/*
 * Cppcheck - A tool for static C/C++ code analysis
 * Copyright (C) 2007-2019 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) OVERRIDE {
 CheckString checkString(tokenizer, settings, errorLogger);

 // Checks
 checkString.strPlusChar();
 checkString.checkSuspiciousStringCompare();
 checkString.stringLiteralWrite();
 checkString.overlappingStrcmp();
 checkString.checkIncorrectStringCompare();
 checkString.sprintfOverlappingData();
 checkString.checkAlwaysTrueOrFalseStringCompare();
 }

 /** @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 *funcTok, 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, bool isLong);
 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 OVERRIDE {
 CheckString c(nullptr, settings, errorLogger);

 c.stringLiteralWriteError(nullptr, nullptr);
 c.sprintfOverlappingDataError(nullptr, nullptr, "varname");
 c.strPlusCharError(nullptr);
 c.incorrectStringCompareError(nullptr, "substr", "\"Hello World\"");
 c.suspiciousStringCompareError(nullptr, "foo", false);
 c.suspiciousStringCompareError_char(nullptr, "foo");
 c.incorrectStringBooleanError(nullptr, "\"Hello World\"");
 c.incorrectStringBooleanError(nullptr, "\'x\'");
 c.alwaysTrueFalseStringCompareError(nullptr, "str1", "str2");
 c.alwaysTrueStringVariableCompareError(nullptr, "varname1", "varname2");
 c.overlappingStrcmpError(nullptr, nullptr);
 }

 static std::string myName() {
 return "String";
 }

 std::string classInfo() const OVERRIDE {
 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/char 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