//---------------------------------------------------------------------------

#include <vcl.h>
#pragma hdrstop

#include "DPartition.h"
#include "malloc.h"

//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TMainFrm *MainFrm;
//--------------------------------------------------------------------------- 
__fastcall TMainFrm::TMainFrm(TComponent* Owner)
	: TForm(Owner)
{
}
//---------------------------------------------------------------------------
typedef struct LNode
{
	struct LNode *prior;//前趨結(jié)點(diǎn)  
    int size;	//內(nèi)存空間大小
    int address;	//首地址
    struct LNode *next;//后繼結(jié)點(diǎn)
    String fileName;	//分配給的文件名
}LNode,*FreeList;

FreeList head,cur;

int maxSize = 640,minSize = 10;
//---------------------------------------------------------------------------
void Display()
{
    MainFrm->Memo1->Lines->Add("當(dāng)前空閑分區(qū)鏈信息如下：");
    MainFrm->Memo1->Lines->Add("分區(qū)大小(KB)\t分區(qū)始址\t狀態(tài)\t作業(yè)名");
    cur = head->next;
    while(cur != NULL)
    {
    	if(cur->fileName == "")
    		MainFrm->Memo1->Lines->Add(IntToStr(cur->size)+"\t\t0x"+IntToHex(cur->address * 1024,8)+"\t空閑\t"+cur->fileName);
        else
        	MainFrm->Memo1->Lines->Add(IntToStr(cur->size)+"\t\t0x"+IntToHex(cur->address * 1024,8)+"\t已用\t"+cur->fileName);
        cur = cur->next;
    }
}
//--------------------------------------------------------------------------- 
void __fastcall TMainFrm::FormCreate(TObject *Sender)
{
	head = (FreeList) malloc (sizeof(LNode));
    head->next = head->prior = NULL;	//建立一個(gè)帶頭結(jié)點(diǎn)的雙向鏈表
    FreeList temp = (FreeList) malloc (sizeof(LNode));	//生成一個(gè)新結(jié)點(diǎn)
    temp->size = maxSize;
    temp->address = 0;
    temp->fileName = "";
    temp->next = head->next;
    temp->prior = head;
    head->next = temp;
}
//---------------------------------------------------------------------------
//空閑分區(qū)的分配算法
bool __fastcall TMainFrm::Apply(String fileName,int size)
{        
	FreeList temp = (FreeList) malloc (sizeof(LNode));
    FreeList min = (FreeList) malloc (sizeof(LNode));
    //查找第一個(gè)符合要求的結(jié)點(diǎn)
    for(cur = head->next;cur && cur->fileName != "" || cur->size < size;cur = cur->next);
    min = cur;
    if(BF->Checked)//如果選擇的是最佳適應(yīng)算法則要查找出所有符合要求結(jié)點(diǎn)中最小的一個(gè)
    {
    	for(cur;cur;cur = cur->next)
        	if(cur->size < min->size && cur->fileName == "") min = cur;
    }
    if(min)
    {
    	if(min->size - size <= minSize) temp = min;//不可再分則直接分配給作業(yè)
        else
        {//從可用分區(qū)中劃出size大小的內(nèi)存空間                           
        	temp->size =size;
            temp->address = min->address;
            min->size -= size;
            min->address += size;           
        	temp->prior = min->prior;
            min->prior->next = temp; 
        	min->prior = temp;
        	temp->next = min;  
        }
        temp->fileName = fileName;
        return true;
    }
    else return false;
}
//---------------------------------------------------------------------------
//空間釋放算法
void __fastcall TMainFrm::SetFree(String fileName)
{
    for(cur = head->next;cur && cur->fileName != fileName;cur = cur->next);//找到結(jié)點(diǎn)
    if(cur)
    {
    	if(cur->prior != head && cur->prior->fileName == "")
    	{//不為第一結(jié)點(diǎn)且與前一可用區(qū)相鄰          
            if(cur->next != NULL && cur->next->fileName == "")
            {//與后一可用分區(qū)相鄰
            	cur->size += cur->next->size;
                cur->next = cur->next->next;
                if(cur->next->next != NULL) cur->next->next->prior = cur;
            }         
        	cur->prior->size += cur->size;
            cur->prior->next = cur->next;
            if(cur->next != NULL) cur->next->prior = cur->prior;
    	}
        else if(cur->next != NULL && cur->next->fileName == "")
        {//與后一可用分區(qū)相鄰且不為空表目
        	cur->fileName = "";
        	cur->size += cur->next->size;
            cur->next = cur->next->next;
            if(cur->next->next != NULL) cur->next->next->prior = cur;
        }
    	else
    	{
    		cur->fileName = "";
    	}
    }
    else MessageBox(NULL,"釋放空間失敗！","警告",false);
}
//---------------------------------------------------------------------------
void __fastcall TMainFrm::Btn_CreateClick(TObject *Sender)
{
	String fileName;
    int size;
    if(Edit_CName->Text == "")
    {
    	MessageBox(NULL,"請(qǐng)輸入作業(yè)名！","錯(cuò)誤",false);
        return;
    }
    else if(Edit_Size->Text == "")
    {
		MessageBox(NULL,"請(qǐng)輸入作業(yè)的大小！","錯(cuò)誤",false);
        return;
    }
    fileName = Edit_CName->Text;
    size = StrToInt(Edit_Size->Text);
    if(Apply(fileName,size)) Display();
    else MessageBox(NULL,"沒有足夠的可用空間！","提示",false);
}
//---------------------------------------------------------------------------
void __fastcall TMainFrm::Btn_FreeClick(TObject *Sender)
{
	String fileName;
    fileName = Edit_FName->Text;
    SetFree(fileName);
    Display();
}
//---------------------------------------------------------------------------
void __fastcall TMainFrm::FormClose(TObject *Sender, TCloseAction &Action)
{
	for(cur = head;cur;cur = cur->next) free(cur);	
}
//---------------------------------------------------------------------------