最近做实验，要求用文件存取数据，上网搜，主要都是C语言或者Java写的，Python的粗略看是没搜到。
所以想到用Python来写， *** 作文件更方便一些。
废话不多说，直接上代码
class load_from_file:
file_name = None #文件名
file = None #文件对象
is_pre = None #是否有预先页
block = None #物理块数量
pre_list = None #预先页内容
visit_list = None #访问列表
def __init__(self) -> None:
self.load("page_src.txt")
def load(self,name):
self.file_name = name
self.file = open(self.file_name,"r+")
fr = self.file.read()
str1 = fr.split("n")
list1 = str1[0].split(" ")#文件中保存两行数据
list2 = str1[1].split(" ")
for i in range(len(list1)):
list1[i] = eval(list1[i])
for i in range(len(list2)):
list2[i] = eval(list2[i])
self.block = list1[0]#第一行第一个数字表示有几个物理块
if list1[1] != 0:#第一行第二个数据表示是否有预先页，后面的数据则是预先页中的内容，后面的数据项长度应该小于第一个数字
self.is_pre = True
self.pre_list = list1[2:]
if len(self.pre_list) > self.block:
print("错误，请检查传入文件内容是否正确")
return
self.visit_list = list2#第二行表示访问页的列表
self.file.close()
class dispatch:
is_pre = None
block = None
pre_list = None
now_list = None #当前访问页列表
visit_list = None
is_lack = None #是否缺页
res_list = None #保存结果便于写入文件
def __init__(self) -> None:#初始化数据
self.block = load_from_file().block
self.is_pre = load_from_file().is_pre
self.pre_list = load_from_file().pre_list
self.visit_list = load_from_file().visit_list
self.now_list = [0]*self.block
self.is_lack = [True]*len(self.visit_list)
self.res_list = []
def OPT(self) -> list:
if self.is_pre:
for i in range(len(self.pre_list)):
self.now_list[i] = self.pre_list[i]
future_count = [-1]*self.block
for i in range(len(self.visit_list)):
if self.visit_list[i] in self.now_list:#如果访问的页在当前表中，则不缺页
self.is_lack[i] = False
#print(self.now_list)
res_temp = [x for x in self.now_list]
res_temp.append(self.is_lack[i])
self.res_list.append(res_temp)
continue
if 0 in self.now_list:
self.now_list[self.now_list.index(0)] = self.visit_list[i]
res_temp = [x for x in self.now_list]
res_temp.append(self.is_lack[i])
self.res_list.append(res_temp)
continue
for j in range(self.block):#缺页，计算最久访问页
if self.now_list[j] in self.visit_list[i:]:
future_count[j] = self.visit_list[i:].index(self.now_list[j])
else:
future_count[j] = len(self.visit_list)
self.now_list[future_count.index(max(future_count))] = self.visit_list[i]#替换
#print(self.now_list)
res_temp = [x for x in self.now_list]
res_temp.append(self.is_lack[i])
self.res_list.append(res_temp)
return self.res_list
def FIFO(self):
if self.is_pre:
for i in range(len(self.pre_list)):
self.now_list[i] = self.pre_list[i]
exist_count = [0]*self.block
self.pre_list = [x for x in self.now_list]
for i in range(len(self.visit_list)):
for j in range(self.block):
if self.now_list[j] == self.pre_list[j]:
exist_count[j] += 1
else:
exist_count[j] = 0
if self.visit_list[i] in self.now_list:#如果访问的页在当前表中，则不缺页
self.is_lack[i] = False
res_temp = [x for x in self.now_list]
res_temp.append(self.is_lack[i])
self.res_list.append(res_temp)
#print(self.now_list)
continue
if 0 in self.now_list:
self.now_list[self.now_list.index(0)] = self.visit_list[i]
res_temp = [x for x in self.now_list]
res_temp.append(self.is_lack[i])
self.res_list.append(res_temp)
continue
self.pre_list = [i for i in self.now_list]#储存未置换前的页
