1 files changed, 62 insertions, 3 deletions

diff --git a/courgette/disassembler.h b/courgette/disassembler.h
index bef1a90..2b4714d 100644
--- a/courgette/disassembler.h
+++ b/courgette/disassembler.h
@@ -7,23 +7,82 @@
 
 #include "base/basictypes.h"
 
+#include "courgette/courgette.h"
+
 namespace courgette {
 
 class AssemblyProgram;
-class PEInfo;
+
+// A Relative Virtual Address is the address in the image file after it is
+// loaded into memory relative to the image load address.
+typedef uint32 RVA;
 
 class Disassembler {
  public:
-  virtual ~Disassembler() {}
+  virtual ~Disassembler();
+
+  virtual ExecutableType kind() { return UNKNOWN; }
+
+  // ok() may always be called but returns 'true' only after ParseHeader
+  // succeeds.
+  bool ok() const { return failure_reason_ == NULL; }
+
+  // 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.
+  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.
+  size_t length() const { return length_; }
+  const uint8* start() const { return start_; }
+  const uint8* 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* OffsetToPointer(size_t offset) const;
+
  protected:
-  Disassembler() {}
+  Disassembler(const void* start, size_t length);
+
+  bool Good();
+  bool Bad(const char *reason);
+
+  // These helper functions avoid the need for casts in the main code.
+  uint16 ReadU16(const uint8* address, size_t offset) {
+    return *reinterpret_cast<const uint16*>(address + offset);
+  }
+
+  uint32 ReadU32(const uint8* address, size_t offset) {
+    return *reinterpret_cast<const uint32*>(address + offset);
+  }
+
+  uint64 ReadU64(const uint8* address, size_t offset) {
+    return *reinterpret_cast<const uint64*>(address + offset);
+  }
+
+  static uint32 Read32LittleEndian(const void* address) {
+    return *reinterpret_cast<const uint32*>(address);
+  }
+
+  // Reduce the length of the image in memory. Does not actually free
+  // (or realloc) any memory. Unusally 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.
+  //
+  size_t length_;         // In current memory.
+  const uint8* start_;    // In current memory, base for 'file offsets'.
+  const uint8* end_;      // In current memory.
+
   DISALLOW_COPY_AND_ASSIGN(Disassembler);
 };