修正堆释放后Used计算错误，不能用下一块指针减去当前指针，因为最后一块可能没有用完

Kernel/Heap.cpp

@@ -5,6 +5,9 @@
 
 #define MEMORY_ALIGN	4
 
+// 当前堆
+Heap* Heap::Current	= nullptr;
+
 /*
 堆分配原理：
 1，使用内存块，记录当前块已使用大小以及下一块地址，形成内存块链表
@@ -25,6 +28,8 @@ typedef struct MemoryBlock_
 /******************************** Heap ********************************/
 Heap::Heap(uint addr, uint size)
 {
+	Current	= this;
+
 	// 地址对齐
 	uint end	= addr + size;
 	addr	= (addr + MEMORY_ALIGN - 1) & (~(MEMORY_ALIGN - 1));
@@ -42,10 +47,13 @@ Heap::Heap(uint addr, uint size)
 
 	_Used	= sizeof(MemoryBlock) << 1;
 	_Count	= 0;
+
+	debug_printf("Heap::Init(%p, %d) Free=%d \r\n", Address, Size, FreeSize());
 }
 
 uint Heap::Used()	const { return _Used; }
 uint Heap::Count()	const { return _Count; }
+uint Heap::FreeSize()	const { return Size - _Used; }
 
 void* Heap::Alloc(uint size)
 {
@@ -58,14 +66,19 @@ void* Heap::Alloc(uint size)
 		return nullptr;
 	}
 
+	// 检查头部完整性
+	auto head	= (MemoryBlock*)Address;
+	assert(head->Used <= Size && (uint)head + head->Used <= (uint)head->Next, "堆头被破坏！");
+	assert(_Used <= Size, "Heap::Used异常！");
+
 	void* ret	= nullptr;
 	int need	= size + sizeof(MemoryBlock);
 
 	SmartIRQ irq;
 	for(auto mcb=(MemoryBlock*)Address; mcb->Next!=nullptr; mcb=mcb->Next)
 	{
-		// 找到一块满足大小的内存块
-		int free	= (uint)mcb->Next - (uint)mcb - mcb->Used;
+		// 找到一块满足大小的内存块。计算当前块剩余长度
+		int free	= (int)mcb->Next - (int)mcb - mcb->Used;
 		if(free >= need)
 		{
 			// 割一块出来
@@ -79,6 +92,8 @@ void* Heap::Alloc(uint size)
 			_Used	+= need;
 			_Count++;
 
+			debug_printf("Heap::Alloc (%p, %d) Used=%d Count=%d \r\n", ret, need, _Used, _Count);
+
 			break;
 		}
 	}
@@ -96,11 +111,14 @@ void Heap::Free(void* ptr)
 	SmartIRQ irq;
 	for(auto find=prev->Next; find->Next!=nullptr; find=find->Next)
 	{
+		// 找到内存块
 		if(find == mcb)
 		{
-			_Used	-= (uint)find->Next - (uint)prev->Next;
+			_Used	-= find->Used;
 			_Count--;
 
+			debug_printf("Heap::Free  (%p, %d) Used=%d Count=%d \r\n", ptr, find->Used, _Used, _Count);
+
 			prev->Next = find->Next;
 
 			break;

Kernel/Heap.h

@@ -9,13 +9,17 @@ public:
 	uint	Size;	// 大小
 
 	Heap(uint addr, uint size);
-	
+
 	uint Used() const;	// 已使用内存数
 	uint Count() const;	// 已使用内存块数
-	
+	uint FreeSize() const;	// 可用内存数
+
 	void* Alloc(uint size);
 	void Free(void* ptr);
-	
+
+	// 当前堆
+	static Heap* Current;
+
 private:
 	uint	_Used;
 	uint	_Count;