编写程序模拟完成动态分区存储管理方式的内存分配和回收。

#!/usr/bin/python
#-*- coding: utf-8 -*-

class Table(object):
#空闲分区表
#0:开始地址 1:长度
freeTable = []

#占用分区表
#0:程序名 1:开始地址 2:长度
useTable = []

def __init__(self):
print '初始化内存使用情况'
self.useTable.append(['os',0,10])
self.freeTable.append([10,100])

def WorkAdd(self):
memoryName = raw_input('请输入进程名:')
memoryName = memoryName.strip()
memorySize = int(raw_input('请输入进程大小:'))
if (memoryName != '' and memorySize > 0):
self._WorkAdd(memoryName, memorySize)
else:
print '输入有问题'

def _WorkAdd(self, memoryName, memorySize):
minIndex = -1
minMemory = 0
for i in xrange(len(self.freeTable)):
if (self.freeTable[i][1] > memorySize):
if (minIndex == -1):
minMemory = self.freeTable[i][1]
minIndex = i
else:
if (self.freeTable[i][1] < minMemory):
minMemory = self.freeTable[i][1]
minIndex = i
if (minIndex == -1):
self.outOfMemory()
else:
start = self.freeTable[minIndex][0]
length = self.freeTable[minIndex][1]
self.freeTable.remove(self.freeTable[minIndex])
self.useTable.append([memoryName,start,memorySize])
self.freeTable.append([start + memorySize,length - memorySize])
self.display()

def display(self):
print '已用分区表\n程序进程名\t开始地址\t长度'
for i in xrange(len(self.useTable)):
print self.useTable[i][0], '\t\t', self.useTable[i][1], '\t', self.useTable[i][2]
print '空闲分区表\n开始地址\t长度'
for i in xrange(len(self.freeTable)):
print self.freeTable[i][0], '\t\t', self.freeTable[i][1]

def outOfMemory(self):
print '亲，内存不够了'
self.display()

def WorkDel(self):
memoryName = raw_input('请输入进程名:')
memoryName = memoryName.strip()
if (memoryName == ''):
print '没有输入'
else:
self._WorkDel(memoryName)

def _WorkDel(self,memoryName):
index = -1;
for i in xrange(len(self.useTable)):
if (self.useTable[i][0] == memoryName):
index = i
break
if (index == -1):
print '不存在此进程'
else:
start = self.useTable[index][1]
length = self.useTable[index][2]
end = start + length
freeIndex1 = -1
freeIndex2 = -1
for i in xrange(len(self.freeTable)):
iStart = self.freeTable[i][0]
iLength = self.freeTable[i][1]
if (start == iStart + iLength):
freeIndex1 = i
break
for i in xrange(len(self.freeTable)):
if (self.freeTable[i][0] == end):
freeIndex2 = i
break
if (freeIndex1 != -1 and freeIndex2 != -1):
iStart = self.freeTable[freeIndex1][0]
iLength = self.freeTable[freeIndex1][1] + self.freeTable[freeIndex2][1] + length
self.freeTable.append([iStart,iLength])
self.freeTable.remove(self.freeTable[freeIndex1])
self.freeTable.remove(self.freeTable[freeIndex2])
elif (freeIndex1 != -1 and freeIndex2 == -1):
iStart = self.freeTable[freeIndex1][0]
iLength = self.freeTable[freeIndex1][1] + length
self.freeTable.append([iStart,iLength])
self.freeTable.remove(self.freeTable[freeIndex1])
elif (freeIndex1 == -1 and freeIndex2 != -1):
iStart = start
iLength = self.freeTable[freeIndex2][1] + length
self.freeTable.append([iStart,iLength])
self.freeTable.remove(self.freeTable[freeIndex2])
elif (freeIndex1 == -1 and freeIndex2 == -1):
iStart = start
iLength = length
self.freeTable.append([iStart,iLength])
else:
print '系统崩溃'
self.display()

def run(self):
while(True):
print '动态分区存储管理'
print '1,增加程序'
print '2,结束程序'
print '3,退出'
print '请选择操作:(输入数字)'
chose = raw_input('请选择操作:')
chose = chose.strip()
if (chose == '1'):
self.WorkAdd()
elif(chose == '2'):
self.WorkDel()
elif (chose == '3'):
break
else:
print '输入有误'
print '\n'

if __name__ == '__main__':
table = Table()
table.run()