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// macho_id.h: Functions to gather identifying information from a macho file
//
// Author: Dan Waylonis

#ifndef COMMON_MAC_MACHO_ID_H__
#define COMMON_MAC_MACHO_ID_H__

#include <limits.h>
#include <mach/machine.h>
#include <mach-o/loader.h>

#include "common/mac/macho_walker.h"
#include "common/md5.h"

namespace MacFileUtilities {

class MachoID {
 public:
  MachoID(const char *path);
  MachoID(const char *path, void *memory, size_t size);
  ~MachoID();

  // For the given |cpu_type| and |cpu_subtype|, return a UUID from the LC_UUID
  // command.
  // Return false if there isn't a LC_UUID command.
  bool UUIDCommand(cpu_type_t cpu_type,
                   cpu_subtype_t cpu_subtype,
                   unsigned char identifier[16]);

  // For the given |cpu_type| and |cpu_subtype|, return a UUID from the
  // LC_ID_DYLIB command.
  // Return false if there isn't a LC_ID_DYLIB command.
  bool IDCommand(cpu_type_t cpu_type,
                 cpu_subtype_t cpu_subtype,
                 unsigned char identifier[16]);

  // For the given |cpu_type| and |cpu_subtype|, return the Adler32 CRC for the
  // mach-o data segment(s).
  // Return 0 on error (e.g., if the file is not a mach-o file)
  uint32_t Adler32(cpu_type_t cpu_type,
                   cpu_subtype_t cpu_subtype);

  // For the given |cpu_type|, and |cpu_subtype| return the MD5 for the mach-o
  // data segment(s).
  // Return true on success, false otherwise
  bool MD5(cpu_type_t cpu_type,
           cpu_subtype_t cpu_subtype,
           unsigned char identifier[16]);

 private:
  // Signature of class member function to be called with data read from file
  typedef void (MachoID::*UpdateFunction)(unsigned char *bytes, size_t size);

  // Update the CRC value by examining |size| |bytes| and applying the algorithm
  // to each byte.
  void UpdateCRC(unsigned char *bytes, size_t size);

  // Update the MD5 value by examining |size| |bytes| and applying the algorithm
  // to each byte.
  void UpdateMD5(unsigned char *bytes, size_t size);

  // Bottleneck for update routines
  void Update(MachoWalker *walker, off_t offset, size_t size);

  // Factory for the MachoWalker
  bool WalkHeader(cpu_type_t cpu_type, cpu_subtype_t cpu_subtype,
                  MachoWalker::LoadCommandCallback callback, void *context);

  // The callback from the MachoWalker for CRC and MD5
  static bool WalkerCB(MachoWalker *walker, load_command *cmd, off_t offset,
                       bool swap, void *context);

  // The callback from the MachoWalker for LC_UUID
  static bool UUIDWalkerCB(MachoWalker *walker, load_command *cmd, off_t offset,
                           bool swap, void *context);

  // The callback from the MachoWalker for LC_ID_DYLIB
  static bool IDWalkerCB(MachoWalker *walker, load_command *cmd, off_t offset,
                         bool swap, void *context);

  // File path
  char path_[PATH_MAX];

  // Memory region to read from
  void *memory_;

  // Size of the memory region
  size_t memory_size_;

  // The current crc value
  uint32_t crc_;

  // The MD5 context
  google_breakpad::MD5Context md5_context_;

  // The current update to call from the Update callback
  UpdateFunction update_function_;
};

}  // namespace MacFileUtilities

#endif  // COMMON_MAC_MACHO_ID_H__