rlm@1: // Blip_Buffer 0.4.1. http://www.slack.net/~ant/
rlm@1: 
rlm@1: #include "Blip_Buffer.h"
rlm@1: 
rlm@1: #include <assert.h>
rlm@1: #include <limits.h>
rlm@1: #include <string.h>
rlm@1: #include <stdlib.h>
rlm@1: #include <math.h>
rlm@1: 
rlm@1: /* Copyright (C) 2003-2007 Shay Green. This module is free software; you
rlm@1: can redistribute it and/or modify it under the terms of the GNU Lesser
rlm@1: General Public License as published by the Free Software Foundation; either
rlm@1: version 2.1 of the License, or (at your option) any later version. This
rlm@1: module is distributed in the hope that it will be useful, but WITHOUT ANY
rlm@1: WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
rlm@1: FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
rlm@1: details. You should have received a copy of the GNU Lesser General Public
rlm@1: License along with this module; if not, write to the Free Software Foundation,
rlm@1: Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */
rlm@1: 
rlm@1: // TODO: use scoped for variables in treble_eq()
rlm@1: 
rlm@1: #ifdef BLARGG_ENABLE_OPTIMIZER
rlm@1: 	#include BLARGG_ENABLE_OPTIMIZER
rlm@1: #endif
rlm@1: 
rlm@1: int const silent_buf_size = 1; // size used for Silent_Blip_Buffer
rlm@1: 
rlm@1: Blip_Buffer::Blip_Buffer()
rlm@1: {
rlm@1: 	factor_       = LONG_MAX;
rlm@1: 	buffer_       = 0;
rlm@1: 	buffer_size_  = 0;
rlm@1: 	sample_rate_  = 0;
rlm@1: 	bass_shift_   = 0;
rlm@1: 	clock_rate_   = 0;
rlm@1: 	bass_freq_    = 16;
rlm@1: 	length_       = 0;
rlm@1: 
rlm@1: 	// assumptions code makes about implementation-defined features
rlm@1: 	#ifndef NDEBUG
rlm@1: 		// right shift of negative value preserves sign
rlm@1: 		buf_t_ i = -0x7FFFFFFE;
rlm@1: 		assert( (i >> 1) == -0x3FFFFFFF );
rlm@1: 
rlm@1: 		// casting to short truncates to 16 bits and sign-extends
rlm@1: 		i = 0x18000;
rlm@1: 		assert( (short) i == -0x8000 );
rlm@1: 	#endif
rlm@1: 
rlm@1: 	clear();
rlm@1: }
rlm@1: 
rlm@1: Blip_Buffer::~Blip_Buffer()
rlm@1: {
rlm@1: 	if ( buffer_size_ != silent_buf_size )
rlm@1: 		free( buffer_ );
rlm@1: }
rlm@1: 
rlm@1: Silent_Blip_Buffer::Silent_Blip_Buffer()
rlm@1: {
rlm@1: 	factor_      = 0;
rlm@1: 	buffer_      = buf;
rlm@1: 	buffer_size_ = silent_buf_size;
rlm@1: 	clear();
rlm@1: }
rlm@1: 
rlm@1: void Blip_Buffer::clear( int entire_buffer )
rlm@1: {
rlm@1: 	offset_       = 0;
rlm@1: 	reader_accum_ = 0;
rlm@1: 	modified_     = 0;
rlm@1: 	if ( buffer_ )
rlm@1: 	{
rlm@1: 		long count = (entire_buffer ? buffer_size_ : samples_avail());
rlm@1: 		memset( buffer_, 0, (count + blip_buffer_extra_) * sizeof (buf_t_) );
rlm@1: 	}
rlm@1: }
rlm@1: 
rlm@1: Blip_Buffer::blargg_err_t Blip_Buffer::set_sample_rate( long new_rate, int msec )
rlm@1: {
rlm@1: 	if ( buffer_size_ == silent_buf_size )
rlm@1: 	{
rlm@1: 		assert( 0 );
rlm@1: 		return "Internal (tried to resize Silent_Blip_Buffer)";
rlm@1: 	}
rlm@1: 
rlm@1: 	// start with maximum length that resampled time can represent
rlm@1: 	long new_size = (ULONG_MAX >> BLIP_BUFFER_ACCURACY) - blip_buffer_extra_ - 64;
rlm@1: 	if ( msec != blip_max_length )
