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>
 */
 
/*** MODULEINFO
    <support_level>core</support_level>
 ***/
 
#include "asterisk.h"
 
#include "asterisk/frame.h"
#include "asterisk/format_cache.h"
#include "asterisk/slinfactory.h"
#include "asterisk/translate.h"
#include "asterisk/astobj2.h"
 
void ast_slinfactory_init(struct ast_slinfactory *sf)
{
    memset(sf, 0, sizeof(*sf));
    sf->offset = sf->hold;
    sf->output_format = ao2_bump(ast_format_slin);
}
 
int ast_slinfactory_init_with_format(struct ast_slinfactory *sf, struct ast_format *slin_out)
{
    memset(sf, 0, sizeof(*sf));
    sf->offset = sf->hold;
    if (!ast_format_cache_is_slinear(slin_out)) {
        return -1;
    }
    sf->output_format = ao2_bump(slin_out);
 
    return 0;
}
 
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);
    }
 
    ao2_cleanup(sf->output_format);
    sf->output_format = NULL;
    ao2_cleanup(sf->format);
    sf->format = NULL;
}
 
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 (ast_format_cmp(f->subclass.format, sf->output_format) == AST_FORMAT_CMP_NOT_EQUAL) {
        if (sf->trans && (ast_format_cmp(f->subclass.format, sf->format) == AST_FORMAT_CMP_NOT_EQUAL)) {
            ast_translator_free_path(sf->trans);
            sf->trans = NULL;
        }
 
        if (!sf->trans) {
            if (!(sf->trans = ast_translator_build_path(sf->output_format, f->subclass.format))) {
                ast_log(LOG_WARNING, "Cannot build a path from %s (%u)to %s (%u)\n",
                    ast_format_get_name(f->subclass.format),
                    ast_format_get_codec_id(f->subclass.format),
                    ast_format_get_name(sf->output_format),
                    ast_format_get_codec_id(sf->output_format));
                return 0;
            }
            ao2_replace(sf->format, f->subclass.format);
        }
 
        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;
}
 
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->offset, 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;
}
 
unsigned int ast_slinfactory_available(const struct ast_slinfactory *sf)
{
    return sf->size;
}
 
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;
}