/*
 * simplecpp - A simple and high-fidelity C/C++ preprocessor library
 * Copyright (C) 2016-2022 Daniel Marjamäki.
 *
 * This library is free software: you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation, either
 * version 3 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library.  If not, see <http://www.gnu.org/licenses/>.
 */

#if defined(_WIN32) || defined(__CYGWIN__) || defined(__MINGW32__)
#define SIMPLECPP_WINDOWS
#define NOMINMAX
#endif

#include "simplecpp.h"

#include <algorithm>
#include <cassert>
#include <cctype>
#include <climits>
#include <cstddef>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <exception>
#include <fstream> // IWYU pragma: keep
#include <iostream>
#include <limits>
#include <list>
#include <map>
#include <set>
#include <sstream> // IWYU pragma: keep
#include <stack>
#include <stdexcept>
#include <string>
#if __cplusplus >= 201103L
#ifdef SIMPLECPP_WINDOWS
#include <mutex>
#endif
#include <unordered_map>
#endif
#include <utility>
#include <vector>

#ifdef SIMPLECPP_WINDOWS
#include <windows.h>
#undef ERROR
#endif

#if __cplusplus >= 201103L
#define OVERRIDE override
#define EXPLICIT explicit
#else
#define OVERRIDE
#define EXPLICIT
#endif

#if (__cplusplus < 201103L) && !defined(__APPLE__)
#define nullptr NULL
#endif

static bool isHex(const std::string &s)
{
    return s.size()>2 && (s.compare(0,2,"0x")==0 || s.compare(0,2,"0X")==0);
}

static bool isOct(const std::string &s)
{
    return s.size()>1 && (s[0]=='0') && (s[1] >= '0') && (s[1] < '8');
}

// TODO: added an undercore since this conflicts with a function of the same name in utils.h from Cppcheck source when building Cppcheck with MSBuild
static bool isStringLiteral_(const std::string &s)
{
    return s.size() > 1 && (s[0]=='\"') && (*s.rbegin()=='\"');
}

// TODO: added an undercore since this conflicts with a function of the same name in utils.h from Cppcheck source when building Cppcheck with MSBuild
static bool isCharLiteral_(const std::string &s)
{
    // char literal patterns can include 'a', '\t', '\000', '\xff', 'abcd', and maybe ''
    // This only checks for the surrounding '' but doesn't parse the content.
    return s.size() > 1 && (s[0]=='\'') && (*s.rbegin()=='\'');
}

static const simplecpp::TokenString DEFINE("define");
static const simplecpp::TokenString UNDEF("undef");

static const simplecpp::TokenString INCLUDE("include");

static const simplecpp::TokenString ERROR("error");
static const simplecpp::TokenString WARNING("warning");

static const simplecpp::TokenString IF("if");
static const simplecpp::TokenString IFDEF("ifdef");
static const simplecpp::TokenString IFNDEF("ifndef");
static const simplecpp::TokenString DEFINED("defined");
static const simplecpp::TokenString ELSE("else");
static const simplecpp::TokenString ELIF("elif");
static const simplecpp::TokenString ENDIF("endif");

static const simplecpp::TokenString PRAGMA("pragma");
static const simplecpp::TokenString ONCE("once");

static const simplecpp::TokenString HAS_INCLUDE("__has_include");

template<class T> static std::string toString(T t)
{
    // NOLINTNEXTLINE(misc-const-correctness) - false positive
    std::ostringstream ostr;
    ostr << t;
    return ostr.str();
}

static long long stringToLL(const std::string &s)
{
    long long ret;
    const bool hex = isHex(s);
    const bool oct = isOct(s);
    std::istringstream istr(hex ? s.substr(2) : oct ? s.substr(1) : s);
    if (hex)
        istr >> std::hex;
    else if (oct)
        istr >> std::oct;
    istr >> ret;
    return ret;
}

static unsigned long long stringToULL(const std::string &s)
{
    unsigned long long ret;
    const bool hex = isHex(s);
    const bool oct = isOct(s);
    std::istringstream istr(hex ? s.substr(2) : oct ? s.substr(1) : s);
    if (hex)
        istr >> std::hex;
    else if (oct)
        istr >> std::oct;
    istr >> ret;
    return ret;
}

static bool endsWith(const std::string &s, const std::string &e)
{
    return (s.size() >= e.size()) && std::equal(e.rbegin(), e.rend(), s.rbegin());
}

static bool sameline(const simplecpp::Token *tok1, const simplecpp::Token *tok2)
{
    return tok1 && tok2 && tok1->location.sameline(tok2->location);
}

static bool isAlternativeBinaryOp(const simplecpp::Token *tok, const std::string &alt)
{
    return (tok->name &&
            tok->str() == alt &&
            tok->previous &&
            tok->next &&
            (tok->previous->number || tok->previous->name || tok->previous->op == ')') &&
            (tok->next->number || tok->next->name || tok->next->op == '('));
}

static bool isAlternativeUnaryOp(const simplecpp::Token *tok, const std::string &alt)
{
    return ((tok->name && tok->str() == alt) &&
            (!tok->previous || tok->previous->op == '(') &&
            (tok->next && (tok->next->name || tok->next->number)));
}

static std::string replaceAll(std::string s, const std::string& from, const std::string& to)
{
    for (size_t pos = s.find(from); pos != std::string::npos; pos = s.find(from, pos + to.size()))
        s.replace(pos, from.size(), to);
    return s;
}

const std::string simplecpp::Location::emptyFileName;

void simplecpp::Location::adjust(const std::string &str)
{
    if (strpbrk(str.c_str(), "\r\n") == nullptr) {
        col += str.size();
        return;
    }

    for (std::size_t i = 0U; i < str.size(); ++i) {
        col++;
        if (str[i] == '\n' || str[i] == '\r') {
            col = 1;
            line++;
            if (str[i] == '\r' && (i+1)<str.size() && str[i+1]=='\n')
                ++i;
        }
    }
}

bool simplecpp::Token::isOneOf(const char ops[]) const
{
    return (op != '\0') && (std::strchr(ops, op) != nullptr);
}

bool simplecpp::Token::startsWithOneOf(const char c[]) const
{
    return std::strchr(c, string[0]) != nullptr;
}

bool simplecpp::Token::endsWithOneOf(const char c[]) const
{
    return std::strchr(c, string[string.size() - 1U]) != nullptr;
}

void simplecpp::Token::printAll() const
{
    const Token *tok = this;
    while (tok->previous)
        tok = tok->previous;
    for (; tok; tok = tok->next) {
        if (tok->previous) {
            std::cout << (sameline(tok, tok->previous) ? ' ' : '\n');
        }
        std::cout << tok->str();
    }
    std::cout << std::endl;
}

void simplecpp::Token::printOut() const
{
    for (const Token *tok = this; tok; tok = tok->next) {
        if (tok != this) {
            std::cout << (sameline(tok, tok->previous) ? ' ' : '\n');
        }
        std::cout << tok->str();
    }
    std::cout << std::endl;
}

// cppcheck-suppress noConstructor - we call init() in the inherited to initialize the private members
class simplecpp::TokenList::Stream {
public:
    virtual ~Stream() {}

    virtual int get() = 0;
    virtual int peek() = 0;
    virtual void unget() = 0;
    virtual bool good() = 0;

    unsigned char readChar()
    {
        unsigned char ch = static_cast<unsigned char>(get());

        // For UTF-16 encoded files the BOM is 0xfeff/0xfffe. If the
        // character is non-ASCII character then replace it with 0xff
        if (isUtf16) {
            const unsigned char ch2 = static_cast<unsigned char>(get());
            const int ch16 = makeUtf16Char(ch, ch2);
            ch = static_cast<unsigned char>(((ch16 >= 0x80) ? 0xff : ch16));
        }

        // Handling of newlines..
        if (ch == '\r') {
            ch = '\n';

            int ch2 = get();
            if (isUtf16) {
                const int c2 = get();
                ch2 = makeUtf16Char(ch2, c2);
            }

            if (ch2 != '\n')
                ungetChar();
        }

        return ch;
    }

    unsigned char peekChar()
    {
        unsigned char ch = static_cast<unsigned char>(peek());

        // For UTF-16 encoded files the BOM is 0xfeff/0xfffe. If the
        // character is non-ASCII character then replace it with 0xff
        if (isUtf16) {
            (void)get();
            const unsigned char ch2 = static_cast<unsigned char>(peek());
            unget();
            const int ch16 = makeUtf16Char(ch, ch2);
            ch = static_cast<unsigned char>(((ch16 >= 0x80) ? 0xff : ch16));
        }

        // Handling of newlines..
        if (ch == '\r')
            ch = '\n';

        return ch;
    }

    void ungetChar()
    {
        unget();
        if (isUtf16)
            unget();
    }

protected:
    void init() {
        // initialize since we use peek() in getAndSkipBOM()
        isUtf16 = false;
        bom = getAndSkipBOM();
        isUtf16 = (bom == 0xfeff || bom == 0xfffe);
    }

private:
    inline int makeUtf16Char(const unsigned char ch, const unsigned char ch2) const
    {
        return (bom == 0xfeff) ? (ch<<8 | ch2) : (ch2<<8 | ch);
    }

    unsigned short getAndSkipBOM()
    {
        const int ch1 = peek();

        // The UTF-16 BOM is 0xfffe or 0xfeff.
        if (ch1 >= 0xfe) {
            (void)get();
            const unsigned short byte = (static_cast<unsigned char>(ch1) << 8);
            if (peek() >= 0xfe)
                return byte | static_cast<unsigned char>(get());
            unget();
            return 0;
        }

        // Skip UTF-8 BOM 0xefbbbf
        if (ch1 == 0xef) {
            (void)get();
            if (peek() == 0xbb) {
                (void)get();
                if (peek() == 0xbf) {
                    (void)get();
                    return 0;
                }
                unget();
            }
            unget();
        }

        return 0;
    }

    unsigned short bom;
protected:
    bool isUtf16;
};

class StdIStream : public simplecpp::TokenList::Stream {
public:
    // cppcheck-suppress uninitDerivedMemberVar - we call Stream::init() to initialize the private members
    EXPLICIT StdIStream(std::istream &istr)
        : istr(istr)
    {
        assert(istr.good());
        init();
    }

    virtual int get() OVERRIDE {
        return istr.get();
    }
    virtual int peek() OVERRIDE {
        return istr.peek();
    }
    virtual void unget() OVERRIDE {
        istr.unget();
    }
    virtual bool good() OVERRIDE {
        return istr.good();
    }

private:
    std::istream &istr;
};

class FileStream : public simplecpp::TokenList::Stream {
public:
    // cppcheck-suppress uninitDerivedMemberVar - we call Stream::init() to initialize the private members
    EXPLICIT FileStream(const std::string &filename)
        : file(fopen(filename.c_str(), "rb"))
        , lastCh(0)
        , lastStatus(0)
    {
        assert(file != nullptr);
        init();
    }

    ~FileStream() OVERRIDE {
        fclose(file);
        file = nullptr;
    }

    virtual int get() OVERRIDE {
        lastStatus = lastCh = fgetc(file);
        return lastCh;
    }
    virtual int peek() OVERRIDE{
        // keep lastCh intact
        const int ch = fgetc(file);
        unget_internal(ch);
        return ch;
    }
    virtual void unget() OVERRIDE {
        unget_internal(lastCh);
    }
    virtual bool good() OVERRIDE {
        return lastStatus != EOF;
    }

private:
    void unget_internal(int ch) {
        if (isUtf16) {
            // TODO: use ungetc() as well
            // UTF-16 has subsequent unget() calls
            fseek(file, -1, SEEK_CUR);
        }
        else
            ungetc(ch, file);
    }

    FileStream(const FileStream&);
    FileStream &operator=(const FileStream&);

    FILE *file;
    int lastCh;
    int lastStatus;
};

simplecpp::TokenList::TokenList(std::vector<std::string> &filenames) : frontToken(nullptr), backToken(nullptr), files(filenames) {}

simplecpp::TokenList::TokenList(std::istream &istr, std::vector<std::string> &filenames, const std::string &filename, OutputList *outputList)
    : frontToken(nullptr), backToken(nullptr), files(filenames)
{
    StdIStream stream(istr);
    readfile(stream,filename,outputList);
}

simplecpp::TokenList::TokenList(const std::string &filename, std::vector<std::string> &filenames, OutputList *outputList)
        : frontToken(nullptr), backToken(nullptr), files(filenames)
{
    FileStream stream(filename);
    readfile(stream,filename,outputList);
}

simplecpp::TokenList::TokenList(const TokenList &other) : frontToken(nullptr), backToken(nullptr), files(other.files)
{
    *this = other;
}

#if __cplusplus >= 201103L
simplecpp::TokenList::TokenList(TokenList &&other) : frontToken(nullptr), backToken(nullptr), files(other.files)
{
    *this = std::move(other);
}
#endif

simplecpp::TokenList::~TokenList()
{
    clear();
}

simplecpp::TokenList &simplecpp::TokenList::operator=(const TokenList &other)
{
    if (this != &other) {
        clear();
        files = other.files;
        for (const Token *tok = other.cfront(); tok; tok = tok->next)
            push_back(new Token(*tok));
        sizeOfType = other.sizeOfType;
    }
    return *this;
}

#if __cplusplus >= 201103L
simplecpp::TokenList &simplecpp::TokenList::operator=(TokenList &&other)
{
    if (this != &other) {
        clear();
        frontToken = other.frontToken;
        other.frontToken = nullptr;
        backToken = other.backToken;
        other.backToken = nullptr;
        files = other.files;
        sizeOfType = std::move(other.sizeOfType);
    }
    return *this;
}
#endif

void simplecpp::TokenList::clear()
{
    backToken = nullptr;
    while (frontToken) {
        Token * const next = frontToken->next;
        delete frontToken;
        frontToken = next;
    }
    sizeOfType.clear();
}

void simplecpp::TokenList::push_back(Token *tok)
{
    if (!frontToken)
        frontToken = tok;
    else
        backToken->next = tok;
    tok->previous = backToken;
    backToken = tok;
}

void simplecpp::TokenList::dump() const
{
    std::cout << stringify() << std::endl;
}

std::string simplecpp::TokenList::stringify() const
{
    std::ostringstream ret;
    Location loc(files);
    for (const Token *tok = cfront(); tok; tok = tok->next) {
        if (tok->location.line < loc.line || tok->location.fileIndex != loc.fileIndex) {
            ret << "\n#line " << tok->location.line << " \"" << tok->location.file() << "\"\n";
            loc = tok->location;
        }

        while (tok->location.line > loc.line) {
            ret << '\n';
            loc.line++;
        }

        if (sameline(tok->previous, tok))
            ret << ' ';

        ret << tok->str();

        loc.adjust(tok->str());
    }

    return ret.str();
}

static bool isNameChar(unsigned char ch)
{
    return std::isalnum(ch) || ch == '_' || ch == '$';
}

static std::string escapeString(const std::string &str)
{
    std::ostringstream ostr;
    ostr << '\"';
    for (std::size_t i = 1U; i < str.size() - 1; ++i) {
        const char c = str[i];
        if (c == '\\' || c == '\"' || c == '\'')
            ostr << '\\';
        ostr << c;
    }
    ostr << '\"';
    return ostr.str();
}

static void portabilityBackslash(simplecpp::OutputList *outputList, const std::vector<std::string> &files, const simplecpp::Location &location)
{
    if (!outputList)
        return;
    simplecpp::Output err(files);
    err.type = simplecpp::Output::PORTABILITY_BACKSLASH;
    err.location = location;
    err.msg = "Combination 'backslash space newline' is not portable.";
    outputList->push_back(err);
}

static bool isStringLiteralPrefix(const std::string &str)
{
    return str == "u" || str == "U" || str == "L" || str == "u8" ||
           str == "R" || str == "uR" || str == "UR" || str == "LR" || str == "u8R";
}

void simplecpp::TokenList::lineDirective(unsigned int fileIndex, unsigned int line, Location *location)
{
    if (fileIndex != location->fileIndex || line >= location->line) {
        location->fileIndex = fileIndex;
        location->line = line;
        return;
    }

    if (line + 2 >= location->line) {
        location->line = line;
        while (cback()->op != '#')
            deleteToken(back());
        deleteToken(back());
        return;
    }
}

static const std::string COMMENT_END("*/");

void simplecpp::TokenList::readfile(Stream &stream, const std::string &filename, OutputList *outputList)
{
    std::stack<simplecpp::Location> loc;

    unsigned int multiline = 0U;

    const Token *oldLastToken = nullptr;

