Enum Encoding

pub enum Encoding {
    SevenBit,
    EightBit,
    QuotedPrintable,
    Base64,
}

A possible email Content-Transfer-Encoding

Variants

SevenBit

7bit (US-ASCII)

EightBit

8bit (UTF-8)

QuotedPrintable

Quoted Printable

Base64

Base64

Implementations

impl Encoding

pub fn choose<'a>(input: impl Into<StrOrBytes<'a>>, supports_utf8: bool) -> Self

Choose the most efficient Encoding for input

Look into input and decide what encoding format could best be used to represent it.

If the SMTP server supports the SMTPUTF8 extension supports_utf8 may me set to true, otherwise false is the safest option.

Possible return values based on supports_utf8

Encoding	false	true
7bit	✅	✅
8bit	❌	✅
quoted-printable	✅	✅
base64	✅	✅

Examples

// Ascii
{
    let input = "Hello, World!";
    assert_eq!(Encoding::choose(input, false), Encoding::SevenBit);
    assert_eq!(Encoding::choose(input, true), Encoding::SevenBit);
}

// Mostly ascii + utf-8
{
    let input = "Hello, World! 📬";
    assert_eq!(Encoding::choose(input, false), Encoding::QuotedPrintable);
    assert_eq!(Encoding::choose(input, true), Encoding::EightBit);
}

// Mostly utf-8
{
    let input = "Hello! 📬📬📬📬📬📬📬📬📬📬";
    assert_eq!(Encoding::choose(input, false), Encoding::Base64);
    assert_eq!(Encoding::choose(input, true), Encoding::EightBit);
}

// Non utf-8 bytes
{
    let input = &[255, 35, 123, 190];
    assert_eq!(Encoding::choose(input, false), Encoding::Base64);
    assert_eq!(Encoding::choose(input, true), Encoding::Base64);
}

Trait Implementations

impl Clone for Encoding

fn clone(&self) -> Encoding

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Encoding

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Hash for Encoding

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for Encoding

fn eq(&self, other: &Encoding) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for Encoding

impl Eq for Encoding

impl StructuralPartialEq for Encoding