From 9fa9edb24d762866c49755f71204194c5a075202 Mon Sep 17 00:00:00 2001
From: ado <adnan.abd0124@gmail.com>
Date: Wed, 30 Mar 2022 20:11:55 +0200
Subject: [PATCH] add spp.hpp

---
 include/ss/extract.hpp |    1 -
 ssp.hpp                | 2967 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 2967 insertions(+), 1 deletion(-)
 create mode 100644 ssp.hpp

diff --git a/include/ss/extract.hpp b/include/ss/extract.hpp
index ae2d81c..760aca8 100644
--- a/include/ss/extract.hpp
+++ b/include/ss/extract.hpp
@@ -5,7 +5,6 @@
 #include <functional>
 #include <limits>
 #include <optional>
-#include <stdexcept>
 #include <string>
 #include <string_view>
 #include <variant>
diff --git a/ssp.hpp b/ssp.hpp
new file mode 100644
index 0000000..b49906b
--- /dev/null
+++ b/ssp.hpp
@@ -0,0 +1,2967 @@
+#include <algorithm>
+#include <array>
+#include <charconv>
+#include <cstdint>
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include <functional>
+#include <limits>
+#include <memory>
+#include <optional>
+#include <string>
+#include <string_view>
+#include <tuple>
+#include <type_traits>
+#include <variant>
+#include <vector>
+#define SSP_DISABLE_FAST_FLOAT
+
+
+namespace ss {
+
+////////////////
+// tup merge/cat
+////////////////
+
+template <typename T, typename Ts>
+struct tup_cat;
+
+template <typename... Ts, typename... Us>
+struct tup_cat<std::tuple<Ts...>, std::tuple<Us...>> {
+    using type = std::tuple<Ts..., Us...>;
+};
+
+template <typename T, typename... Ts>
+struct tup_cat<T, std::tuple<Ts...>> {
+    using type = std::tuple<T, Ts...>;
+};
+
+template <typename... Ts>
+using tup_cat_t = typename tup_cat<Ts...>::type;
+
+////////////////
+// tup first/head
+////////////////
+
+template <size_t N, typename T, typename... Ts>
+struct left_of_impl;
+
+template <size_t N, typename T, typename... Ts>
+struct left_of_impl {
+    static_assert(N < 128, "recursion limit reached");
+    static_assert(N != 0, "cannot take the whole tuple");
+    using type = tup_cat_t<T, typename left_of_impl<N - 1, Ts...>::type>;
+};
+
+template <typename T, typename... Ts>
+struct left_of_impl<0, T, Ts...> {
+    using type = std::tuple<T>;
+};
+
+template <size_t N, typename... Ts>
+using left_of_t = typename left_of_impl<N, Ts...>::type;
+
+template <typename... Ts>
+using first_t = typename left_of_impl<sizeof...(Ts) - 2, Ts...>::type;
+
+template <typename... Ts>
+using head_t = typename left_of_impl<0, Ts...>::type;
+
+////////////////
+// tup tail/last
+////////////////
+
+template <size_t N, typename T, typename... Ts>
+struct right_of_impl;
+
+template <size_t N, typename T, typename... Ts>
+struct right_of_impl {
+    using type = typename right_of_impl<N - 1, Ts...>::type;
+};
+
+template <typename T, typename... Ts>
+struct right_of_impl<0, T, Ts...> {
+    using type = std::tuple<T, Ts...>;
+};
+
+template <size_t N, typename... Ts>
+using right_of_t = typename right_of_impl<N, Ts...>::type;
+
+template <typename... Ts>
+using tail_t = typename right_of_impl<1, Ts...>::type;
+
+template <typename... Ts>
+using last_t = typename right_of_impl<sizeof...(Ts) - 1, Ts...>::type;
+
+////////////////
+// apply trait
+////////////////
+
+template <template <typename...> class Trait, typename T>
+struct apply_trait;
+
+template <template <typename...> class Trait, typename T, typename... Ts>
+struct apply_trait<Trait, std::tuple<T, Ts...>> {
+    using type =
+        tup_cat_t<typename Trait<T>::type,
+                  typename apply_trait<Trait, std::tuple<Ts...>>::type>;
+};
+
+template <template <typename...> class Trait, typename T>
+struct apply_trait {
+    using type = std::tuple<typename Trait<T>::type>;
+};
+
+template <template <typename...> class Trait, typename T>
+struct apply_trait<Trait, std::tuple<T>> {
+    using type = std::tuple<typename Trait<T>::type>;
+};
+
+template <template <typename...> class Trait, typename... Ts>
+using apply_trait_t = typename apply_trait<Trait, Ts...>::type;
+
+////////////////
+// apply optional trait
+////////////////
+
+// type is T if true, and std::false_type othervise
+template <typename T, typename U>
+struct optional_trait;
+
+template <typename U>
+struct optional_trait<std::true_type, U> {
+    using type = U;
+};
+
+template <typename U>
+struct optional_trait<std::false_type, U> {
+    using type = std::false_type;
+};
+
+template <template <typename...> class Trait, typename T>
+struct apply_optional_trait;
+
+template <template <typename...> class Trait, typename T, typename... Ts>
+struct apply_optional_trait<Trait, std::tuple<T, Ts...>> {
+    using type = tup_cat_t<
+        typename optional_trait<typename Trait<T>::type, T>::type,
+        typename apply_optional_trait<Trait, std::tuple<Ts...>>::type>;
+};
+
+template <template <typename...> class Trait, typename T>
+struct apply_optional_trait {
+    using type =
+        std::tuple<typename optional_trait<typename Trait<T>::type, T>::type>;
+};
+
+template <template <typename...> class Trait, typename T>
+struct apply_optional_trait<Trait, std::tuple<T>> {
+    using type =
+        std::tuple<typename optional_trait<typename Trait<T>::type, T>::type>;
+};
+
+template <template <typename...> class Trait, typename... Ts>
+using apply_trait_optional_t = apply_optional_trait<Trait, Ts...>;
+
+////////////////
+// filter false_type
+////////////////
+
+template <typename T, typename... Ts>
+struct remove_false {
+    using type = tup_cat_t<T, typename remove_false<Ts...>::type>;
+};
+
+template <typename... Ts>
+struct remove_false<std::false_type, Ts...> {
+    using type = typename remove_false<Ts...>::type;
+};
+
+template <typename T, typename... Ts>
+struct remove_false<std::tuple<T, Ts...>> {
+    using type = tup_cat_t<T, typename remove_false<Ts...>::type>;
+};
+
+template <typename... Ts>
+struct remove_false<std::tuple<std::false_type, Ts...>> {
+    using type = typename remove_false<Ts...>::type;
+};
+
+template <typename T>
+struct remove_false<T> {
+    using type = std::tuple<T>;
+};
+
+template <typename T>
+struct remove_false<std::tuple<T>> {
+    using type = std::tuple<T>;
+};
+
+template <>
+struct remove_false<std::false_type> {
+    using type = std::tuple<>;
+};
+
+////////////////
+// negate trait
+////////////////
+
+template <template <typename...> class Trait>
+struct negate_impl {
+    template <typename... Ts>
+    using type = std::integral_constant<bool, !Trait<Ts...>::value>;
+};
+
+template <template <typename...> class Trait>
+using negate_impl_t = typename negate_impl<Trait>::type;
+
+////////////////
+// filter by trait
+////////////////
+
+template <template <typename...> class Trait, typename... Ts>
+struct filter_if {
+    using type = typename filter_if<Trait, std::tuple<Ts...>>::type;
+};
+
+template <template <typename...> class Trait, typename... Ts>
+struct filter_if<Trait, std::tuple<Ts...>> {
+
+    using type = typename remove_false<
+        typename apply_optional_trait<Trait, std::tuple<Ts...>>::type>::type;
+};
+
+template <template <typename...> class Trait, typename... Ts>
+using filter_if_t = typename filter_if<Trait, Ts...>::type;
+
+template <template <typename...> class Trait, typename... Ts>
+struct filter_not {
+    using type = typename filter_not<Trait, std::tuple<Ts...>>::type;
+};
+
+template <template <typename...> class Trait, typename... Ts>
+struct filter_not<Trait, std::tuple<Ts...>> {
+
+    using type = typename remove_false<typename apply_optional_trait<
+        negate_impl<Trait>::template type, std::tuple<Ts...>>::type>::type;
+};
+
+template <template <typename...> class Trait, typename... Ts>
+using filter_not_t = typename filter_not<Trait, Ts...>::type;
+
+////////////////
+// count
+////////////////
+
+template <template <typename...> class Trait, typename... Ts>
+struct count;
+
+template <template <typename...> class Trait, typename T, typename... Ts>
+struct count<Trait, T, Ts...> {
+    static constexpr size_t value =
+        std::tuple_size<filter_if_t<Trait, T, Ts...>>::value;
+};
+
+template <template <typename...> class Trait, typename T>
+struct count<Trait, T> {
+    static constexpr size_t value = Trait<T>::value;
+};
+
+template <template <typename...> class Trait>
+struct count<Trait> {
+    static constexpr size_t value = 0;
+};
+
+template <template <typename...> class Trait, typename... Ts>
+constexpr size_t count_v = count<Trait, Ts...>::value;
+
+////////////////
+// count not
+////////////////
+
+template <template <typename...> class Trait, typename... Ts>
+struct count_not;
+
+template <template <typename...> class Trait, typename T, typename... Ts>
+struct count_not<Trait, T, Ts...> {
+    static constexpr size_t value =
+        std::tuple_size<filter_not_t<Trait, T, Ts...>>::value;
+};
+
+template <template <typename...> class Trait, typename T>
+struct count_not<Trait, T> {
+    static constexpr size_t value = !Trait<T>::value;
+};
+
+template <template <typename...> class Trait>
+struct count_not<Trait> {
+    static constexpr size_t value = 0;
+};
+
+template <template <typename...> class Trait, typename... Ts>
+constexpr size_t count_not_v = count_not<Trait, Ts...>::value;
+
+////////////////
+// all of
+////////////////
+
+template <template <typename...> class Trait, typename... Ts>
+struct all_of {
+    static constexpr bool value = count_v<Trait, Ts...> == sizeof...(Ts);
+};
+
+template <template <typename...> class Trait, typename... Ts>
+struct all_of<Trait, std::tuple<Ts...>> {
+    static constexpr bool value = count_v<Trait, Ts...> == sizeof...(Ts);
+};
+
+template <template <typename...> class Trait, typename... Ts>
+constexpr bool all_of_v = all_of<Trait, Ts...>::value;
+
+////////////////
+// any of
+////////////////
+
+template <template <typename...> class Trait, typename... Ts>
+struct any_of {
+    static_assert(sizeof...(Ts) > 0);
+    static constexpr bool value = count_v<Trait, Ts...> > 0;
+};
+
+template <template <typename...> class Trait, typename... Ts>
+struct any_of<Trait, std::tuple<Ts...>> {
+    static_assert(sizeof...(Ts) > 0);
+    static constexpr bool value = count_v<Trait, Ts...> > 0;
+};
+
+template <template <typename...> class Trait, typename... Ts>
+constexpr bool any_of_v = any_of<Trait, Ts...>::value;
+
+////////////////
+// none  of
+////////////////
+
+template <template <typename...> class Trait, typename... Ts>
+struct none_of {
+    static constexpr bool value = count_v<Trait, Ts...> == 0;
+};
+
+template <template <typename...> class Trait, typename... Ts>
+struct none_of<Trait, std::tuple<Ts...>> {
+    static constexpr bool value = count_v<Trait, Ts...> == 0;
+};
+
+template <template <typename...> class Trait, typename... Ts>
+constexpr bool none_of_v = none_of<Trait, Ts...>::value;
+
+////////////////
+// is instance of
+////////////////
+
+template <template <typename...> class Template, typename T>
+struct is_instance_of {
+    constexpr static bool value = false;
+};
+
+template <template <typename...> class Template, typename... Ts>
+struct is_instance_of<Template, Template<Ts...>> {
