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/*
* Copyright (C) 2014 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 __BYTE_BUCKET_ARRAY_H
#define __BYTE_BUCKET_ARRAY_H
#include <utils/Log.h>
#include <stdint.h>
#include <string.h>
namespace android {
/**
* Stores a sparsely populated array. Has a fixed size of 256
* (number of entries that a byte can represent).
*/
template<typename T>
class ByteBucketArray {
public:
ByteBucketArray() : mDefault() {
memset(mBuckets, 0, sizeof(mBuckets));
}
~ByteBucketArray() {
for (size_t i = 0; i < NUM_BUCKETS; i++) {
if (mBuckets[i] != NULL) {
delete [] mBuckets[i];
}
}
memset(mBuckets, 0, sizeof(mBuckets));
}
inline size_t size() const {
return NUM_BUCKETS * BUCKET_SIZE;
}
inline const T& get(size_t index) const {
return (*this)[index];
}
const T& operator[](size_t index) const {
if (index >= size()) {
return mDefault;
}
uint8_t bucketIndex = static_cast<uint8_t>(index) >> 4;
T* bucket = mBuckets[bucketIndex];
if (bucket == NULL) {
return mDefault;
}
return bucket[0x0f & static_cast<uint8_t>(index)];
}
T& editItemAt(size_t index) {
ALOG_ASSERT(index < size(), "ByteBucketArray.getOrCreate(index=%u) with size=%u",
(uint32_t) index, (uint32_t) size());
uint8_t bucketIndex = static_cast<uint8_t>(index) >> 4;
T* bucket = mBuckets[bucketIndex];
if (bucket == NULL) {
bucket = mBuckets[bucketIndex] = new T[BUCKET_SIZE]();
}
return bucket[0x0f & static_cast<uint8_t>(index)];
}
bool set(size_t index, const T& value) {
if (index >= size()) {
return false;
}
editItemAt(index) = value;
return true;
}
private:
enum { NUM_BUCKETS = 16, BUCKET_SIZE = 16 };
T* mBuckets[NUM_BUCKETS];
T mDefault;
};
} // namespace android
#endif // __BYTE_BUCKET_ARRAY_H
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