Sat Aug 6 00:39:56 2011

Asterisk developer's documentation


format_gsm.c File Reference

Save to raw, headerless GSM data. More...

#include "asterisk.h"
#include <unistd.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <sys/time.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include "asterisk/lock.h"
#include "asterisk/channel.h"
#include "asterisk/file.h"
#include "asterisk/logger.h"
#include "asterisk/sched.h"
#include "asterisk/module.h"
#include "asterisk/endian.h"
#include "msgsm.h"

Go to the source code of this file.

Defines

#define GSM_FRAME_SIZE   33
#define GSM_SAMPLES   160

Functions

static void __reg_module (void)
static void __unreg_module (void)
static struct ast_framegsm_read (struct ast_filestream *s, int *whennext)
static int gsm_seek (struct ast_filestream *fs, off_t sample_offset, int whence)
static off_t gsm_tell (struct ast_filestream *fs)
static int gsm_trunc (struct ast_filestream *fs)
static int gsm_write (struct ast_filestream *fs, struct ast_frame *f)
static int load_module (void)
static int unload_module (void)

Variables

static struct ast_module_info __mod_info = { .name = AST_MODULE, .flags = AST_MODFLAG_LOAD_FIRST | AST_MODFLAG_BUILDSUM, .description = "Raw GSM data" , .key = "This paragraph is copyright (c) 2006 by Digium, Inc. \In order for your module to load, it must return this \key via a function called \"key\". Any code which \includes this paragraph must be licensed under the GNU \General Public License version 2 or later (at your \option). In addition to Digium's general reservations \of rights, Digium expressly reserves the right to \allow other parties to license this paragraph under \different terms. Any use of Digium, Inc. trademarks or \logos (including \"Asterisk\" or \"Digium\") without \express written permission of Digium, Inc. is prohibited.\n" , .buildopt_sum = "361d7bb937402d51e4658efb5b4d76e4" , .load = load_module, .unload = unload_module, }
static const struct ast_module_infoast_module_info = &__mod_info
static struct ast_format gsm_f
char gsm_silence []


Detailed Description

Save to raw, headerless GSM data.

Definition in file format_gsm.c.


Define Documentation

#define GSM_FRAME_SIZE   33

Definition at line 53 of file format_gsm.c.

Referenced by gsm_read(), gsm_seek(), gsm_tell(), gsm_write(), wav_read(), and wav_write().

#define GSM_SAMPLES   160

Definition at line 54 of file format_gsm.c.


Function Documentation

static void __reg_module ( void   )  [static]

Definition at line 186 of file format_gsm.c.

static void __unreg_module ( void   )  [static]

Definition at line 186 of file format_gsm.c.

static struct ast_frame* gsm_read ( struct ast_filestream s,
int *  whennext 
) [static]

Definition at line 64 of file format_gsm.c.

References AST_FORMAT_GSM, AST_FRAME_SET_BUFFER, AST_FRAME_VOICE, AST_FRIENDLY_OFFSET, ast_log(), errno, GSM_FRAME_SIZE, GSM_SAMPLES, LOG_WARNING, and s.

00065 {
00066    int res;
00067 
00068    s->fr.frametype = AST_FRAME_VOICE;
00069    s->fr.subclass = AST_FORMAT_GSM;
00070    AST_FRAME_SET_BUFFER(&(s->fr), s->buf, AST_FRIENDLY_OFFSET, GSM_FRAME_SIZE)
00071    s->fr.mallocd = 0;
00072    if ((res = fread(s->fr.data, 1, GSM_FRAME_SIZE, s->f)) != GSM_FRAME_SIZE) {
00073       if (res)
00074          ast_log(LOG_WARNING, "Short read (%d) (%s)!\n", res, strerror(errno));
00075       return NULL;
00076    }
00077    *whennext = s->fr.samples = GSM_SAMPLES;
00078    return &s->fr;
00079 }

static int gsm_seek ( struct ast_filestream fs,
off_t  sample_offset,
int  whence 
) [static]

Definition at line 118 of file format_gsm.c.

References ast_log(), errno, ast_filestream::f, GSM_FRAME_SIZE, GSM_SAMPLES, LOG_WARNING, offset, and SEEK_FORCECUR.

00119 {
00120    off_t offset=0,min,cur,max,distance;
00121    
00122    min = 0;
00123    cur = ftello(fs->f);
00124    fseeko(fs->f, 0, SEEK_END);
00125    max = ftello(fs->f);
00126    /* have to fudge to frame here, so not fully to sample */
00127    distance = (sample_offset/GSM_SAMPLES) * GSM_FRAME_SIZE;
00128    if(whence == SEEK_SET)
00129       offset = distance;
00130    else if(whence == SEEK_CUR || whence == SEEK_FORCECUR)
00131       offset = distance + cur;
00132    else if(whence == SEEK_END)
00133       offset = max - distance;
00134    /* Always protect against seeking past the begining. */
00135    offset = (offset < min)?min:offset;
00136    if (whence != SEEK_FORCECUR) {
00137       offset = (offset > max)?max:offset;
00138    } else if (offset > max) {
00139       int i;
00140       fseeko(fs->f, 0, SEEK_END);
00141       for (i=0; i< (offset - max) / GSM_FRAME_SIZE; i++) {
00142          if (!fwrite(gsm_silence, 1, GSM_FRAME_SIZE, fs->f)) {
00143             ast_log(LOG_WARNING, "fwrite() failed: %s\n", strerror(errno));
00144          }
00145       }
00146    }
00147    return fseeko(fs->f, offset, SEEK_SET);
00148 }

static off_t gsm_tell ( struct ast_filestream fs  )  [static]

Definition at line 155 of file format_gsm.c.

