charclass.hpp File Reference

256-bit byte set with O(1) membership, fully constexpr. More...

#include "real/version.hpp"
#include <array>
#include <cstddef>
#include <cstdint>

Include dependency graph for charclass.hpp:

Classes
struct	real::detail::char_class
	A set of byte values (0–255) as a 256-bit bitmap. More...
struct	real::detail::utf8_second_byte_bounds
	[lo, hi] bounds for the FIRST continuation byte of a multi-byte UTF-8 sequence, given its lead byte — one entry of utf8_second_byte_bounds_table. More...

Namespaces
namespace	real
	REAL's public API: real::regex, real::static_regex, real::flags and the match/iterator types built on them.
namespace	real::detail
	DFA construction internals: subset construction over a flattened NFA. Not a stable API.

Functions
constexpr void	real::detail::fold_ascii_case (char_class &klass)
	Closes klass under ASCII case folding.
constexpr bool	real::detail::is_ascii_word_byte (std::uint8_t byte)
	Reports whether byte is an ASCII "word" byte ([0-9A-Za-z_]).
constexpr char_class	real::detail::digit_set ()
	The ASCII digit set behind \d (Python re.ASCII semantics).
constexpr char_class	real::detail::word_set ()
	The ASCII word set behind \w.
constexpr char_class	real::detail::space_set ()
	The ASCII whitespace set behind \s under flags::ascii / flags::bytes.
constexpr char_class	real::detail::utf8_cont_set ()
	The UTF-8 continuation-byte set 10xxxxxx.
constexpr char_class	real::detail::utf8_lead2_set ()
	The lead-byte set of a 2-byte UTF-8 sequence.
constexpr char_class	real::detail::utf8_lead3_set ()
	The lead-byte set of a 3-byte UTF-8 sequence.
constexpr char_class	real::detail::utf8_lead4_set ()
	The lead-byte set of a 4-byte UTF-8 sequence.
constexpr std::array< utf8_second_byte_bounds, 256 >	real::detail::make_utf8_second_byte_bounds_table ()
	Builds utf8_second_byte_bounds_table (a plain function so the 256-entry table is four lines of exceptions, not a 256-line literal).

Variables
constexpr std::array< utf8_second_byte_bounds, 256 >	real::detail::utf8_second_byte_bounds_table
	First-continuation-byte bounds indexed by lead byte (0–255; only 0xC2–0xF4 are ever consulted). inline constexpr: computed once at compile time, one instance across TUs.

Detailed Description

256-bit byte set with O(1) membership, fully constexpr.

The engine only ever tests bitmaps: negation and "one whole codepoint" semantics are resolved at compile time (see compiler.hpp), never at match time. Also holds the ASCII sets behind \d, \w and \s, the UTF-8 lead/continuation byte sets that . and negated classes expand to, and the per-lead bounds that reject a malformed sequence without decoding it.