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      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
     67