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//**************************************
//
//INCLUDE files for :Compute parity for
// any integral type
//**************************************
//
/* +++Date last modified: 05-Jul-1997 */
/*
** RND_DIV.C - Rounded integer division
**
** public domain - suggested by Dave Hansen in comp.lang.c
*/
#include
int round_div(int n, int d)
{
div_t res = div(n,d);
div_t rnd = div(res.rem, (abs(d)+1)/2 );
return res.quot + rnd.quot;
}
long round_ldiv(long n, long d)
{
ldiv_t res = ldiv(n,d);
ldiv_t rnd = ldiv(res.rem, (abs(d)+1)/2 );
return res.quot + rnd.quot;
}
#ifdef TEST
#include
#include
main(int argc, char *argv[])
{
long n, d, q;
if (argc != 3)
{
puts("Usage: RND_DIV n d\n");
puts("Returns n/d rounded to nearest integer");
return -1;
}
n = atol(argv[1]);
d = atol(argv[2]);
if (n > INT_MAX || d > INT_MAX)
{
q = round_ldiv(n, d);
printf("round_ldiv(%ld, %ld) = %ld\n", n, d, q);
}
else
{
q = (long)round_div((int)n, (int)d);
printf("round_div(%ld, %ld) = %ld\n", n, d, q);
}
return 0;
}
#endif /* TEST */
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/* +++Date last modified: 05-Jul-1997 */
/*
** PARITY.C - Computes even or odd parity for various integral types
**
** public domain demo by Bob Stout
*/
#include "parity.h"
unsigned parity32(unsigned long x, Parity_T even)
{
x = x ^ (x >> 16);
x = x ^ (x >> 8);
x = x ^ (x >> 4);
x = x ^ (x >> 2);
x = x ^ (x >> 1);
return ((unsigned)(x & 1)) ^ even;
}
unsigned parity16(unsigned short x, Parity_T even)
{
x = x ^ (x >> 8);
x = x ^ (x >> 4);
x = x ^ (x >> 2);
x = x ^ (x >> 1);
return ((unsigned)(x & 1)) ^ even;
}
unsigned parity8(unsigned char x, Parity_T even)
{
x = x ^ (x >> 4);
x = x ^ (x >> 2);
x = x ^ (x >> 1);
return ((unsigned)(x & 1)) ^ even;
}
unsigned parity64(void *x, Parity_T even)
{
union longlong *val64 = (union longlong *)x;
return (parity32(val64->lo, even) ^ parity32(val64->hi, even));
}
#ifdef TEST
#include
#include
main(int argc, char *argv[])
{
while (--argc)
{
unsigned long n = strtoul(*(++argv), NULL, 10);
printf("Even parity of %ld = %d\n", n, parity32(n, Even_));
printf("Odd parity of %ld = %d\n\n", n, parity32(n, Odd_));
}
}
#endif