1 files changed, 290 insertions, 0 deletions
diff --git a/plugins/gme/game-music-emu-0.6pre/gme/Multi_Buffer.cpp b/plugins/gme/game-music-emu-0.6pre/gme/Multi_Buffer.cpp
new file mode 100644
index 00000000..c23b633e
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+++ b/plugins/gme/game-music-emu-0.6pre/gme/Multi_Buffer.cpp
@@ -0,0 +1,290 @@
+// Blip_Buffer 0.4.0. http://www.slack.net/~ant/
+
+#include "Multi_Buffer.h"
+
+/* Copyright (C) 2003-2008 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"
+
+Multi_Buffer::Multi_Buffer( int spf ) : samples_per_frame_( spf )
+{
+	length_                 = 0;
+	sample_rate_            = 0;
+	channels_changed_count_ = 1;
+	channel_types_          = NULL;
+	channel_count_          = 0;
+	immediate_removal_      = true;
+}
+
+Multi_Buffer::channel_t Multi_Buffer::channel( int /*index*/ )
+{
+	channel_t ch;
+	ch.center = ch.left = ch.right = NULL;
+	return ch;
+}
+
+// Silent_Buffer
+
+Silent_Buffer::Silent_Buffer() : Multi_Buffer( 1 ) // 0 channels would probably confuse
+{
+	// TODO: better to use empty Blip_Buffer so caller never has to check for NULL?
+	chan.left   = NULL;
+	chan.center = NULL;
+	chan.right  = NULL;
+}
+
+// Mono_Buffer
+
+Mono_Buffer::Mono_Buffer() : Multi_Buffer( 1 )
+{
+	chan.center = &buf;
+	chan.left   = &buf;
+	chan.right  = &buf;
+}
+
+Mono_Buffer::~Mono_Buffer() { }
+
+blargg_err_t Mono_Buffer::set_sample_rate( int rate, int msec )
+{
+	RETURN_ERR( buf.set_sample_rate( rate, msec ) );
+	return Multi_Buffer::set_sample_rate( buf.sample_rate(), buf.length() );
+}
+
+
+// Tracked_Blip_Buffer
+
+int const blip_buffer_extra = 32; // TODO: explain why this value
+
+Tracked_Blip_Buffer::Tracked_Blip_Buffer()
+{
+	last_non_silence = 0;
+}
+
+void Tracked_Blip_Buffer::clear()
+{
+	last_non_silence = 0;
+	Blip_Buffer::clear();
+}
+
+void Tracked_Blip_Buffer::end_frame( blip_time_t t )
+{
+	Blip_Buffer::end_frame( t );
+	if ( modified() )
+	{
+		clear_modified();
+		last_non_silence = samples_avail() + blip_buffer_extra;
+	}
+}
+
+unsigned Tracked_Blip_Buffer::non_silent() const
+{
+	return last_non_silence | unsettled();
+}
+
+inline void Tracked_Blip_Buffer::remove_( int n )
+{
+	if ( (last_non_silence -= n) < 0 )
+		last_non_silence = 0;
+}
+
+void Tracked_Blip_Buffer::remove_silence( int n )
+{
+	remove_( n );
+	Blip_Buffer::remove_silence( n );
+}
+
+void Tracked_Blip_Buffer::remove_samples( int n )
+{
+	remove_( n );
+	Blip_Buffer::remove_samples( n );
+}
+
+void Tracked_Blip_Buffer::remove_all_samples()
+{
+	int avail = samples_avail();
+	if ( !non_silent() )
+		remove_silence( avail );
+	else
+		remove_samples( avail );
+}
+
+int Tracked_Blip_Buffer::read_samples( blip_sample_t out [], int count )
+{
+	count = Blip_Buffer::read_samples( out, count );
+	remove_( count );
+	return count;
+}
+
+// Stereo_Buffer
+
+int const stereo = 2;
+
+Stereo_Buffer::Stereo_Buffer() : Multi_Buffer( 2 )
+{
+	chan.center = mixer.bufs [2] = &bufs [2];
+	chan.left   = mixer.bufs [0] = &bufs [0];
+	chan.right  = mixer.bufs [1] = &bufs [1];
+	mixer.samples_read = 0;
+}
+
+Stereo_Buffer::~Stereo_Buffer() { }
+
+blargg_err_t Stereo_Buffer::set_sample_rate( int rate, int msec )
+{
+	mixer.samples_read = 0;
+	for ( int i = bufs_size; --i >= 0; )
+		RETURN_ERR( bufs [i].set_sample_rate( rate, msec ) );
+	return Multi_Buffer::set_sample_rate( bufs [0].sample_rate(), bufs [0].length() );
+}
+
+void Stereo_Buffer::clock_rate( int rate )
+{
+	for ( int i = bufs_size; --i >= 0; )
+		bufs [i].clock_rate( rate );
+}
+
+void Stereo_Buffer::bass_freq( int bass )
