Sat Mar 24 23:26:04 2007

Asterisk developer's documentation


format_ilbc.c

Go to the documentation of this file.
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 #include <unistd.h>
00029 #include <netinet/in.h>
00030 #include <arpa/inet.h>
00031 #include <stdlib.h>
00032 #include <sys/time.h>
00033 #include <stdio.h>
00034 #include <errno.h>
00035 #include <string.h>
00036 
00037 #include "asterisk.h"
00038 
00039 ASTERISK_FILE_VERSION(__FILE__, "$Revision: 7221 $")
00040 
00041 #include "asterisk/lock.h"
00042 #include "asterisk/channel.h"
00043 #include "asterisk/file.h"
00044 #include "asterisk/logger.h"
00045 #include "asterisk/sched.h"
00046 #include "asterisk/module.h"
00047 #include "asterisk/endian.h"
00048 
00049 /* Some Ideas for this code came from makeg729e.c by Jeffrey Chilton */
00050 
00051 /* Portions of the conversion code are by guido@sienanet.it */
00052 
00053 struct ast_filestream {
00054    void *reserved[AST_RESERVED_POINTERS];
00055    /* Believe it or not, we must decode/recode to account for the
00056       weird MS format */
00057    /* This is what a filestream means to us */
00058    FILE *f; /* Descriptor */
00059    struct ast_frame fr;          /* Frame information */
00060    char waste[AST_FRIENDLY_OFFSET]; /* Buffer for sending frames, etc */
00061    char empty;                   /* Empty character */
00062    unsigned char ilbc[50];          /* One Real iLBC Frame */
00063 };
00064 
00065 
00066 AST_MUTEX_DEFINE_STATIC(ilbc_lock);
00067 static int glistcnt = 0;
00068 
00069 static char *name = "iLBC";
00070 static char *desc = "Raw iLBC data";
00071 static char *exts = "ilbc";
00072 
00073 static struct ast_filestream *ilbc_open(FILE *f)
00074 {
00075    /* We don't have any header to read or anything really, but
00076       if we did, it would go here.  We also might want to check
00077       and be sure it's a valid file.  */
00078    struct ast_filestream *tmp;
00079    if ((tmp = malloc(sizeof(struct ast_filestream)))) {
00080       memset(tmp, 0, sizeof(struct ast_filestream));
00081       if (ast_mutex_lock(&ilbc_lock)) {
00082          ast_log(LOG_WARNING, "Unable to lock ilbc list\n");
00083          free(tmp);
00084          return NULL;
00085       }
00086       tmp->f = f;
00087       tmp->fr.data = tmp->ilbc;
00088       tmp->fr.frametype = AST_FRAME_VOICE;
00089       tmp->fr.subclass = AST_FORMAT_ILBC;
00090       /* datalen will vary for each frame */
00091       tmp->fr.src = name;
00092       tmp->fr.mallocd = 0;
00093       glistcnt++;
00094       ast_mutex_unlock(&ilbc_lock);
00095       ast_update_use_count();
00096    }
00097    return tmp;
00098 }
00099 
00100 static struct ast_filestream *ilbc_rewrite(FILE *f, const char *comment)
00101 {
00102    /* We don't have any header to read or anything really, but
00103       if we did, it would go here.  We also might want to check
00104       and be sure it's a valid file.  */
00105    struct ast_filestream *tmp;
00106    if ((tmp = malloc(sizeof(struct ast_filestream)))) {
00107       memset(tmp, 0, sizeof(struct ast_filestream));
00108       if (ast_mutex_lock(&ilbc_lock)) {
00109          ast_log(LOG_WARNING, "Unable to lock ilbc list\n");
00110          free(tmp);
00111          return NULL;
00112       }
00113       tmp->f = f;
00114       glistcnt++;
00115       ast_mutex_unlock(&ilbc_lock);
00116       ast_update_use_count();
00117    } else
00118       ast_log(LOG_WARNING, "Out of memory\n");
00119    return tmp;
00120 }
00121 
00122 static void ilbc_close(struct ast_filestream *s)
00123 {
00124    if (ast_mutex_lock(&ilbc_lock)) {
00125       ast_log(LOG_WARNING, "Unable to lock ilbc list\n");
00126       return;
00127    }
00128    glistcnt--;
00129    ast_mutex_unlock(&ilbc_lock);
00130    ast_update_use_count();
00131    fclose(s->f);
00132    free(s);
00133    s = NULL;
