alaw.c

SIP（Session Initiation Protocol）是由IETF定义

/*
** Copyright (C) 1999-2001 Erik de Castro Lopo <[e-mail]>
**  
** 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	<unistd.h>

#include	"sndfile.h"
#include	"common.h"

static int		alaw_read_alaw2s (SF_PRIVATE *psf, short *ptr, unsigned int len) ;
static int		alaw_read_alaw2i (SF_PRIVATE *psf, int *ptr, unsigned int len) ;
static int		alaw_read_alaw2f (SF_PRIVATE *psf, float *ptr, unsigned int len) ;
static int		alaw_read_alaw2d (SF_PRIVATE *psf, double *ptr, unsigned int len, int normalize) ;

static int		alaw_write_s2alaw (SF_PRIVATE *psf, short *ptr, unsigned int len) ;
static int		alaw_write_i2alaw (SF_PRIVATE *psf, int *ptr, unsigned int len) ;
static int		alaw_write_f2alaw (SF_PRIVATE *psf, float *ptr, unsigned int len) ;
static int		alaw_write_d2alaw (SF_PRIVATE *psf, double *ptr, unsigned int len, int normalize) ;

static  void    alaw2s_array      (unsigned char *buffer, unsigned int count, short *ptr, unsigned int index) ;
static  void    alaw2i_array      (unsigned char *buffer, unsigned int count, int *ptr, unsigned int index) ;
static  void    alaw2f_array      (unsigned char *buffer, unsigned int count, float *ptr, unsigned int index, float normfact) ;
static  void    alaw2d_array      (unsigned char *buffer, unsigned int count, double *ptr, unsigned int index, double normfact) ;

static  void    s2alaw_array      (short *buffer, unsigned int count, unsigned char *ptr, unsigned int index) ;
static  void    i2alaw_array      (int *buffer, unsigned int count, unsigned char *ptr, unsigned int index) ;
static  void    f2alaw_array      (float *buffer, unsigned int count, unsigned char *ptr, unsigned int index, float normfact) ;
static  void    d2alaw_array      (double *buffer, unsigned int count, unsigned char *ptr, unsigned int index, double normfact) ;

int
alaw_read_init (SF_PRIVATE *psf)
{
	psf->read_short  = (func_short)  alaw_read_alaw2s ;
	psf->read_int    = (func_int)    alaw_read_alaw2i ;
	psf->read_float  = (func_float)  alaw_read_alaw2f ;
	psf->read_double = (func_double) alaw_read_alaw2d ;

	return 0 ;
} /* alaw_read_init */

int
alaw_write_init (SF_PRIVATE *psf)
{
	psf->write_short  = (func_short)  alaw_write_s2alaw ;
	psf->write_int    = (func_int)    alaw_write_i2alaw ;
	psf->write_float  = (func_float)  alaw_write_f2alaw ;
	psf->write_double = (func_double) alaw_write_d2alaw ;

	return 0 ;
} /* alaw_read_init */

static int
alaw_read_alaw2s (SF_PRIVATE *psf, short *ptr, unsigned int len)
{	unsigned int readcount, thisread, index = 0 ;
	int		bytecount, bufferlen ;
	int		total = 0 ;

	bufferlen = (SF_BUFFER_LEN / psf->blockwidth) * psf->blockwidth ;
	bytecount = len * psf->bytewidth ;
	while (bytecount > 0)
	{	readcount = (bytecount >= bufferlen) ? bufferlen : bytecount ;
		thisread = fread (psf->buffer, 1, readcount, psf->file) ;
		alaw2s_array ((unsigned char*) (psf->buffer), thisread / psf->bytewidth, ptr, index) ;
		total += thisread ;
		if (thisread < readcount)
			break ;
		index += thisread / psf->bytewidth ;
		bytecount -= thisread ;
		} ;

	total /= psf->bytewidth ;
	if (total < len)
		psf->error = SFE_SHORT_READ ;
	
