259 lines
9.0 KiB
C++
259 lines
9.0 KiB
C++
/*
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* Copyright 2015 - 2024 gary@drinkingtea.net
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at https://mozilla.org/MPL/2.0/.
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*/
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#pragma once
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#include <ox/std/std.hpp>
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namespace ox::ptrarith {
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template<typename T, typename size_t, size_t minOffset = 1>
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class [[nodiscard]] Ptr {
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private:
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uint8_t *m_dataStart = nullptr;
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size_t m_dataSize = 0;
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size_t m_itemOffset = 0;
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size_t m_itemSize = 0;
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// this should be removed later on, but the excessive validation is
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// desirable during during heavy development
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mutable uint8_t m_validated = false;
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public:
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constexpr Ptr() noexcept = default;
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constexpr Ptr(std::nullptr_t) noexcept;
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constexpr Ptr(
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void *pDataStart,
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std::size_t pDataSize,
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std::size_t pItemStart,
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std::size_t pItemSize = sizeof(T),
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std::size_t pItemTypeSize = sizeof(T),
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bool pPrevalidated = false) noexcept;
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[[nodiscard]]
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constexpr bool valid() const noexcept;
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constexpr size_t size() const noexcept;
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constexpr size_t offset() const noexcept;
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constexpr size_t end() noexcept;
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constexpr const T *get() const noexcept;
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constexpr T *get() noexcept;
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constexpr const T *operator->() const noexcept;
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constexpr T *operator->() noexcept;
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constexpr operator const T*() const noexcept;
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constexpr operator T*() noexcept;
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constexpr const T &operator*() const noexcept;
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constexpr T &operator*() noexcept;
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constexpr operator size_t() const noexcept;
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constexpr bool operator==(const Ptr<T, size_t, minOffset> &other) const noexcept;
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constexpr bool operator!=(const Ptr<T, size_t, minOffset> &other) const noexcept;
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template<typename SubT>
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constexpr const Ptr<SubT, size_t, sizeof(T)> subPtr(size_t offset, size_t size) const noexcept;
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template<typename SubT>
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constexpr const Ptr<SubT, size_t, sizeof(T)> subPtr(size_t offset) const noexcept;
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template<typename SubT>
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constexpr Ptr<SubT, size_t, sizeof(T)> subPtr(size_t offset, size_t size) noexcept;
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template<typename SubT>
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constexpr Ptr<SubT, size_t, sizeof(T)> subPtr(size_t offset) noexcept;
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template<typename SubT>
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constexpr const Ptr<SubT, size_t, minOffset> to() const noexcept;
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constexpr Result<Ptr<T, size_t, minOffset>> validate() const noexcept;
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};
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template<typename T, typename size_t, size_t minOffset>
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constexpr Ptr<T, size_t, minOffset>::Ptr(std::nullptr_t) noexcept {
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}
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template<typename T, typename size_t, size_t minOffset>
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constexpr Ptr<T, size_t, minOffset>::Ptr(
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void *pDataStart,
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std::size_t pDataSize,
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std::size_t pItemStart,
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std::size_t pItemSize,
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std::size_t pItemTypeSize,
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bool pPrevalidated) noexcept {
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const auto dataSize = static_cast<size_t>(pDataSize);
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const auto itemStart = static_cast<size_t>(pItemStart);
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const auto itemSize = static_cast<size_t>(pItemSize);
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const auto itemTypeSize = static_cast<size_t>(pItemTypeSize);
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// do some sanity checks before assuming this is valid
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if (itemSize >= itemTypeSize &&
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pDataStart &&
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itemStart >= minOffset &&
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itemStart + itemSize <= dataSize) {
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m_dataStart = reinterpret_cast<uint8_t*>(pDataStart);
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m_dataSize = dataSize;
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m_itemOffset = itemStart;
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m_itemSize = itemSize;
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m_validated = pPrevalidated;
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}
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}
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template<typename T, typename size_t, size_t minOffset>
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constexpr bool Ptr<T, size_t, minOffset>::valid() const noexcept {
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m_validated = m_dataStart != nullptr;
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return m_validated;
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}
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template<typename T, typename size_t, size_t minOffset>
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constexpr size_t Ptr<T, size_t, minOffset>::size() const noexcept {
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return m_itemSize;
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}
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template<typename T, typename size_t, size_t minOffset>
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constexpr size_t Ptr<T, size_t, minOffset>::offset() const noexcept {
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return m_itemOffset;
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}
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template<typename T, typename size_t, size_t minOffset>
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constexpr size_t Ptr<T, size_t, minOffset>::end() noexcept {
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return m_itemOffset + m_itemSize;
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}
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template<typename T, typename size_t, size_t minOffset>
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constexpr const T *Ptr<T, size_t, minOffset>::get() const noexcept {
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oxAssert(m_validated, "Unvalidated pointer access. (ox::fs::Ptr::get())");
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oxAssert(valid(), "Invalid pointer access. (ox::fs::Ptr::get())");
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return reinterpret_cast<T*>(m_dataStart + m_itemOffset);
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}
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template<typename T, typename size_t, size_t minOffset>
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constexpr T *Ptr<T, size_t, minOffset>::get() noexcept {