+    constexpr static bool value = true;
+};
+
+template <template <typename...> class Template, typename... Ts>
+constexpr bool is_instance_of_v = is_instance_of<Template, Ts...>::value;
+
+////////////////
+// ternary
+////////////////
+
+template <bool B, typename T, typename U>
+struct ternary;
+
+template <typename T, typename U>
+struct ternary<true, T, U> {
+    using type = T;
+};
+
+template <typename T, typename U>
+struct ternary<false, T, U> {
+    using type = U;
+};
+
+template <bool B, typename T, typename U>
+using ternary_t = typename ternary<B, T, U>::type;
+
+////////////////
+// tuple to struct
+////////////////
+
+template <class T, std::size_t... Is, class U>
+T to_object_impl(std::index_sequence<Is...>, U&& data) {
+    return {std::get<Is>(std::forward<U>(data))...};
+}
+
+template <class T, class U>
+T to_object(U&& data) {
+    using NoRefU = std::decay_t<U>;
+    if constexpr (is_instance_of_v<std::tuple, NoRefU>) {
+        return to_object_impl<
+            T>(std::make_index_sequence<std::tuple_size<NoRefU>{}>{},
+               std::forward<U>(data));
+    } else {
+        return T{std::forward<U>(data)};
+    }
+}
+
+} /* trait */
+
+
+namespace ss {
+
+////////////////
+// function traits
+////////////////
+
+template <size_t N, typename T, typename... Ts>
+struct decayed_arg_n {
+    static_assert(N - 1 != sizeof...(Ts), "index out of range");
+    using type = typename decayed_arg_n<N - 1, Ts...>::type;
+};
+
+template <typename T, typename... Ts>
+struct decayed_arg_n<0, T, Ts...> {
+    using type = std::decay_t<T>;
+};
+
+template <typename T>
+struct function_traits;
+
+template <typename R, typename C, typename Arg>
+struct function_traits<std::function<R(C&, const Arg&) const>> {
+    using arg_type = Arg;
+};
+
+template <typename R, typename... Ts>
+struct function_traits<R(Ts...)> {
+    using arg0 = typename decayed_arg_n<0, Ts...>::type;
+};
+
+template <typename R, typename... Ts>
+struct function_traits<R(Ts...) const> : function_traits<R(Ts...)> {};
+
+template <typename R, typename... Ts>
+struct function_traits<R(Ts...)&> : function_traits<R(Ts...)> {};
+
+template <typename R, typename... Ts>
+struct function_traits<R(Ts...) const&> : function_traits<R(Ts...)> {};
+
+template <typename R, typename... Ts>
+struct function_traits<R(Ts...) &&> : function_traits<R(Ts...)> {};
+
+template <typename R, typename... Ts>
+struct function_traits<R(Ts...) const&&> : function_traits<R(Ts...)> {};
+
+template <typename MemberFunction>
+struct member_wrapper;
+
+template <typename R, typename T>
+struct member_wrapper<R T::*> {
+    using arg_type = typename function_traits<R>::arg0;
+};
+
+////////////////
+// has method
+////////////////
+
+#define INIT_HAS_METHOD(method)                                                \
+    template <typename T>                                                      \
+    class has_m_##method {                                                     \
+        template <typename C>                                                  \
+        static std::true_type test(decltype(&C::method));                      \
+                                                                               \
+        template <typename C>                                                  \
+        static std::false_type test(...);                                      \
+                                                                               \
+    public:                                                                    \
+        constexpr static bool value = decltype(test<T>(0))::value;             \
+    };                                                                         \
+                                                                               \
+    template <typename T>                                                      \
+    constexpr bool has_m_##method##_t = has_m_##method<T>::value;
+
+} /* trait */
+
+namespace ss {
+
+////////////////
+// all except
+////////////////
+
+template <typename T, auto... Values>
+struct ax {
+private:
+    template <auto X, auto... Xs>
+    bool ss_valid_impl(const T& x) const {
+        if constexpr (sizeof...(Xs) != 0) {
+            return x != X && ss_valid_impl<Xs...>(x);
+        }
+        return x != X;
+    }
+
+public:
+    bool ss_valid(const T& value) const {
+        return ss_valid_impl<Values...>(value);
+    }
+
+    const char* error() const {
+        return "value excluded";
+    }
+};
+
+////////////////
+// none except
+////////////////
+
+template <typename T, auto... Values>
+struct nx {
+private:
+    template <auto X, auto... Xs>
+    bool ss_valid_impl(const T& x) const {
+        if constexpr (sizeof...(Xs) != 0) {
+            return x == X || ss_valid_impl<Xs...>(x);
+        }
+        return x == X;
+    }
+
+public:
+    bool ss_valid(const T& value) const {
+        return ss_valid_impl<Values...>(value);
+    }
+
+    const char* error() const {
+        return "value excluded";
+    }
+};
+
+////////////////
+// greater than or equal to
+// greater than
+// less than
+// less than or equal to
+////////////////
+
+template <typename T, auto N>
+struct gt {
+    bool ss_valid(const T& value) const {
+        return value > N;
+    }
+};
+
+template <typename T, auto N>
+struct gte {
+    bool ss_valid(const T& value) const {
+        return value >= N;
+    }
+};
+
+template <typename T, auto N>
+struct lt {
+    bool ss_valid(const T& value) const {
+        return value < N;
+    }
+};
+
+template <typename T, auto N>
+struct lte {
+    bool ss_valid(const T& value) const {
+        return value <= N;
+    }
+};
+
+////////////////
+// in range
+////////////////
+
+template <typename T, auto Min, auto Max>
+struct ir {
+    bool ss_valid(const T& value) const {
+        return value >= Min && value <= Max;
+    }
+};
+
+////////////////
+// out of range
+////////////////
+
+template <typename T, auto Min, auto Max>
+struct oor {
+    bool ss_valid(const T& value) const {
+        return value < Min || value > Max;
+    }
+};
+
+////////////////
+// non empty
+////////////////
+
+template <typename T>
+struct ne {
+    bool ss_valid(const T& value) const {
+        return !value.empty();
+    }
+
+    const char* error() const {
+        return "empty field";
+    }
+};
+
+} /* ss */
+
+namespace ss {
+
+struct none {};
+
+using string_range = std::pair<const char*, const char*>;
+using split_data = std::vector<string_range>;
+
+constexpr inline auto default_delimiter = ",";
+
+template <bool StringError>
+inline void assert_string_error_defined() {
+    static_assert(StringError,
+                  "'string_error' needs to be enabled to use 'error_msg'");
+}
+
+#if __unix__
+inline ssize_t get_line(char** lineptr, size_t* n, FILE* stream) {
+    return getline(lineptr, n, stream);
+}
+#else
+using ssize_t = int64_t;
+inline ssize_t get_line(char** lineptr, size_t* n, FILE* stream) {
+    size_t pos;
+    int c;
+
+    if (lineptr == nullptr || stream == nullptr || n == nullptr) {
+        errno = EINVAL;
+        return -1;
+    }
+
+    c = getc(stream);
+    if (c == EOF) {
+        return -1;
+    }
+
+    if (*lineptr == nullptr) {
+        *lineptr = static_cast<char*>(malloc(128));
+        if (*lineptr == nullptr) {
+            return -1;
+        }
+        *n = 128;
+    }
+
+    pos = 0;
+    while (c != EOF) {
+        if (pos + 1 >= *n) {
+            size_t new_size = *n + (*n >> 2);
+            if (new_size < 128) {
+                new_size = 128;
+            }
+            char* new_ptr = static_cast<char*>(
+                realloc(static_cast<void*>(*lineptr), new_size));
+            if (new_ptr == nullptr) {
+                return -1;
+            }
+            *n = new_size;
+            *lineptr = new_ptr;
+        }
+
+        (*lineptr)[pos++] = c;
+        if (c == '\n') {
+            break;
+        }
+        c = getc(stream);
+    }
+
+    (*lineptr)[pos] = '\0';
+    return pos;
+}
+#endif
+
+} /* ss */
+
+namespace ss {
+
+////////////////
+// matcher
+////////////////
+
+template <char... Cs>
+struct matcher {
+private:
+    template <char X, char... Xs>
+    static bool match_impl(char c) {
+        if constexpr (sizeof...(Xs) != 0) {
+            return (c == X) || match_impl<Xs...>(c);
+        }
+        return (c == X);
+    }
+
+    constexpr static bool contains_string_terminator() {
+        for (const auto& match : matches) {
+            if (match == '\0') {
+                return false;
+            }
+        }
+        return true;
+    }
+
+public:
+    static bool match(char c) {
+        return match_impl<Cs...>(c);
+    }
+
+    constexpr static bool enabled = true;
+    constexpr static std::array<char, sizeof...(Cs)> matches{Cs...};
+    static_assert(contains_string_terminator(),
+                  "string terminator cannot be used as a match character");
+};
+
+template <typename FirstMatcher, typename SecondMatcher>
+inline constexpr bool matches_intersect() {
+    for (const auto& first_match : FirstMatcher::matches) {
+        for (const auto& second_match : SecondMatcher::matches) {
+            if (first_match != '\0' && first_match == second_match) {
+                return true;
+            }
+        }
+    }
+    return false;
+}
+
+template <typename FirstMatcher, typename SecondMatcher1,
+          typename SecondMatcher2>
+inline constexpr bool matches_intersect_union() {
+    return matches_intersect<FirstMatcher, SecondMatcher1>() ||
+           matches_intersect<FirstMatcher, SecondMatcher2>();
+}
+
+template <>
+class matcher<'\0'> {
+public:
+    constexpr static bool enabled = false;
+    constexpr static std::array<char, 1> matches{'\0'};
+    static bool match(char c) = delete;
+};
+
+////////////////
+// setup
+////////////////
+
+////////////////
+// matcher
+////////////////
+
+template <char C>
+struct quote : matcher<C> {};
+
+template <char... Cs>
+struct trim : matcher<Cs...> {};
+
+template <char... Cs>
+struct trim_left : matcher<Cs...> {};
+
+template <char... Cs>
+struct trim_right : matcher<Cs...> {};
+
+template <char... Cs>
+struct escape : matcher<Cs...> {};
+
+template <typename T, template <char...> class Template>
+struct is_instance_of_matcher : std::false_type {};
+
+template <char... Ts, template <char...> class Template>
+struct is_instance_of_matcher<Template<Ts...>, Template> : std::true_type {};
+
+template <typename T, template <char...> class Template>
+using is_instance_of_matcher_t =
+    typename is_instance_of_matcher<T, Template>::type;
+
+template <template <char...> class Matcher, typename... Ts>
+struct get_matcher;
+
+template <template <char...> class Matcher, typename T, typename... Ts>
+struct get_matcher<Matcher, T, Ts...> {
+
+    template <typename U>
+    struct is_matcher : is_instance_of_matcher<U, Matcher> {};
+
+    static_assert(count_v<is_matcher, T, Ts...> <= 1,
+                  "the same matcher is cannot"
+                  "be defined multiple times");