    Location location(files);
    location.fileIndex = fileIndex(filename);
    location.line = 1U;
    location.col  = 1U;
    while (stream.good()) {
        unsigned char ch = stream.readChar();
        if (!stream.good())
            break;
        if (ch < ' ' && ch != '\t' && ch != '\n' && ch != '\r')
            ch = ' ';

        if (ch >= 0x80) {
            if (outputList) {
                simplecpp::Output err(files);
                err.type = simplecpp::Output::UNHANDLED_CHAR_ERROR;
                err.location = location;
                std::ostringstream s;
                s << static_cast<int>(ch);
                err.msg = "The code contains unhandled character(s) (character code=" + s.str() + "). Neither unicode nor extended ascii is supported.";
                outputList->push_back(err);
            }
            clear();
            return;
        }

        if (ch == '\n') {
            if (cback() && cback()->op == '\\') {
                if (location.col > cback()->location.col + 1U)
                    portabilityBackslash(outputList, files, cback()->location);
                ++multiline;
                deleteToken(back());
            } else {
                location.line += multiline + 1;
                multiline = 0U;
            }
            if (!multiline)
                location.col = 1;

            if (oldLastToken != cback()) {
                oldLastToken = cback();
                if (!isLastLinePreprocessor())
                    continue;
                const std::string lastline(lastLine());
                if (lastline == "# file %str%") {
                    const Token *strtok = cback();
                    while (strtok->comment)
                        strtok = strtok->previous;
                    loc.push(location);
                    location.fileIndex = fileIndex(strtok->str().substr(1U, strtok->str().size() - 2U));
                    location.line = 1U;
                } else if (lastline == "# line %num%") {
                    const Token *numtok = cback();
                    while (numtok->comment)
                        numtok = numtok->previous;
                    lineDirective(location.fileIndex, std::atol(numtok->str().c_str()), &location);
                } else if (lastline == "# %num% %str%" || lastline == "# line %num% %str%") {
                    const Token *strtok = cback();
                    while (strtok->comment)
                        strtok = strtok->previous;
                    const Token *numtok = strtok->previous;
                    while (numtok->comment)
                        numtok = numtok->previous;
                    lineDirective(fileIndex(replaceAll(strtok->str().substr(1U, strtok->str().size() - 2U),"\\\\","\\")),
                                  std::atol(numtok->str().c_str()), &location);
                }
                // #endfile
                else if (lastline == "# endfile" && !loc.empty()) {
                    location = loc.top();
                    loc.pop();
                }
            }

            continue;
        }

        if (std::isspace(ch)) {
            location.col++;
            continue;
        }

        TokenString currentToken;

        if (cback() && cback()->location.line == location.line && cback()->previous && cback()->previous->op == '#' && isLastLinePreprocessor() && (lastLine() == "# error" || lastLine() == "# warning")) {
            char prev = ' ';
            while (stream.good() && (prev == '\\' || (ch != '\r' && ch != '\n'))) {
                currentToken += ch;
                prev = ch;
                ch = stream.readChar();
            }
            stream.ungetChar();
            push_back(new Token(currentToken, location));
            location.adjust(currentToken);
            continue;
        }

        // number or name
        if (isNameChar(ch)) {
            const bool num = std::isdigit(ch);
            while (stream.good() && isNameChar(ch)) {
                currentToken += ch;
                ch = stream.readChar();
                if (num && ch=='\'' && isNameChar(stream.peekChar()))
                    ch = stream.readChar();
            }

            stream.ungetChar();
        }

        // comment
        else if (ch == '/' && stream.peekChar() == '/') {
            while (stream.good() && ch != '\r' && ch != '\n') {
                currentToken += ch;
                ch = stream.readChar();
            }
            const std::string::size_type pos = currentToken.find_last_not_of(" \t");
            if (pos < currentToken.size() - 1U && currentToken[pos] == '\\')
                portabilityBackslash(outputList, files, location);
            if (currentToken[currentToken.size() - 1U] == '\\') {
                ++multiline;
                currentToken.erase(currentToken.size() - 1U);
            } else {
                stream.ungetChar();
            }
        }

        // comment
        else if (ch == '/' && stream.peekChar() == '*') {
            currentToken = "/*";
            (void)stream.readChar();
            ch = stream.readChar();
            while (stream.good()) {
                currentToken += ch;
                if (currentToken.size() >= 4U && endsWith(currentToken, COMMENT_END))
                    break;
                ch = stream.readChar();
            }
            // multiline..

            std::string::size_type pos = 0;
            while ((pos = currentToken.find("\\\n",pos)) != std::string::npos) {
                currentToken.erase(pos,2);
                ++multiline;
            }
            if (multiline || isLastLinePreprocessor()) {
                pos = 0;
                while ((pos = currentToken.find('\n',pos)) != std::string::npos) {
                    currentToken.erase(pos,1);
                    ++multiline;
                }
            }
        }

        // string / char literal
        else if (ch == '\"' || ch == '\'') {
            std::string prefix;
            if (cback() && cback()->name && isStringLiteralPrefix(cback()->str()) &&
                ((cback()->location.col + cback()->str().size()) == location.col) &&
                (cback()->location.line == location.line)) {
                prefix = cback()->str();
            }
            // C++11 raw string literal
            if (ch == '\"' && !prefix.empty() && *cback()->str().rbegin() == 'R') {
                std::string delim;
                currentToken = ch;
                prefix.resize(prefix.size() - 1);
                ch = stream.readChar();
                while (stream.good() && ch != '(' && ch != '\n') {
                    delim += ch;
                    ch = stream.readChar();
                }
                if (!stream.good() || ch == '\n') {
                    if (outputList) {
                        Output err(files);
                        err.type = Output::SYNTAX_ERROR;
                        err.location = location;
                        err.msg = "Invalid newline in raw string delimiter.";
                        outputList->push_back(err);
                    }
                    return;
                }
                const std::string endOfRawString(')' + delim + currentToken);
                while (stream.good() && !(endsWith(currentToken, endOfRawString) && currentToken.size() > 1))
                    currentToken += stream.readChar();
                if (!endsWith(currentToken, endOfRawString)) {
                    if (outputList) {
                        Output err(files);
                        err.type = Output::SYNTAX_ERROR;
                        err.location = location;
                        err.msg = "Raw string missing terminating delimiter.";
                        outputList->push_back(err);
                    }
                    return;
                }
                currentToken.erase(currentToken.size() - endOfRawString.size(), endOfRawString.size() - 1U);
                currentToken = escapeString(currentToken);
                currentToken.insert(0, prefix);
                back()->setstr(currentToken);
                location.adjust(currentToken);
                if (currentToken.find_first_of("\r\n") == std::string::npos)
                    location.col += 2 + 2 * delim.size();
                else
                    location.col += 1 + delim.size();

                continue;
            }

            currentToken = readUntil(stream,location,ch,ch,outputList);
            if (currentToken.size() < 2U)
                // Error is reported by readUntil()
                return;

            std::string s = currentToken;
            std::string::size_type pos;
            int newlines = 0;
            while ((pos = s.find_first_of("\r\n")) != std::string::npos) {
                s.erase(pos,1);
                newlines++;
            }

            if (prefix.empty())
                push_back(new Token(s, location)); // push string without newlines
            else
                back()->setstr(prefix + s);

            if (newlines > 0 && isLastLinePreprocessor() && lastLine().compare(0,9,"# define ") == 0) {
                multiline += newlines;
                location.adjust(s);
            } else {
                location.adjust(currentToken);
            }
            continue;
        }

        else {
            currentToken += ch;
        }

        if (*currentToken.begin() == '<' && isLastLinePreprocessor() && lastLine() == "# include") {
            currentToken = readUntil(stream, location, '<', '>', outputList);
            if (currentToken.size() < 2U)
                return;
        }

        push_back(new Token(currentToken, location));

        if (multiline)
            location.col += currentToken.size();
        else
            location.adjust(currentToken);
    }

    combineOperators();
}

void simplecpp::TokenList::constFold()
{
    while (cfront()) {
        // goto last '('
        Token *tok = back();
        while (tok && tok->op != '(')
            tok = tok->previous;

        // no '(', goto first token
        if (!tok)
            tok = front();

        // Constant fold expression
        constFoldUnaryNotPosNeg(tok);
        constFoldMulDivRem(tok);
        constFoldAddSub(tok);
        constFoldShift(tok);
        constFoldComparison(tok);
        constFoldBitwise(tok);
        constFoldLogicalOp(tok);
        constFoldQuestionOp(&tok);

        // If there is no '(' we are done with the constant folding
        if (tok->op != '(')
            break;

        if (!tok->next || !tok->next->next || tok->next->next->op != ')')
            break;

        tok = tok->next;
        deleteToken(tok->previous);
        deleteToken(tok->next);
    }
}

static bool isFloatSuffix(const simplecpp::Token *tok)
{
    if (!tok || tok->str().size() != 1U)
        return false;
    const char c = std::tolower(tok->str()[0]);
    return c == 'f' || c == 'l';
}

void simplecpp::TokenList::combineOperators()
{
    std::stack<bool> executableScope;
    executableScope.push(false);
    for (Token *tok = front(); tok; tok = tok->next) {
        if (tok->op == '{') {
            if (executableScope.top()) {
                executableScope.push(true);
                continue;
            }
            const Token *prev = tok->previous;
            while (prev && prev->isOneOf(";{}()"))
                prev = prev->previous;
            executableScope.push(prev && prev->op == ')');
            continue;
        }
        if (tok->op == '}') {
            if (executableScope.size() > 1)
                executableScope.pop();
            continue;
        }

        if (tok->op == '.') {
            // ellipsis ...
            if (tok->next && tok->next->op == '.' && tok->next->location.col == (tok->location.col + 1) &&
                tok->next->next && tok->next->next->op == '.' && tok->next->next->location.col == (tok->location.col + 2)) {
                tok->setstr("...");
                deleteToken(tok->next);
                deleteToken(tok->next);
                continue;
            }
            // float literals..
            if (tok->previous && tok->previous->number && sameline(tok->previous, tok)) {
                tok->setstr(tok->previous->str() + '.');
                deleteToken(tok->previous);
                if (isFloatSuffix(tok->next) || (tok->next && tok->next->startsWithOneOf("AaBbCcDdEeFfPp"))) {
                    tok->setstr(tok->str() + tok->next->str());
                    deleteToken(tok->next);
                }
            }
            if (tok->next && tok->next->number) {
                tok->setstr(tok->str() + tok->next->str());
                deleteToken(tok->next);
            }
        }
        // match: [0-9.]+E [+-] [0-9]+
        const char lastChar = tok->str()[tok->str().size() - 1];
        if (tok->number && !isOct(tok->str()) &&
            ((!isHex(tok->str()) && (lastChar == 'E' || lastChar == 'e')) ||
             (isHex(tok->str()) && (lastChar == 'P' || lastChar == 'p'))) &&
            tok->next && tok->next->isOneOf("+-") && tok->next->next && tok->next->next->number) {
            tok->setstr(tok->str() + tok->next->op + tok->next->next->str());
            deleteToken(tok->next);
            deleteToken(tok->next);
        }

        if (tok->op == '\0' || !tok->next || tok->next->op == '\0')
            continue;
        if (!sameline(tok,tok->next))
            continue;
        if (tok->location.col + 1U != tok->next->location.col)
            continue;

        if (tok->next->op == '=' && tok->isOneOf("=!<>+-*/%&|^")) {
            if (tok->op == '&' && !executableScope.top()) {
                // don't combine &= if it is a anonymous reference parameter with default value:
                // void f(x&=2)
                int indentlevel = 0;
                const Token *start = tok;
                while (indentlevel >= 0 && start) {
                    if (start->op == ')')
                        ++indentlevel;
                    else if (start->op == '(')
                        --indentlevel;
                    else if (start->isOneOf(";{}"))
                        break;
                    start = start->previous;
                }
                if (indentlevel == -1 && start) {
                    const Token * const ftok = start;
                    bool isFuncDecl = ftok->name;
                    while (isFuncDecl) {
                        if (!start->name && start->str() != "::" && start->op != '*' && start->op != '&')
                            isFuncDecl = false;
                        if (!start->previous)
                            break;
                        if (start->previous->isOneOf(";{}:"))
                            break;
                        start = start->previous;
                    }
                    isFuncDecl &= start != ftok && start->name;
                    if (isFuncDecl) {
                        // TODO: we could loop through the parameters here and check if they are correct.
                        continue;
                    }
                }
            }
            tok->setstr(tok->str() + "=");
            deleteToken(tok->next);
        } else if ((tok->op == '|' || tok->op == '&') && tok->op == tok->next->op) {
            tok->setstr(tok->str() + tok->next->str());
            deleteToken(tok->next);
        } else if (tok->op == ':' && tok->next->op == ':') {
            tok->setstr(tok->str() + tok->next->str());
            deleteToken(tok->next);
        } else if (tok->op == '-' && tok->next->op == '>') {
            tok->setstr(tok->str() + tok->next->str());
            deleteToken(tok->next);
        } else if ((tok->op == '<' || tok->op == '>') && tok->op == tok->next->op) {
            tok->setstr(tok->str() + tok->next->str());
            deleteToken(tok->next);
            if (tok->next && tok->next->op == '=' && tok->next->next && tok->next->next->op != '=') {
                tok->setstr(tok->str() + tok->next->str());
                deleteToken(tok->next);
            }
        } else if ((tok->op == '+' || tok->op == '-') && tok->op == tok->next->op) {
            if (tok->location.col + 1U != tok->next->location.col)
                continue;
            if (tok->previous && tok->previous->number)
                continue;
            if (tok->next->next && tok->next->next->number)
                continue;
            tok->setstr(tok->str() + tok->next->str());
            deleteToken(tok->next);
        }
    }
}

static const std::string COMPL("compl");
static const std::string NOT("not");
void simplecpp::TokenList::constFoldUnaryNotPosNeg(simplecpp::Token *tok)
{
    for (; tok && tok->op != ')'; tok = tok->next) {
        // "not" might be !
        if (isAlternativeUnaryOp(tok, NOT))
            tok->op = '!';
        // "compl" might be ~
        else if (isAlternativeUnaryOp(tok, COMPL))
            tok->op = '~';

        if (tok->op == '!' && tok->next && tok->next->number) {
            tok->setstr(tok->next->str() == "0" ? "1" : "0");
            deleteToken(tok->next);
        } else if (tok->op == '~' && tok->next && tok->next->number) {
            tok->setstr(toString(~stringToLL(tok->next->str())));
            deleteToken(tok->next);
        } else {
            if (tok->previous && (tok->previous->number || tok->previous->name))
                continue;
            if (!tok->next || !tok->next->number)
                continue;
            switch (tok->op) {
            case '+':
                tok->setstr(tok->next->str());
                deleteToken(tok->next);
                break;
            case '-':
                tok->setstr(tok->op + tok->next->str());
                deleteToken(tok->next);
                break;
            }
        }
    }
}

