Mon Mar 31 07:40:04 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 <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/alaw.h"
#include "asterisk/utils.h"
#include "slin_ulaw_ex.h"
#include "ulaw_slin_ex.h"

Include dependency graph for codec_alaw.c:

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 54 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 62 of file codec_alaw.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    while (i--)
00072       *dst++ = alaw_to_linear(*src++);
00073 
00074    return 0;
00075 }

static struct ast_frame* alawtolin_sample ( void   )  [static]

alawToLin_Sample

Definition at line 94 of file codec_alaw.c.

References AST_FORMAT_ALAW, AST_FRAME_VOICE, f, and ulaw_slin_ex.

00095 {
00096    static struct ast_frame f;
00097    f.frametype = AST_FRAME_VOICE;
00098    f.subclass = AST_FORMAT_ALAW;
00099    f.datalen = sizeof(ulaw_slin_ex);
00100    f.samples = sizeof(ulaw_slin_ex);
00101    f.mallocd = 0;
00102    f.offset = 0;
00103    f.src = __PRETTY_FUNCTION__;
00104    f.data = ulaw_slin_ex;
00105    return &f;
00106 }

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 78 of file codec_alaw.c.

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

00079 {
00080    int i = f->samples;
00081    char *dst = pvt->outbuf + pvt->samples;
00082    int16_t *src = f->data;
00083 
00084    pvt->samples += i;
00085    pvt->datalen += i;   /* 1 byte/sample */
00086 
00087    while (i--) 
00088       *dst++ = linear_to_alaw(*src++);
00089 
00090    return 0;
00091 }

static struct ast_frame* lintoalaw_sample ( void   )  [static]

LinToalaw_Sample.

Definition at line 109 of file codec_alaw.c.

References AST_FORMAT_SLINEAR, AST_FRAME_VOICE, f, and slin_ulaw_ex.

00110 {
00111    static struct ast_frame f;
00112    f.frametype = AST_FRAME_VOICE;
00113    f.subclass = AST_FORMAT_SLINEAR;
00114    f.datalen = sizeof(slin_ulaw_ex);
00115    f.samples = sizeof(slin_ulaw_ex) / 2;
00116    f.mallocd = 0;
00117    f.offset = 0;
00118    f.src = __PRETTY_FUNCTION__;
00119    f.data = slin_ulaw_ex;
00120    return &f;
00121 }

static int load_module ( void   )  [static]

Definition at line 178 of file codec_alaw.c.

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

00179 {
00180    int res;
00181 
00182    parse_config();
00183    res = ast_register_translator(&alawtolin);
00184    if (!res)
00185       res = ast_register_translator(&lintoalaw);
00186    else
00187       ast_unregister_translator(&alawtolin);
00188 
00189    return res;
00190 }

static void parse_config ( void   )  [static]

Definition at line 144 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.

00145 {
00146    struct ast_variable *var;
00147    struct ast_config *cfg = ast_config_load("codecs.conf");
00148    if (!cfg)
00149       return;
00150    for (var = ast_variable_browse(cfg, "plc"); var; var = var->next) {
00151       if (!strcasecmp(var->name, "genericplc")) {
00152          alawtolin.useplc = ast_true(var->value) ? 1 : 0;
00153          if (option_verbose > 2)
00154             ast_verbose(VERBOSE_PREFIX_3 "codec_alaw: %susing generic PLC\n", alawtolin.useplc ? "" : "not ");
00155       }
00156    }
00157    ast_config_destroy(cfg);
00158 }

static int reload ( void   )  [static]

standard module stuff

Definition at line 162 of file codec_alaw.c.

References parse_config().

00163 {
00164    parse_config();
00165    return 0;
00166 }

static int unload_module ( void   )  [static]

Definition at line 168 of file codec_alaw.c.

References alawtolin, ast_unregister_translator(), and lintoalaw.

00169 {
00170    int res;
00171 
00172    res = ast_unregister_translator(&lintoalaw);
00173    res |= ast_unregister_translator(&alawtolin);
00174 
00175    return res;
00176 }


Variable Documentation

struct ast_translator alawtolin [static]

Definition at line 123 of file codec_alaw.c.

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

struct ast_translator lintoalaw [static]

Definition at line 134 of file codec_alaw.c.

Referenced by load_module(), and unload_module().


Generated on Mon Mar 31 07:40:04 2008 for Asterisk - the Open Source PBX by  doxygen 1.5.1