Bug #16441: avoid excessive memory usage working with large gzip files

Lib/gzip.py

@@ -421,7 +421,7 @@ class GzipFile(io.BufferedIOBase):
             if offset < self.offset:
                 raise IOError('Negative seek in write mode')
             count = offset - self.offset
-            for i in range(count // 1024):
+            for i in xrange(count // 1024):
                 self.write(1024 * '\0')
             self.write((count % 1024) * '\0')
         elif self.mode == READ:
@@ -429,7 +429,7 @@ class GzipFile(io.BufferedIOBase):
                 # for negative seek, rewind and do positive seek
                 self.rewind()
             count = offset - self.offset
-            for i in range(count // 1024):
+            for i in xrange(count // 1024):
                 self.read(1024)
             self.read(count % 1024)
 

Misc/NEWS

@@ -464,6 +464,9 @@ Library
 - Issue #6884: Fix long-standing bugs with MANIFEST.in parsing in distutils
   on Windows.
 
+- Issue #16441: Avoid excessive memory usage working with large gzip
+  files using the gzip module.
+
 Extension Modules
 -----------------