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:heavy_check_mark: verify/utilities/parser.test.cpp

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Code

#define PROBLEM "https://judge.yosupo.jp/problem/aplusb"

#include "../../utilities/parser.hpp"

#include <cassert>
#include <cmath>
#include <cstdint>
#include "../../utilities/fast_io.hpp"
#include <iterator>
#include <limits>
#include <optional>
#include <string>
#include <string_view>
#include <utility>

namespace {

using m1une::utilities::ParseError;
using m1une::utilities::Parser;

void test_cursor_and_text() {
    Parser parser("  alpha::beta,tail");
    assert(parser.position() == 0);
    assert(parser.peek() == ' ');
    assert(parser.skip_whitespace() == 2);
    assert(parser.try_identifier() == std::optional<std::string_view>("alpha"));

    Parser::mark_type separator = parser.mark();
    assert(parser.consume("::"));
    assert(parser.identifier() == "beta");
    parser.restore(separator);
    assert(parser.remaining() == "::beta,tail");

    assert(parser.take(2) == std::optional<std::string_view>("::"));
    assert(parser.read_until(',', true) == "beta");
    assert(parser.remaining() == "tail");
    assert(!parser.take(5).has_value());
    assert(parser.remaining() == "tail");

    std::string_view letters = parser.read_while([](char character) {
        return 'a' <= character && character <= 'z';
    });
    assert(letters == "tail");
    assert(parser.eof());
    assert(!parser.peek().has_value());
}

void test_checkpoints() {
    Parser parser("first second");
    {
        auto attempt = parser.checkpoint();
        assert(parser.token() == "first");
    }
    assert(parser.position() == 0);

    {
        auto attempt = parser.checkpoint();
        assert(parser.token() == "first");
        attempt.commit();
    }
    assert(parser.position() == 5);

    {
        auto attempt = parser.checkpoint();
        assert(parser.token() == "second");
        attempt.rollback();
    }
    assert(parser.position() == 5);
}

void test_integers() {
    Parser parser(" -9223372036854775808 9223372036854775807 +255 ff 101101");
    assert(parser.integer<long long>() == std::numeric_limits<long long>::min());
    assert(parser.integer<long long>() == std::numeric_limits<long long>::max());
    assert(parser.integer<unsigned>() == 255U);
    assert(parser.integer<int>(16) == 255);
    assert(parser.integer<int>(2) == 45);

    Parser overflow(" 9223372036854775808");
    assert(!overflow.try_integer<long long>().has_value());
    assert(overflow.position() == 0);

    Parser negative_unsigned(" -1");
    assert(!negative_unsigned.try_integer<unsigned>().has_value());
    assert(negative_unsigned.position() == 0);

    Parser invalid(" + xyz");
    assert(!invalid.try_integer<int>().has_value());
    assert(invalid.position() == 0);

    bool rejected_base = false;
    try {
        (void)invalid.try_integer<int>(1);
    } catch (const std::invalid_argument&) {
        rejected_base = true;
    }
    assert(rejected_base);
}

void test_reals_and_balancing() {
    Parser parser(" -.5 12.25e2 3E-1 1e remainder");
    assert(std::abs(parser.real() + 0.5L) < 1e-18L);
    assert(std::abs(parser.real() - 1225.0L) < 1e-15L);
    assert(std::abs(parser.real() - 0.3L) < 1e-18L);
    assert(parser.real() == 1.0L);
    assert(parser.peek() == 'e');
    assert(parser.token() == "e");
    assert(parser.token() == "remainder");

    Parser nested(" [a[b]c] suffix");
    assert(nested.balanced('[', ']') == "a[b]c");
    assert(nested.token() == "suffix");

    Parser unclosed(" (abc");
    assert(!unclosed.try_balanced().has_value());
    assert(unclosed.position() == 0);

    bool caught = false;
    try {
        Parser bad("xyz");
        bad.expect("abc");
    } catch (const ParseError& error) {
        caught = true;
        assert(error.position() == 0);
    }
    assert(caught);
}

long long parse_expression(Parser& parser);

long long parse_atom(Parser& parser) {
    parser.skip_whitespace();
    if (parser.consume('(')) {
        long long value = parse_expression(parser);
        parser.skip_whitespace();
        parser.expect(')');
        return value;
    }
    return parser.integer<long long>();
}

long long parse_expression(Parser& parser) {
    long long value = parse_atom(parser);
    while (true) {
        parser.skip_whitespace();
        if (parser.consume('+')) {
            value += parse_atom(parser);
        } else if (parser.consume('-')) {
            value -= parse_atom(parser);
        } else {
            return value;
        }
    }
}

std::pair<std::string, long long> make_expression(std::uint64_t& state, int depth) {
    state ^= state << 7;
    state ^= state >> 9;
    if (depth == 0 || state % 4 == 0) {
        long long value = static_cast<long long>(state % 201) - 100;
        return std::make_pair(std::to_string(value), value);
    }

    std::pair<std::string, long long> left = make_expression(state, depth - 1);
    std::pair<std::string, long long> right = make_expression(state, depth - 1);
    bool add = (state >> 10) & 1;
    std::string text = "( " + left.first + (add ? " + " : " - ") + right.first + " )";
    long long value = add ? left.second + right.second : left.second - right.second;
    return std::make_pair(std::move(text), value);
}

void test_random_expressions() {
    std::uint64_t state = 0x123456789abcdefULL;
    for (int trial = 0; trial < 5000; ++trial) {
        std::pair<std::string, long long> generated = make_expression(state, 6);
        Parser parser(generated.first);
        assert(parse_expression(parser) == generated.second);
        parser.skip_whitespace();
        assert(parser.eof());
    }
}

void test_bulk_integer_parsing() {
    constexpr int count = 200000;
    std::string input;
    input.reserve(count * 5);
    long long expected = 0;
    for (int index = 0; index < count; ++index) {
        int value = index % 1000 - 500;
        input += std::to_string(value);
        input.push_back(index + 1 == count ? '\n' : ' ');
        expected += value;
    }