+    using type = ternary_t<is_matcher<T>::value, T,
+                           typename get_matcher<Matcher, Ts...>::type>;
+};
+
+template <template <char...> class Matcher>
+struct get_matcher<Matcher> {
+    using type = Matcher<'\0'>;
+};
+
+template <template <char...> class Matcher, typename... Ts>
+using get_matcher_t = typename get_matcher<Matcher, Ts...>::type;
+
+////////////////
+// multiline
+////////////////
+
+template <size_t S, bool B = true>
+struct multiline_restricted {
+    constexpr static auto size = S;
+    constexpr static auto enabled = B;
+};
+
+using multiline = multiline_restricted<0>;
+
+template <typename T>
+struct is_instance_of_multiline : std::false_type {};
+
+template <size_t S, bool B>
+struct is_instance_of_multiline<multiline_restricted<S, B>> : std::true_type {};
+
+template <typename T>
+using is_instance_of_multiline_t = typename is_instance_of_multiline<T>::type;
+
+template <typename... Ts>
+struct get_multiline;
+
+template <typename T, typename... Ts>
+struct get_multiline<T, Ts...> {
+    using type = ternary_t<is_instance_of_multiline<T>::value, T,
+                           typename get_multiline<Ts...>::type>;
+};
+
+template <>
+struct get_multiline<> {
+    using type = multiline_restricted<0, false>;
+};
+
+template <typename... Ts>
+using get_multiline_t = typename get_multiline<Ts...>::type;
+
+////////////////
+// string_error
+////////////////
+
+class string_error;
+
+////////////////
+// ignore_header
+////////////////
+
+class ignore_header;
+
+////////////////
+// ignore_empty
+////////////////
+
+class ignore_empty;
+
+////////////////
+// setup implementation
+////////////////
+
+template <typename... Ts>
+struct setup {
+private:
+    template <typename T>
+    struct is_matcher
+        : std::disjunction<is_instance_of_matcher_t<T, quote>,
+                           is_instance_of_matcher_t<T, escape>,
+                           is_instance_of_matcher_t<T, trim>,
+                           is_instance_of_matcher_t<T, trim_left>,
+                           is_instance_of_matcher_t<T, trim_right>> {};
+
+    template <typename T>
+    struct is_string_error : std::is_same<T, string_error> {};
+
+    template <typename T>
+    struct is_ignore_header : std::is_same<T, ignore_header> {};
+
+    template <typename T>
+    struct is_ignore_empty : std::is_same<T, ignore_empty> {};
+
+    constexpr static auto count_matcher = count_v<is_matcher, Ts...>;
+
+    constexpr static auto count_multiline =
+        count_v<is_instance_of_multiline, Ts...>;
+
+    constexpr static auto count_string_error = count_v<is_string_error, Ts...>;
+
+    constexpr static auto count_ignore_header =
+        count_v<is_ignore_header, Ts...>;
+
+    constexpr static auto count_ignore_empty = count_v<is_ignore_empty, Ts...>;
+
+    constexpr static auto number_of_valid_setup_types =
+        count_matcher + count_multiline + count_string_error +
+        count_ignore_header + count_ignore_empty;
+
+    using trim_left_only = get_matcher_t<trim_left, Ts...>;
+    using trim_right_only = get_matcher_t<trim_right, Ts...>;
+    using trim_all = get_matcher_t<trim, Ts...>;
+
+public:
+    using quote = get_matcher_t<quote, Ts...>;
+    using escape = get_matcher_t<escape, Ts...>;
+
+    using trim_left = ternary_t<trim_all::enabled, trim_all, trim_left_only>;
+    using trim_right = ternary_t<trim_all::enabled, trim_all, trim_right_only>;
+
+    using multiline = get_multiline_t<Ts...>;
+    constexpr static bool string_error = (count_string_error == 1);
+    constexpr static bool ignore_header = (count_ignore_header == 1);
+    constexpr static bool ignore_empty = (count_ignore_empty == 1);
+
+private:
+#define ASSERT_MSG "cannot have the same match character in multiple matchers"
+    static_assert(!matches_intersect<escape, quote>(), ASSERT_MSG);
+
+    constexpr static auto quote_trim_intersect =
+        matches_intersect_union<quote, trim_left, trim_right>();
+    static_assert(!quote_trim_intersect, ASSERT_MSG);
+
+    constexpr static auto escape_trim_intersect =
+        matches_intersect_union<escape, trim_left, trim_right>();
+    static_assert(!escape_trim_intersect, ASSERT_MSG);
+
+#undef ASSERT_MSG
+
+    static_assert(
+        !multiline::enabled ||
+            (multiline::enabled && (quote::enabled || escape::enabled)),
+        "to enable multiline either quote or escape need to be enabled");
+
+    static_assert(!(trim_all::enabled && trim_left_only::enabled) &&
+                      !(trim_all::enabled && trim_right_only::enabled),
+                  "ambiguous trim setup");
+
+    static_assert(count_multiline <= 1, "mutliline defined multiple times");
+    static_assert(count_string_error <= 1,
+                  "string_error defined multiple times");
+
+    static_assert(number_of_valid_setup_types == sizeof...(Ts),
+                  "one or multiple invalid setup parameters defined");
+};
+
+template <typename... Ts>
+struct setup<setup<Ts...>> : setup<Ts...> {};
+
+} /* ss */
+
+namespace ss {
+
+template <typename... Ts>
+class splitter {
+private:
+    using quote = typename setup<Ts...>::quote;
+    using trim_left = typename setup<Ts...>::trim_left;
+    using trim_right = typename setup<Ts...>::trim_right;
+    using escape = typename setup<Ts...>::escape;
+    using multiline = typename setup<Ts...>::multiline;
+
+    constexpr static auto string_error = setup<Ts...>::string_error;
+    constexpr static auto is_const_line = !quote::enabled && !escape::enabled;
+
+    using error_type = ss::ternary_t<string_error, std::string, bool>;
+
+public:
+    using line_ptr_type = ternary_t<is_const_line, const char*, char*>;
+
+    bool valid() const {
+        if constexpr (string_error) {
+            return error_.empty();
+        } else {
+            return !error_;
+        }
+    }
+
+    const std::string& error_msg() const {
+        assert_string_error_defined<string_error>();
+        return error_;
+    }
+
+    bool unterminated_quote() const {
+        return unterminated_quote_;
+    }
+
+    const split_data& split(line_ptr_type new_line,
+                            const std::string& delimiter = default_delimiter) {
+        split_data_.clear();
+        line_ = new_line;
+        begin_ = line_;
+        return split_impl_select_delim(delimiter);
+    }
+
+private:
+    ////////////////
+    // resplit
+    ////////////////
+
+    // number of characters the end of line is shifted backwards
+    size_t size_shifted() const {
+        return escaped_;
+    }
+
+    void adjust_ranges(const char* old_line) {
+        for (auto& [begin, end] : split_data_) {
+            begin = begin - old_line + line_;
+            end = end - old_line + line_;
+        }
+    }
+
+    const split_data& resplit(
+        line_ptr_type new_line, ssize_t new_size,
+        const std::string& delimiter = default_delimiter) {
+
+        // resplitting, continue from last slice
+        if (!quote::enabled || !multiline::enabled || split_data_.empty() ||
+            !unterminated_quote()) {
+            set_error_invalid_resplit();
+            return split_data_;
+        }
+
+        const auto [old_line, old_begin] = *std::prev(split_data_.end());
+        size_t begin = old_begin - old_line - 1;
+
+        // safety measure
+        if (new_size != -1 && static_cast<size_t>(new_size) < begin) {
+            set_error_invalid_resplit();
+            return split_data_;
+        }
+
+        // if unterminated quote, the last element is junk
+        split_data_.pop_back();
+
+        line_ = new_line;
+        adjust_ranges(old_line);
+
+        begin_ = line_ + begin;
+        end_ = line_ - old_line + end_ - escaped_;
+        curr_ = end_;
+
+        resplitting_ = true;
+
+        return split_impl_select_delim(delimiter);
+    }
+
+    ////////////////
+    // error
+    ////////////////
+
+    void clear_error() {
+        if constexpr (string_error) {
+            error_.clear();
+        } else {
+            error_ = false;
+        }
+        unterminated_quote_ = false;
+    }
+
+    void set_error_empty_delimiter() {
+        if constexpr (string_error) {
+            error_.clear();
+            error_.append("empt  delimiter");
+        } else {
+            error_ = true;
+        }
+    }
+
+    void set_error_mismatched_quote(size_t n) {
+        if constexpr (string_error) {
+            error_.clear();
+            error_.append("mismatched quote at position: " + std::to_string(n));
+        } else {
+            error_ = true;
+        }
+    }
+
+    void set_error_unterminated_escape() {
+        if constexpr (string_error) {
+            error_.clear();
+            error_.append("unterminated escape at the end of the line");
+        } else {
+            error_ = true;
+        }
+    }
+
+    void set_error_unterminated_quote() {
+        unterminated_quote_ = true;
+        if constexpr (string_error) {
+            error_.clear();
+            error_.append("unterminated quote");
+        } else {
+            error_ = true;
+        }
+    }
+
+    void set_error_invalid_resplit() {
+        unterminated_quote_ = false;
+        if constexpr (string_error) {
+            error_.clear();
+            error_.append("invalid resplit, new line must be longer"
+                          "than the end of the last slice");
+        } else {
+            error_ = true;
+        }
+    }
+
+    ////////////////
+    // matching
+    ////////////////
+
+    bool match(const char* const curr, char delim) {
+        return *curr == delim;
+    };
+
+    bool match(const char* const curr, const std::string& delim) {
+        return strncmp(curr, delim.c_str(), delim.size()) == 0;
+    };
+
+    size_t delimiter_size(char) {
+        return 1;
+    }
+
+    size_t delimiter_size(const std::string& delim) {
+        return delim.size();
+    }
+
+    void trim_left_if_enabled(line_ptr_type& curr) {
+        if constexpr (trim_left::enabled) {
+            while (trim_left::match(*curr)) {
+                ++curr;
+            }
+        }
+    }
+
+    void trim_right_if_enabled(line_ptr_type& curr) {
+        if constexpr (trim_right::enabled) {
+            while (trim_right::match(*curr)) {
+                ++curr;
+            }
+        }
+    }
+
+    template <typename Delim>
+    std::tuple<size_t, bool> match_delimiter(line_ptr_type begin,
+                                             const Delim& delim) {
+        line_ptr_type end = begin;
+
+        trim_right_if_enabled(end);
+
+        // just spacing
+        if (*end == '\0') {
+            return {0, false};
+        }
+
+        // not a delimiter
+        if (!match(end, delim)) {
+            shift_if_escaped(end);
+            return {1 + end - begin, false};
+        }
+
+        end += delimiter_size(delim);
+        trim_left_if_enabled(end);
+
+        // delimiter
+        return {end - begin, true};
+    }
+
+    ////////////////
+    // shifting
+    ////////////////
+
+    void shift_if_escaped(line_ptr_type& curr) {
