ref: 46d58fc082a8537f9de79342cd7d7d24974c984d
dir: /common/libsndfile/src/dwvw.c/
/*
** Copyright (C) 2002 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.
*/
/*===========================================================================
** Delta Word Variable Width
**
** This decoder and encoder were implemented using information found in this
** document : http://home.swbell.net/rubywand/R011SNDFMTS.TXT
**
** According to the document, the algorithm "was invented 1991 by Magnus
** Lidstrom and is copyright 1993 by NuEdge Development".
*/
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include "sndfile.h"
#include "config.h"
#include "sfendian.h"
#include "float_cast.h"
#include "common.h"
typedef struct
{ int filedes ;
int dwm_maxsize, bit_width, max_delta, span ;
int samplecount ;
int bit_count, bits, last_delta_width, last_sample ;
struct
{ int index, end ;
unsigned char buffer [256] ;
} b ;
} DWVW_PRIVATE ;
/*============================================================================================
*/
static sf_count_t dwvw_read_s (SF_PRIVATE *psf, short *ptr, sf_count_t len) ;
static sf_count_t dwvw_read_i (SF_PRIVATE *psf, int *ptr, sf_count_t len) ;
static sf_count_t dwvw_read_f (SF_PRIVATE *psf, float *ptr, sf_count_t len) ;
static sf_count_t dwvw_read_d (SF_PRIVATE *psf, double *ptr, sf_count_t len) ;
static sf_count_t dwvw_write_s (SF_PRIVATE *psf, short *ptr, sf_count_t len) ;
static sf_count_t dwvw_write_i (SF_PRIVATE *psf, int *ptr, sf_count_t len) ;
static sf_count_t dwvw_write_f (SF_PRIVATE *psf, float *ptr, sf_count_t len) ;
static sf_count_t dwvw_write_d (SF_PRIVATE *psf, double *ptr, sf_count_t len) ;
static sf_count_t dwvw_seek (SF_PRIVATE *psf, int mode, sf_count_t offset) ;
static int dwvw_close (SF_PRIVATE *psf) ;
static sf_count_t dwvw_decode_data (DWVW_PRIVATE *pdwvw, int *ptr, sf_count_t len) ;
static int dwvw_decode_load_bits (DWVW_PRIVATE *pdwvw, int bit_count) ;
static sf_count_t dwvw_encode_data (DWVW_PRIVATE *pdwvw, int *ptr, sf_count_t len) ;
static void dwvw_encode_store_bits (DWVW_PRIVATE *pdwvw, int data, int new_bits) ;
static void dwvw_read_reset (DWVW_PRIVATE *pdwvw) ;
/*============================================================================================
** DWVW initialisation function.
*/
int
dwvw_init (SF_PRIVATE *psf, int bitwidth)
{ DWVW_PRIVATE *pdwvw ;
if (bitwidth > 24)
return SFE_DWVW_BAD_BITWIDTH ;
if (psf->mode == SFM_RDWR)
return SFE_BAD_MODE_RW ;
if (! (pdwvw = malloc (sizeof (DWVW_PRIVATE))))
return SFE_MALLOC_FAILED ;
psf->fdata = (void*) pdwvw ;
memset (pdwvw, 0, sizeof (DWVW_PRIVATE)) ;
pdwvw->filedes = psf->filedes ;
pdwvw->bit_width = bitwidth ;
pdwvw->dwm_maxsize = bitwidth / 2 ;
pdwvw->max_delta = 1 << (bitwidth - 1) ;
pdwvw->span = 1 << bitwidth ;
dwvw_read_reset (pdwvw) ;
if (psf->mode == SFM_READ)
{ psf->read_short = dwvw_read_s ;
psf->read_int = dwvw_read_i ;
psf->read_float = dwvw_read_f ;
psf->read_double = dwvw_read_d ;
} ;
if (psf->mode == SFM_WRITE)
{ psf->write_short = dwvw_write_s ;
psf->write_int = dwvw_write_i ;
psf->write_float = dwvw_write_f ;
psf->write_double = dwvw_write_d ;
} ;
psf->new_seek = dwvw_seek ;
psf->close = dwvw_close ;
/* FIXME : This s bogus. */
if (psf->sf.samples <= 0)
psf->sf.samples = (psf->blockwidth) ? SF_MAX_COUNT / psf->blockwidth : SF_MAX_COUNT ;
psf->datalength = SF_MAX_COUNT ;
/* EMXIF : This s bogus. */
return 0 ;
} /* dwvw_init */
/*--------------------------------------------------------------------------------------------
*/
static int
dwvw_close (SF_PRIVATE *psf)
{ DWVW_PRIVATE *pdwvw ;
if (! psf->fdata)
return 0 ;
pdwvw = (DWVW_PRIVATE*) psf->fdata ;
if (psf->mode == SFM_WRITE)
{ static int last_values [8] = { 0, 0, 0, 0, 0, 0, 0, 0 } ;
/* Write 8 zero samples to fully flush output. */
dwvw_encode_data (pdwvw, last_values, 8) ;
/* Write the last buffer worth of data to disk. */
psf_fwrite (pdwvw->b.buffer, 1, pdwvw->b.index, pdwvw->filedes) ;