    Parser parser(input);
    long long actual = 0;
    for (int index = 0; index < count; ++index) {
        actual += parser.integer<int>();
    }
    parser.skip_whitespace();
    assert(parser.eof());
    assert(actual == expected);
}

}  // namespace

int main() {
    m1une::utilities::FastInput fast_input;
    m1une::utilities::FastOutput fast_output;

    test_cursor_and_text();
    test_checkpoints();
    test_integers();
    test_reals_and_balancing();
    test_random_expressions();
    test_bulk_integer_parsing();

    std::string input_text;
    int character = fast_input.read_char_raw();
    while (character != EOF) {
        input_text.push_back(char(character));
        character = fast_input.read_char_raw();
    }
    Parser parser(input_text);
    long long a = parser.integer<long long>();
    long long b = parser.integer<long long>();
    fast_output << a + b << '\n';
}
#line 1 "verify/utilities/parser.test.cpp"
#define PROBLEM "https://judge.yosupo.jp/problem/aplusb"

#line 1 "utilities/parser.hpp"



#include <cctype>
#include <cmath>
#include <cstddef>
#include <limits>
#include <optional>
#include <stdexcept>
#include <string>
#include <string_view>
#include <type_traits>
#include <utility>

namespace m1une {
namespace utilities {

class ParseError : public std::runtime_error {
private:
    std::size_t position_;

public:
    ParseError(std::size_t position, const std::string& message)
        : std::runtime_error(message + " at position " + std::to_string(position)),
          position_(position) {}

    [[nodiscard]] std::size_t position() const noexcept {
        return position_;
    }
};

class Parser {
public:
    using mark_type = std::size_t;

    class Checkpoint {
    private:
        Parser* parser_;
        mark_type position_;

    public:
        explicit Checkpoint(Parser& parser) noexcept
            : parser_(&parser), position_(parser.position()) {}

        Checkpoint(const Checkpoint&) = delete;
        Checkpoint& operator=(const Checkpoint&) = delete;

        Checkpoint(Checkpoint&& other) noexcept
            : parser_(std::exchange(other.parser_, nullptr)),
              position_(other.position_) {}

        Checkpoint& operator=(Checkpoint&&) = delete;

        ~Checkpoint() {
            rollback();
        }

        void commit() noexcept {
            parser_ = nullptr;
        }

        void rollback() noexcept {
            if (parser_ != nullptr) {
                parser_->position_ = position_;
                parser_ = nullptr;
            }
        }
    };

private:
    std::string_view input_;
    std::size_t position_ = 0;

    static int digit_value(char character) noexcept {
        if ('0' <= character && character <= '9') {
            return character - '0';
        }
        if ('a' <= character && character <= 'z') {
            return character - 'a' + 10;
        }
        if ('A' <= character && character <= 'Z') {
            return character - 'A' + 10;
        }
        return -1;
    }

    [[noreturn]] void fail(const std::string& message) const {
        throw ParseError(position_, message);
    }

public:
    Parser() = default;

    explicit Parser(std::string_view input) noexcept : input_(input) {}

    [[nodiscard]] std::string_view source() const noexcept {
        return input_;
    }

    [[nodiscard]] std::size_t size() const noexcept {
        return input_.size();
    }

    [[nodiscard]] std::size_t position() const noexcept {
        return position_;
    }

    [[nodiscard]] bool eof() const noexcept {
        return position_ == input_.size();
    }

    [[nodiscard]] std::string_view remaining() const noexcept {
        return input_.substr(position_);
    }

    [[nodiscard]] std::optional<char> peek(std::size_t offset = 0) const noexcept {
        if (offset >= input_.size() - position_) {
            return std::nullopt;
        }
        return input_[position_ + offset];
    }

    [[nodiscard]] mark_type mark() const noexcept {
        return position_;
    }

    void restore(mark_type saved_position) {
        if (saved_position > input_.size()) {
            throw std::out_of_range("parser position is outside the input");
        }
        position_ = saved_position;
    }

    [[nodiscard]] Checkpoint checkpoint() noexcept {
        return Checkpoint(*this);
    }

    template <typename Predicate>
    std::string_view read_while(Predicate predicate) {
        std::size_t begin = position_;
        while (!eof() && predicate(input_[position_])) {
            ++position_;
        }
        return input_.substr(begin, position_ - begin);
    }

    std::size_t skip_whitespace() noexcept {
        std::size_t begin = position_;
        while (!eof() && std::isspace(static_cast<unsigned char>(input_[position_]))) {
            ++position_;
        }
        return position_ - begin;
    }

    bool consume(char expected) noexcept {
        if (eof() || input_[position_] != expected) {
            return false;
        }
        ++position_;
        return true;
    }

    bool consume(std::string_view expected) noexcept {
        if (remaining().substr(0, expected.size()) != expected) {
            return false;
        }
        position_ += expected.size();
        return true;
    }

    template <typename Predicate>
    bool consume_if(Predicate predicate) {
        if (eof() || !predicate(input_[position_])) {
            return false;
        }
        ++position_;
        return true;
    }

    void expect(char expected) {
        if (!consume(expected)) {
            fail(std::string("expected '") + expected + "'");
        }
    }

    void expect(std::string_view expected) {
        if (!consume(expected)) {
            fail("expected \"" + std::string(expected) + "\"");
        }
    }

