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/*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#pragma once
/** \file
* \ingroup bli
*
* A `blender::Array<T>` is a container for a fixed size array the size of which is NOT known at
* compile time.
*
* If the size is known at compile time, `std::array<T, N>` should be used instead.
*
* blender::Array should usually be used instead of blender::Vector whenever the number of elements
* is known at construction time. Note however, that blender::Array will default construct all
* elements when initialized with the size-constructor. For trivial types, this does nothing. In
* all other cases, this adds overhead.
*
* A main benefit of using Array over Vector is that it expresses the intent of the developer
* better. It indicates that the size of the data structure is not expected to change. Furthermore,
* you can be more certain that an array does not overallocate.
*
* blender::Array supports small object optimization to improve performance when the size turns out
* to be small at run-time.
*/
#include "BLI_allocator.hh"
#include "BLI_index_range.hh"
#include "BLI_memory_utils.hh"
#include "BLI_span.hh"
#include "BLI_utildefines.h"
namespace blender {
template<
/**
* The type of the values stored in the array.
*/
typename T,
/**
* The number of values that can be stored in the array, without doing a heap allocation.
*/
int64_t InlineBufferCapacity = default_inline_buffer_capacity(sizeof(T)),
/**
* The allocator used by this array. Should rarely be changed, except when you don't want that
* MEM_* functions are used internally.
*/
typename Allocator = GuardedAllocator>
class Array {
private:
/** The beginning of the array. It might point into the inline buffer. */
T *data_;
/** Number of elements in the array. */
int64_t size_;
/** Used for allocations when the inline buffer is too small. */
Allocator allocator_;
/** A placeholder buffer that will remain uninitialized until it is used. */
TypedBuffer<T, InlineBufferCapacity> inline_buffer_;
public:
/**
* By default an empty array is created.
*/
Array(Allocator allocator = {}) noexcept : allocator_(allocator)
{
data_ = inline_buffer_;
size_ = 0;
}
Array(NoExceptConstructor, Allocator allocator = {}) noexcept : Array(allocator)
{
}
/**
* Create a new array that contains copies of all values.
*/
template<typename U, typename std::enable_if_t<std::is_convertible_v<U, T>> * = nullptr>
Array(Span<U> values, Allocator allocator = {}) : Array(NoExceptConstructor(), allocator)
{
const int64_t size = values.size();
data_ = this->get_buffer_for_size(size);
uninitialized_convert_n<U, T>(values.data(), size, data_);
size_ = size;
}
/**
* Create a new array that contains copies of all values.
*/
template<typename U, typename std::enable_if_t<std::is_convertible_v<U, T>> * = nullptr>
Array(const std::initializer_list<U> &values, Allocator allocator = {})
: Array(Span<U>(values), allocator)
{
}
Array(const std::initializer_list<T> &values, Allocator allocator = {})
: Array(Span<T>(values), allocator)
{
}
/**
* Create a new array with the given size. All values will be default constructed. For trivial
* types like int, default construction does nothing.
*
* We might want another version of this in the future, that does not do default construction
* even for non-trivial types. This should not be the default though, because one can easily mess
* up when dealing with uninitialized memory.
*/
explicit Array(int64_t size, Allocator allocator = {}) : Array(NoExceptConstructor(), allocator)
{
data_ = this->get_buffer_for_size(size);
default_construct_n(data_, size);
size_ = size;
}
/**
* Create a new array with the given size. All values will be initialized by copying the given
* default.
*/
Array(int64_t size, const T &value, Allocator allocator = {})
: Array(NoExceptConstructor(), allocator)
{
BLI_assert(size >= 0);
data_ = this->get_buffer_for_size(size);
uninitialized_fill_n(data_, size, value);
size_ = size;
}
/**
* Create a new array with uninitialized elements. The caller is responsible for constructing the
* elements. Moving, copying or destructing an Array with uninitialized elements invokes
* undefined behavior.
*
* This should be used very rarely. Note, that the normal size-constructor also does not
* initialize the elements when T is trivially constructible. Therefore, it only makes sense to
* use this with non trivially constructible types.
