formats/format_gsm.c

   1 /*
   2  * Asterisk -- An open source telephony toolkit.
   3  *
   4  * Copyright (C) 1999 - 2005, Digium, Inc.
   5  *
   6  * Mark Spencer <markster@digium.com>
   7  *
   8  * See http://www.asterisk.org for more information about
   9  * the Asterisk project. Please do not directly contact
  10  * any of the maintainers of this project for assistance;
  11  * the project provides a web site, mailing lists and IRC
  12  * channels for your use.
  13  *
  14  * This program is free software, distributed under the terms of
  15  * the GNU General Public License Version 2. See the LICENSE file
  16  * at the top of the source tree.
  17  */
  18
  19 /*! \file
  20  *
  21  * \brief Save to raw, headerless GSM data.
  22  * \arg File name extension: gsm
  23  * \ingroup formats
  24  */
  25
  26 #include "asterisk.h"
  27
  28 ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
  29
  30 #include <unistd.h>
  31 #include <netinet/in.h>
  32 #include <arpa/inet.h>
  33 #include <stdlib.h>
  34 #include <sys/time.h>
  35 #include <stdio.h>
  36 #include <errno.h>
  37 #include <string.h>
  38
  39 #include "asterisk/lock.h"
  40 #include "asterisk/channel.h"
  41 #include "asterisk/file.h"
  42 #include "asterisk/logger.h"
  43 #include "asterisk/sched.h"
  44 #include "asterisk/module.h"
  45 #include "asterisk/endian.h"
  46
  47 #include "msgsm.h"
  48
  49 /* Some Ideas for this code came from makegsme.c by Jeffrey Chilton */
  50
  51 /* Portions of the conversion code are by guido@sienanet.it */
  52
  53 #define GSM_FRAME_SIZE  33
  54 #define GSM_SAMPLES     160
  55
  56 /* silent gsm frame */
  57 /* begin binary data: */
  58 char gsm_silence[] = /* 33 */
  59 {0xD8,0x20,0xA2,0xE1,0x5A,0x50,0x00,0x49,0x24,0x92,0x49,0x24,0x50,0x00,0x49
  60 ,0x24,0x92,0x49,0x24,0x50,0x00,0x49,0x24,0x92,0x49,0x24,0x50,0x00,0x49,0x24
  61 ,0x92,0x49,0x24};
  62 /* end binary data. size = 33 bytes */
  63
  64 static struct ast_frame *gsm_read(struct ast_filestream *s, int *whennext)
  65 {
  66         int res;
  67
  68         s->fr.frametype = AST_FRAME_VOICE;
  69         s->fr.subclass = AST_FORMAT_GSM;
  70         AST_FRAME_SET_BUFFER(&(s->fr), s->buf, AST_FRIENDLY_OFFSET, GSM_FRAME_SIZE)
  71         s->fr.mallocd = 0;
  72         if ((res = fread(s->fr.data, 1, GSM_FRAME_SIZE, s->f)) != GSM_FRAME_SIZE) {
  73                 if (res)
  74                         ast_log(LOG_WARNING, "Short read (%d) (%s)!\n", res, strerror(errno));
  75                 return NULL;
  76         }
  77         *whennext = s->fr.samples = GSM_SAMPLES;
  78         return &s->fr;
  79 }
  80
  81 static int gsm_write(struct ast_filestream *fs, struct ast_frame *f)
  82 {
  83         int res;
  84         unsigned char gsm[2*GSM_FRAME_SIZE];
  85
  86         if (f->frametype != AST_FRAME_VOICE) {
  87                 ast_log(LOG_WARNING, "Asked to write non-voice frame!\n");
  88                 return -1;
  89         }
  90         if (f->subclass != AST_FORMAT_GSM) {
  91                 ast_log(LOG_WARNING, "Asked to write non-GSM frame (%d)!\n", f->subclass);
  92                 return -1;
  93         }
  94         if (!(f->datalen % 65)) {
  95                 /* This is in MSGSM format, need to be converted */
  96                 int len=0;
  97                 while(len < f->datalen) {
  98                         conv65(f->data + len, gsm);
  99                         if ((res = fwrite(gsm, 1, 2*GSM_FRAME_SIZE, fs->f)) != 2*GSM_FRAME_SIZE) {
 100                                 ast_log(LOG_WARNING, "Bad write (%d/66): %s\n", res, strerror(errno));
 101                                 return -1;
 102                         }
 103                         len += 65;
 104                 }
 105         } else {
 106                 if (f->datalen % GSM_FRAME_SIZE) {
 107                         ast_log(LOG_WARNING, "Invalid data length, %d, should be multiple of 33\n", f->datalen);
 108                         return -1;
 109                 }
 110                 if ((res = fwrite(f->data, 1, f->datalen, fs->f)) != f->datalen) {
 111                                 ast_log(LOG_WARNING, "Bad write (%d/33): %s\n", res, strerror(errno));
 112                                 return -1;
 113                 }
 114         }
 115         return 0;
 116 }
 117
 118 static int gsm_seek(struct ast_filestream *fs, off_t sample_offset, int whence)
 119 {
 120         off_t offset=0,min,cur,max,distance;
 121
 122         min = 0;
 123         cur = ftello(fs->f);
 124         fseeko(fs->f, 0, SEEK_END);
 125         max = ftello(fs->f);
 126         /* have to fudge to frame here, so not fully to sample */
 127         distance = (sample_offset/GSM_SAMPLES) * GSM_FRAME_SIZE;
 128         if(whence == SEEK_SET)
 129                 offset = distance;
 130         else if(whence == SEEK_CUR || whence == SEEK_FORCECUR)
 131                 offset = distance + cur;
 132         else if(whence == SEEK_END)
 133                 offset = max - distance;
 134         /* Always protect against seeking past the begining. */
 135         offset = (offset < min)?min:offset;
 136         if (whence != SEEK_FORCECUR) {
 137                 offset = (offset > max)?max:offset;
 138         } else if (offset > max) {
 139                 int i;
 140                 fseeko(fs->f, 0, SEEK_END);
 141                 for (i=0; i< (offset - max) / GSM_FRAME_SIZE; i++) {
 142                         fwrite(gsm_silence, 1, GSM_FRAME_SIZE, fs->f);
 143                 }
 144         }
 145         return fseeko(fs->f, offset, SEEK_SET);
 146 }
 147
 148 static int gsm_trunc(struct ast_filestream *fs)
 149 {
 150         return ftruncate(fileno(fs->f), ftello(fs->f));
 151 }
 152
 153 static off_t gsm_tell(struct ast_filestream *fs)
 154 {
 155         off_t offset = ftello(fs->f);
 156         return (offset/GSM_FRAME_SIZE)*GSM_SAMPLES;
 157 }
 158
 159 static const struct ast_format gsm_f = {
 160         .name = "gsm",
 161         .exts = "gsm",
 162         .format = AST_FORMAT_GSM,
 163         .write = gsm_write,
 164         .seek = gsm_seek,
 165         .trunc = gsm_trunc,
 166         .tell = gsm_tell,
 167         .read = gsm_read,
 168         .buf_size = 2*GSM_FRAME_SIZE + AST_FRIENDLY_OFFSET,     /* 2 gsm frames */
 169 };
 170
 171 static int load_module(void)
 172 {
 173         return ast_format_register(&gsm_f);
 174 }
 175
 176 static int unload_module(void)
 177 {
 178         return ast_format_unregister(gsm_f.name);
 179 }
 180
 181 AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Raw GSM data");