    std::optional<std::string_view> take(std::size_t count) noexcept {
        if (count > input_.size() - position_) {
            return std::nullopt;
        }
        std::string_view result = input_.substr(position_, count);
        position_ += count;
        return result;
    }

    std::string_view read_until(char delimiter, bool consume_delimiter = false) noexcept {
        std::size_t begin = position_;
        std::size_t found = input_.find(delimiter, position_);
        if (found == std::string_view::npos) {
            position_ = input_.size();
            return input_.substr(begin);
        }
        position_ = found + (consume_delimiter ? 1 : 0);
        return input_.substr(begin, found - begin);
    }

    std::optional<std::string_view> try_token() noexcept {
        mark_type begin_attempt = mark();
        skip_whitespace();
        std::size_t begin = position_;
        while (!eof() && !std::isspace(static_cast<unsigned char>(input_[position_]))) {
            ++position_;
        }
        if (begin == position_) {
            position_ = begin_attempt;
            return std::nullopt;
        }
        return input_.substr(begin, position_ - begin);
    }

    std::string_view token() {
        std::size_t error_position = position_;
        std::optional<std::string_view> result = try_token();
        if (!result.has_value()) {
            position_ = error_position;
            fail("expected token");
        }
        return *result;
    }

    std::optional<std::string_view> try_identifier() noexcept {
        mark_type begin_attempt = mark();
        skip_whitespace();
        if (eof()) {
            position_ = begin_attempt;
            return std::nullopt;
        }

        unsigned char first = static_cast<unsigned char>(input_[position_]);
        if (!(std::isalpha(first) || input_[position_] == '_')) {
            position_ = begin_attempt;
            return std::nullopt;
        }

        std::size_t begin = position_++;
        while (!eof()) {
            unsigned char current = static_cast<unsigned char>(input_[position_]);
            if (!(std::isalnum(current) || input_[position_] == '_')) {
                break;
            }
            ++position_;
        }
        return input_.substr(begin, position_ - begin);
    }

    std::string_view identifier() {
        std::size_t error_position = position_;
        std::optional<std::string_view> result = try_identifier();
        if (!result.has_value()) {
            position_ = error_position;
            fail("expected identifier");
        }
        return *result;
    }

    template <typename Integer>
    std::optional<Integer> try_integer(int base = 10) {
        static_assert(
            std::is_integral_v<Integer> && !std::is_same_v<Integer, bool>,
            "Integer must be a non-bool integral type"
        );
        if (base < 2 || base > 36) {
            throw std::invalid_argument("integer base must be in [2, 36]");
        }

        mark_type begin_attempt = mark();
        skip_whitespace();

        bool negative = false;
        if (consume('+')) {
            // The sign is already consumed.
        } else if (consume('-')) {
            if constexpr (std::is_unsigned_v<Integer>) {
                position_ = begin_attempt;
                return std::nullopt;
            } else {
                negative = true;
            }
        }

        using Unsigned = std::make_unsigned_t<Integer>;
        Unsigned limit = std::numeric_limits<Integer>::max();
        if constexpr (std::is_signed_v<Integer>) {
            if (negative) {
                limit += Unsigned(1);
            }
        }

        Unsigned value = 0;
        std::size_t digit_count = 0;
        while (!eof()) {
            int digit = digit_value(input_[position_]);
            if (digit < 0 || digit >= base) {
                break;
            }
            Unsigned unsigned_digit = static_cast<Unsigned>(digit);
            if (value > (limit - unsigned_digit) / static_cast<Unsigned>(base)) {
                position_ = begin_attempt;
                return std::nullopt;
            }
            value = value * static_cast<Unsigned>(base) + unsigned_digit;
            ++position_;
            ++digit_count;
        }

        if (digit_count == 0) {
            position_ = begin_attempt;
            return std::nullopt;
        }

        if constexpr (std::is_signed_v<Integer>) {
            if (negative) {
                if (value == static_cast<Unsigned>(std::numeric_limits<Integer>::max()) + 1) {
                    return std::numeric_limits<Integer>::min();
                }
                return static_cast<Integer>(-static_cast<Integer>(value));
            }
        }
        return static_cast<Integer>(value);
    }

    template <typename Integer>
    Integer integer(int base = 10) {
        std::size_t error_position = position_;
        std::optional<Integer> result = try_integer<Integer>(base);
        if (!result.has_value()) {
            position_ = error_position;
            fail("expected integer");
        }
        return *result;
    }

    std::optional<long double> try_real() noexcept {
        mark_type begin_attempt = mark();
        skip_whitespace();

        bool negative = false;
        if (consume('+')) {
            // The sign is already consumed.
        } else if (consume('-')) {
            negative = true;
        }

        long double value = 0;
        std::size_t digit_count = 0;
        while (!eof() && std::isdigit(static_cast<unsigned char>(input_[position_]))) {
            value = value * 10 + (input_[position_] - '0');
            ++position_;
            ++digit_count;
        }

        if (consume('.')) {
            long double place = 0.1L;
            while (!eof() && std::isdigit(static_cast<unsigned char>(input_[position_]))) {
                value += (input_[position_] - '0') * place;
                place *= 0.1L;
                ++position_;
                ++digit_count;
            }
        }

        if (digit_count == 0) {
            position_ = begin_attempt;
            return std::nullopt;
        }

        mark_type exponent_begin = mark();
        int exponent = 0;
        bool exponent_negative = false;
        if (consume('e') || consume('E')) {
            if (consume('+')) {
                // The sign is already consumed.
            } else if (consume('-')) {
                exponent_negative = true;
            }

