/// <summary>
/// Encode the Tag EPC URI in SGTIN scheme into tag EPC memory bank.
/// </summary>
/// <param name="reader">Reference to the reader</param>
/// <param name="tag">Reference to the singulated tag (reader-specific datum)</param>
/// <param name="uri">The Tag URI</param>
/// <returns>True if succeeded</returns>
public static bool WriteEPC(this IReaderLowLevel reader, object tag, TagEPCURI_SGTIN uri)
{
// try to encode the EPC Tag URI
// see 14.5.1, table 14-2
// algorithm: 14.3.3
byte[] res_control = new byte[4];
byte[] res = new byte[12];
res_control[0] = 0; // CRC-16
res_control[1] = 0; // CRC-16
/*
* The number of bits, N, in the EPC binary encoding determined
* in Step 2 above, divided by 16, and rounded up to the next
* higher integer if N was not a multiple of 16
*/
var nbits = 12 * 8; // full length of PC+EPC data, in bits
int nbit_value = (nbits + 15) / 16;
var UMI = true; // indicates if user memory bank is present
var XI = false; // indicates if XPC is present
var toggle = false; // indicates if bits 0x18-0x1F contain attribute bits and the remainder of EPC bank contains a binary encoded EPC
res_control[2] =
// var pc_epc_len = ((epc[2] >> 3) & 0x1F) * 2; // full length of PC+EPC data, in bytes
(byte)((nbit_value << 3)
| (UMI? 0x4 : 0)
| (XI? 0x2 : 0)
| (toggle? 0x1 : 0));
res_control[3] = 0;
//Console.WriteLine("Control: {0}", BitConverter.ToString(res_control));
// SGTIN-96
// EPC header 1 byte = 00110000 (bin)
// filter 3 bits (3 bit integer)
// partition 3 bits (3 bit integer, see below)
// GS1 Company Prefix 20-40 bits
// Item Ref 24-4 bits
// Serial 38 bits
// write the header
res[0] = 0x30;
// write the filter
res[1] = (byte)(res[1] | ((uri.Filter & 0x7) << 5));
var uri0 = uri.Identity.URI;
byte partition = 0;
var C = uri.Identity.GS1CompanyPrefix;
var D = uri.Identity.ItemRef;
// value P (partition value, 3 bits)
// value C (of M-bit width)
var Cdigits = uri.Identity.GS1CompanyPrefixLength;
// value D (of N-bit width)
var Ddigits = uri.Identity.ItemRefLength;
// NOTE: Cdigits + Ddigits must be 13
var sum = Cdigits + Ddigits;
// there's a complication
// a GTIN might be:
// - GTIN-8 (8 digits)
// - GTIN-12 (12 digits)
// - GTIN-13 (13 digits)
// - GTIN-14 (14 digits)
// first of all, how to convert GTIN-8 to GTIN-12?
// what about anything else? should we use strings instead of long integers?
/*
* see: https://www.gs1us.org/resources/standards/company-prefix
* - GS1 Company Prefix is a string of digits
* - GS1 Company Prefix Length is between 7 and 11 digits
* - GS1 Company Prefix Length provides capacity in emitting fresh GTINs
* - prefix length = 7, capacity = 100 000
* - prefix length = 8, capacity = 10 000
*
* A GS1 Company Prefix and an Item Reference Number comprise a GTIN.
