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

class Delta {
public:
  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:
	cerr << "decode: " << done;
	abort();
      }
    }
  }

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

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

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

// Note: This does not benefit from -Wformat= checking, due to the
// enclosing template. Further, it was not used.
// void 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 %" W "u\n", winst.position, winst.size);
// 	break;
//       case XD3_ADD: 
// 	DP(RINT "%" Q "u add %" W "u\n", winst.position, winst.size);
// 	break;
//       default:
// 	DP(RINT "%" Q "u copy %" W "u @ %" Q "u (mode %u)\n", 
// 	   winst.position, winst.size, winst.addr, winst.mode);
// 	break;
//       }
//     }
//   }

private:
  xd3_stream stream_;
};