ref: e8b75b81ae94f3d5830e533ecb56d3bbb2ac7a9d
parent: 3e65ee7b61f23fd4076f8849be0618d267002efe
author: cbagwell <cbagwell>
date: Thu Nov 10 10:05:43 EST 2005
updating skeleton file a little.
--- a/src/skel.c
+++ b/src/skel.c
@@ -14,63 +14,93 @@
#include "st_i.h"
/* Private data for SKEL file */
-typedef struct skelstuff {- int rest; /* bytes remaining in current block */
+typedef struct skelstuff
+{+ st_size_t samples_remaining;
} *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.
+ * 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;
+ 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 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);
+ /*
+ * If your format is headerless and has fixed values for
+ * the following items, you can hard code them here (see cdr.c).
+ * If your format contains a header with format information
+ * then you should set it here.
+ */
+ ft->info.rate = 44100L;
+ ft->info.size = ST_SIZE_BYTE or WORD ...;
+ ft->info.encoding = ST_ENCODING_UNSIGNED or SIGN2 ...;
+ ft->info.channels = 1 or 2 or 4;
+ ft->comment = malloc(size_of_comment);
+ strcpy(ft->comment, "any comment in file header.");
+
+ /* If your format doesn't have a header then samples_in_file
+ * can be determined by the file size.
+ */
+ samples_in_file = st_filelength(ft)/ft->info.size;
+
+ /* If you can detect the length of your file, record it here. */
+ ft->length = samples_in_file;
+ sk->remaining_samples = samples_in_file;
+
+ return (ST_SUCCESS);
}
/*
* Read up to len samples from file.
- * Convert to signed longs.
+ * Convert to st_sample_t.
* 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;
+ 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;
-}
+ /* Always return a full frame of audio data */
+ if (len % ft->info.size)
+ len -= (len % ft->info.size);
+
+ for(; done < len; done++) {+ if no more samples
+ break
+ get a sample
+ switch (ft->info.size)
+ {+ case ST_SIZE_BYTE:
+ switch (ft->info.encoding)
+ {+ case ST_ENCODING_UNSIGNED;
+ *buf++ = ST_UNSIGNED_BYTE_TO_SAMPLE(sample);
+ break;
+ }
+ break;
+ }
+ }
+ if (done == 0)
+ return ST_EOF;
+ else
+ return done;
+}
+
/*
* Do anything required when you stop reading samples.
* Don't close input file!
@@ -82,46 +112,73 @@
int st_skelstartwrite(ft_t ft)
{- skel_t sk = (skel_t) ft->priv;
+ 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 you have to seek around the output file. */
+ /* If header contains a length value then seeking will be
+ * required. Instead of failing, its sometimes nice to
+ * just set the length to max value and not fail.
+ */
+ 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);
-
+ if (ft->info.rate != 44100L)
+ {+ st_fail_errno(ft, ST_EVALUE, "Output. skel file must have a sample rate of 44100");
+ }
+
+ if (ft->info.size == -1)
+ {+ st_fail_errno(ft, ST_EVALUE, "Did not specify a size for .skel output file");
+ return (ST_EOF);
+ }
+ error check ft->info.encoding;
+ error check ft->info.channels;
+
+ /* 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;
+ skel_t sk = (skel_t) ft->priv;
+ st_ssize_t len = 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);
-
+ switch (ft->info.size)
+ {+ case ST_SIZE_BYTE:
+ switch (ft->info.encoding)
+ {+ case ST_ENCODING_UNSIGNED:
+ while(len--)
+ {+ len = st_writeb(ft, ST_SAMPLE_TO_UNSIGNED_BYTE(*buff++));
+ if (len == ST_EOF)
+ break;
+ }
+ break;
+ }
+ break;
+ }
+
+ if (len == ST_EOF)
+ return ST_EOF;
+ else
+ 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. */
+ /* 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);
}