add a validate method to HashedStream

1 files changed, 10 insertions, 0 deletions

diff --git a/dedup/hashing.py b/dedup/hashing.py
index 1419811..2a83929 100644
--- a/dedup/hashing.py
+++ b/dedup/hashing.py
@@ -183,3 +183,13 @@ class HashedStream(object):
 
     def hexdigest(self):
         return self.hashobj.hexdigest()
+
+    def validate(self, hexdigest):
+        """Soak up any remaining input and validate the read data using the
+        given hexdigest.
+        @raises ValueError: when the hash does not match
+        """
+        while self.read(65536):
+            pass
+        if self.hexdigest() != hexdigest:
+            raise ValueError("hash sum mismatch")