From 3dc844c1dfea604bc43890794a5cbc4c5fdef89d Mon Sep 17 00:00:00 2001
From: Adam NAILI
Date: Mon, 2 Apr 2018 16:14:45 +0200
Subject: PageException created and LRU,Second Chance Handling

---
 fifo.py          |  3 ++-
 lru.py           | 71 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 myMemory.py      | 10 +++++---
 pageexception.py |  3 +++
 secondchance.py  | 34 +++++++++++++++++++++++++++
 5 files changed, 117 insertions(+), 4 deletions(-)
 create mode 100644 lru.py
 create mode 100644 pageexception.py
 create mode 100644 secondchance.py

diff --git a/fifo.py b/fifo.py
index 61e70f5..c48629f 100644
--- a/fifo.py
+++ b/fifo.py
@@ -4,6 +4,7 @@
 # Pacien TRAN-GIRARD et Adam NAILI
 
 from mem import Memory
+from pageexception import *
 
 
 class FifoPaginator:
@@ -18,7 +19,7 @@ class FifoPaginator:
     return overwritten
 
   def load(self, page):
-    if not self.mem.page_in_range(page): raise IndexError
+    if not self.mem.page_in_range(page): raise PageException
     if page in self.mem.main: return
     if page in self.mem.virt: self.mem.remove_virt(page)
     overwritten = self._put_main(page)
diff --git a/lru.py b/lru.py
new file mode 100644
index 0000000..3042bba
--- /dev/null
+++ b/lru.py
@@ -0,0 +1,71 @@
+#!/usr/bin/env python3
+
+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()
diff --git a/myMemory.py b/myMemory.py
index 2439aae..6e1014a 100755
--- a/myMemory.py
+++ b/myMemory.py
@@ -4,10 +4,14 @@
 # Pacien TRAN-GIRARD et Adam NAILI
 
 from mem import Memory
+from pageexception import *
 from fifo import FifoPaginator
-
+from lru import LruPaginator
+from secondchance import SecondChancePaginator
 paginators = {
-  'fifo': FifoPaginator
+  'fifo': FifoPaginator,
+  'lru': LruPaginator,
+  'secondchance': SecondChancePaginator
 }
 
 
@@ -25,7 +29,7 @@ def main(main_size, virt_size, paginator):
       try:
         pag.load(int(cmd))
         output(cmd, mem.dump_main())
-      except IndexError:
+      except PageException:
         output(cmd, "Error: invalid page.")
     elif cmd == 'p':
       output(cmd, mem.dump_main() + '\t' + mem.dump_virt())
diff --git a/pageexception.py b/pageexception.py
new file mode 100644
index 0000000..9a1519d
--- /dev/null
+++ b/pageexception.py
@@ -0,0 +1,3 @@
+class PageException(Exception):
+    def __init__(self):
+      super().__init__()
diff --git a/secondchance.py b/secondchance.py
new file mode 100644
index 0000000..b0fb1f9
--- /dev/null
+++ b/secondchance.py
@@ -0,0 +1,34 @@
+#!/usr/bin/env python3
+
+# UPEM / Programmation système / Projet : Simulation de gestion de mémoire virtuelle
+# Pacien TRAN-GIRARD et Adam NAILI
+
+from mem import Memory
+from pageexception import *
+
+
+class SecondChancePaginator:
+  def __init__(self, mem):
+    self.mem = mem
+    self._check_table = [0 for _ in range(len(mem.main)+len(mem.virt))]
+    self._main_cursor = 0
+
+  def _put_main(self, page):
+    overwritten = self.mem.main[self._main_cursor]
+    while(overwritten is not None and self._check_table[overwritten] == 1):
+      self._main_cursor=(self._main_cursor + 1) % len(self.mem.main)
+      self._check_table[overwritten] = 0
+      overwritten = self.mem.main[self._main_cursor]
+    self.mem.main[self._main_cursor] = page
+    self._main_cursor = (self._main_cursor + 1) % len(self.mem.main)
+    return overwritten
+
+  def load(self, page):
+    if not self.mem.page_in_range(page): raise PageException
+    if page in self.mem.main: 
+      self._check_table[page] = 1
+      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)
+
-- 
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