/**
 * PANDA 3D SOFTWARE
 * Copyright (c) Carnegie Mellon University.  All rights reserved.
 *
 * All use of this software is subject to the terms of the revised BSD
 * license.  You should have received a copy of this license along
 * with this source code in a file named "LICENSE."
 *
 * @file p3dPatchfileReader.h
 * @author drose
 * @date 2009-09-27
 */

#ifndef P3DPATCHFILEREADER_H
#define P3DPATCHFILEREADER_H

#include "p3d_plugin_common.h"
#include "p3dInstanceManager.h"  // for openssl
#include "fileSpec.h"

/**
 * A read-only implementation of Panda's patchfile format, for applying
 * patches.
 *
 * This object assumes that the sourcefile has been already validated against
 * its md5 hash, and does not validate it again.  It *does* verify that the
 * md5 hash in source and target match those read in the patchfile header; and
 * it verifies the md5 hash on the target after completion.
 */
class P3DPatchfileReader {
public:
  P3DPatchfileReader(const std::string &package_dir,
                     const FileSpec &patchfile,
                     const FileSpec &source,
                     const FileSpec &target);
  ~P3DPatchfileReader();

  bool open_read();
  inline bool is_open() const;

  bool step();
  inline size_t get_bytes_written() const;
  inline bool get_success() const;

  void close();

private:
  bool copy_bytes(std::istream &in, size_t copy_byte_count);
  inline unsigned int read_uint16();
  inline unsigned int read_uint32();
  inline int read_int32();

private:
  std::string _package_dir;
  FileSpec _patchfile;
  FileSpec _source;
  FileSpec _target;

  std::string _output_pathname;
  ifstream _patch_in;
  ifstream _source_in;
  ofstream _target_out;

  bool _is_open;
  size_t _target_length;
  size_t _bytes_written;
  bool _success;
};

#include "p3dPatchfileReader.I"

#endif