Wed Apr 6 11:30:04 2011

Asterisk developer's documentation


format_gsm.c File Reference

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

#include "asterisk.h"
#include "asterisk/mod_format.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_ORDER , .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 = "8586c2a7d357cb591cc3a6607a8f62d1" , .load = load_module, .unload = unload_module, .load_pri = AST_MODPRI_APP_DEPEND }
static struct ast_module_infoast_module_info = &__mod_info
static struct ast_format gsm_f
static const 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 40 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 41 of file format_gsm.c.


Function Documentation

static void __reg_module ( void   )  [static]

Definition at line 176 of file format_gsm.c.

static void __unreg_module ( void   )  [static]

Definition at line 176 of file format_gsm.c.

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

Definition at line 51 of file format_gsm.c.

References AST_FORMAT_GSM, AST_FRAME_SET_BUFFER, AST_FRAME_VOICE, AST_FRIENDLY_OFFSET, ast_log(), ast_filestream::buf, ast_frame_subclass::codec, ast_frame::data, errno, ast_filestream::f, ast_filestream::fr, ast_frame::frametype, GSM_FRAME_SIZE, GSM_SAMPLES, LOG_WARNING, ast_frame::mallocd, ast_frame::ptr, ast_frame::samples, and ast_frame::subclass.

00052 {
00053    int res;
00054 
00055    s->fr.frametype = AST_FRAME_VOICE;
00056    s->fr.subclass.codec = AST_FORMAT_GSM;
00057    AST_FRAME_SET_BUFFER(&(s->fr), s->buf, AST_FRIENDLY_OFFSET, GSM_FRAME_SIZE)
00058    s->fr.mallocd = 0;
00059    if ((res = fread(s->fr.data.ptr, 1, GSM_FRAME_SIZE, s->f)) != GSM_FRAME_SIZE) {
00060       if (res)
00061          ast_log(LOG_WARNING, "Short read (%d) (%s)!\n", res, strerror(errno));
00062       return NULL;
00063    }
00064    *whennext = s->fr.samples = GSM_SAMPLES;
00065    return &s->fr;
00066 }

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

Definition at line 105 of file format_gsm.c.

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

00106 {
00107    off_t offset=0,min,cur,max,distance;
00108    
00109    min = 0;
00110    cur = ftello(fs->f);
00111    fseeko(fs->f, 0, SEEK_END);
00112    max = ftello(fs->f);
00113    /* have to fudge to frame here, so not fully to sample */
00114    distance = (sample_offset/GSM_SAMPLES) * GSM_FRAME_SIZE;
00115    if(whence == SEEK_SET)
00116       offset = distance;
00117    else if(whence == SEEK_CUR || whence == SEEK_FORCECUR)
00118       offset = distance + cur;
00119    else if(whence == SEEK_END)
00120       offset = max - distance;
00121    /* Always protect against seeking past the begining. */
00122    offset = (offset < min)?min:offset;
00123    if (whence != SEEK_FORCECUR) {
00124       offset = (offset > max)?max:offset;
00125    } else if (offset > max) {
00126       int i;
00127       fseeko(fs->f, 0, SEEK_END);
00128       for (i=0; i< (offset - max) / GSM_FRAME_SIZE; i++) {
00129          if (!fwrite(gsm_silence, 1, GSM_FRAME_SIZE, fs->f)) {
00130             ast_log(LOG_WARNING, "fwrite() failed: %s\n", strerror(errno));
00131          }
00132       }
00133    }
00134    return fseeko(fs->f, offset, SEEK_SET);
00135 }

static off_t gsm_tell ( struct ast_filestream fs  )  [static]

Definition at line 142 of file format_gsm.c.

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

00143 {
00144    off_t offset = ftello(fs->f);
00145    return (offset/GSM_FRAME_SIZE)*GSM_SAMPLES;
00146 }

static int gsm_trunc ( struct ast_filestream fs  )  [static]

Definition at line 137 of file format_gsm.c.

References ast_filestream::f.

00138 {
00139    return ftruncate(fileno(fs->f), ftello(fs->f));
00140 }

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

Definition at line 68 of file format_gsm.c.

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

00069 {
00070    int res;
00071    unsigned char gsm[2*GSM_FRAME_SIZE];
00072 
00073    if (f->frametype != AST_FRAME_VOICE) {
00074       ast_log(LOG_WARNING, "Asked to write non-voice frame!\n");
00075       return -1;
00076    }
00077    if (f->subclass.codec != AST_FORMAT_GSM) {
00078       ast_log(LOG_WARNING, "Asked to write non-GSM frame (%s)!\n", ast_getformatname(f->subclass.codec));
00079       return -1;
00080    }
00081    if (!(f->datalen % 65)) {
00082       /* This is in MSGSM format, need to be converted */
00083       int len=0;
00084       while(len < f->datalen) {
00085          conv65(f->data.ptr + len, gsm);
00086          if ((res = fwrite(gsm, 1, 2*GSM_FRAME_SIZE, fs->f)) != 2*GSM_FRAME_SIZE) {
00087             ast_log(LOG_WARNING, "Bad write (%d/66): %s\n", res, strerror(errno));
00088             return -1;
00089          }
00090          len += 65;
00091       }
00092    } else {
00093       if (f->datalen % GSM_FRAME_SIZE) {
00094          ast_log(LOG_WARNING, "Invalid data length, %d, should be multiple of 33\n", f->datalen);
00095          return -1;
00096       }
00097       if ((res = fwrite(f->data.ptr, 1, f->datalen, fs->f)) != f->datalen) {
00098             ast_log(LOG_WARNING, "Bad write (%d/33): %s\n", res, strerror(errno));
00099             return -1;
00100       }
00101    }
00102    return 0;
00103 }

static int load_module ( void   )  [static]

Definition at line 160 of file format_gsm.c.

References ast_format_register, AST_MODULE_LOAD_FAILURE, AST_MODULE_LOAD_SUCCESS, and gsm_f.

00161 {
00162    if (ast_format_register(&gsm_f))
00163       return AST_MODULE_LOAD_FAILURE;
00164    return AST_MODULE_LOAD_SUCCESS;
00165 }

static int unload_module ( void   )  [static]

Definition at line 167 of file format_gsm.c.

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

00168 {
00169    return ast_format_unregister(gsm_f.name);
00170 }


Variable Documentation

struct ast_module_info __mod_info = { .name = AST_MODULE, .flags = AST_MODFLAG_LOAD_ORDER , .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 = "8586c2a7d357cb591cc3a6607a8f62d1" , .load = load_module, .unload = unload_module, .load_pri = AST_MODPRI_APP_DEPEND } [static]

Definition at line 176 of file format_gsm.c.

struct ast_module_info* ast_module_info = &__mod_info [static]

Definition at line 176 of file format_gsm.c.

struct ast_format gsm_f [static]

Definition at line 148 of file format_gsm.c.

Referenced by load_module(), and unload_module().

const char gsm_silence[] [static]

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 45 of file format_gsm.c.


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