            std::size_t exponent_digits = 0;
            while (!eof() && std::isdigit(static_cast<unsigned char>(input_[position_]))) {
                if (exponent < 1000000) {
                    exponent = exponent * 10 + (input_[position_] - '0');
                }
                ++position_;
                ++exponent_digits;
            }
            if (exponent_digits == 0) {
                position_ = exponent_begin;
                exponent = 0;
                exponent_negative = false;
            }
        }

        if (exponent != 0) {
            long double scale = std::pow(10.0L, exponent);
            value = exponent_negative ? value / scale : value * scale;
        }
        return negative ? -value : value;
    }

    long double real() {
        std::size_t error_position = position_;
        std::optional<long double> result = try_real();
        if (!result.has_value()) {
            position_ = error_position;
            fail("expected real number");
        }
        return *result;
    }

    std::optional<std::string_view> try_balanced(
        char opening = '(',
        char closing = ')'
    ) {
        if (opening == closing) {
            throw std::invalid_argument("balanced delimiters must be different");
        }

        mark_type begin_attempt = mark();
        skip_whitespace();
        if (!consume(opening)) {
            position_ = begin_attempt;
            return std::nullopt;
        }

        std::size_t content_begin = position_;
        int depth = 1;
        while (!eof()) {
            char current = input_[position_++];
            if (current == opening) {
                ++depth;
            } else if (current == closing) {
                --depth;
                if (depth == 0) {
                    return input_.substr(content_begin, position_ - content_begin - 1);
                }
            }
        }

        position_ = begin_attempt;
        return std::nullopt;
    }

    std::string_view balanced(char opening = '(', char closing = ')') {
        std::size_t error_position = position_;
        std::optional<std::string_view> result = try_balanced(opening, closing);
        if (!result.has_value()) {
            position_ = error_position;
            fail("expected balanced delimiters");
        }
        return *result;
    }
};

}  // namespace utilities
}  // namespace m1une


#line 4 "verify/utilities/parser.test.cpp"

#include <cassert>
#line 7 "verify/utilities/parser.test.cpp"
#include <cstdint>
#line 1 "utilities/fast_io.hpp"



#include <algorithm>
#include <array>
#include <cerrno>
#include <charconv>
#line 9 "utilities/fast_io.hpp"
#include <cstdio>
#include <cstdlib>
#line 12 "utilities/fast_io.hpp"
#include <cstring>
#include <iterator>
#line 15 "utilities/fast_io.hpp"
#include <sys/stat.h>
#line 18 "utilities/fast_io.hpp"
#include <unistd.h>
#include <vector>

namespace m1une {
namespace utilities {

struct FastOutput;

namespace internal {

// Shared with the convenience helpers in template.hpp.
inline FastOutput* standard_output_instance = nullptr;

// Detect std::begin(x), std::end(x).
template <class T, class = void>
struct is_range : std::false_type {};

template <class T>
struct is_range<T, std::void_t<
    decltype(std::begin(std::declval<T&>())),
    decltype(std::end(std::declval<T&>()))
>> : std::true_type {};

template <class T>
inline constexpr bool is_range_v = is_range<T>::value;

template <class T>
using range_reference_t = decltype(*std::begin(std::declval<T&>()));

template <class T>
using range_value_t = std::remove_cv_t<std::remove_reference_t<range_reference_t<T>>>;

template <class T, class = void>
struct range_stored_value {
    using type = range_value_t<T>;
};

template <class T>
struct range_stored_value<T, std::void_t<typename std::remove_cv_t<std::remove_reference_t<T>>::value_type>> {
    using type = typename std::remove_cv_t<std::remove_reference_t<T>>::value_type;
};

template <class T>
using range_stored_value_t = typename range_stored_value<T>::type;

// Treat strings and C strings as scalar output objects, not as ranges.
template <class T>
struct is_char_array : std::false_type {};

template <class T, std::size_t N>
struct is_char_array<T[N]>
    : std::bool_constant<std::is_same_v<std::remove_cv_t<T>, char>> {};

template <class T>
struct is_string_like
    : std::bool_constant<
          std::is_same_v<std::decay_t<T>, std::string>
          || std::is_same_v<std::decay_t<T>, const char*>
          || std::is_same_v<std::decay_t<T>, char*>
          || is_char_array<std::remove_reference_t<T>>::value
      > {};

template <class T>
inline constexpr bool is_string_like_v = is_string_like<T>::value;

// ModInt-like type: x.val() is printable, and x can be assigned from long long.
template <class T, class = void>
struct has_val_method : std::false_type {};

template <class T>
struct has_val_method<T, std::void_t<decltype(std::declval<const T&>().val())>>
    : std::true_type {};

template <class T>
inline constexpr bool has_val_method_v = has_val_method<T>::value;

template <class T, class = void>
struct has_static_mod_raw : std::false_type {};

template <class T>
struct has_static_mod_raw<
    T, std::void_t<decltype(T::mod()), decltype(T::raw(std::declval<uint32_t>()))>>
    : std::true_type {};

template <class T>
inline constexpr bool has_static_mod_raw_v = has_static_mod_raw<T>::value;

// libstdc++ before GCC 16 does not classify __int128 as an integral type in
// strict ISO modes such as -std=c++23. Keep the fast-I/O interface independent
// of that implementation detail.
template <class T>
inline constexpr bool is_integral_v =
    std::is_integral_v<T>
    || std::is_same_v<std::remove_cv_t<T>, __int128_t>
    || std::is_same_v<std::remove_cv_t<T>, __uint128_t>;

template <class T>
inline constexpr bool is_signed_v =
    std::is_signed_v<T>
    || std::is_same_v<std::remove_cv_t<T>, __int128_t>;

template <class T>
struct make_unsigned {
    using type = std::make_unsigned_t<T>;
};

template <>
struct make_unsigned<__int128_t> {
    using type = __uint128_t;
};

template <>
struct make_unsigned<__uint128_t> {
    using type = __uint128_t;
};

template <class T>
using make_unsigned_t = typename make_unsigned<std::remove_cv_t<T>>::type;

