/**
* See ISO 16022:2007, 5.4.1
*/
private static bool decodeECISegment(BitSource bits, ECIStringBuilder result)
{
if (bits.available() < 8)
{
return(false);
}
int c1 = bits.readBits(8);
if (c1 <= 127)
{
return(result.AppendECI(c1 - 1));
}
return(true);
//currently we only support character set ECIs
/*} else {
* if (bits.available() < 8) {
* throw FormatException.getFormatInstance();
* }
* int c2 = bits.readBits(8);
* if (c1 >= 128 && c1 <= 191) {
* } else {
* if (bits.available() < 8) {
* throw FormatException.getFormatInstance();
* }
* int c3 = bits.readBits(8);
* }
* }*/
}
/// <summary>
/// See ISO 16022:2006, 5.2.9 and Annex B, B.2
/// </summary>
private static bool decodeBase256Segment(BitSource bits,
ECIStringBuilder result,
IList <byte[]> byteSegments)
{
// Figure out how long the Base 256 Segment is.
int codewordPosition = 1 + bits.ByteOffset; // position is 1-indexed
int d1 = unrandomize255State(bits.readBits(8), codewordPosition++);
int count;
if (d1 == 0)
{
// Read the remainder of the symbol
count = bits.available() / 8;
}
else if (d1 < 250)
{
count = d1;
}
else
{
count = 250 * (d1 - 249) + unrandomize255State(bits.readBits(8), codewordPosition++);
}
// We're seeing NegativeArraySizeException errors from users.
if (count < 0)
{
return(false);
}
byte[] bytes = new byte[count];
for (int i = 0; i < count; i++)
{
// Have seen this particular error in the wild, such as at
// http://www.bcgen.com/demo/IDAutomationStreamingDataMatrix.aspx?MODE=3&D=Fred&PFMT=3&PT=F&X=0.3&O=0&LM=0.2
if (bits.available() < 8)
{
return(false);
}
bytes[i] = (byte)unrandomize255State(bits.readBits(8), codewordPosition++);
}
byteSegments.Add(bytes);
try
{
#if (NETFX_CORE || PORTABLE || NETSTANDARD1_0 || NETSTANDARD1_1 || NETSTANDARD1_2)
result.Append(Encoding.GetEncoding(StringUtils.ISO88591).GetString(bytes, 0, bytes.Length));
#else
result.Append(Encoding.GetEncoding(StringUtils.ISO88591).GetString(bytes));
#endif
}
catch (Exception uee)
{
throw new InvalidOperationException("Platform does not support required encoding: " + uee);
}
return(true);
}
/// <summary>
/// See ISO 16022:2006, 5.2.8 and Annex C Table C.3
/// </summary>
private static bool decodeEdifactSegment(BitSource bits, ECIStringBuilder result)
{
do
{
// If there is only two or less bytes left then it will be encoded as ASCII
if (bits.available() <= 16)
{
return(true);
}
for (int i = 0; i < 4; i++)
{
int edifactValue = bits.readBits(6);
// Check for the unlatch character
if (edifactValue == 0x1F)
{
// 011111
// Read rest of byte, which should be 0, and stop
int bitsLeft = 8 - bits.BitOffset;
if (bitsLeft != 8)
{
bits.readBits(bitsLeft);
}
return(true);
}
if ((edifactValue & 0x20) == 0)
{
// no 1 in the leading (6th) bit
edifactValue |= 0x40; // Add a leading 01 to the 6 bit binary value
}
result.Append((char)edifactValue);
}
} while (bits.available() > 0);
return(true);
}
internal static DecoderResult decode(byte[] bytes)
{
BitSource bits = new BitSource(bytes);
ECIStringBuilder result = new ECIStringBuilder(100);
StringBuilder resultTrailer = new StringBuilder(0);
List <byte[]> byteSegments = new List <byte[]>(1);
Mode mode = Mode.ASCII_ENCODE;
List <int> fnc1Positions = new List <int>(); // Would be replaceable by looking directly at 'bytes', if we're sure to not having to account for multi byte values.
