419 lines
16 KiB
C++
419 lines
16 KiB
C++
#pragma once
|
|
/*
|
|
* Copyright (C) 2024 Brett Terpstra
|
|
*
|
|
* 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 3 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, see <https://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
#ifndef BLT_GP_STACK_H
|
|
#define BLT_GP_STACK_H
|
|
|
|
#include <blt/std/types.h>
|
|
#include <blt/std/assert.h>
|
|
#include <blt/std/logging.h>
|
|
#include <blt/gp/fwdecl.h>
|
|
#include <utility>
|
|
#include <stdexcept>
|
|
#include <cstdlib>
|
|
#include <memory>
|
|
#include <type_traits>
|
|
#include <cstring>
|
|
|
|
namespace blt::gp
|
|
{
|
|
class stack_allocator
|
|
{
|
|
constexpr static blt::size_t PAGE_SIZE = 0x1000;
|
|
constexpr static blt::size_t MAX_ALIGNMENT = 8;
|
|
public:
|
|
struct size_data_t
|
|
{
|
|
blt::size_t total_size_bytes = 0;
|
|
blt::size_t total_used_bytes = 0;
|
|
blt::size_t total_remaining_bytes = 0;
|
|
blt::size_t total_no_meta_bytes = 0;
|
|
blt::size_t blocks = 0;
|
|
};
|
|
|
|
|
|
/**
|
|
* Pushes an instance of an object on to the stack
|
|
* @tparam T type to push
|
|
* @param value universal reference to the object to push
|
|
*/
|
|
template<typename T>
|
|
void push(T&& value)
|
|
{
|
|
using NO_REF_T = std::remove_reference_t<T>;
|
|
static_assert(std::is_trivially_copyable_v<NO_REF_T> && "Type must be bitwise copyable!");
|
|
auto ptr = allocate_bytes<T>();
|
|
head->metadata.offset = static_cast<blt::u8*>(ptr) + aligned_size<T>();
|
|
new(ptr) NO_REF_T(std::forward<T>(value));
|
|
}
|
|
|
|
template<typename T>
|
|
T pop()
|
|
{
|
|
using NO_REF_T = std::remove_reference_t<T>;
|
|
static_assert(std::is_trivially_copyable_v<NO_REF_T> && "Type must be bitwise copyable!");
|
|
constexpr static auto TYPE_SIZE = aligned_size<T>();
|
|
if (head == nullptr)
|
|
throw std::runtime_error("Silly boi the stack is empty!");
|
|
if (head->used_bytes_in_block() < static_cast<blt::ptrdiff_t>(aligned_size<T>()))
|
|
throw std::runtime_error((std::string("Mismatched Types! Not enough space left in block! Bytes: ") += std::to_string(
|
|
head->used_bytes_in_block()) += " Size: " + std::to_string(sizeof(T))).c_str());
|
|
if (head->used_bytes_in_block() == 0)
|
|
move_back();
|
|
// make copy
|
|
T t = *reinterpret_cast<T*>(head->metadata.offset - TYPE_SIZE);
|
|
// call destructor
|
|
reinterpret_cast<T*>(head->metadata.offset - TYPE_SIZE)->~T();
|
|
// move offset back
|
|
head->metadata.offset -= TYPE_SIZE;
|
|
return t;
|
|
}
|
|
|
|
template<typename T>
|
|
T& from(blt::size_t bytes)
|
|
{
|
|
constexpr static auto TYPE_SIZE = aligned_size<T>();
|
|
auto remaining_bytes = static_cast<blt::i64>(bytes);
|
|
blt::i64 bytes_into_block = 0;
|
|
block* blk = head;
|
|
while (remaining_bytes > 0)
|
|
{
|
|
if (blk == nullptr)
|
|
throw std::runtime_error("Requested size is beyond the scope of this stack!");
|
|
auto bytes_available = blk->used_bytes_in_block() - remaining_bytes;
|
|
bytes_into_block = remaining_bytes;
|
|
if (bytes_available < 0)
|
|
{
|
|
remaining_bytes = -bytes_available;
|
|
blk = head->metadata.prev;
|
|
} else
|
|
break;
|
|
}
|
|
if (blk == nullptr)
|
|
throw std::runtime_error("Some nonsense is going on. This function already smells");
|
|
if (blk->used_bytes_in_block() < static_cast<blt::ptrdiff_t>(aligned_size<T>()))
|
|
throw std::runtime_error((std::string("Mismatched Types! Not enough space left in block! Bytes: ") += std::to_string(
|
|
blk->used_bytes_in_block()) += " Size: " + std::to_string(sizeof(T))).c_str());
|
|
return *reinterpret_cast<T*>((blk->metadata.offset - bytes_into_block) - TYPE_SIZE);
|
|
}
|
|
|
|
void pop_bytes(blt::ptrdiff_t bytes)
|
|
{
|
|
#if BLT_DEBUG_LEVEL >= 3
|
|
blt::size_t counter = 0;
|
|
#endif
|
|
while (bytes > 0)
|
|
{
|
|
#if BLT_DEBUG_LEVEL > 0
|
|
if (head == nullptr)
|
|
{
|
|
BLT_WARN("Head is nullptr, unable to pop bytes!");
|
|
BLT_WARN("This error is normally caused by an invalid tree!");
|
|
#if BLT_DEBUG_LEVEL >= 3
|
|
BLT_WARN("Made it to %ld iterations", counter);
|
|
#endif
|
|
return;
|
|
}
|
|
#if BLT_DEBUG_LEVEL >= 3
|
|
counter++;
|
|
#endif
|
|
#endif
|
|
auto diff = head->used_bytes_in_block() - bytes;
|
|
// if there is not enough room left to pop completely off the block, then move to the next previous block
|
|
// and pop from it, update the amount of bytes to reflect the amount removed from the current block
|
|
if (diff <= 0)
|
|
{
|
|
bytes -= head->used_bytes_in_block();
|
|
if (diff == 0)
|
|
break;
|
|
move_back();
|
|
} else
|
|
{
|
|
// otherwise update the offset pointer
|
|
head->metadata.offset -= bytes;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Warning this function should be used to transfer types, not arrays of types! It will produce an error if you attempt to pass more
|
|
* than one type # of bytes at a time~!
