add long-time overdue convenience function

2 files changed, 23 insertions, 0 deletions

diff --git a/src/include/taler_amount_lib.h b/src/include/taler_amount_lib.h
index a1f6c7d35..c1f42e473 100644
--- a/src/include/taler_amount_lib.h
+++ b/src/include/taler_amount_lib.h
@@ -161,6 +161,17 @@ TALER_amount_set_zero (const char *cur,
 
 
 /**
+ * Test if the given @a amount is zero.
+ *
+ * @param amount amount to compare to zero
+ * @return true if the amount is zero,
+ *         false if it is non-zero or invalid
+ */
+bool
+TALER_amount_is_zero (const struct TALER_Amount *amount);
+
+
+/**
  * Test if the given amount is valid.
  *
  * @param amount amount to check
diff --git a/src/util/amount.c b/src/util/amount.c
index 01f2a2313..ae9ae652e 100644
--- a/src/util/amount.c
+++ b/src/util/amount.c
@@ -241,6 +241,18 @@ TALER_amount_is_valid (const struct TALER_Amount *amount)
 }
 
 
+bool
+TALER_amount_is_zero (const struct TALER_Amount *amount)
+{
+  if (GNUNET_OK !=
+      TALER_amount_is_valid (amount))
+    return false;
+  return
+    (0 == amount->value) &&
+    (0 == amount->fraction);
+}
+
+
 /**
  * Test if @a a is valid, NBO variant.
  *