rlm@1: 	{
rlm@1: 		long s = (new_rate * (msec + 1) + 999) / 1000;
rlm@1: 		if ( s < new_size )
rlm@1: 			new_size = s;
rlm@1: 		else
rlm@1: 			assert( 0 ); // fails if requested buffer length exceeds limit
rlm@1: 	}
rlm@1: 
rlm@1: 	if ( buffer_size_ != new_size )
rlm@1: 	{
rlm@1: 		void* p = realloc( buffer_, (new_size + blip_buffer_extra_) * sizeof *buffer_ );
rlm@1: 		if ( !p )
rlm@1: 			return "Out of memory";
rlm@1: 		buffer_ = (buf_t_*) p;
rlm@1: 	}
rlm@1: 
rlm@1: 	buffer_size_ = new_size;
rlm@1: 	assert( buffer_size_ != silent_buf_size ); // size should never happen to match this
rlm@1: 
rlm@1: 	// update things based on the sample rate
rlm@1: 	sample_rate_ = new_rate;
rlm@1: 	length_ = new_size * 1000 / new_rate - 1;
rlm@1: 	if ( msec )
rlm@1: 		assert( length_ == msec ); // ensure length is same as that passed in
rlm@1: 
rlm@1: 	// update these since they depend on sample rate
rlm@1: 	if ( clock_rate_ )
rlm@1: 		clock_rate( clock_rate_ );
rlm@1: 	bass_freq( bass_freq_ );
rlm@1: 
rlm@1: 	clear();
rlm@1: 
rlm@1: 	return 0; // success
rlm@1: }
rlm@1: 
rlm@1: blip_resampled_time_t Blip_Buffer::clock_rate_factor( long rate ) const
rlm@1: {
rlm@1: 	double ratio = (double) sample_rate_ / rate;
rlm@1: 	blip_long factor = (blip_long) floor( ratio * (1L << BLIP_BUFFER_ACCURACY) + 0.5 );
rlm@1: 	assert( factor > 0 || !sample_rate_ ); // fails if clock/output ratio is too large
rlm@1: 	return (blip_resampled_time_t) factor;
rlm@1: }
rlm@1: 
rlm@1: void Blip_Buffer::bass_freq( int freq )
rlm@1: {
rlm@1: 	bass_freq_ = freq;
rlm@1: 	int shift = 31;
rlm@1: 	if ( freq > 0 )
rlm@1: 	{
rlm@1: 		shift = 13;
rlm@1: 		long f = (freq << 16) / sample_rate_;
rlm@1: 		while ( (f >>= 1) && --shift ) { }
rlm@1: 	}
rlm@1: 	bass_shift_ = shift;
rlm@1: }
rlm@1: 
rlm@1: void Blip_Buffer::end_frame( blip_time_t t )
rlm@1: {
rlm@1: 	offset_ += t * factor_;
rlm@1: 	assert( samples_avail() <= (long) buffer_size_ ); // fails if time is past end of buffer
rlm@1: }
rlm@1: 
rlm@1: long Blip_Buffer::count_samples( blip_time_t t ) const
rlm@1: {
rlm@1: 	blip_resampled_time_t last_sample  = resampled_time( t ) >> BLIP_BUFFER_ACCURACY;
rlm@1: 	blip_resampled_time_t first_sample = offset_ >> BLIP_BUFFER_ACCURACY;
rlm@1: 	return long (last_sample - first_sample);
rlm@1: }
rlm@1: 
rlm@1: blip_time_t Blip_Buffer::count_clocks( long count ) const
rlm@1: {
rlm@1: 	if ( !factor_ )
rlm@1: 	{
rlm@1: 		assert( 0 ); // sample rate and clock rates must be set first
rlm@1: 		return 0;
rlm@1: 	}
rlm@1: 
rlm@1: 	if ( count > buffer_size_ )
rlm@1: 		count = buffer_size_;
rlm@1: 	blip_resampled_time_t time = (blip_resampled_time_t) count << BLIP_BUFFER_ACCURACY;
rlm@1: 	return (blip_time_t) ((time - offset_ + factor_ - 1) / factor_);
rlm@1: }
rlm@1: 
rlm@1: void Blip_Buffer::remove_samples( long count )
rlm@1: {
rlm@1: 	if ( count )
rlm@1: 	{
rlm@1: 		remove_silence( count );
rlm@1: 
rlm@1: 		// copy remaining samples to beginning and clear old samples
rlm@1: 		long remain = samples_avail() + blip_buffer_extra_;
rlm@1: 		memmove( buffer_, buffer_ + count, remain * sizeof *buffer_ );
