}// ParseMessage
/// <summary>
/// Try processing the data as a DocCap/SigCap message
/// </summary>
/// <param name="d">Decoded data from USB HID channel</param>
/// <returns>true if processed as a DocCap message, false otherwise</returns>
public Boolean ParseMessage(DecodeData d)
{
if (d.CodeType == DecodeData.CodeTypes.SignatureCapture)
{
processSigCapContent(d.RawData, true);
return(true);
}
// Document Capture messages can be formatted as one of two data packets:
// - a multi-barcode (0x98) (Obsolete, decoded here for backward compatibility)
// - a ISO15434 (0xB5) (Format generated by scanner)
if (d.CodeType == (DecodeData.CodeTypes) 0x98) // BT_MULTI_BARCODE_SSI_PACKET_TYPE
{
processOldDocCapContent(d.RawData, usbBus.HID);
return(true);
}
if (d.CodeType == (DecodeData.CodeTypes) 0xB5) // BT_ISO15434 (New DocCap format)
{
processISO15434DocCap(d.RawData, usbBus.HID);
return(true);
}
return(false);
} // ParseMessage
} // processOldDocCapContent
private void processISO15434DocCap(byte[] rawData, usbBus theBus)
{
// Validate the basic message structure first
try
{
// Header: is PacketLength correct?
// Packet length does not include itself in the count
int packetLength = (rawData[0] << 24) |
(rawData[1] << 16) |
(rawData[2] << 08) |
rawData[3];
if (packetLength + 4 != rawData.Length)
{
throw new Exception("bytes received doesn't match packet length (" + (packetLength + 4) + " vs " + rawData.GetLength(0) + ")");
}
// Header: is Message Type correct ?
if (rawData[4] != MSG_EASYCAP)
{
throw new Exception("invalid MSG type. Got " + rawData[4] + " expected " + MSG_EASYCAP);
}
// ISO15434 Envelope: is message header correct?
if ((rawData[5] != '[') || (rawData[6] != ')') || (rawData[7] != '>') || (rawData[8] != ISO_RS))
{
throw new Exception("invalid MSG header");
}
// ISO15434 Envelope: is message header correct?
if (rawData[rawData.Length - 1] != ISO_EOT)
{
throw new Exception("invalid MSG trailer. Got " + rawData[rawData.Length - 1] + " expected " + ISO_EOT);
}
}
catch (Exception e)
{
throw new Exception("Bad ISO15434 envelope: " + e.Message);
}
// At this point the basic header and ISO15434 has been validated.
// Now we can extract the format envelope(s)and call the appropriate function for processing.
// We currently expect and support only two types: Bar Code and Image. We can get none or multiples of either.
try
{
ISO15434formatEnvelope anEnvelope = new ISO15434formatEnvelope(rawData, 9);
while (anEnvelope.getNext())
{
if (anEnvelope.getFileType() == "BarCode")
{
// We have extracted bar code data - send the event so it can be displayed
byte[] decRaw = new byte[anEnvelope.getDataLength() - 1];
Array.Copy(rawData, anEnvelope.getDataIndex() + 1, decRaw, 0, anEnvelope.getDataLength() - 1);
DecodeData d = new DecodeData((DecodeData.CodeTypes)(rawData[anEnvelope.getDataIndex()]), decRaw);
DocCapDecode(this, d); // fire the event
}
else
{
// Display the image, which is an specialized Signature capture format:
// byte0 = Bitmap typeof (BMP/TIFF/JPEG)
// byte1 = Signature capture type (0 = DocCap)
// byte2-5 = Size of image data
// byte6.. = image data
SsiImageTypes thisFormat;
int i = anEnvelope.getDataIndex();
int bitmapLength = (rawData[i + 2] << 24) |
(rawData[i + 3] << 16) |
(rawData[i + 4] << 08) |
rawData[i + 5];
// Verify some of the data. Not required for application, but a nice sanity check
thisFormat = (SsiImageTypes)rawData[i];
if (thisFormat.ToString().ToLower() != anEnvelope.getFileType().ToLower())
{
throw new Exception("BITMAP type mismatch between bitmap and ISO msg:" + thisFormat + " vs " + anEnvelope.getFileType());
}
if (rawData[i + 1] != 0)
{
throw new Exception("expected sigcap type of 0. Got " + rawData[i + 1]);
}
if (bitmapLength + 6 != anEnvelope.getDataLength()) // the extra six bytes are those listed above.