00134 }
00135 
00136 static struct ast_frame *ilbc_read(struct ast_filestream *s, int *whennext)
00137 {
00138    int res;
00139    /* Send a frame from the file to the appropriate channel */
00140    s->fr.frametype = AST_FRAME_VOICE;
00141    s->fr.subclass = AST_FORMAT_ILBC;
00142    s->fr.offset = AST_FRIENDLY_OFFSET;
00143    s->fr.samples = 240;
00144    s->fr.datalen = 50;
00145    s->fr.mallocd = 0;
00146    s->fr.data = s->ilbc;
00147    if ((res = fread(s->ilbc, 1, 50, s->f)) != 50) {
00148       if (res)
00149          ast_log(LOG_WARNING, "Short read (%d) (%s)!\n", res, strerror(errno));
00150       return NULL;
00151    }
00152    *whennext = s->fr.samples;
00153    return &s->fr;
00154 }
00155 
00156 static int ilbc_write(struct ast_filestream *fs, struct ast_frame *f)
00157 {
00158    int res;
00159    if (f->frametype != AST_FRAME_VOICE) {
00160       ast_log(LOG_WARNING, "Asked to write non-voice frame!\n");
00161       return -1;
00162    }
00163    if (f->subclass != AST_FORMAT_ILBC) {
00164       ast_log(LOG_WARNING, "Asked to write non-iLBC frame (%d)!\n", f->subclass);
00165       return -1;
00166    }
00167    if (f->datalen % 50) {
00168       ast_log(LOG_WARNING, "Invalid data length, %d, should be multiple of 50\n", f->datalen);
00169       return -1;
00170    }
00171    if ((res = fwrite(f->data, 1, f->datalen, fs->f)) != f->datalen) {
00172          ast_log(LOG_WARNING, "Bad write (%d/50): %s\n", res, strerror(errno));
00173          return -1;
00174    }
00175    return 0;
00176 }
00177 
00178 static char *ilbc_getcomment(struct ast_filestream *s)
00179 {
00180    return NULL;
00181 }
00182 
00183 static int ilbc_seek(struct ast_filestream *fs, long sample_offset, int whence)
00184 {
00185    long bytes;
00186    off_t min,cur,max,offset=0;
00187    min = 0;
00188    cur = ftell(fs->f);
00189    fseek(fs->f, 0, SEEK_END);
00190    max = ftell(fs->f);
00191    
00192    bytes = 50 * (sample_offset / 240);
00193    if (whence == SEEK_SET)
00194       offset = bytes;
00195    else if (whence == SEEK_CUR || whence == SEEK_FORCECUR)
00196       offset = cur + bytes;
00197    else if (whence == SEEK_END)
00198       offset = max - bytes;
00199    if (whence != SEEK_FORCECUR) {
00200       offset = (offset > max)?max:offset;
00201    }
00202    /* protect against seeking beyond begining. */
00203    offset = (offset < min)?min:offset;
00204    if (fseek(fs->f, offset, SEEK_SET) < 0)
00205       return -1;
00206    return 0;
00207 }
00208 
00209 static int ilbc_trunc(struct ast_filestream *fs)
00210 {
00211    /* Truncate file to current length */
00212    if (ftruncate(fileno(fs->f), ftell(fs->f)) < 0)
00213       return -1;
00214    return 0;
00215 }
00216 
00217 static long ilbc_tell(struct ast_filestream *fs)
00218 {
00219    off_t offset;
00220    offset = ftell(fs->f);
00221    return (offset/50)*240;
00222 }
00223 
00224 int load_module()
00225 {
00226    return ast_format_register(name, exts, AST_FORMAT_ILBC,
00227                         ilbc_open,
00228                         ilbc_rewrite,
00229                         ilbc_write,
00230                         ilbc_seek,
00231                         ilbc_trunc,
00232                         ilbc_tell,
00233                         ilbc_read,
00234                         ilbc_close,
00235                         ilbc_getcomment);
00236                         
00237                         
00238 }
00239 
00240 int unload_module()
00241 {
00242    return ast_format_unregister(name);
00243 }  
00244 
00245 int usecount()
00246 {
00247    return glistcnt;
00248 }
00249 
00250 char *description()
00251 {
00252    return desc;
00253 }
00254 
00255 
00256 char *key()
00257 {
00258    return ASTERISK_GPL_KEY;
00259 }

Generated on Sat Mar 24 23:26:04 2007 for Asterisk - the Open Source PBX by  doxygen 1.4.6