Module hex 

Hexadecimal escapes shared by quoted-printable (=XX), percent-encoding (%XX) and xtext (+XX).

decode_pair is the primitive every decoder in the crate uses. The HexEscape engines apply a whole scheme: bytes outside the scheme’s safe set are written as a marker followed by two uppercase hexadecimal digits, and decoding turns every marker and the two digits after it back into a byte.

use encodify::hex;
use std::borrow::Cow;

assert_eq!(hex::PERCENT.encode("naïve.txt"), "na%C3%AFve.txt");
assert_eq!(hex::PERCENT.decode("na%c3%afve.txt")?, "naïve.txt".as_bytes());

assert_eq!(
    hex::XTEXT.encode("rfc822;a+b@example.org"),
    "rfc822;a+2Bb@example.org"
);
assert!(matches!(
    hex::XTEXT.decode("rfc822;user@example.org")?,
    Cow::Borrowed(_)
));

Structs

HexEscape

A hexadecimal escaping scheme: a marker byte followed by two hexadecimal digits stands for any byte outside the scheme’s safe set.

Constants

PERCENT

Percent-encoding (%XX). Encoding keeps the RFC 2231 attribute-char set (letters, digits and ! # $ & + - . ^ _ ` { | } ~) and escapes every other byte, as RFC 2231 extended parameter values require. It is not a URI component encoder: RFC 3986 reserves some of those characters. Decoding accepts any literal byte, so URIs and mailto: URLs decode too; + is not a space.

XTEXT

SMTP xtext (RFC 3461, +XX), used by the ENVID and ORCPT parameters. Encoding keeps the printable ASCII characters other than + and =.

Functions

decode_pair

Decodes two hexadecimal digits (either case) into a byte.