/*****************************************************************************
 * trivial.c : trivial mixer plug-in (1 input, no downmixing)
 *****************************************************************************
 * Copyright (C) 2002 VideoLAN
 * $Id: trivial.c,v 1.3 2002/08/11 22:36:35 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 <errno.h>
#include <stdlib.h>                                      /* malloc(), free() */
#include <string.h>

#include <vlc/vlc.h>
#include "audio_output.h"
#include "aout_internal.h"

/*****************************************************************************
 * Local prototypes
 *****************************************************************************/
static int  Create    ( vlc_object_t * );

static void DoWork    ( aout_instance_t *, aout_buffer_t * );

/*****************************************************************************
 * Module descriptor
 *****************************************************************************/
vlc_module_begin();
    set_description( _("trivial aout mixer module") );
    set_capability( "audio mixer", 1 );
    add_shortcut( "trivial" );
    set_callbacks( Create, NULL );
vlc_module_end();

/*****************************************************************************
 * Create: allocate trivial mixer
 *****************************************************************************/
static int Create( vlc_object_t *p_this )
{
    aout_instance_t * p_aout = (aout_instance_t *)p_this;

    if ( p_aout->mixer.output.i_format != AOUT_FMT_FLOAT32
          && p_aout->mixer.output.i_format != AOUT_FMT_FIXED32 )
    {
        return -1;
    }

    p_aout->mixer.pf_do_work = DoWork;

    return 0;
}

/*****************************************************************************
 * SparseCopy: trivially downmix or upmix a buffer
 *****************************************************************************/
static void SparseCopy( u32 * p_dest, const u32 * p_src, size_t i_len,
                        int i_output_stride, int i_input_stride )
{
    int i;
    for ( i = 0; i < i_len; i++ )
    {
        int j;
        for ( j = 0; j < i_output_stride; j++ )
        {
            p_dest[j] = p_src[j];
        }
        p_src += i_input_stride;
        p_dest += i_output_stride;
    }
}

/*****************************************************************************
 * DoWork: mix a new output buffer
 *****************************************************************************/
static void DoWork( aout_instance_t * p_aout, aout_buffer_t * p_buffer )
{
    aout_input_t * p_input = p_aout->pp_inputs[0];

    if ( p_input->input.i_channels == p_aout->mixer.output.i_channels )
    {
        int i_nb_bytes = p_buffer->i_nb_samples * sizeof(u32)
                          * p_input->input.i_channels;
        byte_t * p_in = (p_input->p_first_byte_to_mix == NULL) ?
                        p_input->fifo.p_first->p_buffer :
                        p_input->p_first_byte_to_mix;
        byte_t * p_out = p_buffer->p_buffer;

        for ( ; ; )
        {
            ptrdiff_t i_available_bytes = (p_input->fifo.p_first->p_buffer
                                           - p_in)
                                           + p_input->fifo.p_first->i_nb_samples
                                              * sizeof(u32)
                                              * p_input->input.i_channels;

            if ( i_available_bytes < i_nb_bytes )
            {
                aout_buffer_t * p_old_buffer;

                if ( i_available_bytes > 0 )
                    p_aout->p_vlc->pf_memcpy( p_out, p_in, i_available_bytes );
                i_nb_bytes -= i_available_bytes;
                p_out += i_available_bytes;

                /* Next buffer */
                p_old_buffer = aout_FifoPop( p_aout, &p_input->fifo );
                aout_BufferFree( p_old_buffer );
                if ( p_input->fifo.p_first == NULL )
                {
                    msg_Err( p_aout, "internal amix error" );
                    return;
                }
                p_in = p_input->fifo.p_first->p_buffer;
            }
            else
            {
                p_aout->p_vlc->pf_memcpy( p_out, p_in, i_nb_bytes );
                p_input->p_first_byte_to_mix = p_in + i_nb_bytes;
                break;
            }
        }
    }
    else
    {
        /* Downmixing or upmixing. */
        int i_nb_samples = p_buffer->i_nb_samples;
        u32 * p_in = (p_input->p_first_byte_to_mix == NULL) ?
                     (u32 *)p_input->fifo.p_first->p_buffer :
                     (u32 *)p_input->p_first_byte_to_mix;
        u32 * p_out = (u32 *)p_buffer->p_buffer;


        if ( p_input->input.i_channels < p_aout->mixer.output.i_channels )
        {
            /* Zero out the destination buffer, to avoid static on unavailable
             * channels. */
            memset( p_buffer->p_buffer, 0,
                    p_buffer->i_nb_samples * sizeof(u32)
                     * p_aout->mixer.output.i_channels );
        }

        for ( ; ; )
        {
            ptrdiff_t i_available_bytes = (p_input->fifo.p_first->p_buffer
                                           - (byte_t *)p_in)
                                           + p_input->fifo.p_first->i_nb_samples
                                              * sizeof(u32)
                                              * p_input->input.i_channels;
            int i_available_samples = i_available_bytes
                                       / p_input->input.i_channels
                                       / sizeof(u32);

            if ( i_available_samples < i_nb_samples )
            {
                aout_buffer_t * p_old_buffer;

                if ( i_available_samples > 0 )
                    SparseCopy( p_out, p_in, i_available_samples,
                                p_aout->mixer.output.i_channels,
                                p_input->input.i_channels );
                i_nb_samples -= i_available_samples;
                p_out += i_available_samples * p_aout->mixer.output.i_channels;

                /* Next buffer */
                p_old_buffer = aout_FifoPop( p_aout, &p_input->fifo );
                aout_BufferFree( p_old_buffer );
                if ( p_input->fifo.p_first == NULL )
                {
                    msg_Err( p_aout, "internal amix error" );
                    return;
                }
                p_in = (u32 *)p_input->fifo.p_first->p_buffer;
            }
            else
            {
                SparseCopy( p_out, p_in, i_nb_samples,
                            p_aout->mixer.output.i_channels,
                            p_input->input.i_channels );
                p_input->p_first_byte_to_mix = (byte_t *)p_in
                               + i_nb_samples * p_input->input.i_channels
                                  * sizeof(u32);
                break;
            }
        }
    }
}

