codec_zap.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Zaptel native transcoding support
 *
 * Copyright (C) 1999 - 2006, Digium, Inc.
 *
 * Mark Spencer <markster@digium.com>
 * Kevin P. Fleming <kpfleming@digium.com>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*! \file
 *
 * \brief Translate between various formats natively through Zaptel transcoding
 *
 * \ingroup codecs
 */

#include "asterisk.h"

ASTERISK_FILE_VERSION(__FILE__, "$Revision: 62173 $")

#include <fcntl.h>
#include <stdlib.h>
#include <unistd.h>
#include <netinet/in.h>
#include <string.h>
#include <stdio.h>
#include <sys/ioctl.h>
#include <errno.h>
#include <sys/mman.h>
#include <linux/zaptel.h>

#include "asterisk/lock.h"
#include "asterisk/translate.h"
#include "asterisk/config.h"
#include "asterisk/options.h"
#include "asterisk/module.h"
#include "asterisk/cli.h"
#include "asterisk/logger.h"
#include "asterisk/channel.h"
#include "asterisk/utils.h"
#include "asterisk/linkedlists.h"

#define BUFFER_SAMPLES  8000

static unsigned int global_useplc = 0;

static int totalchannels = 0;
static int complexinuse = 0;
static int simpleinuse = 0;
static int localusecnt = 0;
AST_MUTEX_DEFINE_STATIC(channelcount);

static char *tdesc = "Generic Zaptel Transcoder Codec Translator";

static char show_transcoder_usage[] =
"Usage: show transcoder\n"
"       Displays transcoder utilization.\n";

static int show_transcoder(int fd, int argc, char **argv);

static struct ast_cli_entry transcoder_cli[] = {
   { { "show", "transcoder", NULL},
   show_transcoder, "Displays transcoder utilization.",
   show_transcoder_usage}
};

struct format_map {
   unsigned int map[32][32];
};

static struct format_map global_format_map = { { { 0 } } };

struct translator {
   struct ast_translator t;
   AST_LIST_ENTRY(translator) entry;
};

static AST_LIST_HEAD_STATIC(zap_translators, translator);

struct ast_translator_pvt {
   int fd;
   int fake;
   int inuse;
   int samples;
   int dstfmt;
   int srcfmt;
#ifdef DEBUG_TRANSCODE
   int totalms;
   int lasttotalms;
#endif
   struct zt_transcode_header *hdr;
   struct ast_frame f;
};


static int show_transcoder(int fd, int argc, char **argv)
{
   ast_mutex_lock(&channelcount);

   if (!totalchannels) { 
      ast_cli(fd, "No transcoder card registered\n");
      ast_mutex_unlock(&channelcount);
      return RESULT_SUCCESS;
   }

   ast_cli(fd, "%d/%d encoders/decoders of %d channels are in use.\n", complexinuse, simpleinuse, totalchannels);

   ast_mutex_unlock(&channelcount);
   return RESULT_SUCCESS;
}

static int zap_framein(struct ast_translator_pvt *ztp, struct ast_frame *f)
{
   struct zt_transcode_header *hdr = ztp->hdr;
   if (!f->subclass) {
      /* Fake a return frame for calculation purposes */
      ztp->fake = 2;
      ztp->samples = f->samples;
      return 0;
   }
   if(!ztp->inuse) {
      ast_mutex_lock(&channelcount);
      localusecnt++;
      if(ztp->dstfmt == 8 || ztp->dstfmt == 0 ) 
         complexinuse++;
      else 
         simpleinuse++;
      ast_mutex_unlock(&channelcount);
      ztp->inuse = 1;
   }
   if (!hdr->srclen)
      /* Copy at front of buffer */
      hdr->srcoffset = 0;

   if (hdr->srclen + f->datalen > sizeof(hdr->srcdata)) {
      ast_log(LOG_WARNING, "Out of space for codec translation!\n");
      return -1;
   }

   if (hdr->srclen + f->datalen + hdr->srcoffset > sizeof(hdr->srcdata)) {
      /* Very unlikely */
      memmove(hdr->srcdata, hdr->srcdata + hdr->srcoffset, hdr->srclen);
      hdr->srcoffset = 0;
   }

   memcpy(hdr->srcdata + hdr->srcoffset + hdr->srclen, f->data, f->datalen);
   hdr->srclen += f->datalen;
   ztp->samples += f->samples;

