Struct FieldConsumptionTracker 

pub struct FieldConsumptionTracker { /* private fields */ }

Field consumption tracker for sequential processing of duplicate fields

Purpose

Ensures that when a message contains multiple instances of the same field (e.g., multiple :50: fields), they are consumed sequentially in the order they appear in the original message. This is critical for messages like MT101 where sequence matters.

Implementation

• Tracks consumed field indices by tag
• Provides next available field value for sequential consumption
• Maintains message order integrity during field processing

Example

use swift_mt_message::parser::FieldConsumptionTracker;

let mut tracker = FieldConsumptionTracker::new();
// Field "50" has values at positions [5, 15, 25] in message
let field_values = vec![
    ("value1".to_string(), 5),
    ("value2".to_string(), 15),
    ("value3".to_string(), 25),
];
let (value1, pos1) = tracker.get_next_available("50", &field_values).unwrap();
tracker.mark_consumed("50", pos1);
let (value2, pos2) = tracker.get_next_available("50", &field_values).unwrap();
// Ensures value2 is from position 15, not 5 or 25

Implementations

impl FieldConsumptionTracker

pub fn new() -> Self

Create a new consumption tracker

pub fn mark_consumed(&mut self, tag: &str, index: usize)

Mark a field value at a specific position as consumed

pub fn get_next_available<'a>( &self, tag: &str, values: &'a [(String, usize)], ) -> Option<(&'a str, usize)>

Get the next available (unconsumed) field value for a tag

Trait Implementations

impl Clone for FieldConsumptionTracker

fn clone(&self) -> FieldConsumptionTracker

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for FieldConsumptionTracker

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

Formats the value using the given formatter.

impl Default for FieldConsumptionTracker

fn default() -> Self

Returns the “default value” for a type.