1 files changed, 225 insertions, 165 deletions

diff --git a/apps/codecs/libgme/multi_buffer.c b/apps/codecs/libgme/multi_buffer.c
index 26cb8cd..554778c 100644
--- a/apps/codecs/libgme/multi_buffer.c
+++ b/apps/codecs/libgme/multi_buffer.c
@@ -1,4 +1,4 @@
-// Blip_Buffer 0.4.1. http://www.slack.net/~ant/
+// Multi_Buffer 0.4.1. http://www.slack.net/~ant/
 
 #include "multi_buffer.h"
 
@@ -15,212 +15,272 @@ Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */
 
 #include "blargg_source.h"
 
-#ifdef BLARGG_ENABLE_OPTIMIZER
-	#include BLARGG_ENABLE_OPTIMIZER
-#endif
-
-// Stereo_Buffer
- 
-void Buffer_init( struct Stereo_Buffer* this )
-{
-	Blip_init( &this->bufs [0] );
-	Blip_init( &this->bufs [1] );
-	Blip_init( &this->bufs [2] );
-			
-	this->chan.center = &this->bufs [0];
-	this->chan.left = &this->bufs [1];
-	this->chan.right = &this->bufs [2];
-	
-	this->length_ = 0;
-	this->sample_rate_ = 0;
-	this->channels_changed_count_ = 1;
-	this->samples_per_frame_ = 2;
+// Tracked_Blip_Buffer
+
+int const blip_buffer_extra = 32; // TODO: explain why this value
+
+void Tracked_init( struct Tracked_Blip_Buffer* this )
+{
+	Blip_init( &this->blip );
+	this->last_non_silence = 0;
 }
 
-blargg_err_t Buffer_set_sample_rate( struct Stereo_Buffer* this, long rate, int msec )
+void Tracked_clear( struct Tracked_Blip_Buffer* this )
 {
-	int i;
-	for ( i = 0; i < buf_count; i++ )
-		RETURN_ERR( Blip_set_sample_rate( &this->bufs[i], rate, msec ) );
-		
-	this->sample_rate_ = Blip_sample_rate( &this->bufs [0] );
-	this->length_ = Blip_length( &this->bufs [0] );
-	return 0;
+	this->last_non_silence = 0;
+	Blip_clear( &this->blip );
 }
 
-void Buffer_clock_rate( struct Stereo_Buffer* this, long rate )
+void Tracked_end_frame( struct Tracked_Blip_Buffer* this, blip_time_t t )
 {
-	int i;
-	for ( i = 0; i < buf_count; i++ )
-		Blip_set_clock_rate( &this->bufs [i], rate );
+	Blip_end_frame( &this->blip, t );
+	if ( this->blip.modified )
+	{
+		this->blip.modified = false;
+		this->last_non_silence = Blip_samples_avail( &this->blip ) + blip_buffer_extra;
+	}
 }
 
-void Buffer_bass_freq( struct Stereo_Buffer* this, int bass )
+unsigned Tracked_non_silent( struct Tracked_Blip_Buffer* this )
 {
-	unsigned i;
-	for ( i = 0; i < buf_count; i++ )
-		Blip_bass_freq( &this->bufs [i], bass );
+	return this->last_non_silence | unsettled( &this->blip );
 }
 
-struct channel_t Buffer_channel( struct Stereo_Buffer* this )
+static inline void remove_( struct Tracked_Blip_Buffer* this, int n )
 {
-	return this->chan;
+	if ( (this->last_non_silence -= n) < 0 )
+		this->last_non_silence = 0;
 }
 
-void Buffer_clear( struct Stereo_Buffer* this )
+void Tracked_remove_silence( struct Tracked_Blip_Buffer* this, int n )
 {
-	this->stereo_added = 0;
-	this->was_stereo   = false;
-	int i;
-	for ( i = 0; i < buf_count; i++ )
-		Blip_clear( &this->bufs [i], 1 );
+	remove_( this, n );
+	Blip_remove_silence( &this->blip, n );
 }
 
