const_fmt/inc/format.h

142 lines
3.1 KiB
C++

#ifndef LOGGER_FORMAT_H
#define LOGGER_FORMAT_H
#include <cstring>
#include "parse.h"
#include "utility.h"
#include "format_impl.h"
namespace detail {
/*
*
* Utility functions
*
*/
template <ConstString s>
constexpr inline int get_output_len() {
constexpr auto parse_result = parse_string<s>();
static_assert(parse_result.is_valid, "Syntax error in format string");
return get_ast_output_len<parse_result.value>();
}
template <fmt_node_t fmt_node, typename T>
constexpr inline void check_fmt_params() {
static_assert(fmt_node.length > fmt_node.precision + 1,
"Insufficient length for desired precision");
}
/*
*
* Formatting wrapper functions
*
*/
// TODO: Error handling
template <fmt_data_t fmt_data, std::integral arg_t>
constexpr inline void format_arg(char* dest, arg_t arg) {
auto error_array = get_init_array<fmt_data.length>('f');
detail::format_integral(dest, arg, fmt_data);
};
// TODO: Error handling
template <fmt_data_t fmt_data, std::floating_point arg_t>
constexpr inline void format_arg(char* dest, arg_t) {
*(dest) = 'f';
*(dest + fmt_data.length - fmt_data.precision - 1) = '.';
};
// TODO: Error handling
template<fmt_data_t fmt_data>
constexpr inline void format_arg(char* dest, const char* arg) {
const std::size_t len = const_strlen(arg);
if (len > fmt_data.length) return;
dest = dest + fmt_data.length - len;
if (!std::is_constant_evaluated()) {
std::memcpy(dest, arg, len);
return;
}
for (std::size_t i = 0; i < len; ++i) {
*(dest++) = *(arg++);
}
};
// End of recursion
template <auto ast>
constexpr inline void format_args(char*) {
}
template <auto fmt_data_array, typename first_arg_t, typename... args_t>
constexpr inline void format_args(char* dest, first_arg_t first_arg, args_t... args) {
format_arg<fmt_data_array[0]>(dest + fmt_data_array[0].position, first_arg);
format_args<drop_first(fmt_data_array)>(dest, args...);
}
template <auto ast>
consteval inline std::array<char, get_ast_output_len<ast>()> get_preproc_string() {
auto result = get_init_array<get_ast_output_len<ast>()>('0');
int i = 0;
for (const auto& ast_node : ast) {
if (ast_node.is_char())
result[i++] = ast_node.get_char();
else
i += ast_node.get_node().length;
}
return result;
}
} // namespace detail
/*
*
* Public API
*
*/
template <detail::ConstString s, typename... args_t>
constexpr inline auto format(args_t... args) {
constexpr auto ast = detail::parse_string<s>().value;
constexpr auto fmt_data = detail::get_fmt_data<ast>();
auto result = detail::get_preproc_string<ast>();
detail::format_args<fmt_data>(result.begin(), args...);
return result;
}
template<detail::ConstString t_s>
class fmt_literal_obj_t {
public:
template<typename... args_t>
constexpr auto operator()(args_t... args) {
return format<t_s>(args...);
}
};
template <detail::ConstString t_s>
constexpr auto operator""_fmt() {
return fmt_literal_obj_t<t_s>{};
}
#endif // LOGGER_FORMAT_H