codecs/codec_ulaw.c

   1 /*
   2  * Asterisk -- An open source telephony toolkit.
   3  *
   4  * Copyright (C) 1999 - 2005, Digium, Inc.
   5  *
   6  * Mark Spencer <markster@digium.com>
   7  *
   8  * See http://www.asterisk.org for more information about
   9  * the Asterisk project. Please do not directly contact
  10  * any of the maintainers of this project for assistance;
  11  * the project provides a web site, mailing lists and IRC
  12  * channels for your use.
  13  *
  14  * This program is free software, distributed under the terms of
  15  * the GNU General Public License Version 2. See the LICENSE file
  16  * at the top of the source tree.
  17  */
  18
  19 /*! \file
  20  *
  21  * \brief codec_ulaw.c - translate between signed linear and ulaw
  22  *
  23  * \ingroup codecs
  24  */
  25
  26 #include "asterisk.h"
  27
  28 ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
  29
  30 #include <fcntl.h>
  31 #include <netinet/in.h>
  32 #include <stdio.h>
  33 #include <stdlib.h>
  34 #include <string.h>
  35 #include <unistd.h>
  36
  37 #include "asterisk/lock.h"
  38 #include "asterisk/logger.h"
  39 #include "asterisk/module.h"
  40 #include "asterisk/config.h"
  41 #include "asterisk/options.h"
  42 #include "asterisk/translate.h"
  43 #include "asterisk/channel.h"
  44 #include "asterisk/ulaw.h"
  45 #include "asterisk/utils.h"
  46
  47 #define BUFFER_SAMPLES   8096   /* size for the translation buffers */
  48
  49 /* Sample frame data */
  50
  51 #include "slin_ulaw_ex.h"
  52 #include "ulaw_slin_ex.h"
  53
  54 /*! \brief convert and store samples in outbuf */
  55 static int ulawtolin_framein(struct ast_trans_pvt *pvt, struct ast_frame *f)
  56 {
  57         int i = f->samples;
  58         unsigned char *src = f->data;
  59         int16_t *dst = (int16_t *)pvt->outbuf + pvt->samples;
  60
  61         pvt->samples += i;
  62         pvt->datalen += i * 2;  /* 2 bytes/sample */
  63
  64         /* convert and copy in outbuf */
  65         while (i--)
  66                 *dst++ = AST_MULAW(*src++);
  67
  68         return 0;
  69 }
  70
  71 /*! \brief convert and store samples in outbuf */
  72 static int lintoulaw_framein(struct ast_trans_pvt *pvt, struct ast_frame *f)
  73 {
  74         int i = f->samples;
  75         char *dst = pvt->outbuf + pvt->samples;
  76         int16_t *src = f->data;
  77
  78         pvt->samples += i;
  79         pvt->datalen += i;      /* 1 byte/sample */
  80
  81         while (i--)
  82                 *dst++ = AST_LIN2MU(*src++);
  83
  84         return 0;
  85 }
  86
  87 /*!  * \brief ulawToLin_Sample */
  88 static struct ast_frame *ulawtolin_sample(void)
  89 {
  90         static struct ast_frame f;
  91         f.frametype = AST_FRAME_VOICE;
  92         f.subclass = AST_FORMAT_ULAW;
  93         f.datalen = sizeof(ulaw_slin_ex);
  94         f.samples = sizeof(ulaw_slin_ex);
  95         f.mallocd = 0;
  96         f.offset = 0;
  97         f.src = __PRETTY_FUNCTION__;
  98         f.data = ulaw_slin_ex;
  99         return &f;
 100 }
 101
 102 /*!
 103  * \brief LinToulaw_Sample
 104  */
 105
 106 static struct ast_frame *lintoulaw_sample(void)
 107 {
 108         static struct ast_frame f;
 109         f.frametype = AST_FRAME_VOICE;
 110         f.subclass = AST_FORMAT_SLINEAR;
 111         f.datalen = sizeof(slin_ulaw_ex);
 112         /* Assume 8000 Hz */
 113         f.samples = sizeof(slin_ulaw_ex) / 2;
 114         f.mallocd = 0;
 115         f.offset = 0;
 116         f.src = __PRETTY_FUNCTION__;
 117         f.data = slin_ulaw_ex;
 118         return &f;
 119 }
 120
 121 /*!
 122  * \brief The complete translator for ulawToLin.
 123  */
 124
 125 static struct ast_translator ulawtolin = {
 126         .name = "ulawtolin",
 127         .srcfmt = AST_FORMAT_ULAW,
 128         .dstfmt = AST_FORMAT_SLINEAR,
 129         .framein = ulawtolin_framein,
 130         .sample = ulawtolin_sample,
 131         .buffer_samples = BUFFER_SAMPLES,
 132         .buf_size = BUFFER_SAMPLES * 2,
 133         .plc_samples = 160,
 134 };
 135
 136 /*!
 137  * \brief The complete translator for LinToulaw.
 138  */
 139
 140 static struct ast_translator lintoulaw = {
 141         .name = "lintoulaw",
 142         .srcfmt = AST_FORMAT_SLINEAR,
 143         .dstfmt = AST_FORMAT_ULAW,
 144         .framein = lintoulaw_framein,
 145         .sample = lintoulaw_sample,
 146         .buf_size = BUFFER_SAMPLES,
 147         .buffer_samples = BUFFER_SAMPLES,
 148 };
 149
 150 static void parse_config(void)
 151 {
 152         struct ast_variable *var;
 153         struct ast_config *cfg = ast_config_load("codecs.conf");
 154         if (!cfg)
 155                 return;
 156         for (var = ast_variable_browse(cfg, "plc"); var; var = var->next) {
 157                 if (!strcasecmp(var->name, "genericplc")) {
 158                         ulawtolin.useplc = ast_true(var->value) ? 1 : 0;
 159                         if (option_verbose > 2)
 160                                 ast_verbose(VERBOSE_PREFIX_3 "codec_ulaw: %susing generic PLC\n", ulawtolin.useplc ? "" : "not ");
 161                 }
 162         }
 163         ast_config_destroy(cfg);
 164 }
 165
 166 static int reload(void)
 167 {
 168         parse_config();
 169
 170         return 0;
 171 }
 172
 173 static int unload_module(void)
 174 {
 175         int res;
 176
 177         res = ast_unregister_translator(&lintoulaw);
 178         res |= ast_unregister_translator(&ulawtolin);
 179
 180         return res;
 181 }
 182
 183 static int load_module(void)
 184 {
 185         int res;
 186
 187         parse_config();
 188         res = ast_register_translator(&ulawtolin);
 189         if (!res)
 190                 res = ast_register_translator(&lintoulaw);
 191         else
 192                 ast_unregister_translator(&ulawtolin);
 193
 194         return res;
 195 }
 196
 197 AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_DEFAULT, "mu-Law Coder/Decoder",
 198                 .load = load_module,
 199                 .unload = unload_module,
 200                 .reload = reload,
 201                );