format_ilbc.c

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00001 /*
00002  * Asterisk -- An open source telephony toolkit.
00003  *
00004  * Brian K. West <brian@bkw.org>
00005  * 
00006  * Copyright (C) 1999 - 2005, Digium, Inc.
00007  *
00008  * Mark Spencer <markster@digium.com>
00009  *
00010  * See http://www.asterisk.org for more information about
00011  * the Asterisk project. Please do not directly contact
00012  * any of the maintainers of this project for assistance;
00013  * the project provides a web site, mailing lists and IRC
00014  * channels for your use.
00015  *
00016  * This program is free software, distributed under the terms of
00017  * the GNU General Public License Version 2. See the LICENSE file
00018  * at the top of the source tree.
00019  */
00020 
00021 /*! \file
00022  *
00023  * \brief Save to raw, headerless iLBC data.
00024  * \arg File name extension: ilbc
00025  * \ingroup formats
00026  */
00027 
00028 /*** MODULEINFO
00029    <support_level>core</support_level>
00030  ***/
00031 
00032 #include "asterisk.h"
00033 
00034 ASTERISK_FILE_VERSION(__FILE__, "$Revision: 419592 $")
00035 
00036 #include "asterisk/mod_format.h"
00037 #include "asterisk/module.h"
00038 #include "asterisk/endian.h"
00039 #include "asterisk/format_cache.h"
00040 
00041 /* Some Ideas for this code came from makeg729e.c by Jeffrey Chilton */
00042 
00043 /* Portions of the conversion code are by guido@sienanet.it */
00044 
00045 #define  ILBC_BUF_SIZE  50 /* One Real iLBC Frame */
00046 #define  ILBC_SAMPLES   240
00047 
00048 static struct ast_frame *ilbc_read(struct ast_filestream *s, int *whennext)
00049 {
00050    int res;
00051    /* Send a frame from the file to the appropriate channel */
00052    AST_FRAME_SET_BUFFER(&s->fr, s->buf, AST_FRIENDLY_OFFSET, ILBC_BUF_SIZE);
00053    if ((res = fread(s->fr.data.ptr, 1, s->fr.datalen, s->f)) != s->fr.datalen) {
00054       if (res)
00055          ast_log(LOG_WARNING, "Short read (%d) (%s)!\n", res, strerror(errno));
00056       return NULL;
00057    }
00058    *whennext = s->fr.samples = ILBC_SAMPLES;
00059    return &s->fr;
00060 }
00061 
00062 static int ilbc_write(struct ast_filestream *fs, struct ast_frame *f)
00063 {
00064    int res;
00065    if (f->datalen % 50) {
00066       ast_log(LOG_WARNING, "Invalid data length, %d, should be multiple of 50\n", f->datalen);
00067       return -1;
00068    }
00069    if ((res = fwrite(f->data.ptr, 1, f->datalen, fs->f)) != f->datalen) {
00070          ast_log(LOG_WARNING, "Bad write (%d/50): %s\n", res, strerror(errno));
00071          return -1;
00072    }
00073    return 0;
00074 }
00075 
00076 static int ilbc_seek(struct ast_filestream *fs, off_t sample_offset, int whence)
00077 {
00078    long bytes;
00079    off_t min,cur,max,offset=0;
00080    min = 0;
00081    cur = ftello(fs->f);
00082    fseeko(fs->f, 0, SEEK_END);
00083    max = ftello(fs->f);
00084    
00085    bytes = ILBC_BUF_SIZE * (sample_offset / ILBC_SAMPLES);
00086    if (whence == SEEK_SET)
00087       offset = bytes;
00088    else if (whence == SEEK_CUR || whence == SEEK_FORCECUR)
00089       offset = cur + bytes;
00090    else if (whence == SEEK_END)
00091       offset = max - bytes;
00092    if (whence != SEEK_FORCECUR) {
00093       offset = (offset > max)?max:offset;
00094    }
00095    /* protect against seeking beyond begining. */
00096    offset = (offset < min)?min:offset;
00097    if (fseeko(fs->f, offset, SEEK_SET) < 0)
00098       return -1;
00099    return 0;
00100 }
00101 
00102 static int ilbc_trunc(struct ast_filestream *fs)
00103 {
00104    int fd;
00105    off_t cur;
00106 
00107    if ((fd = fileno(fs->f)) < 0) {
00108       ast_log(AST_LOG_WARNING, "Unable to determine file descriptor for iLBC filestream %p: %s\n", fs, strerror(errno));
00109       return -1;
00110    }
00111    if ((cur = ftello(fs->f)) < 0) {
00112       ast_log(AST_LOG_WARNING, "Unable to determine current position in iLBC filestream %p: %s\n", fs, strerror(errno));
00113       return -1;
00114    }
00115    /* Truncate file to current length */
00116    return ftruncate(fd, cur);
00117 }
00118 
00119 static off_t ilbc_tell(struct ast_filestream *fs)
00120 {
00121    off_t offset = ftello(fs->f);
00122    return (offset/ILBC_BUF_SIZE)*ILBC_SAMPLES;
00123 }
00124 
00125 static struct ast_format_def ilbc_f = {
00126    .name = "iLBC",
00127    .exts = "ilbc",
00128    .write = ilbc_write,
00129    .seek = ilbc_seek,
00130    .trunc = ilbc_trunc,
00131    .tell = ilbc_tell,
00132    .read = ilbc_read,
00133    .buf_size = ILBC_BUF_SIZE + AST_FRIENDLY_OFFSET,
00134 };
00135 
00136 static int load_module(void)
00137 {
00138    ilbc_f.format = ast_format_ilbc;
00139    if (ast_format_def_register(&ilbc_f))
00140       return AST_MODULE_LOAD_FAILURE;
00141    return AST_MODULE_LOAD_SUCCESS;
00142 }
00143 
00144 static int unload_module(void)
00145 {
00146    return ast_format_def_unregister(ilbc_f.name);
00147 }
00148 
00149 AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "Raw iLBC data",
00150    .support_level = AST_MODULE_SUPPORT_CORE,
00151    .load = load_module,
00152    .unload = unload_module,
00153    .load_pri = AST_MODPRI_APP_DEPEND
00154 );

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