*
* http://www.envioag.com/wp-content/uploads/2013/05/GTIN_070313.pdf
*/
if (Cdigits == 12 && Ddigits == 1)
{
partition = 0;
// new SGTINPartInfo() { bitsM = 40, digitsL = 12, bitsN = 4, digits = 1 },
res[1] |= (byte)((C >> 38) & 0x3);
res[2] |= (byte)((C >> 30) & 0xFF);
res[3] |= (byte)((C >> 22) & 0xFF);
res[4] |= (byte)((C >> 14) & 0xFF);
res[5] |= (byte)((C >> 6) & 0xFF);
res[6] |= (byte)(((C >> 0) & 0x3F) << 2);
res[6] |= (byte)((D >> 2) & 0x3);
res[7] |= (byte)(((D >> 0) & 0x3) << 6);
}
else if (Cdigits == 11 && Ddigits == 2)
{
// 1
return(false);
}
else if (Cdigits == 10 && Ddigits == 3)
{
partition = 2;
res[1] |= ((byte)((C >> 32) & 0x03));
res[2] |= ((byte)((C >> 24) & 0xFF));
res[3] |= ((byte)((C >> 16) & 0xFF));
res[4] |= ((byte)((C >> 8) & 0xFF));
res[5] |= ((byte)((C >> 0) & 0xFF));
res[6] |= (byte)(D >> 2);
res[7] |= (byte)(((D >> 0) & 0x03) << 6);
}
else if (Cdigits == 9 && Ddigits == 4)
{
// 3
return(false);
}
else if (Cdigits == 8 && Ddigits == 5)
{
// 4
return(false);
}
else if (Cdigits == 7 && Ddigits == 6)
{
partition = 5;
res[1] |= ((byte)((C >> 22) & 0x03));
res[2] |= ((byte)((C >> 14) & 0xFF));
res[3] |= ((byte)((C >> 6) & 0xFF));
res[4] |= ((byte)(((C >> 0) & 0x3F) << 2));
res[4] |= ((byte)((D >> 18) & 0x03));
res[5] |= ((byte)((D >> 10) & 0xFF));
res[6] |= ((byte)((D >> 2) & 0xFF));
res[7] |= ((byte)(((D >> 0) & 0x03) << 6));
}
else if (Cdigits == 6 && Ddigits == 7)
{
// 6
return(false);
}
else
{
// unknown partition
return(false);
}
res[1] = (byte)(res[1] | ((partition & 0x7) << 2));
var S = uri.Identity.SerialNr;
res[7] = (byte)(res[7] | (byte)((S >> 32) & 0x3F));
res[8] = (byte)(res[8] | (byte)((S >> 24) & 0xFF));
res[9] = (byte)(res[9] | (byte)((S >> 16) & 0xFF));
res[10] = (byte)(res[10] | (byte)((S >> 8) & 0xFF));
res[11] = (byte)(res[11] | (byte)((S >> 0) & 0xFF));
/*
* var res_hexstring = BitConverter.ToString(res);
* Console.WriteLine("result of WriteEPC: {0}", res_hexstring);
*/
if (reader.ChunkSize > 0)
{
// try writing in blocks of ChunkSize
var csize = reader.ChunkSize;
var chunk = new byte[csize];
var beg = 0;
var ofs = 4;
while (beg < res.Length)
{
Buffer.BlockCopy(res, beg, chunk, 0, csize);
if (!reader.WriteBytes(tag, 0x01, ofs, csize, chunk))
{
return(false);
}
ofs += csize;
beg += csize;
}
return(true);
}
else
{
// skip the first 4 bytes
return(reader.WriteBytes(tag, 0x01, 4, res.Length, res));
}
}
/// <summary>
/// Generate an Tag EPC URI based on a given template and the TID.
/// </summary>
/// <param name="tid">TID of the tag that the EPC is to be generated for.</param>
/// <param name="epc">Template EPC, containing all non-serial information (e.g. GS-1 company prefix, item reference, etc.)</param>
/// <param name="res">The resulting EPC</param>
/// <returns>true if succeeded</returns>
public static bool GenerateEPC(ref TID tid, ref TagEPCURI_SGTIN epc, out TagEPCURI_SGTIN res)
{
res = default(TagEPCURI_SGTIN);
var serial = tid.Serial;
if (serial == null || serial.Length == 0)
{
return(false);
}
var MCS_identifier = (tid.TMN >> 5) & 0x3F;
var MCS_product = (tid.TMN >> 3) & 0x7;
var MCS_version = tid.TMN & 0x7;
// for Higgs-3: identifier 0x10, product 0x2, version 0x2
// for Monza: identifier 0x4, product 0, version 5
// System.Windows.Forms.MessageBox.Show(
// string.Format("MCS: identifier {0:X}, product {1:X}, version {2:X}", MCS_identifier, MCS_product, MCS_version)
// );
// extract 35 least significant bits of desired serial number
// from Serial
var start = 0;
if (serial.Length == 8) // 64 bits
{
switch (tid.TMN)
{
case 0x412:
// Alien Higgs-3: 64-bits of uniqueness
// but we only want 35 bits, and since they do
// support MCS, it should be OK
if (tid.MDID == 0x3) // vendor: Alien, chip: Higgs-3
{
start = 3;
}
else
{
return(false); // untested
}
break;
default:
return(false); // untested
}
}
else if (serial.Length == 6) // 48 bits
{
switch (tid.TMN)
{
// TMN (hex) for Monza-4 chips (source: Monza Serialization, above)
case 0x100: // Monza 4D
case 0x10C: // Monza 4E
case 0x105: // Monza 4QT
// on Impinj Monza-4 chips, this gives the sought-for uniqueness
// or does it???
