Merge branch 'lru-sample' into 'master'

Lru sample

See merge request !1

LRU.c

@@ -6,6 +6,7 @@
 #include <unistd.h>
 #include <string.h> 
 #include <stdatomic.h> 
+#include <assert.h>
 #include "LRU.h"
 #define ATOMIC_TEST_AND_SET  __atomic_test_and_set
 #define CLEAR __atomic_clear
@@ -13,7 +14,7 @@
 
 
 struct KV *array[MAX_SIZE];
-struct queue *qu;
+struct queue *qu=NULL;
 struct queue *last;
 
 
@@ -22,15 +23,24 @@ struct queue *last;
 void remove_element_from_deque(char *key)
 {
     queue *present = qu , *previous=NULL;
+    if(present == NULL)
+        return;
+    
+    if(strcmp(present->key, key) == 0)
+    {
+        qu = qu->next;
+        if(last == present)
+            last = last->next;
+        free(present);
+        return;
+    }
+
     while(present->next != NULL)
     {
-        if(present->key == key)
+        if(strcmp(present->key, key) == 0)
         {
-            if(previous == NULL)
-                qu = qu->next;
             if(last == present)
                 last = previous;
-            if(previous)
             previous->next = present->next;
             free(present);
             return;
@@ -43,7 +53,7 @@ void remove_element_from_deque(char *key)
 void insert_into_queue(char *key)
 {
     queue *temp = (queue *)malloc(sizeof(queue));
-    temp->key = key;
+    memcpy(temp->key, key, KEY_SIZE);
     temp->next = NULL;
     if(qu == NULL)
     {
@@ -57,6 +67,23 @@ void insert_into_queue(char *key)
     }
 }
 
+int remove_front_element()
+{
+    queue *temp = qu;
+    qu = qu->next;
+    assert(temp != NULL);
+    assert(qu != NULL);
+    for(int i=0;i<MAX_SIZE;i++)
+    {
+        if(strcmp(array[i]->key , temp->key) == 0)
+        {
+            // check if it is modified to write to file
+            array[i]->valid = FALSE;
+            return i;
+        }
+    }
+}
+
 int find_empty_location()
 {
     for(int i=0;i<MAX_SIZE;i++)
@@ -64,6 +91,7 @@ int find_empty_location()
         if(array[i]->valid == FALSE)
             return i;
     }
+    return remove_front_element();
 }
 
 int cache_del(char *key)
@@ -93,6 +121,7 @@ void cache_put(char *key, char *value)
         if(array[i]->key!=NULL) {
             if(strcmp(array[i]->key , key) == 0)
             {
+                printf("ENTERING INTO QUEUE\n");
                 indx = i;
                 remove_element_from_deque(key);
                 break;
@@ -104,6 +133,7 @@ void cache_put(char *key, char *value)
     if(indx == -1)
     {
         indx = find_empty_location();
+        assert(indx>=0);
         // TODO should write to file if modified is true
         // replacment from cache
     }
@@ -115,7 +145,6 @@ void cache_put(char *key, char *value)
     array[indx]->modified = TRUE;
     insert_into_queue(key);
     CLEAR(&(array[indx]->lock),0);
-    printf("Cache after PUT: \n");
     print_cache();
 }
 

LRU.h

@@ -22,7 +22,7 @@ typedef struct KV KV;
 typedef struct queue queue;
 
 struct queue{
-    char *key;
+    char key[KEY_SIZE];
     struct queue *next;
 };
 
@@ -45,3 +45,5 @@ int cache_get(char *key, char *value);
 void init_cache();
 
 void print_cache();
+
+int remove_front_element();
\ No newline at end of file