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    /*
    
     * Asterisk -- An open source telephony toolkit.
    
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     *
    
     * Copyright (C) 1999 - 2005, Digium, Inc.
     *
     * Mark Spencer <markster@digium.com>
    
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     *
    
     * See http://www.asterisk.org for more information about
     * the Asterisk project. Please do not directly contact
     * any of the maintainers of this project for assistance;
     * the project provides a web site, mailing lists and IRC
     * channels for your use.
    
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     *
     * This program is free software, distributed under the terms of
    
     * the GNU General Public License Version 2. See the LICENSE file
     * at the top of the source tree.
     */
    
    
     * \brief Work with WAV in the proprietary Microsoft format.
    
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     * Microsoft WAV format (8000hz Signed Linear)
     * \arg File name extension: wav (lower case)
     * \ingroup formats
    
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     */
    
    /*** MODULEINFO
    	<support_level>core</support_level>
     ***/
    
    
    #include "asterisk/mod_format.h"
    
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    #include "asterisk/module.h"
    #include "asterisk/endian.h"
    
    #include "asterisk/format_cache.h"
    #include "asterisk/format.h"
    #include "asterisk/codec.h"
    
    /* Some Ideas for this code came from makewave.c by Jeffrey Chilton */
    
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    /* Portions of the conversion code are by guido@sienanet.it */
    
    #define	WAV_BUF_SIZE	320
    
    
    struct wav_desc {	/* format-specific parameters */
    
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    	int bytes;
    	int lasttimeout;
    
    	int maxlen;
    
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    	struct timeval last;
    
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    #define BLOCKSIZE 160
    
    #if __BYTE_ORDER == __LITTLE_ENDIAN
    #define htoll(b) (b)
    #define htols(b) (b)
    #define ltohl(b) (b)
    #define ltohs(b) (b)
    #else
    #if __BYTE_ORDER == __BIG_ENDIAN
    
    #define htoll(b) \
    	(((((b)      ) & 0xFF) << 24) | \
    	((( (b) >>  8) & 0xFF) << 16) | \
    	((( (b) >> 16) & 0xFF) <<  8) | \
    	((( (b) >> 24) & 0xFF)      ))
    
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    #define htols(b) \
    
    	(((((b)      ) & 0xFF) <<  8) | \
    	((( (b) >>  8) & 0xFF)      ))
    
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    #define ltohl(b) htoll(b)
    #define ltohs(b) htols(b)
    #else
    #error "Endianess not defined"
    #endif
    #endif
    
    
    
    static int check_header_fmt(FILE *f, int hsize, int hz)
    
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    {
    
    	unsigned short format, chans, bysam, bisam;
    	unsigned int freq, bysec;
    
    	if (hsize < 16) {
    
    		ast_log(LOG_WARNING, "Unexpected header size %d\n", hsize);
    
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    		return -1;
    	}
    
    	if (fread(&format, 1, 2, f) != 2) {
    
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    		ast_log(LOG_WARNING, "Read failed (format)\n");
    		return -1;
    	}
    	if (ltohs(format) != 1) {
    
    		ast_log(LOG_WARNING, "Not a supported wav file format (%d). Only PCM encoded, 16 bit, mono, 8kHz/16kHz files are supported with a lowercase '.wav' extension.\n", ltohs(format));
    
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    		return -1;
    	}
    
    	if (fread(&chans, 1, 2, f) != 2) {
    
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    		ast_log(LOG_WARNING, "Read failed (format)\n");
    		return -1;
    	}
    	if (ltohs(chans) != 1) {
    		ast_log(LOG_WARNING, "Not in mono %d\n", ltohs(chans));
    		return -1;
    	}
    
    	if (fread(&freq, 1, 4, f) != 4) {
    
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    		ast_log(LOG_WARNING, "Read failed (freq)\n");
    		return -1;
    	}
    
    	freq = ltohl(freq);
    	if ((freq != 8000 && freq != 16000) || freq != hz) {
    		ast_log(LOG_WARNING, "Unexpected frequency mismatch %d (expecting %d)\n", freq, hz);
    