*
* Usage:
* Array<std::string> my_strings(10, NoInitialization());
*/
Array(int64_t size, NoInitialization, Allocator allocator = {})
: Array(NoExceptConstructor(), allocator)
{
BLI_assert(size >= 0);
data_ = this->get_buffer_for_size(size);
size_ = size;
}
Array(const Array &other) : Array(other.as_span(), other.allocator_)
{
}
Array(Array &&other) noexcept(std::is_nothrow_move_constructible_v<T>)
: Array(NoExceptConstructor(), other.allocator_)
{
if (other.uses_inline_buffer()) {
uninitialized_relocate_n(other.data_, other.size_, data_);
}
else {
data_ = other.data_;
}
size_ = other.size_;
other.data_ = other.inline_buffer_;
other.size_ = 0;
}
~Array()
{
destruct_n(data_, size_);
if (!this->uses_inline_buffer()) {
allocator_.deallocate(static_cast<void *>(data_));
}
}
Array &operator=(const Array &other)
{
return copy_assign_container(*this, other);
}
Array &operator=(Array &&other) noexcept(std::is_nothrow_move_constructible_v<T>)
{
return move_assign_container(*this, std::move(other));
}
T &operator[](int64_t index)
{
BLI_assert(index >= 0);
BLI_assert(index < size_);
return data_[index];
}
const T &operator[](int64_t index) const
{
BLI_assert(index >= 0);
BLI_assert(index < size_);
return data_[index];
}
operator Span<T>() const
{
return Span<T>(data_, size_);
}
operator MutableSpan<T>()
{
return MutableSpan<T>(data_, size_);
}
template<typename U, typename std::enable_if_t<is_convertible_pointer_v<T, U>> * = nullptr>
operator Span<U>() const
{
return Span<U>(data_, size_);
}
template<typename U, typename std::enable_if_t<is_convertible_pointer_v<T, U>> * = nullptr>
operator MutableSpan<U>()
{
return MutableSpan<U>(data_, size_);
}
Span<T> as_span() const
{
return *this;
}
MutableSpan<T> as_mutable_span()
{
return *this;
}
/**
* Returns the number of elements in the array.
*/
int64_t size() const
{
return size_;
}
/**
* Returns true when the number of elements in the array is zero.
*/
bool is_empty() const
{
return size_ == 0;
}
/**
* Copies the given value to every element in the array.
*/
void fill(const T &value) const
{
initialized_fill_n(data_, size_, value);
}
/**
* Get a pointer to the beginning of the array.
*/
const T *data() const
{
return data_;
}
T *data()
{
return data_;
}
const T *begin() const
{
return data_;
}
const T *end() const
{
return data_ + size_;
}
T *begin()
{
return data_;
}
T *end()
{
return data_ + size_;
}
std::reverse_iterator<T *> rbegin()
{
return std::reverse_iterator<T *>(this->end());
}
std::reverse_iterator<T *> rend()
{
return std::reverse_iterator<T *>(this->begin());
}
std::reverse_iterator<const T *> rbegin() const
{
return std::reverse_iterator<T *>(this->end());
}
std::reverse_iterator<const T *> rend() const
{
return std::reverse_iterator<T *>(this->begin());
}
/**
* Get an index range containing all valid indices for this array.
*/
IndexRange index_range() const
{
return IndexRange(size_);
}
/**
* Sets the size to zero. This should only be used when you have manually destructed all elements
* in the array beforehand. Use with care.
*/
void clear_without_destruct()
{
size_ = 0;
}
/**
* Access the allocator used by this array.
*/
Allocator &allocator()
{
return allocator_;
}
/**
* Get the value of the InlineBufferCapacity template argument. This is the number of elements
* that can be stored without doing an allocation.
*/
static int64_t inline_buffer_capacity()
{
return InlineBufferCapacity;
}
private:
T *get_buffer_for_size(int64_t size)
{
if (size <= InlineBufferCapacity) {
return inline_buffer_;
}
else {
return this->allocate(size);
}
}
T *allocate(int64_t size)
{
return static_cast<T *>(
allocator_.allocate(static_cast<size_t>(size) * sizeof(T), alignof(T), AT));
}
bool uses_inline_buffer() const
{
return data_ == inline_buffer_;
}
};
/**
* Same as a normal Array, but does not use Blender's guarded allocator. This is useful when
* allocating memory with static storage duration.
*/
template<typename T, int64_t InlineBufferCapacity = default_inline_buffer_capacity(sizeof(T))>
using RawArray = Array<T, InlineBufferCapacity, RawAllocator>;
} // namespace blender
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