ref: c4a08032074cdf097cfb13683efb4cfad74b96c6
dir: /src/auto.c/
/*
* May 19, 1992
* Copyright 1992 Guido van Rossum And Sundry Contributors
* This source code is freely redistributable and may be used for
* any purpose. This copyright notice must be maintained.
* Guido van Rossum And Sundry Contributors are not responsible for
* the consequences of using this software.
*/
/*
* A meta-handler that recognizes most file types by looking in the
* first part of the file. The file must be seekable!
* (IRCAM sound files are not recognized -- these don't seem to be
* used any more -- but this is just laziness on my part.)
*/
#include "st_i.h"
#include <string.h>
#if defined(DOS) || defined(WIN32)
#define LASTCHAR '\\'
#else
#define LASTCHAR '/'
#endif
int st_autostartread(ft_t ft)
{
char *type;
char header[20];
int rc;
int loop;
type = 0;
/* Attempt to auto-detect filetype using magic values. Abort loop
* and use file extension if any errors are detected.
*/
if (ft->seekable)
{
/* Most files only have 4-byte magic headers at first of
* file. So we start checking for those filetypes first.
*/
memset(header,0,4);
if (fread(header, 1, 4, ft->fp) == 4)
{
/* Look for .snd or dns. header of AU files */
if ((strncmp(header, ".snd", 4) == 0) ||
(strncmp(header, "dns.", 4) == 0) ||
((header[0] == '\0') && (strncmp(header+1, "ds.", 3) == 0)))
{
type = "au";
}
else if (strncmp(header, "FORM", 4) == 0)
{
/* Need to read more data to see what type of FORM file */
if (fread(header, 1, 8, ft->fp) == 8)
{
if (strncmp(header + 4, "AIFF", 4) == 0)
type = "aiff";
else if (strncmp(header + 4, "AIFC", 4) == 0)
type = "aiff";
else if (strncmp(header + 4, "8SVX", 4) == 0)
type = "8svx";
else if (strncmp(header + 4, "MAUD", 4) == 0)
type = "maud";
}
}
else if (strncmp(header, "RIFF", 4) == 0)
{
if (fread(header, 1, 8, ft->fp) == 8)
{
if (strncmp(header + 4, "WAVE", 4) == 0)
type = "wav";
}
}
else if (strncmp(header, "Crea", 4) == 0)
{
if (fread(header, 1, 15, ft->fp) == 15)
{
if (strncmp(header, "tive Voice File", 15) == 0)
type = "voc";
}
}
else if (strncmp(header, "SOUN", 4) == 0)
{
/* Check for SOUND magic header */
if (fread(header, 1, 1, ft->fp) == 1 && *header == 'D')
{
/* Once we've found SOUND see if its smp or sndt */
if (fread(header, 1, 12, ft->fp) == 12)
{
if (strncmp(header, " SAMPLE DATA", 12) == 0)
type = "smp";
else
type = "sndt";
}
else
type = "sndt";
}
}
else if (strncmp(header, "2BIT", 4) == 0)
{
type = "avr";
}
else if (strncmp(header, "NIST", 4) == 0)
{
if (fread(header, 1, 3, ft->fp) == 3)
{
if (strncmp(header, "_1A", 3) == 0)
type = "sph";
}
}
else if (strncmp(header, "ALaw", 4) == 0)
{
if (fread(header, 1, 11, ft->fp) == 11)
{
if (strncmp(header, "SoundFile**", 11) == 0)
{
type = "wve";
}
}
}
else if (strncmp(header, "Ogg", 3) == 0)
{
type = "ogg";
}
} /* read 4-byte header */
/* If we didn't find type yet then start looking for file
* formats that the magic header is deeper in the file.
*/
if (type == 0)
{
loop = 61;
while (loop--)
{
if (fread(header, 1, 1, ft->fp) != 1)
loop = 0;
}
if (fread(header, 1, 4, ft->fp) == 4 &&
strncmp(header, "FSSD", 4) == 0)
{
loop = 63;
while (loop--)
{
if (fread(header, 1, 1, ft->fp) != 1)
loop = 0;
}
if (fread(header, 1, 4, ft->fp) == 0 &&
strncmp(header, "HCOM", 4) == 0)
type = "hcom";
}
}
rewind(ft->fp);
} /* if (seekable) */
if (type == 0)
{
/* Use filename extension to determine audio type. */
/* First, chop off any path portions of filename. This
* prevents the next search from considering that part. */
if ((type = strrchr(ft->filename, LASTCHAR)) == NULL)
type = ft->filename;
/* Now look for an filename extension */
if ((type = strrchr(type, '.')) != NULL)
type++;
else
type = NULL;
}
ft->filetype = type;
rc = st_gettype(ft); /* Change ft->h to the new format */
if(rc != ST_SUCCESS)
{
st_fail_errno(ft,ST_EFMT,"Do not understand format type: %s\n",type);
return (rc);
}
st_report("Detected file format type: %s\n", type);
return ((* ft->h->startread)(ft));
}
int st_autostartwrite(ft_t ft)
{
st_fail_errno(ft,ST_EFMT,"Type AUTO can only be used for input!");
return(ST_EOF);
}