}  // namespace internal

struct FastInput {
    static constexpr int buffer_size = 1 << 20;

   private:
    std::FILE* _stream;
    char _buffer[buffer_size];
    int _position;
    int _length;
    int _file_descriptor;
    bool _streaming;

    bool refill() {
        _position = 0;
        if (_streaming) {
            ssize_t length;
            do {
                length = ::read(_file_descriptor, _buffer, buffer_size);
            } while (length < 0 && errno == EINTR);
            if (length <= 0) {
                _length = 0;
                return false;
            }
            _length = int(length);
        } else {
            _length = int(std::fread(_buffer, 1, buffer_size, _stream));
        }
        return _length != 0;
    }

    template <class T>
    bool read_integer_from_stream(T& value) {
        if (!skip_spaces()) return false;
        int c = read_char_raw();

        bool negative = false;
        if (c == '-') {
            negative = true;
            c = read_char_raw();
        }

        if constexpr (internal::is_signed_v<T>) {
            T result = 0;
            while ('0' <= c && c <= '9') {
                result = negative ? result * 10 - (c - '0')
                                  : result * 10 + (c - '0');
                c = read_char_raw();
            }
            value = result;
        } else {
            T result = 0;
            while ('0' <= c && c <= '9') {
                result = result * 10 + T(c - '0');
                c = read_char_raw();
            }
            value = negative ? T(0) - result : result;
        }
        return true;
    }

    bool prepare_number() {
        if (_length - _position >= 64) return true;
        const int remaining = _length - _position;
        if (remaining > 0) std::memmove(_buffer, _buffer + _position, remaining);
        const int added = int(std::fread(_buffer + remaining, 1, buffer_size - remaining, _stream));
        _position = 0;
        _length = remaining + added;
        if (_length < buffer_size) _buffer[_length] = '\0';
        return _length != 0;
    }

   public:
    explicit FastInput(std::FILE* stream = stdin)
        : _stream(stream),
          _position(0),
          _length(0),
          _file_descriptor(::fileno(stream)),
          _streaming([&] {
              struct stat status;
              return _file_descriptor >= 0
                     && ::fstat(_file_descriptor, &status) == 0
                     && !S_ISREG(status.st_mode);
          }()) {}

    FastInput(const FastInput&) = delete;
    FastInput& operator=(const FastInput&) = delete;

    int read_char_raw() {
        if (_position == _length && !refill()) return EOF;
        return _buffer[_position++];
    }

    bool skip_spaces() {
        int c = read_char_raw();
        while (c != EOF && c <= ' ') c = read_char_raw();
        if (c == EOF) return false;
        --_position;
        return true;
    }

    bool read(char& value) {
        if (!skip_spaces()) return false;
        value = char(read_char_raw());
        return true;
    }

    bool read(std::string& value) {
        if (!skip_spaces()) return false;
        value.clear();
        while (true) {
            const int begin = _position;
            while (_position < _length &&
                   static_cast<unsigned char>(_buffer[_position]) > ' ') {
                ++_position;
            }
            value.append(_buffer + begin, _position - begin);
            if (_position < _length) {
                ++_position;
                return true;
            }
            if (!refill()) return true;
        }
    }

    bool read(bool& value) {
        int x;
        if (!read(x)) return false;
        value = x != 0;
        return true;
    }

    template <class T>
    std::enable_if_t<
        internal::is_integral_v<T>
            && !std::is_same_v<std::remove_cv_t<T>, bool>
            && !std::is_same_v<std::remove_cv_t<T>, char>,
        bool
    >
    read(T& value) {
        if (_streaming) return read_integer_from_stream(value);
        if (!prepare_number()) return false;
        int c = static_cast<unsigned char>(_buffer[_position++]);
        while (c <= ' ') c = static_cast<unsigned char>(_buffer[_position++]);

        bool negative = false;
        if (c == '-') {
            negative = true;
            c = static_cast<unsigned char>(_buffer[_position++]);
        }

        if constexpr (internal::is_signed_v<T>) {
            T result = 0;
            while ('0' <= c && c <= '9') {
                const int first = c - '0';
                const int second = static_cast<unsigned char>(_buffer[_position]) - '0';
                if (0 <= second && second <= 9) {
                    result = negative ? result * 100 - (first * 10 + second)
                                      : result * 100 + (first * 10 + second);
                    ++_position;
                } else {
                    result = negative ? result * 10 - first : result * 10 + first;
                }
                c = static_cast<unsigned char>(_buffer[_position++]);
            }
            value = result;
        } else {
            T result = 0;
            while ('0' <= c && c <= '9') {
                const unsigned first = unsigned(c - '0');
                const int second = static_cast<unsigned char>(_buffer[_position]) - '0';
                if (0 <= second && second <= 9) {
                    result = result * 100 + T(first * 10 + unsigned(second));
                    ++_position;
                } else {
                    result = result * 10 + T(first);
                }
                c = static_cast<unsigned char>(_buffer[_position++]);
            }
            value = negative ? T(0) - result : result;
        }
        if (_position > _length) _position = _length;
        return true;
    }

    template <class T>
    std::enable_if_t<std::is_floating_point_v<T>, bool>
    read(T& value) {
        if (!skip_spaces()) return false;
        int c = read_char_raw();
        bool negative = false;
        if (c == '-' || c == '+') {
            negative = c == '-';
            c = read_char_raw();
        }

