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/*
* Copyright (C) 2009 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 LOCAL_ARRAY_H_included
#define LOCAL_ARRAY_H_included
#include <cstddef>
#include <new>
/**
* A fixed-size array with a size hint. That number of bytes will be allocated
* on the stack, and used if possible, but if more bytes are requested at
* construction time, a buffer will be allocated on the heap (and deallocated
* by the destructor).
*
* The API is intended to be a compatible subset of C++0x's std::array.
*/
template <size_t STACK_BYTE_COUNT>
class LocalArray {
public:
/**
* Allocates a new fixed-size array of the given size. If this size is
* less than or equal to the template parameter STACK_BYTE_COUNT, an
* internal on-stack buffer will be used. Otherwise a heap buffer will
* be allocated.
*/
LocalArray(size_t desiredByteCount) : mSize(desiredByteCount) {
if (desiredByteCount > STACK_BYTE_COUNT) {
mPtr = new char[mSize];
} else {
mPtr = &mOnStackBuffer[0];
}
}
/**
* Frees the heap-allocated buffer, if there was one.
*/
~LocalArray() {
if (mPtr != &mOnStackBuffer[0]) {
delete[] mPtr;
}
}
// Capacity.
size_t size() { return mSize; }
bool empty() { return mSize == 0; }
// Element access.
char& operator[](size_t n) { return mPtr[n]; }
const char& operator[](size_t n) const { return mPtr[n]; }
private:
char mOnStackBuffer[STACK_BYTE_COUNT];
char* mPtr;
size_t mSize;
// Disallow copy and assignment.
LocalArray(const LocalArray&);
void operator=(const LocalArray&);
};
#endif // LOCAL_ARRAY_H_included
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