/// <summary>
/// Call this method to compute the value of
/// FilterDispertionLevel, FilterFullyMatch, FilterMatchedRanges
/// </summary>
/// <param name="lowerCaseFilterString"></param>
public void FilterApply(string lowerCaseFilterString)
{
FilterMatchedRanges = new List <CharacterRange>();
FilterFullyMatch = true;
FilterDispertionLevel = 0;
if (string.IsNullOrEmpty(lowerCaseFilterString) || string.IsNullOrEmpty(DisplayText))
{
return;
}
var lcText = DisplayText.ToLower();
var textLenght = lcText.Length;
var filterLenght = lowerCaseFilterString.Length;
int pos = 0;
int posFilter = 0;
bool matching = false;
int startMatch = 0;
while (pos < textLenght)
{
// remember matching state at the beginning of the loop
bool wasMatching = matching;
// we match the current char of the filter
if (lcText[pos] == lowerCaseFilterString[posFilter])
{
if (!matching)
{
matching = true;
startMatch = pos;
}
posFilter++;
// we matched the entire filter
if (posFilter >= filterLenght)
{
FilterMatchedRanges.Add(new CharacterRange(startMatch, pos - startMatch + 1));
break;
}
}
else
{
matching = false;
// gap between match mean more penalty than finding the match later in the string
if (posFilter > 0)
{
FilterDispertionLevel += 900;
}
else
{
FilterDispertionLevel += 30;
}
}
// we stopped matching, remember matching range
if (!matching && wasMatching)
{
FilterMatchedRanges.Add(new CharacterRange(startMatch, pos - startMatch));
}
pos++;
}
// put the exact matches first
if (filterLenght != textLenght)
{
FilterDispertionLevel += 1;
}
// we reached the end of the input, if we were matching stuff, remember matching range
if (pos >= textLenght && matching)
{
FilterMatchedRanges.Add(new CharacterRange(startMatch, pos - 1 - startMatch));
}
// we didn't match the entire filter
if (posFilter < filterLenght)
{
FilterFullyMatch = false;
}
}