-void Buffer_end_frame( struct Stereo_Buffer* this, blip_time_t clock_count )
+void Tracked_remove_samples( struct Tracked_Blip_Buffer* this, int n )
+{
+	remove_( this, n );
+	Blip_remove_samples( &this->blip, n );
+}
+
+void Tracked_remove_all_samples( struct Tracked_Blip_Buffer* this )
+{
+	int avail = Blip_samples_avail( &this->blip );
+	if ( !Tracked_non_silent( this ) )
+		Tracked_remove_silence( this, avail );
+	else
+		Tracked_remove_samples( this, avail );
+}
+
+int Tracked_read_samples( struct Tracked_Blip_Buffer* this, blip_sample_t out [], int count )
+{
+	count = Blip_read_samples( &this->blip, out, count, false );
+	remove_( this, count );
+	return count;
+}
+
+// Stereo_Mixer
+
+// mixers use a single index value to improve performance on register-challenged processors
+// offset goes from negative to zero
+
+void Mixer_init( struct Stereo_Mixer* this )
 {
-	this->stereo_added = 0;
-	unsigned i;
-	for ( i = 0; i < buf_count; i++ )
+	this->samples_read = 0;
+}
+
+static void mix_mono( struct Stereo_Mixer* this, blip_sample_t out_ [], int count )
+{
+	int const bass = this->bufs [2]->blip.bass_shift_;
+	delta_t const* center = this->bufs [2]->blip.buffer_ + this->samples_read;
+	int center_sum = this->bufs [2]->blip.reader_accum_;
+
+	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
 	{
-		this->stereo_added |= Blip_clear_modified( &this->bufs [i] ) << i;
-		Blip_end_frame( &this->bufs [i], clock_count );
+		int s = center_sum >> 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 );
+
+	this->bufs [2]->blip.reader_accum_ = center_sum;
 }
 
-long Buffer_read_samples( struct Stereo_Buffer* this, blip_sample_t* out, long count )
+static void mix_stereo( struct Stereo_Mixer* this, blip_sample_t out_ [], int count )
 {
-	require( !(count & 1) ); // count must be even
-	count = (unsigned) count / 2;
-	
-	long avail = Blip_samples_avail( &this->bufs [0] );
-	if ( count > avail )
-		count = avail;
-	if ( count )
+	blip_sample_t* BLARGG_RESTRICT out = out_ + count * stereo;
+	// do left + center and right + center separately to reduce register load
+	struct Tracked_Blip_Buffer* const* buf = &this->bufs [2];
+	while ( true ) // loop runs twice
 	{
-		int bufs_used = this->stereo_added | this->was_stereo;
-		//dprintf( "%X\n", bufs_used );
-		if ( bufs_used <= 1 )
-		{
-			Buffer_mix_mono( this, out, count );
-			Blip_remove_samples( &this->bufs [0], count );
-			Blip_remove_silence( &this->bufs [1], count );
-			Blip_remove_silence( &this->bufs [2], count );
-		}
-		else if ( bufs_used & 1 )
-		{
-			Buffer_mix_stereo( this, out, count );
-			Blip_remove_samples( &this->bufs [0], count );
-			Blip_remove_samples( &this->bufs [1], count );
-			Blip_remove_samples( &this->bufs [2], count );
-		}
-		else
-		{
-			Buffer_mix_stereo_no_center( this, out, count );
-			Blip_remove_silence( &this->bufs [0], count );
-			Blip_remove_samples( &this->bufs [1], count );
-			Blip_remove_samples( &this->bufs [2], count );
-		}
-		
-		// to do: this might miss opportunities for optimization
-		if ( !Blip_samples_avail( &this->bufs [0] ) )
+		--buf;
+		--out;
+
+		int const bass = this->bufs [2]->blip.bass_shift_;
+		delta_t const* side = (*buf)->blip.buffer_ + this->samples_read;
+		delta_t const* center = this->bufs [2]->blip.buffer_ + this->samples_read;
+
+		int side_sum = (*buf)->blip.reader_accum_;
+		int center_sum = this->bufs [2]->blip.reader_accum_;
+
+		int offset = -count;
+		do
 		{
-			this->was_stereo   = this->stereo_added;
-			this->stereo_added = 0;
+			int s = (center_sum + side_sum) >> 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)->blip.reader_accum_ = side_sum;
+
+		if ( buf != this->bufs )
+			continue;
+
+		// only end center once
+		this->bufs [2]->blip.reader_accum_ = center_sum;
+		break;
 	}
-	
-	return count * 2;
 }
 