void simplecpp::TokenList::constFoldMulDivRem(Token *tok)
{
    for (; tok && tok->op != ')'; tok = tok->next) {
        if (!tok->previous || !tok->previous->number)
            continue;
        if (!tok->next || !tok->next->number)
            continue;

        long long result;
        if (tok->op == '*')
            result = (stringToLL(tok->previous->str()) * stringToLL(tok->next->str()));
        else if (tok->op == '/' || tok->op == '%') {
            const long long rhs = stringToLL(tok->next->str());
            if (rhs == 0)
                throw std::overflow_error("division/modulo by zero");
            const long long lhs = stringToLL(tok->previous->str());
            if (rhs == -1 && lhs == std::numeric_limits<long long>::min())
                throw std::overflow_error("division overflow");
            if (tok->op == '/')
                result = (lhs / rhs);
            else
                result = (lhs % rhs);
        } else
            continue;

        tok = tok->previous;
        tok->setstr(toString(result));
        deleteToken(tok->next);
        deleteToken(tok->next);
    }
}

void simplecpp::TokenList::constFoldAddSub(Token *tok)
{
    for (; tok && tok->op != ')'; tok = tok->next) {
        if (!tok->previous || !tok->previous->number)
            continue;
        if (!tok->next || !tok->next->number)
            continue;

        long long result;
        if (tok->op == '+')
            result = stringToLL(tok->previous->str()) + stringToLL(tok->next->str());
        else if (tok->op == '-')
            result = stringToLL(tok->previous->str()) - stringToLL(tok->next->str());
        else
            continue;

        tok = tok->previous;
        tok->setstr(toString(result));
        deleteToken(tok->next);
        deleteToken(tok->next);
    }
}

void simplecpp::TokenList::constFoldShift(Token *tok)
{
    for (; tok && tok->op != ')'; tok = tok->next) {
        if (!tok->previous || !tok->previous->number)
            continue;
        if (!tok->next || !tok->next->number)
            continue;

        long long result;
        if (tok->str() == "<<")
            result = stringToLL(tok->previous->str()) << stringToLL(tok->next->str());
        else if (tok->str() == ">>")
            result = stringToLL(tok->previous->str()) >> stringToLL(tok->next->str());
        else
            continue;

        tok = tok->previous;
        tok->setstr(toString(result));
        deleteToken(tok->next);
        deleteToken(tok->next);
    }
}

static const std::string NOTEQ("not_eq");
void simplecpp::TokenList::constFoldComparison(Token *tok)
{
    for (; tok && tok->op != ')'; tok = tok->next) {
        if (isAlternativeBinaryOp(tok,NOTEQ))
            tok->setstr("!=");

        if (!tok->startsWithOneOf("<>=!"))
            continue;
        if (!tok->previous || !tok->previous->number)
            continue;
        if (!tok->next || !tok->next->number)
            continue;

        int result;
        if (tok->str() == "==")
            result = (stringToLL(tok->previous->str()) == stringToLL(tok->next->str()));
        else if (tok->str() == "!=")
            result = (stringToLL(tok->previous->str()) != stringToLL(tok->next->str()));
        else if (tok->str() == ">")
            result = (stringToLL(tok->previous->str()) > stringToLL(tok->next->str()));
        else if (tok->str() == ">=")
            result = (stringToLL(tok->previous->str()) >= stringToLL(tok->next->str()));
        else if (tok->str() == "<")
            result = (stringToLL(tok->previous->str()) < stringToLL(tok->next->str()));
        else if (tok->str() == "<=")
            result = (stringToLL(tok->previous->str()) <= stringToLL(tok->next->str()));
        else
            continue;

        tok = tok->previous;
        tok->setstr(toString(result));
        deleteToken(tok->next);
        deleteToken(tok->next);
    }
}

static const std::string BITAND("bitand");
static const std::string BITOR("bitor");
static const std::string XOR("xor");
void simplecpp::TokenList::constFoldBitwise(Token *tok)
{
    Token * const tok1 = tok;
    for (const char *op = "&^|"; *op; op++) {
        const std::string* alternativeOp;
        if (*op == '&')
            alternativeOp = &BITAND;
        else if (*op == '|')
            alternativeOp = &BITOR;
        else
            alternativeOp = &XOR;
        for (tok = tok1; tok && tok->op != ')'; tok = tok->next) {
            if (tok->op != *op && !isAlternativeBinaryOp(tok, *alternativeOp))
                continue;
            if (!tok->previous || !tok->previous->number)
                continue;
            if (!tok->next || !tok->next->number)
                continue;
            long long result;
            if (*op == '&')
                result = (stringToLL(tok->previous->str()) & stringToLL(tok->next->str()));
            else if (*op == '^')
                result = (stringToLL(tok->previous->str()) ^ stringToLL(tok->next->str()));
            else /*if (*op == '|')*/
                result = (stringToLL(tok->previous->str()) | stringToLL(tok->next->str()));
            tok = tok->previous;
            tok->setstr(toString(result));
            deleteToken(tok->next);
            deleteToken(tok->next);
        }
    }
}

static const std::string AND("and");
static const std::string OR("or");
void simplecpp::TokenList::constFoldLogicalOp(Token *tok)
{
    for (; tok && tok->op != ')'; tok = tok->next) {
        if (tok->name) {
            if (isAlternativeBinaryOp(tok,AND))
                tok->setstr("&&");
            else if (isAlternativeBinaryOp(tok,OR))
                tok->setstr("||");
        }
        if (tok->str() != "&&" && tok->str() != "||")
            continue;
        if (!tok->previous || !tok->previous->number)
            continue;
        if (!tok->next || !tok->next->number)
            continue;

        int result;
        if (tok->str() == "||")
            result = (stringToLL(tok->previous->str()) || stringToLL(tok->next->str()));
        else /*if (tok->str() == "&&")*/
            result = (stringToLL(tok->previous->str()) && stringToLL(tok->next->str()));

        tok = tok->previous;
        tok->setstr(toString(result));
        deleteToken(tok->next);
        deleteToken(tok->next);
    }
}

void simplecpp::TokenList::constFoldQuestionOp(Token **tok1)
{
    bool gotoTok1 = false;
    for (Token *tok = *tok1; tok && tok->op != ')'; tok =  gotoTok1 ? *tok1 : tok->next) {
        gotoTok1 = false;
        if (tok->str() != "?")
            continue;
        if (!tok->previous || !tok->next || !tok->next->next)
            throw std::runtime_error("invalid expression");
        if (!tok->previous->number)
            continue;
        if (tok->next->next->op != ':')
            continue;
        Token * const condTok = tok->previous;
        Token * const trueTok = tok->next;
        Token * const falseTok = trueTok->next->next;
        if (!falseTok)
            throw std::runtime_error("invalid expression");
        if (condTok == *tok1)
            *tok1 = (condTok->str() != "0" ? trueTok : falseTok);
        deleteToken(condTok->next); // ?
        deleteToken(trueTok->next); // :
        deleteToken(condTok->str() == "0" ? trueTok : falseTok);
        deleteToken(condTok);
        gotoTok1 = true;
    }
}

void simplecpp::TokenList::removeComments()
{
    Token *tok = frontToken;
    while (tok) {
        Token * const tok1 = tok;
        tok = tok->next;
        if (tok1->comment)
            deleteToken(tok1);
    }
}

std::string simplecpp::TokenList::readUntil(Stream &stream, const Location &location, const char start, const char end, OutputList *outputList)
{
    std::string ret;
    ret += start;

    bool backslash = false;
    char ch = 0;
    while (ch != end && ch != '\r' && ch != '\n' && stream.good()) {
        ch = stream.readChar();
        if (backslash && ch == '\n') {
            ch = 0;
            backslash = false;
            continue;
        }
        backslash = false;
        ret += ch;
        if (ch == '\\') {
            bool update_ch = false;
            char next = 0;
            do {
                next = stream.readChar();
                if (next == '\r' || next == '\n') {
                    ret.erase(ret.size()-1U);
                    backslash = (next == '\r');
                    update_ch = false;
                } else if (next == '\\')
                    update_ch = !update_ch;
                ret += next;
            } while (next == '\\');
            if (update_ch)
                ch = next;
        }
    }

    if (!stream.good() || ch != end) {
        clear();
        if (outputList) {
            Output err(files);
            err.type = Output::SYNTAX_ERROR;
            err.location = location;
            err.msg = std::string("No pair for character (") + start + "). Can't process file. File is either invalid or unicode, which is currently not supported.";
            outputList->push_back(err);
        }
        return "";
    }

    return ret;
}

std::string simplecpp::TokenList::lastLine(int maxsize) const
{
    std::string ret;
    int count = 0;
    for (const Token *tok = cback(); ; tok = tok->previous) {
        if (!sameline(tok, cback())) {
            break;
        }
        if (tok->comment)
            continue;
        if (++count > maxsize)
            return "";
        if (!ret.empty())
            ret += ' ';
        // add tokens in reverse for performance reasons
        if (tok->str()[0] == '\"')
            ret += "%rts%"; // %str%
        else if (tok->number)
            ret += "%mun%"; // %num%
        else {
            ret += tok->str();
            std::reverse(ret.end() - tok->str().length(), ret.end());
        }
    }
    std::reverse(ret.begin(), ret.end());
    return ret;
}

bool simplecpp::TokenList::isLastLinePreprocessor(int maxsize) const
{
    const Token* prevTok = nullptr;
    int count = 0;
    for (const Token *tok = cback(); ; tok = tok->previous) {
        if (!sameline(tok, cback()))
            break;
        if (tok->comment)
            continue;
        if (++count > maxsize)
            return false;
        prevTok = tok;
    }
    return prevTok && prevTok->str()[0] == '#';
}

unsigned int simplecpp::TokenList::fileIndex(const std::string &filename)
{
    for (unsigned int i = 0; i < files.size(); ++i) {
        if (files[i] == filename)
            return i;
    }
    files.push_back(filename);
    return files.size() - 1U;
}


namespace simplecpp {
    class Macro;
#if __cplusplus >= 201103L
    using MacroMap = std::unordered_map<TokenString,Macro>;
#else
    typedef std::map<TokenString,Macro> MacroMap;
#endif

    class Macro {
    public:
        explicit Macro(std::vector<std::string> &f) : nameTokDef(nullptr), valueToken(nullptr), endToken(nullptr), files(f), tokenListDefine(f), variadic(false), valueDefinedInCode_(false) {}

        Macro(const Token *tok, std::vector<std::string> &f) : nameTokDef(nullptr), files(f), tokenListDefine(f), valueDefinedInCode_(true) {
            if (sameline(tok->previousSkipComments(), tok))
                throw std::runtime_error("bad macro syntax");
            if (tok->op != '#')
                throw std::runtime_error("bad macro syntax");
            const Token * const hashtok = tok;
            tok = tok->next;
            if (!tok || tok->str() != DEFINE)
                throw std::runtime_error("bad macro syntax");
            tok = tok->next;
            if (!tok || !tok->name || !sameline(hashtok,tok))
                throw std::runtime_error("bad macro syntax");
            if (!parseDefine(tok))
                throw std::runtime_error("bad macro syntax");
        }

        Macro(const std::string &name, const std::string &value, std::vector<std::string> &f) : nameTokDef(nullptr), files(f), tokenListDefine(f), valueDefinedInCode_(false) {
            const std::string def(name + ' ' + value);
            std::istringstream istr(def);
            StdIStream stream(istr);
            tokenListDefine.readfile(stream);
            if (!parseDefine(tokenListDefine.cfront()))
                throw std::runtime_error("bad macro syntax. macroname=" + name + " value=" + value);
        }

        Macro(const Macro &other) : nameTokDef(nullptr), files(other.files), tokenListDefine(other.files), valueDefinedInCode_(other.valueDefinedInCode_) {
            *this = other;
        }

        Macro &operator=(const Macro &other) {
            if (this != &other) {
                files = other.files;
                valueDefinedInCode_ = other.valueDefinedInCode_;
                if (other.tokenListDefine.empty())
                    parseDefine(other.nameTokDef);
                else {
                    tokenListDefine = other.tokenListDefine;
                    parseDefine(tokenListDefine.cfront());
                }
                usageList = other.usageList;
            }
            return *this;
        }

        bool valueDefinedInCode() const {
            return valueDefinedInCode_;
        }

        /**
         * Expand macro. This will recursively expand inner macros.
         * @param output     destination tokenlist
         * @param rawtok     macro token
         * @param macros     list of macros
         * @param inputFiles the input files
         * @return token after macro
         * @throw Can throw wrongNumberOfParameters or invalidHashHash
         */
        const Token * expand(TokenList * const output,
                             const Token * rawtok,
                             const MacroMap &macros,
                             std::vector<std::string> &inputFiles) const {
            std::set<TokenString> expandedmacros;

            TokenList output2(inputFiles);

            if (functionLike() && rawtok->next && rawtok->next->op == '(') {
                // Copy macro call to a new tokenlist with no linebreaks
                const Token * const rawtok1 = rawtok;
                TokenList rawtokens2(inputFiles);
                rawtokens2.push_back(new Token(rawtok->str(), rawtok1->location));
                rawtok = rawtok->next;
                rawtokens2.push_back(new Token(rawtok->str(), rawtok1->location));
                rawtok = rawtok->next;
                int par = 1;
                while (rawtok && par > 0) {
                    if (rawtok->op == '(')
                        ++par;
                    else if (rawtok->op == ')')
                        --par;
                    else if (rawtok->op == '#' && !sameline(rawtok->previous, rawtok))
                        throw Error(rawtok->location, "it is invalid to use a preprocessor directive as macro parameter");
                    rawtokens2.push_back(new Token(rawtok->str(), rawtok1->location));
                    rawtok = rawtok->next;
                }
                bool first = true;
                if (valueToken && valueToken->str() == rawtok1->str())
                    first = false;
                if (expand(&output2, rawtok1->location, rawtokens2.cfront(), macros, expandedmacros, first))
                    rawtok = rawtok1->next;
            } else {
                rawtok = expand(&output2, rawtok->location, rawtok, macros, expandedmacros);
            }
            while (output2.cback() && rawtok) {
                unsigned int par = 0;
                Token* macro2tok = output2.back();
                while (macro2tok) {
                    if (macro2tok->op == '(') {
                        if (par==0)
                            break;
                        --par;
                    } else if (macro2tok->op == ')')
                        ++par;
                    macro2tok = macro2tok->previous;
                }
                if (macro2tok) { // macro2tok->op == '('
                    macro2tok = macro2tok->previous;
                    expandedmacros.insert(name());
                } else if (rawtok->op == '(')
                    macro2tok = output2.back();
                if (!macro2tok || !macro2tok->name)
                    break;
                if (output2.cfront() != output2.cback() && macro2tok->str() == this->name())
                    break;
                const MacroMap::const_iterator macro = macros.find(macro2tok->str());
                if (macro == macros.end() || !macro->second.functionLike())
                    break;
                TokenList rawtokens2(inputFiles);
                const Location loc(macro2tok->location);
                while (macro2tok) {
                    Token * const next = macro2tok->next;
                    rawtokens2.push_back(new Token(macro2tok->str(), loc));
                    output2.deleteToken(macro2tok);
                    macro2tok = next;
                }
                par = (rawtokens2.cfront() != rawtokens2.cback()) ? 1U : 0U;
                const Token *rawtok2 = rawtok;
                for (; rawtok2; rawtok2 = rawtok2->next) {
                    rawtokens2.push_back(new Token(rawtok2->str(), loc));
                    if (rawtok2->op == '(')
                        ++par;
                    else if (rawtok2->op == ')') {
                        if (par <= 1U)
                            break;
                        --par;
                    }
                }
                if (!rawtok2 || par != 1U)
                    break;
                if (macro->second.expand(&output2, rawtok->location, rawtokens2.cfront(), macros, expandedmacros) != nullptr)
                    break;
                rawtok = rawtok2->next;
            }
            output->takeTokens(output2);
            return rawtok;
        }

