// Append "bits".
public void appendBitVector(BitVector bits)
{
int size = bits.size();
for (int i = 0; i < size; ++i)
{
appendBit(bits.at(i));
}
}
// Modify the bit vector by XOR'ing with "other"
public void xor(BitVector other)
{
if (sizeInBits != other.size())
{
throw new System.ArgumentException("BitVector sizes don't match");
}
int sizeInBytes = (sizeInBits + 7) >> 3;
for (int i = 0; i < sizeInBytes; ++i)
{
// The last byte could be incomplete (i.e. not have 8 bits in
// it) but there is no problem since 0 XOR 0 == 0.
array[i] ^= other.array[i];
}
}
/// <summary> Terminate bits as described in 8.4.8 and 8.4.9 of JISX0510:2004 (p.24).</summary>
internal static void terminateBits(int numDataBytes, BitVector bits)
{
int capacity = numDataBytes << 3;
if (bits.size() > capacity)
{
throw new WriterException("data bits cannot fit in the QR Code" + bits.size() + " > " + capacity);
}
// Append termination bits. See 8.4.8 of JISX0510:2004 (p.24) for details.
// TODO: srowen says we can remove this for loop, since the 4 terminator bits are optional if
// the last byte has less than 4 bits left. So it amounts to padding the last byte with zeroes
// either way.
for (int i = 0; i < 4 && bits.size() < capacity; ++i)
{
bits.appendBit(0);
}
int numBitsInLastByte = bits.size() % 8;
// If the last byte isn't 8-bit aligned, we'll add padding bits.
if (numBitsInLastByte > 0)
{
int numPaddingBits = 8 - numBitsInLastByte;
for (int i = 0; i < numPaddingBits; ++i)
{
bits.appendBit(0);
}
}
// Should be 8-bit aligned here.
if (bits.size() % 8 != 0)
{
throw new WriterException("Number of bits is not a multiple of 8");
}
// If we have more space, we'll fill the space with padding patterns defined in 8.4.9 (p.24).
int numPaddingBytes = numDataBytes - bits.sizeInBytes();
for (int i = 0; i < numPaddingBytes; ++i)
{
if (i % 2 == 0)
{
bits.appendBits(0xec, 8);
}
else
{
bits.appendBits(0x11, 8);
}
}
if (bits.size() != capacity)
{
throw new WriterException("Bits size does not equal capacity");
}
}
// Make bit vector of version information. On success, store the result in "bits" and return true.
// See 8.10 of JISX0510:2004 (p.45) for details.
public static void makeVersionInfoBits(int version, BitVector bits)
{
bits.appendBits(version, 6);
int bchCode = calculateBCHCode(version, VERSION_INFO_POLY);
bits.appendBits(bchCode, 12);
if (bits.size() != 18)
{
// Just in case.
throw new WriterException("should not happen but we got: " + bits.size());
}
}
// Make bit vector of type information. On success, store the result in "bits" and return true.
// Encode error correction level and mask pattern. See 8.9 of
// JISX0510:2004 (p.45) for details.
public static void makeTypeInfoBits(ErrorCorrectionLevel ecLevel, int maskPattern, BitVector bits)
{
if (!QRCode.isValidMaskPattern(maskPattern))
{
throw new WriterException("Invalid mask pattern");
}
int typeInfo = (ecLevel.Bits << 3) | maskPattern;
bits.appendBits(typeInfo, 5);
int bchCode = calculateBCHCode(typeInfo, TYPE_INFO_POLY);
bits.appendBits(bchCode, 10);
BitVector maskBits = new BitVector();
maskBits.appendBits(TYPE_INFO_MASK_PATTERN, 15);
bits.xor(maskBits);
if (bits.size() != 15)
{
// Just in case.
throw new WriterException("should not happen but we got: " + bits.size());
}
}
// Embed type information. On success, modify the matrix.
public static void embedTypeInfo(ErrorCorrectionLevel ecLevel, int maskPattern, ByteMatrix matrix)
{
BitVector typeInfoBits = new BitVector();
makeTypeInfoBits(ecLevel, maskPattern, typeInfoBits);
for (int i = 0; i < typeInfoBits.size(); ++i)
{
// Place bits in LSB to MSB order. LSB (least significant bit) is the last value in
// "typeInfoBits".
int bit = typeInfoBits.at(typeInfoBits.size() - 1 - i);
// Type info bits at the left top corner. See 8.9 of JISX0510:2004 (p.46).
int x1 = TYPE_INFO_COORDINATES[i][0];
int y1 = TYPE_INFO_COORDINATES[i][1];
matrix.set_Renamed(x1, y1, bit);
if (i < 8)
{
// Right top corner.
int x2 = matrix.Width - i - 1;
int y2 = 8;
matrix.set_Renamed(x2, y2, bit);
}
else
{
// Left bottom corner.
int x2 = 8;
int y2 = matrix.Height - 7 + (i - 8);
matrix.set_Renamed(x2, y2, bit);
}
}
}
// Embed "dataBits" using "getMaskPattern". On success, modify the matrix and return true.
// For debugging purposes, it skips masking process if "getMaskPattern" is -1.
// See 8.7 of JISX0510:2004 (p.38) for how to embed data bits.
public static void embedDataBits(BitVector dataBits, int maskPattern, ByteMatrix matrix)
{
int bitIndex = 0;
int direction = - 1;
// Start from the right bottom cell.
int x = matrix.Width - 1;
int y = matrix.Height - 1;
while (x > 0)
{
// Skip the vertical timing pattern.
if (x == 6)
{
x -= 1;
}
while (y >= 0 && y < matrix.Height)
{
for (int i = 0; i < 2; ++i)
{
int xx = x - i;
// Skip the cell if it's not empty.
if (!isEmpty(matrix.get_Renamed(xx, y)))
{
continue;
}
int bit;
if (bitIndex < dataBits.size())
{
bit = dataBits.at(bitIndex);
++bitIndex;
}
else
{
// Padding bit. If there is no bit left, we'll fill the left cells with 0, as described
// in 8.4.9 of JISX0510:2004 (p. 24).
bit = 0;
}
// Skip masking if mask_pattern is -1.
if (maskPattern != - 1)
{
if (MaskUtil.getDataMaskBit(maskPattern, xx, y))
{
bit ^= 0x1;
}
}
matrix.set_Renamed(xx, y, bit);
}
y += direction;
}
direction = - direction; // Reverse the direction.
y += direction;
x -= 2; // Move to the left.
}
// All bits should be consumed.
if (bitIndex != dataBits.size())
{
throw new WriterException("Not all bits consumed: " + bitIndex + '/' + dataBits.size());
}
}
