std::layout_left::mapping(3)

💅 std::layout_left::mapping(3) — C++ Standard Libary 💅

🌸 NAME 🌸

std::layout_left::mapping — std::layout_left::mapping

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✨ Synopsis ✨

Defined in header <mdspan>
template< class Extents >    (since C++23)
class layout_left::mapping;

Okay so the class template layout_left::mapping controls how multidimensional indices are mapped in a column-major manner to a one-dimensional value representing the offset. The mapping has stride 1 at leftmost extent and strides increase left-to-right as the products of extents. It’s giving column-major main character energy, no cap. 🔥

Every specialization of mapping is a LayoutMapping and a TriviallyCopyable type which satisfies regular. 💖

🚨 Heads up, bestie: the program is ill-formed if the size of the multidimensional index space Extents() is not representable as a value of type Extents::index_type when Extents::rank_dynamic() is 0. That’s a hard error, fr fr. 💀

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🧚 Template parameters 🧚

• Extents — specifies number of dimensions, their sizes, and which are known at compile time. Must be a specialization of std::extents.

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👑 Member types 👑

Member type → definition, slay:

• extents_type — Extents
• index_type — extents_type::index_type
• size_type — extents_type::size_type
• rank_type — extents_type::rank_type
• layout_type — std::layout_left

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🎀 Member objects 🎀

• extents_ (private) — The extents of type extents_type. (exposition-only member object*)

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🦋 Member functions 🦋

• constructor — constructs a new mapping (public member function)
• operator= — assigns a mapping (public member function)

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🔥 Observers 🔥

• extents — obtains the extents object (public member function)
• required_span_size — returns the required size of the mapping (public member function)
• operator() — maps multidimensional indices into an offset value (public member function)
• is_unique [static] — determines if this mapping is unique (every combination of indexes maps to a different underlying element) (public static member function)
• is_exhaustive [static] — determines if this mapping is exhaustive (every underlying element can be accessed with some combination of indexes) (public static member function)
• is_strided [static] — determines if this mapping is unique (every combination of indexes maps to a different underlying element) (public static member function)
• is_always_unique [static] — determines if this layout mapping is always unique (public static member function)
• is_always_exhaustive [static] — determines if this layout mapping is always exhaustive (public static member function)
• is_always_strided [static] — determines if this layout mapping is always strided (public static member function)
• stride — obtains the stride along the specified dimension (public member function)

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💜 Non-member functions 💜

• operator== — compares this layout mapping with other mapping (function template)
• submdspan_mapping(std::layout_left::mapping) (C++26) — calculates the mapping and data handle offset used for subdmspan (public member function)

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🌈 See also 🌈

• mapping — a layout mapping of layout_right (public member class template of std::layout_right)
• mapping — a layout mapping of layout_stride (public member class template of std::layout_stride)

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Source: http://cppreference.com · version/date: 2024.06.10 · page: std::layout_left::mapping(3). Byeee, bestie 💖✨