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removed unused code
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ekeeke31
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fe055c2a2c
commit
da37355e04
@ -1,165 +0,0 @@
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/* http://www.slack.net/~ant/ */
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#include "blip.h"
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#include <assert.h>
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#include <string.h>
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#include <stdlib.h>
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#include <stddef.h>
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/* Copyright (C) 2003-2008 Shay Green. This module is free software; you
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can redistribute it and/or modify it under the terms of the GNU Lesser
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General Public License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version. This
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module is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
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details. You should have received a copy of the GNU Lesser General Public
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License along with this module; if not, write to the Free Software Foundation,
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Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */
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enum { buf_extra = 2 }; /* extra samples to save past end */
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enum { time_bits = 16 }; /* bits in fraction of fixed-point sample counts */
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enum { time_unit = 1 << time_bits };
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enum { phase_bits = 15 }; /* bits in fraction of deltas in buffer */
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enum { phase_count = 1 << phase_bits };
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enum { phase_shift = time_bits - phase_bits };
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typedef int buf_t; /* type of element in delta buffer */
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struct blip_buffer_t
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{
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int factor; /* clocks to samples conversion factor */
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int offset; /* fractional position of clock 0 in delta buffer */
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int amp; /* current output amplitude (sum of all deltas up to now) */
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int size; /* size of delta buffer */
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buf_t *buf; /* delta buffer, only size elements actually allocated */
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};
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blip_buffer_t* blip_alloc( int clock_rate, int sample_rate, int size )
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{
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/* Allocate space for structure and delta buffer */
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blip_buffer_t* s = (blip_buffer_t*) malloc( sizeof(blip_buffer_t) );
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if (!s) return 0;
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s->buf = (buf_t*) malloc((size + buf_extra) * sizeof (buf_t) );
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if ( s->buf != NULL )
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{
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/* Calculate output:input ratio and convert to fixed-point */
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double ratio = (double) sample_rate / clock_rate;
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s->factor = (int) (ratio * time_unit + 0.5);
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s->size = size;
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blip_clear( s );
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}
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return s;
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}
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void blip_free( blip_buffer_t* s )
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{
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if (s->buf) free(s->buf);
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free( s );
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}
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void blip_clear( blip_buffer_t* s )
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{
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s->offset = 0;
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s->amp = 0;
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memset( s->buf, 0, (s->size + buf_extra) * sizeof (buf_t) );
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}
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void blip_add( blip_buffer_t* s, int clocks, int delta )
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{
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/* Convert to fixed-point time in terms of output samples */
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int fixed_time = clocks * s->factor + s->offset;
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/* Extract whole and fractional parts */
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int index = fixed_time >> time_bits; /* whole */
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int phase = fixed_time >> phase_shift & (phase_count - 1); /* fraction */
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/* Split delta between first and second samples */
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int second = delta * phase;
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int first = delta * phase_count - second;
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/* Be sure index is within buffer */
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assert( index >= 0 && index+1 < s->size + buf_extra );
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/* Add deltas to buffer */
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s->buf [index ] += first;
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s->buf [index+1] += second;
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}
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int blip_clocks_needed( const blip_buffer_t* s, int samples )
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{
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int fixed_needed;
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if ( samples > s->size )
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samples = s->size;
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/* Fixed-point number of samples needed in addition to those in buffer */
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fixed_needed = samples * time_unit - s->offset;
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/* If more are needed, convert to clocks and round up */
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return (fixed_needed <= 0) ? 0 : (fixed_needed - 1) / s->factor + 1;
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}
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void blip_end_frame( blip_buffer_t* s, int clocks )
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{
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s->offset += clocks * s->factor;
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/* Ensure time wasn't past end of buffer */
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assert( blip_samples_avail( s ) <= s->size );
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}
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int blip_samples_avail( const blip_buffer_t* s )
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{
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return s->offset >> time_bits;
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}
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/* Removes n samples from buffer */
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static void remove_samples( blip_buffer_t* s, int n )
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{
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int remain = blip_samples_avail( s ) + buf_extra - n;
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s->offset -= n * time_unit;
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assert( s->offset >= 0 );
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/* Copy remaining samples to beginning of buffer and clear the rest */
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memmove( s->buf, &s->buf [n], remain * sizeof (buf_t) );
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memset( &s->buf [remain], 0, n * sizeof (buf_t) );
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}
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int blip_read_samples( blip_buffer_t* s, short out [], int count, int stereo )
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{
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/* can't read more than available */
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int avail = blip_samples_avail( s );
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if ( count > avail )
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count = avail;
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if ( count )
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{
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/* Sum deltas and write out */
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int i;
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for ( i = 0; i < count; ++i )
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{
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int sample;
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/* Apply slight high-pass filter */
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s->amp -= s->amp >> 9;
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/* Add next delta */
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s->amp += s->buf [i];
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/* Calculate output sample */
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sample = s->amp >> phase_bits;
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/* Keep within 16-bit sample range */
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if ( sample < -32768 ) sample = -32768;
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if ( sample > +32767 ) sample = +32767;
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out [i << stereo] = sample;
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}
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remove_samples( s, count );
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}
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return count;
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}
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@ -1,51 +0,0 @@
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/* Fast sound synthesis buffer for use in real-time emulators of electronic
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sound generator chips like those in early video game consoles. Uses linear
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interpolation. Higher-quality versions are available that use sinc-based
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band-limited synthesis. */
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#ifndef BLIP_H
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#define BLIP_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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/* Creates a new blip_buffer with specified input clock rate, output
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sample rate, and size (in samples), or returns NULL if out of memory. */
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typedef struct blip_buffer_t blip_buffer_t;
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blip_buffer_t* blip_alloc( int clock_rate, int sample_rate, int size );
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/* Frees memory used by a blip_buffer. No effect if NULL is passed. */
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void blip_free( blip_buffer_t* );
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/* Removes all samples and clears buffer. */
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void blip_clear( blip_buffer_t* );
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/* Adds an amplitude transition of delta at specified time in source clocks.
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Delta can be negative. */
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void blip_add( blip_buffer_t*, int time, int delta );
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/* Number of additional clocks needed until n samples will be available.
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If buffer cannot even hold n samples, returns number of clocks until buffer
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becomes full. */
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int blip_clocks_needed( const blip_buffer_t*, int samples_needed );
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/* Ends current time frame of specified duration and make its samples available
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(along with any still-unread samples) for reading with read_samples(), then
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begins a new time frame at the end of the current frame. */
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void blip_end_frame( blip_buffer_t*, int duration );
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/* Number of samples available for reading with read(). */
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int blip_samples_avail( const blip_buffer_t* );
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/* Reads at most n samples out of buffer into out, removing them from from
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the buffer. Returns number of samples actually read and removed. If stereo is
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true, increments 'out' one extra time after writing each sample, to allow
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easy interleving of two channels into a stereo output buffer. */
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int blip_read_samples( blip_buffer_t*, short out [], int n, int stereo );
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#ifdef __cplusplus
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}
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#endif
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#endif
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