anyd 0.1.1

From-scratch encoding and decoding of 1D and 2D barcodes with lossless round-trip and live-video detection
Documentation 
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//! Code 16K symbol tables.
//!
//! Code 16K (BS EN 12323:2005) is built on the Code 128 character set: every data
//! symbol value `0..=106` renders as the same six-element (bar/space) width pattern
//! Code 128 uses. This table is transcribed from the Code 128 module and cross-checked
//! against the zint reference implementation (`backend/code128.h` `zint_C128Table`).
//!
//! Code 16K adds its own row framing: eight four-element start/stop delimiter patterns
//! (EN 12323 Table 3/4) and two lookup tables (Table 5) that map a row number to the
//! start and stop delimiter used, encoding the row's position in the stack.

/// The 107 Code 128 symbol patterns, indexed by symbol value `0..=106`.
///
/// Each string is a run of element widths starting with a bar; every entry sums to
/// 11 modules. Identical to the Code 128 table (values `103`/`104`/`105` are the
/// Start A/B/C patterns, reused by Code 16K for its mode/pad characters).
pub const C128_PATTERNS: [&str; 107] = [
    "212222", "222122", "222221", "121223", "121322", "131222", "122213", "122312", "132212",
    "221213", "221312", "231212", "112232", "122132", "122231", "113222", "123122", "123221",
    "223211", "221132", "221231", "213212", "223112", "312131", "311222", "321122", "321221",
    "312212", "322112", "322211", "212123", "212321", "232121", "111323", "131123", "131321",
    "112313", "132113", "132311", "211313", "231113", "231311", "112133", "112331", "132131",
    "113123", "113321", "133121", "313121", "211331", "231131", "213113", "213311", "213131",
    "311123", "311321", "331121", "312113", "312311", "332111", "314111", "221411", "431111",
    "111224", "111422", "121124", "121421", "141122", "141221", "112214", "112412", "122114",
    "122411", "142112", "142211", "241211", "221114", "413111", "241112", "134111", "111242",
    "121142", "121241", "114212", "124112", "124211", "411212", "421112", "421211", "212141",
    "214121", "412121", "111143", "111341", "131141", "114113", "114311", "411113", "411311",
    "113141", "114131", "311141", "411131", "211412", "211214", "211232", "233111",
];

/// EN 12323 Table 3/4: the eight start/stop delimiter patterns, four element widths
/// each (summing to 7 modules).
pub const START_STOP: [[u8; 4]; 8] = [
    [3, 2, 1, 1],
    [2, 2, 2, 1],
    [2, 1, 2, 2],
    [1, 4, 1, 1],
    [1, 1, 3, 2],
    [1, 2, 3, 1],
    [1, 1, 1, 4],
    [3, 1, 1, 2],
];

/// EN 12323 Table 5: row number -> index into [`START_STOP`] for the start delimiter.
pub const START_VALUES: [usize; 16] = [0, 1, 2, 3, 4, 5, 6, 7, 0, 1, 2, 3, 4, 5, 6, 7];

/// EN 12323 Table 5: row number -> index into [`START_STOP`] for the stop delimiter.
pub const STOP_VALUES: [usize; 16] = [0, 1, 2, 3, 4, 5, 6, 7, 4, 5, 6, 7, 0, 1, 2, 3];

/// Switch-to-Code-C symbol value.
pub const CODE_C: u8 = 99;
/// Switch-to-Code-B symbol value.
pub const CODE_B: u8 = 100;
/// Switch-to-Code-A symbol value.
pub const CODE_A: u8 = 101;
/// Shift symbol value (shift the next character to the other of A/B).
pub const SHIFT: u8 = 98;
/// FNC1 symbol value.
pub const FNC1: u8 = 102;
/// Pad symbol value.
pub const PAD: u8 = 103;

/// Look up the Code 128 symbol value whose pattern matches the six element widths.
pub fn value_for_widths(widths: &[u8]) -> Option<u8> {
    if widths.len() != 6 {
        return None;
    }
    let mut buf = [0u8; 6];
    for (slot, &w) in buf.iter_mut().zip(widths) {
        if !(1..=6).contains(&w) {
            return None;
        }
        *slot = b'0' + w;
    }
    let s = core::str::from_utf8(&buf).ok()?;
    C128_PATTERNS.iter().position(|p| *p == s).map(|v| v as u8)
}