if (tid.MDID == 0x801) // vendor: Impinj
{
start = 0;
}
else
{
start = 1;
}
break;
case 0x412: // Alien Higgs-3? 64-bits of uniqueness
if (tid.MDID == 0x3) // vendor: Alien, chip: Higgs-3
// NOTE: still, I found two tags which have the same UTID, byte-by-byte
{
start = 1;
}
else
{
start = 1;
}
break;
default:
start = 1; // untested
break;
}
}
else if (serial.Length == 5) // 40 bits (e.g. some NXP tags)
{
start = 0;
}
else
{
return(false);
}
var newserial = 0L;
newserial |= ((long)(serial[start + 0] & 0x07) << 32);
newserial |= ((long)(serial[start + 1] & 0xFF) << 24);
newserial |= ((long)(serial[start + 2] & 0xFF) << 16);
newserial |= ((long)(serial[start + 3] & 0xFF) << 8);
newserial |= ((long)(serial[start + 4] & 0xFF) << 0);
// put the 3 bits identifying the chip vendor
int vendor = 0;
var MDID = tid.MDID & ~0x800; // remove the XTID indicator
switch (MDID)
{
case 0x003: // Alien
vendor = 0x06; // 110
break;
case 0x001: // Impinj
vendor = 0x05; // 101
break;
case 0x006: // NXP
vendor = 0x07; // 111
break;
default:
return(false); // unknown vendor, they may not support MCS!
}
newserial |= ((long)(vendor & 0x07) << 35);
Debug.WriteLine(string.Format("serial: {0}, starting at {1}, newserial: {2}", BitConverter.ToString(serial), start, newserial));
res = epc;
// C# needs some Rust-style borrowing stuff for value types!
// (or, some linear types would be even nicer, as they are simpler)
var identity = epc.Identity;
Debug.WriteLine(string.Format("identity EPC before serial assignment {0}", identity.URI));
identity.SetSerial(newserial);
res.Identity = identity;
Debug.WriteLine(string.Format("identity EPC after serial assignment {0}", identity.URI));
return(true);
}
/// <summary>
/// Decode the EPC memory bank, which is assumed to be SGTIN-192, and return the Tag URI.
/// </summary>
/// <param name="reader">Reference to the reader that is used to obtain the TID memory bank contents</param>
/// <param name="tag">Reference to the singulated tag (reader-specific datum)</param>
/// <param name="uri">The resulting Tag URI</param>
/// <returns>Success or failure</returns>
public static DecodeError ReadEPC_SGTIN(this IReaderLowLevel reader, object tag, out TagEPCURI_SGTIN uri)
{
uri = default(TagEPCURI_SGTIN);
// see also: http://www.rfidjournal.net/masterPresentations/rfid_live2012/np/traub_apr3_230_ITProf.pdf
// what about the EPC?
// bit 0x17 of EPC is the toggle
// - we need to use SGTIN-96, and encode it
// - pure identity URI (e.g. urn:epc:id:sgtin:0614141.100743.401)
// - independent of RFID, so this is what the business apps should use
// - tag URI (e.g. urn:epc:tag:sgtin-96:3.0614141.100743.401) <-- contains control info of EPC memory bank as well
// - used when reading from a tag where the control info is of interest
// - used when writing to the EPC memory bank of an RFID tag, in order to fully specify the contents to be written
// - there exists 1:1 mapping between tag URI and binary representation
// - what's the barcode equivalent?
// barcode:
// (01) 1 0614141 12345 2 (21) 401
// ^^^^ not included
// pure identity URI:
// urn:epc:id:sgtin:0614141.112345.401
// - also, need to learn how to encode SGTIN-96 to binary form and back!
