michael@0: ////////////////////////////////////////////////////////////////////////////////
michael@0: /// 
michael@0: /// Linear interpolation algorithm.
michael@0: ///
michael@0: /// Author        : Copyright (c) Olli Parviainen
michael@0: /// Author e-mail : oparviai 'at' iki.fi
michael@0: /// SoundTouch WWW: http://www.surina.net/soundtouch
michael@0: ///
michael@0: ////////////////////////////////////////////////////////////////////////////////
michael@0: //
michael@0: // $Id: InterpolateLinear.cpp 180 2014-01-06 19:16:02Z oparviai $
michael@0: //
michael@0: ////////////////////////////////////////////////////////////////////////////////
michael@0: //
michael@0: // License :
michael@0: //
michael@0: //  SoundTouch audio processing library
michael@0: //  Copyright (c) Olli Parviainen
michael@0: //
michael@0: //  This library is free software; you can redistribute it and/or
michael@0: //  modify it under the terms of the GNU Lesser General Public
michael@0: //  License as published by the Free Software Foundation; either
michael@0: //  version 2.1 of the License, or (at your option) any later version.
michael@0: //
michael@0: //  This library is distributed in the hope that it will be useful,
michael@0: //  but WITHOUT ANY WARRANTY; without even the implied warranty of
michael@0: //  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
michael@0: //  Lesser General Public License for more details.
michael@0: //
michael@0: //  You should have received a copy of the GNU Lesser General Public
michael@0: //  License along with this library; if not, write to the Free Software
michael@0: //  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
michael@0: //
michael@0: ////////////////////////////////////////////////////////////////////////////////
michael@0: 
michael@0: #include <assert.h>
michael@0: #include <stdlib.h>
michael@0: #include "InterpolateLinear.h"
michael@0: 
michael@0: using namespace soundtouch;
michael@0: 
michael@0: //////////////////////////////////////////////////////////////////////////////
michael@0: //
michael@0: // InterpolateLinearInteger - integer arithmetic implementation
michael@0: // 
michael@0: 
michael@0: /// fixed-point interpolation routine precision
michael@0: #define SCALE    65536
michael@0: 
michael@0: 
michael@0: // Constructor
michael@0: InterpolateLinearInteger::InterpolateLinearInteger() : TransposerBase()
michael@0: {
michael@0:     // Notice: use local function calling syntax for sake of clarity, 
michael@0:     // to indicate the fact that C++ constructor can't call virtual functions.
michael@0:     resetRegisters();
michael@0:     setRate(1.0f);
michael@0: }
michael@0: 
michael@0: 
michael@0: void InterpolateLinearInteger::resetRegisters()
michael@0: {
michael@0:     iFract = 0;
michael@0: }
michael@0: 
michael@0: 
michael@0: // Transposes the sample rate of the given samples using linear interpolation. 
michael@0: // 'Mono' version of the routine. Returns the number of samples returned in 
michael@0: // the "dest" buffer
michael@0: int InterpolateLinearInteger::transposeMono(SAMPLETYPE *dest, const SAMPLETYPE *src, int &srcSamples)
michael@0: {
michael@0:     int i;
michael@0:     int srcSampleEnd = srcSamples - 1;
michael@0:     int srcCount = 0;
michael@0: 
michael@0:     i = 0;
michael@0:     while (srcCount < srcSampleEnd)
michael@0:     {
michael@0:         LONG_SAMPLETYPE temp;
michael@0:     
michael@0:         assert(iFract < SCALE);
michael@0: 
michael@0:         temp = (SCALE - iFract) * src[0] + iFract * src[1];
michael@0:         dest[i] = (SAMPLETYPE)(temp / SCALE);
michael@0:         i++;
michael@0: 
michael@0:         iFract += iRate;
michael@0: 
michael@0:         int iWhole = iFract / SCALE;
michael@0:         iFract -= iWhole * SCALE;
michael@0:         srcCount += iWhole;
michael@0:         src += iWhole;
michael@0:     }
michael@0:     srcSamples = srcCount;
michael@0: 
michael@0:     return i;
michael@0: }
michael@0: 
michael@0: 
michael@0: // Transposes the sample rate of the given samples using linear interpolation. 
