Wed Oct 28 11:46:06 2009

Asterisk developer's documentation


codec_a_mu.c File Reference

codec_a_mu.c - translate between alaw and ulaw directly More...

#include "asterisk.h"
#include "asterisk/module.h"
#include "asterisk/translate.h"
#include "asterisk/alaw.h"
#include "asterisk/ulaw.h"
#include "asterisk/utils.h"
#include "ulaw_slin_ex.h"

Include dependency graph for codec_a_mu.c:

Go to the source code of this file.

Defines

#define BUFFER_SAMPLES   8000

Functions

static void __reg_module (void)
static void __unreg_module (void)
static int alawtoulaw_framein (struct ast_trans_pvt *pvt, struct ast_frame *f)
 convert frame data and store into the buffer
static struct ast_framealawtoulaw_sample (void)
static int load_module (void)
static int ulawtoalaw_framein (struct ast_trans_pvt *pvt, struct ast_frame *f)
 convert frame data and store into the buffer
static struct ast_frameulawtoalaw_sample (void)
static int unload_module (void)
 standard module glue

Variables

static struct ast_module_info __mod_info = { .name = AST_MODULE, .flags = AST_MODFLAG_DEFAULT , .description = "A-law and Mulaw direct Coder/Decoder" , .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 = AST_BUILDOPT_SUM, .load = load_module, .unload = unload_module, }
static unsigned char a2mu [256]
static struct ast_translator alawtoulaw
static const struct
ast_module_info
ast_module_info = &__mod_info
static unsigned char mu2a [256]
static struct ast_translator ulawtoalaw


Detailed Description

codec_a_mu.c - translate between alaw and ulaw directly

Definition in file codec_a_mu.c.


Define Documentation

#define BUFFER_SAMPLES   8000


Function Documentation

static void __reg_module ( void   )  [static]

Definition at line 159 of file codec_a_mu.c.

static void __unreg_module ( void   )  [static]

Definition at line 159 of file codec_a_mu.c.

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

convert frame data and store into the buffer

Definition at line 46 of file codec_a_mu.c.

References ast_frame::data, ast_trans_pvt::datalen, ast_trans_pvt::outbuf, ast_trans_pvt::samples, and ast_frame::samples.

00047 {
00048    int x = f->samples;
00049    unsigned char *src = f->data;
00050    unsigned char *dst = (unsigned char *)pvt->outbuf + pvt->samples;
00051 
00052    pvt->samples += x;
00053    pvt->datalen += x;
00054 
00055    while (x--)
00056       *dst++ = a2mu[*src++];
00057 
00058    return 0;
00059 }

static struct ast_frame* alawtoulaw_sample ( void   )  [static, read]

Definition at line 80 of file codec_a_mu.c.

References AST_FORMAT_ALAW, AST_FRAME_VOICE, ast_frame::data, ast_frame::datalen, ast_frame::frametype, ast_frame::mallocd, ast_frame::offset, ast_frame::samples, ast_frame::src, ast_frame::subclass, and ulaw_slin_ex.

00081 {
00082    static struct ast_frame f;
00083    f.frametype = AST_FRAME_VOICE;
00084    f.subclass = AST_FORMAT_ALAW;
00085    f.datalen = sizeof(ulaw_slin_ex);
00086    f.samples = sizeof(ulaw_slin_ex);
00087    f.mallocd = 0;
00088    f.offset = 0;
00089    f.src = __PRETTY_FUNCTION__;
00090    f.data = ulaw_slin_ex; /* XXX what ? */
00091    return &f;
00092 }

static int load_module ( void   )  [static]

Definition at line 140 of file codec_a_mu.c.

References AST_ALAW, AST_LIN2A, AST_LIN2MU, AST_MODULE_LOAD_FAILURE, AST_MODULE_LOAD_SUCCESS, AST_MULAW, ast_register_translator, and ast_unregister_translator().

00141 {
00142    int res;
00143    int x;
00144 
00145    for (x=0;x<256;x++) {
00146       mu2a[x] = AST_LIN2A(AST_MULAW(x));
00147       a2mu[x] = AST_LIN2MU(AST_ALAW(x));
00148    }
00149    res = ast_register_translator(&alawtoulaw);
00150    if (!res)
00151       res = ast_register_translator(&ulawtoalaw);
00152    else
00153       ast_unregister_translator(&alawtoulaw);
00154    if (res)
00155       return AST_MODULE_LOAD_FAILURE;
00156    return AST_MODULE_LOAD_SUCCESS;
00157 }

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

convert frame data and store into the buffer

Definition at line 62 of file codec_a_mu.c.

References ast_frame::data, ast_trans_pvt::datalen, ast_trans_pvt::outbuf, ast_trans_pvt::samples, and ast_frame::samples.

00063 {
00064    int x = f->samples;
00065    unsigned char *src = f->data;
00066    unsigned char *dst = (unsigned char *)pvt->outbuf + pvt->samples;
00067 
00068    pvt->samples += x;
00069    pvt->datalen += x;
00070 
00071    while (x--)
00072       *dst++ = mu2a[*src++];
00073 
00074    return 0;
00075 }

static struct ast_frame* ulawtoalaw_sample ( void   )  [static, read]

Definition at line 94 of file codec_a_mu.c.

References AST_FORMAT_ULAW, AST_FRAME_VOICE, ast_frame::data, ast_frame::datalen, ast_frame::frametype, ast_frame::mallocd, ast_frame::offset, ast_frame::samples, ast_frame::src, ast_frame::subclass, and ulaw_slin_ex.

00095 {
00096    static struct ast_frame f;
00097    f.frametype = AST_FRAME_VOICE;
00098    f.subclass = AST_FORMAT_ULAW;
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 }

static int unload_module ( void   )  [static]

standard module glue

Definition at line 130 of file codec_a_mu.c.

References ast_unregister_translator().

00131 {
00132    int res;
00133 
00134    res = ast_unregister_translator(&ulawtoalaw);
00135    res |= ast_unregister_translator(&alawtoulaw);
00136 
00137    return res;
00138 }


Variable Documentation

struct ast_module_info __mod_info = { .name = AST_MODULE, .flags = AST_MODFLAG_DEFAULT , .description = "A-law and Mulaw direct Coder/Decoder" , .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 = AST_BUILDOPT_SUM, .load = load_module, .unload = unload_module, } [static]

Definition at line 159 of file codec_a_mu.c.

unsigned char a2mu[256] [static]

Definition at line 39 of file codec_a_mu.c.

struct ast_translator alawtoulaw [static]

Definition at line 108 of file codec_a_mu.c.

const struct ast_module_info* ast_module_info = &__mod_info [static]

Definition at line 159 of file codec_a_mu.c.

unsigned char mu2a[256] [static]

Definition at line 38 of file codec_a_mu.c.

struct ast_translator ulawtoalaw [static]

Definition at line 118 of file codec_a_mu.c.


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