+        if constexpr (escape::enabled) {
+            if (escape::match(*curr)) {
+                if (curr[1] == '\0') {
+                    set_error_unterminated_escape();
+                    done_ = true;
+                    return;
+                }
+                shift_and_jump_escape();
+            }
+        }
+    }
+
+    void shift_and_jump_escape() {
+        shift_and_set_current();
+        if constexpr (!is_const_line) {
+            ++escaped_;
+        }
+        ++end_;
+    }
+
+    void shift_push_and_start_next(size_t n) {
+        shift_and_push();
+        begin_ = end_ + n;
+    }
+
+    void shift_and_push() {
+        shift_and_set_current();
+        split_data_.emplace_back(begin_, curr_);
+    }
+
+    void shift_and_set_current() {
+        if constexpr (!is_const_line) {
+            if (escaped_ > 0) {
+                std::copy_n(curr_ + escaped_, end_ - curr_ - escaped_, curr_);
+                curr_ = end_ - escaped_;
+                return;
+            }
+        }
+        curr_ = end_;
+    }
+
+    ////////////////
+    // split impl
+    ////////////////
+
+    const split_data& split_impl_select_delim(
+        const std::string& delimiter = default_delimiter) {
+        clear_error();
+        switch (delimiter.size()) {
+        case 0:
+            set_error_empty_delimiter();
+            return split_data_;
+        case 1:
+            return split_impl(delimiter[0]);
+        default:
+            return split_impl(delimiter);
+        }
+    }
+
+    template <typename Delim>
+    const split_data& split_impl(const Delim& delim) {
+
+        trim_left_if_enabled(begin_);
+
+        for (done_ = false; !done_; read(delim))
+            ;
+
+        return split_data_;
+    }
+
+    ////////////////
+    // reading
+    ////////////////
+
+    template <typename Delim>
+    void read(const Delim& delim) {
+        escaped_ = 0;
+        if constexpr (quote::enabled) {
+            if constexpr (multiline::enabled) {
+                if (resplitting_) {
+                    resplitting_ = false;
+                    ++begin_;
+                    read_quoted(delim);
+                    return;
+                }
+            }
+            if (quote::match(*begin_)) {
+                curr_ = end_ = ++begin_;
+                read_quoted(delim);
+                return;
+            }
+        }
+        curr_ = end_ = begin_;
+        read_normal(delim);
+    }
+
+    template <typename Delim>
+    void read_normal(const Delim& delim) {
+        while (true) {
+            auto [width, valid] = match_delimiter(end_, delim);
+
+            if (!valid) {
+                // not a delimiter
+                if (width == 0) {
+                    // eol
+                    shift_and_push();
+                    done_ = true;
+                    break;
+                } else {
+                    end_ += width;
+                    continue;
+                }
+            } else {
+                // found delimiter
+                shift_push_and_start_next(width);
+                break;
+            }
+        }
+    }
+
+    template <typename Delim>
+    void read_quoted(const Delim& delim) {
+        if constexpr (quote::enabled) {
+            while (true) {
+                if (!quote::match(*end_)) {
+                    if constexpr (escape::enabled) {
+                        if (escape::match(*end_)) {
+                            if (end_[1] == '\0') {
+                                // eol, unterminated escape
+                                // eg: ... "hel\\0
+                                set_error_unterminated_escape();
+                                done_ = true;
+                                break;
+                            }
+                            // not eol
+
+                            shift_and_jump_escape();
+                            ++end_;
+                            continue;
+                        }
+                    }
+                    // not escaped
+
+                    // eol, unterminated quote error
+                    // eg: ..."hell\0 -> quote not terminated
+                    if (*end_ == '\0') {
+                        shift_and_set_current();
+                        set_error_unterminated_quote();
+                        split_data_.emplace_back(line_, begin_);
+                        done_ = true;
+                        break;
+                    }
+                    // not eol
+
+                    ++end_;
+                    continue;
+                }
+                // quote found
+                // ...
+
+                auto [width, valid] = match_delimiter(end_ + 1, delim);
+
+                // delimiter
+                if (valid) {
+                    shift_push_and_start_next(width + 1);
+                    break;
+                }
+                // not delimiter
+
+                // double quote
+                // eg: ...,"hel""lo",... -> hel"lo
+                if (quote::match(end_[1])) {
+                    shift_and_jump_escape();
+                    ++end_;
+                    continue;
+                }
+                // not double quote
+
+                if (width == 0) {
+                    // eol
+                    // eg: ...,"hello"   \0 -> hello
+                    // eg no trim: ...,"hello"\0 -> hello
+                    shift_and_push();
+                } else {
+                    // mismatched quote
+                    // eg: ...,"hel"lo,... -> error
+                    set_error_mismatched_quote(end_ - line_);
+                    split_data_.emplace_back(line_, begin_);
+                }
+                done_ = true;
+                break;
+            }
+        }
+    }
+
+    ////////////////
+    // members
+    ////////////////
+
+public:
+    error_type error_{};
+    bool unterminated_quote_{false};
+    bool done_{true};
+    bool resplitting_{false};
+    size_t escaped_{0};
+    split_data split_data_;
+
+    line_ptr_type begin_;
+    line_ptr_type curr_;
+    line_ptr_type end_;
+    line_ptr_type line_;
+
+    template <typename...>
+    friend class converter;
+};
+
+} /* ss */
+
+
+#ifndef SSP_DISABLE_FAST_FLOAT
+#else
+#endif
+
+namespace ss {
+
+////////////////
+// number converters
+////////////////
+
+#ifndef SSP_DISABLE_FAST_FLOAT
+
+template <typename T>
+std::enable_if_t<std::is_floating_point_v<T>, std::optional<T>> to_num(
+    const char* const begin, const char* const end) {
+    T ret;
+    auto [ptr, ec] = fast_float::from_chars(begin, end, ret);
+
+    if (ec != std::errc() || ptr != end) {
+        return std::nullopt;
+    }
+    return ret;
+}
+
+#else
+
+template <typename T>
+std::enable_if_t<std::is_floating_point_v<T>, std::optional<T>> to_num(
+    const char* const begin, const char* const end) {
+    T ret;
+    auto [ptr, ec] = std::from_chars(begin, end, ret);
+
+    if (ec != std::errc() || ptr != end) {
+        return std::nullopt;
+    }
+    return ret;
+}
+
+#endif
+
+inline std::optional<short> from_char(char c) {
+    if (c >= '0' && c <= '9') {
+        return c - '0';
+    }
+    return std::nullopt;
+}
+
+#if defined(__clang__) && defined(__MINGW32__) && !defined(__MINGW64__)
+#define MINGW32_CLANG
+#endif
+
+// mingw32 clang does not support some of the builtin functions
+#if (defined(__clang__) || defined(__GNUC__) || defined(__GUNG__)) &&          \
+    !defined(MINGW32_CLANG)
+////////////////
+// mul overflow detection
+////////////////
+template <typename T>
+bool mul_overflow(T& result, T operand) {
+    return __builtin_mul_overflow(result, operand, &result);
+}
+
+template <>
+inline bool mul_overflow(int& result, int operand) {
+    return __builtin_smul_overflow(result, operand, &result);
+}
+
+template <>
+inline bool mul_overflow(long& result, long operand) {
+    return __builtin_smull_overflow(result, operand, &result);
+}
+
+template <>
+inline bool mul_overflow(long long& result, long long operand) {
+    return __builtin_smulll_overflow(result, operand, &result);
+}
+
+template <>
+inline bool mul_overflow(unsigned int& result, unsigned int operand) {
+    return __builtin_umul_overflow(result, operand, &result);
+}
+
+template <>
+inline bool mul_overflow(unsigned long& result, unsigned long operand) {
+    return __builtin_umull_overflow(result, operand, &result);
+}
+
+template <>
+inline bool mul_overflow(unsigned long long& result,
+                         unsigned long long operand) {
+    return __builtin_umulll_overflow(result, operand, &result);
+}
+
+////////////////
+// addition overflow detection
+////////////////
+
+template <typename T>
+inline bool add_overflow(T& result, T operand) {
+    return __builtin_add_overflow(result, operand, &result);
+}
+
+template <>
+inline bool add_overflow(int& result, int operand) {
+    return __builtin_sadd_overflow(result, operand, &result);
+}
+
+template <>
+inline bool add_overflow(long& result, long operand) {
+    return __builtin_saddl_overflow(result, operand, &result);
+}
+
+template <>
+inline bool add_overflow(long long& result, long long operand) {
+    return __builtin_saddll_overflow(result, operand, &result);
+}
+
+template <>
+inline bool add_overflow(unsigned int& result, unsigned int operand) {
+    return __builtin_uadd_overflow(result, operand, &result);
+}
+
+template <>
+inline bool add_overflow(unsigned long& result, unsigned long operand) {
+    return __builtin_uaddl_overflow(result, operand, &result);
+}
+
+template <>
+inline bool add_overflow(unsigned long long& result,
+                         unsigned long long operand) {
+    return __builtin_uaddll_overflow(result, operand, &result);
+}
+
+////////////////
+// substraction overflow detection
+////////////////
+template <typename T>
+inline bool sub_overflow(T& result, T operand) {
+    return __builtin_sub_overflow(result, operand, &result);
+}
+
+template <>
+inline bool sub_overflow(int& result, int operand) {
+    return __builtin_ssub_overflow(result, operand, &result);
+}
+
+template <>
+inline bool sub_overflow(long& result, long operand) {
+    return __builtin_ssubl_overflow(result, operand, &result);
+}
+
+template <>
+inline bool sub_overflow(long long& result, long long operand) {
+    return __builtin_ssubll_overflow(result, operand, &result);
+}
+
+template <>
+inline bool sub_overflow(unsigned int& result, unsigned int operand) {
+    return __builtin_usub_overflow(result, operand, &result);
+}
+
+template <>
+inline bool sub_overflow(unsigned long& result, unsigned long operand) {
+    return __builtin_usubl_overflow(result, operand, &result);
+}
+
+template <>
+inline bool sub_overflow(unsigned long long& result,
+                         unsigned long long operand) {
+    return __builtin_usubll_overflow(result, operand, &result);
+}
+
+template <typename T, typename F>
+bool shift_and_add_overflow(T& value, T digit, F add_last_digit_owerflow) {
+    if (mul_overflow<T>(value, 10) || add_last_digit_owerflow(value, digit)) {
