CheckBufferOverrun: Fixed minsize checking of string literals. Check sizeof string instead of strlen.

lib/checkbufferoverrun.cpp

@@ -1540,7 +1540,13 @@ void CheckBufferOverrun::checkStringArgument()
                 const std::list<Library::ArgumentChecks::MinSize> *minsizes = _settings->library.argminsizes(tok->str(), argnr);
                 if (!minsizes)
                     continue;
-                if (checkMinSizes(*minsizes, tok, Token::getStrLength(argtok)+1U, nullptr))
+                unsigned int sizeofstring = 1;
+                for (unsigned int i = 0U; i < argtok->str().size(); i++) {
+                    if (argtok->str()[i] == '\\')
+                        ++i;
+                    ++sizeofstring;
+                }
+                if (checkMinSizes(*minsizes, tok, sizeofstring, nullptr))
                     bufferOverrunError(argtok);
             }
         }

test/testbufferoverrun.cpp

@@ -3272,6 +3272,12 @@ private:
                  "memcpy (&str2,str1,15);\n" // <-- strlen(str1) + 1 = 15
                  "}");
         ASSERT_EQUALS("[test.cpp:4]: (error) Buffer is accessed out of bounds: str1\n", errout.str());
+
+        checkstd("void f() { \n"
+                 "  char str[5];\n"
+                 "  memcpy (str, \"\\0\\0\\0\\0\\0\", 5);\n"
+                 "}");
+        ASSERT_EQUALS("", errout.str());
     }
 
     void varid1() {