include/llvm/Object/Decompressor.h

   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
  16 namespace llvm {
  17 namespace object {
  18
  19 /// Decompressor helps to handle decompression of compressed sections.
  20 class Decompressor {
  21 public:
  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
  53 private:
  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