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Diffstat (limited to 'include/utils/BitSet.h')
-rw-r--r-- | include/utils/BitSet.h | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/include/utils/BitSet.h b/include/utils/BitSet.h new file mode 100644 index 0000000..19c8bf0 --- /dev/null +++ b/include/utils/BitSet.h @@ -0,0 +1,67 @@ +/* + * Copyright (C) 2010 The Android Open Source Project + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#ifndef UTILS_BITSET_H +#define UTILS_BITSET_H + +#include <stdint.h> + +/* + * Contains some bit manipulation helpers. + */ + +namespace android { + +// A simple set of 32 bits that can be individually marked or cleared. +struct BitSet32 { + uint32_t value; + + inline BitSet32() : value(0) { } + explicit inline BitSet32(uint32_t value) : value(value) { } + + // Gets the value associated with a particular bit index. + static inline uint32_t valueForBit(uint32_t n) { return 0x80000000 >> n; } + + // Clears the bit set. + inline void clear() { value = 0; } + + // Returns true if the bit set does not contain any marked bits. + inline bool isEmpty() const { return ! value; } + + // Returns true if the specified bit is marked. + inline bool hasBit(uint32_t n) const { return value & valueForBit(n); } + + // Marks the specified bit. + inline void markBit(uint32_t n) { value |= valueForBit(n); } + + // Clears the specified bit. + inline void clearBit(uint32_t n) { value &= ~ valueForBit(n); } + + // Finds the first marked bit in the set. + // Result is undefined if all bits are unmarked. + inline uint32_t firstMarkedBit() const { return __builtin_clz(value); } + + // Finds the first unmarked bit in the set. + // Result is undefined if all bits are marked. + inline uint32_t firstUnmarkedBit() const { return __builtin_clz(~ value); } + + inline bool operator== (const BitSet32& other) const { return value == other.value; } + inline bool operator!= (const BitSet32& other) const { return value != other.value; } +}; + +} // namespace android + +#endif // UTILS_BITSET_H |