        /** macro name */
        const TokenString &name() const {
            return nameTokDef->str();
        }

        /** location for macro definition */
        const Location &defineLocation() const {
            return nameTokDef->location;
        }

        /** how has this macro been used so far */
        const std::list<Location> &usage() const {
            return usageList;
        }

        /** is this a function like macro */
        bool functionLike() const {
            return nameTokDef->next &&
                   nameTokDef->next->op == '(' &&
                   sameline(nameTokDef, nameTokDef->next) &&
                   nameTokDef->next->location.col == nameTokDef->location.col + nameTokDef->str().size();
        }

        /** base class for errors */
        struct Error {
            Error(const Location &loc, const std::string &s) : location(loc), what(s) {}
            const Location location;
            const std::string what;
        };

        /** Struct that is thrown when macro is expanded with wrong number of parameters */
        struct wrongNumberOfParameters : public Error {
            wrongNumberOfParameters(const Location &loc, const std::string &macroName) : Error(loc, "Wrong number of parameters for macro \'" + macroName + "\'.") {}
        };

        /** Struct that is thrown when there is invalid ## usage */
        struct invalidHashHash : public Error {
            static inline std::string format(const std::string &macroName, const std::string &message) {
                return "Invalid ## usage when expanding \'" + macroName + "\': " + message;
            }

            invalidHashHash(const Location &loc, const std::string &macroName, const std::string &message)
                : Error(loc, format(macroName, message)) { }

            static inline invalidHashHash unexpectedToken(const Location &loc, const std::string &macroName, const Token *tokenA) {
                return invalidHashHash(loc, macroName, "Unexpected token '"+ tokenA->str()+"'");
            }

            static inline invalidHashHash cannotCombine(const Location &loc, const std::string &macroName, const Token *tokenA, const Token *tokenB) {
                return invalidHashHash(loc, macroName, "Combining '"+ tokenA->str()+ "' and '"+ tokenB->str() + "' yields an invalid token.");
            }

            static inline invalidHashHash unexpectedNewline(const Location &loc, const std::string &macroName) {
                return invalidHashHash(loc, macroName, "Unexpected newline");
            }

            static inline invalidHashHash universalCharacterUB(const Location &loc, const std::string &macroName, const Token* tokenA, const std::string& strAB) {
                return invalidHashHash(loc, macroName, "Combining '\\"+ tokenA->str()+ "' and '"+ strAB.substr(tokenA->str().size()) + "' yields universal character '\\" + strAB + "'. This is undefined behavior according to C standard chapter 5.1.1.2, paragraph 4.");
            }
        };
    private:
        /** Create new token where Token::macro is set for replaced tokens */
        Token *newMacroToken(const TokenString &str, const Location &loc, bool replaced, const Token *expandedFromToken=nullptr) const {
            Token *tok = new Token(str,loc);
            if (replaced)
                tok->macro = nameTokDef->str();
            if (expandedFromToken)
                tok->setExpandedFrom(expandedFromToken, this);
            return tok;
        }

        bool parseDefine(const Token *nametoken) {
            nameTokDef = nametoken;
            variadic = false;
            if (!nameTokDef) {
                valueToken = endToken = nullptr;
                args.clear();
                return false;
            }

            // function like macro..
            if (functionLike()) {
                args.clear();
                const Token *argtok = nameTokDef->next->next;
                while (sameline(nametoken, argtok) && argtok->op != ')') {
                    if (argtok->str() == "..." &&
                        argtok->next && argtok->next->op == ')') {
                        variadic = true;
                        if (!argtok->previous->name)
                            args.push_back("__VA_ARGS__");
                        argtok = argtok->next; // goto ')'
                        break;
                    }
                    if (argtok->op != ',')
                        args.push_back(argtok->str());
                    argtok = argtok->next;
                }
                if (!sameline(nametoken, argtok)) {
                    endToken = argtok ? argtok->previous : argtok;
                    valueToken = nullptr;
                    return false;
                }
                valueToken = argtok ? argtok->next : nullptr;
            } else {
                args.clear();
                valueToken = nameTokDef->next;
            }

            if (!sameline(valueToken, nameTokDef))
                valueToken = nullptr;
            endToken = valueToken;
            while (sameline(endToken, nameTokDef))
                endToken = endToken->next;
            return true;
        }

        unsigned int getArgNum(const TokenString &str) const {
            unsigned int par = 0;
            while (par < args.size()) {
                if (str == args[par])
                    return par;
                par++;
            }
            return ~0U;
        }

        std::vector<const Token *> getMacroParameters(const Token *nameTokInst, bool calledInDefine) const {
            if (!nameTokInst->next || nameTokInst->next->op != '(' || !functionLike())
                return std::vector<const Token *>();

            std::vector<const Token *> parametertokens;
            parametertokens.push_back(nameTokInst->next);
            unsigned int par = 0U;
            for (const Token *tok = nameTokInst->next->next; calledInDefine ? sameline(tok, nameTokInst) : (tok != nullptr); tok = tok->next) {
                if (tok->op == '(')
                    ++par;
                else if (tok->op == ')') {
                    if (par == 0U) {
                        parametertokens.push_back(tok);
                        break;
                    }
                    --par;
                } else if (par == 0U && tok->op == ',' && (!variadic || parametertokens.size() < args.size()))
                    parametertokens.push_back(tok);
            }
            return parametertokens;
        }

        const Token *appendTokens(TokenList *tokens,
                                  const Location &rawloc,
                                  const Token * const lpar,
                                  const MacroMap &macros,
                                  const std::set<TokenString> &expandedmacros,
                                  const std::vector<const Token*> &parametertokens) const {
            if (!lpar || lpar->op != '(')
                return nullptr;
            unsigned int par = 0;
            const Token *tok = lpar;
            while (sameline(lpar, tok)) {
                if (tok->op == '#' && sameline(tok,tok->next) && tok->next->op == '#' && sameline(tok,tok->next->next)) {
                    // A##B => AB
                    tok = expandHashHash(tokens, rawloc, tok, macros, expandedmacros, parametertokens);
                } else if (tok->op == '#' && sameline(tok, tok->next) && tok->next->op != '#') {
                    tok = expandHash(tokens, rawloc, tok, macros, expandedmacros, parametertokens);
                } else {
                    if (!expandArg(tokens, tok, rawloc, macros, expandedmacros, parametertokens)) {
                        bool expanded = false;
                        const MacroMap::const_iterator it = macros.find(tok->str());
                        if (it != macros.end() && expandedmacros.find(tok->str()) == expandedmacros.end()) {
                            const Macro &m = it->second;
                            if (!m.functionLike()) {
                                m.expand(tokens, rawloc, tok, macros, expandedmacros);
                                expanded = true;
                            }
                        }
                        if (!expanded) {
                            tokens->push_back(new Token(*tok));
                            if (tok->macro.empty() && (par > 0 || tok->str() != "("))
                                tokens->back()->macro = name();
                        }
                    }

                    if (tok->op == '(')
                        ++par;
                    else if (tok->op == ')') {
                        --par;
                        if (par == 0U)
                            break;
                    }
                    tok = tok->next;
                }
            }
            for (Token *tok2 = tokens->front(); tok2; tok2 = tok2->next)
                tok2->location = lpar->location;
            return sameline(lpar,tok) ? tok : nullptr;
        }

        const Token * expand(TokenList * const output, const Location &loc, const Token * const nameTokInst, const MacroMap &macros, std::set<TokenString> expandedmacros, bool first=false) const {

            if (!first)
                expandedmacros.insert(nameTokInst->str());

            usageList.push_back(loc);

            if (nameTokInst->str() == "__FILE__") {
                output->push_back(new Token('\"'+loc.file()+'\"', loc));
                return nameTokInst->next;
            }
            if (nameTokInst->str() == "__LINE__") {
                output->push_back(new Token(toString(loc.line), loc));
                return nameTokInst->next;
            }
            if (nameTokInst->str() == "__COUNTER__") {
                output->push_back(new Token(toString(usageList.size()-1U), loc));
                return nameTokInst->next;
            }

            const bool calledInDefine = (loc.fileIndex != nameTokInst->location.fileIndex ||
                                         loc.line < nameTokInst->location.line);

            std::vector<const Token*> parametertokens1(getMacroParameters(nameTokInst, calledInDefine));

            if (functionLike()) {
                // No arguments => not macro expansion
                if (nameTokInst->next && nameTokInst->next->op != '(') {
                    output->push_back(new Token(nameTokInst->str(), loc));
                    return nameTokInst->next;
                }

                // Parse macro-call
                if (variadic) {
                    if (parametertokens1.size() < args.size()) {
                        throw wrongNumberOfParameters(nameTokInst->location, name());
                    }
                } else {
                    if (parametertokens1.size() != args.size() + (args.empty() ? 2U : 1U))
                        throw wrongNumberOfParameters(nameTokInst->location, name());
                }
            }

            // If macro call uses __COUNTER__ then expand that first
            TokenList tokensparams(files);
            std::vector<const Token *> parametertokens2;
            if (!parametertokens1.empty()) {
                bool counter = false;
                for (const Token *tok = parametertokens1[0]; tok != parametertokens1.back(); tok = tok->next) {
                    if (tok->str() == "__COUNTER__") {
                        counter = true;
                        break;
                    }
                }

                const MacroMap::const_iterator m = macros.find("__COUNTER__");

                if (!counter || m == macros.end())
                    parametertokens2.swap(parametertokens1);
                else {
                    const Macro &counterMacro = m->second;
                    unsigned int par = 0;
                    for (const Token *tok = parametertokens1[0]; tok && par < parametertokens1.size(); tok = tok->next) {
                        if (tok->str() == "__COUNTER__") {
                            tokensparams.push_back(new Token(toString(counterMacro.usageList.size()), tok->location));
                            counterMacro.usageList.push_back(tok->location);
                        } else {
                            tokensparams.push_back(new Token(*tok));
                            if (tok == parametertokens1[par]) {
                                parametertokens2.push_back(tokensparams.cback());
                                par++;
                            }
                        }
                    }
                }
            }

            Token * const output_end_1 = output->back();

            // expand
            for (const Token *tok = valueToken; tok != endToken;) {
                if (tok->op != '#') {
                    // A##B => AB
                    if (sameline(tok, tok->next) && tok->next && tok->next->op == '#' && tok->next->next && tok->next->next->op == '#') {
                        if (!sameline(tok, tok->next->next->next))
                            throw invalidHashHash::unexpectedNewline(tok->location, name());
                        TokenList new_output(files);
                        if (!expandArg(&new_output, tok, parametertokens2))
                            output->push_back(newMacroToken(tok->str(), loc, isReplaced(expandedmacros), tok));
                        else if (new_output.empty()) // placemarker token
                            output->push_back(newMacroToken("", loc, isReplaced(expandedmacros)));
                        else
                            for (const Token *tok2 = new_output.cfront(); tok2; tok2 = tok2->next)
                                output->push_back(newMacroToken(tok2->str(), loc, isReplaced(expandedmacros), tok2));
                        tok = tok->next;
                    } else {
                        tok = expandToken(output, loc, tok, macros, expandedmacros, parametertokens2);
                    }
                    continue;
                }

                int numberOfHash = 1;
                const Token *hashToken = tok->next;
                while (sameline(tok,hashToken) && hashToken->op == '#') {
                    hashToken = hashToken->next;
                    ++numberOfHash;
                }
                if (numberOfHash == 4 && tok->next->location.col + 1 == tok->next->next->location.col) {
                    // # ## #  => ##
                    output->push_back(newMacroToken("##", loc, isReplaced(expandedmacros)));
                    tok = hashToken;
                    continue;
                }

                if (numberOfHash >= 2 && tok->location.col + 1 < tok->next->location.col) {
                    output->push_back(new Token(*tok));
                    tok = tok->next;
                    continue;
                }

                tok = tok->next;
                if (tok == endToken) {
                    output->push_back(new Token(*tok->previous));
                    break;
                }
                if (tok->op == '#') {
                    // A##B => AB
                    tok = expandHashHash(output, loc, tok->previous, macros, expandedmacros, parametertokens2);
                } else {
                    // #123 => "123"
                    tok = expandHash(output, loc, tok->previous, macros, expandedmacros, parametertokens2);
                }
            }

            if (!functionLike()) {
                for (Token *tok = output_end_1 ? output_end_1->next : output->front(); tok; tok = tok->next) {
                    tok->macro = nameTokInst->str();
                }
            }

            if (!parametertokens1.empty())
                parametertokens1.swap(parametertokens2);

            return functionLike() ? parametertokens2.back()->next : nameTokInst->next;
        }

        const Token *recursiveExpandToken(TokenList *output, TokenList &temp, const Location &loc, const Token *tok, const MacroMap &macros, const std::set<TokenString> &expandedmacros, const std::vector<const Token*> &parametertokens) const {
            if (!(temp.cback() && temp.cback()->name && tok->next && tok->next->op == '(')) {
                output->takeTokens(temp);
                return tok->next;
            }

            if (!sameline(tok, tok->next)) {
                output->takeTokens(temp);
                return tok->next;
            }

            const MacroMap::const_iterator it = macros.find(temp.cback()->str());
            if (it == macros.end() || expandedmacros.find(temp.cback()->str()) != expandedmacros.end()) {
                output->takeTokens(temp);
                return tok->next;
            }

            const Macro &calledMacro = it->second;
            if (!calledMacro.functionLike()) {
                output->takeTokens(temp);
                return tok->next;
            }

            TokenList temp2(files);
            temp2.push_back(new Token(temp.cback()->str(), tok->location));

            const Token * const tok2 = appendTokens(&temp2, loc, tok->next, macros, expandedmacros, parametertokens);
            if (!tok2)
                return tok->next;
            output->takeTokens(temp);
            output->deleteToken(output->back());
            calledMacro.expand(output, loc, temp2.cfront(), macros, expandedmacros);
            return tok2->next;
        }

        const Token *expandToken(TokenList *output, const Location &loc, const Token *tok, const MacroMap &macros, const std::set<TokenString> &expandedmacros, const std::vector<const Token*> &parametertokens) const {
            // Not name..
            if (!tok->name) {
                output->push_back(newMacroToken(tok->str(), loc, true, tok));
                return tok->next;
            }

            // Macro parameter..
            {
                TokenList temp(files);
                if (expandArg(&temp, tok, loc, macros, expandedmacros, parametertokens)) {
                    if (tok->str() == "__VA_ARGS__" && temp.empty() && output->cback() && output->cback()->str() == "," &&
                        tok->nextSkipComments() && tok->nextSkipComments()->str() == ")")
                        output->deleteToken(output->back());
                    return recursiveExpandToken(output, temp, loc, tok, macros, expandedmacros, parametertokens);
                }
            }

