124 lines
4.1 KiB
C++
124 lines
4.1 KiB
C++
/*
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* Copyright (C) 2010 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef UTILS_BITSET_H
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#define UTILS_BITSET_H
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#include <stdint.h>
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#include <utils/TypeHelpers.h>
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/*
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* Contains some bit manipulation helpers.
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*/
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namespace android {
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// A simple set of 32 bits that can be individually marked or cleared.
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struct BitSet32 {
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uint32_t value;
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inline BitSet32() : value(0) { }
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explicit inline BitSet32(uint32_t value) : value(value) { }
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// Gets the value associated with a particular bit index.
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static inline uint32_t valueForBit(uint32_t n) { return 0x80000000 >> n; }
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// Clears the bit set.
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inline void clear() { value = 0; }
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// Returns the number of marked bits in the set.
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inline uint32_t count() const { return __builtin_popcount(value); }
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// Returns true if the bit set does not contain any marked bits.
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inline bool isEmpty() const { return ! value; }
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// Returns true if the bit set does not contain any unmarked bits.
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inline bool isFull() const { return value == 0xffffffff; }
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// Returns true if the specified bit is marked.
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inline bool hasBit(uint32_t n) const { return value & valueForBit(n); }
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// Marks the specified bit.
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inline void markBit(uint32_t n) { value |= valueForBit(n); }
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// Clears the specified bit.
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inline void clearBit(uint32_t n) { value &= ~ valueForBit(n); }
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// Finds the first marked bit in the set.
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// Result is undefined if all bits are unmarked.
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inline uint32_t firstMarkedBit() const { return __builtin_clz(value); }
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// Finds the first unmarked bit in the set.
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// Result is undefined if all bits are marked.
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inline uint32_t firstUnmarkedBit() const { return __builtin_clz(~ value); }
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// Finds the last marked bit in the set.
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// Result is undefined if all bits are unmarked.
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inline uint32_t lastMarkedBit() const { return 31 - __builtin_ctz(value); }
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// Finds the first marked bit in the set and clears it. Returns the bit index.
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// Result is undefined if all bits are unmarked.
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inline uint32_t clearFirstMarkedBit() {
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uint32_t n = firstMarkedBit();
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clearBit(n);
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return n;
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}
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// Finds the first unmarked bit in the set and marks it. Returns the bit index.
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// Result is undefined if all bits are marked.
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inline uint32_t markFirstUnmarkedBit() {
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uint32_t n = firstUnmarkedBit();
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markBit(n);
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return n;
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}
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// Finds the last marked bit in the set and clears it. Returns the bit index.
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// Result is undefined if all bits are unmarked.
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inline uint32_t clearLastMarkedBit() {
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uint32_t n = lastMarkedBit();
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clearBit(n);
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return n;
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}
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// Gets the index of the specified bit in the set, which is the number of
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// marked bits that appear before the specified bit.
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inline uint32_t getIndexOfBit(uint32_t n) const {
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return __builtin_popcount(value & ~(0xffffffffUL >> n));
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}
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inline bool operator== (const BitSet32& other) const { return value == other.value; }
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inline bool operator!= (const BitSet32& other) const { return value != other.value; }
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inline BitSet32 operator& (const BitSet32& other) const {
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return BitSet32(value & other.value);
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}
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inline BitSet32& operator&= (const BitSet32& other) {
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value &= other.value;
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return *this;
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}
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inline BitSet32 operator| (const BitSet32& other) const {
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return BitSet32(value | other.value);
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}
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inline BitSet32& operator|= (const BitSet32& other) {
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value |= other.value;
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return *this;
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}
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};
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ANDROID_BASIC_TYPES_TRAITS(BitSet32)
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} // namespace android
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#endif // UTILS_BITSET_H
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