	return total ;
} /* alaw_read_alaw2s */

static int
alaw_read_alaw2i (SF_PRIVATE *psf, int *ptr, unsigned int len)
{	unsigned int readcount, thisread, index = 0 ;
	int		bytecount, bufferlen ;
	int		total = 0 ;

	bufferlen = (SF_BUFFER_LEN / psf->blockwidth) * psf->blockwidth ;
	bytecount = len * psf->bytewidth ;
	while (bytecount > 0)
	{	readcount = (bytecount >= bufferlen) ? bufferlen : bytecount ;
		thisread = fread (psf->buffer, 1, readcount, psf->file) ;
		alaw2i_array ((unsigned char*) (psf->buffer), thisread / psf->bytewidth, ptr, index) ;
		total += thisread ;
		if (thisread < readcount)
			break ;
		index += thisread / psf->bytewidth ;
		bytecount -= thisread ;
		} ;

	total /= psf->bytewidth ;
	if (total < len)
		psf->error = SFE_SHORT_READ ;
	
	return total ;
} /* alaw_read_alaw2i */

static int
alaw_read_alaw2f (SF_PRIVATE *psf, float *ptr, unsigned int len)
{	unsigned int readcount, thisread, index = 0 ;
	int		bytecount, bufferlen ;
	int		total = 0 ;

	bufferlen = (SF_BUFFER_LEN / psf->blockwidth) * psf->blockwidth ;
	bytecount = len * psf->bytewidth ;
	while (bytecount > 0)
	{	readcount = (bytecount >= bufferlen) ? bufferlen : bytecount ;
		thisread = fread (psf->buffer, 1, readcount, psf->file) ;
		alaw2f_array ((unsigned char*) (psf->buffer), thisread / psf->bytewidth, ptr, index, 1.0) ;
		total += thisread ;
		if (thisread < readcount)
			break ;
		index += thisread / psf->bytewidth ;
		bytecount -= thisread ;
		} ;

	total /= psf->bytewidth ;
	if (total < len)
		psf->error = SFE_SHORT_READ ;
	
	return total ;
} /* alaw_read_alaw2f */

static int
alaw_read_alaw2d (SF_PRIVATE *psf, double *ptr, unsigned int len, int normalize)
{	unsigned int readcount, thisread, index = 0 ;
	int		bytecount, bufferlen ;
	int		total = 0 ;
	double	normfact ;
	
	normfact = (normalize ? 1.0 / ((double) 0x8000) : 1.0) ;
	bufferlen = (SF_BUFFER_LEN / psf->blockwidth) * psf->blockwidth ;
	bytecount = len * psf->bytewidth ;
	while (bytecount > 0)
	{	readcount = (bytecount >= bufferlen) ? bufferlen : bytecount ;
		thisread = fread (psf->buffer, 1, readcount, psf->file) ;
		alaw2d_array ((unsigned char*) (psf->buffer), thisread / psf->bytewidth, ptr, index, normfact) ;
		total += thisread ;
		if (thisread < readcount)
			break ;
		index += thisread / psf->bytewidth ;
		bytecount -= thisread ;
		} ;

	total /= psf->bytewidth ;
	if (total < len)
		psf->error = SFE_SHORT_READ ;
	
	return total ;
} /* alaw_read_alaw2d */

/*=============================================================================================
*/

static int
alaw_write_s2alaw	(SF_PRIVATE *psf, short *ptr, unsigned int len)
{	unsigned int	writecount, thiswrite, index = 0 ;
	int		bytecount, bufferlen ;
	int		total = 0 ;

	bufferlen = (SF_BUFFER_LEN / psf->blockwidth) * psf->blockwidth ;
	bytecount = len * psf->bytewidth ;
	while (bytecount > 0)
	{	writecount = (bytecount >= bufferlen) ? bufferlen : bytecount ;
		s2alaw_array (ptr, index, (unsigned char*) (psf->buffer), writecount / psf->bytewidth) ;
		thiswrite = fwrite (psf->buffer, 1, writecount, psf->file) ;
		total += thiswrite ;
		if (thiswrite < writecount)
			break ;
		index += thiswrite / psf->bytewidth ;
		bytecount -= thiswrite ;
		} ;