michael@0: // 'Stereo' version of the routine. Returns the number of samples returned in 
michael@0: // the "dest" buffer
michael@0: int InterpolateLinearInteger::transposeStereo(SAMPLETYPE *dest, const SAMPLETYPE *src, int &srcSamples)
michael@0: {
michael@0:     int i;
michael@0:     int srcSampleEnd = srcSamples - 1;
michael@0:     int srcCount = 0;
michael@0: 
michael@0:     i = 0;
michael@0:     while (srcCount < srcSampleEnd)
michael@0:     {
michael@0:         LONG_SAMPLETYPE temp0;
michael@0:         LONG_SAMPLETYPE temp1;
michael@0:     
michael@0:         assert(iFract < SCALE);
michael@0: 
michael@0:         temp0 = (SCALE - iFract) * src[0] + iFract * src[2];
michael@0:         temp1 = (SCALE - iFract) * src[1] + iFract * src[3];
michael@0:         dest[0] = (SAMPLETYPE)(temp0 / SCALE);
michael@0:         dest[1] = (SAMPLETYPE)(temp1 / SCALE);
michael@0:         dest += 2;
michael@0:         i++;
michael@0: 
michael@0:         iFract += iRate;
michael@0: 
michael@0:         int iWhole = iFract / SCALE;
michael@0:         iFract -= iWhole * SCALE;
michael@0:         srcCount += iWhole;
michael@0:         src += 2*iWhole;
michael@0:     }
michael@0:     srcSamples = srcCount;
michael@0: 
michael@0:     return i;
michael@0: }
michael@0: 
michael@0: 
michael@0: int InterpolateLinearInteger::transposeMulti(SAMPLETYPE *dest, const SAMPLETYPE *src, int &srcSamples)
michael@0: {
michael@0:     int i;
michael@0:     int srcSampleEnd = srcSamples - 1;
michael@0:     int srcCount = 0;
michael@0: 
michael@0:     i = 0;
michael@0:     while (srcCount < srcSampleEnd)
michael@0:     {
michael@0:         LONG_SAMPLETYPE temp, vol1;
michael@0:     
michael@0:         assert(iFract < SCALE);
michael@0:         vol1 = (SCALE - iFract);
michael@0:         for (int c = 0; c < numChannels; c ++)
michael@0:         {
michael@0:             temp = vol1 * src[c] + iFract * src[c + numChannels];
michael@0:             dest[0] = (SAMPLETYPE)(temp / SCALE);
michael@0:             dest ++;
michael@0:         }
michael@0:         i++;
michael@0: 
michael@0:         iFract += iRate;
michael@0: 
michael@0:         int iWhole = iFract / SCALE;
michael@0:         iFract -= iWhole * SCALE;
michael@0:         srcCount += iWhole;
michael@0:         src += iWhole * numChannels;
michael@0:     }
michael@0:     srcSamples = srcCount;
michael@0: 
michael@0:     return i;
michael@0: }
michael@0: 
michael@0: 
michael@0: // Sets new target iRate. Normal iRate = 1.0, smaller values represent slower 
michael@0: // iRate, larger faster iRates.
michael@0: void InterpolateLinearInteger::setRate(float newRate)
michael@0: {
michael@0:     iRate = (int)(newRate * SCALE + 0.5f);
michael@0:     TransposerBase::setRate(newRate);
michael@0: }
michael@0: 
michael@0: 
michael@0: //////////////////////////////////////////////////////////////////////////////
michael@0: //
michael@0: // InterpolateLinearFloat - floating point arithmetic implementation
michael@0: // 
michael@0: //////////////////////////////////////////////////////////////////////////////
michael@0: 
michael@0: 
michael@0: // Constructor
michael@0: InterpolateLinearFloat::InterpolateLinearFloat() : TransposerBase()
michael@0: {
michael@0:     // Notice: use local function calling syntax for sake of clarity, 
michael@0:     // to indicate the fact that C++ constructor can't call virtual functions.
