static bool RegionMatchesCharSequences(ICharSequence cs, int csStart,
ICharSequence seq, int start, int length, ICharEqualityComparator charEqualityComparator)
{
//general purpose implementation for CharSequences
if (csStart < 0 || length > cs.Count - csStart)
{
return(false);
}
if (start < 0 || length > seq.Count - start)
{
return(false);
}
int csIndex = csStart;
int csEnd = csIndex + length;
int stringIndex = start;
while (csIndex < csEnd)
{
char c1 = cs[csIndex++];
char c2 = seq[stringIndex++];
if (!charEqualityComparator.CharEquals(c1, c2))
{
return(false);
}
}
return(true);
}
static bool Contains(ICharSequence a, ICharSequence b, ICharEqualityComparator comparator)
{
if (a is null || b is null || (uint)a.Count < (uint)b.Count)
{
return(false);
}
if (0u >= (uint)b.Count)
{
return(true);
}
int bStart = 0;
for (int i = 0; i < a.Count; ++i)
{
if (comparator.CharEquals(b[bStart], a[i]))
{
// If b is consumed then true.
if (++bStart == b.Count)
{
return(true);
}
}
else if (a.Count - i < b.Count)
{
// If there are not enough characters left in a for b to be contained, then false.
return(false);
}
else
{
bStart = 0;
}
}
return(false);
}