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/* fixed_vector.h */
/**************************************************************************/
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/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur. */
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#pragma once
#include "core/os/memory.h"
#include "core/templates/span.h"
GODOT_GCC_WARNING_PUSH_AND_IGNORE("-Warray-bounds")
/**
* A high performance Vector of fixed capacity.
* Especially useful if you need to create an array on the stack, to
* prevent dynamic allocations (especially in bottleneck code).
*
* Choose CAPACITY such that it is enough for all elements that could be added through all branches.
*
*/
template <class T, uint32_t CAPACITY>
class FixedVector {
// This declaration allows us to access other FixedVector's private members.
template <class T_, uint32_t CAPACITY_>
friend class FixedVector;
uint32_t _size = 0;
alignas(T) uint8_t _data[CAPACITY * sizeof(T)];
constexpr static uint32_t DATA_PADDING = MAX(alignof(T), alignof(uint32_t)) - alignof(uint32_t);
public:
_FORCE_INLINE_ constexpr FixedVector() = default;
constexpr FixedVector(std::initializer_list<T> p_init) {
ERR_FAIL_COND(p_init.size() > CAPACITY);
for (const T &element : p_init) {
memnew_placement(ptr() + _size++, T(element));
}
}
constexpr FixedVector(const FixedVector &p_from) {
if constexpr (std::is_trivially_copyable_v<T>) {
// Copy size and all provided elements at once.
memcpy((void *)&_size, (void *)&p_from._size, sizeof(_size) + DATA_PADDING + p_from.size() * sizeof(T));
} else {
for (const T &element : p_from) {
memnew_placement(ptr() + _size++, T(element));
}
}
}
constexpr FixedVector(FixedVector &&p_from) {
// Copy size and all provided elements at once.
// Note: Assumes trivial relocatability.
memcpy((void *)&_size, (void *)&p_from._size, sizeof(_size) + DATA_PADDING + p_from.size() * sizeof(T));
p_from._size = 0;
}
constexpr FixedVector &operator=(const FixedVector &p_from) {
if constexpr (std::is_trivially_copyable_v<T>) {
// Copy size and all provided elements at once.
memcpy((void *)&_size, (void *)&p_from._size, sizeof(_size) + DATA_PADDING + p_from.size() * sizeof(T));
} else {
// Destruct extraneous elements.
if constexpr (!std::is_trivially_destructible_v<T>) {
for (uint32_t i = p_from.size(); i < _size; i++) {
ptr()[i].~T();
}
}
_size = 0; // Loop-assign the rest.
for (const T &element : p_from) {
ptr()[_size++] = element;
}
}
return *this;
}
constexpr FixedVector &operator=(FixedVector &&p_from) {
// Destruct extraneous elements.
if constexpr (!std::is_trivially_destructible_v<T>) {
for (uint32_t i = p_from.size(); i < _size; i++) {
ptr()[i].~T();
}
}
// Relocate elements (and size) into our buffer.
memcpy((void *)&_size, (void *)&p_from._size, sizeof(_size) + DATA_PADDING + p_from.size() * sizeof(T));
p_from._size = 0;
return *this;
}
~FixedVector() {
if constexpr (!std::is_trivially_destructible_v<T>) {
for (uint32_t i = 0; i < _size; i++) {
ptr()[i].~T();
}
}
}
_FORCE_INLINE_ constexpr T *ptr() { return (T *)(_data); }
_FORCE_INLINE_ constexpr const T *ptr() const { return (const T *)(_data); }
_FORCE_INLINE_ constexpr operator Span<T>() const { return Span<T>(ptr(), size()); }
_FORCE_INLINE_ constexpr Span<T> span() const { return operator Span<T>(); }
_FORCE_INLINE_ constexpr uint32_t size() const { return _size; }
_FORCE_INLINE_ constexpr bool is_empty() const { return !_size; }
_FORCE_INLINE_ constexpr bool is_full() const { return _size == CAPACITY; }
_FORCE_INLINE_ constexpr uint32_t capacity() const { return CAPACITY; }
_FORCE_INLINE_ constexpr void clear() { resize_initialized(0); }
/// Changes the size of the vector.
/// If p_size > size(), constructs new elements.
/// If p_size < size(), destructs new elements.
constexpr Error resize_initialized(uint32_t p_size) {
if (p_size > _size) {
ERR_FAIL_COND_V(p_size > CAPACITY, ERR_OUT_OF_MEMORY);
memnew_arr_placement(ptr() + _size, p_size - _size);
} else if (p_size < _size) {
if constexpr (!std::is_trivially_destructible_v<T>) {
for (uint32_t i = p_size; i < _size; i++) {
ptr()[i].~T();
}
}
}
_size = p_size;
return OK;
}
/// Changes the size of the vector.
/// The initializer of new elements is skipped, making this function faster than resize_initialized.
/// The caller is required to initialize the new values.
constexpr Error resize_uninitialized(uint32_t p_size) {
static_assert(std::is_trivially_destructible_v<T>, "resize_uninitialized is unsafe to call if T is not trivially destructible.");
ERR_FAIL_COND_V(p_size > CAPACITY, ERR_OUT_OF_MEMORY);
_size = p_size;
return OK;
}
constexpr void push_back(const T &p_val) {
ERR_FAIL_COND(_size >= CAPACITY);
memnew_placement(ptr() + _size, T(p_val));
_size++;
}
constexpr void push_back(T &&p_val) {
ERR_FAIL_COND(_size >= CAPACITY);
memnew_placement(ptr() + _size, T(std::move(p_val)));
_size++;
}
constexpr void pop_back() {
ERR_FAIL_COND(_size == 0);
_size--;
ptr()[_size].~T();
}
// NOTE: Subscripts sanity check the bounds to avoid undefined behavior.
// This is slower than direct buffer access and can prevent autovectorization.
// If the bounds are known, use ptr() subscript instead.
constexpr const T &operator[](uint32_t p_index) const {
CRASH_COND(p_index >= _size);
return ptr()[p_index];
}
constexpr T &operator[](uint32_t p_index) {
CRASH_COND(p_index >= _size);
return ptr()[p_index];
}
_FORCE_INLINE_ constexpr T *begin() { return ptr(); }
_FORCE_INLINE_ constexpr T *end() { return ptr() + _size; }
_FORCE_INLINE_ constexpr const T *begin() const { return ptr(); }
_FORCE_INLINE_ constexpr const T *end() const { return ptr() + _size; }
};
GODOT_GCC_WARNING_POP