72 lines
2.3 KiB
C++
72 lines
2.3 KiB
C++
/**
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* @file Alignment.h
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* @author apio (cloudapio.eu)
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* @brief Functions to align addresses and sizes to specified boundaries.
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*
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* @copyright Copyright (c) 2022-2023, the Luna authors.
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*
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*/
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#pragma once
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#include <luna/Types.h>
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/**
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* @brief Check whether a value is aligned to a specific alignment.
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*
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* @tparam alignment The alignment to use. It must be provided as a template parameter to help the compiler with
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* optimizations. For best results, use a power of two.
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* @tparam T The type of the value.
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* @param value The value to check.
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* @return constexpr bool Whether the value is aligned.
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*/
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template <usize alignment, typename T> constexpr inline bool is_aligned(T value)
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{
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return (value % alignment == 0);
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}
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/**
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* @brief Find the closest aligned value that is smaller than the value provided.
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*
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* @tparam alignment The alignment to use. It must be provided as a template parameter to help the compiler with
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* optimizations. For best results, use a power of two.
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* @tparam T The type of the value.
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* @param value The value to use.
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* @return constexpr T The aligned value.
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*/
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template <usize alignment, typename T> constexpr inline T align_down(T value)
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{
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return value - value % alignment;
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}
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/**
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* @brief Find the closest aligned value that is bigger than the value provided.
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*
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* @tparam alignment The alignment to use. It must be provided as a template parameter to help the compiler with
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* optimizations. For best results, use a power of two.
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* @tparam T The type of the value.
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* @param value The value to use.
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* @return constexpr T The aligned value.
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*/
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template <usize alignment, typename T> constexpr inline T align_up(T value)
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{
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if (is_aligned<alignment>(value)) return value;
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return align_down<alignment>(value) + alignment;
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}
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/**
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* @brief Offset a pointer by exactly <offset> bytes, no matter the type.
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*
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* Generally only useful for pointers to void (or char), because breaking other pointers' alignments is not a good
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* idea...
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*
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* @tparam T The underlying type of the pointer.
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* @tparam Offset The type of the offset.
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* @param ptr The pointer to offset.
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* @param offset The offset to use (depending on the type, this could be negative).
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* @return constexpr T* The new pointer.
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*/
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template <typename T, typename Offset> constexpr inline T* offset_ptr(T* ptr, Offset offset)
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{
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return (T*)((u8*)ptr + offset);
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}
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