gecko-dev/js/src/jsmath.h

131 lines
2.9 KiB
C++

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef jsmath_h___
#define jsmath_h___
namespace js {
typedef double (*UnaryFunType)(double);
class MathCache
{
static const unsigned SizeLog2 = 12;
static const unsigned Size = 1 << SizeLog2;
struct Entry { double in; UnaryFunType f; double out; };
Entry table[Size];
public:
MathCache();
unsigned hash(double x) {
union { double d; struct { uint32_t one, two; } s; } u = { x };
uint32_t hash32 = u.s.one ^ u.s.two;
uint16_t hash16 = uint16_t(hash32 ^ (hash32 >> 16));
return (hash16 & (Size - 1)) ^ (hash16 >> (16 - SizeLog2));
}
/*
* N.B. lookup uses double-equality. This is only safe if hash() maps +0
* and -0 to different table entries, which is asserted in MathCache().
*/
double lookup(UnaryFunType f, double x) {
unsigned index = hash(x);
Entry &e = table[index];
if (e.in == x && e.f == f)
return e.out;
e.in = x;
e.f = f;
return (e.out = f(x));
}
size_t sizeOfIncludingThis(JSMallocSizeOfFun mallocSizeOf);
};
} /* namespace js */
/*
* JS math functions.
*/
extern JSObject *
js_InitMathClass(JSContext *cx, js::HandleObject obj);
extern void
js_InitRandom(JSContext *cx);
extern double
math_random_no_outparam(JSContext *cx);
extern JSBool
js_math_random(JSContext *cx, unsigned argc, js::Value *vp);
extern JSBool
js_math_abs(JSContext *cx, unsigned argc, js::Value *vp);
extern JSBool
js_math_ceil(JSContext *cx, unsigned argc, js::Value *vp);
extern JSBool
js_math_floor(JSContext *cx, unsigned argc, js::Value *vp);
extern JSBool
js_math_max(JSContext *cx, unsigned argc, js::Value *vp);
extern JSBool
js_math_min(JSContext *cx, unsigned argc, js::Value *vp);
extern JSBool
js_math_round(JSContext *cx, unsigned argc, js::Value *vp);
extern JSBool
js_math_sqrt(JSContext *cx, unsigned argc, js::Value *vp);
extern JSBool
js_math_pow(JSContext *cx, unsigned argc, js::Value *vp);
extern double
js_math_ceil_impl(double x);
extern double
js_math_floor_impl(double x);
namespace js {
extern JSBool
math_log(JSContext *cx, unsigned argc, js::Value *vp);
extern double
math_log_impl(MathCache *cache, double x);
extern JSBool
math_sin(JSContext *cx, unsigned argc, js::Value *vp);
extern double
math_sin_impl(MathCache *cache, double x);
extern JSBool
math_cos(JSContext *cx, unsigned argc, js::Value *vp);
extern double
math_cos_impl(MathCache *cache, double x);
extern JSBool
math_tan(JSContext *cx, unsigned argc, js::Value *vp);
extern double
math_tan_impl(MathCache *cache, double x);
extern double
powi(double x, int y);
extern double
ecmaPow(double x, double y);
} /* namespace js */
#endif /* jsmath_h___ */