rlm@1: 		memset( buffer_ + remain, 0, count * sizeof *buffer_ );
rlm@1: 	}
rlm@1: }
rlm@1: 
rlm@1: // Blip_Synth_
rlm@1: 
rlm@1: Blip_Synth_Fast_::Blip_Synth_Fast_()
rlm@1: {
rlm@1: 	buf          = 0;
rlm@1: 	last_amp     = 0;
rlm@1: 	delta_factor = 0;
rlm@1: }
rlm@1: 
rlm@1: void Blip_Synth_Fast_::volume_unit( double new_unit )
rlm@1: {
rlm@1: 	delta_factor = int (new_unit * (1L << blip_sample_bits) + 0.5);
rlm@1: }
rlm@1: 
rlm@1: #if !BLIP_BUFFER_FAST
rlm@1: 
rlm@1: Blip_Synth_::Blip_Synth_( short* p, int w ) :
rlm@1: 	impulses( p ),
rlm@1: 	width( w )
rlm@1: {
rlm@1: 	volume_unit_ = 0.0;
rlm@1: 	kernel_unit  = 0;
rlm@1: 	buf          = 0;
rlm@1: 	last_amp     = 0;
rlm@1: 	delta_factor = 0;
rlm@1: }
rlm@1: 
rlm@1: #undef PI
rlm@1: #define PI 3.1415926535897932384626433832795029
rlm@1: 
rlm@1: static void gen_sinc( float* out, int count, double oversample, double treble, double cutoff )
rlm@1: {
rlm@1: 	if ( cutoff >= 0.999 )
rlm@1: 		cutoff = 0.999;
rlm@1: 
rlm@1: 	if ( treble < -300.0 )
rlm@1: 		treble = -300.0;
rlm@1: 	if ( treble > 5.0 )
rlm@1: 		treble = 5.0;
rlm@1: 
rlm@1: 	double const maxh = 4096.0;
rlm@1: 	double const rolloff = pow( 10.0, 1.0 / (maxh * 20.0) * treble / (1.0 - cutoff) );
rlm@1: 	double const pow_a_n = pow( rolloff, maxh - maxh * cutoff );
rlm@1: 	double const to_angle = PI / 2 / maxh / oversample;
rlm@1: 	for ( int i = 0; i < count; i++ )
rlm@1: 	{
rlm@1: 		double angle = ((i - count) * 2 + 1) * to_angle;
rlm@1: 		double c = rolloff * cos( (maxh - 1.0) * angle ) - cos( maxh * angle );
rlm@1: 		double cos_nc_angle = cos( maxh * cutoff * angle );
rlm@1: 		double cos_nc1_angle = cos( (maxh * cutoff - 1.0) * angle );
rlm@1: 		double cos_angle = cos( angle );
rlm@1: 
rlm@1: 		c = c * pow_a_n - rolloff * cos_nc1_angle + cos_nc_angle;
rlm@1: 		double d = 1.0 + rolloff * (rolloff - cos_angle - cos_angle);
rlm@1: 		double b = 2.0 - cos_angle - cos_angle;
rlm@1: 		double a = 1.0 - cos_angle - cos_nc_angle + cos_nc1_angle;
rlm@1: 
rlm@1: 		out [i] = (float) ((a * d + c * b) / (b * d)); // a / b + c / d
rlm@1: 	}
rlm@1: }
rlm@1: 
rlm@1: void blip_eq_t::generate( float* out, int count ) const
rlm@1: {
rlm@1: 	// lower cutoff freq for narrow kernels with their wider transition band
rlm@1: 	// (8 points->1.49, 16 points->1.15)
rlm@1: 	double oversample = blip_res * 2.25 / count + 0.85;
rlm@1: 	double half_rate = sample_rate * 0.5;
rlm@1: 	if ( cutoff_freq )
rlm@1: 		oversample = half_rate / cutoff_freq;
rlm@1: 	double cutoff = rolloff_freq * oversample / half_rate;
rlm@1: 
rlm@1: 	gen_sinc( out, count, blip_res * oversample, treble, cutoff );
rlm@1: 
rlm@1: 	// apply (half of) hamming window
rlm@1: 	double to_fraction = PI / (count - 1);
rlm@1: 	for ( int i = count; i--; )
rlm@1: 		out [i] *= 0.54f - 0.46f * (float) cos( i * to_fraction );
rlm@1: }
rlm@1: 
rlm@1: void Blip_Synth_::adjust_impulse()
rlm@1: {
rlm@1: 	// sum pairs for each phase and add error correction to end of first half
rlm@1: 	int const size = impulses_size();
rlm@1: 	for ( int p = blip_res; p-- >= blip_res / 2; )
