From 327fbc70c66400c18382dd3c188383e1eacfe338 Mon Sep 17 00:00:00 2001
From: ngiddings <nathang567@gmail.com>
Date: Sat, 10 Apr 2021 19:16:31 -0500
Subject: [PATCH] Implemented page allocator in C; removed C++.

---
 src/pageallocator.c        | 30 ++++++++++++++++++++++
 src/pageallocator.hpp      | 43 -------------------------------
 src/pageallocatorstack.cpp | 52 --------------------------------------
 src/pageallocatorstack.hpp | 34 -------------------------
 4 files changed, 30 insertions(+), 129 deletions(-)
 create mode 100644 src/pageallocator.c
 delete mode 100755 src/pageallocator.hpp
 delete mode 100644 src/pageallocatorstack.cpp
 delete mode 100644 src/pageallocatorstack.hpp

diff --git a/src/pageallocator.c b/src/pageallocator.c
new file mode 100644
index 0000000..631e578
--- /dev/null
+++ b/src/pageallocator.c
@@ -0,0 +1,30 @@
+#include "pageallocator.h"
+#include "types/status.h"
+
+physaddr_t reserve_page(struct page_stack_t *stack)
+{
+    if(stack->stack_pointer < stack->base_pointer)
+    {
+        physaddr_t frame = *stack->stack_pointer;
+        *stack->stack_pointer = (physaddr_t) 0;
+        stack->stack_pointer++;
+        return frame;
+    }
+    return S_OUT_OF_MEMORY;
+}
+
+int free_page(struct page_stack_t *stack, physaddr_t location)
+{
+    if(stack->stack_pointer > stack->limit_pointer)
+    {
+        stack->stack_pointer--;
+        *stack->stack_pointer = location;
+        return S_OK;
+    }
+    return S_OUT_OF_MEMORY;
+}
+
+size_t free_page_count(struct page_stack_t *stack)
+{
+    return stack->base_pointer - stack->stack_pointer;
+}
\ No newline at end of file
diff --git a/src/pageallocator.hpp b/src/pageallocator.hpp
deleted file mode 100755
index 2e600a7..0000000
--- a/src/pageallocator.hpp
+++ /dev/null
@@ -1,43 +0,0 @@
-#ifndef __MEMORYALLOCATOR_H_
-#define __MEMORYALLOCATOR_H_
-
-#include <stddef.h>
-#include "systypes.hpp"
-
-namespace kernelns
-{
-
-/**
- * Interface for a physical memory allocator.
- */
-class PageAllocator
-{
-public:
-
-	/**
-	 * Allocate a single page, returning its physical address. Upon failure,
-	 * returns an error code such that the least signifigant byte is nonzero.
-	 */
-	virtual physaddr_t next() = 0;
-
-	/**
-	 * Frees a single page that has previously been allocated.
-	 */
-	virtual void free(physaddr_t location) = 0;
-
-	/**
-	 * @returns the total number of free blocks of memory.
-	 */
-	virtual size_t freeBlocks() const = 0;
-
-	/**
-	 * @returns the total number of blocks managed by this memory 
-	 * allocator.
-	 */
-	virtual size_t getMemorySize() const = 0;
-	
-};
-	
-}
-
-#endif
diff --git a/src/pageallocatorstack.cpp b/src/pageallocatorstack.cpp
deleted file mode 100644
index 8425dcd..0000000
--- a/src/pageallocatorstack.cpp
+++ /dev/null
@@ -1,52 +0,0 @@
-#include "pageallocatorstack.hpp"
-#include "memorytype.hpp"
-
-using namespace kernelns;
-
-PageAllocatorStack::PageAllocatorStack(physaddr_t *stackBase, physaddr_t *stackTop, size_t frameSize, const MemoryMap& memoryMap)
-{
-    m_base = stackBase;
-    m_top = stackTop;
-    m_stack = m_base;
-    for(int i = 0; i < memoryMap.size(); i++)
-    {
-        if((MemoryType) memoryMap[i].getType() == MemoryType::Available)
-        {
-            for(int j = 0; j < memoryMap[i].getSize() / frameSize; j++)
-            {
-                free(memoryMap[i].getLocation() + j * frameSize);
-            }
-        }
-    }
-}
-
-physaddr_t PageAllocatorStack::next()
-{
-    if(m_stack < m_base)
-    {
-        physaddr_t frame = *m_stack;
-        *m_stack = (physaddr_t) 0;
-        m_stack++;
-        return frame;
-    }
-    return (physaddr_t) -1;
-}
-
-void PageAllocatorStack::free(physaddr_t location)
-{
-    if(m_stack > m_top)
-    {
-        m_stack--;
-        *m_stack = location;
-    }
-}
-
-size_t PageAllocatorStack::freeBlocks() const
-{
-    return m_base - m_stack;
-}
-
-size_t PageAllocatorStack::getMemorySize() const
-{
-    return m_totalSize;
-}
\ No newline at end of file
diff --git a/src/pageallocatorstack.hpp b/src/pageallocatorstack.hpp
deleted file mode 100644
index f5710ed..0000000
--- a/src/pageallocatorstack.hpp
+++ /dev/null
@@ -1,34 +0,0 @@
-#ifndef PAGEALLOCATORSTACK_H
-#define PAGEALLOCATORSTACK_H
-
-#include "pageallocator.hpp"
-#include "memorymap.hpp"
-
-namespace kernelns
-{
-
-class PageAllocatorStack : public PageAllocator
-{
-public:
-
-    PageAllocatorStack(physaddr_t *stackBase, physaddr_t *stackTop, size_t frameSize, const MemoryMap& memoryMap);
-
-    virtual physaddr_t next();
-
-    virtual void free(physaddr_t location);
-
-    virtual size_t freeBlocks() const;
-
-    virtual size_t getMemorySize() const;
-
-private:
-
-    size_t m_totalSize;
-
-    physaddr_t *m_stack, *m_base, *m_top;
-
-};
-
-}
-
-#endif
\ No newline at end of file