;
current = pima->samples [k - pima->channels] ;
diff = step >> 3 ;
if (bytecode & 1)
diff += step >> 2 ;
if (bytecode & 2)
diff += step >> 1 ;
if (bytecode & 4)
diff += step ;
if (bytecode & 8)
diff = -diff ;
current += diff ;
if (current > 32767)
current = 32767;
else if (current < -32768)
current = -32768 ;
stepindex [chan] += ima_index_adjust [bytecode] ;
if (stepindex [chan] < 0)
stepindex [chan] = 0 ;
else if (stepindex [chan] > 88)
stepindex [chan] = 88 ;
pima->samples [k] = current ;
} ;
return 1 ;
} /* ima_read_block */
static int
ima_read (SF_PRIVATE *psf, IMA_ADPCM_PRIVATE *pima, short *ptr, int len)
{ int count, total = 0, index = 0 ;
while (index < len)
{ if (pima->blockcount >= pima->blocks && pima->samplecount >= pima->samplesperblock)
{ memset (&(ptr[index]), 0, (len - index) * sizeof (short)) ;
return total ;
} ;
if (pima->samplecount >= pima->samplesperblock)
ima_read_block (psf, pima) ;
count = (pima->samplesperblock - pima->samplecount) * pima->channels ;
count = (len - index > count) ? count : len - index ;
memcpy (&(ptr[index]), &(pima->samples [pima->samplecount * pima->channels]), count * sizeof (short)) ;
index += count ;
pima->samplecount += count / pima->channels ;
total = index ;
} ;
return total ;
} /* ima_read */
static int
ima_read_s (SF_PRIVATE *psf, short *ptr, int len)
{ IMA_ADPCM_PRIVATE *pima ;
int total ;
if (! psf->fdata)
return 0 ;
pima = (IMA_ADPCM_PRIVATE*) psf->fdata ;
total = ima_read (psf, pima, ptr, len) ;
return total ;
} /* ima_read_s */
static int
ima_read_i (SF_PRIVATE *psf, int *ptr, int len)
{ IMA_ADPCM_PRIVATE *pima ;
short *sptr ;
int k, bufferlen, readcount = 0, count ;
int index = 0, total = 0 ;
if (! psf->fdata)
return 0 ;
pima = (IMA_ADPCM_PRIVATE*) psf->fdata ;
sptr = (short*) psf->buffer ;
bufferlen = ((SF_BUFFER_LEN / psf->blockwidth) * psf->blockwidth) / sizeof (short) ;
while (len > 0)
{ readcount = (len >= bufferlen) ? bufferlen : len ;
count = ima_read (psf, pima, sptr, readcount) ;
for (k = 0 ; k < readcount ; k++)
ptr [index+k] = (int) (sptr [k]) ;
index += readcount ;
total += count ;
len -= readcount ;
} ;
return total ;
} /* ima_read_i */
static int
ima_read_f (SF_PRIVATE *psf, float *ptr, int len)
{ IMA_ADPCM_PRIVATE *pima ;
short *sptr ;
int k, bufferlen, readcount = 0, count ;
int index = 0, total = 0 ;
float normfact ;
if (! psf->fdata)
return 0 ;
pima = (IMA_ADPCM_PRIVATE*) psf->fdata ;
normfact = (psf->norm_float == SF_TRUE) ? 1.0 / ((float) 0x8000) : 1.0 ;
sptr = (short*) psf->buffer ;
bufferlen = ((SF_BUFFER_LEN / psf->blockwidth) * psf->blockwidth) / sizeof (short) ;
while (len > 0)
{ readcount = (len >= bufferlen) ? bufferlen : len ;
count = ima_read (psf, pima, sptr, readcount) ;
for (k = 0 ; k < readcount ; k++)
ptr [index+k] = normfact * (float) (sptr [k]) ;
index += readcount ;
total += count ;
len -= readcount ;
} ;
return total ;
} /* ima_read_f */
static int
ima_read_d (SF_PRIVATE *psf, double *ptr, int len, int normalize)
{ IMA_ADPCM_PRIVATE *pima ;
short *sptr ;
int k, bufferlen, readcount = 0, count ;
int index = 0, total = 0 ;
double normfact ;
normfact = (normalize ? 1.0 / ((double) 0x8000) : 1.0) ;
if (! psf->fdata)
return 0 ;
pima = (IMA_ADPCM_PRIVATE*) psf->fdata ;
sptr = (short*) psf->buffer ;
bufferlen = ((SF_BUFFER_LEN / psf->blockwidth) * psf->blockwidth) / sizeof (short) ;
while (len > 0)
{ readcount = (len >= bufferlen) ? bufferlen : len ;
count = ima_read (psf, pima, sptr, readcount) ;
for (k = 0 ; k < readcount ; k++)
