#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 . */ #ifndef BLT_GP_STACK_H #define BLT_GP_STACK_H #include #include #include #include #include #include #include #include #include #include #include #include namespace blt::gp { class stack_allocator { constexpr static blt::size_t PAGE_SIZE = 0x1000; constexpr static blt::size_t MAX_ALIGNMENT = 8; template using NO_REF_T = std::remove_cv_t>; 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 total_dealloc = 0; blt::size_t total_dealloc_used = 0; blt::size_t total_dealloc_remaining = 0; blt::size_t total_dealloc_no_meta = 0; blt::size_t blocks = 0; friend std::ostream& operator<<(std::ostream& stream, const size_data_t& data) { stream << "["; stream << data.total_used_bytes << "/"; stream << data.total_size_bytes << "("; stream << (static_cast(data.total_used_bytes) / static_cast(data.total_size_bytes) * 100) << "%), "; stream << data.total_used_bytes << "/"; stream << data.total_no_meta_bytes << "("; stream << (static_cast(data.total_used_bytes) / static_cast(data.total_no_meta_bytes) * 100) << "%), (empty space: "; stream << data.total_remaining_bytes << ") blocks: " << data.blocks << " || unallocated space: "; stream << data.total_dealloc_used << "/"; stream << data.total_dealloc; if (static_cast(data.total_dealloc) > 0) stream << "(" << (static_cast(data.total_dealloc_used) / static_cast(data.total_dealloc) * 100) << "%)"; stream << ", "; stream << data.total_dealloc_used << "/"; stream << data.total_dealloc_no_meta; if (data.total_dealloc_no_meta > 0) stream << "(" << (static_cast(data.total_dealloc_used) / static_cast(data.total_dealloc_no_meta * 100)) << "%)"; stream << ", (empty space: " << data.total_dealloc_remaining << ")]"; return stream; } }; /** * 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 void push(T&& value) { using NO_REF_T = std::remove_cv_t>; static_assert(std::is_trivially_copyable_v && "Type must be bitwise copyable!"); static_assert(alignof(NO_REF_T) <= MAX_ALIGNMENT && "Type must not be greater than the max alignment!"); auto ptr = allocate_bytes(); head->metadata.offset = static_cast(ptr) + aligned_size(); new(ptr) NO_REF_T(std::forward(value)); } template T pop() { using NO_REF_T = std::remove_cv_t>; static_assert(std::is_trivially_copyable_v && "Type must be bitwise copyable!"); constexpr static auto TYPE_SIZE = aligned_size(); while (head->used_bytes_in_block() == 0 && move_back()); if (empty()) throw std::runtime_error("Silly boi the stack is empty!"); if (head->used_bytes_in_block() < static_cast(aligned_size())) 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(NO_REF_T))).c_str()); // make copy NO_REF_T t = *reinterpret_cast(head->metadata.offset - TYPE_SIZE); // call destructor reinterpret_cast(head->metadata.offset - TYPE_SIZE)->~NO_REF_T(); // move offset back head->metadata.offset -= TYPE_SIZE; return t; } template T& from(blt::size_t bytes) { using NO_REF_T = std::remove_cv_t>; constexpr static auto TYPE_SIZE = aligned_size(); auto remaining_bytes = static_cast(bytes + TYPE_SIZE); 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; if (bytes_available < 0) { remaining_bytes -= blk->used_bytes_in_block(); 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(TYPE_SIZE)) 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(NO_REF_T))).c_str()); return *reinterpret_cast(blk->metadata.offset - remaining_bytes); } 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) { while (head->used_bytes_in_block() == 0 && move_back()); if (empty()) throw std::runtime_error("This stack is empty!"); auto type_size = aligned_size(bytes); if (head->used_bytes_in_block() < static_cast(type_size)) BLT_ABORT(("This stack doesn't contain enough data for this type! " + std::to_string(head->used_bytes_in_block()) + " / " + std::to_string(bytes) + " This is an invalid runtime state!").c_str()); auto ptr = to.allocate_bytes(type_size); to.head->metadata.offset = static_cast(ptr) + type_size; std::memcpy(ptr, head->metadata.offset - type_size, type_size); head->metadata.offset -= type_size; } template void call_destructors() { blt::size_t offset = 0; ((from>(offset).~NO_REF_T(), offset += stack_allocator::aligned_size> ()), ...); } [[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* prev = head; while (prev != nullptr) { size_data.total_size_bytes += prev->metadata.size; size_data.total_no_meta_bytes += prev->storage_size(); size_data.total_remaining_bytes += prev->remaining_bytes_in_block(); size_data.total_used_bytes += prev->used_bytes_in_block(); size_data.blocks++; prev = prev->metadata.prev; } if (head != nullptr) { auto next = head->metadata.next; while (next != nullptr) { size_data.total_dealloc += next->metadata.size; size_data.total_dealloc_no_meta += next->storage_size(); size_data.total_dealloc_remaining += next->remaining_bytes_in_block(); size_data.total_dealloc_used += 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() { if (head != nullptr) { auto blk = head->metadata.next; while (blk != nullptr) { auto ptr = blk; blk = blk->metadata.next; std::free(ptr); } } free_chain(head); } template static inline constexpr blt::size_t aligned_size() noexcept { return aligned_size(sizeof(NO_REF_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(metadata.size - sizeof(typename block::block_metadata_t)); } [[nodiscard]] blt::ptrdiff_t used_bytes_in_block() const { return static_cast(metadata.offset - buffer); } [[nodiscard]] blt::ptrdiff_t remaining_bytes_in_block() const { return storage_size() - used_bytes_in_block(); } }; template void* allocate_bytes() { return allocate_bytes(sizeof(NO_REF_T)); } void* allocate_bytes(blt::size_t size) { auto ptr = get_aligned_pointer(size); if (ptr == nullptr) { while (head != nullptr && head->metadata.next != nullptr) { head = head->metadata.next; if (head != nullptr) head->reset(); if (head->remaining_bytes_in_block() >= static_cast(size)) break; } if (head == nullptr || head->remaining_bytes_in_block() < static_cast(size)) push_block(aligned_size(size) + sizeof(typename block::block_metadata_t)); } 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(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); //auto* data = get_allocator().allocate(size); new(data) block{size}; return reinterpret_cast(data); } static void free_chain(block* current) { while (current != nullptr) { block* ptr = current; current = current->metadata.prev; std::free(ptr); //get_allocator().deallocate(ptr); } } inline bool move_back() { auto old = head; head = head->metadata.prev; if (head == nullptr) { head = old; return false; } return true; //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