/Users/parrt/antlr/code/antlr/main/runtime/Java/src/org/antlr/runtime/ANTLRStringStream.java

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/*
 [The "BSD licence"]
 Copyright (c) 2005-2008 Terence Parr
 All rights reserved.

 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions
 are met:
 1. Redistributions of source code must retain the above copyright
    notice, this list of conditions and the following disclaimer.
 2. Redistributions in binary form must reproduce the above copyright
    notice, this list of conditions and the following disclaimer in the
    documentation and/or other materials provided with the distribution.
 3. The name of the author may not be used to endorse or promote products
    derived from this software without specific prior written permission.

 THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.antlr.runtime;

import java.util.ArrayList;
import java.util.List;

public class ANTLRStringStream implements CharStream {
        protected char[] data;

        protected int n;

        protected int p=0;

        protected int line = 1;

        protected int charPositionInLine = 0;

        protected int markDepth = 0;

        protected List markers;

        protected int lastMarker;

        public String name;

        public ANTLRStringStream() {
        }

        public ANTLRStringStream(String input) {
                this();
                this.data = input.toCharArray();
                this.n = input.length();
        }

        public ANTLRStringStream(char[] data, int numberOfActualCharsInArray) {
                this();
                this.data = data;
                this.n = numberOfActualCharsInArray;
        }

        public void reset() {
                p = 0;
                line = 1;
                charPositionInLine = 0;
                markDepth = 0;
        }

    public void consume() {
                //System.out.println("prev p="+p+", c="+(char)data[p]);
        if ( p < n ) {
                        charPositionInLine++;
                        if ( data[p]=='\n' ) {
                                /*
                                System.out.println("newline char found on line: "+line+
                                                                   "@ pos="+charPositionInLine);
                                */
                                line++;
                                charPositionInLine=0;
                        }
            p++;
                        //System.out.println("p moves to "+p+" (c='"+(char)data[p]+"')");
        }
    }

    public int LA(int i) {
                if ( i==0 ) {
                        return 0; // undefined
                }
                if ( i<0 ) {
                        i++; // e.g., translate LA(-1) to use offset i=0; then data[p+0-1]
                        if ( (p+i-1) < 0 ) {
                                return CharStream.EOF; // invalid; no char before first char
                        }
                }

                if ( (p+i-1) >= n ) {
            //System.out.println("char LA("+i+")=EOF; p="+p);
            return CharStream.EOF;
        }
        //System.out.println("char LA("+i+")="+(char)data[p+i-1]+"; p="+p);
                //System.out.println("LA("+i+"); p="+p+" n="+n+" data.length="+data.length);
                return data[p+i-1];
    }

        public int LT(int i) {
                return LA(i);
        }

    public int index() {
        return p;
    }

        public int size() {
                return n;
        }

        public int mark() {
        if ( markers==null ) {
            markers = new ArrayList();
            markers.add(null); // depth 0 means no backtracking, leave blank
        }
        markDepth++;
                CharStreamState state = null;
                if ( markDepth>=markers.size() ) {
                        state = new CharStreamState();
                        markers.add(state);
                }
                else {
                        state = (CharStreamState)markers.get(markDepth);
                }
                state.p = p;
                state.line = line;
                state.charPositionInLine = charPositionInLine;
                lastMarker = markDepth;
                return markDepth;
    }

    public void rewind(int m) {
                CharStreamState state = (CharStreamState)markers.get(m);
                // restore stream state
                seek(state.p);
                line = state.line;
                charPositionInLine = state.charPositionInLine;
                release(m);
        }

        public void rewind() {
                rewind(lastMarker);
        }

        public void release(int marker) {
                // unwind any other markers made after m and release m
                markDepth = marker;
                // release this marker
                markDepth--;
        }

        public void seek(int index) {
                if ( index<=p ) {
                        p = index; // just jump; don't update stream state (line, ...)
                        return;
                }
                // seek forward, consume until p hits index
                while ( p<index ) {
                        consume();
                }
        }

        public String substring(int start, int stop) {
                return new String(data,start,stop-start+1);
        }

        public int getLine() {
                return line;
        }

        public int getCharPositionInLine() {
                return charPositionInLine;
        }

        public void setLine(int line) {
                this.line = line;
        }

        public void setCharPositionInLine(int pos) {
                this.charPositionInLine = pos;
        }

        public String getSourceName() {
                return name;
        }
}

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