/* Now we know for certain the length of the file we can re-write
** correct values for the FORM, COMM and SSND chunks.
*/
psf_fseek (psf->filedes, 0, SEEK_END) ;
psf->filelength = psf_ftell (psf->filedes) ;
psf_fseek (psf->filedes, 0, SEEK_SET) ;
psf->datalength = psf->filelength - psf->dataoffset ;
psf->sf.samples = pdwvw->samplecount ;
if (psf->write_header)
psf->write_header (psf) ;
} ;
if (psf->fdata)
free (psf->fdata) ;
psf->fdata = NULL ;
return 0 ;
} /* dwvw_close */
static sf_count_t
dwvw_seek (SF_PRIVATE *psf, int mode, sf_count_t offset)
{ DWVW_PRIVATE *pdwvw ;
mode = mode ;
if (! psf->fdata)
{ psf->error = SFE_INTERNAL ;
return ((sf_count_t) -1) ;
} ;
pdwvw = (DWVW_PRIVATE*) psf->fdata ;
if (offset == 0)
{ psf_fseek (psf->filedes, psf->dataoffset, SEEK_SET) ;
dwvw_read_reset (pdwvw) ;
return 0 ;
} ;
psf->error = SFE_BAD_SEEK ;
return ((sf_count_t) -1) ;
} /* dwvw_seek */
/*==============================================================================
*/
static sf_count_t
dwvw_read_s (SF_PRIVATE *psf, short *ptr, sf_count_t len)
{ DWVW_PRIVATE *pdwvw ;
int *iptr ;
int k, bufferlen, readcount = 0, count ;
int index = 0, total = 0 ;
if (! psf->fdata)
return 0 ;
pdwvw = (DWVW_PRIVATE*) psf->fdata ;
iptr = (int*) psf->buffer ;
bufferlen = SF_BUFFER_LEN / sizeof (int) ;
while (len > 0)
{ readcount = (len >= bufferlen) ? bufferlen : len ;
count = dwvw_decode_data (pdwvw, iptr, readcount) ;
for (k = 0 ; k < readcount ; k++)
ptr [index + k] = iptr [k] >> 16 ;
index += readcount ;
total += count ;
len -= readcount ;
} ;
return total ;
} /* dwvw_read_s */
static sf_count_t
dwvw_read_i (SF_PRIVATE *psf, int *ptr, sf_count_t len)
{ DWVW_PRIVATE *pdwvw ;
sf_count_t total ;
if (! psf->fdata)
return 0 ;
pdwvw = (DWVW_PRIVATE*) psf->fdata ;
total = dwvw_decode_data (pdwvw, ptr, len) ;
return total ;
} /* dwvw_read_i */
static sf_count_t
dwvw_read_f (SF_PRIVATE *psf, float *ptr, sf_count_t len)
{ DWVW_PRIVATE *pdwvw ;
int *iptr ;
int k, bufferlen, readcount = 0, count ;
int index = 0, total = 0 ;
float normfact ;
if (! psf->fdata)
return 0 ;
pdwvw = (DWVW_PRIVATE*) psf->fdata ;
normfact = (psf->norm_float == SF_TRUE) ? 1.0 / ((float) 0x80000000) : 1.0 ;
iptr = (int*) psf->buffer ;
bufferlen = SF_BUFFER_LEN / sizeof (int) ;
while (len > 0)
{ readcount = (len >= bufferlen) ? bufferlen : len ;
count = dwvw_decode_data (pdwvw, iptr, readcount) ;
for (k = 0 ; k < readcount ; k++)
ptr [index + k] = normfact * (float) (iptr [k]) ;
index += readcount ;
