#ifndef VALUEUNIT_H		// -*- c++ -*-
#define VALUEUNIT_H
///
// Copyright (C) 2002 - 2004, Fredrik Arnerup & Rasmus Kaj, See COPYING
///
#include "stringutil.h"
#include <string>

template<class Value>
class ValueUnit;
template<class Value>
std::istream& operator >> (std::istream& in, ValueUnit<Value>& vu);

template<class Value>
class ValueUnit {
public:
  ValueUnit() : value_(0) {}
  ValueUnit(const Value& value, const std::string& unit)
    : value_(value), unit_(unit) {}
  const Value& value() const { return value_; }
  const std::string& unit() const { return unit_; }
  
private:
  Value value_;
  std::string unit_;
  friend std::istream& operator >> <> (std::istream& in, ValueUnit<Value>& vu);
};

template <typename Tp>
class TypeInfo<ValueUnit<Tp> > {
public:
  static std::string name() {
    return TypeInfo<Tp>::name() + " with unit";
  }
};

template<class Value>
std::istream& operator >> (std::istream& in, ValueUnit<Value>& vu) {
  if(in >> vu.value_) {
    vu.unit_ = "";
    if(!in.eof()) {
      in >> vu.unit_;
    }
  }
  return in;
}

/**
 * Special case for float, since readig a float from "14em" barfs, guessing
 * that the 'e' is for an exponent.
 */
template<>
std::istream& operator >> (std::istream& in, ValueUnit<float>& vu) {
  in >> std::ws;
  std::string value;
  char ch;
  while(in.get(ch)) {
    if((ch >= '0' && ch <= '9') || ch == '.' || (ch == '-' && value.empty()))
      value += ch;
    else {
      in.putback(ch);
      break;
    }
  }
  try {
    vu.value_ = to<float>(value);
  } catch(...) {
    // Note: There is a message with the exception that might be usefull,
    // but we shouldn't let it hide a higher-level message.
    in.setstate(in.badbit);
    return in;
  }
  vu.unit_ = "";

  if(!in) {
    // We tried to read past eof.  Sorry.  Make sure the state is not bad, but
    // it should still be eof.
    in.clear();
    in.setstate(in.eofbit);
  } else if(!in.eof()) {
    in >> vu.unit_;
  }
  return in;
}

#endif