codec_gsm.c File Reference

Translate between signed linear and Global System for Mobile Communications (GSM) More...

#include "asterisk.h"
#include "asterisk/translate.h"
#include "asterisk/config.h"
#include "asterisk/module.h"
#include "asterisk/utils.h"
#include "asterisk/linkedlists.h"
#include "gsm.h"
#include "../formats/msgsm.h"
#include "asterisk/slin.h"
#include "ex_gsm.h"

Include dependency graph for codec_gsm.c:

Go to the source code of this file.

Data Structures
struct	gsm_translator_pvt

Macros
#define	BUFFER_SAMPLES   8000
#define	GSM_FRAME_LEN   33
#define	GSM_SAMPLES   160
#define	MSGSM_FRAME_LEN   65

Functions
static void	__reg_module (void)
static void	__unreg_module (void)
struct ast_module *	AST_MODULE_SELF_SYM (void)
static void	gsm_destroy_stuff (struct ast_trans_pvt *pvt)
static int	gsm_new (struct ast_trans_pvt *pvt)
static int	gsmtolin_framein (struct ast_trans_pvt *pvt, struct ast_frame *f)
	decode and store in outbuf. More...
static int	lintogsm_framein (struct ast_trans_pvt *pvt, struct ast_frame *f)
	store samples into working buffer for later decode More...
static struct ast_frame *	lintogsm_frameout (struct ast_trans_pvt *pvt)
	encode and produce a frame More...
static int	load_module (void)
static int	unload_module (void)

Variables
static struct ast_module_info	__mod_info = { .name = AST_MODULE, .flags = AST_MODFLAG_DEFAULT , .description = "GSM 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, .support_level = AST_MODULE_SUPPORT_CORE, .load = load_module, .unload = unload_module, }
static const struct ast_module_info *	ast_module_info = &__mod_info
static struct ast_translator	gsmtolin
static struct ast_translator	lintogsm

Detailed Description

Translate between signed linear and Global System for Mobile Communications (GSM)

Definition in file codec_gsm.c.

Macro Definition Documentation

BUFFER_SAMPLES

#define BUFFER_SAMPLES   8000

Definition at line 50 of file codec_gsm.c.

GSM_FRAME_LEN

#define GSM_FRAME_LEN   33

Definition at line 52 of file codec_gsm.c.

GSM_SAMPLES

#define GSM_SAMPLES   160

Definition at line 51 of file codec_gsm.c.

MSGSM_FRAME_LEN

#define MSGSM_FRAME_LEN   65

Definition at line 53 of file codec_gsm.c.

Function Documentation

__reg_module()

static void __reg_module ( void  )

static

Definition at line 252 of file codec_gsm.c.

__unreg_module()

static void __unreg_module ( void  )

static

Definition at line 252 of file codec_gsm.c.

AST_MODULE_SELF_SYM()

struct ast_module * AST_MODULE_SELF_SYM

(

void

)

Definition at line 252 of file codec_gsm.c.

gsm_destroy_stuff()

static void gsm_destroy_stuff ( struct ast_trans_pvt *  pvt )

static

Definition at line 172 of file codec_gsm.c.

{
    struct gsm_translator_pvt *tmp = pvt->pvt;
    if (tmp->gsm)
        gsm_destroy(tmp->gsm);
}

References ast_trans_pvt::pvt, and tmp().

gsm_new()

static int gsm_new ( struct ast_trans_pvt *  pvt )

static

Definition at line 64 of file codec_gsm.c.

{
    struct gsm_translator_pvt *tmp = pvt->pvt;
 
    return (tmp->gsm = gsm_create()) ? 0 : -1;
}

References ast_trans_pvt::pvt, and tmp().

gsmtolin_framein()

static int gsmtolin_framein ( struct ast_trans_pvt *  pvt, struct ast_frame *  f  )

static

decode and store in outbuf.

Definition at line 72 of file codec_gsm.c.

{
    struct gsm_translator_pvt *tmp = pvt->pvt;
    int x;
    int16_t *dst = pvt->outbuf.i16;
    /* guess format from frame len. 65 for MSGSM, 33 for regular GSM */
    int flen = (f->datalen % MSGSM_FRAME_LEN == 0) ?
        MSGSM_FRAME_LEN : GSM_FRAME_LEN;
 
    for (x=0; x < f->datalen; x += flen) {
        unsigned char data[2 * GSM_FRAME_LEN];
        unsigned char *src;
        int len;
        if (flen == MSGSM_FRAME_LEN) {
            len = 2*GSM_SAMPLES;
            src = data;
            /* Translate MSGSM format to Real GSM format before feeding in */
            /* XXX what's the point here! we should just work
             * on the full format.
             */
            conv65(f->data.ptr + x, data);
        } else {
            len = GSM_SAMPLES;
            src = f->data.ptr + x;
        }
        /* XXX maybe we don't need to check */
        if (pvt->samples + len > BUFFER_SAMPLES) {
            ast_log(LOG_WARNING, "Out of buffer space\n");
            return -1;
        }
        if (gsm_decode(tmp->gsm, src, dst + pvt->samples)) {
            ast_log(LOG_WARNING, "Invalid GSM data (1)\n");
            return -1;
        }
        pvt->samples += GSM_SAMPLES;
        pvt->datalen += 2 * GSM_SAMPLES;
        if (flen == MSGSM_FRAME_LEN) {
            if (gsm_decode(tmp->gsm, data + GSM_FRAME_LEN, dst + pvt->samples)) {
                ast_log(LOG_WARNING, "Invalid GSM data (2)\n");
                return -1;
            }
            pvt->samples += GSM_SAMPLES;
            pvt->datalen += 2 * GSM_SAMPLES;
        }
    }
    return 0;
}

