Thu Apr 28 2011 16:57:10

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"
Include dependency graph for format_gsm.c:

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
__MODULE_INFO_SECTION 
__mod_info = { __MODULE_INFO_GLOBALS .name = AST_MODULE, .flags = AST_MODFLAG_LOAD_ORDER , .description = "Raw GSM data" , .key = ASTERISK_GPL_KEY , .buildopt_sum = AST_BUILDOPT_SUM, .load = load_module, .unload = unload_module, .load_pri = 10, }
static 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.

  • File name extension: gsm

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(), and gsm_write().

#define GSM_SAMPLES   160

Definition at line 41 of file format_gsm.c.

Referenced by gsm_read(), gsm_seek(), and gsm_tell().


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, read]

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::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.

{
   int res;

   s->fr.frametype = AST_FRAME_VOICE;
   s->fr.subclass = AST_FORMAT_GSM;
   AST_FRAME_SET_BUFFER(&(s->fr), s->buf, AST_FRIENDLY_OFFSET, GSM_FRAME_SIZE)
   s->fr.mallocd = 0;
   if ((res = fread(s->fr.data.ptr, 1, GSM_FRAME_SIZE, s->f)) != GSM_FRAME_SIZE) {
      if (res)
         ast_log(LOG_WARNING, "Short read (%d) (%s)!\n", res, strerror(errno));
      return NULL;
   }
   *whennext = s->fr.samples = GSM_SAMPLES;
   return &s->fr;
}
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.

{
   off_t offset=0,min,cur,max,distance;
   
   min = 0;
   cur = ftello(fs->f);
   fseeko(fs->f, 0, SEEK_END);
   max = ftello(fs->f);
   /* have to fudge to frame here, so not fully to sample */
   distance = (sample_offset/GSM_SAMPLES) * GSM_FRAME_SIZE;
   if(whence == SEEK_SET)
      offset = distance;
   else if(whence == SEEK_CUR || whence == SEEK_FORCECUR)
      offset = distance + cur;
   else if(whence == SEEK_END)
      offset = max - distance;
   /* Always protect against seeking past the begining. */
   offset = (offset < min)?min:offset;
   if (whence != SEEK_FORCECUR) {
      offset = (offset > max)?max:offset;
   } else if (offset > max) {
      int i;
      fseeko(fs->f, 0, SEEK_END);
      for (i=0; i< (offset - max) / GSM_FRAME_SIZE; i++) {
         if (!fwrite(gsm_silence, 1, GSM_FRAME_SIZE, fs->f)) {
            ast_log(LOG_WARNING, "fwrite() failed: %s\n", strerror(errno));
         }
      }
   }
   return fseeko(fs->f, offset, SEEK_SET);
}
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.

{
   off_t offset = ftello(fs->f);
   return (offset/GSM_FRAME_SIZE)*GSM_SAMPLES;
}
static int gsm_trunc ( struct ast_filestream fs) [static]

Definition at line 137 of file format_gsm.c.

References ast_filestream::f.

{
   return ftruncate(fileno(fs->f), ftello(fs->f));
}
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_log(), conv65(), ast_frame::data, ast_frame::datalen, errno, ast_filestream::f, ast_frame::frametype, fwrite, GSM_FRAME_SIZE, len(), LOG_WARNING, ast_frame::ptr, and ast_frame::subclass.

{
   int res;
   unsigned char gsm[2*GSM_FRAME_SIZE];

   if (f->frametype != AST_FRAME_VOICE) {
      ast_log(LOG_WARNING, "Asked to write non-voice frame!\n");
      return -1;
   }
   if (f->subclass != AST_FORMAT_GSM) {
      ast_log(LOG_WARNING, "Asked to write non-GSM frame (%d)!\n", f->subclass);
      return -1;
   }
   if (!(f->datalen % 65)) {
      /* This is in MSGSM format, need to be converted */
      int len=0;
      while(len < f->datalen) {
         conv65(f->data.ptr + len, gsm);
         if ((res = fwrite(gsm, 1, 2*GSM_FRAME_SIZE, fs->f)) != 2*GSM_FRAME_SIZE) {
            ast_log(LOG_WARNING, "Bad write (%d/66): %s\n", res, strerror(errno));
            return -1;
         }
         len += 65;
      }
   } else {
      if (f->datalen % GSM_FRAME_SIZE) {
         ast_log(LOG_WARNING, "Invalid data length, %d, should be multiple of 33\n", f->datalen);
         return -1;
      }
      if ((res = fwrite(f->data.ptr, 1, f->datalen, fs->f)) != f->datalen) {
            ast_log(LOG_WARNING, "Bad write (%d/33): %s\n", res, strerror(errno));
            return -1;
      }
   }
   return 0;
}
static int load_module ( void  ) [static]
static int unload_module ( void  ) [static]

Definition at line 167 of file format_gsm.c.

References ast_format_unregister(), and ast_format::name.


Variable Documentation

struct ast_module_info __MODULE_INFO_SECTION __mod_info = { __MODULE_INFO_GLOBALS .name = AST_MODULE, .flags = AST_MODFLAG_LOAD_ORDER , .description = "Raw GSM data" , .key = ASTERISK_GPL_KEY , .buildopt_sum = AST_BUILDOPT_SUM, .load = load_module, .unload = unload_module, .load_pri = 10, } [static]

Definition at line 176 of file format_gsm.c.

Definition at line 176 of file format_gsm.c.

struct ast_format gsm_f [static]

Definition at line 148 of file format_gsm.c.

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 45 of file format_gsm.c.