/// <summary>
// This is a helper method that an app could create to find one or all available
// ids within a string.
/// </summary>
/// <param name="inputString">String that contains one or more ids</param>
/// <returns>List of individual ids found in the input string</returns>
private List <String> FindIdsInString(String inputString)
{
// List where we maintain the ids found in the input string
List <String> idList = new List <String>();
// Maintains the beginning index of the id found in the input string
int indexIdStart = -1;
// Iterate through each of the characters in the string
for (int i = 0; i < inputString.Length; i++)
{
uint codepoint = inputString[i];
// If the character is a high surrogate, then we need to read the next character to make
// sure it is a low surrogate. If we are at the last character in the input string, then
// we have an error, since a high surrogate must be matched by a low surrogate. Update
// the code point with the surrogate pair.
if (UnicodeCharacters.IsHighSurrogate(codepoint))
{
if (++i >= inputString.Length)
{
throw new ArgumentException("Bad trailing surrogate at end of string");
}
codepoint = UnicodeCharacters.GetCodepointFromSurrogatePair(inputString[i - 1], inputString[i]);
}
// Have we found an id start?
if (indexIdStart == -1)
{
if (UnicodeCharacters.IsIdStart(codepoint))
{
// We found a character that is an id start. In case we had a suplemmentary
// character (high and low surrogate), then the index needs to offset by 1.
indexIdStart = UnicodeCharacters.IsSupplementary(codepoint) ? i - 1 : i;
}
}
else if (!UnicodeCharacters.IsIdContinue(codepoint))
{
// We have not found an id continue, so the id is complete. We need to
// create the identifier string
idList.Add(inputString.Substring(indexIdStart, i - indexIdStart));
// Reset back the index start and re-examine the current code point
// in next iteration
indexIdStart = -1;
i--;
}
}
// Do we have a pending id at the end of the string?
if (indexIdStart != -1)
{
// We need to create the identifier string
idList.Add(inputString.Substring(indexIdStart));
}
// Return the list of identifiers found in the string
return(idList);
}
public static bool IsWhiteSpaceOrControl(uint c)
{
UnicodeGeneralCategory category = UnicodeCharacters.GetGeneralCategory(c);
return(category == UnicodeGeneralCategory.Control ||
category == UnicodeGeneralCategory.SpaceSeparator ||
category == UnicodeGeneralCategory.LineSeparator ||
category == UnicodeGeneralCategory.ParagraphSeparator);
}
public static bool IsInCategory(uint c, UnicodeGeneralCategory cat)
{
return(cat == UnicodeCharacters.GetGeneralCategory(c));
}
/// <summary>
// This is a helper method that an app could create to find one or all available
// ids within a string. An id begins with a character for which IsIdStart,
// and continues with characters that are IsIdContinue. Invalid sequences are ignored.
/// </summary>
/// <param name="inputString">String from which to extract ids</param>
/// <returns>List of individual ids found in the input string</returns>
private List <String> FindIdsInString(String inputString)
{
// List where we maintain the ids found in the input string
List <String> idList = new List <String>();
// Maintains the beginning index of the id found in the input string
int indexIdStart = -1;
// Iterate through each of the characters in the string
int i = 0;
while (i < inputString.Length)
{
int nextIndex;
uint codepoint = inputString[i];
if (UnicodeCharacters.IsHighSurrogate(codepoint))
{
// If the character is a high surrogate, then the next characters must be a low surrogate.
if ((i < inputString.Length) && (UnicodeCharacters.IsLowSurrogate(inputString[i + 1])))
{
// Update the code point with the surrogate pair.
codepoint = UnicodeCharacters.GetCodepointFromSurrogatePair(codepoint, inputString[i + 1]);
nextIndex = i + 2;
}
else
{
// Warning: High surrogate not followed by low surrogate.
codepoint = 0;
nextIndex = i + 1;
}
}
else
{
// Not a surrogate pair.
nextIndex = i + 1;
}
if (indexIdStart == -1)
{
// Not in an id. Have we found an id start?
if (UnicodeCharacters.IsIdStart(codepoint))
{
indexIdStart = i;
}
}
else if (!UnicodeCharacters.IsIdContinue(codepoint))
{
// We have not found an id continue, so the id is complete. We need to
// create the identifier string
idList.Add(inputString.Substring(indexIdStart, i - indexIdStart));
// Reset back the index start and re-examine the current code point
// in next iteration
indexIdStart = -1;
nextIndex = i;
}
i = nextIndex;
}
// Do we have a pending id at the end of the string?
if (indexIdStart != -1)
{
// We need to create the identifier string
idList.Add(inputString.Substring(indexIdStart, i - indexIdStart));
}
// Return the list of identifiers found in the string
return(idList);
}
