runtime/PropertyName.h

   1 /*
   2  * Copyright (C) 2012 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. AND ITS CONTRIBUTORS ``AS IS''
  14  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  15  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  16  * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
  17  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  18  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  19  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  20  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  21  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  22  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
  23  * THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #ifndef PropertyName_h
  27 #define PropertyName_h
  28
  29 #include "Identifier.h"
  30 #include "PrivateName.h"
  31
  32 namespace JSC {
  33
  34 template <typename CharType>
  35 ALWAYS_INLINE uint32_t toUInt32FromCharacters(const CharType* characters, unsigned length)
  36 {
  37     // An empty string is not a number.
  38     if (!length)
  39         return UINT_MAX;
  40
  41     // Get the first character, turning it into a digit.
  42     uint32_t value = characters[0] - '0';
  43     if (value > 9)
  44         return UINT_MAX;
  45
  46     // Check for leading zeros. If the first characher is 0, then the
  47     // length of the string must be one - e.g. "042" is not equal to "42".
  48     if (!value && length > 1)
  49         return UINT_MAX;
  50
  51     while (--length) {
  52         // Multiply value by 10, checking for overflow out of 32 bits.
  53         if (value > 0xFFFFFFFFU / 10)
  54             return UINT_MAX;
  55         value *= 10;
  56
  57         // Get the next character, turning it into a digit.
  58         uint32_t newValue = *(++characters) - '0';
  59         if (newValue > 9)
  60             return UINT_MAX;
  61
  62         // Add in the old value, checking for overflow out of 32 bits.
  63         newValue += value;
  64         if (newValue < value)
  65             return UINT_MAX;
  66         value = newValue;
  67     }
  68
  69     return value;
  70 }
  71
  72 ALWAYS_INLINE uint32_t toUInt32FromStringImpl(StringImpl* impl)
  73 {
  74     if (impl->is8Bit())
  75         return toUInt32FromCharacters(impl->characters8(), impl->length());
  76     return toUInt32FromCharacters(impl->characters16(), impl->length());
  77 }
  78
  79 class PropertyName {
  80 public:
  81     PropertyName(const Identifier& propertyName)
  82         : m_impl(propertyName.impl())
  83     {
  84         ASSERT(!m_impl || m_impl->isAtomic());
  85     }
  86
  87     PropertyName(const PrivateName& propertyName)
  88         : m_impl(propertyName.uid())
  89     {
  90         ASSERT(m_impl && m_impl->isEmptyUnique());
  91     }
  92
  93     StringImpl* uid() const
  94     {
  95         return m_impl;
  96     }
  97
  98     StringImpl* publicName() const
  99     {
 100         return m_impl->isEmptyUnique() ? 0 : m_impl;
 101     }
 102
 103     static const uint32_t NotAnIndex = UINT_MAX;
 104
 105     uint32_t asIndex()
 106     {
 107         return m_impl ? toUInt32FromStringImpl(m_impl) : NotAnIndex;
 108     }
 109
 110 private:
 111     StringImpl* m_impl;
 112 };
 113
 114 inline bool operator==(PropertyName a, const Identifier& b)
 115 {
 116     return a.uid() == b.impl();
 117 }
 118
 119 inline bool operator==(const Identifier& a, PropertyName b)
 120 {
 121     return a.impl() == b.uid();
 122 }
 123
 124 inline bool operator==(PropertyName a, PropertyName b)
 125 {
 126     return a.uid() == b.uid();
 127 }
 128
 129 inline bool operator!=(PropertyName a, const Identifier& b)
 130 {
 131     return a.uid() != b.impl();
 132 }
 133
 134 inline bool operator!=(const Identifier& a, PropertyName b)
 135 {
 136     return a.impl() != b.uid();
 137 }
 138
 139 inline bool operator!=(PropertyName a, PropertyName b)
 140 {
 141     return a.uid() != b.uid();
 142 }
 143
 144 }
 145
 146 #endif