// Returns a new list of segments based on the given text and modes, such that
// consecutive code points in the same mode are put into the same segment.
private static List <QrSegment> SplitIntoSegments(int[] codePoints,
QrSegment.Mode[] charModes)
{
if (codePoints.Length == 0)
{
throw new ArgumentOutOfRangeException((codePoints.GetType().Name));
}
List <QrSegment> result = new List <QrSegment>();
// Accumulate run of modes
QrSegment.Mode curMode = charModes[0];
int start = 0;
for (int i = 1;; i++)
{
if (i < codePoints.Length && charModes[i] == curMode)
{
continue;
}
string s = FromCodePoints(codePoints, start, i - start);
if (curMode == QrSegment.Mode.Byte)
{
result.Add(QrSegment.MakeBytes(Encoding.UTF8.GetBytes(s)));
}
else if (curMode == QrSegment.Mode.Numeric)
{
result.Add(QrSegment.MakeNumeric(s));
}
else if (curMode == QrSegment.Mode.Alphanumeric)
{
result.Add(QrSegment.MakeAlphanumeric(s));
}
else if (curMode == QrSegment.Mode.Kanji)
{
result.Add(MakeKanji(s));
}
else
{
Debug.Assert(false);
}
if (i >= codePoints.Length)
{
return(result);
}
curMode = charModes[i];
start = i;
}
}
/// <summary>
/// Creates a list of zero or more segments to represent the specified text string.
/// The resulting list optimally minimizes the total encoded bit length, subjected to the constraints
/// of the specified error correction level, minimum and maximum version number.
/// <para>
/// This function potentially uses all four text encoding modes: numeric, alphanumeric, byte (UTF-8),
/// and Kanji. It is a more sophisticated but slower replacement for <see cref="MakeSegments"/>.
/// </para>
/// <para>
/// The text to be encoded can contain the full set of Unicode characters (code points).
/// </para>
/// </summary>
/// <param name="text">The text to be encoded.</param>
/// <param name="ecl">The error correction level to use.</param>
/// <param name="minVersion">The minimum version (size) of the QR code (between 1 and 40).</param>
/// <param name="maxVersion">The maximum version (size) of the QR code (between 1 and 40).</param>
/// <returns>The created mutable list of segments encoding the specified text with a minimal bit length.</returns>
/// <exception cref="ArgumentNullException"><paramref name="text"/> or <paramref name="ecl"/> is <c>null</c>.</exception>
/// <exception cref="ArgumentOutOfRangeException">1 ≤ minVersion ≤ maxVersion ≤ 40 is violated.</exception>
/// <exception cref="DataTooLongException">The text is too long to fit into the QR code with the given encoding parameters.</exception>
public static List <QrSegment> MakeSegmentsOptimally(string text, QrCode.Ecc ecl, int minVersion, int maxVersion)
{
// Check arguments
Objects.RequireNonNull(text);
Objects.RequireNonNull(ecl);
if (minVersion < QrCode.MinVersion || minVersion > maxVersion)
{
throw new ArgumentOutOfRangeException(nameof(minVersion), "Invalid value");
}
if (maxVersion > QrCode.MaxVersion)
{
throw new ArgumentOutOfRangeException(nameof(maxVersion), "Invalid value");
}
// Iterate through version numbers, and make tentative segments
List <QrSegment> segs = null;
int[] codePoints = ToCodePoints(text);
for (int version = minVersion;; version++)
{
if (version == minVersion || version == 10 || version == 27)
{
segs = MakeSegmentsOptimally(codePoints, version);
}
Debug.Assert(segs != null);
// Check if the segments fit
int dataCapacityBits = QrCode.GetNumDataCodewords(version, ecl) * 8;
int dataUsedBits = QrSegment.GetTotalBits(segs, version);
if (dataUsedBits != -1 && dataUsedBits <= dataCapacityBits)
{
return(segs); // This version number is found to be suitable
}
if (version < maxVersion)
{
continue;
}
// All versions in the range could not fit the given text
string msg = "Segment too long";
if (dataUsedBits != -1)
{
msg = "Data length = {dataUsedBits} bits, Max capacity = {dataCapacityBits} bits";
}
throw new DataTooLongException(msg);
}
}