numUtil.c

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#include "log.h"
#include "format.h"
#include "numUtil.h"


int roundingScale(int a, int p, int q)
{
  if (a > 100000 || p > 100000)
    {
      double x = a;
      x *= p;
      x /= q;
      return round(x);
    }
  else
    return (a*p + q/2)/q;
}



int  rangeIntersection(int start1, int end1, int start2, int end2)
{
  int s = MAX(start1,start2);
  int e = MIN(end1,end2);
  return e-s;
}



int positiveRangeIntersection(int start1, int end1, int start2, int end2)

{
  int ret = rangeIntersection(start1,end1,start2,end2);
  if (ret < 0)
    ret = 0;
  return ret;
}



unsigned byteSwap32(unsigned a)
{
  union {unsigned whole; unsigned char bytes[4];} u,v;
  u.whole = a;
  v.bytes[0] = u.bytes[3];
  v.bytes[1] = u.bytes[2];
  v.bytes[2] = u.bytes[1];
  v.bytes[3] = u.bytes[0];
  return v.whole;
}



int digitsBaseTwo(unsigned long x)
{
  int digits = 0;
  while (x)
    {
      digits += 1;
      x >>= 1;
    }
  return digits;
}



int digitsBaseTen(int x)
{
  int digCount = 1;
  if (x < 0)
    {
      digCount = 2;
      x = -x;
    }
  while (x >= 10)
    {
      digCount += 1;
      x /= 10;
    }
  return digCount;
}

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