BigBuffer.cpp revision 21efb6827cede06c2ab708de6cdb64d052dddcce 
1/*
2 * Copyright (C) 2015 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include "util/BigBuffer.h"
18
19#include <algorithm>
20#include <memory>
21#include <vector>
22
23namespace aapt {
24
25void* BigBuffer::nextBlockImpl(size_t size) {
26    if (!mBlocks.empty()) {
27        Block& block = mBlocks.back();
28        if (block.mBlockSize - block.size >= size) {
29            void* outBuffer = block.buffer.get() + block.size;
30            block.size += size;
31            mSize += size;
32            return outBuffer;
33        }
34    }
35
36    const size_t actualSize = std::max(mBlockSize, size);
37
38    Block block = {};
39
40    // Zero-allocate the block's buffer.
41    block.buffer = std::unique_ptr<uint8_t[]>(new uint8_t[actualSize]());
42    assert(block.buffer);
43
44    block.size = size;
45    block.mBlockSize = actualSize;
46
47    mBlocks.push_back(std::move(block));
48    mSize += size;
49    return mBlocks.back().buffer.get();
50}
51
52void* BigBuffer::nextBlock(size_t* outSize) {
53    if (!mBlocks.empty()) {
54        Block& block = mBlocks.back();
55        if (block.size != block.mBlockSize) {
56            void* outBuffer = block.buffer.get() + block.size;
57            size_t size = block.mBlockSize - block.size;
58            block.size = block.mBlockSize;
59            mSize += size;
60            *outSize = size;
61            return outBuffer;
62        }
63    }
64
65    // Zero-allocate the block's buffer.
66    Block block = {};
67    block.buffer = std::unique_ptr<uint8_t[]>(new uint8_t[mBlockSize]());
68    assert(block.buffer);
69    block.size = mBlockSize;
70    block.mBlockSize = mBlockSize;
71    mBlocks.push_back(std::move(block));
72    mSize += mBlockSize;
73    *outSize = mBlockSize;
74    return mBlocks.back().buffer.get();
75}
76
77} // namespace aapt
78