[pypy-commit] pypy faster-rstruct-2: WIP: add a failing test which show why the current way to detect alignement is buggy

[antocuni]

Author: Antonio Cuni <anto.cuni at gmail.com>
Branch: faster-rstruct-2
Changeset: r91334:6bed52a9d7c6
Date: 2017-05-18 16:26 +0200
http://bitbucket.org/pypy/pypy/changeset/6bed52a9d7c6/

Log:	WIP: add a failing test which show why the current way to detect
	alignement is buggy

diff --git a/rpython/rlib/rstruct/test/test_pack.py b/rpython/rlib/rstruct/test/test_pack.py
--- a/rpython/rlib/rstruct/test/test_pack.py
+++ b/rpython/rlib/rstruct/test/test_pack.py
@@ -2,6 +2,7 @@
 from rpython.rlib.rarithmetic import r_ulonglong
 from rpython.rlib.rstruct import standardfmttable, nativefmttable
 from rpython.rlib.rstruct.error import StructOverflowError
+from rpython.rlib.buffer import SubBuffer
 from rpython.rlib.mutbuffer import MutableStringBuffer
 import struct
 
@@ -215,3 +216,17 @@
         assert fake_fmtiter.pos == wbuf.getlength()
         got = wbuf.finish()
         assert got == expected
+
+    def test_subbuffer(self):
+        # to force a non-aligned 'i'
+        expected = struct.pack('=BBi', 0xAB, 0xCD, 0x1234)
+        size = len(expected)
+        #
+        wbuf = MutableStringBuffer(size)
+        wsubbuf = SubBuffer(wbuf, 2, size-4)
+        wbuf.setitem(0, chr(0xAB))
+        wbuf.setitem(1, chr(0xCD))
+        fake_fmtiter = self.mypack_into('i', wsubbuf, 0x1234)
+        assert fake_fmtiter.pos == wbuf.getlength()
+        got = wbuf.finish()
+        assert got == expected