Alexandria 2.31.0
SDC-CH common library for the Euclid project
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NpyReader.icpp
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1/*
2 * Copyright (C) 2012-2021 Euclid Science Ground Segment
3 *
4 * This library is free software; you can redistribute it and/or modify it under
5 * the terms of the GNU Lesser General Public License as published by the Free
6 * Software Foundation; either version 3.0 of the License, or (at your option)
7 * any later version.
8 *
9 * This library is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
11 * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
12 * details.
13 *
14 * You should have received a copy of the GNU Lesser General Public License
15 * along with this library; if not, write to the Free Software Foundation, Inc.,
16 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17 */
18
19#ifdef NPY_IMPL
20
21#include "NdArray/NdArray.h"
22#include "NpyCommon.h"
23#include <ElementsKernel/Exception.h>
24#include <cstring>
25#include <istream>
26
27namespace Euclid {
28namespace NdArray {
29
30using boost::endian::little_uint16_t;
31using boost::endian::little_uint32_t;
32
33template <typename T>
34NdArray<T> readNpy(std::istream& input) {
35 std::string dtype;
36 size_t n_elements;
37 std::vector<size_t> shape;
38 std::vector<std::string> attr_names;
39
40 readNpyHeader(input, dtype, shape, attr_names, n_elements);
41 if (dtype != NpyDtype<T>::str)
42 throw Elements::Exception() << "Can not cast " << dtype << " into " << typeid(T).name();
43
44 if (!attr_names.empty()) {
45 n_elements *= attr_names.size();
46 }
47
48 std::vector<T> data(n_elements);
49 input.read(reinterpret_cast<char*>(&data[0]), sizeof(T) * data.size());
50 return {shape, attr_names, std::move(data)};
51}
52
53} // end of namespace NdArray
54} // end of namespace Euclid
55
56#endif // NPY_IMPL