-unsigned Buffer_channels_changed_count( struct Stereo_Buffer* this )
+void Mixer_read_pairs( struct Stereo_Mixer* this, blip_sample_t out [], int count )
 {
-	return this->channels_changed_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.
+	this->samples_read += count;
+	if ( Tracked_non_silent( this->bufs [0] ) | Tracked_non_silent( this->bufs [1] ) )
+	mix_stereo( this, out, count );
+	else
+	mix_mono( this, out, count );
 }
 
-void Buffer_channels_changed( struct Stereo_Buffer* this )
+// Multi_Buffer
+
+void Buffer_init( struct Multi_Buffer* this )
 {
-	this->channels_changed_count_++;
+	int const spf = 2;
+
+	Tracked_init( &this->bufs [0] );
+	Tracked_init( &this->bufs [1] );
+	Tracked_init( &this->bufs [2] );
+
+	Mixer_init( &this->mixer );
+
+	this->length_                 = 0;
+	this->sample_rate_            = 0;
+	this->channels_changed_count_ = 1;
+	this->channel_types_          = NULL;
+	this->channel_count_          = 0;
+	this->samples_per_frame_      = spf;
+	this->immediate_removal_      = true;
+
+	this->mixer.bufs [2] = &this->bufs [2];
+	this->mixer.bufs [0] = &this->bufs [0];
+	this->mixer.bufs [1] = &this->bufs [1];
+
+	this->chan.center = &this->bufs [2].blip;
+	this->chan.left   = &this->bufs [0].blip;
+	this->chan.right  = &this->bufs [1].blip;
 }
 
-void Buffer_mix_stereo( struct Stereo_Buffer* this, blip_sample_t* out_, blargg_long count )
+blargg_err_t Buffer_set_sample_rate( struct Multi_Buffer* this, int rate, int msec )
 {
-	blip_sample_t* BLIP_RESTRICT out = out_;
-	int const bass = BLIP_READER_BASS( this->bufs [1] );
-	BLIP_READER_BEGIN( left, this->bufs [1] );
-	BLIP_READER_BEGIN( right, this->bufs [2] );
-	BLIP_READER_BEGIN( center, this->bufs [0] );
-	
-	for ( ; count; --count )
-	{
-		int c = BLIP_READER_READ( center );
-		blargg_long l = c + BLIP_READER_READ( left );
-		blargg_long r = c + BLIP_READER_READ( right );
-		if ( (int16_t) l != l )
-			l = 0x7FFF - (l >> 24);
-		
-		BLIP_READER_NEXT( center, bass );
-		if ( (int16_t) r != r )
-			r = 0x7FFF - (r >> 24);
-		
-		BLIP_READER_NEXT( left, bass );
-		BLIP_READER_NEXT( right, bass );
-		
-		out [0] = l;
-		out [1] = r;
-		out += 2;
-	}
-	
-	BLIP_READER_END( center, this->bufs [0] );
-	BLIP_READER_END( right, this->bufs [2] );
-	BLIP_READER_END( left, this->bufs [1] );
+	int i;
+	for ( i = bufs_size; --i >= 0; )
+		RETURN_ERR( Blip_set_sample_rate( &this->bufs [i].blip, rate, msec ) );
+
+	this->sample_rate_ = Blip_sample_rate( &this->bufs [0].blip );
+	this->length_      = Blip_length( &this->bufs [0].blip );
+	return 0;
 }
 