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    		return -1;
    	}
    	/* Ignore the byte frequency */
    
    	if (fread(&bysec, 1, 4, f) != 4) {
    
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    		ast_log(LOG_WARNING, "Read failed (BYTES_PER_SECOND)\n");
    		return -1;
    	}
    	/* Check bytes per sample */
    
    	if (fread(&bysam, 1, 2, f) != 2) {
    
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    		ast_log(LOG_WARNING, "Read failed (BYTES_PER_SAMPLE)\n");
    		return -1;
    	}
    	if (ltohs(bysam) != 2) {
    		ast_log(LOG_WARNING, "Can only handle 16bits per sample: %d\n", ltohs(bysam));
    		return -1;
    	}
    
    	if (fread(&bisam, 1, 2, f) != 2) {
    
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    		ast_log(LOG_WARNING, "Read failed (Bits Per Sample): %d\n", ltohs(bisam));
    
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    		return -1;
    	}
    
    	/* Skip any additional header */
    
    	if (fseek(f,hsize-16,SEEK_CUR) == -1 ) {
    		ast_log(LOG_WARNING, "Failed to skip remaining header bytes: %d\n", hsize-16 );
    
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    		return -1;
    	}
    
    	return 0;
    }
    
    static int check_header(FILE *f, int hz)
    {
    	int type, size, formtype;
    	int data;
    	if (fread(&type, 1, 4, f) != 4) {
    		ast_log(LOG_WARNING, "Read failed (type)\n");
    		return -1;
    	}
    	if (fread(&size, 1, 4, f) != 4) {
    		ast_log(LOG_WARNING, "Read failed (size)\n");
    		return -1;
    	}
    
    #if __BYTE_ORDER == __BIG_ENDIAN
    
    	size = ltohl(size);
    
    	if (fread(&formtype, 1, 4, f) != 4) {
    		ast_log(LOG_WARNING, "Read failed (formtype)\n");
    		return -1;
    	}
    	if (memcmp(&type, "RIFF", 4)) {
    		ast_log(LOG_WARNING, "Does not begin with RIFF\n");
    		return -1;
    	}
    	if (memcmp(&formtype, "WAVE", 4)) {
    		ast_log(LOG_WARNING, "Does not contain WAVE\n");
    		return -1;
    	}
    
    	/* Skip any facts and get the first data block */
    
    	for(;;)
    
    		/* Begin data chunk */
    		if (fread(&buf, 1, 4, f) != 4) {
    
    			ast_log(LOG_WARNING, "Read failed (block header format)\n");
    
    		}
    		/* Data has the actual length of data in it */
    		if (fread(&data, 1, 4, f) != 4) {
    
    			ast_log(LOG_WARNING, "Read failed (block '%.4s' header length)\n", buf);
    
    		}
    #if __BYTE_ORDER == __BIG_ENDIAN
    		data = ltohl(data);
    #endif
    
    		if (memcmp(&buf, "fmt ", 4) == 0) {
    			if (check_header_fmt(f, data, hz))
    				return -1;
    			continue;
    		}
    
    		if(memcmp(buf, "data", 4) == 0 )
    
    		ast_debug(1, "Skipping unknown block '%.4s'\n", buf);
    
    		if (fseek(f,data,SEEK_CUR) == -1 ) {
    
    			ast_log(LOG_WARNING, "Failed to skip '%.4s' block: %d\n", buf, data);
    
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    	}
    
    #if 0
    	curpos = lseek(fd, 0, SEEK_CUR);
    	truelength = lseek(fd, 0, SEEK_END);
    	lseek(fd, curpos, SEEK_SET);
    	truelength -= curpos;
    
    	return data;
    
    static int update_header(FILE *f)
    
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    {
    
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    	off_t cur,end;
    	int datalen,filelen,bytes;
    
    	cur = ftello(f);
    
    	end = ftello(f);
    
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    	/* data starts 44 bytes in */
    	bytes = end - 44;
    	datalen = htoll(bytes);
    	/* chunk size is bytes of data plus 36 bytes of header */
    	filelen = htoll(36 + bytes);
    