total += count ;
len -= readcount ;
} ;
return total ;
} /* dwvw_read_f */
static sf_count_t
dwvw_read_d (SF_PRIVATE *psf, double *ptr, sf_count_t len)
{ DWVW_PRIVATE *pdwvw ;
int *iptr ;
int k, bufferlen, readcount = 0, count ;
int index = 0, total = 0 ;
double normfact ;
if (! psf->fdata)
return 0 ;
pdwvw = (DWVW_PRIVATE*) psf->fdata ;
normfact = (psf->norm_double == SF_TRUE) ? 1.0 / ((double) 0x80000000) : 1.0 ;
iptr = (int*) psf->buffer ;
bufferlen = SF_BUFFER_LEN / sizeof (int) ;
while (len > 0)
{ readcount = (len >= bufferlen) ? bufferlen : len ;
count = dwvw_decode_data (pdwvw, iptr, readcount) ;
for (k = 0 ; k < readcount ; k++)
ptr [index + k] = normfact * (double) (iptr [k]) ;
index += readcount ;
total += count ;
len -= readcount ;
} ;
return total ;
} /* dwvw_read_d */
static sf_count_t
dwvw_decode_data (DWVW_PRIVATE *pdwvw, int *ptr, sf_count_t len)
{ sf_count_t count ;
int delta_width_modifier, delta_width, delta_negative, delta, sample ;
/* Restore state from last decode call. */
delta_width = pdwvw->last_delta_width ;
sample = pdwvw->last_sample ;
for (count = 0 ; count < len ; count++)
{ /* If bit_count parameter is zero get the delta_width_modifier. */
delta_width_modifier = dwvw_decode_load_bits (pdwvw, -1) ;
/* Check for end of input bit stream. Break loop if end. */
if (delta_width_modifier < 0)
break ;
if (delta_width_modifier && dwvw_decode_load_bits (pdwvw, 1))
delta_width_modifier = - delta_width_modifier ;
/* Calculate the current word width. */
delta_width = (delta_width + delta_width_modifier + pdwvw->bit_width) % pdwvw->bit_width ;
/* Load the delta. */
delta = 0 ;
if (delta_width)
{ delta = dwvw_decode_load_bits (pdwvw, delta_width - 1) | (1 << (delta_width - 1)) ;
delta_negative = dwvw_decode_load_bits (pdwvw, 1) ;
if (delta == pdwvw->max_delta - 1)
delta += dwvw_decode_load_bits (pdwvw, 1) ;
if (delta_negative)
delta = -delta ;
} ;
/* Calculate the sample */
sample += delta ;
if (sample >= pdwvw->max_delta)
sample -= pdwvw->span ;
else if (sample < - pdwvw->max_delta)
sample += pdwvw->span ;
/* Store the sample justifying to the most significant bit. */
ptr [count] = sample << (32 - pdwvw->bit_width) ;
if (pdwvw->b.end == 0 && pdwvw->bit_count == 0)
break ;
} ;
pdwvw->last_delta_width = delta_width ;
pdwvw->last_sample = sample ;
pdwvw->samplecount += count ;
return count ;
} /* dwvw_decode_data */
static int
dwvw_decode_load_bits (DWVW_PRIVATE *pdwvw, int bit_count)
{ int output = 0, get_dwm = SF_FALSE ;
