preproc2

#include <cassert>
#include <filesystem>
#include <fstream>
#include <iostream>
#include <regex>
#include <sstream>
#include <string>
#include <vector>
using namespace std;
using filesystem::path;

path operator""_p(const char* data, std::size_t sz) {
    return path(data, data + sz);
}


string obpath(path in_file) {

    string obspath = in_file.string();

    for (int i = obspath.size() - 1; i > 0 - 1; i--) {
        if (obspath[i] != '\\' && obspath[i] != '/') {
            obspath.resize(i);
        }
        else {
            break;
        }
    }
    return obspath;
}

// напишите эту функцию
bool Preprocess(const path& in_file, const path& out_file, const vector<path>& include_directories) {

    ifstream input(in_file);
    if (!input.is_open()) {
        return false;
    }

    ofstream out(out_file);
    smatch coincidences;
    regex local_reg(R"/(\s*#\s*include\s*"([^"]*)"\s*)/");
    regex remote_reg(R"/(\s*#\s*include\s*<([^>]*)>\s*)/");

    string line;
    int number_line = 0;
    while (getline(input, line)) {
        number_line += 1;
        if (regex_match(line, coincidences, local_reg)) {
            if (coincidences.size() > 1) {
                string obspath = obpath(in_file);
                obspath += coincidences[1];
                string p2 = "sources\\include2\\";
                p2 += coincidences[1];
                if (filesystem::exists(obspath)) {
                    //когда нашли файл
                    Preprocess(obspath, out_file, include_directories);

                }
                else if(filesystem::exists(p2)) {
                    Preprocess(p2, out_file, include_directories);
                }
                else {
                    cout << "unknown include file "<< coincidences[1] << " at file "<< in_file.string() << " at line " << number_line << endl;
                    return false;
                }
            }
        }
        else if (regex_match(line, coincidences, remote_reg)) {
            if (coincidences.size() > 1) {
                string p = "sources\\include1\\";
                p += coincidences[1];
                if (filesystem::exists(p)) {
                    //когда нашли файл
                    Preprocess(p, out_file, include_directories);
                }
                else {
                    cout << "unknown include file " << coincidences[1] << " at file " << in_file.string() << " at line " << number_line << endl;
                    return false;
                }
            }
        }
        else {
            cout << line << endl;
        }
    }
    return true;

}




string GetFileContents(string file) {
    ifstream stream(file);

    // конструируем string по двум итераторам
    return { (istreambuf_iterator<char>(stream)), istreambuf_iterator<char>() };
}

void Test() {
    error_code err;
    filesystem::remove_all("sources"_p, err);
    filesystem::create_directories("sources"_p / "include2"_p / "lib"_p, err);
    filesystem::create_directories("sources"_p / "include1"_p, err);
    filesystem::create_directories("sources"_p / "dir1"_p / "subdir"_p, err);

    {
        ofstream file("sources/a.cpp");
        file << "// this comment before include\n"
            "#include \"dir1/b.h\"\n"
            "// text between b.h and c.h\n"
            "#include \"dir1/d.h\"\n"
            "\n"
            "int SayHello() {\n"
            "    cout << \"hello, world!\" << endl;\n"
            "#   include<dummy.txt>\n"
            "}\n"s;
    }
    {
        ofstream file("sources/dir1/b.h");
        file << "// text from b.h before include\n"
            "#include \"subdir/c.h\"\n"
            "// text from b.h after include"s;
    }
    {
        ofstream file("sources/dir1/subdir/c.h");
        file << "// text from c.h before include\n"
            "#include <std1.h>\n"
            "// text from c.h after include\n"s;
    }
    {
        ofstream file("sources/dir1/d.h");
        file << "// text from d.h before include\n"
            "#include \"lib/std2.h\"\n"
            "// text from d.h after include\n"s;
    }
    {
        ofstream file("sources/include1/std1.h");
        file << "// std1\n"s;
    }
    {
        ofstream file("sources/include2/lib/std2.h");
        file << "// std2\n"s;
    }

    assert((!Preprocess("sources"_p / "a.cpp"_p, "sources"_p / "a.in"_p,
        { "sources"_p / "include1"_p,"sources"_p / "include2"_p })));

    ostringstream test_out;
    test_out << "// this comment before include\n"
        "// text from b.h before include\n"
        "// text from c.h before include\n"
        "// std1\n"
        "// text from c.h after include\n"
        "// text from b.h after include\n"
        "// text between b.h and c.h\n"
        "// text from d.h before include\n"
        "// std2\n"
        "// text from d.h after include\n"
        "\n"
        "int SayHello() {\n"
        "    cout << \"hello, world!\" << endl;\n"s;

    assert(GetFileContents("sources/a.in"s) == test_out.str());
}

int main() {
    Test();
}