ptr [index+k] = normfact * (double) (sptr [k]) ;
index += readcount ;
total += count ;
len -= readcount ;
} ;
return total ;
} /* ima_read_d */
static long
ima_seek (SF_PRIVATE *psf, long offset, int whence)
{ IMA_ADPCM_PRIVATE *pima ;
int newblock, newsample ;
if (! psf->fdata)
return 0 ;
pima = (IMA_ADPCM_PRIVATE*) psf->fdata ;
if (! (psf->blockwidth && psf->datalength && psf->dataoffset))
{ psf->error = SFE_BAD_SEEK ;
return ((long) -1) ;
} ;
switch (whence)
{ case SEEK_SET :
if (offset < 0 || offset > pima->blocks * pima->samplesperblock)
{ psf->error = SFE_BAD_SEEK ;
return ((long) -1) ;
} ;
newblock = offset / pima->samplesperblock ;
newsample = offset % pima->samplesperblock ;
break ;
case SEEK_CUR :
if (psf->current + offset < 0 || psf->current + offset > pima->blocks * pima->samplesperblock)
{ psf->error = SFE_BAD_SEEK ;
return ((long) -1) ;
} ;
newblock = (psf->current + offset) / pima->samplesperblock ;
newsample = (psf->current + offset) % pima->samplesperblock ;
break ;
case SEEK_END :
if (offset > 0 || pima->samplesperblock * pima->blocks + offset < 0)
{ psf->error = SFE_BAD_SEEK ;
return ((long) -1) ;
} ;
newblock = (pima->samplesperblock * pima->blocks + offset) / pima->samplesperblock ;
newsample = (pima->samplesperblock * pima->blocks + offset) % pima->samplesperblock ;
break ;
default :
psf->error = SFE_BAD_SEEK ;
return ((long) -1) ;
} ;
if (psf->mode == SF_MODE_READ)
{ fseek (psf->file, (int) (psf->dataoffset + newblock * pima->blocksize), SEEK_SET) ;
pima->blockcount = newblock ;
ima_read_block (psf, pima) ;
pima->samplecount = newsample ;
}
else
{ /* What to do about write??? */
psf->error = SFE_BAD_SEEK ;
return ((long) -1) ;
} ;
psf->current = newblock * pima->samplesperblock + newsample ;
return psf->current ;
} /* ima_seek */
/*==========================================================================================
** IMA ADPCM Write Functions.
*/
static int
ima_writer_init (SF_PRIVATE *psf, IMA_ADPCM_PUBLIC *public)
{ IMA_ADPCM_PRIVATE *pima ;
unsigned int pimasize ;
if (psf->mode != SF_MODE_WRITE)
return SFE_BAD_MODE_RW ;
public->blocksize = wav_srate2blocksize (psf->sf.samplerate) ;
public->samplesperblock = 2 * (public->blocksize - 4 * public->channels) / public->channels + 1 ;
pimasize = sizeof (IMA_ADPCM_PRIVATE) + public->blocksize + 3 * public->channels * public->samplesperblock ;
if (! (pima = malloc (pimasize)))
return SFE_MALLOC_FAILED ;
psf->fdata = (void*) pima ;
memset (pima, 0, pimasize) ;
pima->channels = public->channels ;
pima->blocksize = public->blocksize ;
pima->samplesperblock = public->samplesperblock ;
pima->block = (unsigned char*) pima->data ;
pima->samples = (short*) (pima->data + public->blocksize) ;
pima->samplecount = 0 ;
return 0 ;
} /* ima_writer_init */
/*==========================================================================================
*/
static int
ima_write_block (SF_PRIVATE *psf, IMA_ADPCM_PRIVATE *pima)
{ int chan, k, step, diff, vpdiff, blockindex, index, indexstart ;
short bytecode, mask ;
/* Write the block header. */
for (chan = 0 ; chan < pima->channels ; chan++)
{ pima->block [chan*4] = pima->samples [chan] & 0xFF ;
pima->block [chan*4+1] = (pima->samples [chan] >> 8) & 0xFF ;
pima->block [chan*4+2] = pima->stepindex [chan] ;
pima->block [chan*4+3] = 0 ;
} ;
pima->previous [0] = pima->samples [0] ;
pima->previous [1] = pima->samples [1] ;
/* Encode the samples as 4 bit. */
for (k = pima->channels ; k < (pima->samplesperblock * pima->channels) ; k ++)
