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author | The Android Open Source Project <initial-contribution@android.com> | 2009-03-03 19:30:52 -0800 |
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committer | The Android Open Source Project <initial-contribution@android.com> | 2009-03-03 19:30:52 -0800 |
commit | 8e35f3cfc7fba1d1c829dc557ebad6409cbe16a2 (patch) | |
tree | 11425ea0b299d6fb89c6d3618a22d97d5bf68d0f /JavaScriptCore/runtime/SymbolTable.h | |
parent | 648161bb0edfc3d43db63caed5cc5213bc6cb78f (diff) | |
download | external_webkit-8e35f3cfc7fba1d1c829dc557ebad6409cbe16a2.zip external_webkit-8e35f3cfc7fba1d1c829dc557ebad6409cbe16a2.tar.gz external_webkit-8e35f3cfc7fba1d1c829dc557ebad6409cbe16a2.tar.bz2 |
auto import from //depot/cupcake/@135843
Diffstat (limited to 'JavaScriptCore/runtime/SymbolTable.h')
-rw-r--r-- | JavaScriptCore/runtime/SymbolTable.h | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/JavaScriptCore/runtime/SymbolTable.h b/JavaScriptCore/runtime/SymbolTable.h new file mode 100644 index 0000000..d730d58 --- /dev/null +++ b/JavaScriptCore/runtime/SymbolTable.h @@ -0,0 +1,126 @@ +/* + * Copyright (C) 2007, 2008 Apple Inc. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of + * its contributors may be used to endorse or promote products derived + * from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY + * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED + * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE + * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY + * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES + * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; + * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND + * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#ifndef SymbolTable_h +#define SymbolTable_h + +#include "JSObject.h" +#include "ustring.h" +#include <wtf/AlwaysInline.h> + +namespace JSC { + + static ALWAYS_INLINE int missingSymbolMarker() { return std::numeric_limits<int>::max(); } + + // The bit twiddling in this class assumes that every register index is a + // reasonably small positive or negative number, and therefore has its high + // four bits all set or all unset. + + struct SymbolTableEntry { + SymbolTableEntry() + : m_bits(0) + { + } + + SymbolTableEntry(int index) + { + ASSERT(isValidIndex(index)); + pack(index, false, false); + } + + SymbolTableEntry(int index, unsigned attributes) + { + ASSERT(isValidIndex(index)); + pack(index, attributes & ReadOnly, attributes & DontEnum); + } + + bool isNull() const + { + return !m_bits; + } + + int getIndex() const + { + return m_bits >> FlagBits; + } + + unsigned getAttributes() const + { + unsigned attributes = 0; + if (m_bits & ReadOnlyFlag) + attributes |= ReadOnly; + if (m_bits & DontEnumFlag) + attributes |= DontEnum; + return attributes; + } + + void setAttributes(unsigned attributes) + { + pack(getIndex(), attributes & ReadOnly, attributes & DontEnum); + } + + bool isReadOnly() const + { + return m_bits & ReadOnlyFlag; + } + + private: + static const unsigned ReadOnlyFlag = 0x1; + static const unsigned DontEnumFlag = 0x2; + static const unsigned NotNullFlag = 0x4; + static const unsigned FlagBits = 3; + + void pack(int index, bool readOnly, bool dontEnum) + { + m_bits = (index << FlagBits) | NotNullFlag; + if (readOnly) + m_bits |= ReadOnlyFlag; + if (dontEnum) + m_bits |= DontEnumFlag; + } + + bool isValidIndex(int index) + { + return ((index << FlagBits) >> FlagBits) == index; + } + + int m_bits; + }; + + struct SymbolTableIndexHashTraits { + typedef SymbolTableEntry TraitType; + static SymbolTableEntry emptyValue() { return SymbolTableEntry(); } + static const bool emptyValueIsZero = true; + static const bool needsDestruction = false; + }; + + typedef HashMap<RefPtr<UString::Rep>, SymbolTableEntry, IdentifierRepHash, HashTraits<RefPtr<UString::Rep> >, SymbolTableIndexHashTraits> SymbolTable; + +} // namespace JSC + +#endif // SymbolTable_h |