Support extraction of GZIP files with the Python gzip module.

doc/changelog.txt

@@ -11,7 +11,8 @@
 * Added support for the lbzip2 program handling BZIP2 archives.
 * Added support for the plzip program handling LZIP archives.
 * Prevent overwriting the same file with repack.
-* Support extraction of BZIP2 files with the Python bz2 module.
+* Support extraction of BZIP2 (.bz2) files with the Python bz2 module.
+* Support extraction of GZIP (.gz) files with the Python gzip module.
 
 
 0.15 "Contraband" (released 8.4.2012)

patoolib/__init__.py

@@ -117,6 +117,7 @@ ArchivePrograms = {
     },
     'gzip': {
         None: ('pigz', 'gzip', '7z', '7za'),
+        'extract': ('pygzip',),
     },
     'lzh': {
         None: ('lha',),

patoolib/programs/pygzip.py

@@ -0,0 +1,44 @@
+# -*- coding: utf-8 -*-
+# Copyright (C) 2012 Bastian Kleineidam
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+"""Archive commands for the gzip Python module."""
+from __future__ import absolute_import
+# now gzip refers to the Python standard module, not the local one
+import gzip
+from patoolib import util
+
+READ_SIZE_BYTES = 1024*1024
+
+def extract_gzip (archive, encoding, cmd, **kwargs):
+    """Extract a GZIP archive with the gzip Python module functionality."""
+    verbose = kwargs['verbose']
+    if verbose:
+        util.log_info('extracting %s...' % archive)
+    targetname = util.get_single_outfile(kwargs['outdir'], archive)
+    gzipfile = gzip.GzipFile(archive)
+    try:
+        targetfile = open(targetname, 'wb')
+        try:
+            data = gzipfile.read(READ_SIZE_BYTES)
+            while data:
+                targetfile.write(data)
+                data = gzipfile.read(READ_SIZE_BYTES)
+        finally:
+            targetfile.close()
+    finally:
+        gzipfile.close()
+    if verbose:
+        util.log_info('... extracted to %s' % targetname)
+    return None

tests/test_archives.py

@@ -153,6 +153,11 @@ class TestArchives (ArchiveTest):
         self.archive_commands('t.txt.gz', singlefile=True)
         self.archive_extract('t.Z')
 
+    def test_pygzip (self):
+        self.program = 'pygzip'
+        self.archive_extract('t.gz')
+        self.archive_extract('t.txt.gz')
+
     @needs_program('pigz')
     def test_pigz (self):
         self.program = 'pigz'