/*****************************************************************************
 * audio_output.c : audio output instance miscellaneous functions
 *****************************************************************************
 * Copyright (C) 2002 VideoLAN
 * $Id: audio_output.c,v 1.100 2002/08/30 22:22:24 massiot Exp $
 *
 * Authors: Christophe Massiot <massiot@via.ecp.fr>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
 *****************************************************************************/

/*****************************************************************************
 * Preamble
 *****************************************************************************/
#include <stdlib.h>                            /* calloc(), malloc(), free() */
#include <string.h>

#include <vlc/vlc.h>

#ifdef HAVE_ALLOCA_H
#   include <alloca.h>
#endif

#include "audio_output.h"
#include "aout_internal.h"

/*
 * Instances management (see also input.c:aout_InputNew())
 */

/*****************************************************************************
 * aout_NewInstance: initialize aout structure
 *****************************************************************************/
aout_instance_t * __aout_NewInstance( vlc_object_t * p_parent )
{
    aout_instance_t * p_aout;

    /* Allocate descriptor. */
    p_aout = vlc_object_create( p_parent, VLC_OBJECT_AOUT );
    if( p_aout == NULL )
    {
        return NULL;
    }

    /* Initialize members. */
    vlc_mutex_init( p_parent, &p_aout->input_fifos_lock );
    vlc_mutex_init( p_parent, &p_aout->mixer_lock );
    vlc_mutex_init( p_parent, &p_aout->output_fifo_lock );
    p_aout->i_nb_inputs = 0;

    vlc_object_attach( p_aout, p_parent->p_vlc );

    return p_aout;
}

/*****************************************************************************
 * aout_DeleteInstance: destroy aout structure
 *****************************************************************************/
void aout_DeleteInstance( aout_instance_t * p_aout )
{
    vlc_mutex_destroy( &p_aout->input_fifos_lock );
    vlc_mutex_destroy( &p_aout->mixer_lock );
    vlc_mutex_destroy( &p_aout->output_fifo_lock );

    /* Free structure. */
    vlc_object_destroy( p_aout );
}


/*
 * Buffer management (interface to the decoders)
 */

/*****************************************************************************
 * aout_BufferNew : ask for a new empty buffer
 *****************************************************************************/
aout_buffer_t * aout_BufferNew( aout_instance_t * p_aout,
                                aout_input_t * p_input,
                                size_t i_nb_samples )
{
    aout_buffer_t * p_buffer;
    mtime_t duration = (1000000 * (mtime_t)i_nb_samples)
                        / p_input->input.i_rate;

    /* This necessarily allocates in the heap. */
    aout_BufferAlloc( &p_input->input_alloc, duration, NULL, p_buffer );
    p_buffer->i_nb_samples = i_nb_samples;
    p_buffer->i_nb_bytes = i_nb_samples * p_input->input.i_bytes_per_frame
                              / p_input->input.i_frame_length;

    if ( p_buffer == NULL )
    {
        msg_Err( p_aout, "NULL buffer !" );
    }
    else
    {
        p_buffer->start_date = p_buffer->end_date = 0;
    }

    return p_buffer;
}

/*****************************************************************************
 * aout_BufferDelete : destroy an undecoded buffer
 *****************************************************************************/
void aout_BufferDelete( aout_instance_t * p_aout, aout_input_t * p_input,
                        aout_buffer_t * p_buffer )
{
    aout_BufferFree( p_buffer );
}

/*****************************************************************************
 * aout_BufferPlay : filter & mix the decoded buffer
 *****************************************************************************/
void aout_BufferPlay( aout_instance_t * p_aout, aout_input_t * p_input,
                      aout_buffer_t * p_buffer )
{
    if ( p_buffer->start_date == 0 )
    {
        msg_Warn( p_aout, "non-dated buffer received" );
        aout_BufferFree( p_buffer );
    }
    else
    {
        p_buffer->end_date = p_buffer->start_date
                                + (mtime_t)(p_buffer->i_nb_samples * 1000000)
                                    / p_input->input.i_rate;
    }

    /* If the buffer is too early, wait a while. */
    mwait( p_buffer->start_date - AOUT_MAX_PREPARE_TIME );

    aout_InputPlay( p_aout, p_input, p_buffer );

    /* Run the mixer if it is able to run. */
    aout_MixerRun( p_aout );
}


/*
 * Formats management (internal)
 */

/*****************************************************************************
 * aout_FormatPrepare : compute the number of bytes per frame & frame length
 *****************************************************************************/
void aout_FormatPrepare( audio_sample_format_t * p_format )
{
    int i_result;

    switch ( p_format->i_format )
    {
    case AOUT_FMT_U8:
    case AOUT_FMT_S8:
        i_result = 1;
        break;

    case AOUT_FMT_U16_LE:
    case AOUT_FMT_U16_BE:
    case AOUT_FMT_S16_LE:
    case AOUT_FMT_S16_BE:
        i_result = 2;
        break;

    case AOUT_FMT_FLOAT32:
    case AOUT_FMT_FIXED32:
        i_result = 4;
        break;

    case AOUT_FMT_SPDIF:
    case AOUT_FMT_A52:
    case AOUT_FMT_DTS:
        /* For these formats the caller has to indicate the parameters
         * by hand. */
        return;

    default:
        i_result = 0; /* will segfault much sooner... */
    }

    p_format->i_bytes_per_frame = i_result * p_format->i_channels;
    p_format->i_frame_length = 1;
}


/*
 * FIFO management (internal) - please understand that solving race conditions
 * is _your_ job, ie. in the audio output you should own the mixer lock
 * before calling any of these functions.
 */

