1 files changed, 60 insertions, 0 deletions
diff --git a/balance.cc b/balance.cc
index 6305eb95..604d9d82 100644
--- a/balance.cc
+++ b/balance.cc
@@ -85,4 +85,64 @@ void balance_t::write(std::ostream& out,
   }
 }
 
+balance_t& balance_t::operator*=(const balance_t& bal)
+{
+  if (! *this || ! bal) {
+    return (*this = 0L);
+  }
+  else if (amounts.size() == 1 && bal.amounts.size() == 1) {
+    return *this *= (*bal.amounts.begin()).second;
+  }
+  else {
+    std::string msg;
+    std::ostringstream errmsg(msg);
+    errmsg << "It makes no sense to multiply two balances: "
+	   << *this << " * " << bal;
+    throw amount_error(errmsg.str());
+  }
+}
+
+balance_t& balance_t::operator/=(const balance_t& bal)
+{
+  if (! *this) {
+    return (*this = 0L);
+  }
+  else if (! bal) {
+    std::string msg;
+    std::ostringstream errmsg(msg);
+    errmsg << "Attempt to divide by zero: " << *this << " / " << bal;
+    throw amount_error(errmsg.str());
+  }
+  else if (amounts.size() == 1 && bal.amounts.size() == 1) {
+    return *this /= (*bal.amounts.begin()).second;
+  }
+  else if (*this == bal) {
+    return (*this = 1L);
+  }
+  else {
+    std::string msg;
+    std::ostringstream errmsg(msg);
+    errmsg << "It makes no sense to divide two balances: "
+	   << *this << " / " << bal;
+    throw amount_error(errmsg.str());
+  }
+}
+
+balance_t::operator amount_t() const
+{
+  if (amounts.size() == 1) {
+    return (*amounts.begin()).second;
+  }
+  else if (amounts.size() == 0) {
+    return amount_t();
+  }
+  else {
+    std::string msg;
+    std::ostringstream errmsg(msg);
+    errmsg << "Cannot convert a balance with "
+	   << "multiple commodities to an amount: " << *this;
+    throw amount_error(errmsg.str());
+  }
+}
+
 } // namespace ledger