   return -1;
}

static struct ast_frame *zap_frameout(struct ast_translator_pvt *ztp)
{
   struct zt_transcode_header *hdr = ztp->hdr;
   unsigned int x;

   if (ztp->fake == 2) {
      ztp->fake = 1;
      ztp->f.frametype = AST_FRAME_VOICE;
      ztp->f.subclass = 0;
      ztp->f.samples = 240;
      ztp->f.data = NULL;
      ztp->f.offset = 0;
      ztp->f.datalen = 0;
      ztp->f.mallocd = 0;
      ztp->samples = 0;
   } else if (ztp->fake == 1) {
      return NULL;
   } else {
      if (hdr->dstlen) {
#ifdef DEBUG_TRANSCODE
         ztp->totalms += hdr->dstsamples;
         if ((ztp->totalms - ztp->lasttotalms) > 8000) {
            ast_verbose("Whee %p, %d (%d to %d)\n", ztp, hdr->dstlen, ztp->lasttotalms, ztp->totalms);
            ztp->lasttotalms = ztp->totalms;
         }
#endif
         ztp->f.frametype = AST_FRAME_VOICE;
         ztp->f.subclass = hdr->dstfmt;
         ztp->f.samples = hdr->dstsamples;
         ztp->f.data = hdr->dstdata + hdr->dstoffset;
         ztp->f.offset = hdr->dstoffset;
         ztp->f.datalen = hdr->dstlen;
         ztp->f.mallocd = 0;
         ztp->samples -= ztp->f.samples;
         hdr->dstlen = 0;
         
      } else {
         if (hdr->srclen) {
            hdr->dstoffset = AST_FRIENDLY_OFFSET;
            x = ZT_TCOP_TRANSCODE;
            if (ioctl(ztp->fd, ZT_TRANSCODE_OP, &x))
               ast_log(LOG_WARNING, "Failed to transcode: %s\n", strerror(errno));
         }
         return NULL;
      }
   }

   return &ztp->f;
}

static void zap_destroy(struct ast_translator_pvt *ztp)
{
   unsigned int x;

   x = ZT_TCOP_RELEASE;
   if (ioctl(ztp->fd, ZT_TRANSCODE_OP, &x))
      ast_log(LOG_WARNING, "Failed to release transcoder channel: %s\n", strerror(errno));
            
   munmap(ztp->hdr, sizeof(*ztp->hdr));
   if(ztp->inuse) {
      ast_mutex_lock(&channelcount);
      localusecnt--;
      if(ztp->dstfmt == 8 || ztp->dstfmt == 0)
         complexinuse--;
      else
         simpleinuse--;
      ast_mutex_unlock(&channelcount);
   }
   close(ztp->fd);
}

static struct ast_translator_pvt *zap_new_alawtog723(void)
{
   /* Request translation through zap if possible */
   int fd;
   unsigned int x = ZT_TCOP_ALLOCATE;
   struct ast_translator_pvt *ztp;
   struct zt_transcode_header *hdr;
   int flags;
   
   ztp = calloc(1,sizeof(struct ast_translator_pvt));
   if(!ztp) {
      ast_log(LOG_ERROR, "Could not allocate ztp structure.\n");
      return NULL;
   }
   ztp->dstfmt = 0;
   ztp->srcfmt = 3;

   if ((fd = open("/dev/zap/transcode", O_RDWR)) < 0)
      return NULL;
   flags = fcntl(fd, F_GETFL);
   if (flags > - 1) {
      if (fcntl(fd, F_SETFL, flags | O_NONBLOCK))
         ast_log(LOG_WARNING, "Could not set non-block mode!\n");
   }
   

   if ((hdr = mmap(NULL, sizeof(*hdr), PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0)) == MAP_FAILED) {
      ast_log(LOG_ERROR, "Memory Map failed for transcoding (%s)\n", strerror(errno));
      close(fd);

      return NULL;
   }

   if (hdr->magic != ZT_TRANSCODE_MAGIC) {
      ast_log(LOG_ERROR, "Transcoder header (%08x) wasn't magic.  Abandoning\n", hdr->magic);
      munmap(hdr, sizeof(*hdr));
      close(fd);

