/** @file patest_pink.c	@ingroup test_src	@brief Generate Pink Noise using Gardner method.	Optimization suggested by James McCartney uses a tree	to select which random value to replace.<pre>	x x x x x x x x x x x x x x x x 	x   x   x   x   x   x   x   x   	x       x       x       x       	 x               x               	   x   </pre>                            	Tree is generated by counting trailing zeros in an increasing index.	When the index is zero, no random number is selected.	@author Phil Burk  http://www.softsynth.com*//* * $Id: patest_pink.c 1097 2006-08-26 08:27:53Z rossb $ * * This program uses the PortAudio Portable Audio Library. * For more information see: http://www.portaudio.com * Copyright (c) 1999-2000 Ross Bencina and Phil Burk * * Permission is hereby granted, free of charge, to any person obtaining * a copy of this software and associated documentation files * (the "Software"), to deal in the Software without restriction, * including without limitation the rights to use, copy, modify, merge, * publish, distribute, sublicense, and/or sell copies of the Software, * and to permit persons to whom the Software is furnished to do so, * subject to the following conditions: * * The above copyright notice and this permission notice shall be * included in all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. *//* * The text above constitutes the entire PortAudio license; however,  * the PortAudio community also makes the following non-binding requests: * * Any person wishing to distribute modifications to the Software is * requested to send the modifications to the original developer so that * they can be incorporated into the canonical version. It is also  * requested that these non-binding requests be included along with the  * license above. */#include <stdio.h>#include <math.h>#include "portaudio.h"#define PINK_MAX_RANDOM_ROWS   (30)#define PINK_RANDOM_BITS       (24)#define PINK_RANDOM_SHIFT      ((sizeof(long)*8)-PINK_RANDOM_BITS)typedef struct{    long      pink_Rows[PINK_MAX_RANDOM_ROWS];    long      pink_RunningSum;   /* Used to optimize summing of generators. */    int       pink_Index;        /* Incremented each sample. */    int       pink_IndexMask;    /* Index wrapped by ANDing with this mask. */    float     pink_Scalar;       /* Used to scale within range of -1.0 to +1.0 */}PinkNoise;/* Prototypes */static unsigned long GenerateRandomNumber( void );void InitializePinkNoise( PinkNoise *pink, int numRows );float GeneratePinkNoise( PinkNoise *pink );/************************************************************//* Calculate pseudo-random 32 bit number based on linear congruential method. */static unsigned long GenerateRandomNumber( void ){    /* Change this seed for different random sequences. */    static unsigned long randSeed = 22222;    randSeed = (randSeed * 196314165) + 907633515;    return randSeed;}/************************************************************//* Setup PinkNoise structure for N rows of generators. */void InitializePinkNoise( PinkNoise *pink, int numRows ){    int i;    long pmax;    pink->pink_Index = 0;    pink->pink_IndexMask = (1<<numRows) - 1;    /* Calculate maximum possible signed random value. Extra 1 for white noise always added. */    pmax = (numRows + 1) * (1<<(PINK_RANDOM_BITS-1));    pink->pink_Scalar = 1.0f / pmax;    /* Initialize rows. */    for( i=0; i<numRows; i++ ) pink->pink_Rows[i] = 0;    pink->pink_RunningSum = 0;}#define PINK_MEASURE#ifdef PINK_MEASUREfloat pinkMax = -999.0;float pinkMin =  999.0;#endif/* Generate Pink noise values between -1.0 and +1.0 */float GeneratePinkNoise( PinkNoise *pink ){    long newRandom;    long sum;    float output;    /* Increment and mask index. */    pink->pink_Index = (pink->pink_Index + 1) & pink->pink_IndexMask;    /* If index is zero, don't update any random values. */    if( pink->pink_Index != 0 )    {        /* Determine how many trailing zeros in PinkIndex. */        /* This algorithm will hang if n==0 so test first. */        int numZeros = 0;        int n = pink->pink_Index;        while( (n & 1) == 0 )        {            n = n >> 1;            numZeros++;        }        /* Replace the indexed ROWS random value.         * Subtract and add back to RunningSum instead of adding all the random         * values together. Only one changes each time.         */        pink->pink_RunningSum -= pink->pink_Rows[numZeros];        newRandom = ((long)GenerateRandomNumber()) >> PINK_RANDOM_SHIFT;        pink->pink_RunningSum += newRandom;        pink->pink_Rows[numZeros] = newRandom;    }    /* Add extra white noise value. */    newRandom = ((long)GenerateRandomNumber()) >> PINK_RANDOM_SHIFT;    sum = pink->pink_RunningSum + newRandom;    /* Scale to range of -1.0 to 0.9999. */    output = pink->pink_Scalar * sum;#ifdef PINK_MEASURE    /* Check Min/Max */    if( output > pinkMax ) pinkMax = output;    else if( output < pinkMin ) pinkMin = output;#endif    return output;}/*******************************************************************/#define PINK_TEST#ifdef PINK_TEST/* Context for callback routine. */typedef struct{    PinkNoise   leftPink;    PinkNoise   rightPink;    unsigned int sampsToGo;}paTestData;/* This routine will be called by the PortAudio engine when audio is needed.** It may called at interrupt level on some machines so don't do anything** that could mess up the system like calling malloc() or free().*/static int patestCallback(const void*                     inputBuffer,                          void*                           outputBuffer,                          unsigned long                   framesPerBuffer,			              const PaStreamCallbackTimeInfo* timeInfo,			              PaStreamCallbackFlags           statusFlags,                          void*                           userData){    int finished;    int i;    int numFrames;    paTestData *data = (paTestData*)userData;    float *out = (float*)outputBuffer;    (void) inputBuffer; /* Prevent "unused variable" warnings. */    /* Are we almost at end. */    if( data->sampsToGo < framesPerBuffer )    {        numFrames = data->sampsToGo;        finished = 1;    }    else    {        numFrames = framesPerBuffer;        finished = 0;    }    for( i=0; i<numFrames; i++ )    {        *out++ = GeneratePinkNoise( &data->leftPink );        *out++ = GeneratePinkNoise( &data->rightPink );    }    data->sampsToGo -= numFrames;    return finished;}/*******************************************************************/int main(void);int main(void){    PaStream*           stream;    PaError             err;    paTestData          data;    PaStreamParameters  outputParameters;    int                 totalSamps;    static const double SR  = 44100.0;    static const int    FPB = 2048; /* Frames per buffer: 46 ms buffers. */        /* Initialize two pink noise signals with different numbers of rows. */    InitializePinkNoise( &data.leftPink,  12 );    InitializePinkNoise( &data.rightPink, 16 );    /* Look at a few values. */    {        int i;        float pink;        for( i=0; i<20; i++ )        {            pink = GeneratePinkNoise( &data.leftPink );            printf("Pink = %f\n", pink );        }    }    data.sampsToGo = totalSamps = (int)(60.0 * SR);   /* Play a whole minute. */    err = Pa_Initialize();    if( err != paNoError ) goto error;    /* Open a stereo PortAudio stream so we can hear the result. */    outputParameters.device = Pa_GetDefaultOutputDevice(); /* Take the default output device. */    outputParameters.channelCount = 2;                     /* Stereo output, most likely supported. */    outputParameters.hostApiSpecificStreamInfo = NULL;    outputParameters.sampleFormat = paFloat32;             /* 32 bit floating point output. */    outputParameters.suggestedLatency =                     Pa_GetDeviceInfo(outputParameters.device)->defaultLowOutputLatency;    err = Pa_OpenStream(&stream,                        NULL,                              /* No input. */                        &outputParameters,                        SR,                                /* Sample rate. */                        FPB,                               /* Frames per buffer. */                        paClipOff, /* we won't output out of range samples so don't bother clipping them */                        patestCallback,                        &data);    if( err != paNoError ) goto error;    err = Pa_StartStream( stream );    if( err != paNoError ) goto error;    printf("Stereo pink noise for one minute...\n");    while( ( err = Pa_IsStreamActive( stream ) ) == 1 ) Pa_Sleep(100);    if( err < 0 ) goto error;    err = Pa_CloseStream( stream );    if( err != paNoError ) goto error;#ifdef PINK_MEASURE    printf("Pink min = %f, max = %f\n", pinkMin, pinkMax );#endif    Pa_Terminate();    return 0;error:    Pa_Terminate();    fprintf( stderr, "An error occured while using the portaudio stream\n" );    fprintf( stderr, "Error number: %d\n", err );    fprintf( stderr, "Error message: %s\n", Pa_GetErrorText( err ) );    return 0;}#endif /* PINK_TEST */