            // Macro..
            const MacroMap::const_iterator it = macros.find(tok->str());
            if (it != macros.end() && expandedmacros.find(tok->str()) == expandedmacros.end()) {
                std::set<std::string> expandedmacros2(expandedmacros);
                expandedmacros2.insert(tok->str());

                const Macro &calledMacro = it->second;
                if (!calledMacro.functionLike()) {
                    TokenList temp(files);
                    calledMacro.expand(&temp, loc, tok, macros, expandedmacros);
                    return recursiveExpandToken(output, temp, loc, tok, macros, expandedmacros2, parametertokens);
                }
                if (!sameline(tok, tok->next) || tok->next->op != '(') {
                    output->push_back(newMacroToken(tok->str(), loc, true, tok));
                    return tok->next;
                }
                TokenList tokens(files);
                tokens.push_back(new Token(*tok));
                const Token * const tok2 = appendTokens(&tokens, loc, tok->next, macros, expandedmacros, parametertokens);
                if (!tok2) {
                    output->push_back(newMacroToken(tok->str(), loc, true, tok));
                    return tok->next;
                }
                TokenList temp(files);
                calledMacro.expand(&temp, loc, tokens.cfront(), macros, expandedmacros);
                return recursiveExpandToken(output, temp, loc, tok2, macros, expandedmacros2, parametertokens);
            }

            if (tok->str() == DEFINED) {
                const Token * const tok2 = tok->next;
                const Token * const tok3 = tok2 ? tok2->next : nullptr;
                const Token * const tok4 = tok3 ? tok3->next : nullptr;
                const Token *defToken = nullptr;
                const Token *lastToken = nullptr;
                if (sameline(tok, tok4) && tok2->op == '(' && tok3->name && tok4->op == ')') {
                    defToken = tok3;
                    lastToken = tok4;
                } else if (sameline(tok,tok2) && tok2->name) {
                    defToken = lastToken = tok2;
                }
                if (defToken) {
                    std::string macroName = defToken->str();
                    if (defToken->next && defToken->next->op == '#' && defToken->next->next && defToken->next->next->op == '#' && defToken->next->next->next && defToken->next->next->next->name && sameline(defToken,defToken->next->next->next)) {
                        TokenList temp(files);
                        if (expandArg(&temp, defToken, parametertokens))
                            macroName = temp.cback()->str();
                        if (expandArg(&temp, defToken->next->next->next, parametertokens))
                            macroName += temp.cback()->str();
                        else
                            macroName += defToken->next->next->next->str();
                        lastToken = defToken->next->next->next;
                    }
                    const bool def = (macros.find(macroName) != macros.end());
                    output->push_back(newMacroToken(def ? "1" : "0", loc, true));
                    return lastToken->next;
                }
            }

            output->push_back(newMacroToken(tok->str(), loc, true, tok));
            return tok->next;
        }

        bool expandArg(TokenList *output, const Token *tok, const std::vector<const Token*> &parametertokens) const {
            if (!tok->name)
                return false;

            const unsigned int argnr = getArgNum(tok->str());
            if (argnr >= args.size())
                return false;

            // empty variadic parameter
            if (variadic && argnr + 1U >= parametertokens.size())
                return true;

            for (const Token *partok = parametertokens[argnr]->next; partok != parametertokens[argnr + 1U]; partok = partok->next)
                output->push_back(new Token(*partok));

            return true;
        }

        bool expandArg(TokenList *output, const Token *tok, const Location &loc, const MacroMap &macros, const std::set<TokenString> &expandedmacros, const std::vector<const Token*> &parametertokens) const {
            if (!tok->name)
                return false;
            const unsigned int argnr = getArgNum(tok->str());
            if (argnr >= args.size())
                return false;
            if (variadic && argnr + 1U >= parametertokens.size()) // empty variadic parameter
                return true;
            for (const Token *partok = parametertokens[argnr]->next; partok != parametertokens[argnr + 1U];) {
                const MacroMap::const_iterator it = macros.find(partok->str());
                if (it != macros.end() && !partok->isExpandedFrom(&it->second) && (partok->str() == name() || expandedmacros.find(partok->str()) == expandedmacros.end()))
                    partok = it->second.expand(output, loc, partok, macros, expandedmacros);
                else {
                    output->push_back(newMacroToken(partok->str(), loc, isReplaced(expandedmacros), partok));
                    output->back()->macro = partok->macro;
                    partok = partok->next;
                }
            }
            return true;
        }

        /**
         * Expand #X => "X"
         * @param output  destination tokenlist
         * @param loc     location for expanded token
         * @param tok     The # token
         * @param macros  all macros
         * @param expandedmacros   set with expanded macros, with this macro
         * @param parametertokens  parameters given when expanding this macro
         * @return token after the X
         */
        const Token *expandHash(TokenList *output, const Location &loc, const Token *tok, const MacroMap &macros, const std::set<TokenString> &expandedmacros, const std::vector<const Token*> &parametertokens) const {
            TokenList tokenListHash(files);
            tok = expandToken(&tokenListHash, loc, tok->next, macros, expandedmacros, parametertokens);
            std::ostringstream ostr;
            ostr << '\"';
            for (const Token *hashtok = tokenListHash.cfront(); hashtok; hashtok = hashtok->next)
                ostr << hashtok->str();
            ostr << '\"';
            output->push_back(newMacroToken(escapeString(ostr.str()), loc, isReplaced(expandedmacros)));
            return tok;
        }

        /**
         * Expand A##B => AB
         * The A should already be expanded. Call this when you reach the first # token
         * @param output  destination tokenlist
         * @param loc     location for expanded token
         * @param tok     first # token
         * @param macros  all macros
         * @param expandedmacros   set with expanded macros, with this macro
         * @param parametertokens  parameters given when expanding this macro
         * @return token after B
         */
        const Token *expandHashHash(TokenList *output, const Location &loc, const Token *tok, const MacroMap &macros, const std::set<TokenString> &expandedmacros, const std::vector<const Token*> &parametertokens) const {
            Token *A = output->back();
            if (!A)
                throw invalidHashHash(tok->location, name(), "Missing first argument");
            if (!sameline(tok, tok->next) || !sameline(tok, tok->next->next))
                throw invalidHashHash::unexpectedNewline(tok->location, name());

            const bool canBeConcatenatedWithEqual = A->isOneOf("+-*/%&|^") || A->str() == "<<" || A->str() == ">>";
            const bool canBeConcatenatedStringOrChar = isStringLiteral_(A->str()) || isCharLiteral_(A->str());
            if (!A->name && !A->number && A->op != ',' && !A->str().empty() && !canBeConcatenatedWithEqual && !canBeConcatenatedStringOrChar)
                throw invalidHashHash::unexpectedToken(tok->location, name(), A);

            Token * const B = tok->next->next;
            if (!B->name && !B->number && B->op && !B->isOneOf("#="))
                throw invalidHashHash::unexpectedToken(tok->location, name(), B);

            if ((canBeConcatenatedWithEqual && B->op != '=') ||
                (!canBeConcatenatedWithEqual && B->op == '='))
                throw invalidHashHash::cannotCombine(tok->location, name(), A, B);

            // Superficial check; more in-depth would in theory be possible _after_ expandArg
            if (canBeConcatenatedStringOrChar && (B->number || !B->name))
                throw invalidHashHash::cannotCombine(tok->location, name(), A, B);

            TokenList tokensB(files);
            const Token *nextTok = B->next;

            if (canBeConcatenatedStringOrChar) {
                // It seems clearer to handle this case separately even though the code is similar-ish, but we don't want to merge here.
                // TODO The question is whether the ## or varargs may still apply, and how to provoke?
                if (expandArg(&tokensB, B, parametertokens)) {
                    for (Token *b = tokensB.front(); b; b = b->next)
                        b->location = loc;
                } else {
                    tokensB.push_back(new Token(*B));
                    tokensB.back()->location = loc;
                }
                output->takeTokens(tokensB);
            } else {
                std::string strAB;

                const bool varargs = variadic && !args.empty() && B->str() == args[args.size()-1U];

                if (expandArg(&tokensB, B, parametertokens)) {
                    if (tokensB.empty())
                        strAB = A->str();
                    else if (varargs && A->op == ',') {
                        strAB = ",";
                    } else {
                        strAB = A->str() + tokensB.cfront()->str();
                        tokensB.deleteToken(tokensB.front());
                    }
                } else {
                    strAB = A->str() + B->str();
                }

                // producing universal character is undefined behavior
                if (A->previous && A->previous->str() == "\\") {
                    if (strAB[0] == 'u' && strAB.size() == 5)
                        throw invalidHashHash::universalCharacterUB(tok->location, name(), A, strAB);
                    if (strAB[0] == 'U' && strAB.size() == 9)
                        throw invalidHashHash::universalCharacterUB(tok->location, name(), A, strAB);
                }

                if (varargs && tokensB.empty() && tok->previous->str() == ",")
                    output->deleteToken(A);
                else if (strAB != "," && macros.find(strAB) == macros.end()) {
                    A->setstr(strAB);
                    for (Token *b = tokensB.front(); b; b = b->next)
                        b->location = loc;
                    output->takeTokens(tokensB);
                } else if (sameline(B, nextTok) && sameline(B, nextTok->next) && nextTok->op == '#' && nextTok->next->op == '#') {
                    TokenList output2(files);
                    output2.push_back(new Token(strAB, tok->location));
                    nextTok = expandHashHash(&output2, loc, nextTok, macros, expandedmacros, parametertokens);
                    output->deleteToken(A);
                    output->takeTokens(output2);
                } else {
                    output->deleteToken(A);
                    TokenList tokens(files);
                    tokens.push_back(new Token(strAB, tok->location));
                    // for function like macros, push the (...)
                    if (tokensB.empty() && sameline(B,B->next) && B->next->op=='(') {
                        const MacroMap::const_iterator it = macros.find(strAB);
                        if (it != macros.end() && expandedmacros.find(strAB) == expandedmacros.end() && it->second.functionLike()) {
                            const Token * const tok2 = appendTokens(&tokens, loc, B->next, macros, expandedmacros, parametertokens);
                            if (tok2)
                                nextTok = tok2->next;
                        }
                    }
                    expandToken(output, loc, tokens.cfront(), macros, expandedmacros, parametertokens);
                    for (Token *b = tokensB.front(); b; b = b->next)
                        b->location = loc;
                    output->takeTokens(tokensB);
                }
            }

            return nextTok;
        }

        static bool isReplaced(const std::set<std::string> &expandedmacros) {
            // return true if size > 1
            std::set<std::string>::const_iterator it = expandedmacros.begin();
            if (it == expandedmacros.end())
                return false;
            ++it;
            return (it != expandedmacros.end());
        }

        /** name token in definition */
        const Token *nameTokDef;

        /** arguments for macro */
        std::vector<TokenString> args;

        /** first token in replacement string */
        const Token *valueToken;

        /** token after replacement string */
        const Token *endToken;

        /** files */
        std::vector<std::string> &files;

        /** this is used for -D where the definition is not seen anywhere in code */
        TokenList tokenListDefine;

        /** usage of this macro */
        mutable std::list<Location> usageList;

        /** is macro variadic? */
        bool variadic;

        /** was the value of this macro actually defined in the code? */
        bool valueDefinedInCode_;
    };
}

namespace simplecpp {

#ifdef __CYGWIN__
    bool startsWith(const std::string &str, const std::string &s)
    {
        return (str.size() >= s.size() && str.compare(0, s.size(), s) == 0);
    }

    std::string convertCygwinToWindowsPath(const std::string &cygwinPath)
    {
        std::string windowsPath;

        std::string::size_type pos = 0;
        if (cygwinPath.size() >= 11 && startsWith(cygwinPath, "/cygdrive/")) {
            const unsigned char driveLetter = cygwinPath[10];
            if (std::isalpha(driveLetter)) {
                if (cygwinPath.size() == 11) {
                    windowsPath = toupper(driveLetter);
                    windowsPath += ":\\";   // volume root directory
                    pos = 11;
                } else if (cygwinPath[11] == '/') {
                    windowsPath = toupper(driveLetter);
                    windowsPath += ":";
                    pos = 11;
                }
            }
        }

        for (; pos < cygwinPath.size(); ++pos) {
            unsigned char c = cygwinPath[pos];
            if (c == '/')
                c = '\\';
            windowsPath += c;
        }

        return windowsPath;
    }
#endif
}

#ifdef SIMPLECPP_WINDOWS

#if __cplusplus >= 201103L
using MyMutex = std::mutex;
template<class T>
using MyLock = std::lock_guard<T>;
#else
class MyMutex {
public:
    MyMutex() {
        InitializeCriticalSection(&m_criticalSection);
    }

    ~MyMutex() {
        DeleteCriticalSection(&m_criticalSection);
    }

    CRITICAL_SECTION* lock() {
        return &m_criticalSection;
    }
private:
    CRITICAL_SECTION m_criticalSection;
};

template<typename T>
class MyLock {
public:
    explicit MyLock(T& m)
        : m_mutex(m) {
        EnterCriticalSection(m_mutex.lock());
    }

    ~MyLock() {
        LeaveCriticalSection(m_mutex.lock());
    }

private:
    MyLock& operator=(const MyLock&);
    MyLock(const MyLock&);

    T& m_mutex;
};
#endif

class RealFileNameMap {
public:
    RealFileNameMap() {}

    bool getCacheEntry(const std::string& path, std::string& returnPath) {
        MyLock<MyMutex> lock(m_mutex);

        const std::map<std::string, std::string>::iterator it = m_fileMap.find(path);
        if (it != m_fileMap.end()) {
            returnPath = it->second;
            return true;
        }
        return false;
    }

    void addToCache(const std::string& path, const std::string& actualPath) {
        MyLock<MyMutex> lock(m_mutex);
        m_fileMap[path] = actualPath;
    }

private:
    std::map<std::string, std::string> m_fileMap;
    MyMutex m_mutex;
};

static RealFileNameMap realFileNameMap;

static bool realFileName(const std::string &f, std::string &result)
{
    // are there alpha characters in last subpath?
    bool alpha = false;
    for (std::string::size_type pos = 1; pos <= f.size(); ++pos) {
        const unsigned char c = f[f.size() - pos];
        if (c == '/' || c == '\\')
            break;
        if (std::isalpha(c)) {
            alpha = true;
            break;
        }
    }

    // do not convert this path if there are no alpha characters (either pointless or cause wrong results for . and ..)
    if (!alpha)
        return false;

    // Lookup filename or foldername on file system
    if (!realFileNameMap.getCacheEntry(f, result)) {

        WIN32_FIND_DATAA FindFileData;

#ifdef __CYGWIN__
        const std::string fConverted = simplecpp::convertCygwinToWindowsPath(f);
        const HANDLE hFind = FindFirstFileExA(fConverted.c_str(), FindExInfoBasic, &FindFileData, FindExSearchNameMatch, NULL, 0);
#else
        HANDLE hFind = FindFirstFileExA(f.c_str(), FindExInfoBasic, &FindFileData, FindExSearchNameMatch, NULL, 0);
#endif

        if (INVALID_HANDLE_VALUE == hFind)
            return false;
        result = FindFileData.cFileName;
        realFileNameMap.addToCache(f, result);
        FindClose(hFind);
    }
    return true;
}

static RealFileNameMap realFilePathMap;

/** Change case in given path to match filesystem */
static std::string realFilename(const std::string &f)
{
    std::string ret;
    ret.reserve(f.size()); // this will be the final size
    if (realFilePathMap.getCacheEntry(f, ret))
        return ret;

    // Current subpath
    std::string subpath;

    for (std::string::size_type pos = 0; pos < f.size(); ++pos) {
        const unsigned char c = f[pos];

        // Separator.. add subpath and separator
        if (c == '/' || c == '\\') {
            // if subpath is empty just add separator
            if (subpath.empty()) {
                ret += c;
                continue;
            }

            const bool isDriveSpecification =
                (pos == 2 && subpath.size() == 2 && std::isalpha(subpath[0]) && subpath[1] == ':');

            // Append real filename (proper case)
            std::string f2;
            if (!isDriveSpecification && realFileName(f.substr(0, pos), f2))
                ret += f2;
            else
                ret += subpath;

            subpath.clear();