      return NULL;
   }
   
   hdr->srcfmt = (1 << ztp->srcfmt);
   hdr->dstfmt = (1 << ztp->dstfmt);
   if (ioctl(fd, ZT_TRANSCODE_OP, &x)) {
      ast_log(LOG_ERROR, "Unable to attach transcoder: %s\n", strerror(errno));
      munmap(hdr, sizeof(*hdr));
      close(fd);

      return NULL;
   }

   ztp->fd = fd;
   ztp->hdr = hdr;

   return (struct ast_translator_pvt *) ztp;
}

static struct ast_translator_pvt *zap_new_ulawtog723(void)
{
   /* Request translation through zap if possible */
   int fd;
   unsigned int x = ZT_TCOP_ALLOCATE;
   struct ast_translator_pvt *ztp;
   struct zt_transcode_header *hdr;
   int flags;
   
   ztp = calloc(1,sizeof(struct ast_translator_pvt));
   if(!ztp) {
      ast_log(LOG_ERROR, "Could not allocate ztp structure.\n");
      return NULL;
   }
   ztp->dstfmt = 0;
   ztp->srcfmt = 2;

   if ((fd = open("/dev/zap/transcode", O_RDWR)) < 0)
      return NULL;
   flags = fcntl(fd, F_GETFL);
   if (flags > - 1) {
      if (fcntl(fd, F_SETFL, flags | O_NONBLOCK))
         ast_log(LOG_WARNING, "Could not set non-block mode!\n");
   }
   

   if ((hdr = mmap(NULL, sizeof(*hdr), PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0)) == MAP_FAILED) {
      ast_log(LOG_ERROR, "Memory Map failed for transcoding (%s)\n", strerror(errno));
      close(fd);

      return NULL;
   }

   if (hdr->magic != ZT_TRANSCODE_MAGIC) {
      ast_log(LOG_ERROR, "Transcoder header (%08x) wasn't magic.  Abandoning\n", hdr->magic);
      munmap(hdr, sizeof(*hdr));
      close(fd);

      return NULL;
   }
   
   hdr->srcfmt = (1 << ztp->srcfmt);
   hdr->dstfmt = (1 << ztp->dstfmt);
   if (ioctl(fd, ZT_TRANSCODE_OP, &x)) {
      ast_log(LOG_ERROR, "Unable to attach transcoder: %s\n", strerror(errno));
      munmap(hdr, sizeof(*hdr));
      close(fd);

      return NULL;
   }

   ztp->fd = fd;
   ztp->hdr = hdr;

   return (struct ast_translator_pvt *) ztp;
}

static struct ast_translator_pvt *zap_new_g723toalaw(void)
{
   /* Request translation through zap if possible */
   int fd;
   unsigned int x = ZT_TCOP_ALLOCATE;
   struct ast_translator_pvt *ztp;
   struct zt_transcode_header *hdr;
   int flags;
   
   ztp = calloc(1,sizeof(struct ast_translator_pvt));
   if(!ztp) {
      ast_log(LOG_ERROR, "Could not allocate ztp structure.\n");
      return NULL;
   }
   ztp->dstfmt = 3;
   ztp->srcfmt = 0;

   if ((fd = open("/dev/zap/transcode", O_RDWR)) < 0)
      return NULL;
   flags = fcntl(fd, F_GETFL);
   if (flags > - 1) {
      if (fcntl(fd, F_SETFL, flags | O_NONBLOCK))
         ast_log(LOG_WARNING, "Could not set non-block mode!\n");
   }
   

   if ((hdr = mmap(NULL, sizeof(*hdr), PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0)) == MAP_FAILED) {
      ast_log(LOG_ERROR, "Memory Map failed for transcoding (%s)\n", strerror(errno));
      close(fd);

      return NULL;
   }

   if (hdr->magic != ZT_TRANSCODE_MAGIC) {
      ast_log(LOG_ERROR, "Transcoder header (%08x) wasn't magic.  Abandoning\n", hdr->magic);
      munmap(hdr, sizeof(*hdr));
      close(fd);

      return NULL;
   }
   
   hdr->srcfmt = (1 << ztp->srcfmt);
   hdr->dstfmt = (1 << ztp->dstfmt);
   if (ioctl(fd, ZT_TRANSCODE_OP, &x)) {
      ast_log(LOG_ERROR, "Unable to attach transcoder: %s\n", strerror(errno));
      munmap(hdr, sizeof(*hdr));
      close(fd);

