On 3.3.2014. 2:27, Ian Kelly wrote:
Python 3.3 has a C API function to create a memoryview for a char*,
that can be made read-only.
http://docs.python.org/3/c-api/memoryview.html#PyMemoryView_FromMemory
I don't see a way to do what you want in pure Python, apart from
perhaps writing an elaborate proxy class that would just be a poor
man's memoryview. Or you could bite the bullet and copy everything
once at the start to create a bytes object, and then never have to
worry about it again.
Just for reference, it is doable in pure Python, with ctypes help:
pydll = ctypes.cdll.LoadLibrary("python{}{}".format(
sys.version_info.major, sys.version_info.minor))
def ro_memoryview_from_bytearray(buffer):
assert isinstance(buffer, bytearray)
ptr = ctypes.c_char_p(pydll.PyByteArray_AsString(
ctypes.py_object(buffer)))
mv_id = pydll.PyMemoryView_FromMemory(ptr, len(buffer), 0)
return ctypes.cast(mv_id, py_object).value
Note that this is just the jist, in real code I added safeguards to
prevent misuse of the (temporary) memoryview.
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