int symbologyModifier;
bool isECIencoded = false;
do
{
if (mode == Mode.ASCII_ENCODE)
{
if (!decodeAsciiSegment(bits, result, resultTrailer, fnc1Positions, out mode))
{
return(null);
}
}
else
{
switch (mode)
{
case Mode.C40_ENCODE:
if (!decodeC40Segment(bits, result, fnc1Positions))
{
return(null);
}
break;
case Mode.TEXT_ENCODE:
if (!decodeTextSegment(bits, result, fnc1Positions))
{
return(null);
}
break;
case Mode.ANSIX12_ENCODE:
if (!decodeAnsiX12Segment(bits, result))
{
return(null);
}
break;
case Mode.EDIFACT_ENCODE:
if (!decodeEdifactSegment(bits, result))
{
return(null);
}
break;
case Mode.BASE256_ENCODE:
if (!decodeBase256Segment(bits, result, byteSegments))
{
return(null);
}
break;
case Mode.ECI_ENCODE:
decodeECISegment(bits, result);
isECIencoded = true; // ECI detection only, atm continue decoding as ASCII
break;
default:
return(null);
}
mode = Mode.ASCII_ENCODE;
}
} while (mode != Mode.PAD_ENCODE && bits.available() > 0);
if (resultTrailer.Length > 0)
{
result.Append(resultTrailer.ToString());
}
if (isECIencoded)
{
// Examples for this numbers can be found in this documentation of a hardware barcode scanner:
// https://honeywellaidc.force.com/supportppr/s/article/List-of-barcode-symbology-AIM-Identifiers
if (fnc1Positions.Contains(0) || fnc1Positions.Contains(4))
{
symbologyModifier = 5;
}
else if (fnc1Positions.Contains(1) || fnc1Positions.Contains(5))
{
symbologyModifier = 6;
}
else
{
symbologyModifier = 4;
}
}
else
{
if (fnc1Positions.Contains(0) || fnc1Positions.Contains(4))
{
symbologyModifier = 2;
}
else if (fnc1Positions.Contains(1) || fnc1Positions.Contains(5))
{
symbologyModifier = 3;
}
else
{
symbologyModifier = 1;
}
}
return(new DecoderResult(bytes, result.ToString(), byteSegments.Count == 0 ? null : byteSegments, null, symbologyModifier));
}
/// <summary>
/// See ISO 16022:2006, 5.2.7
/// </summary>
private static bool decodeAnsiX12Segment(BitSource bits,
ECIStringBuilder result)
{
// Three ANSI X12 values are encoded in a 16-bit value as
// (1600 * C1) + (40 * C2) + C3 + 1
int[] cValues = new int[3];
do
{
// If there is only one byte left then it will be encoded as ASCII
if (bits.available() == 8)
{
return(true);
}
int firstByte = bits.readBits(8);
if (firstByte == 254)
{
// Unlatch codeword
return(true);
}
parseTwoBytes(firstByte, bits.readBits(8), cValues);
for (int i = 0; i < 3; i++)
{
int cValue = cValues[i];
switch (cValue)
{
case 0: // X12 segment terminator <CR>
result.Append('\r');
break;
case 1: // X12 segment separator *
result.Append('*');
break;
case 2: // X12 sub-element separator >
result.Append('>');
break;
case 3: // space
result.Append(' ');
break;
default:
if (cValue < 14)
{
// 0 - 9
result.Append((char)(cValue + 44));
}
else if (cValue < 40)
{
// A - Z
result.Append((char)(cValue + 51));
}
else
{
return(false);
}
break;
}
}
} while (bits.available() > 0);
return(true);
}
/// <summary>
/// See ISO 16022:2006, 5.2.6 and Annex C, Table C.2
/// </summary>
private static bool decodeTextSegment(BitSource bits, ECIStringBuilder result, List <int> fnc1positions)
{
// Three Text values are encoded in a 16-bit value as
// (1600 * C1) + (40 * C2) + C3 + 1
// TODO(bbrown): The Upper Shift with Text doesn't work in the 4 value scenario all the time
bool upperShift = false;
int[] cValues = new int[3];
int shift = 0;
do
{
// If there is only one byte left then it will be encoded as ASCII
if (bits.available() == 8)
{
return(true);
}
int firstByte = bits.readBits(8);
if (firstByte == 254)
{
// Unlatch codeword
return(true);
