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Last updated: Sat Feb 3 05:00:57 2007

Asterisk developer's documentation :: Codename Pineapple

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slinfactory.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2005, Anthony Minessale II.
 *
 * Anthony Minessale <anthmct@yahoo.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 A machine to gather up arbitrary frames and convert them
 * to raw slinear on demand.
 *
 * \author Anthony Minessale <anthmct@yahoo.com>
 */

#include "asterisk.h"

ASTERISK_FILE_VERSION(__FILE__, "$Revision: 43696 $")

#include <string.h>

#include "asterisk/frame.h"
#include "asterisk/slinfactory.h"
#include "asterisk/logger.h"
#include "asterisk/translate.h"

void ast_slinfactory_init(struct ast_slinfactory *sf) 
{
   memset(sf, 0, sizeof(*sf));
   sf->offset = sf->hold;
}

void ast_slinfactory_destroy(struct ast_slinfactory *sf) 
{
   struct ast_frame *f;

   if (sf->trans) {
      ast_translator_free_path(sf->trans);
      sf->trans = NULL;
   }

   while ((f = AST_LIST_REMOVE_HEAD(&sf->queue, frame_list)))
      ast_frfree(f);
}

int ast_slinfactory_feed(struct ast_slinfactory *sf, struct ast_frame *f)
{
   struct ast_frame *frame, *frame_ptr;
   unsigned int x;

   if (f->subclass != AST_FORMAT_SLINEAR) {
      if (sf->trans && f->subclass != sf->format) {
         ast_translator_free_path(sf->trans);
         sf->trans = NULL;
      }
      if (!sf->trans) {
         if ((sf->trans = ast_translator_build_path(AST_FORMAT_SLINEAR, f->subclass)) == NULL) {
            ast_log(LOG_WARNING, "Cannot build a path from %s to slin\n", ast_getformatname(f->subclass));
            return 0;
         } else {
            sf->format = f->subclass;
         }
      }
   }

   if (!(frame = ast_frdup( (sf->trans) ? ast_translate(sf->trans, f, 0) : f )))
      return 0;

   x = 0;
   AST_LIST_TRAVERSE(&sf->queue, frame_ptr, frame_list)
      x++;

   AST_LIST_INSERT_TAIL(&sf->queue, frame, frame_list);

   sf->size += frame->samples;

   return x;
}

int ast_slinfactory_read(struct ast_slinfactory *sf, short *buf, size_t samples) 
{
   struct ast_frame *frame_ptr;
   unsigned int sofar = 0, ineed, remain;
   short *frame_data, *offset = buf;

   while (sofar < samples) {
      ineed = samples - sofar;

      if (sf->holdlen) {
         if ((sofar + sf->holdlen) <= ineed) {
            memcpy(offset, sf->hold, sf->holdlen * sizeof(*offset));
            sofar += sf->holdlen;
            offset += sf->holdlen;
            sf->holdlen = 0;
            sf->offset = sf->hold;
         } else {
            remain = sf->holdlen - ineed;
            memcpy(offset, sf->offset, ineed * sizeof(*offset));
            sofar += ineed;
            sf->offset += ineed;
            sf->holdlen = remain;
         }
         continue;
      }
      
      if ((frame_ptr = AST_LIST_REMOVE_HEAD(&sf->queue, frame_list))) {
         frame_data = frame_ptr->data;
         
         if ((sofar + frame_ptr->samples) <= ineed) {
            memcpy(offset, frame_data, frame_ptr->samples * sizeof(*offset));
            sofar += frame_ptr->samples;
            offset += frame_ptr->samples;
         } else {
            remain = frame_ptr->samples - ineed;
            memcpy(offset, frame_data, ineed * sizeof(*offset));
            sofar += ineed;
            frame_data += ineed;
            memcpy(sf->hold, frame_data, remain * sizeof(*offset));
            sf->holdlen = remain;
         }
         ast_frfree(frame_ptr);
      } else {
         break;
      }
   }

   sf->size -= sofar;
   return sofar;
}

unsigned int ast_slinfactory_available(const struct ast_slinfactory *sf)
{
   return sf->size;
}

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