+        return true;
+    }
+    return false;
+}
+#else
+
+template <typename T, typename U>
+bool shift_and_add_overflow(T& value, T digit, U is_negative) {
+    digit = (is_negative) ? -digit : digit;
+    T old_value = value;
+    value = 10 * value + digit;
+
+    T expected_old_value = (value - digit) / 10;
+    if (old_value != expected_old_value) {
+        return true;
+    }
+    return false;
+}
+
+#endif
+
+template <typename T>
+std::enable_if_t<std::is_integral_v<T>, std::optional<T>> to_num(
+    const char* begin, const char* end) {
+    if (begin == end) {
+        return std::nullopt;
+    }
+    bool is_negative = false;
+    if constexpr (std::is_signed_v<T>) {
+        is_negative = *begin == '-';
+        if (is_negative) {
+            ++begin;
+        }
+    }
+
+#if (defined(__clang__) || defined(__GNUC__) || defined(__GUNG__)) &&          \
+    !defined(MINGW32_CLANG)
+    auto add_last_digit_owerflow =
+        (is_negative) ? sub_overflow<T> : add_overflow<T>;
+#else
+    auto add_last_digit_owerflow = is_negative;
+#endif
+
+    T value = 0;
+    for (auto i = begin; i != end; ++i) {
+        if (auto digit = from_char(*i);
+            !digit || shift_and_add_overflow<T>(value, digit.value(),
+                                                add_last_digit_owerflow)) {
+            return std::nullopt;
+        }
+    }
+
+    return value;
+}
+
+////////////////
+// extract
+////////////////
+
+namespace error {
+template <typename T>
+struct unsupported_type {
+    constexpr static bool value = false;
+};
+} /* namespace */
+
+template <typename T>
+std::enable_if_t<!std::is_integral_v<T> && !std::is_floating_point_v<T> &&
+                     !is_instance_of_v<std::optional, T> &&
+                     !is_instance_of_v<std::variant, T>,
+                 bool>
+extract(const char*, const char*, T&) {
+    static_assert(error::unsupported_type<T>::value,
+                  "Conversion for given type is not defined, an "
+                  "\'extract\' function needs to be defined!");
+}
+
+template <typename T>
+std::enable_if_t<std::is_integral_v<T> || std::is_floating_point_v<T>, bool>
+extract(const char* begin, const char* end, T& value) {
+    auto optional_value = to_num<T>(begin, end);
+    if (!optional_value) {
+        return false;
+    }
+    value = optional_value.value();
+    return true;
+}
+
+template <typename T>
+std::enable_if_t<is_instance_of_v<std::optional, T>, bool> extract(
+    const char* begin, const char* end, T& value) {
+    typename T::value_type raw_value;
+    if (extract(begin, end, raw_value)) {
+        value = raw_value;
+    } else {
+        value = std::nullopt;
+    }
+    return true;
+}
+
+template <typename T, size_t I>
+bool extract_variant(const char* begin, const char* end, T& value) {
+    using IthType = std::variant_alternative_t<I, std::decay_t<T>>;
+    IthType ithValue;
+    if (extract<IthType>(begin, end, ithValue)) {
+        value = ithValue;
+        return true;
+    } else if constexpr (I + 1 < std::variant_size_v<T>) {
+        return extract_variant<T, I + 1>(begin, end, value);
+    }
+    return false;
+}
+
+template <typename T>
+std::enable_if_t<is_instance_of_v<std::variant, T>, bool> extract(
+    const char* begin, const char* end, T& value) {
+    return extract_variant<T, 0>(begin, end, value);
+}
+
+////////////////
+// extract specialization
+////////////////
+
+template <>
+inline bool extract(const char* begin, const char* end, bool& value) {
+    if (end == begin + 1) {
+        if (*begin == '1') {
+            value = true;
+        } else if (*begin == '0') {
+            value = false;
+        } else {
+            return false;
+        }
+    } else {
+        size_t size = end - begin;
+        if (size == 4 && strncmp(begin, "true", size) == 0) {
+            value = true;
+        } else if (size == 5 && strncmp(begin, "false", size) == 0) {
+            value = false;
+        } else {
+            return false;
+        }
+    }
+
+    return true;
+}
+
+template <>
+inline bool extract(const char* begin, const char* end, char& value) {
+    value = *begin;
+    return (end == begin + 1);
+}
+
+template <>
+inline bool extract(const char* begin, const char* end, std::string& value) {
+    value = std::string{begin, end};
+    return true;
+}
+
+template <>
+inline bool extract(const char* begin, const char* end,
+                    std::string_view& value) {
+    value = std::string_view{begin, static_cast<size_t>(end - begin)};
+    return true;
+}
+
+} /* ss */
+
+namespace ss {
+INIT_HAS_METHOD(tied)
+INIT_HAS_METHOD(ss_valid)
+INIT_HAS_METHOD(error)
+
+////////////////
+// replace validator
+////////////////
+
+// replace 'validator' types with elements they operate on
+// eg. no_validator_tup_t<int, ss::nx<char, 'A', 'B'>> <=> std::tuple<int, char>
+// where ss::nx<char, 'A', 'B'> is a validator '(n)one e(x)cept' which
+// checks if the returned character is either 'A' or 'B', returns error if not
+// additionally if one element is left in the pack, it will be unwrapped from
+// the tuple eg. no_void_validator_tup_t<int> <=> int instead of std::tuple<int>
+template <typename T, typename U = void>
+struct no_validator;
+
+template <typename T>
+struct no_validator<T, typename std::enable_if_t<has_m_ss_valid_t<T>>> {
+    using type = typename member_wrapper<decltype(&T::ss_valid)>::arg_type;
+};
+
+template <typename T, typename U>
+struct no_validator {
+    using type = T;
+};
+
+template <typename T>
+using no_validator_t = typename no_validator<T>::type;
+
+template <typename... Ts>
+struct no_validator_tup : apply_trait<no_validator, std::tuple<Ts...>> {};
+
+template <typename... Ts>
+struct no_validator_tup<std::tuple<Ts...>> : no_validator_tup<Ts...> {};
+
+template <typename T>
+struct no_validator_tup<std::tuple<T>> : no_validator<T> {};
+
+template <typename... Ts>
+using no_validator_tup_t = typename no_validator_tup<Ts...>::type;
+
+////////////////
+// no void tuple
+////////////////
+
+template <typename... Ts>
+struct no_void_tup : filter_not<std::is_void, no_validator_tup_t<Ts...>> {};
+
+template <typename... Ts>
+using no_void_tup_t = filter_not_t<std::is_void, Ts...>;
+
+////////////////
+// no void or validator
+////////////////
+
+// replace 'validators' and remove void from tuple
+template <typename... Ts>
+struct no_void_validator_tup : no_validator_tup<no_void_tup_t<Ts...>> {};
+
+template <typename... Ts>
+struct no_void_validator_tup<std::tuple<Ts...>>
+    : no_validator_tup<no_void_tup_t<Ts...>> {};
+
+template <typename... Ts>
+using no_void_validator_tup_t = typename no_void_validator_tup<Ts...>::type;
+
+////////////////
+// tied class
+////////////////
+
+// check if the parameter pack is only one element which is a class and has
+// the 'tied' method which is to be used for type deduction when converting
+template <typename T, typename... Ts>
+struct tied_class {
+    constexpr static bool value =
+        (sizeof...(Ts) == 0 && std::is_class_v<T> && has_m_tied<T>::value);
+};
+
+template <typename... Ts>
+constexpr bool tied_class_v = tied_class<Ts...>::value;
+
+////////////////
+// converter
+////////////////
+
+template <typename... Matchers>
+class converter {
+    using line_ptr_type = typename splitter<Matchers...>::line_ptr_type;
+
+    constexpr static auto string_error = setup<Matchers...>::string_error;
+    constexpr static auto default_delimiter = ",";
+
+    using error_type = ss::ternary_t<string_error, std::string, bool>;
+
+public:
+    // parses line with given delimiter, returns a 'T' object created with
+    // extracted values of type 'Ts'
+    template <typename T, typename... Ts>
+    T convert_object(line_ptr_type line,
+                     const std::string& delim = default_delimiter) {
+        return to_object<T>(convert<Ts...>(line, delim));
+    }
+
+    // parses line with given delimiter, returns tuple of objects with
+    // extracted values of type 'Ts'
+    template <typename... Ts>
+    no_void_validator_tup_t<Ts...> convert(
+        line_ptr_type line, const std::string& delim = default_delimiter) {
+        split(line, delim);
+        return convert<Ts...>(splitter_.split_data_);
+    }
+
+    // parses already split line, returns 'T' object with extracted values
+    template <typename T, typename... Ts>
+    T convert_object(const split_data& elems) {
+        return to_object<T>(convert<Ts...>(elems));
+    }
+
+    // same as above, but uses cached split line
+    template <typename T, typename... Ts>
+    T convert_object() {
+        return to_object<T>(convert<Ts...>());
+    }
+
+    // parses already split line, returns either a tuple of objects with
+    // parsed values (returns raw element (no tuple) if Ts is empty), or if
+    // one argument is given which is a class which has a tied
+    // method which returns a tuple, returns that type
+    template <typename T, typename... Ts>
+    no_void_validator_tup_t<T, Ts...> convert(const split_data& elems) {
+        if constexpr (sizeof...(Ts) == 0 && is_instance_of_v<std::tuple, T>) {
+            return convert_impl(elems, static_cast<T*>(nullptr));
+        } else if constexpr (tied_class_v<T, Ts...>) {
+            using arg_ref_tuple = std::result_of_t<decltype (&T::tied)(T)>;
+            using arg_tuple = apply_trait_t<std::decay, arg_ref_tuple>;
+
+            return to_object<T>(
+                convert_impl(elems, static_cast<arg_tuple*>(nullptr)));
+        } else {
+            return convert_impl<T, Ts...>(elems);
+        }
+    }
+
+    // same as above, but uses cached split line
+    template <typename T, typename... Ts>
+    no_void_validator_tup_t<T, Ts...> convert() {
+        return convert<T, Ts...>(splitter_.split_data_);
+    }
+
+    bool valid() const {
+        if constexpr (string_error) {
+            return error_.empty();
+        } else {
+            return !error_;
+        }
+    }
+
+    const std::string& error_msg() const {
+        assert_string_error_defined<string_error>();
+        return error_;
+    }
+
+    bool unterminated_quote() const {
+        return splitter_.unterminated_quote();
+    }
+
+    // 'splits' string by given delimiter, returns vector of pairs which
+    // contain the beginnings and the ends of each column of the string
+    const split_data& split(line_ptr_type line,
+                            const std::string& delim = default_delimiter) {
+        splitter_.split_data_.clear();
+        if (line[0] == '\0') {
+            return splitter_.split_data_;
+        }
+
+        return splitter_.split(line, delim);
+    }
+
+private:
+    ////////////////
+    // resplit
+    ////////////////
+
+    const split_data& resplit(line_ptr_type new_line, ssize_t new_size,
+                              const std::string& delim = default_delimiter) {
+        return splitter_.resplit(new_line, new_size, delim);
+    }
+
+    size_t size_shifted() {
+        return splitter_.size_shifted();
+    }
+
+    ////////////////
+    // error
