Fixed 'possible null pointer dereference' warning messages

lib/checkmemoryleak.cpp

@@ -811,6 +811,8 @@ const char * CheckMemoryLeakInFunction::call_func(const Token *tok, std::list<co
                 // Check if the function deallocates the variable..
                 while (ftok && (ftok->str() != "{"))
                     ftok = ftok->next();
+                if (!ftok)
+                    return 0;
                 Token *func = getcode(ftok->tokAt(1), callstack, parameterVarid, alloctype, dealloctype, false, sz);
                 //simplifycode(func, all);
                 const Token *func_ = func;

lib/checkother.cpp

@@ -876,6 +876,8 @@ void CheckOther::invalidFunctionUsage()
         const Token *tok2 = tok->tokAt(3);
         while (tok2 && tok2->str() != ",")
             tok2 = tok2->next();
+        if (!tok2)
+            continue;
 
         // is any source buffer overlapping the target buffer?
         int parlevel = 0;

lib/checkstl.cpp

@@ -763,7 +763,8 @@ void CheckStl::if_find()
                 while (decl && !Token::Match(decl, "[;{}(,]"))
                     decl = decl->previous();
 
-                decl = decl->next();
+                if (decl)
+                    decl = decl->next();
 
                 // stl container
                 if (Token::Match(decl, "const| std :: %var% < %type% > &|*| %varid%", varid))
@@ -1137,8 +1138,10 @@ void CheckStl::checkAutoPointer()
                         {
                             tok3 = tok3->next();
                         }
+                        if (!tok3)
+                            continue;
                         tok3 = tok3->previous()->previous();
-                        if (Token::Match(tok3->previous(), "[ ] )"))
+                        if (Token::simpleMatch(tok3->previous(), "[ ] )"))
                         {
                             autoPointerArrayError(tok2->next());
                         }

lib/checkuninitvar.cpp

@@ -1088,7 +1088,7 @@ public:
                 }
 
                 // found simple function..
-                if (tok2->link() == tok->tokAt(2))
+                if (tok2 && tok2->link() == tok->tokAt(2))
                     func.insert(tok->next()->str());
             }
         }