      return NULL;
   }

   ztp->fd = fd;
   ztp->hdr = hdr;

   return (struct ast_translator_pvt *) ztp;
}

static struct ast_translator_pvt *zap_new_g723toulaw(void)
{
   /* Request translation through zap if possible */
   int fd;
   unsigned int x = ZT_TCOP_ALLOCATE;
   struct ast_translator_pvt *ztp;
   struct zt_transcode_header *hdr;
   int flags;
   
   ztp = calloc(1,sizeof(struct ast_translator_pvt));
   if(!ztp) {
      ast_log(LOG_ERROR, "Could not allocate ztp structure.\n");
      return NULL;
   }
   ztp->dstfmt = 2;
   ztp->srcfmt = 0;

   if ((fd = open("/dev/zap/transcode", O_RDWR)) < 0)
      return NULL;
   flags = fcntl(fd, F_GETFL);
   if (flags > - 1) {
      if (fcntl(fd, F_SETFL, flags | O_NONBLOCK))
         ast_log(LOG_WARNING, "Could not set non-block mode!\n");
   }
   

   if ((hdr = mmap(NULL, sizeof(*hdr), PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0)) == MAP_FAILED) {
      ast_log(LOG_ERROR, "Memory Map failed for transcoding (%s)\n", strerror(errno));
      close(fd);

      return NULL;
   }

   if (hdr->magic != ZT_TRANSCODE_MAGIC) {
      ast_log(LOG_ERROR, "Transcoder header (%08x) wasn't magic.  Abandoning\n", hdr->magic);
      munmap(hdr, sizeof(*hdr));
      close(fd);

      return NULL;
   }
   
   hdr->srcfmt = (1 << ztp->srcfmt);
   hdr->dstfmt = (1 << ztp->dstfmt);
   if (ioctl(fd, ZT_TRANSCODE_OP, &x)) {
      ast_log(LOG_ERROR, "Unable to attach transcoder: %s\n", strerror(errno));
      munmap(hdr, sizeof(*hdr));
      close(fd);

      return NULL;
   }

   ztp->fd = fd;
   ztp->hdr = hdr;

   return (struct ast_translator_pvt *) ztp;
}

static struct ast_translator_pvt *zap_new_alawtog729(void)
{
   /* Request translation through zap if possible */
   int fd;
   unsigned int x = ZT_TCOP_ALLOCATE;
   struct ast_translator_pvt *ztp;
   struct zt_transcode_header *hdr;
   int flags;
   
   ztp = calloc(1,sizeof(struct ast_translator_pvt));
   if(!ztp) {
      ast_log(LOG_ERROR, "Could not allocate ztp structure.\n");
      return NULL;
   }
   ztp->dstfmt = 8;
   ztp->srcfmt = 3;

   if ((fd = open("/dev/zap/transcode", O_RDWR)) < 0)
      return NULL;
   flags = fcntl(fd, F_GETFL);
   if (flags > - 1) {
      if (fcntl(fd, F_SETFL, flags | O_NONBLOCK))
         ast_log(LOG_WARNING, "Could not set non-block mode!\n");
   }
   

   if ((hdr = mmap(NULL, sizeof(*hdr), PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0)) == MAP_FAILED) {
      ast_log(LOG_ERROR, "Memory Map failed for transcoding (%s)\n", strerror(errno));
      close(fd);

      return NULL;
   }

   if (hdr->magic != ZT_TRANSCODE_MAGIC) {
      ast_log(LOG_ERROR, "Transcoder header (%08x) wasn't magic.  Abandoning\n", hdr->magic);
      munmap(hdr, sizeof(*hdr));
      close(fd);

      return NULL;
   }
   
   hdr->srcfmt = (1 << ztp->srcfmt);
   hdr->dstfmt = (1 << ztp->dstfmt);
   if (ioctl(fd, ZT_TRANSCODE_OP, &x)) {
      ast_log(LOG_ERROR, "Unable to attach transcoder: %s\n", strerror(errno));
      munmap(hdr, sizeof(*hdr));
      close(fd);

      return NULL;
   }

   ztp->fd = fd;
   ztp->hdr = hdr;

