ledger/amount.h

#ifndef _AMOUNT_H
#define _AMOUNT_H

#include <map>
#include <string>
#include <ctime>
#include <iostream>
#include <sstream>

namespace ledger {

class commodity_t;

class amount_t
{
  typedef void * base_type;

  void _init();
  void _copy(const amount_t& amt);
  void _clear();

 public:
  base_type	quantity;	// amount, to MAX_PRECISION
  commodity_t *	commodity;

  bool valid() const {
    if (quantity)
      return commodity != NULL;
    else
      return commodity == NULL;
  }

  // constructors
  amount_t(commodity_t * _commodity = NULL)
    : quantity(NULL), commodity(_commodity) {}

  amount_t(const amount_t& amt) : quantity(NULL) {
    if (amt.quantity)
      _copy(amt);
    else
      commodity = amt.commodity;
  }
  amount_t(const std::string& value) {
    _init();
    std::istringstream str(value);
    str >> *this;
  }
  amount_t(const char * value) {
    _init();
    std::string valstr(value);
    std::istringstream str(valstr);
    str >> *this;
  }
  amount_t(const bool value);
  amount_t(const int value);
  amount_t(const unsigned int value);
  amount_t(const double value);

  // destructor
  ~amount_t() {
    if (quantity)
      _clear();
  }

  // assignment operator
  amount_t& operator=(const amount_t& amt);
  amount_t& operator=(const std::string& value);
  amount_t& operator=(const char * value);
  amount_t& operator=(const bool value);
  amount_t& operator=(const int value);
  amount_t& operator=(const unsigned int value);
  amount_t& operator=(const double value);

  // general methods
  amount_t round(int precision = -1) const;

  // in-place arithmetic
  amount_t& operator*=(const amount_t& amt);
  amount_t& operator/=(const amount_t& amt);
  amount_t& operator%=(const amount_t& amt);
  amount_t& operator+=(const amount_t& amt);
  amount_t& operator-=(const amount_t& amt);

  // simple arithmetic
  amount_t operator*(const amount_t& amt) const {
    amount_t temp = *this;
    temp *= amt;
    return temp;
  }
  amount_t operator/(const amount_t& amt) const {
    amount_t temp = *this;
    temp /= amt;
    return temp;
  }
  amount_t operator%(const amount_t& amt) const {
    amount_t temp = *this;
    temp %= amt;
    return temp;
  }
  amount_t operator+(const amount_t& amt) const {
    amount_t temp = *this;
    temp += amt;
    return temp;
  }
  amount_t operator-(const amount_t& amt) const {
    amount_t temp = *this;
    temp -= amt;
    return temp;
  }

  // unary negation
  amount_t& negate();
  amount_t negated() const {
    amount_t temp = *this;
    temp.negate();
    return temp;
  }
  amount_t operator-() const {
    return negated();
  }

  // test for non-zero (use ! for zero)
  operator bool() const;

  // comparisons to zero
  bool operator<(const int num) const;
  bool operator<=(const int num) const;
  bool operator>(const int num) const;
  bool operator>=(const int num) const;

  // comparisons between amounts
  bool operator<(const amount_t& amt) const;
  bool operator<=(const amount_t& amt) const;
  bool operator>(const amount_t& amt) const;
  bool operator>=(const amount_t& amt) const;
  bool operator==(const amount_t& amt) const;
  bool operator!=(const amount_t& amt) const {
    if (commodity != amt.commodity)
      return true;
    return ! (*this == amt);
  }

  amount_t value(const std::time_t moment) const;

  operator std::string() const;

  void parse(std::istream& in);
  void parse(const std::string& str) {
    std::istringstream stream(str);
    parse(stream);
  }

  void write_quantity(std::ostream& out) const;
  void read_quantity(std::istream& in);

  friend std::istream& operator>>(std::istream& in, amount_t& amt);
};

void parse_quantity(std::istream& in, std::string& value);
void parse_commodity(std::istream& in, std::string& symbol);

inline amount_t abs(const amount_t& amt) {
  return amt < 0 ? amt.negated() : amt;
}

inline std::istream& operator>>(std::istream& in, amount_t& amt) {
  amt.parse(in);
  return in;
}

std::ostream& operator<<(std::ostream& out, const amount_t& amt);


#define COMMODITY_STYLE_DEFAULTS   0x00
#define COMMODITY_STYLE_SUFFIXED   0x01
#define COMMODITY_STYLE_SEPARATED  0x02
#define COMMODITY_STYLE_EUROPEAN   0x04
#define COMMODITY_STYLE_THOUSANDS  0x08
#define COMMODITY_STYLE_CONSULTED  0x10
#define COMMODITY_STYLE_NOMARKET   0x20

typedef std::map<const std::time_t, amount_t>  history_map;
typedef std::pair<const std::time_t, amount_t> history_pair;

typedef std::map<const std::string, commodity_t *>  commodities_map;
typedef std::pair<const std::string, commodity_t *> commodities_pair;

class commodity_t
{
 public:
  typedef unsigned short ident_t;

  std::string	symbol;
  std::string	name;
  std::string	note;
  unsigned int	precision;
  unsigned int	flags;
  history_map	history;
  amount_t	conversion;
  ident_t	ident;

  // If set, this global function pointer is called to determine
  // whether prices have been updated in the meanwhile.

  static void (*updater)(commodity_t *	   commodity,
			 const std::time_t date,
			 const amount_t&   price,
			 const std::time_t moment);

  // This map remembers all commodities that have been
  // defined thus far.

  static commodities_map commodities;
  static commodity_t *   null_commodity;

  static void add_commodity(commodity_t * commodity,
			    const std::string symbol = "") {
    commodities.insert(commodities_pair((symbol.empty() ?
					 commodity->symbol : symbol),
					commodity));
  }
  static bool remove_commodity(commodity_t * commodity) {
    commodities_map::size_type n = commodities.erase(commodity->symbol);
    return n > 0;
  }
  static commodity_t * find_commodity(const std::string& symbol,
				      bool auto_create = false);

  // Now the per-object constructor and methods

  commodity_t(const std::string& _symbol    = "",
	      unsigned int	 _precision = 2,
	      unsigned int       _flags	    = COMMODITY_STYLE_DEFAULTS)
    : symbol(_symbol), precision(_precision), flags(_flags) {}

  void add_price(const std::time_t date, const amount_t& price) {
    history.insert(history_pair(date, price));
  }
  bool remove_price(const std::time_t date) {
    history_map::size_type n = history.erase(date);
    return n > 0;
  }

  void set_conversion(const amount_t& price) {
    conversion = price;
  }

  amount_t value(const std::time_t moment = std::time(NULL));
};

} // namespace ledger

#endif // _AMOUNT_H