82 lines
1.7 KiB
Java
82 lines
1.7 KiB
Java
package org.antlr.v4.runtime;
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import org.antlr.v4.runtime.misc.Interval;
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/**
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* This class supports case-insensitive lexing by wrapping an existing
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* {@link CharStream} and forcing the lexer to see either upper or
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* lowercase characters. Grammar literals should then be either upper or
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* lower case such as 'BEGIN' or 'begin'. The text of the character
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* stream is unaffected. Example: input 'BeGiN' would match lexer rule
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* 'BEGIN' if constructor parameter upper=true but getText() would return
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* 'BeGiN'.
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*/
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public class CaseChangingCharStream implements CharStream {
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final CharStream stream;
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final boolean upper;
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/**
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* Constructs a new CaseChangingCharStream wrapping the given {@link CharStream} forcing
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* all characters to upper case or lower case.
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* @param stream The stream to wrap.
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* @param upper If true force each symbol to upper case, otherwise force to lower.
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*/
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public CaseChangingCharStream(CharStream stream, boolean upper) {
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this.stream = stream;
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this.upper = upper;
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}
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@Override
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public String getText(Interval interval) {
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return stream.getText(interval);
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}
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@Override
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public void consume() {
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stream.consume();
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}
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@Override
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public int LA(int i) {
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int c = stream.LA(i);
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if (c <= 0) {
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return c;
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}
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if (upper) {
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return Character.toUpperCase(c);
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}
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return Character.toLowerCase(c);
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}
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@Override
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public int mark() {
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return stream.mark();
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}
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@Override
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public void release(int marker) {
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stream.release(marker);
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}
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@Override
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public int index() {
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return stream.index();
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}
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@Override
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public void seek(int index) {
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stream.seek(index);
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}
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@Override
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public int size() {
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return stream.size();
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}
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@Override
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public String getSourceName() {
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return stream.getSourceName();
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}
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}
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