Fix ticket #364 (false positive:: division by zero)

http://apps.sourceforge.net/trac/cppcheck/ticket/364

src/tokenize.cpp

@@ -1465,6 +1465,7 @@ void Tokenizer::simplifyTokenList()
         modified |= removeReduntantConditions();
         modified |= simplifyRedundantParanthesis();
         modified |= simplifyCalculations();
+        modified |= simplifyQuestionMark();
     }
 
     createLinks();
@@ -1840,6 +1841,51 @@ bool Tokenizer::simplifyConditions()
     return ret;
 }
 
+bool Tokenizer::simplifyQuestionMark()
+{
+    bool ret = false;
+    for (Token *tok = _tokens; tok; tok = tok->next())
+    {
+        if (tok->str() != "?")
+            continue;
+
+        if (!tok->previous() || !tok->previous()->previous())
+            continue;
+
+        if (!Token::Match(tok->previous()->previous(), "[=,(]"))
+            continue;
+
+        if (!Token::Match(tok->previous(), "%bool%") &&
+            !Token::Match(tok->previous(), "%num%"))
+            continue;
+
+        if (tok->previous()->str() == "false" ||
+            tok->previous()->str() == "0")
+        {
+            // Use code after semicolon, remove code before it.
+            const Token *end = Token::findmatch(tok, ":");
+            if (!end || !end->next())
+                continue;
+
+            end = end->next();
+            tok = tok->previous();
+            while (tok->next() != end)
+            {
+                tok->deleteNext();
+            }
+
+            Token *temp = tok;
+            tok = tok->next();
+            temp->deleteThis();
+        }
+        else
+        {
+            // Use code before semicolon
+        }
+    }
+
+    return ret;
+}
 
 bool Tokenizer::simplifyCasts()
 {

src/tokenize.h

@@ -100,6 +100,11 @@ public:
      */
     bool simplifyVarDecl();
 
+    /**
+     * Simplify question mark - colon operator
+     * Example: 0 ? (2/0) : 0 => 0
+     */
+    bool simplifyQuestionMark();
 
     /**
      * simplify if-assignments..

test/testother.cpp

@@ -111,10 +111,14 @@ private:
               "    cout<<b/sum;\n"
               "}\n");
         ASSERT_EQUALS("", errout.str());
+
+        check("void foo()\n"
+              "{\n"
+              "    int a = 0 ? (2/0) : 0;\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
     }
 
-
-
     void delete1()
     {
         check("void foo()\n"