{
throw new Exception("length mismatch between bitmap and ISO msg:" + (bitmapLength + 6) + " vs " + anEnvelope.getDataLength());
}
// Looks OK, send the event to display the message
SendCaptureImage(rawData, anEnvelope.getDataIndex(), theBus == usbBus.HID);
}
} // while (anEnvelope.getNext())
}
catch (Exception e)
{
throw new Exception("Bad ISO15434 message: " + e.Message);
}
} // processISO15434Message
} // processSigCapContent
/// <summary>
///
/// </summary>
/// <param name="rawData"></param>
/// <param name="theBus"></param>
private void processOldDocCapContent(byte[] rawData, usbBus theBus)
{
// length of first barcode (plus its symtype leader)
int offset = (rawData[2] << 8) | rawData[3];
// starting position of the 2nd barcode content
int index = 4 + offset;
bool isValid =
// must have 2 barcodes
(rawData[0] == 2)
// second barcode must be a SigCap type (69H)
&& ((index < (rawData.Length - 3)) && (rawData[index + 3] == 0x69));
if (!isValid)
{
throw new Exception("unknown symbology type/format(legacy message)");
}
// Offset is now pointing at the beginning of the first chunk,
// Each packet has a 4 header:
// byte0 - continue? (0=last chunck)
// byte1,2 - length of packet data
// byte3 - barcode type
// The first chunk (only), has a special Sigcap header of 6 bytes:
// byte0 - FMT type (BMP,TIFF,JPEG)
// byte1 - 0 (DocCap)
// byte2-5 - image length (big endian)
// Get the total length of the image from the Sigcap header
int totalLength = (rawData[index + 6] << 24) |
(rawData[index + 7] << 16) |
(rawData[index + 8] << 08) |
rawData[index + 9];
// .. And allocate a memory stream for it, and assign the initial data,
// which starts after the 4 and 6 byte headers described above.
int chunkSt = index; // Chunk start
int chunkLen = ((rawData[chunkSt + 1] << 8) | rawData[chunkSt + 2]) - 1;
try
{
rawData[index + 5] = 0; // Make sure it says DocCap
MemoryStream ms = new MemoryStream();
ms.SetLength(totalLength);
ms.Write(rawData, chunkSt + 4, chunkLen);
// Point to the next chunk, which may not exist
chunkSt += (chunkLen + 4);
// Process multiple chunks, if present
while (chunkSt < rawData.Length)
{
// extract the next chunk's length and advance our offset past the header
chunkLen = ((rawData[chunkSt + 1] << 8) | rawData[chunkSt + 2]) - 1;
// append this next chunk to our memory buffer
if ((chunkSt + chunkLen) < rawData.Length)
{
ms.Write(rawData, chunkSt + 4, chunkLen);
}
// advance to (potentially) next chunk
chunkSt += (chunkLen + 4);
}
// Display the decoded image
// Looks OK, send the event to display the message
SendCaptureImage(ms.ToArray(), 0, theBus == usbBus.HID);
// Send the decoded data
byte[] decRaw = new byte[offset - 1];
Array.Copy(rawData, 5, decRaw, 0, offset - 1);
DecodeData d = new DecodeData((DecodeData.CodeTypes)(rawData[0]), decRaw);
DocCapDecode(this, d); // fire the event
}
catch
{
throw new Exception("Image conversion error (legacy message)");
}
} // processOldDocCapContent