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/* FluidSynth - A Software Synthesizer
*
* Copyright (C) 2003 Peter Hanappe and others.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public License
* as published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* This library 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the Free
* Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA
*/
#ifndef _FLUID_PHASE_H
#define _FLUID_PHASE_H
#if HAVE_CONFIG_H
#include "config.h"
#endif
/*
* phase
*/
#define FLUID_INTERP_BITS 8
#define FLUID_INTERP_BITS_MASK 0xff000000
#define FLUID_INTERP_BITS_SHIFT 24
#define FLUID_INTERP_MAX 256
#define FLUID_FRACT_MAX ((double)4294967296.0)
/* fluid_phase_t
* Purpose:
* Playing pointer for voice playback
*
* When a sample is played back at a different pitch, the playing pointer in the
* source sample will not advance exactly one sample per output sample.
* This playing pointer is implemented using fluid_phase_t.
* It is a 64 bit number. The higher 32 bits contain the 'index' (number of
* the current sample), the lower 32 bits the fractional part.
*/
typedef unsigned long long fluid_phase_t;
/* Purpose:
* Set a to b.
* a: fluid_phase_t
* b: fluid_phase_t
*/
#define fluid_phase_set(a,b) a=b;
#define fluid_phase_set_int(a, b) ((a) = ((unsigned long long)(b)) << 32)
/* Purpose:
* Sets the phase a to a phase increment given in b.
* For example, assume b is 0.9. After setting a to it, adding a to
* the playing pointer will advance it by 0.9 samples. */
#define fluid_phase_set_float(a, b) \
(a) = (((unsigned long long)(b)) << 32) \
| (uint32) (((double)(b) - (int)(b)) * (double)FLUID_FRACT_MAX)
/* create a fluid_phase_t from an index and a fraction value */
#define fluid_phase_from_index_fract(index, fract) \
((((unsigned long long)(index)) << 32) + (fract))
/* Purpose:
* Return the index and the fractional part, respectively. */
#define fluid_phase_index(_x) \
((unsigned int)((_x) >> 32))
#define fluid_phase_fract(_x) \
((uint32)((_x) & 0xFFFFFFFF))
/* Get the phase index with fractional rounding */
#define fluid_phase_index_round(_x) \
((unsigned int)(((_x) + 0x80000000) >> 32))
/* Purpose:
* Takes the fractional part of the argument phase and
* calculates the corresponding position in the interpolation table.
* The fractional position of the playing pointer is calculated with a quite high
* resolution (32 bits). It would be unpractical to keep a set of interpolation
* coefficients for each possible fractional part...
*/
#define fluid_phase_fract_to_tablerow(_x) \
((unsigned int)(fluid_phase_fract(_x) & FLUID_INTERP_BITS_MASK) >> FLUID_INTERP_BITS_SHIFT)
#define fluid_phase_double(_x) \
((double)(fluid_phase_index(_x)) + ((double)fluid_phase_fract(_x) / FLUID_FRACT_MAX))
/* Purpose:
* Advance a by a step of b (both are fluid_phase_t).
*/
#define fluid_phase_incr(a, b) a += b
/* Purpose:
* Subtract b from a (both are fluid_phase_t).
*/
#define fluid_phase_decr(a, b) a -= b
/* Purpose:
* Subtract b samples from a.
*/
#define fluid_phase_sub_int(a, b) ((a) -= (unsigned long long)(b) << 32)
/* Purpose:
* Creates the expression a.index++. */
#define fluid_phase_index_plusplus(a) (((a) += 0x100000000LL)
#endif /* _FLUID_PHASE_H */
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