From 8324a9a3e08413423c8ade7fb02db7ace0637c43 Mon Sep 17 00:00:00 2001
From: Sandro Mani <manisandro@gmail.com>
Date: Sun, 26 Jan 2014 00:11:15 +0100
Subject: [PATCH] Fix issue 447: Apparently some drivers only emit
 SANE_STATUS_EOF once, and SANE_STATUS_IO_ERROR after that. The code however
 assumed that the driver keeps emitting SANE_STATUS_EOF. This commit fixes
 this.

---
 Sane/_sane.c | 22 ++++++++++++++--------
 1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/Sane/_sane.c b/Sane/_sane.c
index 1c62610be..2ebcb1834 100644
--- a/Sane/_sane.c
+++ b/Sane/_sane.c
@@ -916,10 +916,13 @@ SaneDev_snap(SaneDevObject *self, PyObject *args)
                  call which returns SANE_STATUS_EOF in order to start
                  a new frame.
               */
-              do {
-                   st = sane_read(self->h, buffer, READSIZE, &len);
-                 }
-              while (st == SANE_STATUS_GOOD);
+              if (st != SANE_STATUS_EOF)
+                {
+                  do {
+                    st = sane_read(self->h, buffer, READSIZE, &len);
+                  }
+                  while (st == SANE_STATUS_GOOD);
+                }
               if (st != SANE_STATUS_EOF)
                 {
                    Py_BLOCK_THREADS
@@ -937,10 +940,13 @@ SaneDev_snap(SaneDevObject *self, PyObject *args)
         }
     }
   /* enforce SANE_STATUS_EOF. Can be necessary for ADF scans for some backends */
-  do {
-       st = sane_read(self->h, buffer, READSIZE, &len);
-     }
-  while (st == SANE_STATUS_GOOD);
+  if (st != SANE_STATUS_EOF)
+    {
+      do {
+        st = sane_read(self->h, buffer, READSIZE, &len);
+      }
+      while (st == SANE_STATUS_GOOD);
+    }
   if (st != SANE_STATUS_EOF)
     {
       sane_cancel(self->h);