}
parseTwoBytes(firstByte, bits.readBits(8), cValues);
for (int i = 0; i < 3; i++)
{
int cValue = cValues[i];
switch (shift)
{
case 0:
if (cValue < 3)
{
shift = cValue + 1;
}
else if (cValue < TEXT_BASIC_SET_CHARS.Length)
{
char textChar = TEXT_BASIC_SET_CHARS[cValue];
if (upperShift)
{
result.Append((char)(textChar + 128));
upperShift = false;
}
else
{
result.Append(textChar);
}
}
else
{
return(false);
}
break;
case 1:
if (upperShift)
{
result.Append((char)(cValue + 128));
upperShift = false;
}
else
{
result.Append((char)cValue);
}
shift = 0;
break;
case 2:
// Shift 2 for Text is the same encoding as C40
if (cValue < TEXT_SHIFT2_SET_CHARS.Length)
{
char textChar = TEXT_SHIFT2_SET_CHARS[cValue];
if (upperShift)
{
result.Append((char)(textChar + 128));
upperShift = false;
}
else
{
result.Append(textChar);
}
}
else
{
switch (cValue)
{
case 27: // FNC1
fnc1positions.Add(result.Length);
result.Append((char)29); // translate as ASCII 29
break;
case 30: // Upper Shift
upperShift = true;
break;
default:
return(false);
}
}
shift = 0;
break;
case 3:
if (cValue < TEXT_SHIFT3_SET_CHARS.Length)
{
char textChar = TEXT_SHIFT3_SET_CHARS[cValue];
if (upperShift)
{
result.Append((char)(textChar + 128));
upperShift = false;
}
else
{
result.Append(textChar);
}
shift = 0;
}
else
{
return(false);
}
break;
default:
return(false);
}
}
} while (bits.available() > 0);
return(true);
}
/// <summary>
/// See ISO 16022:2006, 5.2.3 and Annex C, Table C.2
/// </summary>
private static bool decodeAsciiSegment(BitSource bits,
ECIStringBuilder result,
StringBuilder resultTrailer,
List <int> fnc1positions,
out Mode mode)
{
bool upperShift = false;
mode = Mode.ASCII_ENCODE;
do
{
int oneByte = bits.readBits(8);
if (oneByte == 0)
{
return(false);
}
else if (oneByte <= 128)
{
// ASCII data (ASCII value + 1)
if (upperShift)
{
oneByte += 128;
//upperShift = false;
}
result.Append((char)(oneByte - 1));
mode = Mode.ASCII_ENCODE;
return(true);
}
else if (oneByte == 129)
{
// Pad
mode = Mode.PAD_ENCODE;
return(true);
}
else if (oneByte <= 229)
{
// 2-digit data 00-99 (Numeric Value + 130)
int value = oneByte - 130;
if (value < 10)
{
// pad with '0' for single digit values
result.Append('0');
}
result.Append(value);
}
else
{
switch (oneByte)
{
case 230: // Latch to C40 encodation
mode = Mode.C40_ENCODE;
return(true);
case 231: // Latch to Base 256 encodation
mode = Mode.BASE256_ENCODE;
return(true);
case 232: // FNC1
fnc1positions.Add(result.Length);
result.Append((char)29); // translate as ASCII 29
break;
case 233: // Structured Append
case 234: // Reader Programming
// Ignore these symbols for now
//throw ReaderException.getInstance();
break;
case 235: // Upper Shift (shift to Extended ASCII)
upperShift = true;
break;
case 236: // 05 Macro
result.Append("[)>\u001E05\u001D");
resultTrailer.Insert(0, "\u001E\u0004");
break;
case 237: // 06 Macro
result.Append("[)>\u001E06\u001D");
resultTrailer.Insert(0, "\u001E\u0004");
break;
case 238: // Latch to ANSI X12 encodation
mode = Mode.ANSIX12_ENCODE;
return(true);
case 239: // Latch to Text encodation
mode = Mode.TEXT_ENCODE;
return(true);
case 240: // Latch to EDIFACT encodation
mode = Mode.EDIFACT_ENCODE;
return(true);
case 241: // ECI Character
mode = Mode.ECI_ENCODE;
return(true);
default:
// Not to be used in ASCII encodation
// but work around encoders that end with 254, latch back to ASCII
if (oneByte != 254 || bits.available() != 0)
{
return(false);
}
break;
}
}
} while (bits.available() > 0);
mode = Mode.ASCII_ENCODE;
return(true);
}
