1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
|
/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is Mozilla Communicator client code, released
* March 31, 1998.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 1998-1999
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
*
* Alternatively, the contents of this file may be used under the terms of
* either of the GNU General Public License Version 2 or later (the "GPL"),
* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#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();
uintN hash(double x) {
union { double d; struct { uint32 one, two; } s; } u = { x };
uint32 hash32 = u.s.one ^ u.s.two;
uint16 hash16 = (uint16)(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) {
uintN 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));
}
};
} /* namespace js */
/*
* JS math functions.
*/
extern js::Class js_MathClass;
extern JSObject *
js_InitMathClass(JSContext *cx, JSObject *obj);
extern bool
js_IsMathFunction(JSNative native);
extern void
js_InitRandom(JSContext *cx);
extern JSBool
js_math_abs(JSContext *cx, uintN argc, js::Value *vp);
extern JSBool
js_math_ceil(JSContext *cx, uintN argc, js::Value *vp);
extern JSBool
js_math_floor(JSContext *cx, uintN argc, js::Value *vp);
extern JSBool
js_math_max(JSContext *cx, uintN argc, js::Value *vp);
extern JSBool
js_math_min(JSContext *cx, uintN argc, js::Value *vp);
extern JSBool
js_math_round(JSContext *cx, uintN argc, js::Value *vp);
extern jsdouble
js_math_ceil_impl(jsdouble x);
extern jsdouble
js_math_floor_impl(jsdouble x);
extern jsdouble
js_math_round_impl(jsdouble x);
#endif /* jsmath_h___ */
|
