Struct ServiceStringAdvice 

pub struct ServiceStringAdvice {
    pub element_sep: u8,
    pub component_sep: u8,
    pub release_char: u8,
    pub decimal_mark: u8,
    pub repetition_sep: u8,
    pub segment_term: u8,
}

EDIFACT service string advice (UNA segment).

Defaults: + (element), : (component), ? (release), . (decimal mark), * (repetition separator), ' (segment terminator).

All six service characters are first-class fields. is_valid checks all six for mutual distinctness and for being printable, non-alphanumeric ASCII, so a collision between the repetition separator and any other delimiter — or a delimiter that would clash with segment-tag characters — is caught at UNA parse time.

Fields

element_sep: u8

Data element separator (default +)

component_sep: u8

Component data element separator (default :)

release_char: u8

Release character (default ?)

decimal_mark: u8

Decimal notation mark (default .; UNA byte 5, ISO 9735-1 §7.1). Not used by the tokenizer for splitting, but preserved for downstream use.

repetition_sep: u8

Repetition separator (UNA byte 7, ISO 9735-4 §3.1).

Defaults to space (0x20), the conventional “not used” sentinel, when no UNA is present. Some DVGW gas-market profiles and other non-default EDIFACT implementations declare a real repetition separator here; this field is always populated from the UNA so that downstream code can access it without re-parsing the raw UNA bytes.

The tokenizer does not currently split on the repetition separator — that responsibility belongs to downstream consumers — but is_valid() includes it in the six-way uniqueness check to catch delimiter collisions early.

segment_term: u8

Segment terminator (default ')

Implementations

impl ServiceStringAdvice

pub fn from_bytes(input: &[u8]) -> Result<Self, EdifactError>

Parse a UNA header and validate that all six service characters (element_sep, component_sep, decimal_mark, release_char, repetition_sep, and segment_term) are mutually distinct and are printable, non-alphanumeric ASCII. See is_valid for the exact rule.

Returns EdifactError::InvalidUna if the invariant is violated. Falls back to ServiceStringAdvice::default when no UNA is present.

This is the safe, default constructor — always use this for input from an external source. For trusted or internal use where delimiter uniqueness is already guaranteed, use from_bytes_unchecked.

pub fn from_bytes_unchecked(input: &[u8]) -> Self

Parse a UNA header from the beginning of an EDIFACT interchange without validating delimiter uniqueness or printability.

If no UNA is present, returns ServiceStringAdvice::default.

The repetition_sep field is populated from UNA byte 7 (ISO 9735-4 §3.1) or defaults to space (0x20, the “not used” sentinel) when no UNA is present.

When to use

Use this only for trusted internal data (e.g. round-tripping data where the UNA invariant is already guaranteed) or in fuzz/property tests that intentionally explore degenerate delimiter combinations.

For any external or user-provided input, prefer from_bytes which validates delimiter uniqueness and rejects invalid bytes.

pub fn is_valid(&self) -> bool

Return true if all active service characters are mutually distinct and printable ASCII.

The five mandatory characters (element_sep, component_sep, decimal_mark, release_char, segment_term) must all be printable, non-alphanumeric ASCII (0x21–0x7E, excluding 0-9A-Za-z) and mutually distinct (10 pairwise checks). Alphanumerics are rejected because segment tags are written verbatim and cannot be escaped, so a letter delimiter would make tags containing it unrepresentable.

The repetition_sep field is also validated when it is not a space (0x20). A space at position 7 of the UNA is the conventional “absent” sentinel used by interchanges that do not employ repetition elements (ISO 9735-1 / ISO 9735-4 §3.1), and it is accepted without a printability or uniqueness check. Any other value must be printable non-alphanumeric ASCII and distinct from all five mandatory characters.

High bytes (>= 0x80) are rejected because they would incorrectly bisect multi-byte UTF-8 sequences, and DEL (0x7F) is a non-printable control character.

Trait Implementations

impl Clone for ServiceStringAdvice

fn clone(&self) -> ServiceStringAdvice

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for ServiceStringAdvice

impl Debug for ServiceStringAdvice

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

Formats the value using the given formatter.

impl Default for ServiceStringAdvice

fn default() -> Self

Returns the “default value” for a type.

impl Eq for ServiceStringAdvice

impl PartialEq for ServiceStringAdvice

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for ServiceStringAdvice