Fix PDF417 message decoding

cocoatype · Dec 15, 2024 · 7b29f7d · 7b29f7d
1 parent 80946b5
commit 7b29f7d
Showing 1 changed file with 9 additions and 2 deletions.
diff --git a/Sources/App/PDF417MessageDecoder.swift b/Sources/App/PDF417MessageDecoder.swift
@@ -5,8 +5,15 @@ struct PDF417MessageDecoder {
     private let intConverter = IntToCodewordConverter()
     private let decoder = HumanReadableDecoder()
     func decodedMessage(from string: String) throws -> String {
-        let codewords = try string.base64Decoded().map(Int.init).map(intConverter.codeword(for:))
-        dump(codewords)
+        let bytes = try string.base64Decoded()
+        let codewords = try stride(from: bytes.startIndex, to: bytes.endIndex, by: 2)
+          .compactMap { index -> UInt16? in
+              guard index + 1 < bytes.endIndex else { return nil }
+              let networkOrder = UInt16(bytes[index]) << 8 | UInt16(bytes[index + 1])
+              return UInt16(bigEndian: networkOrder)
+          }
+          .map(Int.init)
+          .map(intConverter.codeword(for:))
         return try decoder.string(for: codewords)
     }
 }