天津理工大学_操作系统_存储器的分配与回收算法实现_实验报告
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实验报告学院（系）名称：计算机与通信工程学院
【实验过程记录（源程序、测试用例、测试结果及心得体会等）】源程序:
MemoryBlock.java:
//内存块类，包含各种操作
public class MemoryBlock {
static final int BLOCK_SIZE = 4096;
private int baseBlock; //内存块基地址
private int blockNum; //大小
private boolean inUse; //是否已分配
private MemoryBlock prev, next;
public MemoryBlock(int blockNum) {
this.baseBlock = 0;
this.blockNum = blockNum;
inUse = false;
prev = null;
next = null;
}
public MemoryBlock(int base, int blockNum) {
this.baseBlock = base;
this.blockNum = blockNum;
inUse = false;
prev = null;
next = null;
}
public int getBlockNum() {
return blockNum;
}
public void setBlockNum(int blockNum) {
this.blockNum = blockNum;
}
public MemoryBlock getPrev() {
return prev;
}
public void setPrev(MemoryBlock prev) {
this.prev = prev;
public MemoryBlock getNext() {
return next;
}
public void setNext(MemoryBlock next) {
this.next = next;
}
public boolean inUse() {
return inUse;
}
public void setUse() {
inUse = true;
}
public void free() {
inUse = false;
}
public int getBaseBlock() {
return baseBlock;
}
public void setBaseBlock(int baseBlock) { this.baseBlock = baseBlock;
}
//分配内存块，如果可分配，则返回剩余内存块
public MemoryBlock allocate(int blockNum) { if(this.blockNum - blockNum>0) {
int newBase = baseBlock + blockNum;
int newBlock = this.blockNum-blockNum;
this.blockNum = blockNum;
setUse();
return new MemoryBlock(newBase, newBlock);
}
else if(this.blockNum - blockNum ==0) {
this.blockNum = 0;
}
return null;
}
//判断内存块是否能合并
public boolean merge(MemoryBlock memBlock) {
if(baseBlock+blockNum==memBlock.getBaseBlock()) {
setBlockNum(blockNum+memBlock.blockNum);
memBlock.setBaseBlock(0);
memBlock.setBlockNum(0);
return true;
}
else
return false;
}
@Override
public String toString() {
String inUse = null;
if(inUse())inUse = "已分配";
else inUse = "未分配";
return"内存块 [基地址=" + baseBlock + ", 大小=" + blockNum +
", " + inUse + "]";
}
}
MemoryTable.java:
//虚类MemTable，提供内存链表的各种基本方法
public abstract class MemoryTable {
//MemoryBlock链表表头
protected MemoryBlock memList;
public MemoryTable(int blockNum) {
memList = new MemoryBlock(0, blockNum);
}
//把newBlock插入到memBlock前面
public void insertBefore(MemoryBlock memBlock, MemoryBlock newBlock){
if(memBlock.getPrev() != null)
memBlock.getPrev().setNext(newBlock);
if(memList == memBlock)
memList = newBlock;
newBlock.setPrev(memBlock.getPrev());
newBlock.setNext(memBlock);
memBlock.setPrev(newBlock);
}