xref: /aosp_15_r20/system/unwinding/libunwindstack/MemoryXz.h (revision eb293b8f56ee8303637c5595cfcdeef8039e85c6)
1 /*
2  * Copyright (C) 2021 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 #pragma once
18 
19 #include <atomic>
20 #include <memory>
21 #include <vector>
22 
23 #include <unwindstack/Memory.h>
24 
25 namespace unwindstack {
26 
27 class MemoryXz : public Memory {
28  public:
29   MemoryXz(Memory* memory, uint64_t addr, uint64_t size, const std::string& name);
30   ~MemoryXz();
31 
32   bool Init();
Size()33   size_t Size() { return size_; }
34   size_t Read(uint64_t addr, void* dst, size_t size) override;
35 
36   // Methods used in tests.
MemoryUsage()37   size_t MemoryUsage() { return used_; }
BlockCount()38   size_t BlockCount() { return blocks_.size(); }
BlockSize()39   size_t BlockSize() { return 1 << block_size_log2_; }
40 
41  private:
42   static constexpr size_t kMaxCompressedSize = 1 << 30;  // 1GB. Arbitrary.
43 
44   struct XzBlock {
45     std::unique_ptr<uint8_t[]> decompressed_data;
46     uint32_t decompressed_size;
47     uint32_t compressed_offset;
48     uint32_t compressed_size;
49     uint16_t stream_flags;
50   };
51   bool ReadBlocks();
52   bool Decompress(XzBlock* block);
53 
54   // Compressed input.
55   Memory* compressed_memory_;
56   uint64_t compressed_addr_;
57   uint64_t compressed_size_;
58   std::string name_;
59 
60   // Decompressed output.
61   std::vector<XzBlock> blocks_;
62   uint32_t used_ = 0;  // Memory usage of the currently decompressed blocks.
63   uint32_t size_ = 0;  // Decompressed size of all blocks.
64   uint32_t block_size_log2_ = 31;
65 
66   // Statistics (used only for optional debug log messages).
67   static std::atomic_size_t total_used_;  // Currently decompressed memory (current memory use).
68   static std::atomic_size_t total_size_;  // Size of mini-debug-info if it was all decompressed.
69   static std::atomic_size_t total_open_;  // Number of mini-debug-info files currently in use.
70 };
71 
72 }  // namespace unwindstack
73