rlm@1: 	{
rlm@1: 		int p2 = blip_res - 2 - p;
rlm@1: 		long error = kernel_unit;
rlm@1: 		for ( int i = 1; i < size; i += blip_res )
rlm@1: 		{
rlm@1: 			error -= impulses [i + p ];
rlm@1: 			error -= impulses [i + p2];
rlm@1: 		}
rlm@1: 		if ( p == p2 )
rlm@1: 			error /= 2; // phase = 0.5 impulse uses same half for both sides
rlm@1: 		impulses [size - blip_res + p] += (short) error;
rlm@1: 		//printf( "error: %ld\n", error );
rlm@1: 	}
rlm@1: 
rlm@1: 	//for ( int i = blip_res; i--; printf( "\n" ) )
rlm@1: 	//  for ( int j = 0; j < width / 2; j++ )
rlm@1: 	//      printf( "%5ld,", impulses [j * blip_res + i + 1] );
rlm@1: }
rlm@1: 
rlm@1: void Blip_Synth_::treble_eq( blip_eq_t const& eq )
rlm@1: {
rlm@1: 	float fimpulse [blip_res / 2 * (blip_widest_impulse_ - 1) + blip_res * 2];
rlm@1: 
rlm@1: 	int const half_size = blip_res / 2 * (width - 1);
rlm@1: 	eq.generate( &fimpulse [blip_res], half_size );
rlm@1: 
rlm@1: 	int i;
rlm@1: 
rlm@1: 	// need mirror slightly past center for calculation
rlm@1: 	for ( i = blip_res; i--; )
rlm@1: 		fimpulse [blip_res + half_size + i] = fimpulse [blip_res + half_size - 1 - i];
rlm@1: 
rlm@1: 	// starts at 0
rlm@1: 	for ( i = 0; i < blip_res; i++ )
rlm@1: 		fimpulse [i] = 0.0f;
rlm@1: 
rlm@1: 	// find rescale factor
rlm@1: 	double total = 0.0;
rlm@1: 	for ( i = 0; i < half_size; i++ )
rlm@1: 		total += fimpulse [blip_res + i];
rlm@1: 
rlm@1: 	//double const base_unit = 44800.0 - 128 * 18; // allows treble up to +0 dB
rlm@1: 	//double const base_unit = 37888.0; // allows treble to +5 dB
rlm@1: 	double const base_unit = 32768.0; // necessary for blip_unscaled to work
rlm@1: 	double rescale = base_unit / 2 / total;
rlm@1: 	kernel_unit = (long) base_unit;
rlm@1: 
rlm@1: 	// integrate, first difference, rescale, convert to int
rlm@1: 	double sum = 0.0;
rlm@1: 	double next = 0.0;
rlm@1: 	int const size = this->impulses_size();
rlm@1: 	for ( i = 0; i < size; i++ )
rlm@1: 	{
rlm@1: 		impulses [i] = (short) (int) floor( (next - sum) * rescale + 0.5 );
rlm@1: 		sum += fimpulse [i];
rlm@1: 		next += fimpulse [i + blip_res];
rlm@1: 	}
rlm@1: 	adjust_impulse();
rlm@1: 
rlm@1: 	// volume might require rescaling
rlm@1: 	double vol = volume_unit_;
rlm@1: 	if ( vol )
rlm@1: 	{
rlm@1: 		volume_unit_ = 0.0;
rlm@1: 		volume_unit( vol );
rlm@1: 	}
rlm@1: }
rlm@1: 
rlm@1: void Blip_Synth_::volume_unit( double new_unit )
rlm@1: {
rlm@1: 	if ( new_unit != volume_unit_ )
rlm@1: 	{
rlm@1: 		// use default eq if it hasn't been set yet
rlm@1: 		if ( !kernel_unit )
rlm@1: 			treble_eq( -8.0 );
rlm@1: 
rlm@1: 		volume_unit_ = new_unit;
rlm@1: 		double factor = new_unit * (1L << blip_sample_bits) / kernel_unit;
rlm@1: 
rlm@1: 		if ( factor > 0.0 )
rlm@1: 		{
rlm@1: 			int shift = 0;
rlm@1: 
rlm@1: 			// if unit is really small, might need to attenuate kernel
rlm@1: 			while ( factor < 2.0 )
rlm@1: 			{
rlm@1: 				shift++;
rlm@1: 				factor *= 2.0;
rlm@1: 			}
rlm@1: 
rlm@1: 			if ( shift )
rlm@1: 			{
rlm@1: 				kernel_unit >>= shift;
rlm@1: 				assert( kernel_unit > 0 ); // fails if volume unit is too low