{ chan = (pima->channels > 1) ? (k % 2) : 0 ;
diff = pima->samples [k] - pima->previous [chan] ;
bytecode = 0 ;
step = ima_step_size [pima->stepindex [chan]] ;
vpdiff = step >> 3 ;
if (diff < 0)
{ bytecode = 8 ;
diff = -diff ;
} ;
mask = 4 ;
while (mask)
{ if (diff >= step)
{ bytecode |= mask ;
diff -= step ;
vpdiff += step ;
} ;
step >>= 1 ;
mask >>= 1 ;
} ;
if (bytecode & 8)
pima->previous [chan] -= vpdiff ;
else
pima->previous [chan] += vpdiff ;
if (pima->previous [chan] > 32767)
pima->previous [chan] = 32767;
else if (pima->previous [chan] < -32768)
pima->previous [chan] = -32768;
pima->stepindex [chan] += ima_index_adjust [bytecode] ;
if (pima->stepindex [chan] < 0)
pima->stepindex [chan] = 0 ;
else if (pima->stepindex [chan] > 88)
pima->stepindex [chan] = 88 ;
pima->samples [k] = bytecode ;
} ;
/* Pack the 4 bit encoded samples. */
blockindex = 4 * pima->channels ;
indexstart = pima->channels ;
while (blockindex < pima->blocksize)
{ for (chan = 0 ; chan < pima->channels ; chan++)
{ index = indexstart + chan ;
for (k = 0 ; k < 4 ; k++)
{ pima->block [blockindex] = pima->samples [index] & 0x0F ;
index += pima->channels ;
pima->block [blockindex] |= (pima->samples [index] << 4) & 0xF0 ;
index += pima->channels ;
blockindex ++ ;
} ;
} ;
indexstart += 8 * pima->channels ;
} ;
/* Write the block to disk. */
if ((k = fwrite (pima->block, 1, pima->blocksize, psf->file)) != pima->blocksize)
psf_log_printf (psf, "*** Warning : short write (%d != %d).\n", k, pima->blocksize) ;
memset (pima->samples, 0, pima->samplesperblock * sizeof (short)) ;
pima->samplecount = 0 ;
return 1 ;
} /* ima_write_block */
static int
ima_write (SF_PRIVATE *psf, IMA_ADPCM_PRIVATE *pima, short *ptr, int len)
{ int count, total = 0, index = 0 ;
while (index < len)
{ count = (pima->samplesperblock - pima->samplecount) * pima->channels ;
if (count > len - index)
count = len - index ;
memcpy (&(pima->samples [pima->samplecount * pima->channels]), &(ptr [index]), count * sizeof (short)) ;
index += count ;
pima->samplecount += count / pima->channels ;
total = index ;
if (pima->samplecount >= pima->samplesperblock)
ima_write_block (psf, pima) ;
} ;
return total ;
} /* ima_write */
static int
ima_write_s (SF_PRIVATE *psf, short *ptr, int len)
{ IMA_ADPCM_PRIVATE *pima ;
int total ;
if (! psf->fdata)
return 0 ;
pima = (IMA_ADPCM_PRIVATE*) psf->fdata ;
total = ima_write (psf, pima, ptr, len) ;
return total ;
} /* ima_write_s */
static int
ima_write_i (SF_PRIVATE *psf, int *ptr, int len)
{ IMA_ADPCM_PRIVATE *pima ;
short *sptr ;
int k, bufferlen, writecount = 0, count ;
int index = 0, total = 0 ;
if (! psf->fdata)
return 0 ;
pima = (IMA_ADPCM_PRIVATE*) psf->fdata ;
sptr = (short*) psf->buffer ;
bufferlen = ((SF_BUFFER_LEN / psf->blockwidth) * psf->blockwidth) / sizeof (short) ;
while (len > 0)
{ writecount = (len >= bufferlen) ? bufferlen : len ;
for (k = 0 ; k < writecount ; k++)
sptr [k] = (short) ptr [index+k] ;
count = ima_write (psf, pima, sptr, writecount) ;
index += writecount ;
total += count ;
len -= writecount ;
} ;
return total ;
} /* ima_write_i */
static int
ima_write_f (SF_PRIVATE *psf, float *ptr, int len)
{ IMA_ADPCM_PRIVATE *pima ;
short *sptr ;
int k, bufferlen, writecount = 0, count ;
int index = 0, total = 0 ;
float normfact ;
if (! psf->fdata)
return 0 ;
pima = (IMA_ADPCM_PRIVATE*) psf->fdata ;
normfact = (psf->norm_float == SF_TRUE) ? ((float) 0x8000) : 1.0 ;
sptr = (short*) psf->buffer ;
bufferlen = ((SF_BUFFER_LEN / psf->blockwidth) * psf->blockwidth) / sizeof (short) ;
