ENH: Make layout order an initialization parameter of ArrayProxy

Author: effigies

nibabel/arrayproxy.py

@@ -53,7 +53,7 @@
 KEEP_FILE_OPEN_DEFAULT = False
 
 
-class ArrayProxy(object):
+class ArrayProxy:
     """ Class to act as proxy for the array that can be read from a file
 
     The array proxy allows us to freeze the passed fileobj and header such that
@@ -83,10 +83,9 @@ class ArrayProxy(object):
     See :mod:`nibabel.minc1`, :mod:`nibabel.ecat` and :mod:`nibabel.parrec` for
     examples.
     """
-    # Assume Fortran array memory layout
     order = 'F'
 
-    def __init__(self, file_like, spec, *, mmap=True, keep_file_open=None):
+    def __init__(self, file_like, spec, *, mmap=True, order=None, keep_file_open=None):
         """Initialize array proxy instance
 
         Parameters
@@ -116,6 +115,10 @@ def __init__(self, file_like, spec, *, mmap=True, keep_file_open=None):
             True gives the same behavior as ``mmap='c'``.  If `file_like`
             cannot be memory-mapped, ignore `mmap` value and read array from
             file.
+        order : {'F', 'C'}, optional, keyword only
+            `order` controls the order of the data array layout. Fortran-style,
+            column-major order may be indicated with 'F', and C-style, row-major
+            order may be indicated with 'C'. The default order is 'F'.
         keep_file_open : { None, True, False }, optional, keyword only
             `keep_file_open` controls whether a new file handle is created
             every time the image is accessed, or a single file handle is
@@ -128,6 +131,8 @@ def __init__(self, file_like, spec, *, mmap=True, keep_file_open=None):
         """
         if mmap not in (True, False, 'c', 'r'):
             raise ValueError("mmap should be one of {True, False, 'c', 'r'}")
+        if order not in (None, 'C', 'F'):
+            raise ValueError("order should be one of {'C', 'F'}")
         self.file_like = file_like
         if hasattr(spec, 'get_data_shape'):
             slope, inter = spec.get_slope_inter()
@@ -147,6 +152,8 @@ def __init__(self, file_like, spec, *, mmap=True, keep_file_open=None):
         # Permit any specifier that can be interpreted as a numpy dtype
         self._dtype = np.dtype(self._dtype)
         self._mmap = mmap
+        if order is not None:
+            self.order = order
         # Flags to keep track of whether a single ImageOpener is created, and
         # whether a single underlying file handle is created.
         self._keep_file_open, self._persist_opener = \