| Index: Source/WTF/wtf/BloomFilter.h
|
| diff --git a/Source/WTF/wtf/BloomFilter.h b/Source/WTF/wtf/BloomFilter.h
|
| deleted file mode 100644
|
| index 42ba139df7dd552a47b0276831831cca7c1fb1f4..0000000000000000000000000000000000000000
|
| --- a/Source/WTF/wtf/BloomFilter.h
|
| +++ /dev/null
|
| @@ -1,139 +0,0 @@
|
| -/*
|
| - * Copyright (C) 2011 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.
|
| - *
|
| - * THIS SOFTWARE IS PROVIDED BY APPLE INC. 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 INC. 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 BloomFilter_h
|
| -#define BloomFilter_h
|
| -
|
| -#include <wtf/Compiler.h>
|
| -#include <wtf/text/AtomicString.h>
|
| -
|
| -namespace WTF {
|
| -
|
| -// Counting bloom filter with k=2 and 8 bit counters. Uses 2^keyBits bytes of memory.
|
| -// False positive rate is approximately (1-e^(-2n/m))^2, where n is the number of unique
|
| -// keys and m is the table size (==2^keyBits).
|
| -template <unsigned keyBits>
|
| -class BloomFilter {
|
| -public:
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| - COMPILE_ASSERT(keyBits <= 16, bloom_filter_key_size);
|
| -
|
| - static const size_t tableSize = 1 << keyBits;
|
| - static const unsigned keyMask = (1 << keyBits) - 1;
|
| - static uint8_t maximumCount() { return std::numeric_limits<uint8_t>::max(); }
|
| -
|
| - BloomFilter() { clear(); }
|
| -
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| - void add(unsigned hash);
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| - void remove(unsigned hash);
|
| -
|
| - // The filter may give false positives (claim it may contain a key it doesn't)
|
| - // but never false negatives (claim it doesn't contain a key it does).
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| - bool mayContain(unsigned hash) const { return firstSlot(hash) && secondSlot(hash); }
|
| -
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| - // The filter must be cleared before reuse even if all keys are removed.
|
| - // Otherwise overflowed keys will stick around.
|
| - void clear();
|
| -
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| - void add(const AtomicString& string) { add(string.impl()->existingHash()); }
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| - void add(const String& string) { add(string.impl()->hash()); }
|
| - void remove(const AtomicString& string) { remove(string.impl()->existingHash()); }
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| - void remove(const String& string) { remove(string.impl()->hash()); }
|
| -
|
| - bool mayContain(const AtomicString& string) const { return mayContain(string.impl()->existingHash()); }
|
| - bool mayContain(const String& string) const { return mayContain(string.impl()->hash()); }
|
| -
|
| -#if !ASSERT_DISABLED
|
| - // Slow.
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| - bool likelyEmpty() const;
|
| - bool isClear() const;
|
| -#endif
|
| -
|
| -private:
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| - uint8_t& firstSlot(unsigned hash) { return m_table[hash & keyMask]; }
|
| - uint8_t& secondSlot(unsigned hash) { return m_table[(hash >> 16) & keyMask]; }
|
| - const uint8_t& firstSlot(unsigned hash) const { return m_table[hash & keyMask]; }
|
| - const uint8_t& secondSlot(unsigned hash) const { return m_table[(hash >> 16) & keyMask]; }
|
| -
|
| - uint8_t m_table[tableSize];
|
| -};
|
| -
|
| -template <unsigned keyBits>
|
| -inline void BloomFilter<keyBits>::add(unsigned hash)
|
| -{
|
| - uint8_t& first = firstSlot(hash);
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| - uint8_t& second = secondSlot(hash);
|
| - if (LIKELY(first < maximumCount()))
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| - ++first;
|
| - if (LIKELY(second < maximumCount()))
|
| - ++second;
|
| -}
|
| -
|
| -template <unsigned keyBits>
|
| -inline void BloomFilter<keyBits>::remove(unsigned hash)
|
| -{
|
| - uint8_t& first = firstSlot(hash);
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| - uint8_t& second = secondSlot(hash);
|
| - ASSERT(first);
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| - ASSERT(second);
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| - // In case of an overflow, the slot sticks in the table until clear().
|
| - if (LIKELY(first < maximumCount()))
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| - --first;
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| - if (LIKELY(second < maximumCount()))
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| - --second;
|
| -}
|
| -
|
| -template <unsigned keyBits>
|
| -inline void BloomFilter<keyBits>::clear()
|
| -{
|
| - memset(m_table, 0, tableSize);
|
| -}
|
| -
|
| -#if !ASSERT_DISABLED
|
| -template <unsigned keyBits>
|
| -bool BloomFilter<keyBits>::likelyEmpty() const
|
| -{
|
| - for (size_t n = 0; n < tableSize; ++n) {
|
| - if (m_table[n] && m_table[n] != maximumCount())
|
| - return false;
|
| - }
|
| - return true;
|
| -}
|
| -
|
| -template <unsigned keyBits>
|
| -bool BloomFilter<keyBits>::isClear() const
|
| -{
|
| - for (size_t n = 0; n < tableSize; ++n) {
|
| - if (m_table[n])
|
| - return false;
|
| - }
|
| - return true;
|
| -}
|
| -#endif
|
| -
|
| -}
|
| -
|
| -using WTF::BloomFilter;
|
| -
|
| -#endif
|
|
|