+    ////////////////
+
+    void clear_error() {
+        if constexpr (string_error) {
+            error_.clear();
+        } else {
+            error_ = false;
+        }
+    }
+
+    std::string error_sufix(const string_range msg, size_t pos) const {
+        std::string error;
+        error.reserve(32);
+        error.append("at column ")
+            .append(std::to_string(pos + 1))
+            .append(": \'")
+            .append(msg.first, msg.second)
+            .append("\'");
+        return error;
+    }
+
+    void set_error_unterminated_quote() {
+        if constexpr (string_error) {
+            error_.clear();
+            error_.append(splitter_.error_msg());
+        } else {
+            error_ = true;
+        }
+    }
+
+    void set_error_unterminated_escape() {
+        if constexpr (string_error) {
+            error_.clear();
+            splitter_.set_error_unterminated_escape();
+            error_.append(splitter_.error_msg());
+        } else {
+            error_ = true;
+        }
+    }
+
+    void set_error_multiline_limit_reached() {
+        if constexpr (string_error) {
+            error_.clear();
+            error_.append("multiline limit reached.");
+        } else {
+            error_ = true;
+        }
+    }
+
+    void set_error_invalid_conversion(const string_range msg, size_t pos) {
+        if constexpr (string_error) {
+            error_.clear();
+            error_.append("invalid conversion for parameter ")
+                .append(error_sufix(msg, pos));
+        } else {
+            error_ = true;
+        }
+    }
+
+    void set_error_validate(const char* const error, const string_range msg,
+                            size_t pos) {
+        if constexpr (string_error) {
+            error_.clear();
+            error_.append(error).append(" ").append(error_sufix(msg, pos));
+        } else {
+            error_ = true;
+        }
+    }
+
+    void set_error_number_of_columns(size_t expected_pos, size_t pos) {
+        if constexpr (string_error) {
+            error_.clear();
+            error_.append("invalid number of columns, expected: ")
+                .append(std::to_string(expected_pos))
+                .append(", got: ")
+                .append(std::to_string(pos));
+        } else {
+            error_ = true;
+        }
+    }
+
+    void set_error_incompatible_mapping(size_t argument_size,
+                                        size_t mapping_size) {
+        if constexpr (string_error) {
+            error_.clear();
+            error_
+                .append(
+                    "number of arguments does not match mapping, expected: ")
+                .append(std::to_string(mapping_size))
+                .append(", got: ")
+                .append(std::to_string(argument_size));
+        } else {
+            error_ = true;
+        }
+    }
+
+    void set_error_invalid_mapping() {
+        if constexpr (string_error) {
+            error_.clear();
+            error_.append("received empty mapping");
+        } else {
+            error_ = true;
+        }
+    }
+
+    void set_error_mapping_out_of_range(size_t maximum_index,
+                                        size_t number_of_columnts) {
+        if constexpr (string_error) {
+            error_.clear();
+            error_.append("maximum index: ")
+                .append(std::to_string(maximum_index))
+                .append(", greater then number of columns: ")
+                .append(std::to_string(number_of_columnts));
+        } else {
+            error_ = true;
+        }
+    }
+
+    ////////////////
+    // convert implementation
+    ////////////////
+
+    template <typename... Ts>
+    no_void_validator_tup_t<Ts...> convert_impl(const split_data& elems) {
+        clear_error();
+        using return_type = no_void_validator_tup_t<Ts...>;
+
+        if (!splitter_.valid()) {
+            set_error_unterminated_quote();
+            no_void_validator_tup_t<Ts...> ret{};
+            return ret;
+        }
+
+        if (!columns_mapped()) {
+            if (sizeof...(Ts) != elems.size()) {
+                set_error_number_of_columns(sizeof...(Ts), elems.size());
+                return return_type{};
+            }
+        } else {
+            if (sizeof...(Ts) != column_mappings_.size()) {
+                set_error_incompatible_mapping(sizeof...(Ts),
+                                               column_mappings_.size());
+                return return_type{};
+            }
+
+            if (elems.size() != number_of_columns_) {
+                set_error_number_of_columns(number_of_columns_, elems.size());
+                return return_type{};
+            }
+        }
+
+        return extract_tuple<Ts...>(elems);
+    }
+
+    // do not know how to specialize by return type :(
+    template <typename... Ts>
+    no_void_validator_tup_t<std::tuple<Ts...>> convert_impl(
+        const split_data& elems, const std::tuple<Ts...>*) {
+        return convert_impl<Ts...>(elems);
+    }
+
+    ////////////////
+    // column mapping
+    ////////////////
+
+    bool columns_mapped() const {
+        return column_mappings_.size() != 0;
+    }
+
+    size_t column_position(size_t tuple_position) const {
+        if (!columns_mapped()) {
+            return tuple_position;
+        }
+        return column_mappings_[tuple_position];
+    }
+
+    void set_column_mapping(std::vector<size_t> positions,
+                            size_t number_of_columns) {
+        if (positions.empty()) {
+            set_error_invalid_mapping();
+            return;
+        }
+
+        auto max_index = *std::max_element(positions.begin(), positions.end());
+        if (max_index >= number_of_columns) {
+            set_error_mapping_out_of_range(max_index, number_of_columns);
+            return;
+        }
+
+        column_mappings_ = positions;
+        number_of_columns_ = number_of_columns;
+    }
+
+    void clear_column_positions() {
+        column_mappings_.clear();
+        number_of_columns_ = 0;
+    }
+
+    ////////////////
+    // conversion
+    ////////////////
+
+    template <typename T>
+    void extract_one(no_validator_t<T>& dst, const string_range msg,
+                     size_t pos) {
+        if (!valid()) {
+            return;
+        }
+
+        if constexpr (std::is_same_v<T, std::string>) {
+            extract(msg.first, msg.second, dst);
+            return;
+        }
+
+        if (!extract(msg.first, msg.second, dst)) {
+            set_error_invalid_conversion(msg, pos);
+            return;
+        }
+
+        if constexpr (has_m_ss_valid_t<T>) {
+            if (T validator; !validator.ss_valid(dst)) {
+                if constexpr (has_m_error_t<T>) {
+                    set_error_validate(validator.error(), msg, pos);
+                } else {
+                    set_error_validate("validation error", msg, pos);
+                }
+                return;
+            }
+        }
+    }
+
+    template <size_t ArgN, size_t TupN, typename... Ts>
+    void extract_multiple(no_void_validator_tup_t<Ts...>& tup,
+                          const split_data& elems) {
+        using elem_t = std::tuple_element_t<ArgN, std::tuple<Ts...>>;
+
+        constexpr bool not_void = !std::is_void_v<elem_t>;
+        constexpr bool one_element = count_not_v<std::is_void, Ts...> == 1;
+
+        if constexpr (not_void) {
+            if constexpr (one_element) {
+                extract_one<elem_t>(tup, elems[column_position(ArgN)], ArgN);
+            } else {
+                auto& el = std::get<TupN>(tup);
+                extract_one<elem_t>(el, elems[column_position(ArgN)], ArgN);
+            }
+        }
+
+        if constexpr (sizeof...(Ts) > ArgN + 1) {
+            constexpr size_t NewTupN = (not_void) ? TupN + 1 : TupN;
+            extract_multiple<ArgN + 1, NewTupN, Ts...>(tup, elems);
+        }
+    }
+
+    template <typename... Ts>
+    no_void_validator_tup_t<Ts...> extract_tuple(const split_data& elems) {
+        static_assert(!all_of_v<std::is_void, Ts...>,
+                      "at least one parameter must be non void");
+        no_void_validator_tup_t<Ts...> ret{};
+        extract_multiple<0, 0, Ts...>(ret, elems);
+        return ret;
+    }
+
+    ////////////////
+    // members
+    ////////////////
+
+    error_type error_{};
+    splitter<Matchers...> splitter_;
+
+    template <typename...>
+    friend class parser;
+
+    std::vector<size_t> column_mappings_;
+    size_t number_of_columns_;
+};
+
+} /* ss */
+
+
+namespace ss {
+
+template <typename... Matchers>
+class parser {
+    constexpr static auto string_error = setup<Matchers...>::string_error;
+
+    using multiline = typename setup<Matchers...>::multiline;
+    using error_type = ss::ternary_t<string_error, std::string, bool>;
+
+    constexpr static bool escaped_multiline_enabled =
+        multiline::enabled && setup<Matchers...>::escape::enabled;
+
+    constexpr static bool quoted_multiline_enabled =
+        multiline::enabled && setup<Matchers...>::quote::enabled;
+
+    constexpr static bool ignore_header = setup<Matchers...>::ignore_header;
+
+    constexpr static bool ignore_empty = setup<Matchers...>::ignore_empty;
+
+public:
+    parser(const std::string& file_name,
+           const std::string& delim = ss::default_delimiter)
+        : file_name_{file_name}, reader_{file_name_, delim} {
+        if (reader_.file_) {
+            read_line();
+            if constexpr (ignore_header) {
+                ignore_next();
+            } else {
+                header_ = reader_.get_next_row();
+            }
+        } else {
+            set_error_file_not_open();
+            eof_ = true;
+        }
+    }
+
+    parser(parser&& other) = default;
+    parser& operator=(parser&& other) = default;
+
+    parser() = delete;
+    parser(const parser& other) = delete;
+    parser& operator=(const parser& other) = delete;
+
+    bool valid() const {
+        if constexpr (string_error) {
+            return error_.empty();
+        } else {
+            return !error_;
+        }
+    }
+
+    const std::string& error_msg() const {
+        assert_string_error_defined<string_error>();
+        return error_;
+    }
+
+    bool eof() const {
+        return eof_;
+    }
+
+    bool ignore_next() {
+        return reader_.read_next();
+    }
+
+    template <typename T, typename... Ts>
+    T get_object() {
+        return to_object<T>(get_next<Ts...>());
+    }
+
+    size_t line() const {
+        return valid() ? reader_.line_number_ - 1 : 0;
+    }
+
+    template <typename T, typename... Ts>
+    no_void_validator_tup_t<T, Ts...> get_next() {
+        reader_.update();
+        clear_error();
+        if (eof_) {
+            set_error_eof_reached();
+            return {};
+        }
+
+        auto value = reader_.converter_.template convert<T, Ts...>();
+
+        if (!reader_.converter_.valid()) {
+            set_error_invalid_conversion();
+        }
+
+        read_line();
