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/*
This file is part of libextractor.
(C) 2004, 2009 Vidyut Samanta and Christian Grothoff
libextractor is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published
by the Free Software Foundation; either version 2, or (at your
option) any later version.
libextractor 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
General Public License for more details.
You should have received a copy of the GNU General Public License
along with libextractor; see the file COPYING. If not, write to the
Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.
This code was based on bitcollider 0.6.0
(PD) 2004 The Bitzi Corporation
http://bitzi.com/
(PD) 2001 The Bitzi Corporation
Please see file COPYING or http://bitzi.com/publicdomain
for more info.
*/
#include "platform.h"
#include "extractor.h"
#if BIG_ENDIAN_HOST
static short
toLittleEndian16 (short in)
{
char *ptr = (char *) ∈
return ((ptr[1] & 0xFF) << 8) | (ptr[0] & 0xFF);
}
static unsigned int
toLittleEndian32 (unsigned int in)
{
char *ptr = (char *) ∈
return ((ptr[3] & 0xFF) << 24) | ((ptr[2] & 0xFF) << 16) | ((ptr[1] & 0xFF)
<< 8) | (ptr[0]
&
0xFF);
}
#endif
/*
16 4 bytes 0x00000010 // Length of the fmt data (16 bytes)
20 2 bytes 0x0001 // Format tag: 1 = PCM
22 2 bytes <channels> // Channels: 1 = mono, 2 = stereo
24 4 bytes <sample rate> // Samples per second: e.g., 44100
*/
int
EXTRACTOR_wav_extract (const unsigned char *buf,
size_t bufLen,
EXTRACTOR_MetaDataProcessor proc,
void *proc_cls,
const char *options)
{
unsigned short channels;
unsigned short sampleSize;
unsigned int sampleRate;
unsigned int dataLen;
unsigned int samples;
char scratch[256];
if ((bufLen < 44) ||
(buf[0] != 'R' || buf[1] != 'I' ||
buf[2] != 'F' || buf[3] != 'F' ||
buf[8] != 'W' || buf[9] != 'A' ||
buf[10] != 'V' || buf[11] != 'E' ||
buf[12] != 'f' || buf[13] != 'm' || buf[14] != 't' || buf[15] != ' '))
return 0; /* not a WAV file */
channels = *((unsigned short *) &buf[22]);
sampleRate = *((unsigned int *) &buf[24]);
sampleSize = *((unsigned short *) &buf[34]);
dataLen = *((unsigned int *) &buf[40]);
#if BIG_ENDIAN_HOST
channels = toLittleEndian16 (channels);
sampleSize = toLittleEndian16 (sampleSize);
sampleRate = toLittleEndian32 (sampleRate);
dataLen = toLittleEndian32 (dataLen);
#endif
if (sampleSize != 8 && sampleSize != 16)
return 0; /* invalid sample size found in wav file */
if (channels == 0)
return 0; /* invalid channels value -- avoid division by 0! */
samples = dataLen / (channels * (sampleSize >> 3));
snprintf (scratch,
sizeof (scratch),
"%u ms, %d Hz, %s",
(samples < sampleRate)
? (samples * 1000 / sampleRate)
: (samples / sampleRate) * 1000,
sampleRate, channels == 1 ? _("mono") : _("stereo"));
if (0 != proc (proc_cls,
"wav",
EXTRACTOR_METATYPE_RESOURCE_TYPE,
EXTRACTOR_METAFORMAT_UTF8,
"text/plain",
scratch,
strlen (scratch) +1))
return 1;
if (0 != proc (proc_cls,
"wav",
EXTRACTOR_METATYPE_MIMETYPE,
EXTRACTOR_METAFORMAT_UTF8,
"text/plain",
"audio/x-wav",
strlen ("audio/x-wav") +1))
return 1;
return 0;
}
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