Fix #1018 (strcat(strcat()) causes assertion in Tokenizer::validate)

Test case provided by povaddict
http://sourceforge.net/apps/trac/cppcheck/ticket/1018

lib/token.cpp

@@ -535,6 +535,23 @@ bool Token::isStandardType() const
     return ret;
 }
 
+void Token::move(Token *srcStart, Token *srcEnd, Token *newLocation)
+{
+    /**[newLocation] -> b -> c -> [srcStart] -> [srcEnd] -> f */
+
+    // Fix the gap, which tokens to be moved will leave
+    srcStart->previous()->next(srcEnd->next());
+    srcEnd->next()->previous(srcStart->previous());
+
+    // Fix the tokens to be moved
+    srcEnd->next(newLocation->next());
+    srcStart->previous(newLocation);
+
+    // Fix the tokens at newLocation
+    newLocation->next()->previous(srcEnd);
+    newLocation->next(srcStart);
+}
+
 //---------------------------------------------------------------------------
 
 const Token *Token::findmatch(const Token *tok, const char pattern[], unsigned int varId)

lib/token.h

@@ -274,6 +274,15 @@ public:
      */
     std::string strValue() const;
 
+    /**
+     * Move srcStart and srcEnd tokens and all tokens between then
+     * into new a location. Only links between tokens are changed.
+     * @param srcStart This is the first token to be moved
+     * @param srcEnd The last token to be moved
+     * @param newLocation srcStart will be placed after this token.
+     */
+    static void move(Token *srcStart, Token *srcEnd, Token *newLocation);
+
 private:
     void next(Token *next)
     {

lib/tokenize.cpp

@@ -3983,9 +3983,6 @@ void Tokenizer::simplifyNestedStrcat()
             continue;
         }
 
-        // insert extracted function calls before first strcat call
-        Token *insertPos = tok;
-
         // find inner strcat call
         Token *tok2 = tok->tokAt(3);
         while (Token::simpleMatch(tok2, "strcat ( strcat"))
@@ -3993,52 +3990,21 @@ void Tokenizer::simplifyNestedStrcat()
             tok2 = tok2->tokAt(2);
         }
 
-        Token *end   = tok2->next()->link()->next();
-        Token *endOfFirstArg = NULL;
-        std::stack<Token *> brackets;
-        unsigned int lineno = tok->next()->linenr();
+        // If we have this code:
+        //   strcat(strcat(dst, foo), bar);
+        // We move this part of code before all strcat() calls: strcat(dst, foo)
+        // And place "dst" token where the code was.
+        Token *prevTok = tok2->previous();
 
-        // copy tokens to new place
-        for (Token *cur = tok2; cur != end; cur = cur->next())
-        {
-            insertPos->insertToken(cur->strAt(0));
-            insertPos = insertPos->next();
+        // Move tokens to new place
+        Token::move(tok2, tok2->next()->link(), tok);
+        tok = tok2->next()->link();
 
-            if (cur->str() == "," && endOfFirstArg == NULL)
-            {
-                endOfFirstArg = cur;
-            }
+        // Insert the "dst" token
+        prevTok->insertToken(tok2->strAt(2));
 
-            // preserve varId
-            if (cur->varId())
-            {
-                insertPos->varId(cur->varId());
-            }
-
-            // use line number of first strcat token for all new
-            // tokens
-            insertPos->linenr(lineno);
-
-            // linkify braces
-            if (insertPos->str() == "(")
-            {
-                brackets.push(insertPos);
-            }
-            else if (insertPos->str() == ")")
-            {
-                Token::createMutualLinks(brackets.top(), insertPos);
-                brackets.pop();
-            }
-        }
-        insertPos->insertToken(";");
-
-        // remove tokens at old place, but don't remove token with
-        // variable name (1st argument)
-        Token::eraseTokens(tok2->previous(), tok2->tokAt(2));
-        Token::eraseTokens(endOfFirstArg->previous(), end);
-
-        // skip just inserted tokens
-        tok = insertPos;
+        // Insert semicolon after the moved strcat()
+        tok->insertToken(";");
     }
 
 }

test/testsimplifytokens.cpp

@@ -124,6 +124,7 @@ private:
 
         // Simplify nested strcat() calls
         TEST_CASE(strcat1);
+        TEST_CASE(strcat2);
 
         // Syntax error
         TEST_CASE(argumentsWithSameName)
@@ -1940,6 +1941,15 @@ private:
 
         ASSERT_EQUALS(expect, tok(code));
     }
+    void strcat2()
+    {
+        const char code[] = "; strcat(strcat(dst, foo[0]), \" \");";
+        const char expect[] = "; "
+                              "strcat ( dst , foo [ 0 ] ) ; "
+                              "strcat ( dst , \" \" ) ;";
+
+        ASSERT_EQUALS(expect, tok(code));
+    }
 
     void argumentsWithSameName()
     {