+        return value;
+    }
+
+    bool field_exists(const std::string& field) {
+        return header_index(field).has_value();
+    }
+
+    template <typename... Ts>
+    void use_fields(const Ts&... fields_args) {
+        if constexpr (ignore_header) {
+            set_error_header_ignored();
+            return;
+        }
+
+        if (!valid()) {
+            return;
+        }
+
+        auto fields = std::vector<std::string>{fields_args...};
+        std::vector<size_t> column_mappings;
+
+        for (const auto& field : fields) {
+            if (std::count(fields.begin(), fields.end(), field) != 1) {
+                set_error_field_used_multiple_times(field);
+                return;
+            }
+
+            auto index = header_index(field);
+
+            if (!index) {
+                set_error_invalid_field(field);
+                return;
+            }
+
+            column_mappings.push_back(*index);
+        }
+
+        reader_.converter_.set_column_mapping(column_mappings, header_.size());
+        reader_.next_line_converter_.set_column_mapping(column_mappings,
+                                                        header_.size());
+        if (line() == 0) {
+            ignore_next();
+        }
+    }
+
+    ////////////////
+    // iterator
+    ////////////////
+
+    template <bool get_object, typename T, typename... Ts>
+    struct iterable {
+        struct iterator {
+            using value =
+                ss::ternary_t<get_object, T, no_void_validator_tup_t<T, Ts...>>;
+
+            iterator() : parser_{nullptr} {
+            }
+            iterator(parser<Matchers...>* parser) : parser_{parser} {
+            }
+
+            value& operator*() {
+                return value_;
+            }
+            value* operator->() {
+                return &value_;
+            }
+
+            iterator& operator++() {
+                if (parser_->eof()) {
+                    parser_ = nullptr;
+                } else {
+                    if constexpr (get_object) {
+                        value_ =
+                            std::move(parser_->template get_object<T, Ts...>());
+                    } else {
+                        value_ =
+                            std::move(parser_->template get_next<T, Ts...>());
+                    }
+                }
+                return *this;
+            }
+
+            iterator& operator++(int) {
+                return ++*this;
+            }
+
+            friend bool operator==(const iterator& lhs, const iterator& rhs) {
+                return (lhs.parser_ == nullptr && rhs.parser_ == nullptr) ||
+                       (lhs.parser_ == rhs.parser_ &&
+                        &lhs.value_ == &rhs.value_);
+            }
+
+            friend bool operator!=(const iterator& lhs, const iterator& rhs) {
+                return !(lhs == rhs);
+            }
+
+        private:
+            value value_;
+            parser<Matchers...>* parser_;
+        };
+
+        iterable(parser<Matchers...>* parser) : parser_{parser} {
+        }
+
+        iterator begin() {
+            return ++iterator{parser_};
+        }
+        iterator end() {
+            return iterator{};
+        }
+
+    private:
+        parser<Matchers...>* parser_;
+    };
+
+    template <typename... Ts>
+    auto iterate() {
+        return iterable<false, Ts...>{this};
+    }
+
+    template <typename... Ts>
+    auto iterate_object() {
+        return iterable<true, Ts...>{this};
+    }
+
+    ////////////////
+    // composite conversion
+    ////////////////
+    template <typename... Ts>
+    class composite {
+    public:
+        composite(std::tuple<Ts...>&& values, parser& parser)
+            : values_{std::move(values)}, parser_{parser} {
+        }
+
+        // tries to convert the same line with a different output type
+        // only if the previous conversion was not successful,
+        // returns composite containing itself and the new output
+        // as optional, additionally, if a parameter is passed, and
+        // that parameter can be invoked using the converted value,
+        // than it will be invoked in the case of a valid conversion
+        template <typename... Us, typename Fun = none>
+        composite<Ts..., std::optional<no_void_validator_tup_t<Us...>>> or_else(
+            Fun&& fun = none{}) {
+            using Value = no_void_validator_tup_t<Us...>;
+            std::optional<Value> value;
+            try_convert_and_invoke<Value, Us...>(value, fun);
+            return composite_with(std::move(value));
+        }
+
+        // same as or_else, but saves the result into a 'U' object
+        // instead of a tuple
+        template <typename U, typename... Us, typename Fun = none>
+        composite<Ts..., std::optional<U>> or_object(Fun&& fun = none{}) {
+            std::optional<U> value;
+            try_convert_and_invoke<U, Us...>(value, fun);
+            return composite_with(std::move(value));
+        }
+
+        std::tuple<Ts...> values() {
+            return values_;
+        }
+
+        template <typename Fun>
+        auto on_error(Fun&& fun) {
+            if (!parser_.valid()) {
+                if constexpr (std::is_invocable_v<Fun>) {
+                    fun();
+                } else {
+                    static_assert(string_error,
+                                  "to enable error messages within the "
+                                  "on_error method "
+                                  "callback string_error needs to be enabled");
+                    std::invoke(std::forward<Fun>(fun), parser_.error_msg());
+                }
+            }
+            return *this;
+        }
+
+    private:
+        template <typename T>
+        composite<Ts..., T> composite_with(T&& new_value) {
+            auto merged_values =
+                std::tuple_cat(std::move(values_),
+                               std::tuple<T>{parser_.valid()
+                                                 ? std::forward<T>(new_value)
+                                                 : std::nullopt});
+            return {std::move(merged_values), parser_};
+        }
+
+        template <typename U, typename... Us, typename Fun = none>
+        void try_convert_and_invoke(std::optional<U>& value, Fun&& fun) {
+            if (!parser_.valid()) {
+                auto tuple_output = try_same<Us...>();
+                if (!parser_.valid()) {
+                    return;
+                }
+
+                if constexpr (!std::is_same_v<U, decltype(tuple_output)>) {
+                    value = to_object<U>(std::move(tuple_output));
+                } else {
+                    value = std::move(tuple_output);
+                }
+
+                parser_.try_invoke(*value, std::forward<Fun>(fun));
+            }
+        }
+
+        template <typename U, typename... Us>
+        no_void_validator_tup_t<U, Us...> try_same() {
+            parser_.clear_error();
+            auto value =
+                parser_.reader_.converter_.template convert<U, Us...>();
+            if (!parser_.reader_.converter_.valid()) {
+                parser_.set_error_invalid_conversion();
+            }
+            return value;
+        }
+
+        ////////////////
+        // members
+        ////////////////
+
+        std::tuple<Ts...> values_;
+        parser& parser_;
+    };
+
+    // tries to convert a line and returns a composite which is
+    // able to try additional conversions in case of failure
+    template <typename... Ts, typename Fun = none>
+    composite<std::optional<no_void_validator_tup_t<Ts...>>> try_next(
+        Fun&& fun = none{}) {
+        using Ret = no_void_validator_tup_t<Ts...>;
+        return try_invoke_and_make_composite<
+            std::optional<Ret>>(get_next<Ts...>(), std::forward<Fun>(fun));
+    }
+
+    // identical to try_next but returns composite with object instead of a
+    // tuple
+    template <typename T, typename... Ts, typename Fun = none>
+    composite<std::optional<T>> try_object(Fun&& fun = none{}) {
+        return try_invoke_and_make_composite<
+            std::optional<T>>(get_object<T, Ts...>(), std::forward<Fun>(fun));
+    }
+
+private:
+    // tries to invoke the given function (see below), if the function
+    // returns a value which can be used as a conditional, and it returns
+    // false, the function sets an error, and allows the invoke of the
+    // next possible conversion as if the validation of the current one
+    // failed
+    template <typename Arg, typename Fun = none>
+    void try_invoke(Arg&& arg, Fun&& fun) {
+        constexpr bool is_none = std::is_same_v<std::decay_t<Fun>, none>;
+        if constexpr (!is_none) {
+            using Ret = decltype(try_invoke_impl(arg, std::forward<Fun>(fun)));
+            constexpr bool returns_void = std::is_same_v<Ret, void>;
+            if constexpr (!returns_void) {
+                if (!try_invoke_impl(arg, std::forward<Fun>(fun))) {
+                    set_error_failed_check();
+                }
+            } else {
+                try_invoke_impl(arg, std::forward<Fun>(fun));
+            }
+        }
+    }
+
+    // tries to invoke the function if not none
+    // it first tries to invoke the function without arguments,
+    // than with one argument if the function accepts the whole tuple
+    // as an argument, and finally tries to invoke it with the tuple
+    // laid out as a parameter pack
+    template <typename Arg, typename Fun = none>
+    auto try_invoke_impl(Arg&& arg, Fun&& fun) {
+        constexpr bool is_none = std::is_same_v<std::decay_t<Fun>, none>;
+        if constexpr (!is_none) {
+            if constexpr (std::is_invocable_v<Fun>) {
+                return fun();
+            } else if constexpr (std::is_invocable_v<Fun, Arg>) {
+                return std::invoke(std::forward<Fun>(fun),
+                                   std::forward<Arg>(arg));
+            } else {
+                return std::apply(std::forward<Fun>(fun),
+                                  std::forward<Arg>(arg));
+            }
+        }
+    }
+
+    template <typename T, typename Fun = none>
+    composite<T> try_invoke_and_make_composite(T&& value, Fun&& fun) {
+        if (valid()) {
+            try_invoke(*value, std::forward<Fun>(fun));
+        }
+        return {valid() ? std::move(value) : std::nullopt, *this};
+    }
+
+    ////////////////
+    // header
+    ////////////////
+
+    std::optional<size_t> header_index(const std::string& field) {
+        auto it = std::find(header_.begin(), header_.end(), field);
+
+        if (it == header_.end()) {
+            return std::nullopt;
+        }
+
+        return std::distance(header_.begin(), it);
+    }
+
+    ////////////////
+    // error
+    ////////////////
+
+    void clear_error() {
+        if constexpr (string_error) {
+            error_.clear();
+        } else {
+            error_ = false;
+        }
+    }
+
+    void set_error_failed_check() {
