/*----------------------------------------------------------------------------
    ChucK Concurrent, On-the-fly Audio Programming Language
      Compiler and Virtual Machine

    Copyright (c) 2004 Ge Wang and Perry R. Cook.  All rights reserved.
      http://chuck.cs.princeton.edu/
      http://soundlab.cs.princeton.edu/

    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
    U.S.A.
-----------------------------------------------------------------------------*/

//-----------------------------------------------------------------------------
// name: util_math.cpp
// desc: a mini-compatibility library for math functions
//
// author: Ge Wang (gewang@cs.princeton.edu)
//         Perry R. Cook (prc@cs.princeton.edu)
//         Philip Davidson (philipd@alumni.princeton.edu)
// date: Spring 2004
//-----------------------------------------------------------------------------
#include "util_math.h"
#include <math.h>
#include <random>




//-----------------------------------------------------------------------------
#ifndef __OLDSCHOOL_RANDOM__ // not using old school, pre-c++11 compatibility
//-----------------------------------------------------------------------------
// name: ck_random() and ck_srandom()
// desc: chuck wrappers for random number generators
// 1.5.0.1 (ge) using mt19937 (requires c++11)
//-----------------------------------------------------------------------------
// mersenne twister RNG, based on the Mersenne prime (2^19937-1)
static std::mt19937 g_ck_global_rng;
// ck_random() returns a signed int no greater than CK_RANDOM_MAX
// to maintain parity between 64-bit and 32-bit systems, CK_RANDOM_MAX is set
// to 0x7fffffff (or 2,147,483,647--the largest 32-bit signed number) rather
// than mt19937's actual max of 0xffffffff (or 4,294,967,295, 2^32-1); this
// is ensured using modulo; the slight skewing of the resulting RNG distribution
// is considered acceptable
t_CKINT ck_random() { return g_ck_global_rng() % CK_RANDOM_MAX; }
// seed the random number generator
void ck_srandom( unsigned s ) { g_ck_global_rng.seed(s); }
//-----------------------------------------------------------------------------
#else // using old school random (pre-c++11)
//-----------------------------------------------------------------------------
// name: ck_random() and ck_srandom()
// desc: chuck wrappers for random number generators | 1.4.2.0 (ge)
//-----------------------------------------------------------------------------
#ifndef __PLATFORM_WIN32__
  t_CKINT ck_random() { return random(); }
  void ck_srandom( unsigned s ) { srandom( s ); }
#else // __WINDOWS_DS__
  t_CKINT ck_random() { return rand(); }
  void ck_srandom( unsigned s ) { srand( s ); }
#endif
//-----------------------------------------------------------------------------
#endif // __OLDSCHOOL_RANDOM__




// windows / visual c++
#ifdef __PLATFORM_WIN32__
#ifdef __CK_MATH_DEFINE_ROUND_TRUNC__
//-----------------------------------------------------------------------------
// name: round()
// desc: ...
//-----------------------------------------------------------------------------
  double round(double a)
  {
      if (a >= 0) return (double)(t_CKINT)(a + .5);
      else return (double)(t_CKINT)(a - .5);
  }


  //-----------------------------------------------------------------------------
  // name: trunc()
  // desc: ...
  //-----------------------------------------------------------------------------
  double trunc(double a)
  {
      return (double)(long)a;
  }
#endif // __CK_MATH_DEFINE_ROUND_TRUNC
#endif // __PLATFORM_WIN32__




//-----------------------------------------------------------------------------
// name: ck_remainder()
// desc: ...
//-----------------------------------------------------------------------------
double ck_remainder( double a, double b )
{
#ifdef __PLATFORM_WIN32__
    t_CKINT div = a/b;
    return a - b*div;
#else
    return remainder( a, b );
#endif
}




// the following 6 functions are lifted from PD source
// specifically x_acoustics.c
// http://puredata.info/downloads
#define LOGTWO 0.69314718055994528623
#define LOGTEN 2.302585092994




//-----------------------------------------------------------------------------
// name: mtof()
// desc: midi to freq
//-----------------------------------------------------------------------------
double mtof( double f )
{
    if( f <= -1500 ) return (0);
    else if( f > 1499 ) return (mtof(1499));
    // else return (8.17579891564 * exp(.0577622650 * f));
    // TODO: optimize
    else return ( pow(2,(f-69)/12.0) * 440.0 );
}




//-----------------------------------------------------------------------------
// name: ftom()
// desc: freq to midi
//-----------------------------------------------------------------------------
double ftom( double f )
{   
    // return (f > 0 ? 17.3123405046 * log(.12231220585 * f) : -1500);
    // TODO: optimize
    return (f > 0 ? (log(f/440.0) / LOGTWO) * 12.0 + 69 : -1500);
}




//-----------------------------------------------------------------------------
// name: powtodb()
// desc: ...
//-----------------------------------------------------------------------------
double powtodb( double f )
{
    if( f <= 0 ) return (0);
    else
    {
        double val = 100 + 10./LOGTEN * log(f);
        return (val < 0 ? 0 : val);
    }
}




//-----------------------------------------------------------------------------
// name: rmstodb()
// desc: ...
//-----------------------------------------------------------------------------
double rmstodb( double f )
{
    if( f <= 0 ) return (0);
    else
    {
        double val = 100 + 20./LOGTEN * log(f);
        return (val < 0 ? 0 : val);
    }
}




//-----------------------------------------------------------------------------
// name: dbtopow()
// desc: ...
//-----------------------------------------------------------------------------
double dbtopow( double f )
{
    if( f <= 0 )
        return (0);
    else
    {
        if( f > 870 ) f = 870;
        return (exp((LOGTEN * 0.1) * (f-100.)));
    }
}




//-----------------------------------------------------------------------------
// name: dbtorms()
// desc: ...
//-----------------------------------------------------------------------------
double dbtorms( double f )
{
    if( f <= 0 )
        return (0);
    else
    {
        if( f > 485 ) f = 485;
        return (exp((LOGTEN * 0.05) * (f-100.)));
    }
}




//-----------------------------------------------------------------------------
// name: nextpow2()
// desc: ...
//-----------------------------------------------------------------------------
unsigned long nextpow2( unsigned long n )
{
    unsigned long nn = n;
    for( ; n &= n-1; nn = n );
    return nn * 2;
}




//-----------------------------------------------------------------------------
// name: ensurepow2()
// desc: ...
//-----------------------------------------------------------------------------
unsigned long ensurepow2( unsigned long n )
{
    return nextpow2( n-1 );
}