Use more Effective C++ code style in Token class:

1)The non-const version of Token::tokAt and Token::linkAt now will use a combination of const_cast and static_cast to remove duplicate code.
2)The non-const versions of Token::find(simple)match are added, in order to avoid the usage of const_cast outside the Token code.
3)As a consequence of 2), an useless const_cast applied to a call of Token::findsimplematch in Tokenizer code is removed.

lib/token.cpp

@@ -279,20 +279,6 @@ const Token *Token::tokAt(int index) const
     return tok;
 }
 
-Token *Token::tokAt(int index)
-{
-    Token *tok = this;
-    int num = std::abs(index);
-    while (num > 0 && tok) {
-        if (index > 0)
-            tok = tok->next();
-        else
-            tok = tok->previous();
-        --num;
-    }
-    return tok;
-}
-
 const Token *Token::linkAt(int index) const
 {
     const Token *tok = this->tokAt(index);
@@ -302,15 +288,6 @@ const Token *Token::linkAt(int index) const
     return tok->link();
 }
 
-Token *Token::linkAt(int index)
-{
-    Token *tok = this->tokAt(index);
-    if (!tok) {
-        throw InternalError(this, "Internal error. Token::linkAt called with index outside the tokens range.");
-    }
-    return tok->link();
-}
-
 const std::string &Token::strAt(int index) const
 {
     static const std::string empty_str;

lib/token.h

@@ -84,14 +84,18 @@ public:
      * would return next from that one.
      */
     const Token *tokAt(int index) const;
-    Token *tokAt(int index);
+    Token *tokAt(int index) {
+        return const_cast<Token *>(static_cast<const Token *>(this)->tokAt(index));
+    }
 
     /**
      * Returns the link to the token in given index, related to this token.
      * For example index 1 would return the link to next token.
      */
     const Token *linkAt(int index) const;
-    Token *linkAt(int index);
+    Token *linkAt(int index) {
+        return const_cast<Token *>(static_cast<const Token *>(this)->linkAt(index));
+    }
 
     const std::string &strAt(int index) const;
 
@@ -255,6 +259,18 @@ public:
     static const Token *findsimplematch(const Token *tok, const char pattern[], const Token *end);
     static const Token *findmatch(const Token *tok, const char pattern[], unsigned int varId = 0);
     static const Token *findmatch(const Token *tok, const char pattern[], const Token *end, unsigned int varId = 0);
+    static Token *findsimplematch(Token *tok, const char pattern[]) {
+        return const_cast<Token *>(findsimplematch(static_cast<const Token *>(tok), pattern));
+    }
+    static Token *findsimplematch(Token *tok, const char pattern[], const Token *end) {
+        return const_cast<Token *>(findsimplematch(static_cast<const Token *>(tok), pattern, end));
+    }
+    static Token *findmatch(Token *tok, const char pattern[], unsigned int varId = 0) {
+        return const_cast<Token *>(findmatch(static_cast<const Token *>(tok), pattern, varId));
+    }
+    static Token *findmatch(Token *tok, const char pattern[], const Token *end, unsigned int varId = 0) {
+        return const_cast<Token *>(findmatch(static_cast<const Token *>(tok), pattern, end, varId));
+    }
 
     /**
      * Needle is build from multiple alternatives. If one of

lib/tokenize.cpp

@@ -8745,7 +8745,7 @@ void Tokenizer::simplifyNamespaceStd()
     };
     static const std::set<std::string> stdFunctions(stdFunctions_, stdFunctions_+sizeof(stdFunctions_)/sizeof(*stdFunctions_));
 
-    for (Token* tok = const_cast<Token*>(Token::findsimplematch(list.front(), "using namespace std ;")); tok; tok = tok->next()) {
+    for (Token* tok = Token::findsimplematch(list.front(), "using namespace std ;"); tok; tok = tok->next()) {
         bool insert = false;
         if (Token::Match(tok, "%var% (") && !Token::Match(tok->previous(), ".|::") && stdFunctions.find(tok->str()) != stdFunctions.end())
             insert = true;