/// <summary>
/// Does a split. In the right-to-left case we reorder the
/// array to be forwards.
/// </summary>
internal static string[] Split(Regex regex, string input, int count, int startat)
{
if (count < 0)
{
throw new ArgumentOutOfRangeException(nameof(count), SR.CountTooSmall);
}
if (startat < 0 || startat > input.Length)
{
throw new ArgumentOutOfRangeException(nameof(startat), SR.BeginIndexNotNegative);
}
string[] result;
if (count == 1)
{
result = new string[1];
result[0] = input;
return(result);
}
count -= 1;
Match match = regex.Match(input, startat);
if (!match.Success)
{
result = new string[1];
result[0] = input;
return(result);
}
else
{
List <string> al = new List <string>();
if (!regex.RightToLeft)
{
int prevat = 0;
for (; ;)
{
al.Add(input.Substring(prevat, match.Index - prevat));
prevat = match.Index + match.Length;
// add all matched capture groups to the list.
for (int i = 1; i < match.Groups.Count; i++)
{
if (match.IsMatched(i))
{
al.Add(match.Groups[i].ToString());
}
}
if (--count == 0)
{
break;
}
match = match.NextMatch();
if (!match.Success)
{
break;
}
}
al.Add(input.Substring(prevat, input.Length - prevat));
}
else
{
int prevat = input.Length;
for (; ;)
{
al.Add(input.Substring(match.Index + match.Length, prevat - match.Index - match.Length));
prevat = match.Index;
// add all matched capture groups to the list.
for (int i = 1; i < match.Groups.Count; i++)
{
if (match.IsMatched(i))
{
al.Add(match.Groups[i].ToString());
}
}
if (--count == 0)
{
break;
}
match = match.NextMatch();
if (!match.Success)
{
break;
}
}
al.Add(input.Substring(0, prevat));
al.Reverse(0, al.Count);
}
return(al.ToArray());
}
}
/// <summary>
/// Replaces all occurrences of the regex in the string with the
/// replacement evaluator.
///
/// Note that the special case of no matches is handled on its own:
/// with no matches, the input string is returned unchanged.
/// The right-to-left case is split out because StringBuilder
/// doesn't handle right-to-left string building directly very well.
/// </summary>
internal static string Replace(MatchEvaluator evaluator, Regex regex,
string input, int count, int startat)
{
if (evaluator == null)
{
throw new ArgumentNullException(nameof(evaluator));
}
if (count < -1)
{
throw new ArgumentOutOfRangeException(nameof(count), SR.CountTooSmall);
}
if (startat < 0 || startat > input.Length)
{
throw new ArgumentOutOfRangeException(nameof(startat), SR.BeginIndexNotNegative);
}
if (count == 0)
{
return(input);
}
Match match = regex.Match(input, startat);
if (!match.Success)
{
return(input);
}
else
{
StringBuilder sb = new StringBuilder();
if (!regex.RightToLeft)
{
int prevat = 0;
do
{
if (match.Index != prevat)
{
sb.Append(input, prevat, match.Index - prevat);
}
prevat = match.Index + match.Length;
sb.Append(evaluator(match));
if (--count == 0)
{
break;
}
match = match.NextMatch();
} while (match.Success);
if (prevat < input.Length)
{
sb.Append(input, prevat, input.Length - prevat);
}
}
else
{
List <string> al = new List <string>();
int prevat = input.Length;
do
{
if (match.Index + match.Length != prevat)
{
al.Add(input.Substring(match.Index + match.Length, prevat - match.Index - match.Length));
}
prevat = match.Index;
al.Add(evaluator(match));
if (--count == 0)
{
break;
}
match = match.NextMatch();
} while (match.Success);
if (prevat > 0)
{
sb.Append(input, 0, prevat);
}
for (int i = al.Count - 1; i >= 0; i--)
{
sb.Append(al[i]);
}
}
return(sb.ToString());
}
}
