330 lines
13 KiB
C++
330 lines
13 KiB
C++
#pragma once
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/*
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* Copyright (C) 2024 Brett Terpstra
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <https://www.gnu.org/licenses/>.
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*/
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#ifndef BLT_GP_STACK_H
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#define BLT_GP_STACK_H
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#include <blt/std/types.h>
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#include <blt/std/assert.h>
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#include <blt/std/logging.h>
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#include <blt/std/allocator.h>
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#include <blt/std/ranges.h>
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#include <blt/std/meta.h>
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#include <blt/gp/fwdecl.h>
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#include <utility>
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#include <stdexcept>
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#include <cstdlib>
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#include <memory>
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#include <type_traits>
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#include <cstring>
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#include <iostream>
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namespace blt::gp
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{
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namespace detail
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{
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BLT_META_MAKE_FUNCTION_CHECK(drop);
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}
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class stack_allocator
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{
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constexpr static blt::size_t PAGE_SIZE = 0x1000;
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constexpr static blt::size_t MAX_ALIGNMENT = 8;
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template<typename T>
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using NO_REF_T = std::remove_cv_t<std::remove_reference_t<T>>;
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public:
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struct size_data_t
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{
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blt::size_t total_size_bytes = 0;
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blt::size_t total_used_bytes = 0;
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blt::size_t total_remaining_bytes = 0;
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friend std::ostream& operator<<(std::ostream& stream, const size_data_t& data)
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{
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stream << "[";
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stream << data.total_used_bytes << " / " << data.total_size_bytes;
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stream << " ("
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<< (data.total_size_bytes != 0 ? (static_cast<double>(data.total_used_bytes) / static_cast<double>(data.total_size_bytes) *
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100) : 0) << "%); space left: " << data.total_remaining_bytes << "]";
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return stream;
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}
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};
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template<typename T>
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static inline constexpr blt::size_t aligned_size() noexcept
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{
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return aligned_size(sizeof(NO_REF_T<T>));
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}
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static inline constexpr blt::size_t aligned_size(blt::size_t size) noexcept
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{
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return (size + (MAX_ALIGNMENT - 1)) & ~(MAX_ALIGNMENT - 1);
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}
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stack_allocator() = default;
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stack_allocator(const stack_allocator& copy)
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{
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if (copy.data_ == nullptr || copy.bytes_stored == 0)
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return;
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expand(copy.size_);
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std::memcpy(data_, copy.data_, copy.bytes_stored);
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bytes_stored = copy.bytes_stored;
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}
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stack_allocator(stack_allocator&& move) noexcept:
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data_(std::exchange(move.data_, nullptr)), bytes_stored(move.bytes_stored), size_(move.size_)
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{}
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stack_allocator& operator=(const stack_allocator& copy) = delete;
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stack_allocator& operator=(stack_allocator&& move) noexcept
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{
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data_ = std::exchange(move.data_, data_);
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size_ = std::exchange(move.size_, size_);
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bytes_stored = std::exchange(move.bytes_stored, bytes_stored);
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return *this;
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}
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~stack_allocator()
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{
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std::free(data_);
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}
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void insert(const stack_allocator& stack)
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{
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#if BLT_DEBUG_LEVEL > 1
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if (stack.empty())
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BLT_WARN("Insert called on an empty stack!");
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#endif
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if (size_ < stack.bytes_stored + bytes_stored)
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expand(stack.bytes_stored + bytes_stored);
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std::memcpy(data_ + bytes_stored, stack.data_, stack.bytes_stored);
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bytes_stored += stack.bytes_stored;
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}
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void copy_from(const stack_allocator& stack, blt::size_t bytes)
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{
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#if BLT_DEBUG_LEVEL > 0
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if (stack.empty())
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BLT_WARN("Copy From called on an empty stack");
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if (bytes == 0)
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BLT_WARN("Requested 0 bytes to be copied. This seems to be an error!");
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#endif
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if (size_ < bytes + bytes_stored)
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expand(bytes + bytes_stored);
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std::memcpy(data_ + bytes_stored, stack.data_ + (stack.bytes_stored - bytes), bytes);
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bytes_stored += bytes;
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}
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void copy_from(blt::u8* data, blt::size_t bytes)
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{
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#if BLT_DEBUG_LEVEL > 0
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if (data == nullptr)
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BLT_ABORT("Nullptr provided to copy_from function!");
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if (bytes == 0)
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BLT_WARN("Requested 0 bytes to be copied from, nothing will happen.");
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#endif
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if (size_ < bytes + bytes_stored)
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expand(bytes + bytes_stored);
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std::memcpy(data_ + bytes_stored, data, bytes);
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bytes_stored += bytes;
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}
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void copy_to(blt::u8* data, blt::size_t bytes)
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{
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#if BLT_DEBUG_LEVEL > 0
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if (data == nullptr)
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BLT_ABORT("Nullptr provided to copy_to function!");
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if (bytes == 0)
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BLT_WARN("Requested 0 to be copied to, nothing will happen!");
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#endif
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std::memcpy(data, data_ + (bytes_stored - bytes), bytes);
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}
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template<typename T, typename NO_REF = NO_REF_T<T>>
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void push(const T& t)
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{
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static_assert(std::is_trivially_copyable_v<NO_REF> && "Type must be bitwise copyable!");
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static_assert(alignof(NO_REF) <= MAX_ALIGNMENT && "Type alignment must not be greater than the max alignment!");
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auto ptr = allocate_bytes_for_size(sizeof(NO_REF));
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std::memcpy(ptr, &t, sizeof(NO_REF));
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}
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template<typename T, typename NO_REF = NO_REF_T<T>>
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T pop()
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{
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static_assert(std::is_trivially_copyable_v<NO_REF> && "Type must be bitwise copyable!");