   return (struct ast_translator_pvt *) ztp;
}

static struct ast_translator_pvt *zap_new_ulawtog729(void)
{
   /* Request translation through zap if possible */
   int fd;
   unsigned int x = ZT_TCOP_ALLOCATE;
   struct ast_translator_pvt *ztp;
   struct zt_transcode_header *hdr;
   int flags;
   
   ztp = calloc(1,sizeof(struct ast_translator_pvt));
   if(!ztp) {
      ast_log(LOG_ERROR, "Could not allocate ztp structure.\n");
      return NULL;
   }
   ztp->dstfmt = 8;
   ztp->srcfmt = 2;

   if ((fd = open("/dev/zap/transcode", O_RDWR)) < 0)
      return NULL;
   flags = fcntl(fd, F_GETFL);
   if (flags > - 1) {
      if (fcntl(fd, F_SETFL, flags | O_NONBLOCK))
         ast_log(LOG_WARNING, "Could not set non-block mode!\n");
   }
   

   if ((hdr = mmap(NULL, sizeof(*hdr), PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0)) == MAP_FAILED) {
      ast_log(LOG_ERROR, "Memory Map failed for transcoding (%s)\n", strerror(errno));
      close(fd);

      return NULL;
   }

   if (hdr->magic != ZT_TRANSCODE_MAGIC) {
      ast_log(LOG_ERROR, "Transcoder header (%08x) wasn't magic.  Abandoning\n", hdr->magic);
      munmap(hdr, sizeof(*hdr));
      close(fd);

      return NULL;
   }
   
   hdr->srcfmt = (1 << ztp->srcfmt);
   hdr->dstfmt = (1 << ztp->dstfmt);
   if (ioctl(fd, ZT_TRANSCODE_OP, &x)) {
      ast_log(LOG_ERROR, "Unable to attach transcoder: %s\n", strerror(errno));
      munmap(hdr, sizeof(*hdr));
      close(fd);

      return NULL;
   }

   ztp->fd = fd;
   ztp->hdr = hdr;

   return (struct ast_translator_pvt *) ztp;
}

static struct ast_translator_pvt *zap_new_g729toalaw(void)
{
   /* Request translation through zap if possible */
   int fd;
   unsigned int x = ZT_TCOP_ALLOCATE;
   struct ast_translator_pvt *ztp;
   struct zt_transcode_header *hdr;
   int flags;
   
   ztp = calloc(1,sizeof(struct ast_translator_pvt));
   if(!ztp) {
      ast_log(LOG_ERROR, "Could not allocate ztp structure.\n");
      return NULL;
   }
   ztp->dstfmt = 3;
   ztp->srcfmt = 8;

   if ((fd = open("/dev/zap/transcode", O_RDWR)) < 0)
      return NULL;
   flags = fcntl(fd, F_GETFL);
   if (flags > - 1) {
      if (fcntl(fd, F_SETFL, flags | O_NONBLOCK))
         ast_log(LOG_WARNING, "Could not set non-block mode!\n");
   }
   

   if ((hdr = mmap(NULL, sizeof(*hdr), PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0)) == MAP_FAILED) {
      ast_log(LOG_ERROR, "Memory Map failed for transcoding (%s)\n", strerror(errno));
      close(fd);

      return NULL;
   }

   if (hdr->magic != ZT_TRANSCODE_MAGIC) {
      ast_log(LOG_ERROR, "Transcoder header (%08x) wasn't magic.  Abandoning\n", hdr->magic);
      munmap(hdr, sizeof(*hdr));
      close(fd);

      return NULL;
   }
   
   hdr->srcfmt = (1 << ztp->srcfmt);
   hdr->dstfmt = (1 << ztp->dstfmt);
   if (ioctl(fd, ZT_TRANSCODE_OP, &x)) {
      ast_log(LOG_ERROR, "Unable to attach transcoder: %s\n", strerror(errno));
      munmap(hdr, sizeof(*hdr));
      close(fd);

      return NULL;
   }

   ztp->fd = fd;
   ztp->hdr = hdr;

   return (struct ast_translator_pvt *) ztp;
}

static struct ast_translator_pvt *zap_new_g729toulaw(void)
{
   /* Request translation through zap if possible */
   int fd;
   unsigned int x = ZT_TCOP_ALLOCATE;
   struct ast_translator_pvt *ztp;
   struct zt_transcode_header *hdr;
   int flags;
   
