02c9460a0a
Using __builtin_c{l,t}zl fails on 64b systems as unsigned long is
8B there. However, unsigned int is only guaranteed to be 2B. Introduce
a check that should be optimized away by the compiler.
Change-Id: I854d0817c6bb5ae13c257241240664bf8f1a7c8a
294 lines
11 KiB
C++
294 lines
11 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(0UL) { }
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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 0x80000000UL >> n; }
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// Clears the bit set.
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inline void clear() { clear(value); }
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static inline void clear(uint32_t& value) { value = 0UL; }
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// Returns the number of marked bits in the set.
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inline uint32_t count() const { return count(value); }
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static inline uint32_t count(uint32_t value) { return __builtin_popcountl(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 isEmpty(value); }
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static inline bool isEmpty(uint32_t value) { 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 isFull(value); }
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static inline bool isFull(uint32_t value) { return value == 0xffffffffUL; }
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// Returns true if the specified bit is marked.
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inline bool hasBit(uint32_t n) const { return hasBit(value, n); }
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static inline bool hasBit(uint32_t value, uint32_t n) { return value & valueForBit(n); }
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// Marks the specified bit.
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inline void markBit(uint32_t n) { markBit(value, n); }
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static inline void markBit (uint32_t& value, uint32_t n) { value |= valueForBit(n); }
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// Clears the specified bit.
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inline void clearBit(uint32_t n) { clearBit(value, n); }
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static inline void clearBit(uint32_t& value, 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 firstMarkedBit(value); }
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static uint32_t firstMarkedBit(uint32_t value) { return clz_checked(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 firstUnmarkedBit(value); }
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static inline uint32_t firstUnmarkedBit(uint32_t value) { return clz_checked(~ 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 lastMarkedBit(value); }
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static inline uint32_t lastMarkedBit(uint32_t value) { return 31 - ctz_checked(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() { return clearFirstMarkedBit(value); }
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static inline uint32_t clearFirstMarkedBit(uint32_t& value) {
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uint32_t n = firstMarkedBit(value);
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clearBit(value, 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() { return markFirstUnmarkedBit(value); }
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static inline uint32_t markFirstUnmarkedBit(uint32_t& value) {
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uint32_t n = firstUnmarkedBit(value);
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markBit(value, 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() { return clearLastMarkedBit(value); }
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static inline uint32_t clearLastMarkedBit(uint32_t& value) {
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uint32_t n = lastMarkedBit(value);
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clearBit(value, 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 getIndexOfBit(value, n);
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}
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static inline uint32_t getIndexOfBit(uint32_t value, uint32_t n) {
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return __builtin_popcountl(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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private:
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// We use these helpers as the signature of __builtin_c{l,t}z has "unsigned int" for the
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// input, which is only guaranteed to be 16b, not 32. The compiler should optimize this away.
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static inline uint32_t clz_checked(uint32_t value) {
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if (sizeof(unsigned int) == sizeof(uint32_t)) {
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return __builtin_clz(value);
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} else {
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return __builtin_clzl(value);
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}
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}
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static inline uint32_t ctz_checked(uint32_t value) {
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if (sizeof(unsigned int) == sizeof(uint32_t)) {
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return __builtin_ctz(value);
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} else {
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return __builtin_ctzl(value);
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}
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}
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};
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ANDROID_BASIC_TYPES_TRAITS(BitSet32)
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// A simple set of 64 bits that can be individually marked or cleared.
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struct BitSet64 {
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uint64_t value;
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inline BitSet64() : value(0ULL) { }
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explicit inline BitSet64(uint64_t value) : value(value) { }
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// Gets the value associated with a particular bit index.
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static inline uint64_t valueForBit(uint32_t n) { return 0x8000000000000000ULL >> n; }
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// Clears the bit set.
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inline void clear() { clear(value); }
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static inline void clear(uint64_t& value) { value = 0ULL; }
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// Returns the number of marked bits in the set.
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inline uint32_t count() const { return count(value); }
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static inline uint32_t count(uint64_t value) { return __builtin_popcountll(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 isEmpty(value); }
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static inline bool isEmpty(uint64_t value) { 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 isFull(value); }
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static inline bool isFull(uint64_t value) { return value == 0xffffffffffffffffULL; }
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// Returns true if the specified bit is marked.
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inline bool hasBit(uint32_t n) const { return hasBit(value, n); }
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static inline bool hasBit(uint64_t value, uint32_t n) { return value & valueForBit(n); }
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// Marks the specified bit.
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inline void markBit(uint32_t n) { markBit(value, n); }
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static inline void markBit(uint64_t& value, uint32_t n) { value |= valueForBit(n); }
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// Clears the specified bit.
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inline void clearBit(uint32_t n) { clearBit(value, n); }
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static inline void clearBit(uint64_t& value, 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 firstMarkedBit(value); }
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static inline uint32_t firstMarkedBit(uint64_t value) { return __builtin_clzll(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 firstUnmarkedBit(value); }
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static inline uint32_t firstUnmarkedBit(uint64_t value) { return __builtin_clzll(~ 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 lastMarkedBit(value); }
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static inline uint32_t lastMarkedBit(uint64_t value) { return 63 - __builtin_ctzll(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() { return clearFirstMarkedBit(value); }
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static inline uint32_t clearFirstMarkedBit(uint64_t& value) {
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uint64_t n = firstMarkedBit(value);
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clearBit(value, 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() { return markFirstUnmarkedBit(value); }
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static inline uint32_t markFirstUnmarkedBit(uint64_t& value) {
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uint64_t n = firstUnmarkedBit(value);
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markBit(value, 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() { return clearLastMarkedBit(value); }
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static inline uint32_t clearLastMarkedBit(uint64_t& value) {
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uint64_t n = lastMarkedBit(value);
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clearBit(value, 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 { return getIndexOfBit(value, n); }
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static inline uint32_t getIndexOfBit(uint64_t value, uint32_t n) {
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return __builtin_popcountll(value & ~(0xffffffffffffffffULL >> n));
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}
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inline bool operator== (const BitSet64& other) const { return value == other.value; }
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inline bool operator!= (const BitSet64& other) const { return value != other.value; }
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inline BitSet64 operator& (const BitSet64& other) const {
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return BitSet64(value & other.value);
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}
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inline BitSet64& operator&= (const BitSet64& other) {
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value &= other.value;
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return *this;
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}
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inline BitSet64 operator| (const BitSet64& other) const {
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return BitSet64(value | other.value);
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}
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inline BitSet64& operator|= (const BitSet64& 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(BitSet64)
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} // namespace android
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#endif // UTILS_BITSET_H
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