References ast_filestream::f, GSM_FRAME_SIZE, GSM_SAMPLES, and offset.

00156 {
00157    off_t offset = ftello(fs->f);
00158    return (offset/GSM_FRAME_SIZE)*GSM_SAMPLES;
00159 }

static int gsm_trunc ( struct ast_filestream fs  )  [static]

Definition at line 150 of file format_gsm.c.

References ast_filestream::f.

00151 {
00152    return ftruncate(fileno(fs->f), ftello(fs->f));
00153 }

static int gsm_write ( struct ast_filestream fs,
struct ast_frame f 
) [static]

Definition at line 81 of file format_gsm.c.

References AST_FORMAT_GSM, AST_FRAME_VOICE, ast_log(), conv65(), ast_frame::datalen, errno, ast_filestream::f, f, GSM_FRAME_SIZE, len(), and LOG_WARNING.

00082 {
00083    int res;
00084    unsigned char gsm[2*GSM_FRAME_SIZE];
00085 
00086    if (f->frametype != AST_FRAME_VOICE) {
00087       ast_log(LOG_WARNING, "Asked to write non-voice frame!\n");
00088       return -1;
00089    }
00090    if (f->subclass != AST_FORMAT_GSM) {
00091       ast_log(LOG_WARNING, "Asked to write non-GSM frame (%d)!\n", f->subclass);
00092       return -1;
00093    }
00094    if (!(f->datalen % 65)) {
00095       /* This is in MSGSM format, need to be converted */
00096       int len=0;
00097       while(len < f->datalen) {
00098          conv65(f->data + len, gsm);
00099          if ((res = fwrite(gsm, 1, 2*GSM_FRAME_SIZE, fs->f)) != 2*GSM_FRAME_SIZE) {
00100             ast_log(LOG_WARNING, "Bad write (%d/66): %s\n", res, strerror(errno));
00101             return -1;
00102          }
00103          len += 65;
00104       }
00105    } else {
00106       if (f->datalen % GSM_FRAME_SIZE) {
00107          ast_log(LOG_WARNING, "Invalid data length, %d, should be multiple of 33\n", f->datalen);
00108          return -1;
00109       }
00110       if ((res = fwrite(f->data, 1, f->datalen, fs->f)) != f->datalen) {
00111             ast_log(LOG_WARNING, "Bad write (%d/33): %s\n", res, strerror(errno));
00112             return -1;
00113       }
00114    }
00115    return 0;
00116 }

static int load_module ( void   )  [static]

Definition at line 173 of file format_gsm.c.

References ast_format_register, and gsm_f.

00174 {
00175    return ast_format_register(&gsm_f);
00176 }

static int unload_module ( void   )  [static]

Definition at line 178 of file format_gsm.c.

References ast_format_unregister(), gsm_f, and ast_format::name.

00179 {
00180    return ast_format_unregister(gsm_f.name);
00181 }  


Variable Documentation

struct ast_module_info __mod_info = { .name = AST_MODULE, .flags = AST_MODFLAG_LOAD_FIRST | AST_MODFLAG_BUILDSUM, .description = "Raw GSM data" , .key = "This paragraph is copyright (c) 2006 by Digium, Inc. \In order for your module to load, it must return this \key via a function called \"key\". Any code which \includes this paragraph must be licensed under the GNU \General Public License version 2 or later (at your \option). In addition to Digium's general reservations \of rights, Digium expressly reserves the right to \allow other parties to license this paragraph under \different terms. Any use of Digium, Inc. trademarks or \logos (including \"Asterisk\" or \"Digium\") without \express written permission of Digium, Inc. is prohibited.\n" , .buildopt_sum = "361d7bb937402d51e4658efb5b4d76e4" , .load = load_module, .unload = unload_module, } [static]

Definition at line 186 of file format_gsm.c.

const struct ast_module_info* ast_module_info = &__mod_info [static]

Definition at line 186 of file format_gsm.c.

struct ast_format gsm_f [static]

Definition at line 161 of file format_gsm.c.

Referenced by load_module(), and unload_module().

char gsm_silence[]

Initial value:

 
{0xD8,0x20,0xA2,0xE1,0x5A,0x50,0x00,0x49,0x24,0x92,0x49,0x24,0x50,0x00,0x49
,0x24,0x92,0x49,0x24,0x50,0x00,0x49,0x24,0x92,0x49,0x24,0x50,0x00,0x49,0x24
,0x92,0x49,0x24}

Definition at line 58 of file format_gsm.c.


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