%%	options

copyright owner	=	Dirk Krause
copyright year	=	2014
license		=	bsd



%%	header

/**	@file	dk3maus.h	Mathematical operations on unsigned short.
*/

#include <dk3conf.h>

#include <stdio.h>
#if DK3_HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#if DK3_HAVE_STDINT
#include <stdint.h>
#endif
#if DK3_HAVE_INTTYPES_H
#include <inttypes.h>
#endif
#if DK3_HAVE_LIMITS_H
#include <limits.h>
#endif
#if DK3_HAVE_MATH_H
#include <math.h>
#endif
#if DK3_HAVE_FLOAT_H
#include <float.h>
#endif


#ifdef __cplusplus
extern "C" {
#endif

/**	Addition.
	@param	a	Left operand.
	@param	b	Right operand.
	@param	ec	Pointer to error code variable, may be NULL.
	The variable may be set to DK3_ERROR_MATH_OVERFLOW when returning.
	@return	Summary of a and b.
*/
unsigned short
dk3ma_us_add_ok(unsigned short a, unsigned short b, int *ec);

/**	Substraction.
	@param	a	Left operand.
	@param	b	Right operand.
	@param	ec	Pointer to error code variable, may be NULL.
	The variable may be set to DK3_ERROR_MATH_OVERFLOW when returning.
	@return	Difference of a and b.
*/
unsigned short
dk3ma_us_sub_ok(unsigned short a, unsigned short b, int *ec);

/**	Multiplication.
	@param	a	Left operand.
	@param	b	Right operand.
	@param	ec	Pointer to error code variable, may be NULL.
	The variable may be set to DK3_ERROR_MATH_OVERFLOW when returning.
	@return	Product of a and b.
*/
unsigned short
dk3ma_us_mul_ok(unsigned short a, unsigned short b, int *ec);

/**	Division.
	@param	a	Left operand (nominator).
	@param	b	Right operand (denominator).
	@param	ec	Pointer to error code variable, may be NULL.
	The variable may be set to DK3_ERROR_MATH_OVERFLOW or
	DK3_ERROR_MATH_DIVZERO when returning.
	@return	Fraction of a and b.
*/
unsigned short
dk3ma_us_div_ok(unsigned short a, unsigned short b, int *ec);

/**	Greatest common divisor.
	@param	a	Left operand.
	@param	b	Right operand.
	The variable may be set to DK3_ERROR_MATH_OVERFLOW when returning.
	@return	Greatest common divisor of a and b.
*/
unsigned short
dk3ma_us_gcd(unsigned short a, unsigned short b);

#ifdef __cplusplus
}
#endif



%%	module



#include "dk3ma.h"



$!trace-include



unsigned short
dk3ma_us_add_ok(unsigned short a, unsigned short b, int *ec)
{
  if (NULL != ec) {
    if ((DK3_US_MAX - a) < b) { *ec = DK3_ERROR_MATH_OVERFLOW; }
  }
  return (a + b);
}



unsigned short
dk3ma_us_sub_ok(unsigned short a, unsigned short b, int *ec)
{
  if (NULL != ec) { if (b > a) { *ec = DK3_ERROR_MATH_OVERFLOW; } }
  return (a - b);
}



unsigned short
dk3ma_us_mul_ok(unsigned short a, unsigned short b, int *ec)
{
  if (NULL != ec) {
    if (0 != a) {
      if ((DK3_US_MAX / a) < b) { *ec = DK3_ERROR_MATH_OVERFLOW; }
    }
  }
  return (a * b);
}



unsigned short
dk3ma_us_div_ok(unsigned short a, unsigned short b, int *ec)
{
  unsigned short	back	=	(unsigned short)0;
  if (0 != b) {
    back = a / b;
  } else {
    if (NULL != ec) { *ec = DK3_ERROR_MATH_DIVZERO; }
    back = DK3_US_MAX;
  }
  return back;
}



unsigned short
dk3ma_us_gcd(unsigned short a, unsigned short b)
{
  unsigned short	h;
  while (0 < b) {
    h = a % b;
    a = b;
    b = h;
  }
  if (0 == a) { a = (unsigned short)1; }
  return a;
}