michael@0:     resetRegisters();
michael@0:     setRate(1.0f);
michael@0: }
michael@0: 
michael@0: 
michael@0: void InterpolateLinearFloat::resetRegisters()
michael@0: {
michael@0:     fract = 0;
michael@0: }
michael@0: 
michael@0: 
michael@0: // Transposes the sample rate of the given samples using linear interpolation. 
michael@0: // 'Mono' version of the routine. Returns the number of samples returned in 
michael@0: // the "dest" buffer
michael@0: int InterpolateLinearFloat::transposeMono(SAMPLETYPE *dest, const SAMPLETYPE *src, int &srcSamples)
michael@0: {
michael@0:     int i;
michael@0:     int srcSampleEnd = srcSamples - 1;
michael@0:     int srcCount = 0;
michael@0: 
michael@0:     i = 0;
michael@0:     while (srcCount < srcSampleEnd)
michael@0:     {
michael@0:         double out;
michael@0:         assert(fract < 1.0);
michael@0: 
michael@0:         out = (1.0 - fract) * src[0] + fract * src[1];
michael@0:         dest[i] = (SAMPLETYPE)out;
michael@0:         i ++;
michael@0: 
michael@0:         // update position fraction
michael@0:         fract += rate;
michael@0:         // update whole positions
michael@0:         int whole = (int)fract;
michael@0:         fract -= whole;
michael@0:         src += whole;
michael@0:         srcCount += whole;
michael@0:     }
michael@0:     srcSamples = srcCount;
michael@0:     return i;
michael@0: }
michael@0: 
michael@0: 
michael@0: // Transposes the sample rate of the given samples using linear interpolation. 
michael@0: // 'Mono' version of the routine. Returns the number of samples returned in 
michael@0: // the "dest" buffer
michael@0: int InterpolateLinearFloat::transposeStereo(SAMPLETYPE *dest, const SAMPLETYPE *src, int &srcSamples)
michael@0: {
michael@0:     int i;
michael@0:     int srcSampleEnd = srcSamples - 1;
michael@0:     int srcCount = 0;
michael@0: 
michael@0:     i = 0;
michael@0:     while (srcCount < srcSampleEnd)
michael@0:     {
michael@0:         double out0, out1;
michael@0:         assert(fract < 1.0);
michael@0: 
michael@0:         out0 = (1.0 - fract) * src[0] + fract * src[2];
michael@0:         out1 = (1.0 - fract) * src[1] + fract * src[3];
michael@0:         dest[2*i]   = (SAMPLETYPE)out0;
michael@0:         dest[2*i+1] = (SAMPLETYPE)out1;
michael@0:         i ++;
michael@0: 
michael@0:         // update position fraction
michael@0:         fract += rate;
michael@0:         // update whole positions
michael@0:         int whole = (int)fract;
michael@0:         fract -= whole;
michael@0:         src += 2*whole;
michael@0:         srcCount += whole;
michael@0:     }
michael@0:     srcSamples = srcCount;
michael@0:     return i;
michael@0: }
michael@0: 
michael@0: 
michael@0: int InterpolateLinearFloat::transposeMulti(SAMPLETYPE *dest, const SAMPLETYPE *src, int &srcSamples)
michael@0: {
michael@0:     int i;
michael@0:     int srcSampleEnd = srcSamples - 1;
michael@0:     int srcCount = 0;
michael@0: 
michael@0:     i = 0;
michael@0:     while (srcCount < srcSampleEnd)
michael@0:     {
michael@0:         float temp, vol1;
michael@0:     
michael@0:         vol1 = (1.0f- fract);
michael@0:         for (int c = 0; c < numChannels; c ++)
michael@0:         {
michael@0:             temp = vol1 * src[c] + fract * src[c + numChannels];
michael@0:             *dest = (SAMPLETYPE)temp;
michael@0:             dest ++;
michael@0:         }
michael@0:         i++;
michael@0: 
michael@0:         fract += rate;
michael@0: 
michael@0:         int iWhole = (int)fract;
michael@0:         fract -= iWhole;
michael@0:         srcCount += iWhole;
michael@0:         src += iWhole * numChannels;
michael@0:     }
michael@0:     srcSamples = srcCount;
michael@0: 
michael@0:     return i;
michael@0: }