        long double result = 0;
        while ('0' <= c && c <= '9') {
            result = result * 10 + (c - '0');
            c = read_char_raw();
        }
        if (c == '.') {
            long double place = 0.1L;
            c = read_char_raw();
            while ('0' <= c && c <= '9') {
                result += (c - '0') * place;
                place *= 0.1L;
                c = read_char_raw();
            }
        }
        if (c == 'e' || c == 'E') {
            c = read_char_raw();
            bool exponent_negative = false;
            if (c == '-' || c == '+') {
                exponent_negative = c == '-';
                c = read_char_raw();
            }
            int exponent = 0;
            while ('0' <= c && c <= '9') {
                exponent = exponent * 10 + (c - '0');
                c = read_char_raw();
            }
            long double scale = 1;
            long double power = 10;
            while (exponent > 0) {
                if (exponent & 1) scale *= power;
                power *= power;
                exponent >>= 1;
            }
            result = exponent_negative ? result / scale : result * scale;
        }
        value = static_cast<T>(negative ? -result : result);
        return true;
    }

    template <class T>
    std::enable_if_t<
        internal::has_val_method_v<T>
            && !internal::is_integral_v<T>
            && !internal::is_range_v<T>,
        bool
    >
    read(T& value) {
        long long x;
        if (!read(x)) return false;
        if constexpr (internal::has_static_mod_raw_v<T>) {
            if (x >= 0 && uint64_t(x) < uint64_t(T::mod())) {
                value = T::raw(uint32_t(x));
            } else {
                value = T(x);
            }
        } else {
            value = T(x);
        }
        return true;
    }

    template <class First, class Second>
    bool read(std::pair<First, Second>& value) {
        if (!read(value.first)) return false;
        return read(value.second);
    }

    template <class Range>
    std::enable_if_t<
        internal::is_range_v<Range>
            && !internal::is_string_like_v<Range>,
        bool
    >
    read(Range& range) {
        using StoredValue = internal::range_stored_value_t<Range>;
        constexpr bool nested = internal::is_range_v<StoredValue>
                                && !internal::is_string_like_v<StoredValue>;

        for (auto&& value : range) {
            if constexpr (std::is_same_v<StoredValue, bool> && !nested) {
                bool x;
                if (!read(x)) return false;
                value = x;
            } else {
                if (!read(value)) return false;
            }
        }
        return true;
    }

    template <class First, class Second, class... Rest>
    bool read(First& first, Second& second, Rest&... rest) {
        if (!read(first)) return false;
        return read(second, rest...);
    }

    template <class T>
    FastInput& operator>>(T& value) {
        if (!read(value)) std::abort();
        return *this;
    }
};

struct FastOutput {
    static constexpr int buffer_size = 1 << 20;

   private:
    inline static const auto digit_quads = [] {
        std::array<char, 40000> result{};
        for (int i = 0; i < 10000; i++) {
            int value = i;
            for (int j = 3; j >= 0; j--) {
                result[4 * i + j] = char('0' + value % 10);
                value /= 10;
            }
        }
        return result;
    }();

    std::FILE* _stream;
    char _buffer[buffer_size];
    int _position;
    int _precision;
    std::chars_format _float_format;
    char _range_separator;
    std::string* _capture = nullptr;

    template <class T>
    std::string format_cell(const T& value) {
        std::string result;
        struct CaptureGuard {
            std::string*& target;
            std::string* previous;
            ~CaptureGuard() { target = previous; }
        } guard{_capture, _capture};
        _capture = &result;
        write(value);
        return result;
    }

    template <class Matrix>
    void write_aligned_matrix(const Matrix& matrix) {
        std::vector<std::vector<std::string>> rows;
        std::vector<std::size_t> widths;
        for (const auto& row : matrix) {
            auto& cells = rows.emplace_back();
            std::size_t column = 0;
            for (const auto& value : row) {
                cells.push_back(format_cell(value));
                if (column == widths.size()) widths.push_back(0);
                widths[column] = std::max(widths[column], cells.back().size());
                ++column;
            }
        }
        bool first = true;
        for (const auto& row : rows) {
            if (!first) write_char('\n');
            first = false;
            for (std::size_t column = 0; column < row.size(); ++column) {
                if (column != 0) write_char(_range_separator);
                for (std::size_t padding = row[column].size();
                     padding < widths[column]; ++padding) {
                    write_char(' ');
                }
                write(row[column]);
            }
        }
    }

   public:
    explicit FastOutput(std::FILE* stream = stdout)
        : _stream(stream),
          _position(0),
          _precision(6),
          _float_format(std::chars_format::general),
          _range_separator(' ') {
        if (_stream == stdout
            && internal::standard_output_instance == nullptr) {
            internal::standard_output_instance = this;
        }
    }

    FastOutput(const FastOutput&) = delete;
    FastOutput& operator=(const FastOutput&) = delete;

    ~FastOutput() {
        flush();
        if (internal::standard_output_instance == this) {
            internal::standard_output_instance = nullptr;
        }
    }

    void flush() {
        if (_position != 0) {
            std::fwrite(_buffer, 1, _position, _stream);
            _position = 0;
        }
        std::fflush(_stream);
    }

    void write_char(char c) {
        if (_capture != nullptr) {
            _capture->push_back(c);
            return;
        }
        if (_position == buffer_size) flush();
        _buffer[_position++] = c;
    }

    void write(const char* s) {
        while (*s != '\0') write_char(*s++);
    }

    void write(const std::string& s) {
        if (_capture != nullptr) {
            _capture->append(s);
            return;
        }
        std::size_t position = 0;
        while (position < s.size()) {
            if (_position == buffer_size) flush();
            const std::size_t copied =
                std::min<std::size_t>(buffer_size - _position, s.size() - position);
            std::memcpy(_buffer + _position, s.data() + position, copied);
            _position += int(copied);
            position += copied;
        }
    }

