Mon Mar 31 07:40:07 2008

Asterisk developer's documentation


codec_ulaw.c File Reference

codec_ulaw.c - translate between signed linear and ulaw More...

#include "asterisk.h"
#include <fcntl.h>
#include <netinet/in.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <spandsp/bit_operations.h>
#include <spandsp/g711.h>
#include "asterisk/lock.h"
#include "asterisk/logger.h"
#include "asterisk/module.h"
#include "asterisk/config.h"
#include "asterisk/options.h"
#include "asterisk/translate.h"
#include "asterisk/channel.h"
#include "asterisk/ulaw.h"
#include "asterisk/utils.h"
#include "slin_ulaw_ex.h"
#include "ulaw_slin_ex.h"

Include dependency graph for codec_ulaw.c:

Go to the source code of this file.

Defines

#define BUFFER_SAMPLES   8096

Functions

 AST_MODULE_INFO (ASTERISK_GPL_KEY, AST_MODFLAG_DEFAULT,"mu-Law Coder/Decoder",.load=load_module,.unload=unload_module,.reload=reload,)
static int lintoulaw_framein (struct ast_trans_pvt *pvt, struct ast_frame *f)
 convert and store samples in outbuf
static struct ast_framelintoulaw_sample (void)
 LinToulaw_Sample.
static int load_module (void)
static void parse_config (void)
static int reload (void)
static int ulawtolin_framein (struct ast_trans_pvt *pvt, struct ast_frame *f)
 convert and store samples in outbuf
static struct ast_frameulawtolin_sample (void)
 ulawToLin_Sample
static int unload_module (void)

Variables

static struct ast_translator lintoulaw
 The complete translator for LinToulaw.
static struct ast_translator ulawtolin
 The complete translator for ulawToLin.


Detailed Description

codec_ulaw.c - translate between signed linear and ulaw

Definition in file codec_ulaw.c.


Define Documentation

#define BUFFER_SAMPLES   8096

Definition at line 54 of file codec_ulaw.c.


Function Documentation

AST_MODULE_INFO ( ASTERISK_GPL_KEY  ,
AST_MODFLAG_DEFAULT  ,
"mu-Law Coder/Decoder"  ,
load = load_module,
unload = unload_module,
reload = reload 
)

static int lintoulaw_framein ( struct ast_trans_pvt pvt,
struct ast_frame f 
) [static]

convert and store samples in outbuf

Definition at line 79 of file codec_ulaw.c.

References ast_trans_pvt::datalen, f, ast_trans_pvt::outbuf, and ast_trans_pvt::samples.

00080 {
00081    int i = f->samples;
00082    char *dst = pvt->outbuf + pvt->samples;
00083    int16_t *src = f->data;
00084 
00085    pvt->samples += i;
00086    pvt->datalen += i;   /* 1 byte/sample */
00087 
00088    while (i--)
00089       *dst++ = linear_to_ulaw(*src++);
00090 
00091    return 0;
00092 }

static struct ast_frame* lintoulaw_sample ( void   )  [static]

LinToulaw_Sample.

Definition at line 113 of file codec_ulaw.c.

References AST_FORMAT_SLINEAR, AST_FRAME_VOICE, f, and slin_ulaw_ex.

00114 {
00115    static struct ast_frame f;
00116    f.frametype = AST_FRAME_VOICE;
00117    f.subclass = AST_FORMAT_SLINEAR;
00118    f.datalen = sizeof(slin_ulaw_ex);
00119    /* Assume 8000 Hz */
00120    f.samples = sizeof(slin_ulaw_ex) / 2;
00121    f.mallocd = 0;
00122    f.offset = 0;
00123    f.src = __PRETTY_FUNCTION__;
00124    f.data = slin_ulaw_ex;
00125    return &f;
00126 }

static int load_module ( void   )  [static]

Definition at line 190 of file codec_ulaw.c.

References ast_register_translator, ast_unregister_translator(), lintoulaw, parse_config(), and ulawtolin.

00191 {
00192    int res;
00193 
00194    parse_config();
00195    res = ast_register_translator(&ulawtolin);
00196    if (!res)
00197       res = ast_register_translator(&lintoulaw);
00198    else
00199       ast_unregister_translator(&ulawtolin);
00200 
00201    return res;
00202 }

static void parse_config ( void   )  [static]

Definition at line 157 of file codec_ulaw.c.

References ast_config_load(), ast_true(), ast_variable_browse(), ast_verbose(), option_verbose, ulawtolin, ast_translator::useplc, var, and VERBOSE_PREFIX_3.

00158 {
00159    struct ast_variable *var;
00160    struct ast_config *cfg = ast_config_load("codecs.conf");
00161    if (!cfg)
00162       return;
00163    for (var = ast_variable_browse(cfg, "plc"); var; var = var->next) {
00164       if (!strcasecmp(var->name, "genericplc")) {
00165          ulawtolin.useplc = ast_true(var->value) ? 1 : 0;
00166          if (option_verbose > 2)
00167             ast_verbose(VERBOSE_PREFIX_3 "codec_ulaw: %susing generic PLC\n", ulawtolin.useplc ? "" : "not ");
00168       }
00169    }
00170    ast_config_destroy(cfg);
00171 }

static int reload ( void   )  [static]

Definition at line 173 of file codec_ulaw.c.

References parse_config().

00174 {
00175    parse_config();
00176 
00177    return 0;
00178 }

static int ulawtolin_framein ( struct ast_trans_pvt pvt,
struct ast_frame f 
) [static]

convert and store samples in outbuf

Definition at line 62 of file codec_ulaw.c.

References ast_trans_pvt::datalen, f, ast_trans_pvt::outbuf, and ast_trans_pvt::samples.

00063 {
00064    int i = f->samples;
00065    unsigned char *src = f->data;
00066    int16_t *dst = (int16_t *)pvt->outbuf + pvt->samples;
00067 
00068    pvt->samples += i;
00069    pvt->datalen += i * 2;  /* 2 bytes/sample */
00070 
00071    /* convert and copy in outbuf */
00072    while (i--)
00073       *dst++ = ulaw_to_linear(*src++);
00074 
00075    return 0;
00076 }

static struct ast_frame* ulawtolin_sample ( void   )  [static]

ulawToLin_Sample

*

Definition at line 95 of file codec_ulaw.c.

References AST_FORMAT_ULAW, AST_FRAME_VOICE, f, and ulaw_slin_ex.

00096 {
00097    static struct ast_frame f;
00098    f.frametype = AST_FRAME_VOICE;
00099    f.subclass = AST_FORMAT_ULAW;
00100    f.datalen = sizeof(ulaw_slin_ex);
00101    f.samples = sizeof(ulaw_slin_ex);
00102    f.mallocd = 0;
00103    f.offset = 0;
00104    f.src = __PRETTY_FUNCTION__;
00105    f.data = ulaw_slin_ex;
00106    return &f;
00107 }

static int unload_module ( void   )  [static]

Definition at line 180 of file codec_ulaw.c.

References ast_unregister_translator(), lintoulaw, and ulawtolin.

00181 {
00182    int res;
00183 
00184    res = ast_unregister_translator(&lintoulaw);
00185    res |= ast_unregister_translator(&ulawtolin);
00186 
00187    return res;
00188 }


Variable Documentation

struct ast_translator lintoulaw [static]

The complete translator for LinToulaw.

Definition at line 147 of file codec_ulaw.c.

Referenced by load_module(), and unload_module().

struct ast_translator ulawtolin [static]

The complete translator for ulawToLin.

Definition at line 132 of file codec_ulaw.c.

Referenced by load_module(), parse_config(), and unload_module().


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