/// <summary>
/// Implement <see cref="IUnicodeMatcher"/>
/// </summary>
public virtual MatchDegree Matches(IReplaceable text,
int[] offset,
int limit,
bool incremental)
{
// Note (1): We process text in 16-bit code units, rather than
// 32-bit code points. This works because stand-ins are
// always in the BMP and because we are doing a literal match
// operation, which can be done 16-bits at a time.
int i;
int[] cursor = new int[] { offset[0] };
if (limit < cursor[0])
{
// Match in the reverse direction
for (i = pattern.Length - 1; i >= 0; --i)
{
char keyChar = pattern[i]; // OK; see note (1) above
IUnicodeMatcher subm = data.LookupMatcher(keyChar);
if (subm == null)
{
if (cursor[0] > limit &&
keyChar == text[cursor[0]])
{ // OK; see note (1) above
--cursor[0];
}
else
{
return(MatchDegree.Mismatch);
}
}
else
{
MatchDegree m =
subm.Matches(text, cursor, limit, incremental);
if (m != MatchDegree.Match)
{
return(m);
}
}
}
// Record the match position, but adjust for a normal
// forward start, limit, and only if a prior match does not
// exist -- we want the rightmost match.
if (matchStart < 0)
{
matchStart = cursor[0] + 1;
matchLimit = offset[0] + 1;
}
}
else
{
for (i = 0; i < pattern.Length; ++i)
{
if (incremental && cursor[0] == limit)
{
// We've reached the context limit without a mismatch and
// without completing our match.
return(MatchDegree.PartialMatch);
}
char keyChar = pattern[i]; // OK; see note (1) above
IUnicodeMatcher subm = data.LookupMatcher(keyChar);
if (subm == null)
{
// Don't need the cursor < limit check if
// incremental is true (because it's done above); do need
// it otherwise.
if (cursor[0] < limit &&
keyChar == text[cursor[0]])
{ // OK; see note (1) above
++cursor[0];
}
else
{
return(MatchDegree.Mismatch);
}
}
else
{
MatchDegree m =
subm.Matches(text, cursor, limit, incremental);
if (m != MatchDegree.Match)
{
return(m);
}
}
}
// Record the match position
matchStart = offset[0];
matchLimit = cursor[0];
}
offset[0] = cursor[0];
return(MatchDegree.Match);
}
