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Diffstat (limited to 'Source/JavaScriptCore/wtf/Bitmap.h')
-rw-r--r-- | Source/JavaScriptCore/wtf/Bitmap.h | 225 |
1 files changed, 0 insertions, 225 deletions
diff --git a/Source/JavaScriptCore/wtf/Bitmap.h b/Source/JavaScriptCore/wtf/Bitmap.h deleted file mode 100644 index 76a2ca4b3..000000000 --- a/Source/JavaScriptCore/wtf/Bitmap.h +++ /dev/null @@ -1,225 +0,0 @@ -/* - * Copyright (C) 2010 Apple Inc. All rights reserved. - * - * This library is free software; you can redistribute it and/or - * modify it under the terms of the GNU Lesser General Public - * License as published by the Free Software Foundation; either - * version 2 of the License, or (at your option) any later version. - * - * This library is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - * Lesser General Public License for more details. - * - * You should have received a copy of the GNU Lesser General Public - * License along with this library; if not, write to the Free Software - * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA - * - */ -#ifndef Bitmap_h -#define Bitmap_h - -#include <wtf/Atomics.h> -#include <wtf/FixedArray.h> -#include <wtf/StdLibExtras.h> -#include <stdint.h> -#include <string.h> - -namespace WTF { - -enum BitmapAtomicMode { - // This makes concurrentTestAndSet behave just like testAndSet. - BitmapNotAtomic, - - // This makes concurrentTestAndSet use compareAndSwap, so that it's - // atomic even when used concurrently. - BitmapAtomic -}; - -template<size_t size, BitmapAtomicMode atomicMode = BitmapNotAtomic> -class Bitmap { -private: - typedef uint32_t WordType; - -public: - Bitmap(); - - bool get(size_t) const; - void set(size_t); - bool testAndSet(size_t); - bool testAndClear(size_t); - bool concurrentTestAndSet(size_t); - bool concurrentTestAndClear(size_t); - size_t nextPossiblyUnset(size_t) const; - void clear(size_t); - void clearAll(); - int64_t findRunOfZeros(size_t) const; - size_t count(size_t = 0) const; - size_t isEmpty() const; - size_t isFull() const; - -private: - static const WordType wordSize = sizeof(WordType) * 8; - static const WordType words = (size + wordSize - 1) / wordSize; - - // the literal '1' is of type signed int. We want to use an unsigned - // version of the correct size when doing the calculations because if - // WordType is larger than int, '1 << 31' will first be sign extended - // and then casted to unsigned, meaning that set(31) when WordType is - // a 64 bit unsigned int would give 0xffff8000 - static const WordType one = 1; - - FixedArray<WordType, words> bits; -}; - -template<size_t size, BitmapAtomicMode atomicMode> -inline Bitmap<size, atomicMode>::Bitmap() -{ - clearAll(); -} - -template<size_t size, BitmapAtomicMode atomicMode> -inline bool Bitmap<size, atomicMode>::get(size_t n) const -{ - return !!(bits[n / wordSize] & (one << (n % wordSize))); -} - -template<size_t size, BitmapAtomicMode atomicMode> -inline void Bitmap<size, atomicMode>::set(size_t n) -{ - bits[n / wordSize] |= (one << (n % wordSize)); -} - -template<size_t size, BitmapAtomicMode atomicMode> -inline bool Bitmap<size, atomicMode>::testAndSet(size_t n) -{ - WordType mask = one << (n % wordSize); - size_t index = n / wordSize; - bool result = bits[index] & mask; - bits[index] |= mask; - return result; -} - -template<size_t size, BitmapAtomicMode atomicMode> -inline bool Bitmap<size, atomicMode>::testAndClear(size_t n) -{ - WordType mask = one << (n % wordSize); - size_t index = n / wordSize; - bool result = bits[index] & mask; - bits[index] &= ~mask; - return result; -} - -template<size_t size, BitmapAtomicMode atomicMode> -inline bool Bitmap<size, atomicMode>::concurrentTestAndSet(size_t n) -{ - if (atomicMode == BitmapNotAtomic) - return testAndSet(n); - - ASSERT(atomicMode == BitmapAtomic); - - WordType mask = one << (n % wordSize); - size_t index = n / wordSize; - WordType* wordPtr = bits.data() + index; - WordType oldValue; - do { - oldValue = *wordPtr; - if (oldValue & mask) - return true; - } while (!weakCompareAndSwap(wordPtr, oldValue, oldValue | mask)); - return false; -} - -template<size_t size, BitmapAtomicMode atomicMode> -inline bool Bitmap<size, atomicMode>::concurrentTestAndClear(size_t n) -{ - if (atomicMode == BitmapNotAtomic) - return testAndClear(n); - - ASSERT(atomicMode == BitmapAtomic); - - WordType mask = one << (n % wordSize); - size_t index = n / wordSize; - WordType* wordPtr = bits.data() + index; - WordType oldValue; - do { - oldValue = *wordPtr; - if (!(oldValue & mask)) - return false; - } while (!weakCompareAndSwap(wordPtr, oldValue, oldValue & ~mask)); - return true; -} - -template<size_t size, BitmapAtomicMode atomicMode> -inline void Bitmap<size, atomicMode>::clear(size_t n) -{ - bits[n / wordSize] &= ~(one << (n % wordSize)); -} - -template<size_t size, BitmapAtomicMode atomicMode> -inline void Bitmap<size, atomicMode>::clearAll() -{ - memset(bits.data(), 0, sizeof(bits)); -} - -template<size_t size, BitmapAtomicMode atomicMode> -inline size_t Bitmap<size, atomicMode>::nextPossiblyUnset(size_t start) const -{ - if (!~bits[start / wordSize]) - return ((start / wordSize) + 1) * wordSize; - return start + 1; -} - -template<size_t size, BitmapAtomicMode atomicMode> -inline int64_t Bitmap<size, atomicMode>::findRunOfZeros(size_t runLength) const -{ - if (!runLength) - runLength = 1; - - for (size_t i = 0; i <= (size - runLength) ; i++) { - bool found = true; - for (size_t j = i; j <= (i + runLength - 1) ; j++) { - if (get(j)) { - found = false; - break; - } - } - if (found) - return i; - } - return -1; -} - -template<size_t size, BitmapAtomicMode atomicMode> -inline size_t Bitmap<size, atomicMode>::count(size_t start) const -{ - size_t result = 0; - for ( ; (start % wordSize); ++start) { - if (get(start)) - ++result; - } - for (size_t i = start / wordSize; i < words; ++i) - result += WTF::bitCount(bits[i]); - return result; -} - -template<size_t size, BitmapAtomicMode atomicMode> -inline size_t Bitmap<size, atomicMode>::isEmpty() const -{ - for (size_t i = 0; i < words; ++i) - if (bits[i]) - return false; - return true; -} - -template<size_t size, BitmapAtomicMode atomicMode> -inline size_t Bitmap<size, atomicMode>::isFull() const -{ - for (size_t i = 0; i < words; ++i) - if (~bits[i]) - return false; - return true; -} - -} -#endif |