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