75 lines
2.4 KiB
Cython
75 lines
2.4 KiB
Cython
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from cpython.array cimport array, clone
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'''
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These functions below, take a data element; if the data implements the
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buffer interface, the data is returned unchanged, otherwise, a python
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array is created from the data and returned.
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in both cases, the second parameter is initialized with a pointer to the
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starting address of the returned buffer
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The return value is a tuple, of (original data, array), where in the first
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case, array is None.
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The method used below (a untyped python array + array.data.as_floats pointer)
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results in the fastest list to array creation and usage. Even malloc isn't
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faster. Note, using memoryview (which we avoided for this case) is relatively
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slow in cython.
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When the user passes in a memoryview type, we have no choice but to use the
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memoryview passed in, though.
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'''
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cdef inline _ensure_float_view(data, float **f):
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cdef array arr
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cdef list src
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cdef int i
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cdef float [::1] memview
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# do if/else instead of straight try/except because its faster for list
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if not isinstance(data, (tuple, list)):
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try:
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memview = data
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f[0] = &memview[0]
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return data, None
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except Exception as e:
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import traceback; traceback.print_exc()
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src = list(data)
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arr = clone(array('f'), len(src), False)
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f[0] = arr.data.as_floats
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for i in range(len(src)):
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f[0][i] = src[i]
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else:
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src = list(data)
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arr = clone(array('f'), len(src), False)
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f[0] = arr.data.as_floats
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for i in range(len(src)):
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f[0][i] = src[i]
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return src, arr
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cdef inline _ensure_ushort_view(data, unsigned short **f):
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cdef array arr
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cdef list src
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cdef int i
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cdef unsigned short [::1] memview
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# do if/else instead of straight try/except because its faster for list
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if not isinstance(data, (tuple, list)):
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try:
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memview = data
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f[0] = &memview[0]
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return data, None
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except:
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src = list(data)
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arr = clone(array('H'), len(src), False)
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f[0] = arr.data.as_ushorts
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for i in range(len(src)):
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f[0][i] = src[i]
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else:
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src = list(data)
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arr = clone(array('H'), len(src), False)
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f[0] = arr.data.as_ushorts
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for i in range(len(src)):
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f[0][i] = src[i]
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return src, arr
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