utf8.hpp File Reference

UTF-8 position arithmetic for match iteration. More...

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

Include dependency graph for utf8.hpp:

Classes
struct	real::detail::decoded_codepoint
	The result of a strict UTF-8 decode: the code point, its byte length, and validity. 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 decoded_codepoint	real::detail::decode_codepoint_strict (std::string_view text, std::size_t pos)
	Strictly decodes and validates the UTF-8 sequence at text[pos].
constexpr std::size_t	real::detail::codepoint_advance (std::string_view text, std::size_t pos)
	Number of bytes from pos to the next code-point boundary, for advancing past an empty match during iteration.
constexpr std::size_t	real::detail::codepoint_retreat (std::string_view text, std::size_t end, std::size_t floor)
	Number of bytes from the code-point boundary immediately before end back to end – the mirror of codepoint_advance, for the width of the LAST code point in a well-formed run ending at end (a possessive cp-class loop's own last iteration: the loop only ever advanced by codepoint_advance-consistent steps, so walking backward over continuation bytes lands on the same boundary walking forward would have stopped at). Capped at 4 (the longest valid UTF-8 sequence) and never walks past floor, so a malformed/truncated run can never read out of the caller's own known-valid range.

Detailed Description

UTF-8 position arithmetic for match iteration.

The matching engine never needs this — multi-byte constructs are compiled to byte-level alternatives. It is used only by match iteration to advance past an empty match by one whole codepoint, matching Python's behaviour.