utf8_ranges.hpp File Reference

Code-point range → canonical UTF-8 byte-range sequences (RE2 / rust regex-syntax Utf8Sequences). More...

#include <cstddef>
#include <cstdint>
#include <vector>

Include dependency graph for utf8_ranges.hpp:

Classes
struct	real::detail::utf8_byte_range
	One byte-range step [lo, hi] of a UTF-8 sequence produced by the code-point-range algorithm. More...
struct	real::detail::utf8_byte_seq
	A canonical UTF-8 byte-range sequence (1–4 steps) covering part of a code-point range. 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 std::size_t	real::detail::encode_utf8_bytes (std::uint32_t cp, std::uint8_t(&out)[4])
	Encodes cp to its UTF-8 bytes in out, returning the length (1–4).
constexpr void	real::detail::utf8_push_range (std::uint32_t start, std::uint32_t end, std::vector< utf8_byte_seq > &out)
	Appends to out the byte-range sequences recognising exactly the UTF-8 encodings of [start, end] (RE2 / rust regex-syntax Utf8Sequences).
constexpr std::vector< utf8_byte_seq >	real::detail::utf8_range_sequences (std::uint32_t lo, std::uint32_t hi)
	Canonical UTF-8 byte-range sequences for the code-point range [lo, hi], excluding the surrogate block [U+D800, U+DFFF] (so a negated class never matches a surrogate encoding).

Detailed Description

Code-point range → canonical UTF-8 byte-range sequences (RE2 / rust regex-syntax Utf8Sequences).

Turning a code-point range [lo, hi] into the byte-range steps that recognise exactly its UTF-8 encodings — no overlong forms, no surrogate encodings — is needed in two places: the compiler expands . and negated classes this way, and the lazy DFA expands a klass_cp this way so a Unicode shorthand becomes a byte-transition sub-automaton. This header is the shared, dependency-light home of that algorithm — no engine header, only <cstddef>, <cstdint> and <vector> — so neither caller has to include the other.