[Python-checkins] r86587 - in python/branches/py3k: Lib/test/test_memoryio.py Misc/NEWS Modules/_io/bytesio.c

[benjamin.peterson]

Author: benjamin.peterson
Date: Sat Nov 20 18:24:04 2010
New Revision: 86587

Log:
correct logic when pos is after the string #10467

Modified:
   python/branches/py3k/Lib/test/test_memoryio.py
   python/branches/py3k/Misc/NEWS
   python/branches/py3k/Modules/_io/bytesio.c

Modified: python/branches/py3k/Lib/test/test_memoryio.py
==============================================================================
--- python/branches/py3k/Lib/test/test_memoryio.py	(original)
+++ python/branches/py3k/Lib/test/test_memoryio.py	Sat Nov 20 18:24:04 2010
@@ -452,6 +452,11 @@
         self.assertEqual(a.tobytes(), b"1234567890d")
         memio.close()
         self.assertRaises(ValueError, memio.readinto, b)
+        memio = self.ioclass(b"123")
+        b = bytearray()
+        memio.seek(42)
+        memio.readinto(b)
+        self.assertEqual(b, b"")
 
     def test_relative_seek(self):
         buf = self.buftype("1234567890")

Modified: python/branches/py3k/Misc/NEWS
==============================================================================
--- python/branches/py3k/Misc/NEWS	(original)
+++ python/branches/py3k/Misc/NEWS	Sat Nov 20 18:24:04 2010
@@ -24,6 +24,9 @@
 Library
 -------
 
+- Issue #10467: Fix BytesIO.readinto() after seeking into a position after the
+  end of the file.
+
 - Issue #1682942: configparser supports alternative option/value delimiters.
 
 - Issue #5412: configparser supports mapping protocol access.

Modified: python/branches/py3k/Modules/_io/bytesio.c
==============================================================================
--- python/branches/py3k/Modules/_io/bytesio.c	(original)
+++ python/branches/py3k/Modules/_io/bytesio.c	Sat Nov 20 18:24:04 2010
@@ -430,15 +430,20 @@
 bytesio_readinto(bytesio *self, PyObject *buffer)
 {
     void *raw_buffer;
-    Py_ssize_t len;
+    Py_ssize_t len, n;
 
     CHECK_CLOSED(self);
 
     if (PyObject_AsWriteBuffer(buffer, &raw_buffer, &len) == -1)
         return NULL;
 
-    if (self->pos + len > self->string_size)
-        len = self->string_size - self->pos;
+    /* adjust invalid sizes */
+    n = self->string_size - self->pos;
+    if (len > n) {
+        len = n;
+        if (len < 0)
+            len = 0;
+    }
 
     memcpy(raw_buffer, self->buf + self->pos, len);
     assert(self->pos + len < PY_SSIZE_T_MAX);