runtime/NumericStrings.h

   1 /*
   2  * Copyright (C) 2009 Apple Inc. All Rights Reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  *
  13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
  14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
  17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #ifndef NumericStrings_h
  27 #define NumericStrings_h
  28
  29 #include "UString.h"
  30 #include <wtf/HashFunctions.h>
  31
  32 namespace JSC {
  33
  34     class NumericStrings {
  35     public:
  36         UString add(double d)
  37         {
  38             CacheEntry<double>& entry = lookup(d);
  39             if (d == entry.key && !entry.value.isNull())
  40                 return entry.value;
  41             entry.key = d;
  42             entry.value = UString::from(d);
  43             return entry.value;
  44         }
  45
  46         UString add(int i)
  47         {
  48             CacheEntry<int>& entry = lookup(i);
  49             if (i == entry.key && !entry.value.isNull())
  50                 return entry.value;
  51             entry.key = i;
  52             entry.value = UString::from(i);
  53             return entry.value;
  54         }
  55
  56     private:
  57         static const size_t cacheSize = 64;
  58
  59         template<typename T>
  60         struct CacheEntry {
  61             T key;
  62             UString value;
  63         };
  64
  65         CacheEntry<double>& lookup(double d) { return doubleCache[WTF::FloatHash<double>::hash(d) & (cacheSize - 1)]; }
  66         CacheEntry<int>& lookup(int i) { return intCache[WTF::IntHash<int>::hash(i) & (cacheSize - 1)]; }
  67
  68         CacheEntry<double> doubleCache[cacheSize];
  69         CacheEntry<int> intCache[cacheSize];
  70     };
  71
  72 } // namespace JSC
  73
  74 #endif // NumericStrings_h