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: 201096 $")

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

/*!
 * \brief Initialize an slinfactory
 *
 * \arg sf The slinfactory to initialize
 *
 * \return Nothing
 */
void ast_slinfactory_init(struct ast_slinfactory *sf) 
{
   memset(sf, 0, sizeof(*sf));
   sf->offset = sf->hold;
}

/*!
 * \brief Destroy the contents of a slinfactory
 *
 * \arg sf The slinfactory that is no longer needed
 *
 * This function will free any memory allocated for the contents of the
 * slinfactory.  It does not free the slinfactory itself.  If the sf is
 * malloc'd, then it must be explicitly free'd after calling this function.
 *
 * \return Nothing
 */
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);
}

/*!
 * \brief Feed audio into an slinfactory
 *
 * \arg sf The slinfactory to feed into
 * \arg f Frame containing audio to feed in
 *
 * \return Number of frames currently in factory
 */
int ast_slinfactory_feed(struct ast_slinfactory *sf, struct ast_frame *f)
{
   struct ast_frame *begin_frame = f, *duped_frame = NULL, *frame_ptr;
   unsigned int x = 0;

   /* In some cases, we can be passed a frame which has no data in it, but
    * which has a positive number of samples defined. Once such situation is
    * when a jitter buffer is in use and the jitter buffer interpolates a frame.
    * The frame it produces has data set to NULL, datalen set to 0, and samples
    * set to either 160 or 240.
    */
   if (!f->data.ptr) {
      return 0;
   }

   if (f->subclass != AST_FORMAT_SLINEAR && f->subclass != AST_FORMAT_SLINEAR16) {
      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((f->subclass == AST_FORMAT_G722 ? AST_FORMAT_SLINEAR16 : AST_FORMAT_SLINEAR), f->subclass))) {
            ast_log(LOG_WARNING, "Cannot build a path from %s to slin\n", ast_getformatname(f->subclass));
            return 0;
         }
         sf->format = f->subclass;
      }

      if (!(begin_frame = ast_translate(sf->trans, f, 0))) {
         return 0;
      }
      
      if (!(duped_frame = ast_frisolate(begin_frame))) {
         return 0;
      }

      if (duped_frame != begin_frame) {
         ast_frfree(begin_frame);
      }
   } else {
      if (sf->trans) {
         ast_translator_free_path(sf->trans);
         sf->trans = NULL;
      }
      if (!(duped_frame = ast_frdup(f)))
         return 0;
   }

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

   /* if the frame was translated, the translator may have returned multiple
      frames, so process each of them
   */
   for (begin_frame = duped_frame; begin_frame; begin_frame = AST_LIST_NEXT(begin_frame, frame_list)) {
      AST_LIST_INSERT_TAIL(&sf->queue, begin_frame, frame_list);
      sf->size += begin_frame->samples;
   }

   return x;
}

/*!
 * \brief Read samples from an slinfactory
 *
 * \arg sf The slinfactory to read from
 * \arg buf Buffer to put samples into
 * \arg samples Number of samples wanted
 *
 * \return Number of samples read
 */
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 (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.ptr;
         
         if (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;
            if (remain > (AST_SLINFACTORY_MAX_HOLD - sf->holdlen)) {
               remain = AST_SLINFACTORY_MAX_HOLD - sf->holdlen;
            }
            memcpy(sf->hold, frame_data, remain * sizeof(*offset));
            sf->holdlen = remain;
         }
         ast_frfree(frame_ptr);
      } else {
         break;
      }
   }

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

/*!
 * \brief Retrieve number of samples currently in an slinfactory
 *
 * \arg sf The slinfactory to peek into
 *
 * \return Number of samples in slinfactory
 */
unsigned int ast_slinfactory_available(const struct ast_slinfactory *sf)
{
   return sf->size;
}

/*!
 * \brief Flush the contents of an slinfactory
 *
 * \arg sf The slinfactory to flush
 *
 * \return Nothing
 */
void ast_slinfactory_flush(struct ast_slinfactory *sf)
{
   struct ast_frame *fr = NULL;

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

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

   sf->size = sf->holdlen = 0;
   sf->offset = sf->hold;

   return;
}