// Copyright (c) 2009-2014 The Bitcoin Core developers
// Copyright (c) 2017-2020 The Bitcoin developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#include <list>
#include <locale>
#include <stdexcept>
#include <tuple>

namespace {
// trigger: use ctype<char>::widen to trigger ctype<char>::_M_widen_init().
// test: convert a char from narrow to wide and back. Verify that the result
//   matches the original.
bool sanity_test_widen(char testchar) {
    const std::ctype<char> &test(
        std::use_facet<std::ctype<char>>(std::locale()));
    return test.narrow(test.widen(testchar), 'b') == testchar;
}

// trigger: use list::push_back and list::pop_back to trigger _M_hook and
//   _M_unhook.
// test: Push a sequence of integers into a list. Pop them off and verify that
//   they match the original sequence.
bool sanity_test_list(unsigned int size) {
    std::list<unsigned int> test;
    for (unsigned int i = 0; i != size; ++i) {
        test.push_back(i + 1);
    }

    if (test.size() != size) {
        return false;
    }

    while (!test.empty()) {
        if (test.back() != test.size()) {
            return false;
        }
        test.pop_back();
    }
    return true;
}

} // namespace

// trigger: string::at(x) on an empty string to trigger
// __throw_out_of_range_fmt.
// test: force std::string to throw an out_of_range exception. Verify that
//   it's caught correctly.
bool sanity_test_range_fmt() {
    std::string test;
    try {
        /* sometimes .at() is [[nodiscard]] */
        std::ignore = test.at(1);
    } catch (const std::out_of_range &) {
        return true;
    } catch (...) {
    }
    return false;
}

bool glibcxx_sanity_test() {
    return sanity_test_widen('a') && sanity_test_list(100) &&
           sanity_test_range_fmt();
}
