add C++11-compatible replacement for std::string_view
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cad377d3a1
1 changed files with 86 additions and 46 deletions
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@ -40,6 +40,45 @@ static std::string build_repetition(const std::string & item_rule, const int min
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return result;
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}
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/* Minimalistic replacement for std::string_view, which is only available from C++17 onwards */
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class string_view {
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const std::string & _str;
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const size_t _start;
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const size_t _end;
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public:
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string_view(const std::string & str, size_t start = 0, size_t end = std::string::npos) : _str(str), _start(start), _end(end == std::string::npos ? str.length() : end) {}
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size_t size() const {
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return _end - _start;
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}
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size_t length() const {
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return size();
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}
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operator std::string() const {
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return str();
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}
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std::string str() const {
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return _str.substr(_start, _end - _start);
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}
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string_view substr(size_t pos, size_t len = std::string::npos) const {
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return string_view(_str, _start + pos, len == std::string::npos ? _end : _start + pos + len);
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}
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char operator[](size_t pos) const {
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return _str[_start + pos];
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}
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bool operator==(const string_view & other) const {
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std::string this_str = *this;
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std::string other_str = other;
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return this_str == other_str;
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}
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};
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static void _build_min_max_int(int min_value, int max_value, std::stringstream & out, int decimals_left = 16, bool top_level = true) {
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auto has_min = min_value != std::numeric_limits<int>::min();
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auto has_max = max_value != std::numeric_limits<int>::max();
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@ -68,60 +107,61 @@ static void _build_min_max_int(int min_value, int max_value, std::stringstream &
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}
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out << "}";
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};
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std::function<void(const std::string_view &, const std::string_view &)> uniform_range = [&](const std::string_view & from, const std::string_view & to) {
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size_t i = 0;
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while (from[i] == to[i]) {
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i++;
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}
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if (i > 0) {
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out << "\"" << from.substr(0, i) << "\"";
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}
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if (i < from.length()) {
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if (i > 0) {
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out << " ";
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std::function<void(const string_view &, const string_view &)> uniform_range =
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[&](const string_view & from, const string_view & to) {
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size_t i = 0;
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while (from[i] == to[i]) {
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i++;
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}
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auto sub_len = from.length() - i - 1;
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if (sub_len > 0) {
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auto from_sub = from.substr(i + 1);
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auto to_sub = to.substr(i + 1);
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auto sub_zeros = repeat("0", sub_len);
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auto sub_nines = repeat("9", sub_len);
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auto to_reached = false;
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out << "(";
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if (from_sub == sub_zeros) {
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digit_range(from[i], to[i] - 1);
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if (i > 0) {
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out << "\"" << from.substr(0, i).str() << "\"";
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}
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if (i < from.length()) {
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if (i > 0) {
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out << " ";
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more_digits(sub_len, sub_len);
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} else {
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out << "[" << from[i] << "] ";
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}
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auto sub_len = from.length() - i - 1;
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if (sub_len > 0) {
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auto from_sub = from.substr(i + 1);
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auto to_sub = to.substr(i + 1);
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auto sub_zeros = repeat("0", sub_len);
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auto sub_nines = repeat("9", sub_len);
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auto to_reached = false;
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out << "(";
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uniform_range(from_sub, sub_nines);
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out << ")";
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if (from[i] < to[i] - 1) {
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out << " | ";
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if (to_sub == sub_nines) {
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digit_range(from[i] + 1, to[i]);
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to_reached = true;
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} else {
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digit_range(from[i] + 1, to[i] - 1);
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}
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if (from_sub == sub_zeros) {
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digit_range(from[i], to[i] - 1);
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out << " ";
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more_digits(sub_len, sub_len);
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} else {
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out << "[" << from[i] << "] ";
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out << "(";
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uniform_range(from_sub, sub_nines);
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out << ")";
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if (from[i] < to[i] - 1) {
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out << " | ";
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if (to_sub == sub_nines) {
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digit_range(from[i] + 1, to[i]);
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to_reached = true;
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} else {
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digit_range(from[i] + 1, to[i] - 1);
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}
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out << " ";
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more_digits(sub_len, sub_len);
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}
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}
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if (!to_reached) {
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out << " | ";
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digit_range(to[i], to[i]);
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out << " ";
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uniform_range(sub_zeros, to_sub);
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}
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out << ")";
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} else {
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out << "[" << from[i] << "-" << to[i] << "]";
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}
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if (!to_reached) {
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out << " | ";
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digit_range(to[i], to[i]);
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out << " ";
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uniform_range(sub_zeros, to_sub);
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}
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out << ")";
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} else {
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out << "[" << from[i] << "-" << to[i] << "]";
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}
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}
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};
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};
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if (has_min && has_max) {
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if (min_value < 0 && max_value < 0) {
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