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package org.codehaus.jparsec;
import org.codehaus.jparsec.pattern.Pattern;
import org.codehaus.jparsec.pattern.Patterns;
/**
* Parses a {@link Pattern}.
*
* @author Ben Yu
*/
final class PatternScanner extends Parser<Void> {
private final String name;
private final Pattern pattern;
PatternScanner(String name, Pattern pattern) {
this.name = name;
this.pattern = pattern;
}
@Override
boolean apply(final ParseContext ctxt) {
int at = ctxt.at;
CharSequence src = ctxt.characters();
int matchLength = pattern.match(src, at, src.length());
if (matchLength < 0) {
ctxt.expected(name);
return false;
}
ctxt.next(matchLength);
ctxt.result = null;
return true;
}
@Override
public Incremental<Void> incrementally() {
return new IncrementalPatternScanner(name, pattern);
}
@Override
public String toString() {
return name;
}
private static class IncrementalPatternScanner extends Incremental<Void> {
private final String name;
private final Pattern pattern;
public IncrementalPatternScanner(String name, Pattern pattern) {
this.name = name;
this.pattern = pattern;
}
@Override
Incremental<Void> parse(ParseContext ctxt) {
CharSequence src = ctxt.characters();
Pattern derived = pattern;
for (int i = 0; i < src.length(); i++) {
derived = derived.derive(src.charAt(i));
if (derived == Patterns.ALWAYS) {
ctxt.next(i);
ctxt.result = null;
return new Done<Void>(null);
} else if (derived == Patterns.NEVER) {
return new Failed<Void>();
}
}
return new IncrementalPatternScanner(name, derived);
}
}
}