From e7f27481a895fb73408e523202345fcd9355b00c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C5=81ukasz=20Langa?= <lukasz@langa.pl>
Date: Sat, 11 Jun 2016 16:42:36 -0700
Subject: [PATCH] Issue #27194: superfluous truncate calls in tarfile.py slow
 down extraction

Patch by Jason Fried.
---
 Lib/tarfile.py | 4 ++--
 Misc/ACKS      | 1 +
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/Lib/tarfile.py b/Lib/tarfile.py
index 86e1cf9b89c..721f9d7f918 100755
--- a/Lib/tarfile.py
+++ b/Lib/tarfile.py
@@ -2150,10 +2150,10 @@ class TarFile(object):
                 for offset, size in tarinfo.sparse:
                     target.seek(offset)
                     copyfileobj(source, target, size, ReadError)
+                target.seek(tarinfo.size)
+                target.truncate()
             else:
                 copyfileobj(source, target, tarinfo.size, ReadError)
-            target.seek(tarinfo.size)
-            target.truncate()
 
     def makeunknown(self, tarinfo, targetpath):
         """Make a file from a TarInfo object with an unknown type
diff --git a/Misc/ACKS b/Misc/ACKS
index 001373b9406..be303e0e501 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -458,6 +458,7 @@ Stefan Franke
 Martin Franklin
 Kent Frazier
 Bruce Frederiksen
+Jason Fried
 Robin Friedrich
 Bradley Froehle
 Ivan Frohne