From b3b1385e7af85ba2cb1f92bc31706099f1b9d562 Mon Sep 17 00:00:00 2001
From: Aqua-sama <aqua@iserlohn-fortress.net>
Date: Sun, 28 Mar 2021 12:41:57 +0300
Subject: Move MemoryAllocator to libk

---
 src/allocator.cc | 90 --------------------------------------------------------
 src/allocator.h  | 39 ------------------------
 src/kernel.cc    |  3 +-
 src/makefile     |  1 -
 4 files changed, 1 insertion(+), 132 deletions(-)
 delete mode 100644 src/allocator.cc
 delete mode 100644 src/allocator.h

(limited to 'src')

diff --git a/src/allocator.cc b/src/allocator.cc
deleted file mode 100644
index 77736cc..0000000
--- a/src/allocator.cc
+++ /dev/null
@@ -1,90 +0,0 @@
-#include "allocator.h"
-
-static MemoryAllocator* mem_alloc = nullptr;
-
-MemoryAllocator::MemoryAllocator(uint32_t start, size_t size) {
-  if (size < sizeof(MemoryChunk)) {
-    begin = nullptr;
-    return;
-  }
-  begin = new (reinterpret_cast<void*>(start)) MemoryChunk{.size = static_cast<size_t>(size - sizeof(MemoryChunk))};
-  if (mem_alloc == nullptr) mem_alloc = this;
-}
-
-void* MemoryAllocator::malloc(size_t size) {
-  // TODO spinlock
-  // TODO memset 0 over allocated memory
-  MemoryChunk* result = nullptr;
-
-  // find the first chunk that is at least size and not allocated
-  for (auto* iter = begin; iter != nullptr; iter = iter->next) {
-    if (iter->size >= size && !iter->allocated) {
-      result = iter;
-
-      // split chunk if there is at least one byte left over
-      if (result->size >= size + sizeof(MemoryChunk) + 1) {
-        auto* _new = new (result + sizeof(MemoryChunk) + size) MemoryChunk{
-            .prev = result, .next = result->next, .size = static_cast<size_t>(result->size - sizeof(MemoryChunk))};
-        result->next = _new;
-      }
-
-      break;
-    }
-  }
-
-  return result + sizeof(MemoryChunk);
-}
-void MemoryAllocator::free(void* ptr) {
-  auto* chunk = reinterpret_cast<MemoryChunk*>(reinterpret_cast<uint32_t>(ptr) - sizeof(MemoryChunk));
-  chunk->allocated = false;
-
-  // merge in next chunk
-  if (chunk->next != nullptr && !chunk->next->allocated) {
-    chunk->size += chunk->next->size + sizeof(MemoryChunk);
-    chunk->next = chunk->next->next;
-    if (chunk->next != nullptr) chunk->next->prev = chunk;
-  }
-
-  // merge into previous chunk
-  if (chunk->prev != nullptr && !chunk->prev->allocated) {
-    chunk->prev->size += chunk->size + sizeof(MemoryChunk);
-    chunk->prev->next = chunk->next;
-    if (chunk->next != nullptr) chunk->next->prev = chunk->prev;
-  }
-};
-
-size_t MemoryAllocator::free_space() const {
-  size_t r = 0;
-  for (auto* iter = begin; iter != nullptr; iter = iter->next)
-    if (!iter->allocated) r += iter->size;
-  return r;
-}
-size_t MemoryAllocator::used_space() const {
-  size_t r = 0;
-  for (auto* iter = begin; iter != nullptr; iter = iter->next)
-    if (iter->allocated) r += iter->size;
-  return r;
-}
-
-void* operator new(unsigned sz, const std::nothrow_t&) noexcept {
-  if (mem_alloc == nullptr) return nullptr;
-  return mem_alloc->malloc(sz);
-}
-void* operator new[](unsigned sz, const std::nothrow_t&) noexcept {
-  if (mem_alloc == nullptr) return nullptr;
-  return mem_alloc->malloc(sz);
-}
-
-void operator delete(void* ptr) {
-  if (mem_alloc != nullptr) mem_alloc->free(ptr);
-}
-void operator delete[](void* ptr) {
-  if (mem_alloc != nullptr) mem_alloc->free(ptr);
-}
-
-void* operator new(unsigned /* size_bytes */, void* ptr) {
-  return ptr;
-}
-void* operator new[](unsigned /* size_bytes */, void* ptr) {
-  return ptr;
-}
diff --git a/src/allocator.h b/src/allocator.h
deleted file mode 100644
index 8a12be8..0000000
--- a/src/allocator.h
+++ /dev/null
@@ -1,39 +0,0 @@
-#pragma once
-
-#include <types.h>
-
-class MemoryAllocator {
-public:
-  MemoryAllocator(uint32_t start, size_t size);
-
-  void* malloc(size_t size);
-  void free(void* ptr);
-
-  size_t free_space() const;
-  size_t used_space() const;
-
-private:
-  struct MemoryChunk {
-    MemoryChunk* prev = nullptr;
-    MemoryChunk* next = nullptr;
-    bool allocated = false;
-    size_t size = 0;
-  };
-  MemoryChunk* begin;
-};
-
-namespace std {
-struct nothrow_t {
-  explicit nothrow_t() = default;
-};
-};  // namespace std
-
-void* operator new(unsigned, const std::nothrow_t&) noexcept;
-void* operator new[](unsigned, const std::nothrow_t&) noexcept;
-
-void operator delete(void* ptr);
-void operator delete[](void* ptr);
-
-// placement new
-void* operator new(unsigned, void*);
-void* operator new[](unsigned, void*);
diff --git a/src/kernel.cc b/src/kernel.cc
index 578344c..fc02f5b 100644
--- a/src/kernel.cc
+++ b/src/kernel.cc
@@ -8,9 +8,8 @@
 #error "This tutorial needs to be compiled with a ix86-elf compiler"
 #endif
 
+#include <memory.h>
 #include <stdlib.h>
-#include <types.h>
-#include "allocator.h"
 #include "cga.h"
 #include "cpu/cpu.h"
 #include "gdt.h"
diff --git a/src/makefile b/src/makefile
index 1d85f4b..d1e2147 100644
--- a/src/makefile
+++ b/src/makefile
@@ -9,7 +9,6 @@ CXX_OBJ = kernel.o \
 	  idt.o \
 	  idt/exception.o idt/interruptgate.o idt/interrupthandler.o \
 	  vmm.o \
-	  allocator.o \
 	  scheduler.o scheduler/task.o
 CXX_OBJ := $(addprefix $(OBJ_DIR)/, $(CXX_OBJ))
 CXX_DEP = $(CXX_OBJ:%.o=%.d)
-- 
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