ref: 4976f1410cc69ae475fdaedc574a404ed606dafd
dir: /src/skel.c/
/*
* July 5, 1991
* Copyright 1991 Lance Norskog And Sundry Contributors
* This source code is freely redistributable and may be used for
* any purpose. This copyright notice must be maintained.
* Lance Norskog And Sundry Contributors are not responsible for
* the consequences of using this software.
*/
/*
* Sound Tools skeleton file format driver.
*/
#include "st_i.h"
/* Private data for SKEL file */
typedef struct skelstuff {
int rest; /* bytes remaining in current block */
} *skel_t;
/*
* Do anything required before you start reading samples.
* Read file header.
* Find out sampling rate,
* size and encoding of samples,
* mono/stereo/quad.
*/
int st_skelstartread(ft_t ft)
{
skel_t sk = (skel_t) ft->priv;
/* If you need to seek around the input file. */
if (! ft->seekable)
{
st_fail_errno(ft,ST_EVALUE,"SKEL input file must be a file, not a pipe");
return (ST_EOF);
}
/*
* If your format specifies or your file header contains
* any of the following information.
*/
ft->info.rate =
ft->info.size = BYTE or WORD ...;
ft->info.encoding = UNSIGNED or SIGN2 ...;
ft->info.channels = 1 or 2 or 4;
ft->comment = any comment in file header.
return (ST_SUCCESS);
}
/*
* Read up to len samples from file.
* Convert to signed longs.
* Place in buf[].
* Return number of samples read.
*/
st_ssize_t st_skelread(ft_t ft, st_sample_t *buf, st_ssize_t len)
{
skel_t sk = (skel_t) ft->priv;
int done = 0;
st_sample_t l;
for(; done < len; done++) {
if no more samples
break
get a sample
l = sample converted to signed long
*buf++ = l;
}
return done;
}
/*
* Do anything required when you stop reading samples.
* Don't close input file!
*/
int skelstopread(ft_t ft)
{
return (ST_SUCCESS);
}
int st_skelstartwrite(ft_t ft)
{
skel_t sk = (skel_t) ft->priv;
/* If you have to seek around the output file */
if (! ft->seekable) {
st_fail_errno(ft,ST_EVALUE,"Output .skel file must be a file, not a pipe");
return (ST_EOF);
}
/* If your format specifies any of the following info. */
ft->info.rate =
ft->info.size = BYTE or WORD ...;
ft->info.encoding = UNSIGNED or SIGN2 ...;
ft->info.channels = 1 or 2 or 4;
/* Write file header, if any */
/* Write comment field, if any */
return(ST_SUCCESS);
}
st_ssize_t st_skelwrite(ft_t ft, st_sample_t *buf, st_ssize_t len)
{
skel_t sk = (skel_t) ft->priv;
register int datum;
int abs;
int done = 0;
while(len--)
st_writeb(ft, (*buf++ >> 24) ^ 0x80);
/* If you cannot write out all of the supplied samples, */
/* st_fail_errno(ft,ST_EVALUE,"SKEL: Can't write all samples to %s", ft->filename); */
/* return (ST_EOF); */
return (ST_SUCCESS);
}
int st_skelstopwrite(ft_t ft)
{
/* All samples are already written out. */
/* If file header needs fixing up, for example it needs the */
/* the number of samples in a field, seek back and write them here. */
return (ST_SUCCESS);
}