    void write(char c) {
        write_char(c);
    }

    void write(bool value) {
        write_char(value ? '1' : '0');
    }

    template <class T>
    std::enable_if_t<std::is_floating_point_v<T>>
    write(T value) {
        char digits[128];
        auto [end, error] = std::to_chars(
            digits,
            digits + sizeof(digits),
            value,
            _float_format,
            _precision
        );
        if (error != std::errc()) std::abort();
        for (const char* pointer = digits; pointer != end; pointer++) {
            write_char(*pointer);
        }
    }

    template <class T>
    std::enable_if_t<
        internal::is_integral_v<T>
            && !std::is_same_v<std::remove_cv_t<T>, bool>
            && !std::is_same_v<std::remove_cv_t<T>, char>
    >
    write(T value) {
        using Raw = std::remove_cv_t<T>;
        using Unsigned = internal::make_unsigned_t<Raw>;

        Unsigned magnitude;
        if constexpr (internal::is_signed_v<Raw>) {
            if (value < 0) {
                write_char('-');
                magnitude = Unsigned(0) - Unsigned(value);
            } else {
                magnitude = Unsigned(value);
            }
        } else {
            magnitude = value;
        }

        if (magnitude == 0) {
            write_char('0');
            return;
        }

        unsigned chunks[16];
        int count = 0;
        while (magnitude >= 10000) {
            const Unsigned quotient = magnitude / 10000;
            chunks[count++] = unsigned(magnitude - quotient * 10000);
            magnitude = quotient;
        }
        if (_capture == nullptr && _position > buffer_size - 64) flush();
        char captured[64];
        char* const begin = _capture != nullptr ? captured : _buffer + _position;
        char* destination = begin;
        const unsigned leading = unsigned(magnitude);
        const char* first = digit_quads.data() + 4 * leading;
        int skip = leading < 10 ? 3 : leading < 100 ? 2 : leading < 1000 ? 1 : 0;
        for (; skip < 4; skip++) *destination++ = first[skip];
        while (count--) {
            const char* digits = digit_quads.data() + 4 * chunks[count];
            std::memcpy(destination, digits, 4);
            destination += 4;
        }
        if (_capture != nullptr) {
            _capture->append(begin, destination - begin);
        } else {
            _position += int(destination - begin);
        }
    }

    template <class T>
    std::enable_if_t<
        internal::has_val_method_v<T>
            && !internal::is_integral_v<T>
            && !internal::is_range_v<T>
    >
    write(const T& value) {
        write(value.val());
    }

    template <class First, class Second>
    void write(const std::pair<First, Second>& value) {
        write(value.first);
        write_char(' ');
        write(value.second);
    }

    template <class Range>
    std::enable_if_t<
        internal::is_range_v<Range>
            && !internal::is_string_like_v<Range>
    >
    write(const Range& range) {
        using StoredValue = internal::range_stored_value_t<const Range>;
        constexpr bool nested = internal::is_range_v<StoredValue>
                                && !internal::is_string_like_v<StoredValue>;

        bool first = true;
        for (const auto& value : range) {
            if (!first) write_char(nested ? '\n' : _range_separator);
            first = false;
            if constexpr (std::is_same_v<StoredValue, bool> && !nested) {
                write(static_cast<bool>(value));
            } else {
                write(value);
            }
        }
    }

    template <class First, class... Rest>
    void print(const First& first, const Rest&... rest) {
        write(first);
        ((write_char(' '), write(rest)), ...);
    }

    void println() {
        write_char('\n');
    }

    void set_precision(int precision) {
        _precision = precision;
    }

    void set_fixed(int precision = 6) {
        _float_format = std::chars_format::fixed;
        _precision = precision;
    }

    void set_general(int precision = 6) {
        _float_format = std::chars_format::general;
        _precision = precision;
    }

    void set_range_separator(char separator) {
        _range_separator = separator;
    }

    template <class Matrix>
    void write_aligned(const Matrix& matrix) {
        using Row = internal::range_stored_value_t<const Matrix>;
        using Cell = internal::range_stored_value_t<const Row>;
        static_assert(internal::is_range_v<Row> && !internal::is_string_like_v<Row>,
                      "write_aligned requires a two-dimensional range");
        static_assert(!internal::is_range_v<Cell> || internal::is_string_like_v<Cell>,
                      "write_aligned requires scalar cells");
        write_aligned_matrix(matrix);
    }

    template <class Matrix>
    void println_aligned(const Matrix& matrix) {
        write_aligned(matrix);
        write_char('\n');
    }

    template <class... Args>
    void println(const Args&... args) {
        print(args...);
        write_char('\n');
    }

    template <class T>
    FastOutput& operator<<(const T& value) {
        write(value);
        return *this;
    }
};

}  // namespace utilities
}  // namespace m1une


#line 15 "verify/utilities/parser.test.cpp"

namespace {

using m1une::utilities::ParseError;
using m1une::utilities::Parser;

void test_cursor_and_text() {
    Parser parser("  alpha::beta,tail");
    assert(parser.position() == 0);
    assert(parser.peek() == ' ');
    assert(parser.skip_whitespace() == 2);
    assert(parser.try_identifier() == std::optional<std::string_view>("alpha"));