   ztp = calloc(1,sizeof(struct ast_translator_pvt));
   if(!ztp) {
      ast_log(LOG_ERROR, "Could not allocate ztp structure.\n");
      return NULL;
   }
   ztp->dstfmt = 2;
   ztp->srcfmt = 8;

   if ((fd = open("/dev/zap/transcode", O_RDWR)) < 0)
      return NULL;
   flags = fcntl(fd, F_GETFL);
   if (flags > - 1) {
      if (fcntl(fd, F_SETFL, flags | O_NONBLOCK))
         ast_log(LOG_WARNING, "Could not set non-block mode!\n");
   }
   

   if ((hdr = mmap(NULL, sizeof(*hdr), PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0)) == MAP_FAILED) {
      ast_log(LOG_ERROR, "Memory Map failed for transcoding (%s)\n", strerror(errno));
      close(fd);

      return NULL;
   }

   if (hdr->magic != ZT_TRANSCODE_MAGIC) {
      ast_log(LOG_ERROR, "Transcoder header (%08x) wasn't magic.  Abandoning\n", hdr->magic);
      munmap(hdr, sizeof(*hdr));
      close(fd);

      return NULL;
   }
   
   hdr->srcfmt = (1 << ztp->srcfmt);
   hdr->dstfmt = (1 << ztp->dstfmt);
   if (ioctl(fd, ZT_TRANSCODE_OP, &x)) {
      ast_log(LOG_ERROR, "Unable to attach transcoder: %s\n", strerror(errno));
      munmap(hdr, sizeof(*hdr));
      close(fd);

      return NULL;
   }

   ztp->fd = fd;
   ztp->hdr = hdr;

   return (struct ast_translator_pvt *) ztp;
}

static struct ast_frame *fakesrc_sample(void)
{
   /* Don't bother really trying to test hardware ones. */
   static struct ast_frame f = {
      .frametype = AST_FRAME_VOICE,
      .samples = 240,
      .src = __PRETTY_FUNCTION__
   };

   return &f;
}

static int register_translator(int dst, int src)
{
   struct translator *zt;
   int res;

   if (!(zt = calloc(1, sizeof(*zt)))) {
      ast_log(LOG_ERROR, "Could not allocate translator\n");
      return -1;
   }

   snprintf((char *) (zt->t.name), sizeof(zt->t.name), "zap%sto%s", 
       ast_getformatname((1 << src)), ast_getformatname((1 << dst)));

   if(src == 8 && dst == 2) /* G.729 to Ulaw */
      zt->t.newpvt = zap_new_g729toulaw;
   else if(src == 8 && dst == 3) /* G.729 to Alaw */
      zt->t.newpvt = zap_new_g729toalaw;
   else if(src == 2 && dst == 8) /* Ulaw to G.729 */
      zt->t.newpvt = zap_new_ulawtog729;
   else if(src == 3 && dst == 8) /* Alaw to G.729 */
      zt->t.newpvt = zap_new_alawtog729;
   else if(src == 0 && dst == 2) /* G.723 to Ulaw */
      zt->t.newpvt = zap_new_g723toulaw;
   else if(src == 0 && dst == 3) /* G.723 to Alaw */
      zt->t.newpvt = zap_new_g723toalaw;
   else if(src == 2 && dst == 0) /* Ulaw to G.723 */
      zt->t.newpvt = zap_new_ulawtog723;
   else if(src == 3 && dst == 0) /* Alaw to G.723 */
      zt->t.newpvt = zap_new_alawtog723;

   zt->t.frameout = zap_frameout;
   zt->t.destroy = zap_destroy;
   zt->t.sample = fakesrc_sample;
   zt->t.framein = zap_framein;
   zt->t.srcfmt = (1 << src);
   zt->t.dstfmt = (1 << dst);
   if ((res = ast_register_translator(&zt->t))) {
      free(zt);
      return -1;
   }

   AST_LIST_LOCK(&zap_translators);
   AST_LIST_INSERT_HEAD(&zap_translators, zt, entry);
   AST_LIST_UNLOCK(&zap_translators);

   global_format_map.map[dst][src] = 1;

   return res;
}

static void drop_translator(int dst, int src)
{
   struct translator *cur;

