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Diffstat (limited to 'external_libs/python/pyzmq-14.7.0/zmq/backend/cython/rebuffer.pyx')
| -rw-r--r-- | external_libs/python/pyzmq-14.7.0/zmq/backend/cython/rebuffer.pyx | 104 |
1 files changed, 104 insertions, 0 deletions
diff --git a/external_libs/python/pyzmq-14.7.0/zmq/backend/cython/rebuffer.pyx b/external_libs/python/pyzmq-14.7.0/zmq/backend/cython/rebuffer.pyx new file mode 100644 index 00000000..402e3b6e --- /dev/null +++ b/external_libs/python/pyzmq-14.7.0/zmq/backend/cython/rebuffer.pyx @@ -0,0 +1,104 @@ +""" +Utility for changing itemsize of memoryviews, and getting +numpy arrays from byte-arrays that should be interpreted with a different +itemsize. + +Authors +------- +* MinRK +""" + +#----------------------------------------------------------------------------- +# Copyright (c) 2010-2012 Brian Granger, Min Ragan-Kelley +# +# This file is part of pyzmq +# +# Distributed under the terms of the New BSD License. The full license is in +# the file COPYING.BSD, distributed as part of this software. +#----------------------------------------------------------------------------- + +from libc.stdlib cimport malloc +from buffers cimport * + +cdef inline object _rebuffer(object obj, char * format, int itemsize): + """clobber the format & itemsize of a 1-D + + This is the Python 3 model, but will work on Python >= 2.6. Currently, + we use it only on >= 3.0. + """ + cdef Py_buffer view + cdef int flags = PyBUF_SIMPLE + cdef int mode = 0 + # cdef Py_ssize_t *shape, *strides, *suboffsets + + mode = check_buffer(obj) + if mode == 0: + raise TypeError("%r does not provide a buffer interface."%obj) + + if mode == 3: + flags = PyBUF_ANY_CONTIGUOUS + if format: + flags |= PyBUF_FORMAT + PyObject_GetBuffer(obj, &view, flags) + assert view.ndim <= 1, "Can only reinterpret 1-D memoryviews" + assert view.len % itemsize == 0, "Buffer of length %i not divisible into items of size %i"%(view.len, itemsize) + # hack the format + view.ndim = 1 + view.format = format + view.itemsize = itemsize + view.strides = <Py_ssize_t *>malloc(sizeof(Py_ssize_t)) + view.strides[0] = itemsize + view.shape = <Py_ssize_t *>malloc(sizeof(Py_ssize_t)) + view.shape[0] = view.len/itemsize + view.suboffsets = <Py_ssize_t *>malloc(sizeof(Py_ssize_t)) + view.suboffsets[0] = 0 + # for debug: make buffer writable, for zero-copy testing + # view.readonly = 0 + + return PyMemoryView_FromBuffer(&view) + else: + raise TypeError("This funciton is only for new-style buffer objects.") + +def rebuffer(obj, format, itemsize): + """Change the itemsize of a memoryview. + + Only for 1D contiguous buffers. + """ + return _rebuffer(obj, format, itemsize) + +def array_from_buffer(view, dtype, shape): + """Get a numpy array from a memoryview, regardless of the itemsize of the original + memoryview. This is important, because pyzmq does not send memoryview shape data + over the wire, so we need to change the memoryview itemsize before calling + asarray. + """ + import numpy + A = numpy.array([],dtype=dtype) + ref = viewfromobject(A,0) + fmt = ref.format.encode() + buf = viewfromobject(view, 0) + buf = _rebuffer(view, fmt, ref.itemsize) + return numpy.asarray(buf, dtype=dtype).reshape(shape) + +def print_view_info(obj): + """simple utility for printing info on a new-style buffer object""" + cdef Py_buffer view + cdef int flags = PyBUF_ANY_CONTIGUOUS|PyBUF_FORMAT + cdef int mode = 0 + + mode = check_buffer(obj) + if mode == 0: + raise TypeError("%r does not provide a buffer interface."%obj) + + if mode == 3: + PyObject_GetBuffer(obj, &view, flags) + print <size_t>view.buf, view.len, view.format, view.ndim, + if view.ndim: + if view.shape: + print view.shape[0], + if view.strides: + print view.strides[0], + if view.suboffsets: + print view.suboffsets[0], + print +
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