    Parser::mark_type separator = parser.mark();
    assert(parser.consume("::"));
    assert(parser.identifier() == "beta");
    parser.restore(separator);
    assert(parser.remaining() == "::beta,tail");

    assert(parser.take(2) == std::optional<std::string_view>("::"));
    assert(parser.read_until(',', true) == "beta");
    assert(parser.remaining() == "tail");
    assert(!parser.take(5).has_value());
    assert(parser.remaining() == "tail");

    std::string_view letters = parser.read_while([](char character) {
        return 'a' <= character && character <= 'z';
    });
    assert(letters == "tail");
    assert(parser.eof());
    assert(!parser.peek().has_value());
}

void test_checkpoints() {
    Parser parser("first second");
    {
        auto attempt = parser.checkpoint();
        assert(parser.token() == "first");
    }
    assert(parser.position() == 0);

    {
        auto attempt = parser.checkpoint();
        assert(parser.token() == "first");
        attempt.commit();
    }
    assert(parser.position() == 5);

    {
        auto attempt = parser.checkpoint();
        assert(parser.token() == "second");
        attempt.rollback();
    }
    assert(parser.position() == 5);
}

void test_integers() {
    Parser parser(" -9223372036854775808 9223372036854775807 +255 ff 101101");
    assert(parser.integer<long long>() == std::numeric_limits<long long>::min());
    assert(parser.integer<long long>() == std::numeric_limits<long long>::max());
    assert(parser.integer<unsigned>() == 255U);
    assert(parser.integer<int>(16) == 255);
    assert(parser.integer<int>(2) == 45);

    Parser overflow(" 9223372036854775808");
    assert(!overflow.try_integer<long long>().has_value());
    assert(overflow.position() == 0);

    Parser negative_unsigned(" -1");
    assert(!negative_unsigned.try_integer<unsigned>().has_value());
    assert(negative_unsigned.position() == 0);

    Parser invalid(" + xyz");
    assert(!invalid.try_integer<int>().has_value());
    assert(invalid.position() == 0);

    bool rejected_base = false;
    try {
        (void)invalid.try_integer<int>(1);
    } catch (const std::invalid_argument&) {
        rejected_base = true;
    }
    assert(rejected_base);
}

void test_reals_and_balancing() {
    Parser parser(" -.5 12.25e2 3E-1 1e remainder");
    assert(std::abs(parser.real() + 0.5L) < 1e-18L);
    assert(std::abs(parser.real() - 1225.0L) < 1e-15L);
    assert(std::abs(parser.real() - 0.3L) < 1e-18L);
    assert(parser.real() == 1.0L);
    assert(parser.peek() == 'e');
    assert(parser.token() == "e");
    assert(parser.token() == "remainder");

    Parser nested(" [a[b]c] suffix");
    assert(nested.balanced('[', ']') == "a[b]c");
    assert(nested.token() == "suffix");

    Parser unclosed(" (abc");
    assert(!unclosed.try_balanced().has_value());
    assert(unclosed.position() == 0);

    bool caught = false;
    try {
        Parser bad("xyz");
        bad.expect("abc");
    } catch (const ParseError& error) {
        caught = true;
        assert(error.position() == 0);
    }
    assert(caught);
}

long long parse_expression(Parser& parser);

long long parse_atom(Parser& parser) {
    parser.skip_whitespace();
    if (parser.consume('(')) {
        long long value = parse_expression(parser);
        parser.skip_whitespace();
        parser.expect(')');
        return value;
    }
    return parser.integer<long long>();
}

long long parse_expression(Parser& parser) {
    long long value = parse_atom(parser);
    while (true) {
        parser.skip_whitespace();
        if (parser.consume('+')) {
            value += parse_atom(parser);
        } else if (parser.consume('-')) {
            value -= parse_atom(parser);
        } else {
            return value;
        }
    }
}

std::pair<std::string, long long> make_expression(std::uint64_t& state, int depth) {
    state ^= state << 7;
    state ^= state >> 9;
    if (depth == 0 || state % 4 == 0) {
        long long value = static_cast<long long>(state % 201) - 100;
        return std::make_pair(std::to_string(value), value);
    }

    std::pair<std::string, long long> left = make_expression(state, depth - 1);
    std::pair<std::string, long long> right = make_expression(state, depth - 1);
    bool add = (state >> 10) & 1;
    std::string text = "( " + left.first + (add ? " + " : " - ") + right.first + " )";
    long long value = add ? left.second + right.second : left.second - right.second;
    return std::make_pair(std::move(text), value);
}

void test_random_expressions() {
    std::uint64_t state = 0x123456789abcdefULL;
    for (int trial = 0; trial < 5000; ++trial) {
        std::pair<std::string, long long> generated = make_expression(state, 6);
        Parser parser(generated.first);
        assert(parse_expression(parser) == generated.second);
        parser.skip_whitespace();
        assert(parser.eof());
    }
}

void test_bulk_integer_parsing() {
    constexpr int count = 200000;
    std::string input;
    input.reserve(count * 5);
    long long expected = 0;
    for (int index = 0; index < count; ++index) {
        int value = index % 1000 - 500;
        input += std::to_string(value);
        input.push_back(index + 1 == count ? '\n' : ' ');
        expected += value;
    }

    Parser parser(input);
    long long actual = 0;
    for (int index = 0; index < count; ++index) {
        actual += parser.integer<int>();
    }
    parser.skip_whitespace();
    assert(parser.eof());
    assert(actual == expected);
}

}  // namespace

int main() {
    m1une::utilities::FastInput fast_input;
    m1une::utilities::FastOutput fast_output;

    test_cursor_and_text();
    test_checkpoints();
    test_integers();
    test_reals_and_balancing();
    test_random_expressions();
    test_bulk_integer_parsing();

    std::string input_text;
    int character = fast_input.read_char_raw();
    while (character != EOF) {
        input_text.push_back(char(character));
        character = fast_input.read_char_raw();
    }
    Parser parser(input_text);
    long long a = parser.integer<long long>();
    long long b = parser.integer<long long>();
    fast_output << a + b << '\n';
}
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