Struct Essences 

pub struct Essences<'a, const N: usize, const XML_NORMALIZED: bool = false> { /* private fields */ }

One incremental MIME grammar pass and fixed, allocation-free comparisons against known type/subtype pairs. Parameters remain syntax-checked but do not participate in this comparison. This is not full MIME-value equality.

RFC2045 §§2 and 5.1: type/subtype are case-insensitive; comments and linear whitespace separate tokens. Token fragments cannot be joined across CFWS. https://www.rfc-editor.org/rfc/rfc2045.html#section-5.1

Implementations

impl<'a, const N: usize, const XML_NORMALIZED: bool> Essences<'a, N, XML_NORMALIZED>

pub fn new(patterns: [(&'a str, &'a str); N]) -> Self

Borrows the caller’s known pairs without allocation or registration lookup. The number of pairs is a compile-time mechanism parameter.

pub fn feed<W: Work>( &mut self, bytes: impl AsRef<[u8]>, work: &W, ) -> Result<bool, MemoryError>

Admits grammar and all comparison work before consuming this fragment. A refusal leaves both syntax and comparisons unchanged.

pub fn complete(&self) -> bool

Whether the entire original input is a complete MIME value.

pub fn matches(&self, index: usize) -> Option<bool>

Compares a known pair only if the complete original grammar succeeded. None denotes an out-of-range caller index, not a missing media type.