delta.h

Linux下一个可以比较二进制文件的工具xdelta3.0u的源码。

// Mode: -*- C++ -*-

namespace regtest {

class Delta {
public:
  Delta(const Block &block);

  ~Delta() {
    xd3_free_stream(&stream_);
  }

  xoff_t AddedBytes() const {
    return stream_.whole_target.addslen;
  }

  xoff_t Windows() const {
    return stream_.whole_target.wininfolen;
  }

  void Print() const;

private:
  xd3_stream stream_;
};

Delta::Delta(const Block &block) {
  int ret;
  xd3_config config;
  memset(&stream_, 0, sizeof (stream_));
  memset(&config, 0, sizeof (config));

  xd3_init_config(&config, XD3_SKIP_EMIT | XD3_ADLER32_NOVER);

  CHECK_EQ(0, xd3_config_stream (&stream_, &config));

  xd3_avail_input (&stream_, block.Data(), block.Size());

  bool done = false;
  while (!done) {
    ret = xd3_decode_input(&stream_);
    
    switch (ret) {
    case XD3_INPUT:
      done = true;
      break;
    case XD3_OUTPUT:
      CHECK_EQ(0, xd3_whole_append_window (&stream_));
      break;
    case XD3_GOTHEADER:
    case XD3_WINSTART:
    case XD3_WINFINISH:
      break;
    default:
      DP(RINT "error code %s\n", xd3_strerror (ret));
      abort();
    }
  }
}

void Delta::Print() const {
  for (size_t i = 0; i < stream_.whole_target.instlen; i++) {
    xd3_winst &winst = stream_.whole_target.inst[i];
    switch (winst.type) {
    case XD3_RUN: 
      DP(RINT "%"Q"u run %u\n", winst.position, winst.size);
      break;
    case XD3_ADD: 
      DP(RINT "%"Q"u add %u\n", winst.position, winst.size);
      break;
    default:
      DP(RINT "%"Q"u copy %u @ %"Q"u (mode %u)\n", 
	 winst.position, winst.size, winst.addr, winst.mode);
      break;
    }
  }
}

}  // namespace