[Courgette] Clean up Disassembler; fix ELF Memory leaks.

courgette/disassembler.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef COURGETTE_DISASSEMBLER_H_
 #define COURGETTE_DISASSEMBLER_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include "base/macros.h"
 #include "courgette/courgette.h"
 #include "courgette/image_utils.h"
 
 namespace courgette {
 
 class AssemblyProgram;
 
-class Disassembler {
+class Disassembler : public AddressTranslator {
  public:
   virtual ~Disassembler();
 
-  virtual ExecutableType kind() { return EXE_UNKNOWN; }
+  // AddressTranslator interfaces.
+  virtual RVA FileOffsetToRVA(FileOffset file_offset) const override = 0;
+  virtual FileOffset RVAToFileOffset(RVA rva) const override = 0;
+  const uint8_t* FileOffsetToPointer(FileOffset file_offset) const override;
+  const uint8_t* RVAToPointer(RVA rva) const override;
 
-  // ok() may always be called but returns 'true' only after ParseHeader
-  // succeeds.
-  bool ok() const { return failure_reason_ == NULL; }
+  virtual ExecutableType kind() const = 0;
 
-  // Returns 'true' if the buffer appears to be a valid executable of the
-  // expected type. It is not required that this be called before Disassemble.
+  // Returns true if the buffer appears to be a valid executable of the expected
+  // type, and false otherwise. This needs not be called before Disassemble().
   virtual bool ParseHeader() = 0;
 
   // Disassembles the item passed to the factory method into the output
   // parameter 'program'.
   virtual bool Disassemble(AssemblyProgram* program) = 0;
 
-  // Returns the length of the source executable. May reduce after ParseHeader.
+  // ok() may always be called but returns true only after ParseHeader()
+  // succeeds.
+  bool ok() const { return failure_reason_ == nullptr; }
+
+  // Returns the length of the image. May reduce after ParseHeader().
   size_t length() const { return length_; }
   const uint8_t* start() const { return start_; }
   const uint8_t* end() const { return end_; }
 
-  // Returns a pointer into the memory copy of the file format.
-  // FileOffsetToPointer(0) returns a pointer to the start of the file format.
-  const uint8_t* OffsetToPointer(size_t offset) const;
-
  protected:
   Disassembler(const void* start, size_t length);
 
   bool Good();
   bool Bad(const char *reason);
 
   // Returns true if the array lies within our memory region.
   bool IsArrayInBounds(size_t offset, size_t elements, size_t element_size) {
     return offset <= length() && elements <= (length() - offset) / element_size;
   }
 
   // Reduce the length of the image in memory. Does not actually free
-  // (or realloc) any memory. Usually only called via ParseHeader()
+  // (or realloc) any memory. Usually only called via ParseHeader().
   void ReduceLength(size_t reduced_length);
 
  private:
   const char* failure_reason_;
 
   //
-  // Basic information that is always valid after Construction, though
-  // ParseHeader may shorten the length if the executable is shorter than
-  // the total data.
+  // Basic information that is always valid after construction, although
+  // ParseHeader() may shorten |length_| if the executable is shorter than the
+  // total data.
   //
   size_t length_;         // In current memory.
   const uint8_t* start_;  // In current memory, base for 'file offsets'.
   const uint8_t* end_;    // In current memory.
 
   DISALLOW_COPY_AND_ASSIGN(Disassembler);
 };
 
 }  // namespace courgette
 
 #endif  // COURGETTE_DISASSEMBLER_H_