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    	if (cur < 0) {
    		ast_log(LOG_WARNING, "Unable to find our position\n");
    		return -1;
    	}
    
    	if (fseek(f, 4, SEEK_SET)) {
    
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    		ast_log(LOG_WARNING, "Unable to set our position\n");
    		return -1;
    	}
    
    	if (fwrite(&filelen, 1, 4, f) != 4) {
    
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    		ast_log(LOG_WARNING, "Unable to set write file size\n");
    		return -1;
    	}
    
    	if (fseek(f, 40, SEEK_SET)) {
    
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    		ast_log(LOG_WARNING, "Unable to set our position\n");
    		return -1;
    	}
    
    	if (fwrite(&datalen, 1, 4, f) != 4) {
    
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    		ast_log(LOG_WARNING, "Unable to set write datalen\n");
    		return -1;
    	}
    
    	if (fseeko(f, cur, SEEK_SET)) {
    
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    		ast_log(LOG_WARNING, "Unable to return to position\n");
    		return -1;
    	}
    	return 0;
    }
    
    
    static int write_header(FILE *f, int writehz)
    
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    {
    
    	unsigned int hz;
    	unsigned int bhz;
    
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    	unsigned int hs = htoll(16);
    	unsigned short fmt = htols(1);
    	unsigned short chans = htols(1);
    	unsigned short bysam = htols(2);
    	unsigned short bisam = htols(16);
    	unsigned int size = htoll(0);
    
    
    	if (writehz == 16000) {
    		hz = htoll(16000);
    		bhz = htoll(32000);
    	} else {
    		hz = htoll(8000);
    		bhz = htoll(16000);
    	}
    
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    	/* Write a wav header, ignoring sizes which will be filled in later */
    
    	fseek(f,0,SEEK_SET);
    	if (fwrite("RIFF", 1, 4, f) != 4) {
    
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    		ast_log(LOG_WARNING, "Unable to write header\n");
    		return -1;
    	}
    
    	if (fwrite(&size, 1, 4, f) != 4) {
    
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    		ast_log(LOG_WARNING, "Unable to write header\n");
    		return -1;
    	}
    
    	if (fwrite("WAVEfmt ", 1, 8, f) != 8) {
    
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    		ast_log(LOG_WARNING, "Unable to write header\n");
    		return -1;
    	}
    
    	if (fwrite(&hs, 1, 4, f) != 4) {
    
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    		ast_log(LOG_WARNING, "Unable to write header\n");
    		return -1;
    	}
    
    	if (fwrite(&fmt, 1, 2, f) != 2) {
    
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    		ast_log(LOG_WARNING, "Unable to write header\n");
    		return -1;
    	}
    
    	if (fwrite(&chans, 1, 2, f) != 2) {
    
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    		ast_log(LOG_WARNING, "Unable to write header\n");
    		return -1;
    	}
    
    	if (fwrite(&hz, 1, 4, f) != 4) {
    
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    		ast_log(LOG_WARNING, "Unable to write header\n");
    		return -1;
    	}
    
    	if (fwrite(&bhz, 1, 4, f) != 4) {
    
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    		ast_log(LOG_WARNING, "Unable to write header\n");
    		return -1;
    	}
    
    	if (fwrite(&bysam, 1, 2, f) != 2) {
    
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    		ast_log(LOG_WARNING, "Unable to write header\n");
    		return -1;
    	}
    
    	if (fwrite(&bisam, 1, 2, f) != 2) {
    
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    		ast_log(LOG_WARNING, "Unable to write header\n");
    		return -1;
    	}
    
    	if (fwrite("data", 1, 4, f) != 4) {
    
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    		ast_log(LOG_WARNING, "Unable to write header\n");
    		return -1;
    	}
    
    	if (fwrite(&size, 1, 4, f) != 4) {
    
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    		ast_log(LOG_WARNING, "Unable to write header\n");
    		return -1;
    	}
    	return 0;
    }
    
    
    static int wav_open(struct ast_filestream *s)
    
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    {
    	/* We don't have any header to read or anything really, but
    	   if we did, it would go here.  We also might want to check
    	   and be sure it's a valid file.  */
    
    	struct wav_desc *tmp = s->_private;
    	unsigned int sample_rate = ast_format_get_sample_rate(s->fmt->format);
    
    	tmp->maxlen = check_header(s->f, sample_rate);
    	if (tmp->maxlen < 0) {
    
    	}
    
    	tmp->hz = sample_rate;
    
    static int wav_rewrite(struct ast_filestream *s, const char *comment)
    