	total /= psf->bytewidth ;
	if (total < len)
		psf->error = SFE_SHORT_READ ;
	
	return total ;
} /* alaw_write_s2alaw */

static int
alaw_write_i2alaw	(SF_PRIVATE *psf, int *ptr, unsigned int len)
{	unsigned int	writecount, thiswrite, index = 0 ;
	int		bytecount, bufferlen ;
	int		total = 0 ;

	bufferlen = (SF_BUFFER_LEN / psf->blockwidth) * psf->blockwidth ;
	bytecount = len * psf->bytewidth ;
	while (bytecount > 0)
	{	writecount = (bytecount >= bufferlen) ? bufferlen : bytecount ;
		i2alaw_array (ptr, index, (unsigned char*) (psf->buffer), writecount / psf->bytewidth) ;
		thiswrite = fwrite (psf->buffer, 1, writecount, psf->file) ;
		total += thiswrite ;
		if (thiswrite < writecount)
			break ;
		index += thiswrite / psf->bytewidth ;
		bytecount -= thiswrite ;
		} ;

	total /= psf->bytewidth ;
	if (total < len)
		psf->error = SFE_SHORT_READ ;
	
	return total ;
} /* alaw_write_i2alaw */

static int
alaw_write_f2alaw	(SF_PRIVATE *psf, float *ptr, unsigned int len)
{	unsigned int	writecount, thiswrite, index = 0 ;
	int		bytecount, bufferlen ;
	int		total = 0 ;

	bufferlen = (SF_BUFFER_LEN / psf->blockwidth) * psf->blockwidth ;
	bytecount = len * psf->bytewidth ;
	while (bytecount > 0)
	{	writecount = (bytecount >= bufferlen) ? bufferlen : bytecount ;
		f2alaw_array (ptr, index, (unsigned char*) (psf->buffer), writecount / psf->bytewidth, 1.0) ;
		thiswrite = fwrite (psf->buffer, 1, writecount, psf->file) ;
		total += thiswrite ;
		if (thiswrite < writecount)
			break ;
		index += thiswrite / psf->bytewidth ;
		bytecount -= thiswrite ;
		} ;

	total /= psf->bytewidth ;
	if (total < len)
		psf->error = SFE_SHORT_READ ;
	
	return total ;
} /* alaw_write_f2alaw */

static int
alaw_write_d2alaw	(SF_PRIVATE *psf, double *ptr, unsigned int len, int normalize)
{	unsigned int	writecount, thiswrite, index = 0 ;
	int		bytecount, bufferlen ;
	int		total = 0 ;
	double	normfact ;
	
	normfact = (normalize ? ((double) 0x8000) : 1.0) ;

	bufferlen = (SF_BUFFER_LEN / psf->blockwidth) * psf->blockwidth ;
	bytecount = len * psf->bytewidth ;
	while (bytecount > 0)
	{	writecount = (bytecount >= bufferlen) ? bufferlen : bytecount ;
		d2alaw_array (ptr, index, (unsigned char*) (psf->buffer), writecount / psf->bytewidth, normfact) ;
		thiswrite = fwrite (psf->buffer, 1, writecount, psf->file) ;
		total += thiswrite ;
		if (thiswrite < writecount)
			break ;
		index += thiswrite / psf->bytewidth ;
		bytecount -= thiswrite ;
		} ;

	total /= psf->bytewidth ;
	if (total < len)
		psf->error = SFE_SHORT_READ ;
	
	return total ;
} /* alaw_write_d2alaw */

/*=============================================================================================
 *	Private static functions and data.
 */

static	
short	alaw_decode [128] =
{	 -5504,  -5248,  -6016,  -5760,  -4480,  -4224,  -4992,  -4736, 
	 -7552,  -7296,  -8064,  -7808,  -6528,  -6272,  -7040,  -6784, 
	 -2752,  -2624,  -3008,  -2880,  -2240,  -2112,  -2496,  -2368,