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-rw-r--r--lib/python2.7/ctypes/_endian.py64
1 files changed, 64 insertions, 0 deletions
diff --git a/lib/python2.7/ctypes/_endian.py b/lib/python2.7/ctypes/_endian.py
new file mode 100644
index 0000000..f80e675
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+++ b/lib/python2.7/ctypes/_endian.py
@@ -0,0 +1,64 @@
+######################################################################
+# This file should be kept compatible with Python 2.3, see PEP 291. #
+######################################################################
+import sys
+from ctypes import *
+
+_array_type = type(Array)
+
+def _other_endian(typ):
+ """Return the type with the 'other' byte order. Simple types like
+ c_int and so on already have __ctype_be__ and __ctype_le__
+ attributes which contain the types, for more complicated types
+ arrays and structures are supported.
+ """
+ # check _OTHER_ENDIAN attribute (present if typ is primitive type)
+ if hasattr(typ, _OTHER_ENDIAN):
+ return getattr(typ, _OTHER_ENDIAN)
+ # if typ is array
+ if isinstance(typ, _array_type):
+ return _other_endian(typ._type_) * typ._length_
+ # if typ is structure
+ if issubclass(typ, Structure):
+ return typ
+ raise TypeError("This type does not support other endian: %s" % typ)
+
+class _swapped_meta(type(Structure)):
+ def __setattr__(self, attrname, value):
+ if attrname == "_fields_":
+ fields = []
+ for desc in value:
+ name = desc[0]
+ typ = desc[1]
+ rest = desc[2:]
+ fields.append((name, _other_endian(typ)) + rest)
+ value = fields
+ super(_swapped_meta, self).__setattr__(attrname, value)
+
+################################################################
+
+# Note: The Structure metaclass checks for the *presence* (not the
+# value!) of a _swapped_bytes_ attribute to determine the bit order in
+# structures containing bit fields.
+
+if sys.byteorder == "little":
+ _OTHER_ENDIAN = "__ctype_be__"
+
+ LittleEndianStructure = Structure
+
+ class BigEndianStructure(Structure):
+ """Structure with big endian byte order"""
+ __metaclass__ = _swapped_meta
+ _swappedbytes_ = None
+
+elif sys.byteorder == "big":
+ _OTHER_ENDIAN = "__ctype_le__"
+
+ BigEndianStructure = Structure
+ class LittleEndianStructure(Structure):
+ """Structure with little endian byte order"""
+ __metaclass__ = _swapped_meta
+ _swappedbytes_ = None
+
+else:
+ raise RuntimeError("Invalid byteorder")