            // Append separator
            ret += c;
        } else {
            subpath += c;
        }
    }

    if (!subpath.empty()) {
        std::string f2;
        if (realFileName(f,f2))
            ret += f2;
        else
            ret += subpath;
    }

    realFilePathMap.addToCache(f, ret);
    return ret;
}

static bool isAbsolutePath(const std::string &path)
{
    if (path.length() >= 3 && path[0] > 0 && std::isalpha(path[0]) && path[1] == ':' && (path[2] == '\\' || path[2] == '/'))
        return true;
    return path.length() > 1U && (path[0] == '/' || path[0] == '\\');
}
#else
#define realFilename(f)  f

static bool isAbsolutePath(const std::string &path)
{
    return path.length() > 1U && path[0] == '/';
}
#endif

namespace simplecpp {
    /**
     * perform path simplifications for . and ..
     */
    std::string simplifyPath(std::string path)
    {
        if (path.empty())
            return path;

        std::string::size_type pos;

        // replace backslash separators
        std::replace(path.begin(), path.end(), '\\', '/');

        const bool unc(path.compare(0,2,"//") == 0);

        // replace "//" with "/"
        pos = 0;
        while ((pos = path.find("//",pos)) != std::string::npos) {
            path.erase(pos,1);
        }

        // remove "./"
        pos = 0;
        while ((pos = path.find("./",pos)) != std::string::npos) {
            if (pos == 0 || path[pos - 1U] == '/')
                path.erase(pos,2);
            else
                pos += 2;
        }

        // remove trailing dot if path ends with "/."
        if (endsWith(path,"/."))
            path.erase(path.size()-1);

        // simplify ".."
        pos = 1; // don't simplify ".." if path starts with that
        while ((pos = path.find("/..", pos)) != std::string::npos) {
            // not end of path, then string must be "/../"
            if (pos + 3 < path.size() && path[pos + 3] != '/') {
                ++pos;
                continue;
            }
            // get previous subpath
            std::string::size_type pos1 = path.rfind('/', pos - 1U);
            if (pos1 == std::string::npos) {
                pos1 = 0;
            } else {
                pos1 += 1U;
            }
            const std::string previousSubPath = path.substr(pos1, pos - pos1);
            if (previousSubPath == "..") {
                // don't simplify
                ++pos;
            } else {
                // remove previous subpath and ".."
                path.erase(pos1, pos - pos1 + 4);
                if (path.empty())
                    path = ".";
                // update pos
                pos = (pos1 == 0) ? 1 : (pos1 - 1);
            }
        }

        // Remove trailing '/'?
        //if (path.size() > 1 && endsWith(path, "/"))
        //    path.erase(path.size()-1);

        if (unc)
            path = '/' + path;

        // cppcheck-suppress duplicateExpressionTernary - platform-dependent implementation
        return strpbrk(path.c_str(), "*?") == nullptr ? realFilename(path) : path;
    }
}

/** Evaluate sizeof(type) */
static void simplifySizeof(simplecpp::TokenList &expr, const std::map<std::string, std::size_t> &sizeOfType)
{
    for (simplecpp::Token *tok = expr.front(); tok; tok = tok->next) {
        if (tok->str() != "sizeof")
            continue;
        simplecpp::Token *tok1 = tok->next;
        if (!tok1) {
            throw std::runtime_error("missing sizeof argument");
        }
        simplecpp::Token *tok2 = tok1->next;
        if (!tok2) {
            throw std::runtime_error("missing sizeof argument");
        }
        if (tok1->op == '(') {
            tok1 = tok1->next;
            while (tok2->op != ')') {
                tok2 = tok2->next;
                if (!tok2) {
                    throw std::runtime_error("invalid sizeof expression");
                }
            }
        }

        std::string type;
        for (simplecpp::Token *typeToken = tok1; typeToken != tok2; typeToken = typeToken->next) {
            if ((typeToken->str() == "unsigned" || typeToken->str() == "signed") && typeToken->next->name)
                continue;
            if (typeToken->str() == "*" && type.find('*') != std::string::npos)
                continue;
            if (!type.empty())
                type += ' ';
            type += typeToken->str();
        }

        const std::map<std::string, std::size_t>::const_iterator it = sizeOfType.find(type);
        if (it != sizeOfType.end())
            tok->setstr(toString(it->second));
        else
            continue;

        tok2 = tok2->next;
        while (tok->next != tok2)
            expr.deleteToken(tok->next);
    }
}

/** Evaluate __has_include(file) */
static std::string openHeader(std::ifstream &f, const simplecpp::DUI &dui, const std::string &sourcefile, const std::string &header, bool systemheader);
static void simplifyHasInclude(simplecpp::TokenList &expr, const simplecpp::DUI &dui)
{
    for (simplecpp::Token *tok = expr.front(); tok; tok = tok->next) {
        if (tok->str() != "__has_include")
            continue;
        simplecpp::Token *tok1 = tok->next;
        if (!tok1) {
            throw std::runtime_error("missing __has_include argument");
        }
        simplecpp::Token *tok2 = tok1->next;
        if (!tok2) {
            throw std::runtime_error("missing __has_include argument");
        }
        if (tok1->op == '(') {
            tok1 = tok1->next;
            while (tok2->op != ')') {
                tok2 = tok2->next;
                if (!tok2) {
                    throw std::runtime_error("invalid __has_include expression");
                }
            }
        }

        const std::string &sourcefile = tok->location.file();
        const bool systemheader = (tok1 && tok1->op == '<');
        std::string header;
        if (systemheader) {
            simplecpp::Token *tok3 = tok1->next;
            if (!tok3) {
                throw std::runtime_error("missing __has_include closing angular bracket");
            }
            while (tok3->op != '>') {
                tok3 = tok3->next;
                if (!tok3) {
                    throw std::runtime_error("invalid __has_include expression");
                }
            }

            for (simplecpp::Token *headerToken = tok1->next; headerToken != tok3; headerToken = headerToken->next)
                header += headerToken->str();
            // cppcheck-suppress selfAssignment - platform-dependent implementation
            header = realFilename(header);
        }
        else {
            header = realFilename(tok1->str().substr(1U, tok1->str().size() - 2U));
        }
        std::ifstream f;
        const std::string header2 = openHeader(f,dui,sourcefile,header,systemheader);
        tok->setstr(header2.empty() ? "0" : "1");

        tok2 = tok2->next;
        while (tok->next != tok2)
            expr.deleteToken(tok->next);
    }
}

static const char * const altopData[] = {"and","or","bitand","bitor","compl","not","not_eq","xor"};
static const std::set<std::string> altop(&altopData[0], &altopData[8]);
static void simplifyName(simplecpp::TokenList &expr)
{
    for (simplecpp::Token *tok = expr.front(); tok; tok = tok->next) {
        if (tok->name) {
            if (altop.find(tok->str()) != altop.end()) {
                bool alt;
                if (tok->str() == "not" || tok->str() == "compl") {
                    alt = isAlternativeUnaryOp(tok,tok->str());
                } else {
                    alt = isAlternativeBinaryOp(tok,tok->str());
                }
                if (alt)
                    continue;
            }
            tok->setstr("0");
        }
    }
}

/*
 * Reads at least minlen and at most maxlen digits (inc. prefix) in base base
 * from s starting at position pos and converts them to a
 * unsigned long long value, updating pos to point to the first
 * unused element of s.
 * Returns ULLONG_MAX if the result is not representable and
 * throws if the above requirements were not possible to satisfy.
 */
static unsigned long long stringToULLbounded(
    const std::string& s,
    std::size_t& pos,
    int base = 0,
    std::ptrdiff_t minlen = 1,
    std::size_t maxlen = std::string::npos
)
{
    const std::string sub = s.substr(pos, maxlen);
    const char * const start = sub.c_str();
    char* end;
    const unsigned long long value = std::strtoull(start, &end, base);
    pos += end - start;
    if (end - start < minlen)
        throw std::runtime_error("expected digit");
    return value;
}

/* Converts character literal (including prefix, but not ud-suffix)
 * to long long value.
 *
 * Assumes ASCII-compatible single-byte encoded str for narrow literals
 * and UTF-8 otherwise.
 *
 * For target assumes
 * - execution character set encoding matching str
 * - UTF-32 execution wide-character set encoding
 * - requirements for __STDC_UTF_16__, __STDC_UTF_32__ and __STDC_ISO_10646__ satisfied
 * - char16_t is 16bit wide
 * - char32_t is 32bit wide
 * - wchar_t is 32bit wide and unsigned
 * - matching char signedness to host
 * - matching sizeof(int) to host
 *
 * For host assumes
 * - ASCII-compatible execution character set
 *
 * For host and target assumes
 * - CHAR_BIT == 8
 * - two's complement
 *
 * Implements multi-character narrow literals according to GCC's behavior,
 * except multi code unit universal character names are not supported.
 * Multi-character wide literals are not supported.
 * Limited support of universal character names for non-UTF-8 execution character set encodings.
 */
long long simplecpp::characterLiteralToLL(const std::string& str)
{
    // default is wide/utf32
    bool narrow = false;
    bool utf8 = false;
    bool utf16 = false;

    std::size_t pos;

    if (!str.empty() && str[0] == '\'') {
        narrow = true;
        pos = 1;
    } else if (str.size() >= 2 && str[0] == 'u' && str[1] == '\'') {
        utf16 = true;
        pos = 2;
    } else if (str.size() >= 3 && str[0] == 'u' && str[1] == '8' && str[2] == '\'') {
        utf8 = true;
        pos = 3;
    } else if (str.size() >= 2 && (str[0] == 'L' || str[0] == 'U') && str[1] == '\'') {
        pos = 2;
    } else
        throw std::runtime_error("expected a character literal");

    unsigned long long multivalue = 0;

    std::size_t nbytes = 0;

    while (pos + 1 < str.size()) {
        if (str[pos] == '\'' || str[pos] == '\n')
            throw std::runtime_error("raw single quotes and newlines not allowed in character literals");

        if (nbytes >= 1 && !narrow)
            throw std::runtime_error("multiple characters only supported in narrow character literals");

        unsigned long long value;

        if (str[pos] == '\\') {
            pos++;
            const char escape = str[pos++];

            if (pos >= str.size())
                throw std::runtime_error("unexpected end of character literal");

            switch (escape) {
            // obscure GCC extensions
            case '%':
            case '(':
            case '[':
            case '{':
            // standard escape sequences
            case '\'':
            case '"':
            case '?':
            case '\\':
                value = static_cast<unsigned char>(escape);
                break;

            case 'a':
                value = static_cast<unsigned char>('\a');
                break;
            case 'b':
                value = static_cast<unsigned char>('\b');
                break;
            case 'f':
                value = static_cast<unsigned char>('\f');
                break;
            case 'n':
                value = static_cast<unsigned char>('\n');
                break;
            case 'r':
                value = static_cast<unsigned char>('\r');
                break;
            case 't':
                value = static_cast<unsigned char>('\t');
                break;
            case 'v':
                value = static_cast<unsigned char>('\v');
                break;

            // GCC extension for ESC character
            case 'e':
            case 'E':
                value = static_cast<unsigned char>('\x1b');
                break;

            case '0':
            case '1':
            case '2':
            case '3':
            case '4':
            case '5':
            case '6':
            case '7':
                // octal escape sequences consist of 1 to 3 digits
                value = stringToULLbounded(str, --pos, 8, 1, 3);
                break;

            case 'x':
                // hexadecimal escape sequences consist of at least 1 digit
                value = stringToULLbounded(str, pos, 16);
                break;

            case 'u':
            case 'U': {
                // universal character names have exactly 4 or 8 digits
                const std::size_t ndigits = (escape == 'u' ? 4 : 8);
                value = stringToULLbounded(str, pos, 16, ndigits, ndigits);

                // UTF-8 encodes code points above 0x7f in multiple code units
                // code points above 0x10ffff are not allowed
                if (((narrow || utf8) && value > 0x7f) || (utf16 && value > 0xffff) || value > 0x10ffff)
                    throw std::runtime_error("code point too large");

                if (value >= 0xd800 && value <= 0xdfff)
                    throw std::runtime_error("surrogate code points not allowed in universal character names");

                break;
            }

            default:
                throw std::runtime_error("invalid escape sequence");
            }
        } else {
            value = static_cast<unsigned char>(str[pos++]);

            if (!narrow && value >= 0x80) {
                // Assuming this is a UTF-8 encoded code point.
                // This decoder may not completely validate the input.
                // Noncharacters are neither rejected nor replaced.

                int additional_bytes;
                if (value >= 0xf5)  // higher values would result in code points above 0x10ffff
                    throw std::runtime_error("assumed UTF-8 encoded source, but sequence is invalid");
                if (value >= 0xf0)
                    additional_bytes = 3;
                else if (value >= 0xe0)
                    additional_bytes = 2;
                else if (value >= 0xc2) // 0xc0 and 0xc1 are always overlong 2-bytes encodings
                    additional_bytes = 1;
                else
                    throw std::runtime_error("assumed UTF-8 encoded source, but sequence is invalid");

                value &= (1 << (6 - additional_bytes)) - 1;

                while (additional_bytes--) {
                    if (pos + 1 >= str.size())
                        throw std::runtime_error("assumed UTF-8 encoded source, but character literal ends unexpectedly");

                    const unsigned char c = str[pos++];

                    if (((c >> 6) != 2)    // ensure c has form 0xb10xxxxxx
                        || (!value && additional_bytes == 1 && c < 0xa0)    // overlong 3-bytes encoding
                        || (!value && additional_bytes == 2 && c < 0x90))   // overlong 4-bytes encoding
                        throw std::runtime_error("assumed UTF-8 encoded source, but sequence is invalid");

                    value = (value << 6) | (c & ((1 << 7) - 1));
                }

                if (value >= 0xd800 && value <= 0xdfff)
                    throw std::runtime_error("assumed UTF-8 encoded source, but sequence is invalid");

                if ((utf8 && value > 0x7f) || (utf16 && value > 0xffff) || value > 0x10ffff)
                    throw std::runtime_error("code point too large");
            }
        }

        if (((narrow || utf8) && value > std::numeric_limits<unsigned char>::max()) || (utf16 && value >> 16) || value >> 32)
            throw std::runtime_error("numeric escape sequence too large");

        multivalue <<= CHAR_BIT;
        multivalue |= value;
        nbytes++;
    }

    if (pos + 1 != str.size() || str[pos] != '\'')
        throw std::runtime_error("missing closing quote in character literal");

    if (!nbytes)
        throw std::runtime_error("empty character literal");

    // ordinary narrow character literal's value is determined by (possibly signed) char
    if (narrow && nbytes == 1)
        return static_cast<char>(multivalue);

    // while multi-character literal's value is determined by (signed) int
    if (narrow)
        return static_cast<int>(multivalue);