//
// also, we might want to use the GS1 GIAI schema
// - http://www.gs1.org/docs/idkeys/GS1_GIAI_Executive_Summary.pdf
// - 1 2 ... n n+1 n+2 ... <= 30
// GS1 company prefix| individual asset reference
// (numeric) | (alphanumeric)
//
// what's in SGTIN? e.g. urn:epc:id:sgtin:0614141.112345.400
// urn:epc:id:sgtin:CompanyPrefix.ItemRefAndIndicator.SerialNumber
// - company prefix (assigned by GS1 to a managing entity or its delegates)
// - item ref and indicator (assigned by the managing entity to a particular object class)
// - serial number (assigned by the managing entity to an individual object)
// what's in GIAI? e.g. urn:epc:id:giai:0614141.12345400
// urn:epc:id:giai:CompanyPrefix.IndividulAssetReference
// - company prefix (assigned by GS1 to a managing entity)
// - individual asset reference (assigned uniquely by the managing entity to a specific asset)
/*
* how to assign?
*
* what's in the EPC
* - 2 bytes of CRC (we don't usually write these, right?)
* - 2 bytes: length (5 bits), UMI (1 bit), XI (1 bit), T (1 bit), attribs (8 bits)
* - length: nr of words for PC and EPC, combined
* - 2 bytes: EPC header (1 byte), filter (3 bits), partition (3 bits), GTIN (2 bits)
* - 2 bytes: GTIN
* - 2 bytes: GTIN
* - 2 bytes: GTIN (10 bits), serial (6 bits)
* - 2 bytes: serial
* - 2 bytes: serial
* 16 bytes in total
*/
// see also: http://www.rfidjournal.net/masterPresentations/rfid_live2012/np/traub_apr3_230_ITProf.pdf
// what about the EPC?
// bit 0x17 of EPC is the toggle
// - we need to use SGTIN-96, and encode it
// - pure identity URI (e.g. urn:epc:id:sgtin:0614141.100743.401)
// - independent of RFID, so this is what the business apps should use
// - tag URI (e.g. urn:epc:tag:sgtin-96:3.0614141.100743.401) <-- contains control info of EPC memory bank as well
// - used when reading from a tag where the control info is of interest
// - used when writing to the EPC memory bank of an RFID tag, in order to fully specify the contents to be written
// - there exists 1:1 mapping between tag URI and binary representation
// - what's the barcode equivalent?
// barcode:
// (01) 1 0614141 12345 2 (21) 401
// ^^^^ not included
// pure identity URI:
// urn:epc:id:sgtin:0614141.112345.401
// - also, need to learn how to encode SGTIN-96 to binary form and back!
//
// also, we might want to use the GS1 GIAI schema
// - http://www.gs1.org/docs/idkeys/GS1_GIAI_Executive_Summary.pdf
// - 1 2 ... n n+1 n+2 ... <= 30
// GS1 company prefix| individual asset reference
// (numeric) | (alphanumeric)
//
// what's in SGTIN? e.g. urn:epc:id:sgtin:0614141.112345.400
// urn:epc:id:sgtin:CompanyPrefix.ItemRefAndIndicator.SerialNumber
// - company prefix (assigned by GS1 to a managing entity or its delegates)
// - item ref and indicator (assigned by the managing entity to a particular object class)
// - serial number (assigned by the managing entity to an individual object)
// what's in GIAI? e.g. urn:epc:id:giai:0614141.12345400
// urn:epc:id:giai:CompanyPrefix.IndividulAssetReference
// - company prefix (assigned by GS1 to a managing entity)
// - individual asset reference (assigned uniquely by the managing entity to a specific asset)
/*
* how to assign?
*
* what's in the EPC
* - 2 bytes of CRC (we don't usually write these, right?)
