RF: Fail quietly on too-short header blocks

Author: effigies

nibabel/analyze.py

@@ -895,8 +895,7 @@ def _chk_pixdims(hdr, fix=False):
     @classmethod
     def may_contain_header(klass, binaryblock):
         if len(binaryblock) < klass.sizeof_hdr:
-            raise ValueError('Must pass a binary block >= %d bytes' %
-                             klass.sizeof_hdr)
+            return False
 
         hdr_struct = np.ndarray(shape=(), dtype=header_dtype,
                                 buffer=binaryblock[:klass.sizeof_hdr])

nibabel/minc1.py

@@ -282,9 +282,6 @@ def data_from_fileobj(self, fileobj):
 class Minc1Header(MincHeader):
     @classmethod
     def may_contain_header(klass, binaryblock):
-        if len(binaryblock) < 4:
-            raise ValueError('Must pass a binary block >= 4 bytes')
-
         return binaryblock[:4] == b'CDF\x01'
 
 

nibabel/minc2.py

@@ -137,9 +137,6 @@ def get_scaled_data(self, sliceobj=()):
 class Minc2Header(MincHeader):
     @classmethod
     def may_contain_header(klass, binaryblock):
-        if len(binaryblock) < 4:
-            raise ValueError('Must pass a binary block >= 4 bytes')
-
         return binaryblock[:4] == b'\211HDF'
 
 

nibabel/nifti1.py

@@ -1614,8 +1614,7 @@ def _chk_xform_code(klass, code_type, hdr, fix):
     @classmethod
     def may_contain_header(klass, binaryblock):
         if len(binaryblock) < klass.sizeof_hdr:
-            raise ValueError('Must pass a binary block >= %d bytes' %
-                             klass.sizeof_hdr)
+            return False
 
         hdr_struct = np.ndarray(shape=(), dtype=header_dtype,
                                 buffer=binaryblock[:klass.sizeof_hdr])

nibabel/nifti2.py

@@ -224,8 +224,7 @@ def _chk_eol_check(hdr, fix=False):
     @classmethod
     def may_contain_header(klass, binaryblock):
         if len(binaryblock) < klass.sizeof_hdr:
-            raise ValueError('Must pass a binary block >= %d bytes' %
-                             klass.sizeof_hdr)
+            return False
 
         hdr_struct = np.ndarray(shape=(), dtype=header_dtype,
                                 buffer=binaryblock[:klass.sizeof_hdr])

nibabel/spm2analyze.py

@@ -116,8 +116,7 @@ def get_slope_inter(self):
     @classmethod
     def may_contain_header(klass, binaryblock):
         if len(binaryblock) < klass.sizeof_hdr:
-            raise ValueError('Must pass a binary block >= %d bytes' %
-                             klass.sizeof_hdr)
+            return False
 
         hdr_struct = np.ndarray(shape=(), dtype=header_dtype,
                                 buffer=binaryblock[:klass.sizeof_hdr])

nibabel/tests/test_image_types.py

@@ -21,7 +21,7 @@
                 Spm2AnalyzeImage, Spm99AnalyzeImage,
                 MGHImage, all_image_classes)
 
-from nose.tools import assert_true, assert_raises
+from nose.tools import assert_true
 
 DATA_PATH = pjoin(dirname(__file__), 'data')
 
@@ -46,17 +46,13 @@ def check_img(img_path, img_klass, sniff_mode, sniff, expect_success,
                       msg):
             """Embedded function to do the actual checks expected."""
 
-            if sniff_mode == 'empty' and \
-                    hasattr(img_klass.header_class, 'may_contain_header'):
-                assert_raises(ValueError,
-                              img_klass.header_class.may_contain_header, sniff)
-
             if sniff_mode == 'no_sniff':
                 # Don't pass any sniff--not even "None"
                 is_img, new_sniff = img_klass.path_maybe_image(img_path)
             elif sniff_mode in ('empty', 'irrelevant', 'bad_sniff'):
                 # Add img_path to binaryblock sniff parameters
-                is_img, new_sniff = img_klass.path_maybe_image(img_path, (sniff, img_path))
+                is_img, new_sniff = img_klass.path_maybe_image(
+                    img_path, (sniff, img_path))
             else:
                 # Pass a sniff, but don't reuse across images.
                 is_img, new_sniff = img_klass.path_maybe_image(img_path, sniff)
@@ -67,7 +63,8 @@ def check_img(img_path, img_klass, sniff_mode, sniff, expect_success,
                                                             msg)
                 expected_sizeof_hdr = getattr(img_klass.header_class,
                                               'sizeof_hdr', 0)
-                current_sizeof_hdr = 0 if new_sniff is None else len(new_sniff[0])
+                current_sizeof_hdr = 0 if new_sniff is None else \
+                    len(new_sniff[0])
                 assert_true(current_sizeof_hdr >= expected_sizeof_hdr, new_msg)
 
                 # Check that the image type was recognized.