LCOV - app.info - js/src/jsmath.h

LCOV - code coverage report
| Current view: | directory - js/src - jsmath.h (source / functions) |  | Found | Hit | Coverage |
| Test: | app.info | Lines: | 14 | 14 | 100.0 %
| Date: | 2012-04-07 | Functions: | 3 | 3 | 100.0 %

           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             183 : {
          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         2851242 :     unsigned hash(double x) {
          58         2851242 :         union { double d; struct { uint32_t one, two; } s; } u = { x };
          59         2851242 :         uint32_t hash32 = u.s.one ^ u.s.two;
          60         2851242 :         uint16_t hash16 = uint16_t(hash32 ^ (hash32 >> 16));
          61         2851242 :         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         2850876 :     double lookup(UnaryFunType f, double x) {
          69         2850876 :         unsigned index = hash(x);
          70         2850876 :         Entry &e = table[index];
          71         2850876 :         if (e.in == x && e.f == f)
          72         2003942 :             return e.out;
          73          846934 :         e.in = x;
          74          846934 :         e.f = f;
          75          846934 :         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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