Method checkIncorrectStringCompare

lib/checkstring.cpp:275–322

--------------------------------------------------------------------------- Implicit casts of string literals to bool Comparing string literal with strlen() with wrong length ---------------------------------------------------------------------------

// Comparing string literal with strlen() with wrong length
//---------------------------------------------------------------------------
void CheckStringImpl::checkIncorrectStringCompare()
{
    if (!mSettings.severity.isEnabled(Severity::warning))
        return;

    logChecker("CheckString::checkIncorrectStringCompare"); // warning

    const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
    for (const Scope * scope : symbolDatabase->functionScopes) {
        for (const Token* tok = scope->bodyStart->next(); tok != scope->bodyEnd; tok = tok->next()) {
            // skip "assert(str && ..)" and "assert(.. && str)"
            if ((endsWith(tok->str(), "assert") || endsWith(tok->str(), "ASSERT")) &&
                Token::Match(tok, "%name% (") &&
                (Token::Match(tok->tokAt(2), "%str% &&") || Token::Match(tok->linkAt(1)->tokAt(-2), "&& %str% )")))
                tok = tok->linkAt(1);

            if (Token::simpleMatch(tok, ". substr (") && Token::Match(tok->tokAt(3)->nextArgument(), "%num% )")) {
                const MathLib::biguint clen = MathLib::toBigUNumber(tok->linkAt(2)->tokAt(-1));
                const Token* begin = tok->previous();
                for (;;) { // Find start of statement
                    while (begin->link() && Token::Match(begin, "]|)|>"))
                        begin = begin->link()->previous();
                    if (Token::Match(begin->previous(), ".|::"))
                        begin = begin->tokAt(-2);
                    else
                        break;
                }
                begin = begin->previous();
                const Token* end = tok->linkAt(2)->next();
                if (Token::Match(begin->previous(), "%str% ==|!=") && begin->strAt(-2) != "+") {
                    const std::size_t slen = Token::getStrLength(begin->previous());
                    if (clen != slen) {
                        incorrectStringCompareError(tok->next(), "substr", begin->strAt(-1));
                    }
                } else if (Token::Match(end, "==|!= %str% !!+")) {
                    const std::size_t slen = Token::getStrLength(end->next());
                    if (clen != slen) {
                        incorrectStringCompareError(tok->next(), "substr", end->strAt(1));
                    }
                }
            } else if (Token::Match(tok, "%str%|%char%") &&
                       !Token::Match(tok->next(), "%name%") &&
                       isUsedAsBool(tok, mSettings) &&
                       !isMacroUsage(tok))
                incorrectStringBooleanError(tok, tok->str());
        }
    }
}

void CheckStringImpl::incorrectStringCompareError(const Token *tok, const std::string& func, const std::string &string)
{