/// <summary>
/// Use to recognise which mode and encoding name to use for input string.
/// </summary>
/// <param name="content">输入字符串内容（二维码内容）</param>
/// <param name="encodingName">Output encoding name</param>
/// <returns>Mode and Encoding name</returns>
public static RecognitionStruct Recognise(string content)
{
int contentLength = content.Length;
int tryEncodePos = ModeEncodeCheck.TryEncodeKanji(content, contentLength);
if (tryEncodePos == -2)
{
return(new RecognitionStruct(Mode.EightBitByte, QRCodeConstantVariable.UTF8Encoding));
}
else if (tryEncodePos == -1)
{
return(new RecognitionStruct(Mode.Kanji, QRCodeConstantVariable.DefaultEncoding));
}
tryEncodePos = ModeEncodeCheck.TryEncodeAlphaNum(content, 0, contentLength);
if (tryEncodePos == -2)
{
return(new RecognitionStruct(Mode.Numeric, QRCodeConstantVariable.DefaultEncoding));
}
else if (tryEncodePos == -1)
{
return(new RecognitionStruct(Mode.Alphanumeric, QRCodeConstantVariable.DefaultEncoding));
}
string encodingName = EightBitByteRecognision(content, tryEncodePos, contentLength);
return(new RecognitionStruct(Mode.EightBitByte, encodingName));
}
private static string EightBitByteRecognision(string content, int startPos, int contentLength)
{
if (string.IsNullOrEmpty(content))
{
throw new ArgumentNullException("content", "Input content is null or empty");
}
ECISet eciSets = new ECISet(ECISet.AppendOption.NameToValue);
Dictionary <string, int> eciSet = eciSets.GetECITable();
//we will not check for utf8 encoding.
eciSet.Remove(QRCodeConstantVariable.UTF8Encoding);
eciSet.Remove(QRCodeConstantVariable.DefaultEncoding);
int scanPos = startPos;
//default encoding as priority
scanPos = ModeEncodeCheck.TryEncodeEightBitByte(content, QRCodeConstantVariable.DefaultEncoding, scanPos, contentLength);
if (scanPos == -1)
{
return(QRCodeConstantVariable.DefaultEncoding);
}
foreach (KeyValuePair <string, int> kvp in eciSet)
{
scanPos = ModeEncodeCheck.TryEncodeEightBitByte(content, kvp.Key, scanPos, contentLength);
if (scanPos == -1)
{
return(kvp.Key);
}
}
if (scanPos == -1)
{
throw new ArgumentException("foreach Loop check give wrong result.");
}
else
{
return(QRCodeConstantVariable.UTF8Encoding);
}
}