1 : /* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
2 : *
3 : * ***** BEGIN LICENSE BLOCK *****
4 : * Version: MPL 1.1/GPL 2.0/LGPL 2.1
5 : *
6 : * The contents of this file are subject to the Mozilla Public License Version
7 : * 1.1 (the "License"); you may not use this file except in compliance with
8 : * the License. You may obtain a copy of the License at
9 : * http://www.mozilla.org/MPL/
10 : *
11 : * Software distributed under the License is distributed on an "AS IS" basis,
12 : * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
13 : * for the specific language governing rights and limitations under the
14 : * License.
15 : *
16 : * The Original Code is Mozilla Communicator client code, released
17 : * March 31, 1998.
18 : *
19 : * The Initial Developer of the Original Code is
20 : * Netscape Communications Corporation.
21 : * Portions created by the Initial Developer are Copyright (C) 1998-1999
22 : * the Initial Developer. All Rights Reserved.
23 : *
24 : * Contributor(s):
25 : *
26 : * Alternatively, the contents of this file may be used under the terms of
27 : * either of the GNU General Public License Version 2 or later (the "GPL"),
28 : * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
29 : * in which case the provisions of the GPL or the LGPL are applicable instead
30 : * of those above. If you wish to allow use of your version of this file only
31 : * under the terms of either the GPL or the LGPL, and not to allow others to
32 : * use your version of this file under the terms of the MPL, indicate your
33 : * decision by deleting the provisions above and replace them with the notice
34 : * and other provisions required by the GPL or the LGPL. If you do not delete
35 : * the provisions above, a recipient may use your version of this file under
36 : * the terms of any one of the MPL, the GPL or the LGPL.
37 : *
38 : * ***** END LICENSE BLOCK ***** */
39 :
40 : #ifndef jsmath_h___
41 : #define jsmath_h___
42 :
43 : namespace js {
44 :
45 : typedef double (*UnaryFunType)(double);
46 :
47 : class MathCache
48 174 : {
49 : static const unsigned SizeLog2 = 12;
50 : static const unsigned Size = 1 << SizeLog2;
51 : struct Entry { double in; UnaryFunType f; double out; };
52 : Entry table[Size];
53 :
54 : public:
55 : MathCache();
56 :
57 2851215 : unsigned hash(double x) {
58 2851215 : union { double d; struct { uint32_t one, two; } s; } u = { x };
59 2851215 : uint32_t hash32 = u.s.one ^ u.s.two;
60 2851215 : uint16_t hash16 = uint16_t(hash32 ^ (hash32 >> 16));
61 2851215 : return (hash16 & (Size - 1)) ^ (hash16 >> (16 - SizeLog2));
62 : }
63 :
64 : /*
65 : * N.B. lookup uses double-equality. This is only safe if hash() maps +0
66 : * and -0 to different table entries, which is asserted in MathCache().
67 : */
68 2850867 : double lookup(UnaryFunType f, double x) {
69 2850867 : unsigned index = hash(x);
70 2850867 : Entry &e = table[index];
71 2850867 : if (e.in == x && e.f == f)
72 2003942 : return e.out;
73 846925 : e.in = x;
74 846925 : e.f = f;
75 846925 : return (e.out = f(x));
76 : }
77 : };
78 :
79 : } /* namespace js */
80 :
81 : /*
82 : * JS math functions.
83 : */
84 :
85 : extern JSObject *
86 : js_InitMathClass(JSContext *cx, JSObject *obj);
87 :
88 : extern bool
89 : js_IsMathFunction(JSNative native);
90 :
91 : extern void
92 : js_InitRandom(JSContext *cx);
93 :
94 : extern JSBool
95 : js_math_abs(JSContext *cx, unsigned argc, js::Value *vp);
96 :
97 : extern JSBool
98 : js_math_ceil(JSContext *cx, unsigned argc, js::Value *vp);
99 :
100 : extern JSBool
101 : js_math_floor(JSContext *cx, unsigned argc, js::Value *vp);
102 :
103 : extern JSBool
104 : js_math_max(JSContext *cx, unsigned argc, js::Value *vp);
105 :
106 : extern JSBool
107 : js_math_min(JSContext *cx, unsigned argc, js::Value *vp);
108 :
109 : extern JSBool
110 : js_math_round(JSContext *cx, unsigned argc, js::Value *vp);
111 :
112 : extern JSBool
113 : js_math_sqrt(JSContext *cx, unsigned argc, js::Value *vp);
114 :
115 : extern JSBool
116 : js_math_pow(JSContext *cx, unsigned argc, js::Value *vp);
117 :
118 : extern double
119 : js_math_ceil_impl(double x);
120 :
121 : extern double
122 : js_math_floor_impl(double x);
123 :
124 : #endif /* jsmath_h___ */
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