-void Buffer_mix_stereo_no_center( struct Stereo_Buffer* this, blip_sample_t* out_, blargg_long count )
+void Buffer_clock_rate( struct Multi_Buffer* this, int rate )
 {
-	blip_sample_t* BLIP_RESTRICT out = out_;
-	int const bass = BLIP_READER_BASS( this->bufs [1] );
-	BLIP_READER_BEGIN( left, this->bufs [1] );
-	BLIP_READER_BEGIN( right, this->bufs [2] );
-	
-	for ( ; count; --count )
-	{
-		blargg_long l = BLIP_READER_READ( left );
-		if ( (int16_t) l != l )
-			l = 0x7FFF - (l >> 24);
-		
-		blargg_long r = BLIP_READER_READ( right );
-		if ( (int16_t) r != r )
-			r = 0x7FFF - (r >> 24);
-		
-		BLIP_READER_NEXT( left, bass );
-		BLIP_READER_NEXT( right, bass );
-		
-		out [0] = l;
-		out [1] = r;
-		out += 2;
-	}
-	
-	BLIP_READER_END( right, this->bufs [2] );
-	BLIP_READER_END( left, this->bufs [1] );
+	int i;
+	for ( i = bufs_size; --i >= 0; )
+		Blip_set_clock_rate( &this->bufs [i].blip, rate );
+}
+
+void Buffer_bass_freq( struct Multi_Buffer* this, int bass )
+{
+	int i;
+	for ( i = bufs_size; --i >= 0; )
+		Blip_bass_freq( &this->bufs [i].blip, bass );
+}
+
+blargg_err_t Buffer_set_channel_count( struct Multi_Buffer* this, int n, int const* types )
+{
+	this->channel_count_ = n;
+	this->channel_types_ = types;
+	return 0;
 }
 
-void Buffer_mix_mono( struct Stereo_Buffer* this, blip_sample_t* out_, blargg_long count )
+struct channel_t Buffer_channel( struct Multi_Buffer* this, int i )
 {
-	blip_sample_t* BLIP_RESTRICT out = out_;
-	int const bass = BLIP_READER_BASS( this->bufs [0] );
-	BLIP_READER_BEGIN( center, this->bufs [0] );
-	
-	for ( ; count; --count )
+	(void) i;
+	return this->chan;
+}
+
+void Buffer_clear( struct Multi_Buffer* this )
+{
+	int i;
+	this->mixer.samples_read = 0;
+	for ( i = bufs_size; --i >= 0; )
+		Tracked_clear( &this->bufs [i] );
+}
+
+void Buffer_end_frame( struct Multi_Buffer* this, blip_time_t clock_count )
+{
+    int i;
+    for ( i = bufs_size; --i >= 0; )
+		Tracked_end_frame( &this->bufs [i], clock_count );
+}
+
+int Buffer_read_samples( struct Multi_Buffer* this, blip_sample_t out [], int out_size )
+{
+	require( (out_size & 1) == 0 ); // must read an even number of samples
+	out_size = min( out_size, Buffer_samples_avail( this ) );
+
+	int pair_count = (int) (out_size >> 1);
+	if ( pair_count )
 	{
-		blargg_long s = BLIP_READER_READ( center );
-		if ( (int16_t) s != s )
-			s = 0x7FFF - (s >> 24);
-		
-		BLIP_READER_NEXT( center, bass );
-		out [0] = s;
-		out [1] = s;
-		out += 2;
+		Mixer_read_pairs( &this->mixer, out, pair_count );
+
+		if ( Buffer_samples_avail( this ) <= 0 || this->immediate_removal_ )
+		{
+			int i;
+			for ( i = bufs_size; --i >= 0; )
+			{
+				buf_t* b = &this->bufs [i];
+				// TODO: might miss non-silence settling since it checks END of last read
+				if ( !Tracked_non_silent( b ) )
+					Tracked_remove_silence( b, this->mixer.samples_read );
+				else
+					Tracked_remove_samples( b, this->mixer.samples_read );
+			}
+			this->mixer.samples_read = 0;
+		}
 	}
-	
-	BLIP_READER_END( center, this->bufs [0] );
+
+	return out_size;
 }