|
static private unmaskBitMatrix ( int reference, |
||
| reference | int | |
| bits | representation of QR Code bits | |
| dimension | int | dimension of QR Code, represented by bits, being unmasked |
| return | void | |
/**
* Revert the mask removal done while reading the code words. The bit matrix should revert to its original state.
*/
internal void remask()
{
if (parsedFormatInfo == null)
{
return; // We have no format information, and have no data mask
}
int dimension = bitMatrix.Height;
DataMask.unmaskBitMatrix(parsedFormatInfo.DataMask, bitMatrix, dimension);
}
/**
* Revert the mask removal done while reading the code words. The bit matrix should revert to its original state.
*/
internal void remask()
{
if (parsedFormatInfo == null)
{
return; // We have no format information, and have no data mask
}
DataMask dataMask = DataMask.forReference(parsedFormatInfo.DataMask);
int dimension = bitMatrix.Height;
dataMask.unmaskBitMatrix(bitMatrix, dimension);
}
/// <summary> <p>Reads the bits in the {@link BitMatrix} representing the finder pattern in the
/// correct order in order to reconstruct the codewords bytes contained within the
/// QR Code.</p>
///
/// </summary>
/// <returns> bytes encoded within the QR Code
/// </returns>
/// <throws> ReaderException if the exact number of bytes expected is not read </throws>
internal byte[] readCodewords()
{
FormatInformation formatInfo = readFormatInformation();
if (formatInfo == null)
{
return(null);
}
Version version = readVersion();
if (version == null)
{
return(null);
}
// Get the data mask for the format used in this QR Code. This will exclude
// some bits from reading as we wind through the bit matrix.
int dimension = bitMatrix.Height;
DataMask.unmaskBitMatrix(formatInfo.DataMask, bitMatrix, dimension);
BitMatrix functionPattern = version.buildFunctionPattern();
bool readingUp = true;
byte[] result = new byte[version.TotalCodewords];
int resultOffset = 0;
int currentByte = 0;
int bitsRead = 0;
// Read columns in pairs, from right to left
for (int j = dimension - 1; j > 0; j -= 2)
{
if (j == 6)
{
// Skip whole column with vertical alignment pattern;
// saves time and makes the other code proceed more cleanly
j--;
}
// Read alternatingly from bottom to top then top to bottom
for (int count = 0; count < dimension; count++)
{
int i = readingUp ? dimension - 1 - count : count;
for (int col = 0; col < 2; col++)
{
// Ignore bits covered by the function pattern
if (!functionPattern[j - col, i])
{
// Read a bit
bitsRead++;
currentByte <<= 1;
if (bitMatrix[j - col, i])
{
currentByte |= 1;
}
// If we've made a whole byte, save it off
if (bitsRead == 8)
{
result[resultOffset++] = (byte)currentByte;
bitsRead = 0;
currentByte = 0;
}
}
}
}
readingUp ^= true; // readingUp = !readingUp; // switch directions
}
if (resultOffset != version.TotalCodewords)
{
return(null);
}
return(result);
}