1//===-- Decompressor.h ------------------------------------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===/
8
9#ifndef LLVM_OBJECT_DECOMPRESSOR_H
10#define LLVM_OBJECT_DECOMPRESSOR_H
11
12#include "llvm/ADT/SmallString.h"
13#include "llvm/ADT/StringRef.h"
14#include "llvm/Object/ObjectFile.h"
15
16namespace llvm {
17namespace object {
18
19/// Decompressor helps to handle decompression of compressed sections.
20class Decompressor {
21public:
22  /// Create decompressor object.
23  /// @param Name        Section name.
24  /// @param Data        Section content.
25  /// @param IsLE        Flag determines if Data is in little endian form.
26  /// @param Is64Bit     Flag determines if object is 64 bit.
27  static Expected<Decompressor> create(StringRef Name, StringRef Data,
28                                       bool IsLE, bool Is64Bit);
29
30  /// Resize the buffer and uncompress section data into it.
31  /// @param Out         Destination buffer.
32  template <class T> Error resizeAndDecompress(T &Out) {
33    Out.resize(DecompressedSize);
34    return decompress({Out.data(), (size_t)DecompressedSize});
35  }
36
37  /// Uncompress section data to raw buffer provided.
38  /// @param Buffer      Destination buffer.
39  Error decompress(MutableArrayRef<char> Buffer);
40
41  /// Return memory buffer size required for decompression.
42  uint64_t getDecompressedSize() { return DecompressedSize; }
43
44  /// Return true if section is compressed, including gnu-styled case.
45  static bool isCompressed(const object::SectionRef &Section);
46
47  /// Return true if section is a ELF compressed one.
48  static bool isCompressedELFSection(uint64_t Flags, StringRef Name);
49
50  /// Return true if section name matches gnu style compressed one.
51  static bool isGnuStyle(StringRef Name);
52
53private:
54  Decompressor(StringRef Data);
55
56  Error consumeCompressedGnuHeader();
57  Error consumeCompressedZLibHeader(bool Is64Bit, bool IsLittleEndian);
58
59  StringRef SectionData;
60  uint64_t DecompressedSize;
61};
62
63} // end namespace object
64} // end namespace llvm
65
66#endif // LLVM_OBJECT_DECOMPRESSOR_H
67