* - 2 bytes: length (5 bits), UMI (1 bit), XI (1 bit), T (1 bit), attribs (8 bits)
* - length: nr of words for PC and EPC, combined
* - 2 bytes: EPC header (1 byte), filter (3 bits), partition (3 bits), GTIN (2 bits)
* - 2 bytes: GTIN
* - 2 bytes: GTIN
* - 2 bytes: GTIN (10 bits), serial (6 bits)
* - 2 bytes: serial
* - 2 bytes: serial
* 16 bytes in total
*/
EPC_PC pc;
var rr = ReadEPC_PC(reader, tag, out pc);
if (rr != DecodeError.None)
{
return(rr);
}
var crc16 = pc.Crc16;
var pc_epc_len = pc.PC_EPC_Length;
var UMI = pc.UMI;
var XI = pc.XI;
var toggle = pc.Toggle;
var attribs = pc.Attribs;
// read full length of EPC (12 bytes or more)
byte[] epc_payload = new byte[pc_epc_len];
{
const int chunkSize = 4;
int sizeRead = 0;
while (sizeRead < pc_epc_len)
{
byte[] chunk;
if (!reader.ReadBytes(tag, 0x01, 4 + sizeRead, chunkSize, out chunk))
{
return(DecodeError.IO);
}
Buffer.BlockCopy(chunk, 0, epc_payload, sizeRead, chunkSize);
sizeRead += chunkSize;
}
}
//var epc_payload_hex = BitConverter.ToString(epc_payload);
//System.Windows.Forms.MessageBox.Show(BitConverter.ToString(epc_payload));
// SGTIN-96
var epc_header = epc_payload[0]; // must be 0x30 if that's SGTIN-96!
if (epc_header != 0x30)
{
return(DecodeError.Invalid); // NOT SGTIN-96!
}
if (pc_epc_len < 10 /*96 bits*/)
{
return(DecodeError.Invalid); // wrong length of EPC! (see table 14.1 in EPC TDS 1.9)
}
var filter = (epc_payload[1] >> 5) & 0x7;
var partition = (epc_payload[1] >> 2) & 0x7;
// 14.4.3
var C = 0L; // company prefix
var Cdigits = 0;
var D = 0L; // indicator/item reference
var Ddigits = 0;
var S = 0L;
// Consider these M bits to be an unsigned binary integer, C.
// The value of C must be less than 10^L, where L is the value
// specified in the “GS1 Company Prefix Digits (L)” column of
// the matching partition table row.
//
// There are N bits remaining in the input bit string, where
// N is the value specified in the “Other Field Bits” column
// of the matching partition table row. Consider these N bits
// to be an unsigned binary integer, D. The value of D must be
// less than 10^K, where K is the value specified in the
// “Other Field Digits (K)” column of the matching partition
// table row. Note that if K = 0, then the value of D must be zero.
switch (partition)
{
case 0:
// new SGTINPartInfo() { bitsM = 40, digitsL = 12, bitsN = 4, digits = 1 },
C |= ((long)(epc_payload[1] & 0x3) << 38);
C |= ((long)(epc_payload[2] & 0xFF) << 30);
C |= ((long)(epc_payload[3] & 0xFF) << 22);
C |= ((long)(epc_payload[4] & 0xFF) << 14);
C |= ((long)(epc_payload[5] & 0xFF) << 6);
C |= ((long)(((epc_payload[6] >> 2) & 0x3F)) << 0);
Cdigits = 12;
if ((ulong)C >= IntPow10((byte)Cdigits))
{
return(DecodeError.Invalid); // something is wrong with it!
}
D = ((((epc_payload[6] & 0x3) << 2) | ((epc_payload[7] >> 6) & 0x3)) & 0xFF) << 0;
Ddigits = 1;
if ((ulong)D >= IntPow10((byte)1))
{
return(DecodeError.Invalid);
}
break;
/*
* case 1:
* //{1, new SGTINPartInfo() { bitsM = 37, digitsL = 11, bitsN = 7, digits = 2 }},
* C |= ((long)(epc_payload[1] & 0x03) << 35);
* C |= ((long)(epc_payload[2] & 0xFF) << 27);
* C |= ((long)(epc_payload[3] & 0xFF) << 19);
* C |= ((long)(epc_payload[4] & 0xFF) << 11);
* C |= ((long)(epc_payload[5] & 0xFF) << 3);
* C |= ((long)(((epc_payload[6] >> 5) & 0x07)) << 0);
* Cdigits = 11;
* if ((ulong)C >= IntPow10((byte)Cdigits))
* continue; // something is wrong with it!
