152 lines
3.6 KiB
C
152 lines
3.6 KiB
C
/*
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* Asterisk -- An open source telephony toolkit.
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*
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* Copyright (C) 1999 - 2005, Digium, Inc.
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*
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* Mark Spencer <markster@digium.com>
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*
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* See http://www.asterisk.org for more information about
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* the Asterisk project. Please do not directly contact
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* any of the maintainers of this project for assistance;
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* the project provides a web site, mailing lists and IRC
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* channels for your use.
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*
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* This program is free software, distributed under the terms of
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* the GNU General Public License Version 2. See the LICENSE file
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* at the top of the source tree.
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*/
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/*! \file
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*
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* \brief codec_alaw.c - translate between signed linear and alaw
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*
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* \ingroup codecs
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*/
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#include "asterisk.h"
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ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
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#include "asterisk/module.h"
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#include "asterisk/config.h"
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#include "asterisk/translate.h"
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#include "asterisk/alaw.h"
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#include "asterisk/utils.h"
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#define BUFFER_SAMPLES 8096 /* size for the translation buffers */
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/* Sample frame data */
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#include "asterisk/slin.h"
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#include "ex_alaw.h"
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/*! \brief decode frame into lin and fill output buffer. */
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static int alawtolin_framein(struct ast_trans_pvt *pvt, struct ast_frame *f)
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{
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int i = f->samples;
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unsigned char *src = f->data.ptr;
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int16_t *dst = pvt->outbuf.i16 + pvt->samples;
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pvt->samples += i;
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pvt->datalen += i * 2; /* 2 bytes/sample */
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while (i--)
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*dst++ = AST_ALAW(*src++);
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return 0;
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}
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/*! \brief convert and store input samples in output buffer */
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static int lintoalaw_framein(struct ast_trans_pvt *pvt, struct ast_frame *f)
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{
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int i = f->samples;
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char *dst = pvt->outbuf.c + pvt->samples;
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int16_t *src = f->data.ptr;
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pvt->samples += i;
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pvt->datalen += i; /* 1 byte/sample */
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while (i--)
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*dst++ = AST_LIN2A(*src++);
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return 0;
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}
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static struct ast_translator alawtolin = {
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.name = "alawtolin",
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.srcfmt = AST_FORMAT_ALAW,
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.dstfmt = AST_FORMAT_SLINEAR,
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.framein = alawtolin_framein,
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.sample = alaw_sample,
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.buffer_samples = BUFFER_SAMPLES,
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.buf_size = BUFFER_SAMPLES * 2,
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.plc_samples = 160,
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};
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static struct ast_translator lintoalaw = {
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"lintoalaw",
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.srcfmt = AST_FORMAT_SLINEAR,
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.dstfmt = AST_FORMAT_ALAW,
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.framein = lintoalaw_framein,
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.sample = slin8_sample,
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.buffer_samples = BUFFER_SAMPLES,
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.buf_size = BUFFER_SAMPLES,
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};
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static int parse_config(int reload)
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{
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struct ast_variable *var;
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struct ast_flags config_flags = { reload ? CONFIG_FLAG_FILEUNCHANGED : 0 };
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struct ast_config *cfg = ast_config_load("codecs.conf", config_flags);
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if (cfg == CONFIG_STATUS_FILEMISSING || cfg == CONFIG_STATUS_FILEUNCHANGED || cfg == CONFIG_STATUS_FILEINVALID)
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return 0;
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for (var = ast_variable_browse(cfg, "plc"); var; var = var->next) {
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if (!strcasecmp(var->name, "genericplc")) {
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alawtolin.useplc = ast_true(var->value) ? 1 : 0;
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ast_verb(3, "codec_alaw: %susing generic PLC\n", alawtolin.useplc ? "" : "not ");
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}
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}
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ast_config_destroy(cfg);
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return 0;
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}
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/*! \brief standard module stuff */
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static int reload(void)
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{
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if (parse_config(1))
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return AST_MODULE_LOAD_DECLINE;
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return AST_MODULE_LOAD_SUCCESS;
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}
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static int unload_module(void)
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{
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int res;
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res = ast_unregister_translator(&lintoalaw);
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res |= ast_unregister_translator(&alawtolin);
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return res;
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}
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static int load_module(void)
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{
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int res;
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if (parse_config(0))
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return AST_MODULE_LOAD_DECLINE;
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res = ast_register_translator(&alawtolin);
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if (!res)
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res = ast_register_translator(&lintoalaw);
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else
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ast_unregister_translator(&alawtolin);
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if (res)
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return AST_MODULE_LOAD_FAILURE;
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return AST_MODULE_LOAD_SUCCESS;
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}
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AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_DEFAULT, "A-law Coder/Decoder",
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.load = load_module,
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.unload = unload_module,
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.reload = reload,
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);
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