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    {
    	/* We don't have any header to read or anything really, but
    	   if we did, it would go here.  We also might want to check
    	   and be sure it's a valid file.  */
    
    	struct wav_desc *tmp = (struct wav_desc *)s->_private;
    
    	tmp->hz = ast_format_get_sample_rate(s->fmt->format);
    
    	if (write_header(s->f,tmp->hz))
    
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    }
    
    static void wav_close(struct ast_filestream *s)
    {
    
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    	char zero = 0;
    
    	struct wav_desc *fs = (struct wav_desc *)s->_private;
    
    	if (s->mode == O_RDONLY) {
    
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    	/* Pad to even length */
    
    		if (fwrite(&zero, 1, 1, s->f) != 1) {
    
    			ast_log(LOG_WARNING, "fwrite() failed: %s\n", strerror(errno));
    		}
    	}
    
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    static struct ast_frame *wav_read(struct ast_filestream *s, int *whennext)
    
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    {
    
    	int samples;	/* actual samples read */
    
    #if __BYTE_ORDER == __BIG_ENDIAN
    
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    	int x;
    
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    	/* Send a frame from the file to the appropriate channel */
    
    	struct wav_desc *fs = (struct wav_desc *)s->_private;
    
    	bytes = (fs->hz == 16000 ? (WAV_BUF_SIZE * 2) : WAV_BUF_SIZE);
    
    
    	here = ftello(s->f);
    
    	if (fs->maxlen - here < bytes)		/* truncate if necessary */
    		bytes = fs->maxlen - here;
    
    	if (bytes <= 0) {
    		return NULL;
    	}
    
    /* 	ast_debug(1, "here: %d, maxlen: %d, bytes: %d\n", here, s->maxlen, bytes); */
    
    	AST_FRAME_SET_BUFFER(&s->fr, s->buf, AST_FRIENDLY_OFFSET, bytes);
    
    	if ((res = fread(s->fr.data.ptr, 1, s->fr.datalen, s->f)) == 0) {
    		if (res) {
    			ast_log(LOG_WARNING, "Short read of %s data (expected %d bytes, read %zu): %s\n",
    					ast_format_get_name(s->fr.subclass.format), s->fr.datalen, res,
    					strerror(errno));
    
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    		return NULL;
    
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    	}
    
    	s->fr.datalen = res;
    	s->fr.samples = samples = res / 2;
    
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    #if __BYTE_ORDER == __BIG_ENDIAN
    
    	tmp = (short *)(s->fr.data.ptr);
    
    	/* file format is little endian so we need to swap */
    
    	for( x = 0; x < samples; x++)
    
    		tmp[x] = (tmp[x] << 8) | ((tmp[x] & 0xff00) >> 8);
    
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    #endif
    
    
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    	return &s->fr;
    
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    }
    
    static int wav_write(struct ast_filestream *fs, struct ast_frame *f)
    {
    
    	short tmp[16000], *tmpi;
    
    	struct wav_desc *s = (struct wav_desc *)fs->_private;
    
    	if (!f->datalen)
    		return -1;
    
    #if __BYTE_ORDER == __BIG_ENDIAN
    	/* swap and write */
    
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    	if (f->datalen > sizeof(tmp)) {
    		ast_log(LOG_WARNING, "Data length is too long\n");
    		return -1;
    	}
    
    	for (x=0; x < f->datalen/2; x++)
    
    		tmp[x] = (tmpi[x] << 8) | ((tmpi[x] & 0xff00) >> 8);
    
    	if ((res = fwrite(tmp, 1, f->datalen, fs->f)) != f->datalen ) {
    
    	if ((res = fwrite(f->data.ptr, 1, f->datalen, fs->f)) != f->datalen ) {
    
    		ast_log(LOG_WARNING, "Bad write (%d): %s\n", res, strerror(errno));
    
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    		return -1;
    
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    	}
    
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    	return 0;
    
    static int wav_seek(struct ast_filestream *fs, off_t sample_offset, int whence)
    
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    {
    
    	off_t min = WAV_HEADER_SIZE, max, cur, offset = 0, samples;
    
