From 9a15322878f8d73f8e6d1621cda6a959af54c914 Mon Sep 17 00:00:00 2001
From: Benjamin Gilbert <bgilbert@backtick.net>
Date: Thu, 21 Aug 2014 23:02:50 -0400
Subject: [PATCH] Autodetect NDPI in TIFF parser so we don't choke on SVS files

---
 anonymize-slide.py | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/anonymize-slide.py b/anonymize-slide.py
index 3c23b50..22f5e22 100755
--- a/anonymize-slide.py
+++ b/anonymize-slide.py
@@ -57,7 +57,7 @@ class UnrecognizedFile(Exception):
 
 
 class TiffFile(file):
-    def __init__(self, path, ndpi=False):
+    def __init__(self, path):
         file.__init__(self, path, 'r+b')
 
         # Check header, decide endianness
@@ -74,7 +74,7 @@ def __init__(self, path, ndpi=False):
         self._ndpi = False
         version = self.read_fmt('H')
         if version == 42:
-            self._ndpi = ndpi
+            pass
         elif version == 43:
             self._bigtiff = True
             magic2, reserved = self.read_fmt('HH')
@@ -93,6 +93,14 @@ def __init__(self, path, ndpi=False):
             self.seek(directory_offset)
             directory = TiffDirectory(self, len(self.directories),
                     in_pointer_offset)
+            if not self.directories and not self._bigtiff:
+                # Check for NDPI.  Because we don't know we have an NDPI file
+                # until after reading the first directory, we will choke if
+                # the first directory is beyond 4 GB.
+                if NDPI_MAGIC in directory.entries:
+                    if DEBUG:
+                        print 'Enabling NDPI mode.'
+                    self._ndpi = True
             self.directories.append(directory)
         if not self.directories:
             raise IOError('No directories')
@@ -246,7 +254,7 @@ def do_aperio_svs(filename):
 
 
 def do_hamamatsu_ndpi(filename):
-    with TiffFile(filename, ndpi=True) as fh:
+    with TiffFile(filename) as fh:
         # Check for NDPI file
         if NDPI_MAGIC not in fh.directories[0].entries:
             raise UnrecognizedFile
@@ -262,8 +270,8 @@ def do_hamamatsu_ndpi(filename):
 
 
 format_handlers = [
-    do_hamamatsu_ndpi,
     do_aperio_svs,
+    do_hamamatsu_ndpi,
 ]