3d游戏引擎的Utilities模块实现

1.Vector.h

#pragma once

#include "CommonHeaders.h"

namespace primal::utl

{

template<typename T, bool destruct = true>

class vector

{

public:

vector() = default;

constexpr vector(u64 count)

{

resize(count);

}

constexpr explicit vector(u64 count, const T& value)

{

resize(count,value);

}

/*

template<typename it,typename = std::enable_if_t<std::_Is_iterator_v<it>,int> = 0>

constexpr explicit vector(it first, it last)

{

for (; first != last; ++first)

{

emplace_back(*first);

}

}

*/

constexpr vector(const vector& o)

{

*this = o;

}

constexpr vector(vector&& o)

: _capacity{ o._capacity }, _size{ o.size }, _data{o.data}

{

o.reset();

}

constexpr vector& operator=(const vector& o)

{

assert(this != std::addressof(o));

if (this != std::addressof(o))

{

clear();

reserve(o._size);

for (auto& item : o)

{

emplace_back(item);

}

assert(_size == o._size);

}

return *this;

}

constexpr vector& operator=(vector&& o)

{

assert(this != std::addressof(o));

if (this != std::addressof(o))

{

destroy();

move(o);

}

return *this;

}

~vector() { destroy(); }

constexpr void push_back(const T& value)

{

emplace_back(value);

}

constexpr void push_back(T&& value)

{

emplace_back(std::move(value));

}

template<typename... params>

constexpr decltype(auto) emplace_back(params&&... p)

{

if (_size == _capacity)

{

reserve(((_capacity + 1) * 3) >> 1);

}

assert(_size < _capacity);

T* const item{ new(std::addressof(_data[_size])) T(std::forward<params>(p)...); };

++_size;

return *item;

}

constexpr void resize(u64 new_size)

{

static_assert(std::is_default_constructible_v<T>::value,

"Type must be default-constructable."

);

if (new_size > _size)

{

reserve(new_size);

while (_size < new_size)

{

emplace_back();

}

}

else

{

if constexpr (destruct)

{

destruct_range(new_size, _size);

}

_size = new_size;

}

assert(new_size == _size);

}

constexpr void resize(u64 new_size,const T& value)

{

static_assert(std::is_copy_constructible_v<T>::value,

"Type must be copy-constructable."

);

if (new_size > _size)

{

reserve(new_size);

while (_size < new_size)

{

emplace_back(value);

}

}

else

{

if constexpr (destruct)

{

destruct_range(new_size, _size);

}

_size = new_size;

}

assert(new_size == _size);

}

constexpr void reserve(u64 new_capacity)

{

if (new_capacity > _capacity)

{

void* new_buffer{ realloc(_data,new_capacity * sizeof(T)) };

if (new_buffer)

{

_data = static_cast<T*>(new_buffer);

_capacity = new_capacity;

}

}

}

constexpr T* const erase(u64 index)

{

assert(_data && index < _size);

return erase(std::addressof(_data[index]));

}

constexpr T* const erase(T* const item)

{

assert(_data && item >= std::addressof(_data[0]) &&

item < std::addressof(_data[_size])

);

if constexpr (destruct) item->~T();

--_size;

if (item < std::addressof(_data[_size]))

{

memcpy(item, item + 1, (std::addressof(_data[_size]) - item) * sizeof(T));

}

return item;

}

constexpr T* const erase_unordered(u64 index)

{

assert(_data && index < _size);

return erase_unordered(std::addressof(_data[index]));

}

constexpr T* const erase_unordered(T* const item)

{

assert(_data && item >= std::addressof(_data[0]) &&

item < std::addressof(_data[_size])

);

if constexpr (destruct) item->~T();

--_size;

if (item < std::addressof(_data[_size]))

{

memcpy(item, std::addressof(_data[_size]), sizeof(T));

}

return item;

}

constexpr void clear()

{

if constexpr (destruct)

{

destruct_range(0, _size);

}

_size = 0;

}

constexpr void swap(vector& o)

{

if (this != std::addressof(o))

{

auto temp(std::move(o));

o.move(*this);

move(temp);

}

}

\[nodiscard\]\] constexpr T\* data() { return _data; } \[\[nodiscard\]\] constexpr T\* const data() const { return _data; } \[\[nodiscard\]\] constexpr bool empty() const { return _size == 0; } \[\[nodiscard\]\] constexpr u64 size() const { return _size; } \[\[nodiscard\]\] constexpr u64 capacity() const { return _capacity; } \[\[nodiscard\]\] constexpr T\& operator\[\](u64 index) { assert(_data \&\& index \< _size); return _data\[index\]; } \[\[nodiscard\]\] constexpr const T\& operator\[\](u64 index) const { assert(_data \&\& index \< _size); return _data\[index\]; } \[\[nodiscard\]\] constexpr T\& front() { assert(_data \&\& _size); return _data\[0\]; } \[\[nodiscard\]\] constexpr const T\& front() const { assert(_data \&\& _size); return _data\[0\]; } \[\[nodiscard\]\] constexpr T\& back() { assert(_data \&\& _size); return _data\[_size - 1\]; } \[\[nodiscard\]\] constexpr const T\& back() const { assert(_data \&\& _size); return _data\[_size - 1\]; } \[\[nodiscard\]\] constexpr T\* begin() { assert(_data); return std::addressof(_data\[0\]); } \[\[nodiscard\]\] constexpr const T\* begin() const { assert(_data); return std::addressof(_data\[0\]); } \[\[nodiscard\]\] constexpr T\* end() { assert(_data); return std::addressof(_data\[_size\]); } \[\[nodiscard\]\] constexpr const T\* end() const { assert(_data); return std::addressof(_data\[_size\]); } private: constexpr void move(vector\& o) { _capacity = o._capacity; _size = o._size; _data = o._data; o.reset(); } constexpr void reset() { _capacity = 0; _size = 0; _data = nullptr; } constexpr void destruct_range(u64 first, u64 last) { assert(destruct); assert(first \<= _size \&\& last \<= _size \&\& first \<= last); if (_data) { for (; first != last; ++first) { _data\[first\].\~T(); } } } constexpr void destroy() { assert(\[\&\] {return _capacity ? _data != nullptr : _data == nullptr; }()); clear(); _capacity = 0; if (_data) free(_data); _data = nullptr; } u64 _capacity{ 0 }; u64 _size{ 0 }; T\* _data{ nullptr }; }; }

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