    // All other cases are unsigned. Since long long is at least 64bit wide,
    // while the literals at most 32bit wide, the conversion preserves all values.
    return multivalue;
}

static void simplifyNumbers(simplecpp::TokenList &expr)
{
    for (simplecpp::Token *tok = expr.front(); tok; tok = tok->next) {
        if (tok->str().size() == 1U)
            continue;
        if (tok->str().compare(0,2,"0x") == 0)
            tok->setstr(toString(stringToULL(tok->str())));
        else if (!tok->number && tok->str().find('\'') != std::string::npos)
            tok->setstr(toString(simplecpp::characterLiteralToLL(tok->str())));
    }
}

static void simplifyComments(simplecpp::TokenList &expr)
{
    for (simplecpp::Token *tok = expr.front(); tok;) {
        simplecpp::Token * const d = tok;
        tok = tok->next;
        if (d->comment)
            expr.deleteToken(d);
    }
}

static long long evaluate(simplecpp::TokenList &expr, const simplecpp::DUI &dui, const std::map<std::string, std::size_t> &sizeOfType)
{
    simplifyComments(expr);
    simplifySizeof(expr, sizeOfType);
    simplifyHasInclude(expr, dui);
    simplifyName(expr);
    simplifyNumbers(expr);
    expr.constFold();
    // TODO: handle invalid expressions
    return expr.cfront() && expr.cfront() == expr.cback() && expr.cfront()->number ? stringToLL(expr.cfront()->str()) : 0LL;
}

static const simplecpp::Token *gotoNextLine(const simplecpp::Token *tok)
{
    const unsigned int line = tok->location.line;
    const unsigned int file = tok->location.fileIndex;
    while (tok && tok->location.line == line && tok->location.fileIndex == file)
        tok = tok->next;
    return tok;
}

#ifdef SIMPLECPP_WINDOWS

class NonExistingFilesCache {
public:
    NonExistingFilesCache() {}

    bool contains(const std::string& path) {
        MyLock<MyMutex> lock(m_mutex);
        return (m_pathSet.find(path) != m_pathSet.end());
    }

    void add(const std::string& path) {
        MyLock<MyMutex> lock(m_mutex);
        m_pathSet.insert(path);
    }

    void clear() {
        MyLock<MyMutex> lock(m_mutex);
        m_pathSet.clear();
    }

private:
    std::set<std::string> m_pathSet;
    MyMutex m_mutex;
};

static NonExistingFilesCache nonExistingFilesCache;

#endif

static std::string openHeader(std::ifstream &f, const std::string &path)
{
    std::string simplePath = simplecpp::simplifyPath(path);
#ifdef SIMPLECPP_WINDOWS
    if (nonExistingFilesCache.contains(simplePath))
        return "";  // file is known not to exist, skip expensive file open call
#endif
    f.open(simplePath.c_str());
    if (f.is_open())
        return simplePath;
#ifdef SIMPLECPP_WINDOWS
    nonExistingFilesCache.add(simplePath);
#endif
    return "";
}

static std::string getRelativeFileName(const std::string &sourcefile, const std::string &header)
{
    if (sourcefile.find_first_of("\\/") != std::string::npos)
        return simplecpp::simplifyPath(sourcefile.substr(0, sourcefile.find_last_of("\\/") + 1U) + header);
    return simplecpp::simplifyPath(header);
}

static std::string openHeaderRelative(std::ifstream &f, const std::string &sourcefile, const std::string &header)
{
    return openHeader(f, getRelativeFileName(sourcefile, header));
}

static std::string getIncludePathFileName(const std::string &includePath, const std::string &header)
{
    std::string path = includePath;
    if (!path.empty() && path[path.size()-1U]!='/' && path[path.size()-1U]!='\\')
        path += '/';
    return path + header;
}

static std::string openHeaderIncludePath(std::ifstream &f, const simplecpp::DUI &dui, const std::string &header)
{
    for (std::list<std::string>::const_iterator it = dui.includePaths.begin(); it != dui.includePaths.end(); ++it) {
        std::string simplePath = openHeader(f, getIncludePathFileName(*it, header));
        if (!simplePath.empty())
            return simplePath;
    }
    return "";
}

static std::string openHeader(std::ifstream &f, const simplecpp::DUI &dui, const std::string &sourcefile, const std::string &header, bool systemheader)
{
    if (isAbsolutePath(header))
        return openHeader(f, header);

    std::string ret;

    if (systemheader) {
        ret = openHeaderIncludePath(f, dui, header);
        return ret;
    }

    ret = openHeaderRelative(f, sourcefile, header);
    if (ret.empty())
        return openHeaderIncludePath(f, dui, header);
    return ret;
}

static std::string getFileName(const std::map<std::string, simplecpp::TokenList *> &filedata, const std::string &sourcefile, const std::string &header, const simplecpp::DUI &dui, bool systemheader)
{
    if (filedata.empty()) {
        return "";
    }
    if (isAbsolutePath(header)) {
        return (filedata.find(header) != filedata.end()) ? simplecpp::simplifyPath(header) : "";
    }

    const std::string relativeFilename = getRelativeFileName(sourcefile, header);
    if (!systemheader && filedata.find(relativeFilename) != filedata.end())
        return relativeFilename;

    for (std::list<std::string>::const_iterator it = dui.includePaths.begin(); it != dui.includePaths.end(); ++it) {
        std::string s = simplecpp::simplifyPath(getIncludePathFileName(*it, header));
        if (filedata.find(s) != filedata.end())
            return s;
    }

    if (systemheader && filedata.find(header) != filedata.end())
        return header;

    return "";
}

static bool hasFile(const std::map<std::string, simplecpp::TokenList *> &filedata, const std::string &sourcefile, const std::string &header, const simplecpp::DUI &dui, bool systemheader)
{
    return !getFileName(filedata, sourcefile, header, dui, systemheader).empty();
}

std::map<std::string, simplecpp::TokenList*> simplecpp::load(const simplecpp::TokenList &rawtokens, std::vector<std::string> &filenames, const simplecpp::DUI &dui, simplecpp::OutputList *outputList)
{
#ifdef SIMPLECPP_WINDOWS
    if (dui.clearIncludeCache)
        nonExistingFilesCache.clear();
#endif

    std::map<std::string, simplecpp::TokenList*> ret;

    std::list<const Token *> filelist;

    // -include files
    for (std::list<std::string>::const_iterator it = dui.includes.begin(); it != dui.includes.end(); ++it) {
        const std::string &filename = realFilename(*it);

        if (ret.find(filename) != ret.end())
            continue;

        std::ifstream fin(filename.c_str());
        if (!fin.is_open()) {
            if (outputList) {
                simplecpp::Output err(filenames);
                err.type = simplecpp::Output::EXPLICIT_INCLUDE_NOT_FOUND;
                err.location = Location(filenames);
                err.msg = "Can not open include file '" + filename + "' that is explicitly included.";
                outputList->push_back(err);
            }
            continue;
        }
        fin.close();

        TokenList *tokenlist = new TokenList(filename, filenames, outputList);
        if (!tokenlist->front()) {
            delete tokenlist;
            continue;
        }

        ret[filename] = tokenlist;
        filelist.push_back(tokenlist->front());
    }

    for (const Token *rawtok = rawtokens.cfront(); rawtok || !filelist.empty(); rawtok = rawtok ? rawtok->next : nullptr) {
        if (rawtok == nullptr) {
            rawtok = filelist.back();
            filelist.pop_back();
        }

        if (rawtok->op != '#' || sameline(rawtok->previousSkipComments(), rawtok))
            continue;

        rawtok = rawtok->nextSkipComments();
        if (!rawtok || rawtok->str() != INCLUDE)
            continue;

        const std::string &sourcefile = rawtok->location.file();

        const Token * const htok = rawtok->nextSkipComments();
        if (!sameline(rawtok, htok))
            continue;

        const bool systemheader = (htok->str()[0] == '<');
        const std::string header(realFilename(htok->str().substr(1U, htok->str().size() - 2U)));
        if (hasFile(ret, sourcefile, header, dui, systemheader))
            continue;

        std::ifstream f;
        const std::string header2 = openHeader(f,dui,sourcefile,header,systemheader);
        if (!f.is_open())
            continue;
        f.close();

        TokenList *tokens = new TokenList(header2, filenames, outputList);
        ret[header2] = tokens;
        if (tokens->front())
            filelist.push_back(tokens->front());
    }

    return ret;
}

static bool preprocessToken(simplecpp::TokenList &output, const simplecpp::Token **tok1, simplecpp::MacroMap &macros, std::vector<std::string> &files, simplecpp::OutputList *outputList)
{
    const simplecpp::Token * const tok = *tok1;
    const simplecpp::MacroMap::const_iterator it = macros.find(tok->str());
    if (it != macros.end()) {
        simplecpp::TokenList value(files);
        try {
            *tok1 = it->second.expand(&value, tok, macros, files);
        } catch (simplecpp::Macro::Error &err) {
            if (outputList) {
                simplecpp::Output out(files);
                out.type = simplecpp::Output::SYNTAX_ERROR;
                out.location = err.location;
                out.msg = "failed to expand \'" + tok->str() + "\', " + err.what;
                outputList->push_back(out);
            }
            return false;
        }
        output.takeTokens(value);
    } else {
        if (!tok->comment)
            output.push_back(new simplecpp::Token(*tok));
        *tok1 = tok->next;
    }
    return true;
}

static void getLocaltime(struct tm &ltime)
{
    time_t t;
    time(&t);
#ifndef _WIN32
    // NOLINTNEXTLINE(misc-include-cleaner) - false positive
    localtime_r(&t, &ltime);
#else
    localtime_s(&ltime, &t);
#endif
}

static std::string getDateDefine(const struct tm *timep)
{
    char buf[] = "??? ?? ????";
    strftime(buf, sizeof(buf), "%b %d %Y", timep);
    return std::string("\"").append(buf).append("\"");
}

static std::string getTimeDefine(const struct tm *timep)
{
    char buf[] = "??:??:??";
    strftime(buf, sizeof(buf), "%T", timep);
    return std::string("\"").append(buf).append("\"");
}

void simplecpp::preprocess(simplecpp::TokenList &output, const simplecpp::TokenList &rawtokens, std::vector<std::string> &files, std::map<std::string, simplecpp::TokenList *> &filedata, const simplecpp::DUI &dui, simplecpp::OutputList *outputList, std::list<simplecpp::MacroUsage> *macroUsage, std::list<simplecpp::IfCond> *ifCond)
{
#ifdef SIMPLECPP_WINDOWS
    if (dui.clearIncludeCache)
        nonExistingFilesCache.clear();
#endif

    std::map<std::string, std::size_t> sizeOfType(rawtokens.sizeOfType);
    sizeOfType.insert(std::make_pair("char", sizeof(char)));
    sizeOfType.insert(std::make_pair("short", sizeof(short)));
    sizeOfType.insert(std::make_pair("short int", sizeOfType["short"]));
    sizeOfType.insert(std::make_pair("int", sizeof(int)));
    sizeOfType.insert(std::make_pair("long", sizeof(long)));
    sizeOfType.insert(std::make_pair("long int", sizeOfType["long"]));
    sizeOfType.insert(std::make_pair("long long", sizeof(long long)));
    sizeOfType.insert(std::make_pair("float", sizeof(float)));
    sizeOfType.insert(std::make_pair("double", sizeof(double)));
    sizeOfType.insert(std::make_pair("long double", sizeof(long double)));
    sizeOfType.insert(std::make_pair("char *", sizeof(char *)));
    sizeOfType.insert(std::make_pair("short *", sizeof(short *)));
    sizeOfType.insert(std::make_pair("short int *", sizeOfType["short *"]));
    sizeOfType.insert(std::make_pair("int *", sizeof(int *)));
    sizeOfType.insert(std::make_pair("long *", sizeof(long *)));
    sizeOfType.insert(std::make_pair("long int *", sizeOfType["long *"]));
    sizeOfType.insert(std::make_pair("long long *", sizeof(long long *)));
    sizeOfType.insert(std::make_pair("float *", sizeof(float *)));
    sizeOfType.insert(std::make_pair("double *", sizeof(double *)));
    sizeOfType.insert(std::make_pair("long double *", sizeof(long double *)));

    const bool hasInclude = (dui.std.size() == 5 && dui.std.compare(0,3,"c++") == 0 && dui.std >= "c++17");
    MacroMap macros;
    for (std::list<std::string>::const_iterator it = dui.defines.begin(); it != dui.defines.end(); ++it) {
        const std::string &macrostr = *it;
        const std::string::size_type eq = macrostr.find('=');
        const std::string::size_type par = macrostr.find('(');
        const std::string macroname = macrostr.substr(0, std::min(eq,par));
        if (dui.undefined.find(macroname) != dui.undefined.end())
            continue;
        const std::string lhs(macrostr.substr(0,eq));
        const std::string rhs(eq==std::string::npos ? std::string("1") : macrostr.substr(eq+1));
        const Macro macro(lhs, rhs, files);
        macros.insert(std::pair<TokenString,Macro>(macro.name(), macro));
    }

    macros.insert(std::make_pair("__FILE__", Macro("__FILE__", "__FILE__", files)));
    macros.insert(std::make_pair("__LINE__", Macro("__LINE__", "__LINE__", files)));
    macros.insert(std::make_pair("__COUNTER__", Macro("__COUNTER__", "__COUNTER__", files)));
    struct tm ltime = {};
    getLocaltime(ltime);
    macros.insert(std::make_pair("__DATE__", Macro("__DATE__", getDateDefine(&ltime), files)));
    macros.insert(std::make_pair("__TIME__", Macro("__TIME__", getTimeDefine(&ltime), files)));

    if (!dui.std.empty()) {
        std::string std_def = simplecpp::getCStdString(dui.std);
        if (!std_def.empty()) {
            macros.insert(std::make_pair("__STDC_VERSION__", Macro("__STDC_VERSION__", std_def, files)));
        } else {
            std_def = simplecpp::getCppStdString(dui.std);
            if (!std_def.empty())
                macros.insert(std::make_pair("__cplusplus", Macro("__cplusplus", std_def, files)));
        }
    }