rlm@1: 
rlm@1: 				// keep values positive to avoid round-towards-zero of sign-preserving
rlm@1: 				// right shift for negative values
rlm@1: 				long offset = 0x8000 + (1 << (shift - 1));
rlm@1: 				long offset2 = 0x8000 >> shift;
rlm@1: 				for ( int i = impulses_size(); i--; )
rlm@1: 					impulses [i] = (short) (int) (((impulses [i] + offset) >> shift) - offset2);
rlm@1: 				adjust_impulse();
rlm@1: 			}
rlm@1: 		}
rlm@1: 		delta_factor = (int) floor( factor + 0.5 );
rlm@1: 		//printf( "delta_factor: %d, kernel_unit: %d\n", delta_factor, kernel_unit );
rlm@1: 	}
rlm@1: }
rlm@1: #endif
rlm@1: 
rlm@1: long Blip_Buffer::read_samples( blip_sample_t* out_, long max_samples, int stereo )
rlm@1: {
rlm@1: 	long count = samples_avail();
rlm@1: 	if ( count > max_samples )
rlm@1: 		count = max_samples;
rlm@1: 
rlm@1: 	if ( count )
rlm@1: 	{
rlm@1: 		int const bass = BLIP_READER_BASS( *this );
rlm@1: 		BLIP_READER_BEGIN( reader, *this );
rlm@1: 		BLIP_READER_ADJ_( reader, count );
rlm@1: 		blip_sample_t* BLIP_RESTRICT out = out_ + count;
rlm@1: 		blip_long offset = (blip_long) -count;
rlm@1: 
rlm@1: 		if ( !stereo )
rlm@1: 		{
rlm@1: 			do
rlm@1: 			{
rlm@1: 				blip_long s = BLIP_READER_READ( reader );
rlm@1: 				BLIP_READER_NEXT_IDX_( reader, bass, offset );
rlm@1: 				BLIP_CLAMP( s, s );
rlm@1: 				out [offset] = (blip_sample_t) s;
rlm@1: 			}
rlm@1: 			while ( ++offset );
rlm@1: 		}
rlm@1: 		else
rlm@1: 		{
rlm@1: 			do
rlm@1: 			{
rlm@1: 				blip_long s = BLIP_READER_READ( reader );
rlm@1: 				BLIP_READER_NEXT_IDX_( reader, bass, offset );
rlm@1: 				BLIP_CLAMP( s, s );
rlm@1: 				out [offset * 2] = (blip_sample_t) s;
rlm@1: 			}
rlm@1: 			while ( ++offset );
rlm@1: 		}
rlm@1: 
rlm@1: 		BLIP_READER_END( reader, *this );
rlm@1: 
rlm@1: 		remove_samples( count );
rlm@1: 	}
rlm@1: 	return count;
rlm@1: }
rlm@1: 
rlm@1: void Blip_Buffer::mix_samples( blip_sample_t const* in, long count )
rlm@1: {
rlm@1: 	if ( buffer_size_ == silent_buf_size )
rlm@1: 	{
rlm@1: 		assert( 0 );
rlm@1: 		return;
rlm@1: 	}
rlm@1: 
rlm@1: 	buf_t_* out = buffer_ + (offset_ >> BLIP_BUFFER_ACCURACY) + blip_widest_impulse_ / 2;
rlm@1: 
rlm@1: 	int const sample_shift = blip_sample_bits - 16;
rlm@1: 	int prev = 0;
rlm@1: 	while ( count-- )
rlm@1: 	{
rlm@1: 		blip_long s = (blip_long) *in++ << sample_shift;
rlm@1: 		*out += s - prev;
rlm@1: 		prev = s;
rlm@1: 		++out;
rlm@1: 	}
rlm@1: 	*out -= prev;
rlm@1: }
rlm@1: 
rlm@1: blip_ulong const subsample_mask = (1L << BLIP_BUFFER_ACCURACY) - 1;
rlm@1: 
rlm@1: void Blip_Buffer::save_state( blip_buffer_state_t* out )
rlm@1: {
rlm@1: 	assert( samples_avail() == 0 );
rlm@1: 	out->offset_       = offset_;
rlm@1: 	out->reader_accum_ = reader_accum_;
rlm@1: 	memcpy( out->buf, &buffer_ [offset_ >> BLIP_BUFFER_ACCURACY], sizeof out->buf );
rlm@1: }
rlm@1: 
rlm@1: void Blip_Buffer::load_state( blip_buffer_state_t const& in )
rlm@1: {
rlm@1: 	clear( false );
rlm@1: 
rlm@1: 	offset_       = in.offset_;
rlm@1: 	reader_accum_ = in.reader_accum_;
rlm@1: 	memcpy( buffer_, in.buf, sizeof in.buf );
rlm@1: }