Issue #14684: Add support for predefined compression dictionaries to the zlib module.
Original patch by Sam Rushing.
diff --git a/Lib/test/test_zlib.py b/Lib/test/test_zlib.py
index 3c982c6..904ac4d 100644
--- a/Lib/test/test_zlib.py
+++ b/Lib/test/test_zlib.py
@@ -425,6 +425,36 @@
dco = zlib.decompressobj()
self.assertEqual(dco.flush(), b"") # Returns nothing
+ def test_dictionary(self):
+ h = HAMLET_SCENE
+ # build a simulated dictionary out of the words in HAMLET
+ words = h.split()
+ random.shuffle(words)
+ zdict = b''.join(words)
+ # use it to compress HAMLET
+ co = zlib.compressobj(zdict=zdict)
+ cd = co.compress(h) + co.flush()
+ # verify that it will decompress with the dictionary
+ dco = zlib.decompressobj(zdict=zdict)
+ self.assertEqual(dco.decompress(cd) + dco.flush(), h)
+ # verify that it fails when not given the dictionary
+ dco = zlib.decompressobj()
+ self.assertRaises(zlib.error, dco.decompress, cd)
+
+ def test_dictionary_streaming(self):
+ # this is simulating the needs of SPDY to be able to reuse the same
+ # stream object (with its compression state) between sets of compressed
+ # headers.
+ co = zlib.compressobj(zdict=HAMLET_SCENE)
+ do = zlib.decompressobj(zdict=HAMLET_SCENE)
+ piece = HAMLET_SCENE[1000:1500]
+ d0 = co.compress(piece) + co.flush(zlib.Z_SYNC_FLUSH)
+ d1 = co.compress(piece[100:]) + co.flush(zlib.Z_SYNC_FLUSH)
+ d2 = co.compress(piece[:-100]) + co.flush(zlib.Z_SYNC_FLUSH)
+ self.assertEqual(do.decompress(d0), piece)
+ self.assertEqual(do.decompress(d1), piece[100:])
+ self.assertEqual(do.decompress(d2), piece[:-100])
+
def test_decompress_incomplete_stream(self):
# This is 'foo', deflated
x = b'x\x9cK\xcb\xcf\x07\x00\x02\x82\x01E'