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