simplify tokens: simplify known variable value handles ++ and -- better

src/tokenize.cpp

@@ -1604,6 +1604,22 @@ bool Tokenizer::simplifyFunctionReturn()
     return ret;
 }
 
+
+static void incdec(std::string &value, const std::string &op)
+{
+    int ivalue = 0;
+    std::istringstream istr(value.c_str());
+    istr >> ivalue;
+    if (op == "++")
+        ++ivalue;
+    else if (op == "--")
+        --ivalue;
+    std::ostringstream ostr;
+    ostr << ivalue;
+    value = ostr.str();
+}
+
+
 bool Tokenizer::simplifyKnownVariables()
 {
     bool ret = false;
@@ -1635,6 +1651,8 @@ bool Tokenizer::simplifyKnownVariables()
                 if (varid == 0)
                     continue;
 
+                std::string value(tok2->strAt(2));
+
                 for (Token *tok3 = tok2->next(); tok3; tok3 = tok3->next())
                 {
                     // Perhaps it's a loop => bail out
@@ -1649,7 +1667,7 @@ bool Tokenizer::simplifyKnownVariables()
                     if (Token::Match(tok3, "if ( %varid% )", varid))
                     {
                         tok3 = tok3->next()->next();
-                        tok3->str(tok2->strAt(2));
+                        tok3->str(value.c_str());
                         ret = true;
                     }
 
@@ -1657,9 +1675,25 @@ bool Tokenizer::simplifyKnownVariables()
                     if (Token::Match(tok3, "[=+-*/[] %varid% [+-*/;]]", varid))
                     {
                         tok3 = tok3->next();
-                        tok3->str(tok2->strAt(2));
+                        tok3->str(value.c_str());
                         ret = true;
                     }
+
+                    if (Token::Match(tok3->next(), "%varid% ++|--", varid))
+                    {
+                        tok3 = tok3->next();
+                        tok3->str(value.c_str());
+                        incdec(value, tok3->strAt(1));
+                        tok3->deleteNext();
+                    }
+
+                    if (Token::Match(tok3->next(), "++|-- %varid%", varid))
+                    {
+                        incdec(value, tok3->strAt(1));
+                        tok3->deleteNext();
+                        tok3 = tok3->next();
+                        tok3->str(value.c_str());
+                    }
                 }
             }
         }

test/testtokenize.cpp

@@ -84,6 +84,7 @@ private:
         TEST_CASE(simplifyKnownVariables4);
         TEST_CASE(simplifyKnownVariables5);
         TEST_CASE(simplifyKnownVariables6);
+        TEST_CASE(simplifyKnownVariables7);
 
         TEST_CASE(multiCompare);
 
@@ -534,6 +535,30 @@ private:
         ASSERT_EQUALS(std::string(" void f ( ) { char str [ 2 ] ; int a = 4 ; str [ 4 ] = 0 ; }"), ostr.str());
     }
 
+    void simplifyKnownVariables7()
+    {
+        const char code[] = "void foo()\n"
+                            "{\n"
+                            "    int i = 22;\n"
+                            "    abc[i++] = 1;\n"
+                            "    abc[++i] = 2;\n"
+                            "}\n";
+        // tokenize..
+        OurTokenizer tokenizer;
+        std::istringstream istr(code);
+        tokenizer.tokenize(istr, "test.cpp");
+
+        tokenizer.setVarId();
+        tokenizer.simplifyKnownVariables();
+
+        std::ostringstream ostr;
+        for (const Token *tok = tokenizer.tokens(); tok; tok = tok->next())
+            ostr << " " << tok->str();
+        ASSERT_EQUALS(std::string(" void foo ( ) { int i = 22 ; abc [ 22 ] = 1 ; abc [ 24 ] = 2 ; }"), ostr.str());
+    }
+
+
+
     void multiCompare()
     {
         // Test for found