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#!/usr/bin/env python3
# UPEM / System programming / Project: Memory paging simulator
# Pacien TRAN-GIRARD, Adam NAILI
from mem import Memory
from pageexception import *
class LruPaginator:
def __init__(self, mem):
self.mem = mem
self._global_counter = 1
self._check_table = [0 for _ in range(len(mem.main) + len(mem.virt))]
self._main_cursor = 0
def _update_check_table(self, page):
"""
>>> lru = LruPaginator(Memory(3,5))
>>> page = 3
>>> lru._update_check_table(page)
>>> print(lru._check_table[page])
1
>>> print(lru._global_counter)
2
"""
self._check_table[page] = self._global_counter
self._global_counter += 1
def _check_where_to_replace(self):
"""
>>> lru = LruPaginator(Memory(3, 5))
>>> lru._check_where_to_replace()
>>> print(lru._main_cursor)
0
>>> lru.mem.main = [3, 4, 2]
>>> lru._check_table = [1, 3, 6, 4, 5, 0, 0, 0]
>>> lru._check_where_to_replace()
>>> print(lru._main_cursor)
0
"""
for page in self.mem.main:
if page is None:
self._main_cursor = self.mem.main.index(page)
return
min = self._check_table[self.mem.main[0]]
self._main_cursor = 0
for page in self.mem.main:
if min > self._check_table[page]:
min = self._check_table[page]
self._main_cursor = self.mem.main.index(page)
def _put_main(self, page):
self._check_where_to_replace()
print("Cursor:")
print(self._main_cursor)
print("")
overwritten = self.mem.main[self._main_cursor]
self.mem.main[self._main_cursor] = page
self._update_check_table(page)
return overwritten
def load(self, page):
if not self.mem.page_in_range(page): raise PageException
if page in self.mem.main:
self._update_check_table(page)
return
if page in self.mem.virt: self.mem.remove_virt(page)
overwritten = self._put_main(page)
if overwritten is not None: self.mem.put_virt(overwritten)
if __name__ == "__main__":
import doctest
doctest.testmod()
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