Tue Nov 4 13:20:36 2008

Asterisk developer's documentation


codec_alaw.c File Reference

codec_alaw.c - translate between signed linear and alaw More...

#include "asterisk.h"
#include <fcntl.h>
#include <netinet/in.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.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/alaw.h"
#include "asterisk/utils.h"
#include "slin_ulaw_ex.h"
#include "ulaw_slin_ex.h"

Go to the source code of this file.

Defines

#define BUFFER_SAMPLES   8096

Functions

static int alawtolin_framein (struct ast_trans_pvt *pvt, struct ast_frame *f)
 decode frame into lin and fill output buffer.
static struct ast_framealawtolin_sample (void)
 alawToLin_Sample
 AST_MODULE_INFO (ASTERISK_GPL_KEY, AST_MODFLAG_DEFAULT,"A-law Coder/Decoder",.load=load_module,.unload=unload_module,.reload=reload,)
static int lintoalaw_framein (struct ast_trans_pvt *pvt, struct ast_frame *f)
 convert and store input samples in output buffer
static struct ast_framelintoalaw_sample (void)
 LinToalaw_Sample.
static int load_module (void)
static void parse_config (void)
static int reload (void)
 standard module stuff
static int unload_module (void)

Variables

static struct ast_translator alawtolin
static struct ast_translator lintoalaw


Detailed Description

codec_alaw.c - translate between signed linear and alaw

Definition in file codec_alaw.c.


Define Documentation

#define BUFFER_SAMPLES   8096

Definition at line 47 of file codec_alaw.c.


Function Documentation

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

decode frame into lin and fill output buffer.

Definition at line 55 of file codec_alaw.c.

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

00056 {
00057    int i = f->samples;
00058    unsigned char *src = f->data;
00059    int16_t *dst = (int16_t *)pvt->outbuf + pvt->samples;
00060 
00061    pvt->samples += i;
00062    pvt->datalen += i * 2;  /* 2 bytes/sample */
00063    
00064    while (i--)
00065       *dst++ = AST_ALAW(*src++);
00066 
00067    return 0;
00068 }

static struct ast_frame* alawtolin_sample ( void   )  [static]

alawToLin_Sample

Definition at line 87 of file codec_alaw.c.

References AST_FORMAT_ALAW, AST_FRAME_VOICE, f, and ulaw_slin_ex.

00088 {
00089    static struct ast_frame f;
00090    f.frametype = AST_FRAME_VOICE;
00091    f.subclass = AST_FORMAT_ALAW;
00092    f.datalen = sizeof(ulaw_slin_ex);
00093    f.samples = sizeof(ulaw_slin_ex);
00094    f.mallocd = 0;
00095    f.offset = 0;
00096    f.src = __PRETTY_FUNCTION__;
00097    f.data = ulaw_slin_ex;
00098    return &f;
00099 }

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

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

convert and store input samples in output buffer

Definition at line 71 of file codec_alaw.c.

References AST_LIN2A, ast_trans_pvt::datalen, f, ast_trans_pvt::outbuf, and ast_trans_pvt::samples.

00072 {
00073    int i = f->samples;
00074    char *dst = pvt->outbuf + pvt->samples;
00075    int16_t *src = f->data;
00076 
00077    pvt->samples += i;
00078    pvt->datalen += i;   /* 1 byte/sample */
00079 
00080    while (i--) 
00081       *dst++ = AST_LIN2A(*src++);
00082 
00083    return 0;
00084 }

static struct ast_frame* lintoalaw_sample ( void   )  [static]

LinToalaw_Sample.

Definition at line 102 of file codec_alaw.c.

References AST_FORMAT_SLINEAR, AST_FRAME_VOICE, f, and slin_ulaw_ex.

00103 {
00104    static struct ast_frame f;
00105    f.frametype = AST_FRAME_VOICE;
00106    f.subclass = AST_FORMAT_SLINEAR;
00107    f.datalen = sizeof(slin_ulaw_ex);
00108    f.samples = sizeof(slin_ulaw_ex) / 2;
00109    f.mallocd = 0;
00110    f.offset = 0;
00111    f.src = __PRETTY_FUNCTION__;
00112    f.data = slin_ulaw_ex;
00113    return &f;
00114 }

static int load_module ( void   )  [static]

Definition at line 171 of file codec_alaw.c.

References alawtolin, ast_register_translator, ast_unregister_translator(), lintoalaw, and parse_config().

00172 {
00173    int res;
00174 
00175    parse_config();
00176    res = ast_register_translator(&alawtolin);
00177    if (!res)
00178       res = ast_register_translator(&lintoalaw);
00179    else
00180       ast_unregister_translator(&alawtolin);
00181 
00182    return res;
00183 }

static void parse_config ( void   )  [static]

Definition at line 137 of file codec_alaw.c.

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

00138 {
00139    struct ast_variable *var;
00140    struct ast_config *cfg = ast_config_load("codecs.conf");
00141    if (!cfg)
00142       return;
00143    for (var = ast_variable_browse(cfg, "plc"); var; var = var->next) {
00144       if (!strcasecmp(var->name, "genericplc")) {
00145          alawtolin.useplc = ast_true(var->value) ? 1 : 0;
00146          if (option_verbose > 2)
00147             ast_verbose(VERBOSE_PREFIX_3 "codec_alaw: %susing generic PLC\n", alawtolin.useplc ? "" : "not ");
00148       }
00149    }
00150    ast_config_destroy(cfg);
00151 }

static int reload ( void   )  [static]

standard module stuff

Definition at line 155 of file codec_alaw.c.

References parse_config().

00156 {
00157    parse_config();
00158    return 0;
00159 }

static int unload_module ( void   )  [static]

Definition at line 161 of file codec_alaw.c.

References alawtolin, ast_unregister_translator(), and lintoalaw.

00162 {
00163    int res;
00164 
00165    res = ast_unregister_translator(&lintoalaw);
00166    res |= ast_unregister_translator(&alawtolin);
00167 
00168    return res;
00169 }


Variable Documentation

struct ast_translator alawtolin [static]

Definition at line 116 of file codec_alaw.c.

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

struct ast_translator lintoalaw [static]

Definition at line 127 of file codec_alaw.c.

Referenced by load_module(), and unload_module().


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