Made changes to cache

cache.cpp

@@ -3,6 +3,7 @@
 #include <iterator> 
 #include <unordered_map>
 #include <string>
+#include "cs_thread.h"
 #include "cache.h"
 using namespace std;
 /* 
@@ -37,17 +38,19 @@ unordered_map<string, list <cacheNode> :: iterator> hashTable;
  * Returns 1 if key-value pair is present in cache and 0 otherwise
  * If key is present, brings correspoding node to front of the cache(To identify recently used element)
  */
-int search(string key) {
+string search(string key) {
     unordered_map<string, list <cacheNode> :: iterator> :: iterator it = hashTable.find(key);
     if(it == hashTable.end()) {
-        return 0;
+        string ans = "";
+        return ans;
     }
     else {
         list <cacheNode> :: iterator cnode_it = it->second;
         cache.push_front(*cnode_it);
         cache.erase(cnode_it);
         hashTable[key] = cache.begin();
-        return 1;
+        string ans = cnode_it->value;
+        return ans;
     }
 }
 
@@ -89,13 +92,29 @@ void insert(string key, string value) {
 /*
  * Delete from cache
  */ 
-void del(string key) {
+void DEL(string key) {
     unordered_map<string, list <cacheNode> :: iterator> :: iterator it = hashTable.find(key);
-    list <cacheNode> :: iterator cnode_it = it->second;
+    list<cacheNode> :: iterator cnode_it = it->second;
     cache.erase(cnode_it);
     hashTable.erase(key);
 }
 
+string GET(string key) {
+    string ans = search(key);
+    return ans;
+}
+
+string PUT(string key, string value) {
+    string ans = search(key);
+    if(ans == "") {
+        insert(key, value);
+    }
+    else {
+        unordered_map<string, list <cacheNode> :: iterator> :: iterator it = hashTable.find(key);
+        it->second->value = value;
+    }
+}
+
 /* 
  * Testing code
  */
@@ -141,7 +160,7 @@ int main() {
         cout << p.second->key << " " << p.second->value << " " << p.second->dirtyBit << endl;
     }
     printf("-----------------------------\n");
-    del(key5);
+    DEL(key5);
     for (auto p : hashTable) {
         cout << p.first << " : ";
         cout << p.second->key << " " << p.second->value << " " << p.second->dirtyBit << endl;