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109 lines
4.2 KiB
C++
109 lines
4.2 KiB
C++
/*
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pybind11/buffer_info.h: Python buffer object interface
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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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#pragma once
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#include "detail/common.h"
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NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
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/// Information record describing a Python buffer object
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struct buffer_info {
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void *ptr = nullptr; // Pointer to the underlying storage
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ssize_t itemsize = 0; // Size of individual items in bytes
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ssize_t size = 0; // Total number of entries
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std::string format; // For homogeneous buffers, this should be set to format_descriptor<T>::format()
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ssize_t ndim = 0; // Number of dimensions
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std::vector<ssize_t> shape; // Shape of the tensor (1 entry per dimension)
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std::vector<ssize_t> strides; // Number of entries between adjacent entries (for each per dimension)
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buffer_info() { }
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buffer_info(void *ptr, ssize_t itemsize, const std::string &format, ssize_t ndim,
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detail::any_container<ssize_t> shape_in, detail::any_container<ssize_t> strides_in)
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: ptr(ptr), itemsize(itemsize), size(1), format(format), ndim(ndim),
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shape(std::move(shape_in)), strides(std::move(strides_in)) {
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if (ndim != (ssize_t) shape.size() || ndim != (ssize_t) strides.size())
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pybind11_fail("buffer_info: ndim doesn't match shape and/or strides length");
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for (size_t i = 0; i < (size_t) ndim; ++i)
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size *= shape[i];
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}
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template <typename T>
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buffer_info(T *ptr, detail::any_container<ssize_t> shape_in, detail::any_container<ssize_t> strides_in)
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: buffer_info(private_ctr_tag(), ptr, sizeof(T), format_descriptor<T>::format(), static_cast<ssize_t>(shape_in->size()), std::move(shape_in), std::move(strides_in)) { }
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buffer_info(void *ptr, ssize_t itemsize, const std::string &format, ssize_t size)
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: buffer_info(ptr, itemsize, format, 1, {size}, {itemsize}) { }
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template <typename T>
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buffer_info(T *ptr, ssize_t size)
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: buffer_info(ptr, sizeof(T), format_descriptor<T>::format(), size) { }
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explicit buffer_info(Py_buffer *view, bool ownview = true)
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: buffer_info(view->buf, view->itemsize, view->format, view->ndim,
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{view->shape, view->shape + view->ndim}, {view->strides, view->strides + view->ndim}) {
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this->view = view;
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this->ownview = ownview;
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}
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buffer_info(const buffer_info &) = delete;
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buffer_info& operator=(const buffer_info &) = delete;
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buffer_info(buffer_info &&other) {
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(*this) = std::move(other);
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}
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buffer_info& operator=(buffer_info &&rhs) {
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ptr = rhs.ptr;
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itemsize = rhs.itemsize;
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size = rhs.size;
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format = std::move(rhs.format);
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ndim = rhs.ndim;
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shape = std::move(rhs.shape);
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strides = std::move(rhs.strides);
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std::swap(view, rhs.view);
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std::swap(ownview, rhs.ownview);
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return *this;
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}
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~buffer_info() {
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if (view && ownview) { PyBuffer_Release(view); delete view; }
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}
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private:
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struct private_ctr_tag { };
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buffer_info(private_ctr_tag, void *ptr, ssize_t itemsize, const std::string &format, ssize_t ndim,
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detail::any_container<ssize_t> &&shape_in, detail::any_container<ssize_t> &&strides_in)
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: buffer_info(ptr, itemsize, format, ndim, std::move(shape_in), std::move(strides_in)) { }
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Py_buffer *view = nullptr;
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bool ownview = false;
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};
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NAMESPACE_BEGIN(detail)
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template <typename T, typename SFINAE = void> struct compare_buffer_info {
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static bool compare(const buffer_info& b) {
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return b.format == format_descriptor<T>::format() && b.itemsize == (ssize_t) sizeof(T);
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}
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};
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template <typename T> struct compare_buffer_info<T, detail::enable_if_t<std::is_integral<T>::value>> {
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static bool compare(const buffer_info& b) {
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return (size_t) b.itemsize == sizeof(T) && (b.format == format_descriptor<T>::value ||
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((sizeof(T) == sizeof(long)) && b.format == (std::is_unsigned<T>::value ? "L" : "l")) ||
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((sizeof(T) == sizeof(size_t)) && b.format == (std::is_unsigned<T>::value ? "N" : "n")));
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}
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};
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NAMESPACE_END(detail)
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NAMESPACE_END(PYBIND11_NAMESPACE)
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