/* sound.c -- generally handy routines for sound. */

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include "sound.h"


double rnd( void ) {
  return( (double) random() / RAND_MAX );
}


int random_lt( int n ) {
  int bits, val;

  // Taken from Sun's published source for java.util.Random::nextInt().
  if (n<=0) {
    fprintf( stderr, "random_lt: n == %d <= 0\n", n );
  }
  
  if ((n & -n) == n) {  // i.e., n is a power of 2
    return( (int)((n * (long) random() ) >> 31) );
}
  
  do {
    bits = random();
    val = bits % n;
  } while(bits - val + (n-1) < 0);
  return val;
}



/* Freq. of a chromatic note where A440 = 0. */
double chrom_freq( double chrom ) {
  return( ( 440 * CYCLE / SECOND ) * exp2( chrom / 12 ) );
}

// Freq. of a standard midi note;
double midi_note_freq( double midi_note ) { // Allows fractional midi notes.
  return( chrom_freq( midi_note - MIDI_A440 ) );
}



/* This format is 12 characters wide: ###:##.##### */
void fprint_time( FILE *stream, long t ) { /* positive times only */
  int minutes = t / MINUTE;
  double seconds = ( (double) t - ( minutes * MINUTE ) ) / SECOND;

  fprintf( stream, "%3d:%08.5f", minutes, seconds );
}


/* This format is 13 characters wide: ###:##.##+### */
void fprint_time_step( FILE *stream, long t ) { /* positive times only */
  int minutes = t / MINUTE;

  t = t % MINUTE;
  fprintf( stream, "%3d:%05.2f+%03d", minutes, (t / 441) * .01, t % 441 );
}


// Format is [+-][mmm:][SS][.[hh][{+-}sss]]
long parse_time( char *str, int *p_is_relative, char **endptr ) {
  char *puncs [4] = { "+-", ":", ".", "+-" };
  double nums[4];
  long t;
  int i;
  char *p, *ps[ 4 ];

  for( i = 0;  i < 4;  i++ ) {
    nums[i] = 0;
    ps[i] = NULL;
    for( p = puncs[i];  *p != '\0';  p++ ) {
      if( *str == *p ) {
	ps[i] = p;
	str++;
	break; // Only one of each.
      }
    }
    if( isspace( *str )  ||  ispunct( *str ) )  {
      continue; // Don't let strtol accept space or +/-.
    }
    nums[i] = strtol( str, &p, 10 );
    // Special for fractions of seconds:
    if( i == 2 ) {
      while( str < p ) {
	str++;
	nums[2] = nums[2] / 10;
      }
    }
    str = p;
  }
  // If no ':', first number is seconds, not minutes:
  if( ps[1] == NULL ) {
    nums[1] = nums[0];
    nums[0] = 0;
  }
  // Final '-' makes negative sample offset:
  if( ps[3] != NULL  &&  *ps[3] == '-' ) {
    nums[3] = -nums[3];
  }
  t = nums[0] * MINUTE + nums[1] * SECOND
    + nums[2] * SECOND + nums[3];
  if( *p_is_relative = ( ps[0] != NULL ) ) {
    if( *ps[0] == '-' ) {
      t = -t;
    }
  }
  if( endptr != NULL )  *endptr = str;
  return( t );
}