/**
* @param bitMatrix {@link com.application.food.zxing.common.BitMatrix} to parse
* @throws com.application.food.zxing.FormatException if dimension is not >= 21 and 1 mod 4
*/
BitMatrixParser(BitMatrix bitMatrix) throws FormatException {
int dimension = bitMatrix.getHeight();
if (dimension < 21 || (dimension & 0x03) != 1) {
throw FormatException.getFormatInstance();
}
this.bitMatrix = bitMatrix;
}
/**
* Reads the bits in the {@link com.application.food.zxing.common.BitMatrix} representing the
* finder pattern in the correct order in order to reconstitute the codewords bytes contained
* within the QR Code.
*
* @return bytes encoded within the QR Code
* @throws com.application.food.zxing.FormatException if the exact number of bytes expected is not
* read
*/
byte[] readCodewords() throws FormatException {
FormatInformation formatInfo = readFormatInformation();
Version version = readVersion();
// 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.
DataMask dataMask = DataMask.forReference((int) formatInfo.getDataMask());
int dimension = bitMatrix.getHeight();
dataMask.unmaskBitMatrix(bitMatrix, dimension);
BitMatrix functionPattern = version.buildFunctionPattern();
boolean readingUp = true;
byte[] result = new byte[version.getTotalCodewords()];
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.get(j - col, i)) {
// Read a bit
bitsRead++;
currentByte <<= 1;
if (bitMatrix.get(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.getTotalCodewords()) {
throw FormatException.getFormatInstance();
}
return result;
}
/**
* Reads version information from one of its two locations within the QR Code.
*
* @return {@link Version} encapsulating the QR Code's version
* @throws com.application.food.zxing.FormatException if both version information locations cannot
* be parsed as the valid encoding of version information
*/
Version readVersion() throws FormatException {
if (parsedVersion != null) {
return parsedVersion;
}
int dimension = bitMatrix.getHeight();
int provisionalVersion = (dimension - 17) >> 2;
if (provisionalVersion <= 6) {
return Version.getVersionForNumber(provisionalVersion);
}
// Read top-right version info: 3 wide by 6 tall
int versionBits = 0;
int ijMin = dimension - 11;
for (int j = 5; j >= 0; j--) {
for (int i = dimension - 9; i >= ijMin; i--) {
versionBits = copyBit(i, j, versionBits);
}
}
Version theParsedVersion = Version.decodeVersionInformation(versionBits);
if (theParsedVersion != null && theParsedVersion.getDimensionForVersion() == dimension) {
parsedVersion = theParsedVersion;
return theParsedVersion;
}
// Hmm, failed. Try bottom left: 6 wide by 3 tall
versionBits = 0;
for (int i = 5; i >= 0; i--) {
for (int j = dimension - 9; j >= ijMin; j--) {
versionBits = copyBit(i, j, versionBits);
}
}
theParsedVersion = Version.decodeVersionInformation(versionBits);
if (theParsedVersion != null && theParsedVersion.getDimensionForVersion() == dimension) {
parsedVersion = theParsedVersion;
return theParsedVersion;
}
throw FormatException.getFormatInstance();
}
/**
* Reads format information from one of its two locations within the QR Code.
*
* @return {@link FormatInformation} encapsulating the QR Code's format info
* @throws com.application.food.zxing.FormatException if both format information locations cannot
* be parsed as the valid encoding of format information
*/
FormatInformation readFormatInformation() throws FormatException {
if (parsedFormatInfo != null) {
return parsedFormatInfo;
}
// Read top-left format info bits
int formatInfoBits1 = 0;
for (int i = 0; i < 6; i++) {
formatInfoBits1 = copyBit(i, 8, formatInfoBits1);
}
// .. and skip a bit in the timing pattern ...
formatInfoBits1 = copyBit(7, 8, formatInfoBits1);
formatInfoBits1 = copyBit(8, 8, formatInfoBits1);
formatInfoBits1 = copyBit(8, 7, formatInfoBits1);
// .. and skip a bit in the timing pattern ...
for (int j = 5; j >= 0; j--) {
formatInfoBits1 = copyBit(8, j, formatInfoBits1);
}
// Read the top-right/bottom-left pattern too
int dimension = bitMatrix.getHeight();
int formatInfoBits2 = 0;
int jMin = dimension - 7;
for (int j = dimension - 1; j >= jMin; j--) {
formatInfoBits2 = copyBit(8, j, formatInfoBits2);
}
for (int i = dimension - 8; i < dimension; i++) {
formatInfoBits2 = copyBit(i, 8, formatInfoBits2);
}
parsedFormatInfo = FormatInformation.decodeFormatInformation(formatInfoBits1, formatInfoBits2);
if (parsedFormatInfo != null) {
return parsedFormatInfo;
}
throw FormatException.getFormatInstance();
}