|
|
* @param to stack to push to
|
|
* @param bytes number of bytes to transfer out.
|
|
*/
|
|
void transfer_bytes(stack_allocator& to, blt::size_t bytes)
|
|
{
|
|
if (empty())
|
|
throw std::runtime_error("This stack is empty!");
|
|
if (head->used_bytes_in_block() < static_cast<blt::ptrdiff_t>(bytes))
|
|
BLT_ABORT("This stack doesn't contain enough data for this type! This is an invalid runtime state!");
|
|
|
|
if (head->used_bytes_in_block() == 0)
|
|
move_back();
|
|
|
|
auto type_size = aligned_size(bytes);
|
|
auto ptr = to.allocate_bytes(bytes);
|
|
to.head->metadata.offset = static_cast<blt::u8*>(ptr) + type_size;
|
|
std::memcpy(ptr, head->metadata.offset - type_size, type_size);
|
|
head->metadata.offset -= type_size;
|
|
}
|
|
|
|
template<typename... Args>
|
|
void call_destructors()
|
|
{
|
|
blt::size_t offset = 0;
|
|
((from<Args>(offset).~Args(), offset += stack_allocator::aligned_size<Args>()), ...);
|
|
}
|
|
|
|
[[nodiscard]] bool empty() const
|
|
{
|
|
if (head == nullptr)
|
|
return true;
|
|
if (head->metadata.prev != nullptr)
|
|
return false;
|
|
return head->used_bytes_in_block() == 0;
|
|
}
|
|
|
|
[[nodiscard]] blt::ptrdiff_t bytes_in_head() const
|
|
{
|
|
if (head == nullptr)
|
|
return 0;
|
|
return head->used_bytes_in_block();
|
|
}
|
|
|
|
/**
|
|
* Warning this function is slow!
|
|
* @return the size of the stack allocator in bytes
|
|
*/
|
|
[[nodiscard]] size_data_t size()
|
|
{
|
|
size_data_t size_data;
|
|
auto* next = head;
|
|
while (next != nullptr)
|
|
{
|
|
size_data.total_size_bytes += next->metadata.size;
|
|
size_data.total_no_meta_bytes += next->storage_size();
|
|
size_data.total_remaining_bytes += next->remaining_bytes_in_block();
|
|
size_data.total_used_bytes += next->used_bytes_in_block();
|
|
size_data.blocks++;
|
|
next = next->metadata.next;
|
|
}
|
|
return size_data;
|
|
}
|
|
|
|
stack_allocator() = default;
|
|
|
|
// TODO: cleanup this allocator!