/*
** Depending on the value of parameter bit_count, either get the
** required number of bits (ie bit_count > 0) or the
** delta_width_modifier (otherwise).
*/
if (bit_count < 0)
{ get_dwm = SF_TRUE ;
/* modify bit_count to ensure we have enought bits for finding dwm. */
bit_count = pdwvw->dwm_maxsize ;
} ;
/* Load bits in bit reseviour. */
while (pdwvw->bit_count < bit_count)
{ if (pdwvw->b.index >= pdwvw->b.end)
{ pdwvw->b.end = psf_fread (pdwvw->b.buffer, 1, sizeof (pdwvw->b.buffer), pdwvw->filedes) ;
pdwvw->b.index = 0 ;
} ;
/* Check for end of input stream. */
if (bit_count < 8 && pdwvw->b.end == 0)
return -1 ;
pdwvw->bits = (pdwvw->bits << 8) ;
if (pdwvw->b.index < pdwvw->b.end)
{ pdwvw->bits |= pdwvw->b.buffer [pdwvw->b.index] ;
pdwvw->b.index ++ ;
} ;
pdwvw->bit_count += 8 ;
} ;
/* If asked to get bits do so. */
if (! get_dwm)
{ output = (pdwvw->bits >> (pdwvw->bit_count - bit_count)) & ((1 << bit_count) - 1) ;
pdwvw->bit_count -= bit_count ;
return output ;
} ;
/* Otherwise must have been asked to get delta_width_modifier. */
while (output < (pdwvw->dwm_maxsize))
{ pdwvw->bit_count -= 1 ;
if (pdwvw->bits & (1 << pdwvw->bit_count))
break ;
output += 1 ;
} ;
return output ;
} /* dwvw_decode_load_bits */
static void
dwvw_read_reset (DWVW_PRIVATE *pdwvw)
{ pdwvw->samplecount = 0 ;
pdwvw->b.index = 0 ;
pdwvw->b.end = 0 ;
pdwvw->bit_count = 0 ;
pdwvw->bits = 0 ;
pdwvw->last_delta_width = 0 ;
pdwvw->last_sample = 0 ;
} /* dwvw_read_reset */
static void
dwvw_encode_store_bits (DWVW_PRIVATE *pdwvw, int data, int new_bits)
{ int byte ;
/* Shift the bits into the resevoir. */
pdwvw->bits = (pdwvw->bits << new_bits) | (data & ((1 << new_bits) - 1)) ;
pdwvw->bit_count += new_bits ;
/* Transfer bit to buffer. */
while (pdwvw->bit_count >= 8)
{ byte = pdwvw->bits >> (pdwvw->bit_count - 8) ;
pdwvw->bit_count -= 8 ;
pdwvw->b.buffer [pdwvw->b.index] = byte & 0xFF ;
pdwvw->b.index ++ ;
} ;
if (pdwvw->b.index > SIGNED_SIZEOF (pdwvw->b.buffer) - 4)
{ psf_fwrite (pdwvw->b.buffer, 1, pdwvw->b.index, pdwvw->filedes) ;
pdwvw->b.index = 0 ;
} ;
return ;
} /* dwvw_encode_store_bits */
#if 0
/* Debigging routine. */
static void
dump_bits (DWVW_PRIVATE *pdwvw)
{ int k, mask ;
for (k = 0 ; k < 10 && k < pdwvw->b.index ; k++)
{ mask = 0x80 ;
while (mask)
{ putchar (mask & pdwvw->b.buffer [k] ? '1' : '0') ;
mask >>= 1 ;
} ;
putchar (' ') ;
}
for (k = pdwvw->bit_count - 1 ; k >= 0 ; k --)
putchar (pdwvw->bits & (1 << k) ? '1' : '0') ;
putchar ('\n') ;
} /* dump_bits */
#endif
#define HIGHEST_BIT(x,count) \
{ int y = x ; \
(count) = 0 ; \
while (y) \
{ (count) ++ ; \
y >>= 1 ; \
} ; \
} ;
static sf_count_t
dwvw_encode_data (DWVW_PRIVATE *pdwvw, int *ptr, sf_count_t len)
{ sf_count_t count ;
int delta_width_modifier, delta, delta_negative, delta_width, extra_bit ;
for (count = 0 ; count < len ; count++)
{ delta = (ptr [count] >> (32 - pdwvw->bit_width)) - pdwvw->last_sample ;
/* Calculate extra_bit if needed. */
extra_bit = -1 ;
delta_negative = 0 ;
if (delta < -pdwvw->max_delta)
delta = pdwvw->max_delta + (delta % pdwvw->max_delta) ;
else if (delta == -pdwvw->max_delta)
{ extra_bit = 1 ;
delta_negative = 1 ;
delta = pdwvw->max_delta - 1 ;
}
else if (delta > pdwvw->max_delta)
{ delta_negative = 1 ;
delta = pdwvw->span - delta ;
delta = abs (delta) ;
}
else if (delta == pdwvw->max_delta)
{ extra_bit = 1 ;
delta = pdwvw->max_delta - 1 ;
}
else if (delta < 0)
{ delta_negative = 1 ;
delta = abs (delta) ;
} ;
if (delta == pdwvw->max_delta - 1 && extra_bit == -1)
extra_bit = 0 ;
/* Find width in bits of delta */
