[GNUnet-SVN] [taler-merchant-frontend-examples] 02/03: Amount subtraction.

[gnunet]

This is an automated email from the git hooks/post-receive script.

marcello pushed a commit to branch master
in repository merchant-frontend-examples.

commit e5abc1b45040ffb26408b439823a07a2217cee62
Author: Marcello Stanisci <address@hidden>
AuthorDate: Mon Feb 20 17:07:35 2017 +0100

    Amount subtraction.
---
 Python/pytaler/amounts.py | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/Python/pytaler/amounts.py b/Python/pytaler/amounts.py
index 9c5e83c..d39663f 100644
--- 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

-- 
To stop receiving notification emails like this one, please contact
address@hidden