问通过AVMetadataMachineReadableCodeObject从Aztec条形码读取原始字节会产生意想不到的结果

EN

    public override void DidOutputMetadataObjects (AVCaptureMetadataOutput captureOutput, AVMetadataObject[] metadataObjects, AVCaptureConnection connection)
    {
        foreach (AVMetadataMachineReadableCodeObject metadata in metadataObjects) {
            var d1 = (metadata.ValueForKey ((NSString)"_internal"));
            var d2 = (d1.ValueForKey ((NSString)"basicDescriptor"));
            var data = (d2.ValueForKey ((NSString)"BarcodeRawData"));
            var str = data.ToString ().Trim ().Trim (new [] { '<', '>' }).Replace (" ", "");


            var bitarray = new bool[str.Length * 4];
            for (var i = 0; i < str.Length / 2; i++) {
                int value = Convert.ToInt32 (str.Substring (i * 2, 2), 16);
                bitarray [i * 8 + 0] = (value & 1) > 0;
                bitarray [i * 8 + 1] = (value & 2) > 0;
                bitarray [i * 8 + 2] = (value & 4) > 0;
                bitarray [i * 8 + 3] = (value & 8) > 0;
                bitarray [i * 8 + 4] = (value & 16) > 0;
                bitarray [i * 8 + 5] = (value & 32) > 0;
                bitarray [i * 8 + 6] = (value & 64) > 0;
                bitarray [i * 8 + 7] = (value & 128) > 0;
            }
            var pabData = encodedData (bitarray);

            parent.scanFinished (true, pabData);
        }
    }


    enum ZXAztecTable
    {
        ZXAztecTableUpper,
        ZXAztecTableBinary,
        ZXAztecTableDigit
    };

    public byte[] encodedData (bool[] bitArray)
    {
        var result = new List<byte> ();
        int endIndex = bitArray.Length;
        ZXAztecTable latchTable = ZXAztecTable.ZXAztecTableUpper; // table most recently latched to
        ZXAztecTable shiftTable = ZXAztecTable.ZXAztecTableUpper; // table to use for the next read
        int index = 0;
        while (index < endIndex) {
            if (shiftTable == ZXAztecTable.ZXAztecTableBinary) {
                if (endIndex - index < 5) {
                    break;
                }
                int length = ReadCode (bitArray, index, 5);
                index += 5;
                if (length == 0) {
                    if (endIndex - index < 11) {
                        break;
                    }

                    length = ReadCode (bitArray, index, 11) + 31;
                    index += 11;
                }
                for (int charCount = 0; charCount < length; charCount++) {
                    if (endIndex - index < 8) {
                        index = endIndex;  // Force outer loop to exit
                        break;
                    }

                    byte code = (byte)ReadCode (bitArray, index, 8);
                    result.Add (code);
                    index += 8;
                }
                // Go back to whatever mode we had been in
                shiftTable = latchTable;
            } else {
                int size = shiftTable == ZXAztecTable.ZXAztecTableDigit ? 4 : 5;
                if (endIndex - index < size) {
                    break;
                }
                ReadCode (bitArray, index, size);
                index += size;
                latchTable = shiftTable;
                shiftTable = ZXAztecTable.ZXAztecTableBinary;
            }
        }
        return result.ToArray ();
    }

    public int ReadCode (bool[] bitArray, int startIndex, int length)
    {
        int res = 0;
        for (int i = startIndex; i < startIndex + length; i++) {
            res <<= 1;
            if (bitArray [i]) {
                res |= 0x01;
            }
        }
        return res;
    }

if let object = metadataObjects[0] as? AVMetadataMachineReadableCodeObject {
    if object.type == AVMetadataObject.ObjectType.qr {
         let descriptor = object.descriptor {
             let rawBytes = descriptor.errorPayload