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 <androidfw/BigBuffer.h>
18
19 #include <algorithm>
20 #include <iterator>
21 #include <memory>
22
23 #include "android-base/logging.h"
24
25 namespace android {
26
NextBlockImpl(size_t size)27 void* BigBuffer::NextBlockImpl(size_t size) {
28 if (!blocks_.empty()) {
29 Block& block = blocks_.back();
30 if (block.block_size_ - block.size >= size) {
31 void* out_buffer = block.buffer.get() + block.size;
32 block.size += size;
33 size_ += size;
34 return out_buffer;
35 }
36 }
37
38 const size_t actual_size = std::max(block_size_, size);
39
40 Block block = {};
41
42 // Zero-allocate the block's buffer.
43 block.buffer = std::unique_ptr<uint8_t[]>(new uint8_t[actual_size]());
44 CHECK(block.buffer);
45
46 block.size = size;
47 block.block_size_ = actual_size;
48
49 blocks_.push_back(std::move(block));
50 size_ += size;
51 return blocks_.back().buffer.get();
52 }
53
NextBlock(size_t * out_size)54 void* BigBuffer::NextBlock(size_t* out_size) {
55 if (!blocks_.empty()) {
56 Block& block = blocks_.back();
57 if (block.size != block.block_size_) {
58 void* out_buffer = block.buffer.get() + block.size;
59 size_t size = block.block_size_ - block.size;
60 block.size = block.block_size_;
61 size_ += size;
62 *out_size = size;
63 return out_buffer;
64 }
65 }
66
67 // Zero-allocate the block's buffer.
68 Block block = {};
69 block.buffer = std::unique_ptr<uint8_t[]>(new uint8_t[block_size_]());
70 CHECK(block.buffer);
71 block.size = block_size_;
72 block.block_size_ = block_size_;
73 blocks_.push_back(std::move(block));
74 size_ += block_size_;
75 *out_size = block_size_;
76 return blocks_.back().buffer.get();
77 }
78
to_string() const79 std::string BigBuffer::to_string() const {
80 std::string result;
81 result.reserve(size_);
82 for (const Block& block : blocks_) {
83 result.append(block.buffer.get(), block.buffer.get() + block.size);
84 }
85 return result;
86 }
87
AppendBuffer(BigBuffer && buffer)88 void BigBuffer::AppendBuffer(BigBuffer&& buffer) {
89 std::move(buffer.blocks_.begin(), buffer.blocks_.end(), std::back_inserter(blocks_));
90 size_ += buffer.size_;
91 buffer.blocks_.clear();
92 buffer.size_ = 0;
93 }
94
BackUp(size_t count)95 void BigBuffer::BackUp(size_t count) {
96 Block& block = blocks_.back();
97 block.size -= count;
98 size_ -= count;
99 // BigBuffer is supposed to always give zeroed memory, but backing up usually means
100 // something has been already written into the block. Erase it.
101 std::fill_n(block.buffer.get() + block.size, count, 0);
102 }
103
104 } // namespace android
105