logistics.sscc

pub fn build_sscc(extension_digit: i64, company_prefix: &str, serial_reference: i64) -> String

fune!(logistics.sscc@^1);  // then call build_sscc(…)

use super::funejson::Value;  ← the fune runtime: the JSON value the test vectors use; fune build keeps it only where a signature takes one
use super::validation_gs1_check_digit::gs1_check_digit;  ← from validation.gs1-check-digit ^1.0.0 · built alongside by fune

/// Build an 18-digit SSCC: extension digit, GS1 company prefix, zero-padded
/// serial reference and GS1 mod-10 check digit.
///
/// # Panics
/// Panics on an extension digit outside 0-9, a prefix that is not 4 to 12
/// ASCII digits, or a serial reference that is negative or too long.
pub fn build_sscc(extension_digit: i64, company_prefix: &str, serial_reference: i64) -> String {
    if !(0..=9).contains(&extension_digit) {
        panic!("extensionDigit must be 0 to 9, received {}", extension_digit);
    }
    let len = company_prefix.len();
    if !(4..=12).contains(&len) || !company_prefix.bytes().all(|b| b.is_ascii_digit()) {
        panic!("companyPrefix must be 4 to 12 digits, received \"{}\"", company_prefix);
    }
    if serial_reference < 0 {
        panic!("serialReference must not be negative, received {}", serial_reference);
    }
    // Prefix and serial share 16 digits, so a longer prefix leaves less room.
    // Too large is an error: truncating would reuse another unit's number.
    let room = 16 - len;
    let serial = serial_reference.to_string();
    if serial.len() > room {
        panic!(
            "serialReference must fit in {} digits after a {}-digit company prefix, received {}",
            room, len, serial_reference
        );
    }
    let data = format!("{}{}{:0>width$}", extension_digit, company_prefix, serial, width = room);
    format!("{}{}", data, gs1_check_digit(&data))
}

pub fn fune_vector(args: &[Value]) -> Value {
    Value::str(&build_sscc(args[0].as_i64(), args[1].as_str(), args[2].as_i64()))
}

Install

fune build

With that line in your source, in a Rust project (language rust in fune.project), fune build resolves it and its 1 dependency, pins them in fune.lock, downloads only the Rust package of each, and builds the code above into your project’s .fune/build, one readable file per capability with a header linking back here. A crate’s build.rs runs it before every compile. Or pin a range in fune.project and build in one step:

fune add logistics.sscc

The manifest, vectors and README with only the Rust implementation. Install it without the registry with fune add ./logistics.sscc-1.1.0-rust.fune, or fetch it from a terminal with fune pull logistics.sscc@1.1.0:rust.

The whole function, every language, is one file too: logistics.sscc-1.1.0.fune, 10,910 bytes, sha256 aea2a0319e89e237e8778fea97ac8cd01600de11bd63409a4546fd35791a5e55. It installs into a project of any language.

// fune: before logistics.sscc

// fune: after logistics.sscc

// fune: replace validation.gs1-check-digit in logistics.sscc

// fune: step logistics.sscc after <n|label>

More from the author

So a 7-digit prefix leaves 9 digits of serial reference and a 10-digit prefix leaves 6. A serial reference too large for the room left is an error rather than being truncated, because a truncated serial silently re-uses another pallet's number.

## Check digit

The standard GS1 mod-10 over the 17 data digits, from `validation.gs1-check-digit` since 1.1.0 (1.0.0 repeated the arithmetic here, because `validation.gtin` only accepted GTIN lengths). The answers are the same. GS1's own example, `(00) 1 0614141 123456789 7`, is a vector, and so is the SSCC from GS1's check digit worked example, `376104250021234569`.

## What it does not do

- It returns the bare 18 digits. The label's human-readable line shows them after the application identifier as `(00) 106141411234567897`; the barcode (GS1-128) encodes `00` followed by the 18 digits. - It does not allocate serial references. GS1 asks that an SSCC is not re-used for at least a year after the unit was shipped; keeping the counter is the caller's job. - It cannot tell whether a prefix was really allocated to you.

## Source

GS1 General Specifications, the SSCC (logistic units) and check digit calculation sections, https://www.gs1.org/standards/barcodes-epcrfid-id-keys/gs1-general-specifications ; GS1 UK, "How do I create SSCCs and logistics labels?", https://www.gs1uk.org/knowledge-hub/barcodes/how-do-i-create-ssccs-and-logistics-labels

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