+{
+	for ( int i = bufs_size; --i >= 0; )
+		bufs [i].bass_freq( bass );
+}
+
+void Stereo_Buffer::clear()
+{
+	mixer.samples_read = 0;
+	for ( int i = bufs_size; --i >= 0; )
+		bufs [i].clear();
+}
+
+void Stereo_Buffer::end_frame( blip_time_t time )
+{
+	for ( int i = bufs_size; --i >= 0; )
+		bufs [i].end_frame( time );
+}
+
+int Stereo_Buffer::read_samples( blip_sample_t out [], int out_size )
+{
+	require( (out_size & 1) == 0 ); // must read an even number of samples
+	out_size = min( out_size, samples_avail() );
+
+	int pair_count = int (out_size >> 1);
+	if ( pair_count )
+	{
+		mixer.read_pairs( out, pair_count );
+		
+		if ( samples_avail() <= 0 || immediate_removal() )
+		{
+			for ( int i = bufs_size; --i >= 0; )
+			{
+				buf_t& b = bufs [i];
+				// TODO: might miss non-silence settling since it checks END of last read
+				if ( !b.non_silent() )
+					b.remove_silence( mixer.samples_read );
+				else
+					b.remove_samples( mixer.samples_read );
+			}
+			mixer.samples_read = 0;
+		}
+	}
+	return out_size;
+}
+
+
+// Stereo_Mixer
+
+// mixers use a single index value to improve performance on register-challenged processors
+// offset goes from negative to zero
+
+void Stereo_Mixer::read_pairs( blip_sample_t out [], int count )
+{
+	// TODO: if caller never marks buffers as modified, uses mono
+	// except that buffer isn't cleared, so caller can encounter
+	// subtle problems and not realize the cause.
+	samples_read += count;
+	if ( bufs [0]->non_silent() | bufs [1]->non_silent() )
+		mix_stereo( out, count );
+	else
+		mix_mono( out, count );
+}
+
+void Stereo_Mixer::mix_mono( blip_sample_t out_ [], int count )
+{
+	int const bass = bufs [2]->highpass_shift();
+	Blip_Buffer::delta_t const* center = bufs [2]->read_pos() + samples_read;
+	int center_sum = bufs [2]->integrator();
+	
+	typedef blip_sample_t stereo_blip_sample_t [stereo];
+	stereo_blip_sample_t* BLARGG_RESTRICT out = (stereo_blip_sample_t*) out_ + count;
+	int offset = -count;
+	do
+	{
+		int s = center_sum >> bufs [2]->delta_bits;
+		
+		center_sum -= center_sum >> bass;
+		center_sum += center [offset];
+		
+		BLIP_CLAMP( s, s );
+		
+		out [offset] [0] = (blip_sample_t) s;
+		out [offset] [1] = (blip_sample_t) s;
+	}
+	while ( ++offset );
+	
+	bufs [2]->set_integrator( center_sum );
+}
+
+void Stereo_Mixer::mix_stereo( blip_sample_t out_ [], int count )
+{
+	blip_sample_t* BLARGG_RESTRICT out = out_ + count * stereo;
+	
+	// do left + center and right + center separately to reduce register load
+	Tracked_Blip_Buffer* const* buf = &bufs [2];
+	while ( true ) // loop runs twice
+	{
+		--buf;
+		--out;
+		
+		int const bass = bufs [2]->highpass_shift();
+		Blip_Buffer::delta_t const* side = (*buf)->read_pos() + samples_read;
+		Blip_Buffer::delta_t const* center = bufs [2]->read_pos() + samples_read;
+	
+		int side_sum = (*buf)->integrator();
+		int center_sum = bufs [2]->integrator();
+		
+		int offset = -count;
+		do
+		{
+			int s = (center_sum + side_sum) >> Blip_Buffer::delta_bits;
+			
+			side_sum   -= side_sum   >> bass;
+			center_sum -= center_sum >> bass;
+			
+			side_sum   += side   [offset];
+			center_sum += center [offset];
+			
+			BLIP_CLAMP( s, s );
+			
+			++offset; // before write since out is decremented to slightly before end
+			out [offset * stereo] = (blip_sample_t) s;
+		}
+		while ( offset );
+		
+		(*buf)->set_integrator( side_sum );
+		
+		if ( buf != bufs )
+			continue;
+		
+		// only end center once
+		bufs [2]->set_integrator( center_sum );
+		break;
+	}
+}