Added some general currency utilities.

[fulbank.git] / fulbank / currency.py

diff --git a/fulbank/currency.py b/fulbank/currency.py
new file mode 100644 (file)
index 0000000..547acb9
--- /dev/null
+++ b/fulbank/currency.py
@@ -0,0 +1,145 @@
+class currency(object):
+    def __init__(self, symbol):
+        self.symbol = symbol
+
+    def sformat(self, amount):
+        return "%s %s" % (self.symbol, self.format(amount))
+
+    def __repr__(self):
+        return "#<currency %s>" % self.symbol
+
+    @property
+    def zero(self):
+        return value(0, self)
+
+    _known = {}
+    @classmethod
+    def define(cls, *args, **kwargs):
+        self = cls(*args, **kwargs)
+        cls._known[self.symbol] = self
+    @classmethod
+    def get(cls, symbol):
+        return cls._known[symbol]
+
+    def __reduce__(self):
+        return _currency_restore, (type(self), self.symbol,)
+def _currency_restore(cls, symbol):
+    return cls.get(symbol)
+
+class integral(currency):
+    def __init__(self, symbol):
+        super().__init__(symbol)
+
+    def format(self, amount):
+        return "%i" % amount
+
+    def parse(self, text):
+        return value(int(text), self)
+
+class decimal(currency):
+    def __init__(self, symbol, separator, thseparator, decimals=2):
+        super().__init__(symbol)
+        self.separator = separator
+        self.thseparator = thseparator
+        self.decimals = decimals
+
+    def format(self, amount):
+        if amount < 0:
+            return "-" + self.format(-amount)
+        bias = 10 ** self.decimals
+        ip = amount // bias
+        fp = amount - (ip * bias)
+        return "%i.%0*i" % (ip, self.decimals, fp)
+
+    def parse(self, text):
+        def parse2(text):
+            p = text.find(self.separator)
+            bias = 10 ** self.decimals
+            if p < 0:
+                text = text.replace(self.thseparator)
+                if not text.isdigit():
+                    raise ValueError(text)
+                return int(text) * bias
+            else:
+                if p != len(text) - 3:
+                    raise ValueError(text)
+                ip = text[:p].replace(self.thseparator, "")
+                fp = text[p + 1:]
+                if not (ip.isdigit() and fp.isdigit()):
+                    raise ValueError(text)
+                ip = int(ip)
+                fp = int(fp)
+                if fp >= bias:
+                    raise ValueError(text)
+                return (ip * bias) + fp
+        if text[0:1] == "-":
+            return value(-parse2(text[1:]), self)
+        else:
+            return value(parse2(text), self)
+
+decimal.define("SEK", ",", " ")
+decimal.define("USD", ".", ",")
+integral.define("JPY")
+
+class value(object):
+    __slots__ = ["amount", "currency"]
+    def __init__(self, amount, currency):
+        self.amount = int(amount)
+        self.currency = currency
+
+    def __repr__(self):
+        return "%s %s" % (self.currency.symbol, self.currency.format(self.amount))
+
+    def __add__(self, other):
+        if self.currency != other.currency:
+            raise ValueError("cannot add %s to %s" % (other.currency.symbol, self.currency.symbol))
+        return value(int(self.amount + other.amount), self.currency)
+    def __sub__(self, other):
+        if self.currency != other.currency:
+            raise ValueError("cannot subtract %s from %s" % (other.currency.symbol, self.currency.symbol))
+        return value(int(self.amount - other.amount), self.currency)
+    def __mul__(self, other):
+        return value(int(self.amount * other), self.currency)
+    def __truediv__(self, other):
+        if self.currency != other.currency:
+            raise ValueError("cannot divide %s with %s" % (self.currency.symbol, other.currency.symbol))
+        return self.amount / other.amount
+    def __floordiv__(self, other):
+        if self.currency != other.currency:
+            raise ValueError("cannot divide %s with %s" % (self.currency.symbol, other.currency.symbol))
+        return self.amount // other.amount
+    def __mod__(self, other):
+        if self.currency != other.currency:
+            raise ValueError("cannot divide %s with %s" % (self.currency.symbol, other.currency.symbol))
+        return value(int(self.amount % other.amount), self.currency)
+    def __divmod__(self, other):
+        if self.currency != other.currency:
+            raise ValueError("cannot divide %s with %s" % (self.currency.symbol, other.currency.symbol))
+        return (self.amount // other.amount, value(int(self.amount % other.amount), self.currency))
+    def __neg__(self):
+        return value(-self.amount, self.currency)
+
+    def __eq__(self, other):
+        if self.currency != other.currency:
+            raise ValueError("cannot compare %s with %s" % (self.currency.symbol, other.currency.symbol))
+        return self.amount == other.amount
+    def __ne__(self, other):
+        if self.currency != other.currency:
+            raise ValueError("cannot compare %s with %s" % (self.currency.symbol, other.currency.symbol))
+        return self.amount != other.amount
+    def __lt__(self, other):
+        if self.currency != other.currency:
+            raise ValueError("cannot compare %s with %s" % (self.currency.symbol, other.currency.symbol))
+        return self.amount < other.amount
+    def __le__(self, other):
+        if self.currency != other.currency:
+            raise ValueError("cannot compare %s with %s" % (self.currency.symbol, other.currency.symbol))
+        return self.amount <= other.amount
+    def __gt__(self, other):
+        if self.currency != other.currency:
+            raise ValueError("cannot compare %s with %s" % (self.currency.symbol, other.currency.symbol))
+        return self.amount > other.amount
+    def __ge__(self, other):
+        if self.currency != other.currency:
+            raise ValueError("cannot compare %s with %s" % (self.currency.symbol, other.currency.symbol))
+        return self.amount >= other.amount