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/*
* Schism Tracker - a cross-platform Impulse Tracker clone
* copyright (c) 2003-2005 Storlek <storlek@rigelseven.com>
* copyright (c) 2005-2008 Mrs. Brisby <mrs.brisby@nimh.org>
* copyright (c) 2009 Storlek & Mrs. Brisby
* copyright (c) 2010-2012 Storlek
* URL: http://schismtracker.org/
*
* 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 SCHISM_UTIL_H_
#define SCHISM_UTIL_H_
#include "headers.h"
/*Conversion*/
/* linear -> deciBell*/
/* amplitude normalized to 1.0f.*/
SCHISM_CONST static inline SCHISM_ALWAYS_INLINE float dB(float amplitude)
{
return 20.0f * log10(amplitude);
}
/// deciBell -> linear*/
SCHISM_CONST static inline SCHISM_ALWAYS_INLINE float dB2_amp(float db)
{
return pow(10.0f, db / 20.0f);
}
/* linear -> deciBell*/
/* power normalized to 1.0f.*/
SCHISM_CONST static inline SCHISM_ALWAYS_INLINE float pdB(float power)
{
return 10.0f * log10(power);
}
/* deciBell -> linear*/
SCHISM_CONST static inline SCHISM_ALWAYS_INLINE float dB2_power(float db)
{
return pow(10.0f, db / 10.0f);
}
/* linear -> deciBell*/
/* amplitude normalized to 1.0f.*/
/* Output scaled (and clipped) to 128 lines with noisefloor range.*/
/* ([0..128] = [-noisefloor..0dB])*/
/* correction_dBs corrects the dB after converted, but before scaling.*/
SCHISM_CONST static inline SCHISM_ALWAYS_INLINE short dB_s(int noisefloor, float amplitude, float correction_dBs)
{
const float db = dB(amplitude) + correction_dBs;
const int x = (int)(128.0f * (db + noisefloor)) / noisefloor;
return CLAMP(x, 0, 127);
}
/* deciBell -> linear*/
/* Input scaled to 128 lines with noisefloor range.*/
/* ([0..128] = [-noisefloor..0dB])*/
/* amplitude normalized to 1.0f.*/
/* correction_dBs corrects the dB after converted, but before scaling.*/
SCHISM_CONST static inline SCHISM_ALWAYS_INLINE short dB2_amp_s(int noisefloor, int db, float correction_dBs)
{
return dB2_amp((db * noisefloor / 128.0f) - noisefloor - correction_dBs);
}
/* linear -> deciBell*/
/* power normalized to 1.0f.*/
/* Output scaled (and clipped) to 128 lines with noisefloor range.*/
/* ([0..128] = [-noisefloor..0dB])*/
/* correction_dBs corrects the dB after converted, but before scaling.*/
SCHISM_CONST static inline SCHISM_ALWAYS_INLINE short pdB_s(int noisefloor, float power, float correction_dBs)
{
const float db = pdB(power) + correction_dBs;
const int x = (int)(128.0f * (db + noisefloor)) / noisefloor;
return CLAMP(x, 0, 127);
}
/* deciBell -> linear*/
/* Input scaled to 128 lines with noisefloor range.*/
/* ([0..128] = [-noisefloor..0dB])*/
/* power normalized to 1.0f.*/
/* correction_dBs corrects the dB after converted, but before scaling.*/
SCHISM_CONST static inline SCHISM_ALWAYS_INLINE short dB2_power_s(int noisefloor, int db, float correction_dBs)
{
return dB2_power((db * noisefloor / 128.0f) - noisefloor - correction_dBs);
}
/* integer sqrt (very fast; 32 bits limited) */
SCHISM_CONST static inline SCHISM_ALWAYS_INLINE uint32_t i_sqrt(uint32_t r)
{
uint32_t t, b, c = 0;
for (b = 0x10000000; b != 0; b >>= 2) {
t = c + b;
c >>= 1;
if (t <= r) {
r -= t;
c += b;
}
}
return c;
}
FILE *mkfstemp(char *template);
#endif /* SCHISM_UTIL_H_ */
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