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add fac and infs/combinatoric test

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chendotjs
2017-03-15 18:25:37 +08:00
parent 5dc1f2bcdc
commit 94fe42391c
2 changed files with 81 additions and 0 deletions
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21
tinyexpr.c
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@@ -39,11 +39,17 @@ For log = natural log uncomment the next line. */
#include <math.h>
#include <string.h>
#include <stdio.h>
#include <limits.h>
#ifndef NAN
#define NAN (0.0/0.0)
#endif
#ifndef INFINITY
#define INFINITY (1.0/0.0)
#endif
typedef double (*te_fun2)(double, double);
enum {
@@ -113,6 +119,20 @@ void te_free(te_expr *n) {
static double pi() {return 3.14159265358979323846;}
static double e() {return 2.71828182845904523536;}
static double fac(double a) {/* simplest version of fac */
if (a < 0.0)
return NAN;
if (a > UINT_MAX)
return INFINITY;
unsigned int ua = (unsigned int)(a);
unsigned long int result = 1, i = 1;
for (i = 1; i <= ua; i++) {
if (ua > ULONG_MAX / result)
return INFINITY;
result *= i;
}
return (double)result;
}
static const te_variable functions[] = {
/* must be in alphabetical order */
@@ -126,6 +146,7 @@ static const te_variable functions[] = {
{"cosh", cosh, TE_FUNCTION1 | TE_FLAG_PURE, 0},
{"e", e, TE_FUNCTION0 | TE_FLAG_PURE, 0},
{"exp", exp, TE_FUNCTION1 | TE_FLAG_PURE, 0},
{"fac", fac, TE_FUNCTION1 | TE_FLAG_PURE, 0},
{"floor", floor, TE_FUNCTION1 | TE_FLAG_PURE, 0},
{"ln", log, TE_FUNCTION1 | TE_FLAG_PURE, 0},
#ifdef TE_NAT_LOG