*
* D |= ((long)(epc_payload[6] & 0x07) << 3); // 3 bits
* D |= ((((long)epc_payload[7] >> 4) & 0x0F) << 0); // 4 bits
* Ddigits = 2;
* if ((ulong)D >= IntPow10((byte)Ddigits))
* continue;
*
* break;*/
case 2:
//{2, new SGTINPartInfo() { bitsM = 34, digitsL = 10, bitsN = 10, digits = 3 }},
C |= ((long)(epc_payload[1] & 0x03) << 32);
C |= ((long)(epc_payload[2] & 0xFF) << 24);
C |= ((long)(epc_payload[3] & 0xFF) << 16);
C |= ((long)(epc_payload[4] & 0xFF) << 8);
C |= ((long)(epc_payload[5] & 0xFF) << 0);
Cdigits = 10;
if ((ulong)C >= IntPow10((byte)Cdigits))
{
return(DecodeError.Invalid); // something is wrong with it!
}
D |= ((long)epc_payload[6] << 2);
D |= ((long)((epc_payload[7] >> 6) & 0x03) << 0);
Ddigits = 3;
if ((ulong)D >= IntPow10((byte)Ddigits))
{
return(DecodeError.Invalid);
}
break;
/*
* case 3:
* // {3, new SGTINPartInfo() { bitsM = 30, digitsL = 9, bitsN = 14, digits = 4 }},
* break;
* case 4:
* // {4, new SGTINPartInfo() { bitsM = 30, digitsL = 9, bitsN = 14, digits = 4 }},
*/
case 5:
// {5, new SGTINPartInfo() { bitsM = 24, digitsL = 7, bitsN = 20, digits = 6 }},
C |= ((long)(epc_payload[1] & 0x03) << 22);
C |= ((long)(epc_payload[2] & 0xFF) << 14);
C |= ((long)(epc_payload[3] & 0xFF) << 6);
C |= ((((long)epc_payload[4] >> 2) & 0x3F) << 0);
Cdigits = 7;
if ((ulong)C >= IntPow10((byte)Cdigits))
{
return(DecodeError.Invalid); // something is wrong with it!
}
D |= ((long)(epc_payload[4] & 0x03) << 18);
D |= ((long)(epc_payload[5] & 0xFF) << 10);
D |= ((long)(epc_payload[6] & 0xFF) << 2);
D |= ((long)((epc_payload[7] >> 6) & 0x03) << 0);
Ddigits = 6;
if ((ulong)D >= IntPow10((byte)Ddigits))
{
return(DecodeError.Invalid);
}
break;
/*
* case 6:
* //{6, new SGTINPartInfo() { bitsM = 20, digitsL = 6, bitsN = 24, digits = 7}},
* C |= ((long)(epc_payload[1] & 0x03) << 18);
* C |= ((long)(epc_payload[2] & 0xFF) << 10);
* C |= ((long)(epc_payload[3] & 0xFF) << 2);
* C |= ((((long)epc_payload[4] >> 2) & 0x3F) << 0);
* Cdigits = 6;
* if ((ulong)C >= IntPow10((byte)Cdigits))
* continue; // something is wrong with it!
*
* D |= ((long)(epc_payload[4] & 0x03) << 22);
* D |= ((long)(epc_payload[5] & 0xFF) << 14);
* D |= ((long)(epc_payload[6] & 0xFF) << 6);
* D |= ((long)((epc_payload[7] >> 2) & 0x03) << 0);
* Ddigits = 7;
* if ((ulong)D >= IntPow10((byte)Ddigits))
* continue; // something is wrong with it!
* break;*/
default:
return(DecodeError.Invalid); // unable to parse this partition
}
// serial: 38 bits
// NOTE: must be less than 274,877,906,944
// 6 bits, and then some more
S |= ((long)(epc_payload[7] & 0x3F) << 32);
S |= ((long)(epc_payload[8] & 0xFF) << 24);
S |= ((long)(epc_payload[9] & 0xFF) << 16);
S |= ((long)(epc_payload[10] & 0xFF) << 8);
S |= ((long)(epc_payload[11] & 0xFF) << 0);
uri.Filter = (byte)filter;
uri.Identity = new IdentityEPCURI_SGTIN()
{
GS1CompanyPrefix = C,
ItemRef = D,
GS1CompanyPrefixLength = Cdigits,
ItemRefLength = Ddigits,
SerialNr = S
};
return(DecodeError.None);
}
