Index: Lib/gzip.py
===================================================================
--- Lib/gzip.py	(révision 85039)
+++ Lib/gzip.py	(copie de travail)
@@ -336,6 +336,26 @@
         self.offset += size
         return chunk
 
+    def peek(self, n):
+        if self.mode != READ:
+            import errno
+            raise IOError(errno.EBADF, "read() on write-only GzipFile object")
+
+        # Do not return ridiculously small buffers
+        if n < 100:
+            n = 100
+        if self.extrasize == 0:
+            if self.fileobj is None:
+                return b''
+            try:
+                self._read(max(self.max_read_chunk, n))
+            except EOFError:
+                pass
+        offset = self.offset - self.extrastart
+        remaining = self.extrasize
+        assert remaining == len(self.extrabuf) - offset
+        return self.extrabuf[offset:offset + n]
+
     def _unread(self, buf):
         self.extrasize = len(buf) + self.extrasize
         self.offset -= len(buf)