/// <summary> Append length info. On success, store the result in "bits".</summary>
internal static void appendLengthInfo(int numLetters, int version, Mode mode, BitVector bits)
{
int numBits = mode.getCharacterCountBits(Version.getVersionForNumber(version));
if (numLetters > ((1 << numBits) - 1))
{
throw new WriterException(numLetters + "is bigger than" + ((1 << numBits) - 1));
}
bits.appendBits(numLetters, numBits);
}
/// <summary> Initialize "qrCode" according to "numInputBytes", "ecLevel", and "mode". On success,
/// modify "qrCode".
/// </summary>
private static void InitQrCode(int numInputBytes, ErrorCorrectionLevel ecLevel, Mode mode, QRCode qrCode)
{
qrCode.ECLevel = ecLevel;
qrCode.Mode = mode;
// In the following comments, we use numbers of Version 7-H.
for (int versionNum = 1; versionNum <= 40; versionNum++)
{
Version version = Version.getVersionForNumber(versionNum);
// numBytes = 196
int numBytes = version.TotalCodewords;
// getNumECBytes = 130
Version.ECBlocks ecBlocks = version.getECBlocksForLevel(ecLevel);
int numEcBytes = ecBlocks.TotalECCodewords;
// getNumRSBlocks = 5
int numRSBlocks = ecBlocks.NumBlocks;
// getNumDataBytes = 196 - 130 = 66
int numDataBytes = numBytes - numEcBytes;
// We want to choose the smallest version which can contain data of "numInputBytes" + some
// extra bits for the header (mode info and length info). The header can be three bytes
// (precisely 4 + 16 bits) at most. Hence we do +3 here.
if (numDataBytes >= numInputBytes + 3)
{
// Yay, we found the proper rs block info!
qrCode.Version = versionNum;
qrCode.NumTotalBytes = numBytes;
qrCode.NumDataBytes = numDataBytes;
qrCode.NumRSBlocks = numRSBlocks;
// getNumECBytes = 196 - 66 = 130
qrCode.NumECBytes = numEcBytes;
// matrix width = 21 + 6 * 4 = 45
qrCode.MatrixWidth = version.DimensionForVersion;
return;
}
}
throw new WriterException("Cannot find proper rs block info (input data too big?)");
}