+        if constexpr (string_error) {
+            error_.append(file_name_).append(" failed check.");
+        } else {
+            error_ = true;
+        }
+    }
+
+    void set_error_file_not_open() {
+        if constexpr (string_error) {
+            error_.append(file_name_).append(" could not be opened.");
+        } else {
+            error_ = true;
+        }
+    }
+
+    void set_error_eof_reached() {
+        if constexpr (string_error) {
+            error_.append(file_name_).append(" reached end of file.");
+        } else {
+            error_ = true;
+        }
+    }
+
+    void set_error_invalid_conversion() {
+        if constexpr (string_error) {
+            error_.append(file_name_)
+                .append(" ")
+                .append(std::to_string(reader_.line_number_))
+                .append(": ")
+                .append(reader_.converter_.error_msg())
+                .append(": \"")
+                .append(reader_.buffer_)
+                .append("\"");
+        } else {
+            error_ = true;
+        }
+    }
+
+    void set_error_header_ignored() {
+        if constexpr (string_error) {
+            error_.append(file_name_)
+                .append(": \"")
+                .append("the header row is ignored within the setup, it cannot "
+                        "be used")
+                .append("\"");
+        } else {
+            error_ = true;
+        }
+    }
+
+    void set_error_invalid_field(const std::string& field) {
+        if constexpr (string_error) {
+            error_.append(file_name_)
+                .append(": header does not contain given field: ")
+                .append(field);
+        } else {
+            error_ = true;
+        }
+    }
+
+    void set_error_field_used_multiple_times(const std::string& field) {
+        if constexpr (string_error) {
+            error_.append(file_name_)
+                .append(": given field used multiple times: ")
+                .append(field);
+        } else {
+            error_ = true;
+        }
+    }
+
+    ////////////////
+    // line reading
+    ////////////////
+
+    void read_line() {
+        eof_ = !reader_.read_next();
+    }
+
+    struct reader {
+        reader(const std::string& file_name_, const std::string& delim)
+            : delim_{delim}, file_{fopen(file_name_.c_str(), "rb")} {
+        }
+
+        reader(reader&& other)
+            : buffer_{other.buffer_},
+              next_line_buffer_{other.next_line_buffer_},
+              helper_buffer_{other.helper_buffer_}, converter_{std::move(
+                                                        other.converter_)},
+              next_line_converter_{std::move(other.next_line_converter_)},
+              size_{other.size_}, next_line_size_{other.next_line_size_},
+              helper_size_{other.helper_size_}, delim_{std::move(other.delim_)},
+              file_{other.file_}, crlf_{other.crlf_}, line_number_{
+                                                          other.line_number_} {
+            other.buffer_ = nullptr;
+            other.next_line_buffer_ = nullptr;
+            other.helper_buffer_ = nullptr;
+            other.file_ = nullptr;
+        }
+
+        reader& operator=(reader&& other) {
+            if (this != &other) {
+                buffer_ = other.buffer_;
+                next_line_buffer_ = other.next_line_buffer_;
+                helper_buffer_ = other.helper_buffer_;
+                converter_ = std::move(other.converter_);
+                next_line_converter_ = std::move(other.next_line_converter_);
+                size_ = other.size_;
+                next_line_size_ = other.next_line_size_;
+                helper_size_ = other.helper_size_;
+                delim_ = std::move(other.delim_);
+                file_ = other.file_;
+                crlf_ = other.crlf_;
+                line_number_ = other.line_number_;
+
+                other.buffer_ = nullptr;
+                other.next_line_buffer_ = nullptr;
+                other.helper_buffer_ = nullptr;
+                other.file_ = nullptr;
+            }
+
+            return *this;
+        }
+
+        ~reader() {
+            free(buffer_);
+            free(next_line_buffer_);
+            free(helper_buffer_);
+
+            if (file_) {
+                fclose(file_);
+            }
+        }
+
+        reader() = delete;
+        reader(const reader& other) = delete;
+        reader& operator=(const reader& other) = delete;
+
+        bool read_next() {
+
+            ssize_t ssize;
+            size_t size = 0;
+            while (size == 0) {
+                ++line_number_;
+                if (next_line_size_ > 0) {
+                    next_line_buffer_[0] = '\0';
+                }
+                ssize = get_line(&next_line_buffer_, &next_line_size_, file_);
+
+                if (ssize == -1) {
+                    return false;
+                }
+
+                size = remove_eol(next_line_buffer_, ssize);
+
+                if constexpr (!ignore_empty) {
+                    break;
+                }
+            }
+
+            size_t limit = 0;
+
+            if constexpr (escaped_multiline_enabled) {
+                while (escaped_eol(size)) {
+                    if (multiline_limit_reached(limit)) {
+                        return true;
+                    }
+                    if (!append_next_line_to_buffer(next_line_buffer_, size)) {
+                        remove_eol(next_line_buffer_, ssize);
+                        next_line_converter_.set_error_unterminated_escape();
+                        return true;
+                    }
+                }
+            }
+
+            next_line_converter_.split(next_line_buffer_, delim_);
+
+            if constexpr (quoted_multiline_enabled) {
+                while (unterminated_quote()) {
+                    if (multiline_limit_reached(limit)) {
+                        return true;
+                    }
+                    if (!append_next_line_to_buffer(next_line_buffer_, size)) {
+                        remove_eol(next_line_buffer_, ssize);
+                        return true;
+                    }
+
+                    if constexpr (escaped_multiline_enabled) {
+                        while (escaped_eol(size)) {
+                            if (multiline_limit_reached(limit)) {
+                                return true;
+                            }
+                            if (!append_next_line_to_buffer(next_line_buffer_,
+                                                            size)) {
+                                remove_eol(next_line_buffer_, ssize);
+                                next_line_converter_
+                                    .set_error_unterminated_escape();
+                                return true;
+                            }
+                        }
+                    }
+
+                    next_line_converter_.resplit(next_line_buffer_, size);
+                }
+            }
+
+            return true;
+        }
+
+        void update() {
+            std::swap(buffer_, next_line_buffer_);
+            std::swap(size_, next_line_size_);
+            std::swap(converter_, next_line_converter_);
+        }
+
+        bool multiline_limit_reached(size_t& limit) {
+            if constexpr (multiline::size > 0) {
+                if (limit++ >= multiline::size) {
+                    next_line_converter_.set_error_multiline_limit_reached();
+                    return true;
+                }
+            }
+            return false;
+        }
+
+        bool escaped_eol(size_t size) {
+            const char* curr;
+            for (curr = next_line_buffer_ + size - 1;
+                 curr >= next_line_buffer_ &&
+                 setup<Matchers...>::escape::match(*curr);
+                 --curr) {
+            }
+            return (next_line_buffer_ - curr + size) % 2 == 0;
+        }
+
+        bool unterminated_quote() {
+            if (next_line_converter_.unterminated_quote()) {
+                return true;
+            }
+            return false;
+        }
+
+        void undo_remove_eol(char* buffer, size_t& string_end) {
+            if (next_line_converter_.unterminated_quote()) {
+                string_end -= next_line_converter_.size_shifted();
+            }
+            if (crlf_) {
+                std::copy_n("\r\n\0", 3, buffer + string_end);
+                string_end += 2;
+            } else {
+                std::copy_n("\n\0", 2, buffer + string_end);
+                string_end += 1;
+            }
+        }
+
+        size_t remove_eol(char*& buffer, size_t size) {
+            size_t new_size = size - 1;
+            if (size >= 2 && buffer[size - 2] == '\r') {
+                crlf_ = true;
+                new_size--;
+            } else {
+                crlf_ = false;
+            }
+
+            buffer[new_size] = '\0';
+            return new_size;
+        }
+
+        void realloc_concat(char*& first, size_t& first_size,
+                            const char* const second, size_t second_size) {
+            next_line_size_ = first_size + second_size + 3;
+            first = static_cast<char*>(
+                realloc(static_cast<void*>(first), next_line_size_));
+            std::copy_n(second, second_size + 1, first + first_size);
+            first_size += second_size;
+        }
+
+        bool append_next_line_to_buffer(char*& buffer, size_t& size) {
+            undo_remove_eol(buffer, size);
+
+            ssize_t next_ssize =
+                get_line(&helper_buffer_, &helper_size_, file_);
+            if (next_ssize == -1) {
+                return false;
+            }
+
+            ++line_number_;
+            size_t next_size = remove_eol(helper_buffer_, next_ssize);
+            realloc_concat(buffer, size, helper_buffer_, next_size);
+            return true;
+        }
+
+        std::vector<std::string> get_next_row() const {
+            std::vector<std::string> next_row;
+            auto& next_row_raw = next_line_converter_.splitter_.split_data_;
+            for (const auto& [begin, end] : next_row_raw) {
+                next_row.emplace_back(begin, end);
+            }
+            return next_row;
+        }
+
+        ////////////////
+        // members
+        ////////////////
+        char* buffer_{nullptr};
+        char* next_line_buffer_{nullptr};
+        char* helper_buffer_{nullptr};
+
+        converter<Matchers...> converter_;
+        converter<Matchers...> next_line_converter_;
+
+        size_t size_{0};
+        size_t next_line_size_{0};
+        size_t helper_size_{0};
+
+        std::string delim_;
+        FILE* file_{nullptr};
+
+        bool crlf_;
+        size_t line_number_{0};
+    };
+
+    ////////////////
+    // members
+    ////////////////
+
+    std::string file_name_;
+    error_type error_{};
+    reader reader_;
+    std::vector<std::string> header_;
+    bool eof_{false};
+};
+
+} /* ss */