shithub: sox

ref: 32736bb3b3a40125b6985844dc1efe280f02dd45
dir: /src/auto.c/

View raw version
/*
 * 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.h"
#include <string.h>

#if defined(DOS) || defined(WIN32)
#define LASTCHAR '\\'
#else
#define LASTCHAR '/'
#endif

int st_autostartread(ft)
ft_t ft;
{
    char *type;
    char header[132];
    int rc;

    type = 0;

    /* Attempt to auto-detect filetype using magic values.  Abort loop
     * and use file extension if any errors are detected.
     */
    if (ft->seekable)
    {
	if (fread(header, 1, sizeof(header), ft->fp) == sizeof(header))
	{

	    fseek(ft->fp, 0L - sizeof header, 1); /* Seek back */
	    type = 0;
	    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) 
	    {
		if (strncmp(header + 8, "AIFF", 4) == 0)
		    type = "aiff";
		else if (strncmp(header + 8, "8SVX", 4) == 0)
		    type = "8svx";
		else if (strncmp(header + 8, "MAUD", 4) == 0)
		    type = "maud";
	    }
	    else if (strncmp(header, "RIFF", 4) == 0 &&
		    strncmp(header + 8, "WAVE", 4) == 0) 
	    {
		type = "wav";
	    }
	    else if (strncmp(header, "Creative Voice File", 19) == 0) 
	    {
		type = "voc";
	    }
	    else if (strncmp(header+65, "FSSD", 4) == 0 &&
		    strncmp(header+128, "HCOM", 4) == 0) 
	    {
		type = "hcom";
	    }
	    else if (strncmp(header, "SOUND", 5) == 0) 
	    {
		type = "sndt";
	    }
	    else if (strncmp(header, "2BIT", 4) == 0) 
	    {
		type = "avr";
	    }
	    else if (strncmp(header, "NIST_1A", 4) == 0) 
	    {
		type = "sph";
	    }
	}
    }

    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) 
ft_t ft;
{
	st_fail_errno(ft,ST_EFMT,"Type AUTO can only be used for input!");
	return(ST_EOF);
}