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static_assert(alignof(NO_REF) <= MAX_ALIGNMENT && "Type alignment must not be greater than the max alignment!");
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constexpr auto size = aligned_size(sizeof(NO_REF));
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#if BLT_DEBUG_LEVEL > 0
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if (bytes_stored < size)
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BLT_ABORT("Not enough bytes left to pop!");
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#endif
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bytes_stored -= size;
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return *reinterpret_cast<T*>(data_ + bytes_stored);
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}
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template<typename T, typename NO_REF = NO_REF_T<T>>
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T& from(blt::size_t bytes)
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{
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static_assert(std::is_trivially_copyable_v<NO_REF> && "Type must be bitwise copyable!");
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static_assert(alignof(NO_REF) <= MAX_ALIGNMENT && "Type alignment must not be greater than the max alignment!");
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auto size = aligned_size(sizeof(NO_REF)) + bytes;
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#if BLT_DEBUG_LEVEL > 0
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if (bytes_stored < size)
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BLT_ABORT(("Not enough bytes in stack to reference " + std::to_string(size) + " bytes requested but " + std::to_string(bytes) +
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" bytes stored!").c_str());
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#endif
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return *reinterpret_cast<NO_REF*>(data_ + bytes_stored - size);
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}
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void pop_bytes(blt::size_t bytes)
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{
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#if BLT_DEBUG_LEVEL > 0
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if (bytes_stored < bytes)
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BLT_ABORT(("Not enough bytes in stack to pop " + std::to_string(bytes) + " bytes requested but " + std::to_string(bytes) +
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" bytes stored!").c_str());
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#endif
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bytes_stored -= bytes;
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}
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void transfer_bytes(stack_allocator& to, blt::size_t bytes)
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{
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#if BLT_DEBUG_LEVEL > 0
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if (bytes_stored < bytes)
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BLT_ABORT(("Not enough bytes in stack to transfer " + std::to_string(bytes) + " bytes requested but " + std::to_string(bytes) +
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" bytes stored!").c_str());
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#endif
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to.copy_from(*this, aligned_size(bytes));
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pop_bytes(bytes);
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}
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template<typename... Args>
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void call_destructors(detail::bitmask_t* mask)
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{
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if constexpr (sizeof...(Args) > 0)
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{
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blt::size_t offset = (stack_allocator::aligned_size(sizeof(NO_REF_T<Args>)) + ...) -
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stack_allocator::aligned_size(sizeof(NO_REF_T<typename blt::meta::arg_helper<Args...>::First>));
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blt::size_t index = 0;
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if (mask != nullptr)
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index = mask->size() - sizeof...(Args);
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((call_drop<Args>(offset, index, mask), offset -= stack_allocator::aligned_size(sizeof(NO_REF_T<Args>)), ++index), ...);
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if (mask != nullptr)
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{
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auto& mask_r = *mask;
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for (blt::size_t i = 0; i < sizeof...(Args); i++)
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mask_r.pop_back();
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}
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}
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}
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[[nodiscard]] bool empty() const noexcept
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{
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return bytes_stored == 0;
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}
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[[nodiscard]] blt::ptrdiff_t remaining_bytes_in_block() const noexcept
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{
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return static_cast<blt::ptrdiff_t>(size_ - bytes_stored);
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}
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[[nodiscard]] blt::ptrdiff_t bytes_in_head() const noexcept
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{
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return static_cast<blt::ptrdiff_t>(bytes_stored);
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}
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[[nodiscard]] size_data_t size() const noexcept
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{
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size_data_t data;
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data.total_used_bytes = bytes_stored;
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data.total_size_bytes = size_;
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data.total_remaining_bytes = remaining_bytes_in_block();
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return data;
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}
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private:
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void expand(blt::size_t bytes)
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{
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bytes = to_nearest_page_size(bytes);
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auto new_data = static_cast<blt::u8*>(std::malloc(bytes));
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if (bytes_stored > 0)
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std::memcpy(new_data, data_, bytes_stored);
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std::free(data_);
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data_ = new_data;
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size_ = bytes;
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}
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static size_t to_nearest_page_size(blt::size_t bytes) noexcept
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{
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constexpr static blt::size_t MASK = ~(PAGE_SIZE - 1);
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return (bytes & MASK) + PAGE_SIZE;
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}
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void* get_aligned_pointer(blt::size_t bytes) noexcept
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{
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if (data_ == nullptr)
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return nullptr;
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blt::size_t remaining_bytes = remaining_bytes_in_block();
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auto* pointer = static_cast<void*>(data_ + bytes_stored);
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return std::align(MAX_ALIGNMENT, bytes, pointer, remaining_bytes);
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}
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void* allocate_bytes_for_size(blt::size_t bytes)
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{
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auto aligned_ptr = get_aligned_pointer(bytes);
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if (aligned_ptr == nullptr)
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{
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expand(bytes + MAX_ALIGNMENT);
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aligned_ptr = get_aligned_pointer(bytes);
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}
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if (aligned_ptr == nullptr)
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throw std::bad_alloc();
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auto used_bytes = aligned_size(bytes);
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bytes_stored += used_bytes;
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return aligned_ptr;
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}
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template<typename T>
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inline void call_drop(blt::size_t offset, blt::size_t index, detail::bitmask_t* mask)
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{
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if constexpr (detail::has_func_drop_v<T>)
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{
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if (mask != nullptr)
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{
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auto& mask_r = *mask;
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if (!mask_r[index])
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return;
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}
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from<NO_REF_T<T >>(offset).drop();
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}
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}
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blt::u8* data_ = nullptr;
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// place in the data_ array which has a free spot.
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blt::size_t bytes_stored = 0;
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blt::size_t size_ = 0;
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};
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}
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#endif //BLT_GP_STACK_H
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