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// Game_Music_Emu 0.5.5. http://www.slack.net/~ant/
#include "Dual_Resampler.h"
#include <stdlib.h>
#include <string.h>
/* Copyright (C) 2003-2006 Shay Green. This module is free software; you
can redistribute it and/or modify it under the terms of the GNU Lesser
General Public License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version. This
module 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 Lesser General Public License for more
details. You should have received a copy of the GNU Lesser General Public
License along with this module; if not, write to the Free Software Foundation,
Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */
#include "blargg_source.h"
unsigned const resampler_extra = 256;
Dual_Resampler::Dual_Resampler() { }
Dual_Resampler::~Dual_Resampler() { }
blargg_err_t Dual_Resampler::reset( int pairs )
{
// expand allocations a bit
RETURN_ERR( sample_buf.resize( (pairs + (pairs >> 2)) * 2 ) );
resize( pairs );
resampler_size = oversamples_per_frame + (oversamples_per_frame >> 2);
return resampler.buffer_size( resampler_size );
}
void Dual_Resampler::resize( int pairs )
{
int new_sample_buf_size = pairs * 2;
if ( sample_buf_size != new_sample_buf_size )
{
if ( (unsigned) new_sample_buf_size > sample_buf.size() )
{
check( false );
return;
}
sample_buf_size = new_sample_buf_size;
oversamples_per_frame = int (pairs * resampler.ratio()) * 2 + 2;
clear();
}
}
void Dual_Resampler::play_frame_( Blip_Buffer& blip_buf, dsample_t* out )
{
long pair_count = sample_buf_size >> 1;
blip_time_t blip_time = blip_buf.count_clocks( pair_count );
int sample_count = oversamples_per_frame - resampler.written();
int new_count = play_frame( blip_time, sample_count, resampler.buffer() );
assert( new_count < resampler_size );
blip_buf.end_frame( blip_time );
assert( blip_buf.samples_avail() == pair_count );
resampler.write( new_count );
long count = resampler.read( sample_buf.begin(), sample_buf_size );
assert( count == (long) sample_buf_size );
mix_samples( blip_buf, out );
blip_buf.remove_samples( pair_count );
}
void Dual_Resampler::dual_play( long count, dsample_t* out, Blip_Buffer& blip_buf )
{
// empty extra buffer
long remain = sample_buf_size - buf_pos;
if ( remain )
{
if ( remain > count )
remain = count;
count -= remain;
memcpy( out, &sample_buf [buf_pos], remain * sizeof *out );
out += remain;
buf_pos += remain;
}
// entire frames
while ( count >= (long) sample_buf_size )
{
play_frame_( blip_buf, out );
out += sample_buf_size;
count -= sample_buf_size;
}
// extra
if ( count )
{
play_frame_( blip_buf, sample_buf.begin() );
buf_pos = count;
memcpy( out, sample_buf.begin(), count * sizeof *out );
out += count;
}
}
void Dual_Resampler::mix_samples( Blip_Buffer& blip_buf, dsample_t* out )
{
Blip_Reader sn;
int bass = sn.begin( blip_buf );
const dsample_t* in = sample_buf.begin();
for ( int n = sample_buf_size >> 1; n--; )
{
int s = sn.read();
blargg_long l = (blargg_long) in [0] * 2 + s;
if ( (BOOST::int16_t) l != l )
l = 0x7FFF - (l >> 24);
sn.next( bass );
blargg_long r = (blargg_long) in [1] * 2 + s;
if ( (BOOST::int16_t) r != r )
r = 0x7FFF - (r >> 24);
in += 2;
out [0] = l;
out [1] = r;
out += 2;
}
sn.end( blip_buf );
}
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