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: 2012-06-02 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             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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