feat(codes): add EAN/UPC, Code 128, Code 39, ITF and Codabar encoders

Check digits added, verified, fixed or off; canonical UPC-E zero
suppression; Code 128 sets B and C with zxing's switching rules; module
rows match zxing-cpp (Code 128 by length, the tie-breaking differs).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

1 files changed, 39 insertions, 0 deletions

diff --git a/source/codes/Itf.mc b/source/codes/Itf.mc
new file mode 100644
index 0000000..0d74c3b
--- /dev/null
+++ b/source/codes/Itf.mc
@@ -0,0 +1,39 @@
+// Author:  cirakg & claude ai
+// Summary: Interleaved 2 of 5 (ITF) encoder: digit pairs, optional mod-10 check digit, wide bars 3 modules (as zxing).
+
+import Toybox.Lang;
+
+module Itf {
+
+    // Five elements per digit, first element = bit 4, 1 = wide.
+    const PATTERNS = [0x06, 0x11, 0x09, 0x18, 0x05, 0x14, 0x0C, 0x03, 0x12, 0x0A];
+
+    function encode(text as String, withCheck as Boolean) as Codes.LinearCode or Codes.CodeError {
+        var values = Codes.digits(text);
+        if (values == null || values.size() == 0) {
+            return new Codes.CodeError("ITF takes digits only");
+        }
+        if (withCheck) {
+            values.add(Ean.checkDigit(values));
+        }
+        if (values.size() % 2 != 0) {
+            return new Codes.CodeError(withCheck
+                ? "ITF with a check digit needs an odd number of digits: add a leading 0"
+                : "ITF needs an even number of digits: add a leading 0");
+        }
+        var m = []b;
+        Codes.addRuns(m, [1, 1, 1, 1], true);
+        for (var i = 0; i < values.size(); i += 2) {
+            var bars = PATTERNS[values[i]] as Number;
+            var spaces = PATTERNS[values[i + 1]] as Number;
+            var widths = [] as Array<Number>;
+            for (var k = 4; k >= 0; k--) {
+                widths.add(((bars >> k) & 1) == 1 ? 3 : 1);
+                widths.add(((spaces >> k) & 1) == 1 ? 3 : 1);
+            }
+            Codes.addRuns(m, widths, true);
+        }
+        Codes.addRuns(m, [3, 1, 1], true);
+        return new Codes.LinearCode(m, Codes.digitsText(values));
+    }
+}