HIGHEST_BIT (delta, delta_width) ;
/* Calculate the delta_width_modifier */
delta_width_modifier = (delta_width - pdwvw->last_delta_width) % pdwvw->bit_width ;
if (delta_width_modifier > pdwvw->dwm_maxsize)
delta_width_modifier -= pdwvw->bit_width ;
if (delta_width_modifier < -pdwvw->dwm_maxsize)
delta_width_modifier += pdwvw->bit_width ;
/* Write delta_width_modifier zeros, followed by terminating '1'. */
dwvw_encode_store_bits (pdwvw, 0, abs (delta_width_modifier)) ;
if (abs (delta_width_modifier) != pdwvw->dwm_maxsize)
dwvw_encode_store_bits (pdwvw, 1, 1) ;
/* Write delta_width_modifier sign. */
if (delta_width_modifier < 0)
dwvw_encode_store_bits (pdwvw, 1, 1) ;
if (delta_width_modifier > 0)
dwvw_encode_store_bits (pdwvw, 0, 1) ;
/* Write delta and delta sign bit. */
if (delta_width)
{ dwvw_encode_store_bits (pdwvw, delta, abs (delta_width) - 1) ;
dwvw_encode_store_bits (pdwvw, (delta_negative ? 1 : 0), 1) ;
} ;
/* Write extra bit!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! */
if (extra_bit >= 0)
dwvw_encode_store_bits (pdwvw, extra_bit, 1) ;
pdwvw->last_sample = ptr [count] >> (32 - pdwvw->bit_width) ;
pdwvw->last_delta_width = delta_width ;
} ;
pdwvw->samplecount += count ;
return count ;
} /* dwvw_encode_data */
static sf_count_t
dwvw_write_s (SF_PRIVATE *psf, short *ptr, sf_count_t len)
{ DWVW_PRIVATE *pdwvw ;
int *iptr ;
int k, bufferlen, writecount = 0, count ;
int index = 0, total = 0 ;
if (! psf->fdata)
return 0 ;
pdwvw = (DWVW_PRIVATE*) psf->fdata ;
iptr = (int*) psf->buffer ;
bufferlen = SF_BUFFER_LEN / sizeof (int) ;
while (len > 0)
{ writecount = (len >= bufferlen) ? bufferlen : len ;
for (k = 0 ; k < writecount ; k++)
iptr [k] = ptr [index + k] << 16 ;
count = dwvw_encode_data (pdwvw, iptr, writecount) ;
index += writecount ;
total += count ;
len -= writecount ;
} ;
return total ;
} /* dwvw_write_s */
static sf_count_t
dwvw_write_i (SF_PRIVATE *psf, int *ptr, sf_count_t len)
{ DWVW_PRIVATE *pdwvw ;
sf_count_t total ;
if (! psf->fdata)
return 0 ;
pdwvw = (DWVW_PRIVATE*) psf->fdata ;
total = dwvw_encode_data (pdwvw, ptr, len) ;
return total ;
} /* dwvw_write_i */
static sf_count_t
dwvw_write_f (SF_PRIVATE *psf, float *ptr, sf_count_t len)
{ DWVW_PRIVATE *pdwvw ;
int *iptr ;
int k, bufferlen, writecount = 0, count ;
int index = 0, total = 0 ;
float normfact ;
if (! psf->fdata)
return 0 ;
pdwvw = (DWVW_PRIVATE*) psf->fdata ;
normfact = (psf->norm_float == SF_TRUE) ? ((float) 0x80000000) : 1.0 ;
iptr = (int*) psf->buffer ;
bufferlen = SF_BUFFER_LEN / sizeof (short) ;
while (len > 0)
{ writecount = (len >= bufferlen) ? bufferlen : len ;
for (k = 0 ; k < writecount ; k++)
iptr [k] = lrintf (normfact * ptr [index + k]) ;
count = dwvw_encode_data (pdwvw, iptr, writecount) ;
index += writecount ;
total += count ;
len -= writecount ;
} ;
return total ;
} /* dwvw_write_f */
static sf_count_t
dwvw_write_d (SF_PRIVATE *psf, double *ptr, sf_count_t len)
{ DWVW_PRIVATE *pdwvw ;
int *iptr ;
int k, bufferlen, writecount = 0, count ;
int index = 0, total = 0 ;
double normfact ;
if (! psf->fdata)
return 0 ;
pdwvw = (DWVW_PRIVATE*) psf->fdata ;
normfact = (psf->norm_double == SF_TRUE) ? ((double) 0x80000000) : 1.0 ;
iptr = (int*) psf->buffer ;
bufferlen = SF_BUFFER_LEN / sizeof (short) ;
while (len > 0)
{ writecount = (len >= bufferlen) ? bufferlen : len ;
for (k = 0 ; k < writecount ; k++)
iptr [k] = lrint (normfact * ptr [index + k]) ;
count = dwvw_encode_data (pdwvw, iptr, writecount) ;
index += writecount ;
total += count ;
len -= writecount ;
} ;
return total ;
} /* dwvw_write_d */