/// <summary>
/// Decodes the specified detector result.
/// </summary>
/// <param name="detectorResult">The detector result.</param>
/// <returns></returns>
public DecoderResult decode(AztecDetectorResult detectorResult)
{
ddata = detectorResult;
BitMatrix matrix = detectorResult.Bits;
if (!ddata.isCompact())
{
matrix = removeDashedLines(ddata.Bits);
}
bool[] rawbits = extractBits(matrix);
if (rawbits == null)
{
return(null);
}
bool[] correctedBits = correctBits(rawbits);
if (correctedBits == null)
{
return(null);
}
String result = getEncodedData(correctedBits);
if (result == null)
{
return(null);
}
return(new DecoderResult(null, result, null, null));
}
/// <summary>
/// performs RS error correction on an array of bits
/// </summary>
/// <param name="rawbits">The rawbits.</param>
/// <returns>the corrected array</returns>
/// <exception cref="FormatException">if the input contains too many errors</exception>
private bool[] correctBits(bool[] rawbits)
{
GenericGF gf;
if (ddata.getNbLayers() <= 2)
{
codewordSize = 6;
gf = GenericGF.AZTEC_DATA_6;
}
else if (ddata.getNbLayers() <= 8)
{
codewordSize = 8;
gf = GenericGF.AZTEC_DATA_8;
}
else if (ddata.getNbLayers() <= 22)
{
codewordSize = 10;
gf = GenericGF.AZTEC_DATA_10;
}
else
{
codewordSize = 12;
gf = GenericGF.AZTEC_DATA_12;
}
int numDataCodewords = ddata.getNbDatablocks();
int numECCodewords;
int offset;
if (ddata.isCompact())
{
offset = NB_BITS_COMPACT[ddata.getNbLayers()] - numCodewords * codewordSize;
numECCodewords = NB_DATABLOCK_COMPACT[ddata.getNbLayers()] - numDataCodewords;
}
else
{
offset = NB_BITS[ddata.getNbLayers()] - numCodewords * codewordSize;
numECCodewords = NB_DATABLOCK[ddata.getNbLayers()] - numDataCodewords;
}
int[] dataWords = new int[numCodewords];
for (int i = 0; i < numCodewords; i++)
{
int flag = 1;
for (int j = 1; j <= codewordSize; j++)
{
if (rawbits[codewordSize * i + codewordSize - j + offset])
{
dataWords[i] += flag;
}
flag <<= 1;
}
//if (dataWords[i] >= flag) {
// flag++;
//}
}
var rsDecoder = new ReedSolomonDecoder(gf);
if (!rsDecoder.decode(dataWords, numECCodewords))
{
return(null);
}
offset = 0;
invertedBitCount = 0;
bool[] correctedBits = new bool[numDataCodewords * codewordSize];
for (int i = 0; i < numDataCodewords; i++)
{
bool seriesColor = false;
int seriesCount = 0;
int flag = 1 << (codewordSize - 1);
for (int j = 0; j < codewordSize; j++)
{
bool color = (dataWords[i] & flag) == flag;
if (seriesCount == codewordSize - 1)
{
if (color == seriesColor)
{
//bit must be inverted
return(null);
}
seriesColor = false;
seriesCount = 0;
offset++;
invertedBitCount++;
}
else
{
if (seriesColor == color)
{
seriesCount++;
}
else
{
seriesCount = 1;
seriesColor = color;
}
correctedBits[i * codewordSize + j - offset] = color;
}
flag = (int)((uint)flag >> 1); // flag >>>= 1;
}
}
return(correctedBits);
}