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oxAssert(m_validated, "Unvalidated pointer access. (ox::fs::Ptr::get())");
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oxAssert(valid(), "Invalid pointer access. (ox::fs::Ptr::get())");
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return reinterpret_cast<T*>(m_dataStart + m_itemOffset);
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}
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template<typename T, typename size_t, size_t minOffset>
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constexpr const T *Ptr<T, size_t, minOffset>::operator->() const noexcept {
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oxAssert(m_validated, "Unvalidated pointer access. (ox::fs::Ptr::operator->())");
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oxAssert(valid(), "Invalid pointer access. (ox::fs::Ptr::operator->())");
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return reinterpret_cast<T*>(m_dataStart + m_itemOffset);
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}
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template<typename T, typename size_t, size_t minOffset>
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constexpr T *Ptr<T, size_t, minOffset>::operator->() noexcept {
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oxAssert(m_validated, "Unvalidated pointer access. (ox::fs::Ptr::operator->())");
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oxAssert(valid(), "Invalid pointer access. (ox::fs::Ptr::operator->())");
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return reinterpret_cast<T*>(m_dataStart + m_itemOffset);
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}
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template<typename T, typename size_t, size_t minOffset>
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constexpr Ptr<T, size_t, minOffset>::operator const T*() const noexcept {
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oxAssert(m_validated, "Unvalidated pointer access. (ox::fs::Ptr::operator const T*())");
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oxAssert(valid(), "Invalid pointer access. (ox::fs::Ptr::operator const T*())");
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return reinterpret_cast<T*>(m_dataStart + m_itemOffset);
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}
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template<typename T, typename size_t, size_t minOffset>
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constexpr Ptr<T, size_t, minOffset>::operator T*() noexcept {
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oxAssert(m_validated, "Unvalidated pointer access. (ox::fs::Ptr::operator T*())");
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oxAssert(valid(), "Invalid pointer access. (ox::fs::Ptr::operator T*())");
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return reinterpret_cast<T*>(m_dataStart + m_itemOffset);
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}
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template<typename T, typename size_t, size_t minOffset>
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constexpr const T &Ptr<T, size_t, minOffset>::operator*() const noexcept {
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oxAssert(m_validated, "Unvalidated pointer dereference. (ox::fs::Ptr::operator*())");
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oxAssert(valid(), "Invalid pointer dereference. (ox::fs::Ptr::operator*())");
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return *reinterpret_cast<T*>(m_dataStart + m_itemOffset);
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}
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template<typename T, typename size_t, size_t minOffset>
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constexpr T &Ptr<T, size_t, minOffset>::operator*() noexcept {
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oxAssert(m_validated, "Unvalidated pointer dereference. (ox::fs::Ptr::operator*())");
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oxAssert(valid(), "Invalid pointer dereference. (ox::fs::Ptr::operator*())");
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return *reinterpret_cast<T*>(m_dataStart + m_itemOffset);
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}
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template<typename T, typename size_t, size_t minOffset>
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constexpr Ptr<T, size_t, minOffset>::operator size_t() const noexcept {
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if (m_dataStart && m_itemOffset) {
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return m_itemOffset;
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}
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return 0;
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}
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template<typename T, typename size_t, size_t minOffset>
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constexpr bool Ptr<T, size_t, minOffset>::operator==(const Ptr<T, size_t, minOffset> &other) const noexcept {
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return m_dataStart == other.m_dataStart &&
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m_itemOffset == other.m_itemOffset &&
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m_itemSize == other.m_itemSize;
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}
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template<typename T, typename size_t, size_t minOffset>
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constexpr bool Ptr<T, size_t, minOffset>::operator!=(const Ptr<T, size_t, minOffset> &other) const noexcept {
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return m_dataStart != other.m_dataStart ||
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m_itemOffset != other.m_itemOffset ||
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m_itemSize != other.m_itemSize;
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}
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template<typename T, typename size_t, size_t minOffset>
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template<typename SubT>
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constexpr const Ptr<SubT, size_t, sizeof(T)> Ptr<T, size_t, minOffset>::subPtr(size_t offset, size_t size) const noexcept {
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return Ptr<SubT, size_t, sizeof(T)>(get(), this->size(), offset, size);
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}
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template<typename T, typename size_t, size_t minOffset>
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template<typename SubT>
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constexpr const Ptr<SubT, size_t, sizeof(T)> Ptr<T, size_t, minOffset>::subPtr(size_t offset) const noexcept {
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oxTracef("ox.fs.Ptr.subPtr", "{} {} {} {} {}", m_itemOffset, this->size(), offset, m_itemSize, (m_itemSize - offset));
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return subPtr<SubT>(offset, m_itemSize - offset);
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}
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template<typename T, typename size_t, size_t minOffset>
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template<typename SubT>
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constexpr Ptr<SubT, size_t, sizeof(T)> Ptr<T, size_t, minOffset>::subPtr(size_t offset, size_t size) noexcept {
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return Ptr<SubT, size_t, sizeof(T)>(get(), this->size(), offset, size);
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}
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template<typename T, typename size_t, size_t minOffset>
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template<typename SubT>
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constexpr Ptr<SubT, size_t, sizeof(T)> Ptr<T, size_t, minOffset>::subPtr(size_t offset) noexcept {
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oxTracef("ox.fs.Ptr.subPtr", "{} {} {} {} {}", m_itemOffset, this->size(), offset, m_itemSize, (m_itemSize - offset));
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return subPtr<SubT>(offset, m_itemSize - offset);
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}
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template<typename T, typename size_t, size_t minOffset>
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template<typename SubT>
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constexpr const Ptr<SubT, size_t, minOffset> Ptr<T, size_t, minOffset>::to() const noexcept {
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return Ptr<SubT, size_t, minOffset>(m_dataStart, m_dataSize, m_itemOffset, m_itemSize);
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}
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template<typename T, typename size_t, size_t minOffset>
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constexpr Result<Ptr<T, size_t, minOffset>> Ptr<T, size_t, minOffset>::validate() const noexcept {
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if (valid()) {
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return *this;
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}
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return OxError(1);
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}
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}
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