   AST_LIST_LOCK(&zap_translators);
   AST_LIST_TRAVERSE_SAFE_BEGIN(&zap_translators, cur, entry) {
      if (cur->t.srcfmt != src)
         continue;

      if (cur->t.dstfmt != dst)
         continue;

      AST_LIST_REMOVE_CURRENT(&zap_translators, entry);
      ast_unregister_translator(&cur->t);
      free(cur);
      global_format_map.map[dst][src] = 0;
      break;
   }
   AST_LIST_TRAVERSE_SAFE_END;
   AST_LIST_UNLOCK(&zap_translators);
}

static void unregister_translators(void)
{
   struct translator *cur;

   AST_LIST_LOCK(&zap_translators);
   while ((cur = AST_LIST_REMOVE_HEAD(&zap_translators, entry))) {
      ast_unregister_translator(&cur->t);
      free(cur);
   }
   AST_LIST_UNLOCK(&zap_translators);
}

static void parse_config(void)
{
   struct ast_variable *var;
   struct ast_config *cfg = ast_config_load("codecs.conf");

   if (!cfg)
      return;

   for (var = ast_variable_browse(cfg, "plc"); var; var = var->next) {
      if (!strcasecmp(var->name, "genericplc")) {
         global_useplc = ast_true(var->value);
         if (option_verbose > 2)
            ast_verbose(VERBOSE_PREFIX_3 "codec_zap: %susing generic PLC\n", global_useplc ? "" : "not ");
      }
   }

   ast_config_destroy(cfg);
}

static int build_translators(struct format_map *map, unsigned int dstfmts, unsigned int srcfmts)
{
   unsigned int src, dst;

   for (src = 0; src < 32; src++) {
      for (dst = 0; dst < 32; dst++) {
         if (!(srcfmts & (1<< src)))
            continue;

         if (!(dstfmts & (1 << dst)))
            continue;

         if (global_format_map.map[dst][src])
            continue;

         if (!register_translator(dst, src))
            map->map[dst][src] = 1;
         else
            return 0;
      }
   }
   return 1;
}

static int find_transcoders(void)
{
   struct zt_transcode_info info = { 0, };
   struct format_map map = { { { 0 } } };
   int fd, res;
   unsigned int x, y;

   info.op = ZT_TCOP_GETINFO;
   if ((fd = open("/dev/zap/transcode", O_RDWR)) < 0) {
      ast_log(LOG_DEBUG, "No Zaptel transcoder support!\n");
      return 0;
   }

   ast_mutex_lock(&channelcount);
   totalchannels = 0;
   ast_mutex_unlock(&channelcount);

   for (info.tcnum = 0; !(res = ioctl(fd, ZT_TRANSCODE_OP, &info)); info.tcnum++) {
      if (option_verbose > 1)
         ast_verbose(VERBOSE_PREFIX_2 "Found transcoder '%s'.\n", info.name);

      if(build_translators(&map, info.dstfmts, info.srcfmts)) {
         ast_mutex_lock(&channelcount);
         totalchannels += info.numchannels;
         ast_mutex_unlock(&channelcount);
      }
   }
   close(fd);

   if (!info.tcnum && (option_verbose > 1))
      ast_verbose(VERBOSE_PREFIX_2 "No hardware transcoders found.\n");

   for (x = 0; x < 32; x++) {
      for (y = 0; y < 32; y++) {
         if (!map.map[x][y] && global_format_map.map[x][y])
            drop_translator(x, y);
      }
   }
   ast_mutex_lock(&channelcount);
   totalchannels = totalchannels/2;
   ast_mutex_unlock(&channelcount);
   return 0;
}

int reload(void)
{
   parse_config();

   return 0;
}

int unload_module(void)
{
   if(!localusecnt)
      return -1;
   unregister_translators();
   ast_cli_unregister_multiple(transcoder_cli, sizeof(transcoder_cli) / sizeof(struct ast_cli_entry));
   return 0;
}

int load_module(void)
{
   ast_mutex_init(&channelcount);
   parse_config();

   find_transcoders();
   ast_cli_register_multiple(transcoder_cli, sizeof(transcoder_cli) / sizeof(struct ast_cli_entry));
   return 0;
}

char *description(void)
{
   return tdesc;
}

int usecount(void)
{
   int res;
   STANDARD_USECOUNT(res);
   return res;
}

char *key()
{
   return ASTERISK_GPL_KEY;
}