|
|
// if you keep track of type size information you can memcpy between stack allocators as you already only allow trivially copyable types
|
|
stack_allocator(const stack_allocator& copy)
|
|
{
|
|
if (copy.empty())
|
|
return;
|
|
|
|
head = nullptr;
|
|
block* list_itr = nullptr;
|
|
|
|
// start at the beginning of the list
|
|
block* current = copy.head;
|
|
while (current != nullptr)
|
|
{
|
|
list_itr = current;
|
|
current = current->metadata.prev;
|
|
}
|
|
// copy all the blocks
|
|
while (list_itr != nullptr)
|
|
{
|
|
push_block(list_itr->metadata.size);
|
|
std::memcpy(head->buffer, list_itr->buffer, list_itr->storage_size());
|
|
head->metadata.size = list_itr->metadata.size;
|
|
head->metadata.offset = head->buffer + list_itr->used_bytes_in_block();
|
|
list_itr = list_itr->metadata.next;
|
|
}
|
|
}
|
|
|
|
stack_allocator& operator=(const stack_allocator& copy) = delete;
|
|
|
|
stack_allocator(stack_allocator&& move) noexcept
|
|
{
|
|
head = move.head;
|
|
move.head = nullptr;
|
|
}
|
|
|
|
stack_allocator& operator=(stack_allocator&& move) noexcept
|
|
{
|
|
move.head = std::exchange(head, move.head);
|
|
return *this;
|
|
}
|
|
|
|
~stack_allocator()
|
|
{
|
|
free_chain(head);
|
|
}
|
|
|
|
template<typename T>
|
|
static inline constexpr blt::size_t aligned_size() noexcept
|
|
{
|
|
return aligned_size(sizeof(T));
|
|
}
|
|
|
|
static inline constexpr blt::size_t aligned_size(blt::size_t size) noexcept
|
|
{
|
|
return (size + (MAX_ALIGNMENT - 1)) & ~(MAX_ALIGNMENT - 1);
|
|
}
|
|
|
|
private:
|
|
struct block
|
|
{
|
|
struct block_metadata_t
|
|
{
|
|
blt::size_t size = 0;
|
|
block* next = nullptr;
|
|
block* prev = nullptr;
|
|
blt::u8* offset = nullptr;
|
|
} metadata;
|
|
blt::u8 buffer[8]{};
|
|
|
|
explicit block(blt::size_t size)
|
|
{
|
|
#if BLT_DEBUG_LEVEL > 0
|
|
if (size < PAGE_SIZE)
|
|
{
|
|
BLT_WARN("Hey this block is too small, who allocated it?");
|
|
std::abort();
|
|
}
|
|
#endif
|
|
metadata.size = size;
|
|
metadata.offset = buffer;
|
|
}
|
|
|
|
void reset()
|
|
{
|
|
metadata.offset = buffer;
|
|
}
|
|
|
|
[[nodiscard]] blt::ptrdiff_t storage_size() const
|
|
{
|
|
return static_cast<blt::ptrdiff_t>(metadata.size - sizeof(typename block::block_metadata_t));
|
|
}
|
|
|
|
[[nodiscard]] blt::ptrdiff_t used_bytes_in_block() const
|
|
{
|
|
return static_cast<blt::ptrdiff_t>(metadata.offset - buffer);
|
|
}
|
|
|
|
[[nodiscard]] blt::ptrdiff_t remaining_bytes_in_block() const
|
|
{
|
|
return storage_size() - used_bytes_in_block();
|
|
}
|
|
};
|
|
|
|
template<typename T>
|
|
void* allocate_bytes()
|
|
{
|
|
return allocate_bytes(sizeof(T));
|
|
}
|
|
|
|
void* allocate_bytes(blt::size_t size)
|
|
{
|
|
auto ptr = get_aligned_pointer(size);
|
|
if (ptr == nullptr)
|
|
{
|
|
if (head != nullptr && head->metadata.next != nullptr)
|
|
{
|
|
head = head->metadata.next;
|
|
if (head != nullptr)
|
|
head->reset();
|
|
} else
|
|
push_block(aligned_size(size));
|
|
}
|
|
ptr = get_aligned_pointer(size);
|
|
if (ptr == nullptr)
|
|
throw std::bad_alloc();
|
|
return ptr;
|
|
}
|
|
|
|
void* get_aligned_pointer(blt::size_t bytes)
|
|
{
|
|
if (head == nullptr)
|
|
return nullptr;
|
|
blt::size_t remaining_bytes = head->remaining_bytes_in_block();
|
|
auto* pointer = static_cast<void*>(head->metadata.offset);
|
|
return std::align(MAX_ALIGNMENT, bytes, pointer, remaining_bytes);
|
|
}
|
|
|
|
void push_block(blt::size_t size)
|
|
{
|
|
auto blk = allocate_block(size);
|
|
if (head == nullptr)
|
|
{
|
|
head = blk;
|
|
return;
|
|
}
|
|
head->metadata.next = blk;
|
|
blk->metadata.prev = head;
|
|
head = blk;
|
|
}
|
|
|
|
static size_t to_nearest_page_size(blt::size_t bytes)
|
|
{
|
|
constexpr static blt::size_t MASK = ~(PAGE_SIZE - 1);
|
|
return (bytes & MASK) + PAGE_SIZE;
|
|
}
|
|
|
|
static block* allocate_block(blt::size_t bytes)
|
|
{
|
|
auto size = to_nearest_page_size(bytes);
|
|
auto* data = std::aligned_alloc(PAGE_SIZE, size);
|
|
new(data) block{size};
|
|
return reinterpret_cast<block*>(data);
|
|
}
|
|
|
|
static void free_chain(block* current)
|
|
{
|
|
while (current != nullptr)
|
|
{
|
|
block* ptr = current;
|
|
current = current->metadata.prev;
|
|
std::free(ptr);
|
|
}
|
|
}
|
|
|
|
inline void move_back()
|
|
{
|
|
auto old = head;
|
|
head = head->metadata.prev;
|
|
if (head == nullptr)
|
|
{
|
|
head = old;
|
|
head->reset();
|
|
}
|
|
//free_chain(old);
|
|
// required to prevent silly memory :3
|
|
// if (head != nullptr)
|
|
// head->metadata.next = nullptr;
|
|
// std::free(old);
|
|
}
|
|
|
|
private:
|
|
block* head = nullptr;
|
|
};
|
|
}
|
|
|
|
#endif //BLT_GP_STACK_H
|