From 81749b0754f0799cb84beedd8b411544a2934c5f Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Tue, 30 Jul 1996 16:26:42 +0000
Subject: Added optional second arg to what(), giving the data read from the
 file (then f may be None).

---
 Lib/imghdr.py | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/Lib/imghdr.py b/Lib/imghdr.py
index 62518b5..10cc085 100644
--- a/Lib/imghdr.py
+++ b/Lib/imghdr.py
@@ -5,13 +5,19 @@
 # Recognize sound headers #
 #-------------------------#
 
-def what(filename):
-	f = open(filename, 'r')
-	h = f.read(32)
-	for tf in tests:
-		res = tf(h, f)
-		if res:
-			return res
+def what(filename, h=None):
+	if not h:
+		f = open(filename, 'r')
+		h = f.read(32)
+	else:
+		f = None
+	try:
+		for tf in tests:
+			res = tf(h, f)
+			if res:
+				return res
+	finally:
+		if f: f.close()
 	return None
 
 
-- 
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