v0_1_0/src/rtmath.h

/***************************************************************************
 *                                                                         *
 *   LinuxSampler - modular, streaming capable sampler                     *
 *                                                                         *
 *   Copyright (C) 2003 by Benno Senoner and Christian Schoenebeck         *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   This program 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 General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, write to the Free Software           *
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston,                 *
 *   MA  02111-1307  USA                                                   *
 ***************************************************************************/

#ifndef __RT_MATH_H__
#define __RT_MATH_H__

#include <math.h>
#include "global.h"

/// Needed for calculating frequency ratio used to pitch a sample
#define TWELVEHUNDREDTH_ROOT_OF_TWO     1.000577789506555

/** Real Time Math
 *
 * Math functions for real time operation.
 */
class RTMath {
    public:
        /**
         * Converts a double to integer type.
         */
        inline static int DoubleToInt(double f) {
            #if ARCH_X86
            int i;
            __asm__ ("fistl %0" : "=m"(i) : "st"(f - 0.5) );
            return i;
            #else
            return (int) f;
            #endif // ARCH_X86
        }

        /**
         * Calculates the frequency ratio for a pitch value given in cents
         * (assuming equal tempered scale of course, divided into 12
         * semitones per octave and 100 cents per semitone).
         *
         * Note: MAX_PITCH (defined in global.h) has to be defined to an
         * appropriate value, otherwise the behavior of this function is
         * undefined, but most probably if MAX_PITCH is too small, the
         * application will crash due to segmentation fault here.
         *
         * @param cents - pitch value in cents (+1200 cents means +1 octave)
         * @returns  frequency ratio (e.g. +2.0 for +1 octave)
         */
        inline static double CentsToFreqRatio(double Cents) {
            int   index_int   = DoubleToInt(Cents); // integer index
            float index_fract = Cents - index_int;  // fractional part of index
            return pCentsToFreqTable[index_int] + index_fract * (pCentsToFreqTable[index_int+1] - pCentsToFreqTable[index_int]);
        }

    private:
        static float  CentsToFreqTable[MAX_PITCH * 1200 * 2 + 1];
        static float* pCentsToFreqTable;

        static float* InitCentsToFreqTable();
};

#endif // __RT_MATH_H__
1	/***************************************************************************
2	* *
3	* LinuxSampler - modular, streaming capable sampler *
4	* *
5	* Copyright (C) 2003 by Benno Senoner and Christian Schoenebeck *
6	* *
7	* This program is free software; you can redistribute it and/or modify *
8	* it under the terms of the GNU General Public License as published by *
9	* the Free Software Foundation; either version 2 of the License, or *
10	* (at your option) any later version. *
11	* *
12	* This program is distributed in the hope that it will be useful, *
13	* but WITHOUT ANY WARRANTY; without even the implied warranty of *
14	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
15	* GNU General Public License for more details. *
16	* *
17	* You should have received a copy of the GNU General Public License *
18	* along with this program; if not, write to the Free Software *
19	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, *
20	* MA 02111-1307 USA *
21	***************************************************************************/
22
23	#ifndef __RT_MATH_H__
24	#define __RT_MATH_H__
25
26	#include <math.h>
27	#include "global.h"
28
29	/// Needed for calculating frequency ratio used to pitch a sample
30	#define TWELVEHUNDREDTH_ROOT_OF_TWO 1.000577789506555
31
32	/** Real Time Math
33	*
34	* Math functions for real time operation.
35	*/
36	class RTMath {
37	public:
38	/**
39	* Converts a double to integer type.
40	*/
41	inline static int DoubleToInt(double f) {
42	#if ARCH_X86
43	int i;
44	__asm__ ("fistl %0" : "=m"(i) : "st"(f - 0.5) );
45	return i;
46	#else
47	return (int) f;
48	#endif // ARCH_X86
49	}
50
51	/**
52	* Calculates the frequency ratio for a pitch value given in cents
53	* (assuming equal tempered scale of course, divided into 12
54	* semitones per octave and 100 cents per semitone).
55	*
56	* Note: MAX_PITCH (defined in global.h) has to be defined to an
57	* appropriate value, otherwise the behavior of this function is
58	* undefined, but most probably if MAX_PITCH is too small, the
59	* application will crash due to segmentation fault here.
60	*
61	* @param cents - pitch value in cents (+1200 cents means +1 octave)
62	* @returns frequency ratio (e.g. +2.0 for +1 octave)
63	*/
64	inline static double CentsToFreqRatio(double Cents) {
65	int index_int = DoubleToInt(Cents); // integer index
66	float index_fract = Cents - index_int; // fractional part of index
67	return pCentsToFreqTable[index_int] + index_fract * (pCentsToFreqTable[index_int+1] - pCentsToFreqTable[index_int]);
68	}
69
70	private:
71	static float CentsToFreqTable[MAX_PITCH * 1200 * 2 + 1];
72	static float* pCentsToFreqTable;
73
74	static float* InitCentsToFreqTable();
75	};
76
77	#endif // __RT_MATH_H__