while (len > 0)
{ writecount = (len >= bufferlen) ? bufferlen : len ;
for (k = 0 ; k < writecount ; k++)
sptr [k] = FLOAT_TO_SHORT (normfact * ptr [index+k]) ;
count = ima_write (psf, pima, sptr, writecount) ;
index += writecount ;
total += count ;
len -= writecount ;
} ;
return total ;
} /* ima_write_f */
static int
ima_write_d (SF_PRIVATE *psf, double *ptr, int len, int normalize)
{ IMA_ADPCM_PRIVATE *pima ;
short *sptr ;
int k, bufferlen, writecount = 0, count ;
int index = 0, total = 0 ;
double normfact ;
normfact = (normalize ? ((double) 0x8000) : 1.0) ;
if (! psf->fdata)
return 0 ;
pima = (IMA_ADPCM_PRIVATE*) psf->fdata ;
sptr = (short*) psf->buffer ;
bufferlen = ((SF_BUFFER_LEN / psf->blockwidth) * psf->blockwidth) / sizeof (short) ;
while (len > 0)
{ writecount = (len >= bufferlen) ? bufferlen : len ;
for (k = 0 ; k < writecount ; k++)
sptr [k] = DOUBLE_TO_SHORT (normfact * ptr [index+k]) ;
count = ima_write (psf, pima, sptr, writecount) ;
index += writecount ;
total += count ;
len -= writecount ;
} ;
return total ;
} /* ima_write_d */
static int
wav_ima_write_header (SF_PRIVATE *psf)
{ int fmt_size, blockalign, samplesperblock, bytespersec ;
blockalign = wav_srate2blocksize (psf->sf.samplerate) ;
samplesperblock = 2 * (blockalign - 4 * psf->sf.channels) / psf->sf.channels + 1 ;
bytespersec = (psf->sf.samplerate * blockalign) / samplesperblock ;
/* Reset the current header length to zero. */
psf->header [0] = 0 ;
psf->headindex = 0 ;
fseek (psf->file, 0, SEEK_SET) ;
/* RIFF marker, length, WAVE and 'fmt ' markers. */
psf_binheader_writef (psf, "mlmm", RIFF_MARKER, psf->filelength - 8, WAVE_MARKER, fmt_MARKER) ;
/* fmt chunk. */
fmt_size = 2 + 2 + 4 + 4 + 2 + 2 + 2 + 2 ;
/* fmt : size, WAV format type, channels. */
psf_binheader_writef (psf, "lww", fmt_size, WAVE_FORMAT_IMA_ADPCM, psf->sf.channels) ;
/* fmt : samplerate, bytespersec. */
psf_binheader_writef (psf, "ll", psf->sf.samplerate, bytespersec) ;
/* fmt : blockalign, bitwidth, extrabytes, samplesperblock. */
psf_binheader_writef (psf, "wwww", blockalign, 4, 2, samplesperblock) ;
/* Fact chunk. */
psf_binheader_writef (psf, "mll", fact_MARKER, sizeof (int), psf->sf.samples) ;
/* DATA chunk. */
psf_binheader_writef (psf, "ml", data_MARKER, psf->datalength) ;
fwrite (psf->header, psf->headindex, 1, psf->file) ;
psf->dataoffset = psf->headindex ;
psf->datalength = (psf->sf.samples / samplesperblock) * samplesperblock ;
if (psf->sf.samples % samplesperblock)
psf->datalength += samplesperblock ;
return 0 ;
} /* wav_ima_write_header */
static int
wav_ima_close (SF_PRIVATE *psf)
{ IMA_ADPCM_PRIVATE *pima ;
if (! psf->fdata)
return 0 ;
pima = (IMA_ADPCM_PRIVATE*) psf->fdata ;
if (psf->mode == SF_MODE_WRITE)
{ /* If a block has been partially assembled, write it out
** as the final block.
*/
if (pima->samplecount && pima->samplecount < pima->samplesperblock)
ima_write_block (psf, pima) ;
/* Now we know for certain the length of the file we can
** re-write the header.
*/
fseek (psf->file, 0, SEEK_END) ;
psf->filelength = ftell (psf->file) ;
psf->sf.samples = pima->samplesperblock * pima->blockcount ;
psf->datalength = psf->filelength - psf->dataoffset ;
wav_ima_write_header (psf) ;
} ;
if (psf->fdata)
free (psf->fdata) ;
psf->fdata = NULL ;
return 0 ;
} /* wav_ima_close */
static unsigned
int wav_srate2blocksize (unsigned int srate)
{ if (srate < 12000)
return 256 ;
if (srate < 23000)
return 512 ;
return 1024 ;
} /* wav_srate2blocksize */