Base structures for currencies.

src/Currency.h

@@ -0,0 +1,70 @@
+#ifndef __CURRENCY__
+#define __CURRENCY__
+
+#include <string>
+
+#include "uint256.h"
+
+enum CurrencyType
+{
+	ctNATIVE,	// Currency transaction fees are paid in
+	ctNATIONAL,	// State-issued or ISO-recognized currencies
+	ctCUSTOM,	// Custom currencies
+};
+
+class Currency
+{
+protected:
+	uint160 mValue;
+	CurrencyType mType;
+
+public:
+	Currency() : mType(ctNATIVE) { ; }
+	Currency(const uint160& v);
+	Currency(const std::string& iso, uint16 version, unsigned char scale);
+
+	bool isCommensurate(const Currency&) const;
+	bool isNational() const { return mType == ctNATIONAL; }
+	bool isNative() const { return mType == ctNATIVE; }
+	bool isCustom() const { return mType == ctCUSTOM; }
+
+	const uint160& getCurrency() { return mValue; }
+	unsigned char getScale() const;
+
+	// These are only valid for national currencies
+	std::string getISO() const;
+	uint16 getVersion() const;
+};
+
+class Amount
+{
+protected:
+	Currency mCurrency;
+	uint64 mQuantity;
+
+public:
+
+	Amount(const Currency& c, const uint64& q) : mCurrency(c), mQuantity(q) { ; }
+
+	const Currency& getCurrency() const { return mCurrency; }
+	uint64 getQuantity() const { return mQuantity; }
+	double getDisplayQuantity() const;
+
+	// These throw if the currencies are incommensurate
+	// They handle scaling and represent the result as accurately as possible
+	bool operator==(const Amount&) const;
+	bool operator!=(const Amount&) const;
+	bool operator>=(const Amount&) const;
+	bool operator<=(const Amount&) const;
+	bool operator>(const Amount&) const;
+	bool operator<(const Amount&) const;
+	Amount operator+(const Amount&) const;
+	Amount operator-(const Amount&) const;
+	Amount& operator+=(const Amount&);
+	Amount& operator-=(const Amount&);
+
+	// This is used to score offers and works with incommensurate currencies
+	friend void divide(const Amount& offering, const Amount& taking, uint16& exponent, uint64& mantissa);
+};
+
+#endif