self.now_list[exist_count.index(max(exist_count))] = self.visit_list[i]
#print(self.now_list)
res_temp = [x for x in self.now_list]
res_temp.append(self.is_lack[i])
self.res_list.append(res_temp)
return self.res_list
def LRU(self):
if self.is_pre:
for i in range(len(self.pre_list)):
self.now_list[i] = self.pre_list[i]
unused_time = [0]*self.block
for i in range(len(self.visit_list)):
if self.visit_list[i] in self.now_list:#如果访问的页在当前表中，则不缺页
self.is_lack[i] = False
res_temp = [x for x in self.now_list]
res_temp.append(self.is_lack[i])
self.res_list.append(res_temp)
#print(self.now_list)
continue
if 0 in self.now_list:
self.now_list[self.now_list.index(0)] = self.visit_list[i]
res_temp = [x for x in self.now_list]
res_temp.append(self.is_lack[i])
self.res_list.append(res_temp)
continue
for j in range(self.block):
if self.now_list[j] not in self.visit_list[:i]:
unused_time[j] = len(self.visit_list)
else:
temp_list = [x for x in self.visit_list[:i]]
temp_list.reverse()
unused_time[j] = temp_list.index(self.now_list[j])
self.now_list[unused_time.index(max(unused_time))] = self.visit_list[i]
#print(self.now_list)
res_temp = [x for x in self.now_list]
res_temp.append(self.is_lack[i])
self.res_list.append(res_temp)
return self.res_list
def main(self):
while True:
print("1-OPTt2-FIFOt3-LRU")
choose = input("请选择调度方式：")
res = []
method = ""
if choose == "1":
res = dispatch().OPT()
method = "OPT"
elif choose == "2":
res = dispatch().FIFO()
method = "FIFO"
elif choose == "3":
res = dispatch().LRU()
method = "LRU"
else:
print("程序退出")
return
print(method,end="")
for i in self.visit_list:
print("t"+str(i),end="")
print()
count_lack = 0
for i in range(len(res[0])):
if i == len(res[0]) - 1:
print("缺页",end="")
for j in range(len(self.visit_list)):
if res[j][i] == True:
count_lack += 1
else:
print("块"+str(i),end="")
for j in range(len(self.visit_list)):
print("t"+str(res[j][i]),end="")
print()
print("缺页率",str(count_lack/len(self.is_lack)*100)+"%")
with open("page_res.txt","w",encoding="utf-8") as ff:
ff.write(method+" ")
for i in self.visit_list:
ff.write("t"+str(i))
ff.write("n")
for i in range(len(res[0])):
if i == len(res[0]) - 1:
ff.write("缺页")
else:
ff.write("块"+str(i)+" ")
for j in range(len(self.visit_list)):
if i == len(res[0]) - 1:
if res[j][i] == True:
ff.write("t1")
else:
ff.write("t0")
else:
ff.write("t"+str(res[j][i]))
ff.write("n")
ff.write("1代表缺页，0代表不缺页n缺页率 "+str(count_lack/len(self.is_lack)*100)+"%")
ff.close()
if __name__ == "__main__":
dispatch().main()
实验要求实现OPT、FIFO和LRU算法，非常简单
下面是测试用的源文件page_src.txt的内容
3 1 1 2 3 1 2 4 2 6 2 1 5 6 1
测试结果
OPT
OPT 1 2 4 2 6 2 1 5 6 1 块0 1 1 1 1 1 1 1 1 1 1 块1 2 2 2 2 2 2 2 5 5 5 块2 3 3 4 4 6 6 6 6 6 6 缺页 0 0 1 0 1 0 0 1 0 0 1代表缺页，0代表不缺页 缺页率 30.0%
FIFO
FIFO 1 2 4 2 6 2 1 5 6 1 块0 1 1 4 4 4 4 1 1 1 1 块1 2 2 2 2 6 6 6 5 5 5 块2 3 3 3 3 3 2 2 2 6 6 缺页 0 0 1 0 1 1 1 1 1 0 1代表缺页，0代表不缺页 缺页率 60.0%
LRU
LRU 1 2 4 2 6 2 1 5 6 1 块0 1 1 1 1 6 6 6 5 5 5 块1 2 2 2 2 2 2 2 2 6 6 块2 3 3 4 4 4 4 1 1 1 1 缺页 0 0 1 0 1 0 1 1 1 0 1代表缺页，0代表不缺页 缺页率 50.0%
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