Module class 

The byte classes of the ABNF, in one table.

One static table of 256 u32 entries (1 KiB), built at compile time from the ABNF, holds one bit per class, so classifying a byte is one load and one mask. The table is the single reviewable source of every class; the tests compare it, for all 256 bytes, with slow functions written straight from the RFC text.

Every class is ASCII-only except OBS_TEXT, FIELD_TEXT, QDTEXT, CTEXT, QUOTED_PAIR, and ETAGC, which include 0x80 to 0xFF as obs-text. DEL (0x7F) is in no class.

Examples

use parse_net::class::{self, Class};

assert!(class::is_tchar(b'!') && !class::is_tchar(b'('));
assert!(class::is_mime_token_char(b'{') && !class::is_tchar(b'{'));
assert_eq!(class::hex_value(b'f'), Some(15));
assert!(class::all(b"no-cache", Class::TCHAR));
assert!(Class::UNRESERVED.union(Class::SUB_DELIM).contains(b'~'));

Structs

Class

A set of byte classes, for all and the scanning functions.

Functions

all

Whether every byte of s is in class (true for an empty s). Stops at the first byte outside.

hex_value

The value of one hex digit (either case), or None.

is_atext

Whether b is an atext byte (RFC 5322 section 3.2.3).

is_attr_char

Whether b is an attr-char (RFC 8187 section 3.2.1).

is_av_octet

Whether b may appear in a cookie attribute value (rfc6265bis section 4.1.1).

is_base64_char

Whether b is in the base64 alphabet (RFC 4648 section 4), padding aside.

is_bchar_nospace

Whether b is a bcharsnospace byte (RFC 2046 section 5.1.1).

is_cookie_octet

Whether b is a cookie-octet (rfc6265bis section 4.1.1).

is_ctext

Whether b may appear unescaped in a comment (RFC 9110 section 5.6.5).

is_etagc

Whether b is an etagc (RFC 9110 section 8.8.3).

is_field_text

Whether b may appear in a field value: field-vchar / SP / HTAB (RFC 9110 section 5.5).

is_hexdig

Whether b is a hex digit, either case.

is_mime_token_char

Whether b may appear in a MIME token (RFC 2045 section 5.1).

is_obs_text

Whether b is obs-text, 0x80 to 0xFF.

is_pchar_no_pct

Whether b is a pchar other than the % of pct-encoded (RFC 3986 section 3.3).

is_qdtext

Whether b may appear unescaped in a quoted string (RFC 9110 section 5.6.4).

is_quoted_pair_char

Whether b may follow \ in a quoted-pair: HTAB / SP / VCHAR / obs-text.

is_sf_key_char

Whether b may appear in a Structured Field key.

is_sf_key_start

Whether b may start a Structured Field key: lcalpha / "*".

is_sf_string_char

Whether b may appear unescaped in a Structured Field string.

is_sf_token_char

Whether b may appear in a Structured Field token after its first byte.

is_sub_delim

Whether b is a sub-delims byte (RFC 3986 section 2.2).

is_tchar

Whether b is a tchar, a byte allowed in a token (RFC 9110 section 5.6.2).

is_token68_char

Whether b is a token68 byte other than the = padding.

is_unreserved

Whether b is unreserved (RFC 3986 section 2.3).

is_uri_target

Whether b may appear in a request target: pchar / "/" / "?" or the % of a pct-encoded triple (whose digits are checked apart).

is_vchar

Whether b is a visible ASCII character, 0x21 to 0x7E.