Crate hl7v2_parser 

HL7 v2 message parser.

This crate provides parsing functionality for HL7 v2 messages, including:

• Message parsing from raw bytes
• Batch message handling (FHS/BHS/BTS/FTS)
• MLLP-framed message parsing
• Path-based field access (re-exported from hl7v2-query)

Memory Efficiency

This parser uses a “zero-allocation where possible” approach rather than true zero-copy. Parsed messages own their data via Vec<u8>, which provides:

• Safe lifetime management without complex borrow checker patterns
• Ergonomic API that doesn’t require managing input lifetimes
• Ability to modify and re-serialize messages

For memory-constrained environments or very large messages, consider using hl7v2_stream which provides an event-based streaming parser with bounded memory usage.

Example

use hl7v2_parser::parse;

let hl7 = b"MSH|^~\\&|SendingApp|SendingFac|ReceivingApp|ReceivingFac|20250128152312||ADT^A01|ABC123|P|2.5.1\rPID|1||123456^^^HOSP^MR||Doe^John\r";
let message = parse(hl7).unwrap();

assert_eq!(message.segments.len(), 2);

Functions

get

Get value at path (e.g., PID.5[1].1)

get_presence

Get presence semantics for a field at path.

parse

Parse HL7 v2 message from bytes.

parse_batch

Parse HL7 v2 batch from bytes.

parse_file_batch

Parse HL7 v2 file batch from bytes.

parse_mllp

Parse HL7 v2 message from MLLP framed bytes.