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    	samples = sample_offset * 2; /* SLINEAR is 16 bits mono, so sample_offset * 2 = bytes */
    
    
    	if ((cur = ftello(fs->f)) < 0) {
    		ast_log(AST_LOG_WARNING, "Unable to determine current position in wav filestream %p: %s\n", fs, strerror(errno));
    		return -1;
    	}
    
    	if (fseeko(fs->f, 0, SEEK_END) < 0) {
    		ast_log(AST_LOG_WARNING, "Unable to seek to end of wav filestream %p: %s\n", fs, strerror(errno));
    		return -1;
    	}
    
    
    		ast_log(AST_LOG_WARNING, "Unable to determine max position in wav filestream %p: %s\n", fs, strerror(errno));
    		return -1;
    	}
    
    
    	if (whence == SEEK_SET) {
    
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    		offset = samples + min;
    
    	} else if (whence == SEEK_CUR || whence == SEEK_FORCECUR) {
    
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    		offset = samples + cur;
    
    	} else if (whence == SEEK_END) {
    
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    		offset = max - samples;
    
    	}
    	if (whence != SEEK_FORCECUR) {
    
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    		offset = (offset > max)?max:offset;
    	}
    
    	/* always protect the header space. */
    
    	offset = (offset < min)?min:offset;
    
    	return fseeko(fs->f, offset, SEEK_SET);
    
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    }
    
    static int wav_trunc(struct ast_filestream *fs)
    {
    
    	int fd;
    	off_t cur;
    
    	if ((fd = fileno(fs->f)) < 0) {
    		ast_log(AST_LOG_WARNING, "Unable to determine file descriptor for wav filestream %p: %s\n", fs, strerror(errno));
    		return -1;
    	}
    
    	if ((cur = ftello(fs->f)) < 0) {
    
    		ast_log(AST_LOG_WARNING, "Unable to determine current position in wav filestream %p: %s\n", fs, strerror(errno));
    		return -1;
    	}
    	/* Truncate file to current length */
    	if (ftruncate(fd, cur)) {
    
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    		return -1;
    
    	return update_header(fs->f);
    
    static off_t wav_tell(struct ast_filestream *fs)
    
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    {
    	off_t offset;
    
    	offset = ftello(fs->f);
    
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    	/* subtract header size to get samples, then divide by 2 for 16 bit samples */
    	return (offset - 44)/2;
    }
    
    
    static struct ast_format_def wav16_f = {
    
    	.name = "wav16",
    	.exts = "wav16",
    
    	.mime_types = "audio/x-wav;codec=pcm;bit=16;rate=16000",
    
    	.open =	wav_open,
    	.rewrite = wav_rewrite,
    	.write = wav_write,
    	.seek = wav_seek,
    	.trunc = wav_trunc,
    	.tell =	wav_tell,
    	.read = wav_read,
    	.close = wav_close,
    	.buf_size = (WAV_BUF_SIZE * 2) + AST_FRIENDLY_OFFSET,
    	.desc_size = sizeof(struct wav_desc),
    };
    
    
    static struct ast_format_def wav_f = {
    
    	.name = "wav",
    	.exts = "wav",
    
    	.mime_types = "audio/wav|audio/x-wav|audio/x-wav;codec=pcm;bit=16;rate=8000",
    
    	.open =	wav_open,
    	.rewrite = wav_rewrite,
    	.write = wav_write,
    	.seek = wav_seek,
    	.trunc = wav_trunc,
    	.tell =	wav_tell,
    	.read = wav_read,
    	.close = wav_close,
    	.buf_size = WAV_BUF_SIZE + AST_FRIENDLY_OFFSET,
    	.desc_size = sizeof(struct wav_desc),
    };
    
    static int unload_module(void)
    {
    	return ast_format_def_unregister(wav_f.name)
    		|| ast_format_def_unregister(wav16_f.name);
    }
    
    
    static int load_module(void)
    
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    {
    
    	wav_f.format = ast_format_slin;
    	wav16_f.format = ast_format_slin16;
    
    	if (ast_format_def_register(&wav_f)
    
    		|| ast_format_def_register(&wav16_f)) {
    		unload_module();
    		return AST_MODULE_LOAD_DECLINE;
    	}
    
    	return AST_MODULE_LOAD_SUCCESS;
    
    AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "Microsoft WAV/WAV16 format (8kHz/16kHz Signed Linear)",
    
    	.load = load_module,
    	.unload = unload_module,
    	.load_pri = AST_MODPRI_APP_DEPEND
    );