merchant-frontend-examples

commit e5abc1b45040ffb26408b439823a07a2217cee62
parent de86dc7d48959ac5f2f9eee2245df54ff8761333
Author: Marcello Stanisci <marcello.stanisci@inria.fr>
Date:   Mon, 20 Feb 2017 17:07:35 +0100

Amount subtraction.

Diffstat:
M
Python/pytaler/amounts.py
 | 
26
++++++++++++++++++++++++++

1 file changed, 26 insertions(+), 0 deletions(-)
diff --git a/Python/pytaler/amounts.py b/Python/pytaler/amounts.py
@@ -27,3 +27,29 @@ def amount_sum(a1, a2):
            "fraction": fractions % FRACTION,
            "currency": a1["currency"]}
     return ret
+
+# Computes a1 - a2
+def amount_sub(a1, a2):
+    assert(a1["currency"] == a2["currency"])
+
+    # Normalize
+    a1["value"] += int(a1["fraction"] / FRACTION)
+    a2["value"] += int(a2["fraction"] / FRACTION)
+    a1["fraction"] = a1["fraction"] % FRACTION
+    a2["fraction"] = a2["fraction"] % FRACTION
+
+    # Extra care for fraction
+    if a1["fraction"] < a2["fraction"]:
+        a1["fraction"] += FRACTION
+        a1["value"] -= 1
+        assert(a1["value"] >= 0)
+
+    # Sub
+    ret = amount_get_zero(a1["currency"])
+    ret["value"] = a1["value"] - a2["value"]
+    ret["fraction"] = a1["fraction"] - a2["fraction"]
+
+    assert(ret["value"] >= 0)
+    assert(ret["fraction"] >= 0)
+
+    return ret