/*****************************************************************************
 * aout_FifoInit : initialize the members of a FIFO
 *****************************************************************************/
void aout_FifoInit( aout_instance_t * p_aout, aout_fifo_t * p_fifo,
                    u32 i_rate )
{
    p_fifo->p_first = NULL;
    p_fifo->pp_last = &p_fifo->p_first;
    aout_DateInit( &p_fifo->end_date, i_rate );
}

/*****************************************************************************
 * aout_FifoPush : push a packet into the FIFO
 *****************************************************************************/
void aout_FifoPush( aout_instance_t * p_aout, aout_fifo_t * p_fifo,
                    aout_buffer_t * p_buffer )
{
    *p_fifo->pp_last = p_buffer;
    p_fifo->pp_last = &p_buffer->p_next;
    *p_fifo->pp_last = NULL;
    /* Enforce the continuity of the stream. */
    if ( aout_DateGet( &p_fifo->end_date ) )
    {
        p_buffer->start_date = aout_DateGet( &p_fifo->end_date );
        p_buffer->end_date = aout_DateIncrement( &p_fifo->end_date,
                                                 p_buffer->i_nb_samples ); 
    }
    else
    {
        aout_DateSet( &p_fifo->end_date, p_buffer->end_date );
    }
}

/*****************************************************************************
 * aout_FifoSet : set end_date and trash all buffers (because they aren't
 * properly dated)
 *****************************************************************************/
void aout_FifoSet( aout_instance_t * p_aout, aout_fifo_t * p_fifo,
                   mtime_t date )
{
    aout_buffer_t * p_buffer;

    aout_DateSet( &p_fifo->end_date, date );
    p_buffer = p_fifo->p_first;
    while ( p_buffer != NULL )
    {
        aout_buffer_t * p_next = p_buffer->p_next;
        aout_BufferFree( p_buffer );
        p_buffer = p_next;
    }
    p_fifo->p_first = NULL;
    p_fifo->pp_last = &p_fifo->p_first;
}

/*****************************************************************************
 * aout_FifoMoveDates : Move forwards or backwards all dates in the FIFO
 *****************************************************************************/
void aout_FifoMoveDates( aout_instance_t * p_aout, aout_fifo_t * p_fifo,
                         mtime_t difference )
{
    aout_buffer_t * p_buffer;

    aout_DateMove( &p_fifo->end_date, difference );
    p_buffer = p_fifo->p_first;
    while ( p_buffer != NULL )
    {
        p_buffer->start_date += difference;
        p_buffer->end_date += difference;
        p_buffer = p_buffer->p_next;
    }
}

/*****************************************************************************
 * aout_FifoNextStart : return the current end_date
 *****************************************************************************/
mtime_t aout_FifoNextStart( aout_instance_t * p_aout, aout_fifo_t * p_fifo )
{
    return aout_DateGet( &p_fifo->end_date );
}

/*****************************************************************************
 * aout_FifoPop : get the next buffer out of the FIFO
 *****************************************************************************/
aout_buffer_t * aout_FifoPop( aout_instance_t * p_aout, aout_fifo_t * p_fifo )
{
    aout_buffer_t * p_buffer;
    p_buffer = p_fifo->p_first;
    if ( p_buffer == NULL ) return NULL;
    p_fifo->p_first = p_buffer->p_next;
    if ( p_fifo->p_first == NULL )
    {
        p_fifo->pp_last = &p_fifo->p_first;
    }

    return p_buffer;
}

/*****************************************************************************
 * aout_FifoDestroy : destroy a FIFO and its buffers
 *****************************************************************************/
void aout_FifoDestroy( aout_instance_t * p_aout, aout_fifo_t * p_fifo )
{
    aout_buffer_t * p_buffer;

    p_buffer = p_fifo->p_first;
    while ( p_buffer != NULL )
    {
        aout_buffer_t * p_next = p_buffer->p_next;
        aout_BufferFree( p_buffer );
        p_buffer = p_next;
    }
}


/*
 * Date management (internal and external)
 */

/*****************************************************************************
 * aout_DateInit : set the divider of an audio_date_t
 *****************************************************************************/
void aout_DateInit( audio_date_t * p_date, u32 i_divider )
{
    p_date->date = 0;
    p_date->i_divider = i_divider;
    p_date->i_remainder = 0;
}

/*****************************************************************************
 * aout_DateSet : set the date of an audio_date_t
 *****************************************************************************/
void aout_DateSet( audio_date_t * p_date, mtime_t new_date )
{
    p_date->date = new_date;
    p_date->i_remainder = 0;
}

/*****************************************************************************
 * aout_DateMove : move forwards or backwards the date of an audio_date_t
 *****************************************************************************/
void aout_DateMove( audio_date_t * p_date, mtime_t difference )
{
    p_date->date += difference;
}

/*****************************************************************************
 * aout_DateGet : get the date of an audio_date_t
 *****************************************************************************/
mtime_t aout_DateGet( const audio_date_t * p_date )
{
    return p_date->date;
}

/*****************************************************************************
 * aout_DateIncrement : increment the date and return the result, taking
 * into account rounding errors
 *****************************************************************************/
mtime_t aout_DateIncrement( audio_date_t * p_date, u32 i_nb_samples )
{
    mtime_t i_dividend = (mtime_t)i_nb_samples * 1000000;
    p_date->date += i_dividend / p_date->i_divider;
    p_date->i_remainder += i_dividend % p_date->i_divider;
    if ( p_date->i_remainder >= p_date->i_divider )
    {
        /* This is Bresenham algorithm. */
        p_date->date++;
        p_date->i_remainder -= p_date->i_divider;
    }
    return p_date->date;
}