    // True => code in current #if block should be kept
    // ElseIsTrue => code in current #if block should be dropped. the code in the #else should be kept.
    // AlwaysFalse => drop all code in #if and #else
    enum IfState { True, ElseIsTrue, AlwaysFalse };
    std::stack<int> ifstates;
    ifstates.push(True);

    std::stack<const Token *> includetokenstack;

    std::set<std::string> pragmaOnce;

    includetokenstack.push(rawtokens.cfront());
    for (std::list<std::string>::const_iterator it = dui.includes.begin(); it != dui.includes.end(); ++it) {
        const std::map<std::string, TokenList*>::const_iterator f = filedata.find(*it);
        if (f != filedata.end())
            includetokenstack.push(f->second->cfront());
    }

    std::map<std::string, std::list<Location> > maybeUsedMacros;

    for (const Token *rawtok = nullptr; rawtok || !includetokenstack.empty();) {
        if (rawtok == nullptr) {
            rawtok = includetokenstack.top();
            includetokenstack.pop();
            continue;
        }

        if (rawtok->op == '#' && !sameline(rawtok->previousSkipComments(), rawtok)) {
            if (!sameline(rawtok, rawtok->next)) {
                rawtok = rawtok->next;
                continue;
            }
            rawtok = rawtok->next;
            if (!rawtok->name) {
                rawtok = gotoNextLine(rawtok);
                continue;
            }

            if (ifstates.size() <= 1U && (rawtok->str() == ELIF || rawtok->str() == ELSE || rawtok->str() == ENDIF)) {
                if (outputList) {
                    simplecpp::Output err(files);
                    err.type = Output::SYNTAX_ERROR;
                    err.location = rawtok->location;
                    err.msg = "#" + rawtok->str() + " without #if";
                    outputList->push_back(err);
                }
                output.clear();
                return;
            }

            if (ifstates.top() == True && (rawtok->str() == ERROR || rawtok->str() == WARNING)) {
                if (outputList) {
                    simplecpp::Output err(rawtok->location.files);
                    err.type = rawtok->str() == ERROR ? Output::ERROR : Output::WARNING;
                    err.location = rawtok->location;
                    for (const Token *tok = rawtok->next; tok && sameline(rawtok,tok); tok = tok->next) {
                        if (!err.msg.empty() && isNameChar(tok->str()[0]))
                            err.msg += ' ';
                        err.msg += tok->str();
                    }
                    err.msg = '#' + rawtok->str() + ' ' + err.msg;
                    outputList->push_back(err);
                }
                if (rawtok->str() == ERROR) {
                    output.clear();
                    return;
                }
            }

            if (rawtok->str() == DEFINE) {
                if (ifstates.top() != True)
                    continue;
                try {
                    const Macro &macro = Macro(rawtok->previous, files);
                    if (dui.undefined.find(macro.name()) == dui.undefined.end()) {
                        const MacroMap::iterator it = macros.find(macro.name());
                        if (it == macros.end())
                            macros.insert(std::pair<TokenString, Macro>(macro.name(), macro));
                        else
                            it->second = macro;
                    }
                } catch (const std::runtime_error &) {
                    if (outputList) {
                        simplecpp::Output err(files);
                        err.type = Output::SYNTAX_ERROR;
                        err.location = rawtok->location;
                        err.msg = "Failed to parse #define";
                        outputList->push_back(err);
                    }
                    output.clear();
                    return;
                }
            } else if (ifstates.top() == True && rawtok->str() == INCLUDE) {
                TokenList inc1(files);
                for (const Token *inctok = rawtok->next; sameline(rawtok,inctok); inctok = inctok->next) {
                    if (!inctok->comment)
                        inc1.push_back(new Token(*inctok));
                }
                TokenList inc2(files);
                if (!inc1.empty() && inc1.cfront()->name) {
                    const Token *inctok = inc1.cfront();
                    if (!preprocessToken(inc2, &inctok, macros, files, outputList)) {
                        output.clear();
                        return;
                    }
                } else {
                    inc2.takeTokens(inc1);
                }

                if (!inc2.empty() && inc2.cfront()->op == '<' && inc2.cback()->op == '>') {
                    TokenString hdr;
                    // TODO: Sometimes spaces must be added in the string
                    // Somehow preprocessToken etc must be told that the location should be source location not destination location
                    for (const Token *tok = inc2.cfront(); tok; tok = tok->next) {
                        hdr += tok->str();
                    }
                    inc2.clear();
                    inc2.push_back(new Token(hdr, inc1.cfront()->location));
                    inc2.front()->op = '<';
                }

                if (inc2.empty() || inc2.cfront()->str().size() <= 2U) {
                    if (outputList) {
                        simplecpp::Output err(files);
                        err.type = Output::SYNTAX_ERROR;
                        err.location = rawtok->location;
                        err.msg = "No header in #include";
                        outputList->push_back(err);
                    }
                    output.clear();
                    return;
                }

                const Token * const inctok = inc2.cfront();

                const bool systemheader = (inctok->str()[0] == '<');
                const std::string header(realFilename(inctok->str().substr(1U, inctok->str().size() - 2U)));
                std::string header2 = getFileName(filedata, rawtok->location.file(), header, dui, systemheader);
                if (header2.empty()) {
                    // try to load file..
                    std::ifstream f;
                    header2 = openHeader(f, dui, rawtok->location.file(), header, systemheader);
                    if (f.is_open()) {
                        TokenList * const tokens = new TokenList(f, files, header2, outputList);
                        filedata[header2] = tokens;
                    }
                }
                if (header2.empty()) {
                    if (outputList) {
                        simplecpp::Output out(files);
                        out.type = Output::MISSING_HEADER;
                        out.location = rawtok->location;
                        out.msg = "Header not found: " + inctok->str();
                        outputList->push_back(out);
                    }
                } else if (includetokenstack.size() >= 400) {
                    if (outputList) {
                        simplecpp::Output out(files);
                        out.type = Output::INCLUDE_NESTED_TOO_DEEPLY;
                        out.location = rawtok->location;
                        out.msg = "#include nested too deeply";
                        outputList->push_back(out);
                    }
                } else if (pragmaOnce.find(header2) == pragmaOnce.end()) {
                    includetokenstack.push(gotoNextLine(rawtok));
                    const TokenList * const includetokens = filedata.find(header2)->second;
                    rawtok = includetokens ? includetokens->cfront() : nullptr;
                    continue;
                }
            } else if (rawtok->str() == IF || rawtok->str() == IFDEF || rawtok->str() == IFNDEF || rawtok->str() == ELIF) {
                if (!sameline(rawtok,rawtok->next)) {
                    if (outputList) {
                        simplecpp::Output out(files);
                        out.type = Output::SYNTAX_ERROR;
                        out.location = rawtok->location;
                        out.msg = "Syntax error in #" + rawtok->str();
                        outputList->push_back(out);
                    }
                    output.clear();
                    return;
                }

                bool conditionIsTrue;
                if (ifstates.top() == AlwaysFalse || (ifstates.top() == ElseIsTrue && rawtok->str() != ELIF))
                    conditionIsTrue = false;
                else if (rawtok->str() == IFDEF) {
                    conditionIsTrue = (macros.find(rawtok->next->str()) != macros.end() || (hasInclude && rawtok->next->str() == HAS_INCLUDE));
                    maybeUsedMacros[rawtok->next->str()].push_back(rawtok->next->location);
                } else if (rawtok->str() == IFNDEF) {
                    conditionIsTrue = (macros.find(rawtok->next->str()) == macros.end() && !(hasInclude && rawtok->next->str() == HAS_INCLUDE));
                    maybeUsedMacros[rawtok->next->str()].push_back(rawtok->next->location);
                } else { /*if (rawtok->str() == IF || rawtok->str() == ELIF)*/
                    TokenList expr(files);
                    for (const Token *tok = rawtok->next; tok && tok->location.sameline(rawtok->location); tok = tok->next) {
                        if (!tok->name) {
                            expr.push_back(new Token(*tok));
                            continue;
                        }

                        if (tok->str() == DEFINED) {
                            tok = tok->next;
                            const bool par = (tok && tok->op == '(');
                            if (par)
                                tok = tok->next;
                            maybeUsedMacros[rawtok->next->str()].push_back(rawtok->next->location);
                            if (tok) {
                                if (macros.find(tok->str()) != macros.end())
                                    expr.push_back(new Token("1", tok->location));
                                else if (hasInclude && tok->str() == HAS_INCLUDE)
                                    expr.push_back(new Token("1", tok->location));
                                else
                                    expr.push_back(new Token("0", tok->location));
                            }
                            if (par)
                                tok = tok ? tok->next : nullptr;
                            if (!tok || !sameline(rawtok,tok) || (par && tok->op != ')')) {
                                if (outputList) {
                                    Output out(rawtok->location.files);
                                    out.type = Output::SYNTAX_ERROR;
                                    out.location = rawtok->location;
                                    out.msg = "failed to evaluate " + std::string(rawtok->str() == IF ? "#if" : "#elif") + " condition";
                                    outputList->push_back(out);
                                }
                                output.clear();
                                return;
                            }
                            continue;
                        }

                        if (hasInclude && tok->str() == HAS_INCLUDE) {
                            tok = tok->next;
                            const bool par = (tok && tok->op == '(');
                            if (par)
                                tok = tok->next;
                            bool closingAngularBracket = false;
                            if (tok) {
                                const std::string &sourcefile = rawtok->location.file();
                                const bool systemheader = (tok && tok->op == '<');
                                std::string header;

                                if (systemheader) {
                                    while ((tok = tok->next) && tok->op != '>')
                                        header += tok->str();
                                    // cppcheck-suppress selfAssignment - platform-dependent implementation
                                    header = realFilename(header);
                                    if (tok && tok->op == '>')
                                        closingAngularBracket = true;
                                }
                                else {
                                    header = realFilename(tok->str().substr(1U, tok->str().size() - 2U));
                                    closingAngularBracket = true;
                                }
                                std::ifstream f;
                                const std::string header2 = openHeader(f,dui,sourcefile,header,systemheader);
                                expr.push_back(new Token(header2.empty() ? "0" : "1", tok->location));
                            }
                            if (par)
                                tok = tok ? tok->next : nullptr;
                            if (!tok || !sameline(rawtok,tok) || (par && tok->op != ')') || (!closingAngularBracket)) {
                                if (outputList) {
                                    Output out(rawtok->location.files);
                                    out.type = Output::SYNTAX_ERROR;
                                    out.location = rawtok->location;
                                    out.msg = "failed to evaluate " + std::string(rawtok->str() == IF ? "#if" : "#elif") + " condition";
                                    outputList->push_back(out);
                                }
                                output.clear();
                                return;
                            }
                            continue;
                        }

                        maybeUsedMacros[rawtok->next->str()].push_back(rawtok->next->location);

                        const Token *tmp = tok;
                        if (!preprocessToken(expr, &tmp, macros, files, outputList)) {
                            output.clear();
                            return;
                        }
                        if (!tmp)
                            break;
                        tok = tmp->previous;
                    }
                    try {
                        if (ifCond) {
                            std::string E;
                            for (const simplecpp::Token *tok = expr.cfront(); tok; tok = tok->next)
                                E += (E.empty() ? "" : " ") + tok->str();
                            const long long result = evaluate(expr, dui, sizeOfType);
                            conditionIsTrue = (result != 0);
                            ifCond->push_back(IfCond(rawtok->location, E, result));
                        } else {
                            const long long result = evaluate(expr, dui, sizeOfType);
                            conditionIsTrue = (result != 0);
                        }
                    } catch (const std::exception &e) {
                        if (outputList) {
                            Output out(rawtok->location.files);
                            out.type = Output::SYNTAX_ERROR;
                            out.location = rawtok->location;
                            out.msg = "failed to evaluate " + std::string(rawtok->str() == IF ? "#if" : "#elif") + " condition";
                            if (e.what() && *e.what())
                                out.msg += std::string(", ") + e.what();
                            outputList->push_back(out);
                        }
                        output.clear();
                        return;
                    }
                }

                if (rawtok->str() != ELIF) {
                    // push a new ifstate..
                    if (ifstates.top() != True)
                        ifstates.push(AlwaysFalse);
                    else
                        ifstates.push(conditionIsTrue ? True : ElseIsTrue);
                } else if (ifstates.top() == True) {
                    ifstates.top() = AlwaysFalse;
                } else if (ifstates.top() == ElseIsTrue && conditionIsTrue) {
                    ifstates.top() = True;
                }
            } else if (rawtok->str() == ELSE) {
                ifstates.top() = (ifstates.top() == ElseIsTrue) ? True : AlwaysFalse;
            } else if (rawtok->str() == ENDIF) {
                ifstates.pop();
            } else if (rawtok->str() == UNDEF) {
                if (ifstates.top() == True) {
                    const Token *tok = rawtok->next;
                    while (sameline(rawtok,tok) && tok->comment)
                        tok = tok->next;
                    if (sameline(rawtok, tok))
                        macros.erase(tok->str());
                }
            } else if (ifstates.top() == True && rawtok->str() == PRAGMA && rawtok->next && rawtok->next->str() == ONCE && sameline(rawtok,rawtok->next)) {
                pragmaOnce.insert(rawtok->location.file());
            }
            rawtok = gotoNextLine(rawtok);
            continue;
        }

        if (ifstates.top() != True) {
            // drop code
            rawtok = gotoNextLine(rawtok);
            continue;
        }

        bool hash=false, hashhash=false;
        if (rawtok->op == '#' && sameline(rawtok,rawtok->next)) {
            if (rawtok->next->op != '#') {
                hash = true;
                rawtok = rawtok->next; // skip '#'
            } else if (sameline(rawtok,rawtok->next->next)) {
                hashhash = true;
                rawtok = rawtok->next->next; // skip '#' '#'
            }
        }

        const Location loc(rawtok->location);
        TokenList tokens(files);

        if (!preprocessToken(tokens, &rawtok, macros, files, outputList)) {
            output.clear();
            return;
        }

        if (hash || hashhash) {
            std::string s;
            for (const Token *hashtok = tokens.cfront(); hashtok; hashtok = hashtok->next)
                s += hashtok->str();
            if (hash)
                output.push_back(new Token('\"' + s + '\"', loc));
            else if (output.back())
                output.back()->setstr(output.cback()->str() + s);
            else
                output.push_back(new Token(s, loc));
        } else {
            output.takeTokens(tokens);
        }
    }

    if (macroUsage) {
        for (simplecpp::MacroMap::const_iterator macroIt = macros.begin(); macroIt != macros.end(); ++macroIt) {
            const Macro &macro = macroIt->second;
            std::list<Location> usage = macro.usage();
            const std::list<Location>& temp = maybeUsedMacros[macro.name()];
            usage.insert(usage.end(), temp.begin(), temp.end());
            for (std::list<Location>::const_iterator usageIt = usage.begin(); usageIt != usage.end(); ++usageIt) {
                MacroUsage mu(usageIt->files, macro.valueDefinedInCode());
                mu.macroName = macro.name();
                mu.macroLocation = macro.defineLocation();
                mu.useLocation = *usageIt;
                macroUsage->push_back(mu);
            }
        }
    }
}

void simplecpp::cleanup(std::map<std::string, TokenList*> &filedata)
{
    for (std::map<std::string, TokenList*>::iterator it = filedata.begin(); it != filedata.end(); ++it)
        delete it->second;
    filedata.clear();
}

std::string simplecpp::getCStdString(const std::string &std)
{
    if (std == "c90" || std == "c89" || std == "iso9899:1990" || std == "iso9899:199409" || std == "gnu90" || std == "gnu89") {
        // __STDC_VERSION__ is not set for C90 although the macro was added in the 1994 amendments
        return "";
    }
    if (std == "c99" || std == "c9x" || std == "iso9899:1999" || std == "iso9899:199x" || std == "gnu99"|| std == "gnu9x")
        return "199901L";
    if (std == "c11" || std == "c1x" || std == "iso9899:2011" || std == "gnu11" || std == "gnu1x")
        return "201112L";
    if (std == "c17" || std == "c18" || std == "iso9899:2017" || std == "iso9899:2018" || std == "gnu17"|| std == "gnu18")
        return "201710L";
    if (std == "c23" || std == "gnu23" || std == "c2x" || std == "gnu2x") {
        // supported by GCC 9+ and Clang 9+
        // Clang 9, 10, 11, 12, 13 return "201710L"
        // Clang 14, 15, 16, 17 return "202000L"
        // Clang 9, 10, 11, 12, 13, 14, 15, 16, 17 do not support "c23" and "gnu23"
        return "202311L";
    }
    return "";
}

std::string simplecpp::getCppStdString(const std::string &std)
{
    if (std == "c++98" || std == "c++03" || std == "gnu++98" || std == "gnu++03")
        return "199711L";
    if (std == "c++11" || std == "gnu++11" || std == "c++0x" || std == "gnu++0x")
        return "201103L";
    if (std == "c++14" || std == "c++1y" || std == "gnu++14" || std == "gnu++1y")
        return "201402L";
    if (std == "c++17" || std == "c++1z" || std == "gnu++17" || std == "gnu++1z")
        return "201703L";
    if (std == "c++20" || std == "c++2a" || std == "gnu++20" || std == "gnu++2a") {
        // GCC 10 returns "201703L" - correct in 11+
        return "202002L";
    }
    if (std == "c++23" || std == "c++2b" || std == "gnu++23" || std == "gnu++2b") {
        // supported by GCC 11+ and Clang 12+
        // GCC 11, 12, 13 return "202100L"
        // Clang 12, 13, 14, 15, 16 do not support "c++23" and "gnu++23" and return "202101L"
        // Clang 17, 18 return "202302L"
        return "202302L";
    }
    if (std == "c++26" || std == "c++2c" || std == "gnu++26" || std == "gnu++2c") {
        // supported by Clang 17+
        return "202400L";
    }
    return "";
}

#if (__cplusplus < 201103L) && !defined(__APPLE__)
#undef nullptr
#endif