codecs/codec_alaw.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_alaw.c - translate between signed linear and alaw
  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/alaw.h"
  45 #include "asterisk/utils.h"
  46
  47 #define BUFFER_SAMPLES   8096   /* size for the translation buffers */
  48
  49 /* Sample frame data (Mu data is okay) */
  50
  51 #include "slin_ulaw_ex.h"
  52 #include "ulaw_slin_ex.h"
  53
  54 /*! \brief decode frame into lin and fill output buffer. */
  55 static int alawtolin_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         while (i--)
  65                 *dst++ = AST_ALAW(*src++);
  66
  67         return 0;
  68 }
  69
  70 /*! \brief convert and store input samples in output buffer */
  71 static int lintoalaw_framein(struct ast_trans_pvt *pvt, struct ast_frame *f)
  72 {
  73         int i = f->samples;
  74         char *dst = pvt->outbuf + pvt->samples;
  75         int16_t *src = f->data;
  76
  77         pvt->samples += i;
  78         pvt->datalen += i;      /* 1 byte/sample */
  79
  80         while (i--)
  81                 *dst++ = AST_LIN2A(*src++);
  82
  83         return 0;
  84 }
  85
  86 /*! \brief alawToLin_Sample */
  87 static struct ast_frame *alawtolin_sample(void)
  88 {
  89         static struct ast_frame f;
  90         f.frametype = AST_FRAME_VOICE;
  91         f.subclass = AST_FORMAT_ALAW;
  92         f.datalen = sizeof(ulaw_slin_ex);
  93         f.samples = sizeof(ulaw_slin_ex);
  94         f.mallocd = 0;
  95         f.offset = 0;
  96         f.src = __PRETTY_FUNCTION__;
  97         f.data = ulaw_slin_ex;
  98         return &f;
  99 }
 100
 101 /*! \brief LinToalaw_Sample */
 102 static struct ast_frame *lintoalaw_sample(void)
 103 {
 104         static struct ast_frame f;
 105         f.frametype = AST_FRAME_VOICE;
 106         f.subclass = AST_FORMAT_SLINEAR;
 107         f.datalen = sizeof(slin_ulaw_ex);
 108         f.samples = sizeof(slin_ulaw_ex) / 2;
 109         f.mallocd = 0;
 110         f.offset = 0;
 111         f.src = __PRETTY_FUNCTION__;
 112         f.data = slin_ulaw_ex;
 113         return &f;
 114 }
 115
 116 static struct ast_translator alawtolin = {
 117         .name = "alawtolin",
 118         .srcfmt = AST_FORMAT_ALAW,
 119         .dstfmt = AST_FORMAT_SLINEAR,
 120         .framein = alawtolin_framein,
 121         .sample = alawtolin_sample,
 122         .buffer_samples = BUFFER_SAMPLES,
 123         .buf_size = BUFFER_SAMPLES * 2,
 124         .plc_samples = 160,
 125 };
 126
 127 static struct ast_translator lintoalaw = {
 128         "lintoalaw",
 129         .srcfmt = AST_FORMAT_SLINEAR,
 130         .dstfmt = AST_FORMAT_ALAW,
 131         .framein = lintoalaw_framein,
 132         .sample = lintoalaw_sample,
 133         .buffer_samples = BUFFER_SAMPLES,
 134         .buf_size = BUFFER_SAMPLES,
 135 };
 136
 137 static void parse_config(void)
 138 {
 139         struct ast_variable *var;
 140         struct ast_config *cfg = ast_config_load("codecs.conf");
 141         if (!cfg)
 142                 return;
 143         for (var = ast_variable_browse(cfg, "plc"); var; var = var->next) {
 144                 if (!strcasecmp(var->name, "genericplc")) {
 145                         alawtolin.useplc = ast_true(var->value) ? 1 : 0;
 146                         if (option_verbose > 2)
 147                                 ast_verbose(VERBOSE_PREFIX_3 "codec_alaw: %susing generic PLC\n", alawtolin.useplc ? "" : "not ");
 148                 }
 149         }
 150         ast_config_destroy(cfg);
 151 }
 152
 153 /*! \brief standard module stuff */
 154
 155 static int reload(void)
 156 {
 157         parse_config();
 158         return 0;
 159 }
 160
 161 static int unload_module(void)
 162 {
 163         int res;
 164
 165         res = ast_unregister_translator(&lintoalaw);
 166         res |= ast_unregister_translator(&alawtolin);
 167
 168         return res;
 169 }
 170
 171 static int load_module(void)
 172 {
 173         int res;
 174
 175         parse_config();
 176         res = ast_register_translator(&alawtolin);
 177         if (!res)
 178                 res = ast_register_translator(&lintoalaw);
 179         else
 180                 ast_unregister_translator(&alawtolin);
 181
 182         return res;
 183 }
 184
 185 AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_DEFAULT, "A-law Coder/Decoder",
 186                 .load = load_module,
 187                 .unload = unload_module,
 188                 .reload = reload,
 189                );