From: Victor Stinner <victor.stinner@haypocalc.com>
Date: Tue, 11 Oct 2011 21:00:31 +0000 (+0200)
Subject: Fix FileIO.readall() (new_buffersize()) for large files
X-Git-Tag: v3.3.0a1~1214
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=c5af7730e34f15d917730c66076125d4e545f11a;p=python

Fix FileIO.readall() (new_buffersize()) for large files

Truncate the buffer size to PY_SSIZE_T_MAX.
---

diff --git a/Modules/_io/fileio.c b/Modules/_io/fileio.c
index dc5945504d..ba5e096029 100644
--- a/Modules/_io/fileio.c
+++ b/Modules/_io/fileio.c
@@ -564,7 +564,11 @@ new_buffersize(fileio *self, size_t currentsize
         */
         if (end >= SMALLCHUNK && end >= pos && pos >= 0) {
             /* Add 1 so if the file were to grow we'd notice. */
-            return currentsize + end - pos + 1;
+            Py_off_t bufsize = currentsize + end - pos + 1;
+            if (bufsize < PY_SSIZE_T_MAX)
+                return (size_t)bufsize;
+            else
+                return PY_SSIZE_T_MAX;
         }
     }
 #endif