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  •  * Asterisk -- An open source telephony toolkit.
    
     * Copyright (C) 1999 - 2005, Anthony Minessale
    
     * Anthony Minessale (anthmct@yahoo.com)
     *
    
     * 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.
     *
    
     * 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 RAW SLINEAR Format
    
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     * \arg File name extensions: sln, raw
     * \ingroup formats
    
    #include "asterisk.h"
    
    ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
    
    
    #include "asterisk/mod_format.h"
    
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    #include "asterisk/module.h"
    #include "asterisk/endian.h"
    
    
    #define BUF_SIZE	320		/* 320 bytes, 160 samples */
    #define	SLIN_SAMPLES	160
    
    
    static struct ast_frame *slinear_read(struct ast_filestream *s, int *whennext)
    {
    	int res;
    	/* Send a frame from the file to the appropriate channel */
    
    	s->fr.frametype = AST_FRAME_VOICE;
    
    	s->fr.subclass.codec = AST_FORMAT_SLINEAR;
    
    	s->fr.mallocd = 0;
    
    	AST_FRAME_SET_BUFFER(&s->fr, s->buf, AST_FRIENDLY_OFFSET, BUF_SIZE);
    
    	if ((res = fread(s->fr.data.ptr, 1, s->fr.datalen, s->f)) < 1) {
    
    		if (res)
    			ast_log(LOG_WARNING, "Short read (%d) (%s)!\n", res, strerror(errno));
    		return NULL;
    	}
    
    	*whennext = s->fr.samples = res/2;
    
    	s->fr.datalen = res;
    	return &s->fr;
    }
    
    static int slinear_write(struct ast_filestream *fs, struct ast_frame *f)
    {
    	int res;
    	if (f->frametype != AST_FRAME_VOICE) {
    		ast_log(LOG_WARNING, "Asked to write non-voice frame!\n");
    		return -1;
    	}
    
    	if (f->subclass.codec != AST_FORMAT_SLINEAR) {
    		ast_log(LOG_WARNING, "Asked to write non-slinear frame (%s)!\n", ast_getformatname(f->subclass.codec));
    
    	if ((res = fwrite(f->data.ptr, 1, f->datalen, fs->f)) != f->datalen) {
    
    			ast_log(LOG_WARNING, "Bad write (%d/%d): %s\n", res, f->datalen, strerror(errno));
    			return -1;
    	}
    	return 0;
    }
    
    
    static int slinear_seek(struct ast_filestream *fs, off_t sample_offset, int whence)
    
    {
    	off_t offset=0,min,cur,max;
    
    	min = 0;
    
    	sample_offset <<= 1;
    
    	cur = ftello(fs->f);
    	fseeko(fs->f, 0, SEEK_END);
    	max = ftello(fs->f);
    
    	if (whence == SEEK_SET)
    		offset = sample_offset;
    	else if (whence == SEEK_CUR || whence == SEEK_FORCECUR)
    		offset = sample_offset + cur;
    	else if (whence == SEEK_END)
    		offset = max - sample_offset;
    	if (whence != SEEK_FORCECUR) {
    		offset = (offset > max)?max:offset;
    	}
    
    	/* always protect against seeking past begining. */
    
    	offset = (offset < min)?min:offset;
    
    	return fseeko(fs->f, offset, SEEK_SET);
    
    }
    
    static int slinear_trunc(struct ast_filestream *fs)
    {
    
    	return ftruncate(fileno(fs->f), ftello(fs->f));
    
    static off_t slinear_tell(struct ast_filestream *fs)
    
    	return ftello(fs->f) / 2;
    
    static const struct ast_format slin_f = {
    	.name = "sln",
    	.exts = "sln|raw",
    	.format = AST_FORMAT_SLINEAR,
    	.write = slinear_write,
    	.seek = slinear_seek,
    	.trunc = slinear_trunc,
    	.tell = slinear_tell,
    	.read = slinear_read,
    	.buf_size = BUF_SIZE + AST_FRIENDLY_OFFSET,
    };
    
    static int load_module(void)
    
    	if (ast_format_register(&slin_f))
    		return AST_MODULE_LOAD_FAILURE;
    	return AST_MODULE_LOAD_SUCCESS;
    
    static int unload_module(void)
    
    	return ast_format_unregister(slin_f.name);
    
    AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "Raw Signed Linear Audio support (SLN)",
    	.load = load_module,
    	.unload = unload_module,
    	.load_pri = 10,
    );