/*

 * Cppcheck - A tool for static C/C++ code analysis

 * Copyright (C) 2007-2018 Cppcheck team.

 *

 * This program is free software: you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation, either version 3 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program.  If not, see <http://www.gnu.org/licenses/>.

 */

//---------------------------------------------------------------------------

#ifndef checkstringH

#define checkstringH

//---------------------------------------------------------------------------

#include "check.h"

#include "config.h"

#include <string>

class ErrorLogger;

class Settings;

class Token;

class Tokenizer;

/// @addtogroup Checks

/// @{

/** @brief Detect misusage of C-style strings and related standard functions */

class CPPCHECKLIB CheckString : public Check {

public:

    /** @brief This constructor is used when registering the CheckClass */

    CheckString() : Check(myName()) {

    }

    /** @brief This constructor is used when running checks. */

    CheckString(const Tokenizer *tokenizer, const Settings *settings, ErrorLogger *errorLogger)

        : Check(myName(), tokenizer, settings, errorLogger) {

    }

    /** @brief Run checks against the normal token list */

    void runChecks(const Tokenizer *tokenizer, const Settings *settings, ErrorLogger *errorLogger) {

        CheckString checkString(tokenizer, settings, errorLogger);

        // Checks

        checkString.strPlusChar();

        checkString.checkSuspiciousStringCompare();

        checkString.stringLiteralWrite();

        checkString.overlappingStrcmp();

    }

    /** @brief Run checks against the simplified token list */

    void runSimplifiedChecks(const Tokenizer *tokenizer, const Settings *settings, ErrorLogger *errorLogger) {

        CheckString checkString(tokenizer, settings, errorLogger);

        // Checks

        checkString.checkIncorrectStringCompare();

        checkString.checkAlwaysTrueOrFalseStringCompare();

        checkString.sprintfOverlappingData();

    }

    /** @brief undefined behaviour, writing string literal */

    void stringLiteralWrite();

    /** @brief str plus char (unusual pointer arithmetic) */

    void strPlusChar();

    /** @brief %Check for using bad usage of strncmp and substr */

    void checkIncorrectStringCompare();

    /** @brief %Check for comparison of a string literal with a char* variable */

    void checkSuspiciousStringCompare();

    /** @brief %Check for suspicious code that compares string literals for equality */

    void checkAlwaysTrueOrFalseStringCompare();

    /** @brief %Check for overlapping strcmp() */

    void overlappingStrcmp();

    /** @brief %Check for overlapping source and destination passed to sprintf() */

    void sprintfOverlappingData();

private:

    void stringLiteralWriteError(const Token *tok, const Token *strValue);

    void sprintfOverlappingDataError(const Token *tok, const std::string &varname);

    void strPlusCharError(const Token *tok);

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

    void incorrectStringBooleanError(const Token *tok, const std::string& string);

    void alwaysTrueFalseStringCompareError(const Token *tok, const std::string& str1, const std::string& str2);

    void alwaysTrueStringVariableCompareError(const Token *tok, const std::string& str1, const std::string& str2);

    void suspiciousStringCompareError(const Token* tok, const std::string& var);

    void suspiciousStringCompareError_char(const Token* tok, const std::string& var);

    void overlappingStrcmpError(const Token* eq0, const Token *ne0);

    void getErrorMessages(ErrorLogger *errorLogger, const Settings *settings) const {

        CheckString c(nullptr, settings, errorLogger);

        c.stringLiteralWriteError(nullptr, nullptr);

        c.sprintfOverlappingDataError(nullptr, "varname");

        c.strPlusCharError(nullptr);

        c.incorrectStringCompareError(nullptr, "substr", "\"Hello World\"");

        c.suspiciousStringCompareError(nullptr, "foo");

        c.suspiciousStringCompareError_char(nullptr, "foo");

        c.incorrectStringBooleanError(nullptr, "\"Hello World\"");

        c.alwaysTrueFalseStringCompareError(nullptr, "str1", "str2");

        c.alwaysTrueStringVariableCompareError(nullptr, "varname1", "varname2");

        c.overlappingStrcmpError(nullptr, nullptr);

    }

    static std::string myName() {

        return "String";

    }

    std::string classInfo() const {

        return "Detect misusage of C-style strings:\n"

               "- overlapping buffers passed to sprintf as source and destination\n"

               "- incorrect length arguments for 'substr' and 'strncmp'\n"

               "- suspicious condition (runtime comparison of string literals)\n"

               "- suspicious condition (string literals as boolean)\n"

               "- suspicious comparison of a string literal with a char* variable\n"

               "- suspicious comparison of '\\0' with a char* variable\n"

               "- overlapping strcmp() expression\n";

    }

};

/// @}

//---------------------------------------------------------------------------

#endif // checkstringH