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115 lines
4.1 KiB
115 lines
4.1 KiB
/*
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example/example7.cpp -- supporting Pythons' buffer protocol
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Copyright (c) 2016 Wenzel Jakob <wenzel.jakob@epfl.ch>
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All rights reserved. Use of this source code is governed by a
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BSD-style license that can be found in the LICENSE file.
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*/
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#include "example.h"
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class Matrix {
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public:
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Matrix(size_t rows, size_t cols) : m_rows(rows), m_cols(cols) {
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std::cout << "Value constructor: Creating a " << rows << "x" << cols << " matrix " << std::endl;
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m_data = new float[rows*cols];
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memset(m_data, 0, sizeof(float) * rows * cols);
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}
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Matrix(const Matrix &s) : m_rows(s.m_rows), m_cols(s.m_cols) {
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std::cout << "Copy constructor: Creating a " << m_rows << "x" << m_cols << " matrix " << std::endl;
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m_data = new float[m_rows * m_cols];
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memcpy(m_data, s.m_data, sizeof(float) * m_rows * m_cols);
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}
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Matrix(Matrix &&s) : m_rows(s.m_rows), m_cols(s.m_cols), m_data(s.m_data) {
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std::cout << "Move constructor: Creating a " << m_rows << "x" << m_cols << " matrix " << std::endl;
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s.m_rows = 0;
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s.m_cols = 0;
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s.m_data = nullptr;
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}
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~Matrix() {
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std::cout << "Freeing a " << m_rows << "x" << m_cols << " matrix " << std::endl;
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delete[] m_data;
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}
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Matrix &operator=(const Matrix &s) {
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std::cout << "Assignment operator : Creating a " << s.m_rows << "x" << s.m_cols << " matrix " << std::endl;
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delete[] m_data;
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m_rows = s.m_rows;
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m_cols = s.m_cols;
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m_data = new float[m_rows * m_cols];
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memcpy(m_data, s.m_data, sizeof(float) * m_rows * m_cols);
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return *this;
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}
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Matrix &operator=(Matrix &&s) {
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std::cout << "Move assignment operator : Creating a " << s.m_rows << "x" << s.m_cols << " matrix " << std::endl;
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if (&s != this) {
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delete[] m_data;
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m_rows = s.m_rows; m_cols = s.m_cols; m_data = s.m_data;
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s.m_rows = 0; s.m_cols = 0; s.m_data = nullptr;
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}
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return *this;
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}
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float operator()(size_t i, size_t j) const {
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return m_data[i*m_cols + j];
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}
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float &operator()(size_t i, size_t j) {
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return m_data[i*m_cols + j];
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}
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float *data() { return m_data; }
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size_t rows() const { return m_rows; }
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size_t cols() const { return m_cols; }
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private:
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size_t m_rows;
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size_t m_cols;
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float *m_data;
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};
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void init_ex7(py::module &m) {
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py::class_<Matrix> mtx(m, "Matrix");
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mtx.def(py::init<size_t, size_t>())
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/// Construct from a buffer
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.def("__init__", [](Matrix &v, py::buffer b) {
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py::buffer_info info = b.request();
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if (info.format != py::format_descriptor<float>::value || info.ndim != 2)
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throw std::runtime_error("Incompatible buffer format!");
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new (&v) Matrix(info.shape[0], info.shape[1]);
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memcpy(v.data(), info.ptr, sizeof(float) * v.rows() * v.cols());
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})
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.def("rows", &Matrix::rows)
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.def("cols", &Matrix::cols)
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/// Bare bones interface
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.def("__getitem__", [](const Matrix &m, std::pair<size_t, size_t> i) {
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if (i.first >= m.rows() || i.second >= m.cols())
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throw py::index_error();
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return m(i.first, i.second);
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})
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.def("__setitem__", [](Matrix &m, std::pair<size_t, size_t> i, float v) {
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if (i.first >= m.rows() || i.second >= m.cols())
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throw py::index_error();
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m(i.first, i.second) = v;
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})
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/// Provide buffer access
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.def_buffer([](Matrix &m) -> py::buffer_info {
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return py::buffer_info(
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m.data(), /* Pointer to buffer */
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sizeof(float), /* Size of one scalar */
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py::format_descriptor<float>::value, /* Python struct-style format descriptor */
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2, /* Number of dimensions */
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{ m.rows(), m.cols() }, /* Buffer dimensions */
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{ sizeof(float) * m.rows(), /* Strides (in bytes) for each index */
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sizeof(float) }
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);
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});
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}
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