cf_util.h File Reference

#include "globaldefs.h"

Go to the source code of this file.

Functions
int	ilog2 (int a)
int	igcd (int a, int b)
int FACTORY_PUBLIC	ipower (int b, int n)
	int ipower ( int b, int m ) More...
void	factoryError_intern (const char *s)

Variables
EXTERN_VAR void(*	factoryError )(const char *s)

Function Documentation

factoryError_intern()

void factoryError_intern

(

const char *

s

)

Definition at line 75 of file cf_util.cc.

{
  fputs(s,stderr);
  abort();
}

igcd()

int igcd	(	int	a,
		int	b
	)

Definition at line 56 of file cf_util.cc.

{
    if ( a < 0 ) a = -a;
    if ( b < 0 ) b = -b;
 
    int c;
 
    while ( b != 0 )
    {
        c = a % b;
        a = b;
        b = c;
    }
    return a;
}

ilog2()

int ilog2

(

int

a

)

Definition at line 42 of file cf_util.cc.

{
  const unsigned int b[] = {0x2, 0xC, 0xF0, 0xFF00, 0xFFFF0000};
  const unsigned int S[] = {1, 2, 4, 8, 16};
 
  unsigned int r = 0; // result of log2(v) will go here
  if (v & b[4]) { v >>= S[4]; r |= S[4]; }
  if (v & b[3]) { v >>= S[3]; r |= S[3]; }
  if (v & b[2]) { v >>= S[2]; r |= S[2]; }
  if (v & b[1]) { v >>= S[1]; r |= S[1]; }
  if (v & b[0]) { v >>= S[0]; r |= S[0]; }
  return (int)r;
}

ipower()

int FACTORY_PUBLIC ipower	(	int	b,
		int	m
	)

int ipower ( int b, int m )

ipower() - calculate b^m in standard integer arithmetic.

Note: Beware of overflows.

Definition at line 27 of file cf_util.cc.

{
    int prod = 1;
 
    while ( m != 0 )
    {
        if ( m % 2 != 0 )
            prod *= b;
        m /= 2;
        if ( m != 0 )
            b *= b;
    }
    return prod;
}

Variable Documentation

factoryError

EXTERN_VAR void(* factoryError) (const char *s)

(

const char *

s

)

Definition at line 14 of file cf_util.h.