buffer.c: Fix buffer resizing logic.

diff --git a/buffer.c b/buffer.c
index 59a85bf..9b6e0ff 100644 (file)
--- a/buffer.c
+++ b/buffer.c
@@ -340,7 +340,7 @@ static void ensure(PyObject *me, size_t n)
   if (BLEFT(b) < n) {
     size_t nn = BSZ(b);
     octet *p;
-    size_t want = BLEFT(b) + n;
+    size_t want = BLEN(b) + n;
     while (nn < want) nn <<= 1;
     p = xrealloc(BBASE(b), nn, BSZ(b));
     BCUR(b) = p + BLEN(b);