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111 lines
4.2 KiB
111 lines
4.2 KiB
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This file is part of Magnum. |
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Copyright © 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019 |
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Vladimír Vondruš <mosra@centrum.cz> |
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Permission is hereby granted, free of charge, to any person obtaining a |
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copy of this software and associated documentation files (the "Software"), |
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to deal in the Software without restriction, including without limitation |
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the rights to use, copy, modify, merge, publish, distribute, sublicense, |
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and/or sell copies of the Software, and to permit persons to whom the |
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Software is furnished to do so, subject to the following conditions: |
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The above copyright notice and this permission notice shall be included |
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in all copies or substantial portions of the Software. |
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL |
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THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING |
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FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER |
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DEALINGS IN THE SOFTWARE. |
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.. |
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.. doctest setup |
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>>> from corrade import containers |
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.. py:class:: corrade.containers.ArrayView |
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Provides one-dimensional tightly packed view on a memory range. Convertible |
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both from and to Python objects supporting the Buffer Protocol, with one |
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dimension and stride of :py:`1`. See `StridedArrayView1D` and others for |
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more generic views. `ArrayView` is immutable, see `MutableArrayView` for |
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the mutable alterantive. All slicing operations are supported, specifying a |
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non-trivial stride will return `StridedArrayView1D` instead of `ArrayView`. |
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Example usage: |
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.. code:: pycon |
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>>> a = b'hello' |
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>>> b = containers.ArrayView(a) |
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>>> b[2] |
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'l' |
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>>> bytes(b[1:4]) |
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b'ell' |
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`Memory ownership and reference counting`_ |
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========================================== |
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Unlike in C++, the view keeps a reference to the original memory owner |
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object, meaning that calling :py:`del` on the original object will *not* |
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invalidate the view. Slicing a view creates a new view referencing the same |
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original object, without any dependency on the previous view. That means a |
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long chained slicing operation will not cause increased memory usage. |
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.. code:: pycon |
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>>> b.owner is a |
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True |
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>>> b[1:4][:-1].owner is a |
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True |
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`Comparison to Python's memoryview`_ |
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==================================== |
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The `ArrayView` class is equivalent to one-dimensional `memoryview` with a |
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stride of :py:`1`. For multiple dimensions and non-trivial strides, |
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`StridedArrayView1D` and friends provide a superset of `memoryview` |
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features. |
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.. py:class:: corrade.containers.MutableArrayView |
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Equivalent to `ArrayView`, but implementing `__setitem__()` as well. |
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.. py:class:: corrade.containers.StridedArrayView1D |
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Provides one-dimensional read-only view on a memory range with custom |
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stride values. See `StridedArrayView2D`, `StridedArrayView3D`, |
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`MutableStridedArrayView1D` and others for multi-dimensional and mutable |
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equivalents. |
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`Comparison to Python's memoryview`_ |
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==================================== |
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The `StridedArrayView1D` and its multi-dimensional variants are equivalent |
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to any `memoryview`, but additionally supporting multi-dimensional slicing |
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as well (which raises `NotImplementedError` in Py3.7 `memoryview`). |
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.. py:class:: corrade.containers.MutableStridedArrayView1D |
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Equivalent to `StridedArrayView1D`, but implementing `__setitem__()` as |
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well. |
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.. py:class:: corrade.containers.StridedArrayView2D |
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See `StridedArrayView1D` for more information. |
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.. py:class:: corrade.containers.MutableStridedArrayView2D |
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See `StridedArrayView1D` and `MutableStridedArrayView1D` for more |
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information. |
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.. py:class:: corrade.containers.StridedArrayView3D |
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See `StridedArrayView1D` for more information. |
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.. py:class:: corrade.containers.MutableStridedArrayView3D |
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See `StridedArrayView1D` and `MutableStridedArrayView1D` for more |
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information.
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