References ast_log, BUFFER_SAMPLES, conv65(), ast_frame::data, ast_frame::datalen, ast_trans_pvt::datalen, GSM_FRAME_LEN, GSM_SAMPLES, ast_trans_pvt::i16, len(), LOG_WARNING, MSGSM_FRAME_LEN, ast_trans_pvt::outbuf, ast_frame::ptr, ast_trans_pvt::pvt, ast_trans_pvt::samples, and tmp().

lintogsm_framein()

static int lintogsm_framein ( struct ast_trans_pvt *  pvt, struct ast_frame *  f  )

static

store samples into working buffer for later decode

Definition at line 121 of file codec_gsm.c.

{
    struct gsm_translator_pvt *tmp = pvt->pvt;
 
    /* XXX We should look at how old the rest of our stream is, and if it
       is too old, then we should overwrite it entirely, otherwise we can
       get artifacts of earlier talk that do not belong */
    if (pvt->samples + f->samples > BUFFER_SAMPLES) {
        ast_log(LOG_WARNING, "Out of buffer space\n");
        return -1;
    }
    memcpy(tmp->buf + pvt->samples, f->data.ptr, f->datalen);
    pvt->samples += f->samples;
    return 0;
}

References ast_log, BUFFER_SAMPLES, ast_frame::data, ast_frame::datalen, LOG_WARNING, ast_frame::ptr, ast_trans_pvt::pvt, ast_frame::samples, ast_trans_pvt::samples, and tmp().

lintogsm_frameout()

static struct ast_frame * lintogsm_frameout ( struct ast_trans_pvt *  pvt )

static

encode and produce a frame

Definition at line 138 of file codec_gsm.c.

{
    struct gsm_translator_pvt *tmp = pvt->pvt;
    struct ast_frame *result = NULL;
    struct ast_frame *last = NULL;
    int samples = 0; /* output samples */
 
    while (pvt->samples >= GSM_SAMPLES) {
        struct ast_frame *current;
 
        /* Encode a frame of data */
        gsm_encode(tmp->gsm, tmp->buf + samples, (gsm_byte *) pvt->outbuf.c);
        samples += GSM_SAMPLES;
        pvt->samples -= GSM_SAMPLES;
 
        current = ast_trans_frameout(pvt, GSM_FRAME_LEN, GSM_SAMPLES);
        if (!current) {
            continue;
        } else if (last) {
            AST_LIST_NEXT(last, frame_list) = current;
        } else {
            result = current;
        }
        last = current;
    }
 
    /* Move the data at the end of the buffer to the front */
    if (samples) {
        memmove(tmp->buf, tmp->buf + samples, pvt->samples * 2);
    }
 
    return result;
}

References AST_LIST_NEXT, ast_trans_frameout(), ast_trans_pvt::c, current, GSM_FRAME_LEN, GSM_SAMPLES, last, NULL, ast_trans_pvt::outbuf, ast_trans_pvt::pvt, result, ast_frame::samples, ast_trans_pvt::samples, and tmp().

load_module()

static int load_module ( void  )

static

Definition at line 233 of file codec_gsm.c.

{
    int res;
 
    res = ast_register_translator(&gsmtolin);
    res |= ast_register_translator(&lintogsm);
 
    if (res) {
        unload_module();
        return AST_MODULE_LOAD_DECLINE;
    }
 
    return AST_MODULE_LOAD_SUCCESS;
}

References AST_MODULE_LOAD_DECLINE, AST_MODULE_LOAD_SUCCESS, ast_register_translator, gsmtolin, lintogsm, and unload_module().

unload_module()

static int unload_module ( void  )

static

Definition at line 223 of file codec_gsm.c.

{
    int res;
 
    res = ast_unregister_translator(&lintogsm);
    res |= ast_unregister_translator(&gsmtolin);
 
    return res;
}

References ast_unregister_translator(), gsmtolin, and lintogsm.

Referenced by load_module().

Variable Documentation

__mod_info

struct ast_module_info __mod_info = { .name = AST_MODULE, .flags = AST_MODFLAG_DEFAULT , .description = "GSM 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, .support_level = AST_MODULE_SUPPORT_CORE, .load = load_module, .unload = unload_module, }

static

Definition at line 252 of file codec_gsm.c.

ast_module_info

const struct ast_module_info* ast_module_info = &__mod_info

static

Definition at line 252 of file codec_gsm.c.

gsmtolin

struct ast_translator gsmtolin

static

Definition at line 179 of file codec_gsm.c.

Referenced by load_module(), and unload_module().

lintogsm

struct ast_translator lintogsm

static

Definition at line 201 of file codec_gsm.c.

Referenced by load_module(), and unload_module().