Currency work.

src/Currency.cpp

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+
+#include "Currency.h"
+
+#include <cmath>
+#include <stdexcept>
+
+uint160 Currency::sNatMask("FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF0000");
+uint160 Currency::sNatZero("FFFFFFFFFFFFFFFFFFFFFFFFFFFF000000000000");
+uint64 Amount::sMaxCanon(1ull << 63);
+
+Currency::Currency(const uint160& v) : mValue(v)
+{
+	if (!v) mType = ctNATIVE;
+	if (!(v & sNatZero)) mType = ctNATIONAL;
+	mType = ctNATIONAL;
+}
+
+bool Currency::isCommensurate(const Currency& c) const
+{
+	if (isNative())
+		return c.isNative();
+	if (isCustom())
+		return mValue == c.mValue;
+	if (!c.isNational()) return false;
+	return (mValue & sNatMask) == (c.mValue & sNatMask);
+}
+
+unsigned char Currency::getScale() const
+{
+	return *(mValue.begin());
+}
+
+void Currency::setScale(unsigned char s)
+{
+	*(mValue.begin()) = s;
+}
+
+void Amount::canonicalize()
+{ // clear high bit to avoid overflows
+	if(mQuantity > sMaxCanon)
+	{
+		if (!mCurrency.isNational()) throw std::runtime_error("Currency overflow");
+		unsigned char s = mCurrency.getScale();
+		if (s==255) throw std::runtime_error("Currency overflow");
+		mCurrency.setScale(s + 1);
+		mQuantity /= 10.0;
+	}
+}
+
+double Amount::getDisplayQuantity() const
+{
+	if(!mCurrency.isNational()) throw std::runtime_error("Can only scale national currencies");
+	int scale=mCurrency.getScale();
+	return static_cast<double>(mQuantity) * pow(10, 128-scale);
+}
+