335 lines
9.6 KiB
C#
335 lines
9.6 KiB
C#
/*
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* [The "BSD licence"]
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* Copyright (c) 2005-2008 Terence Parr
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* All rights reserved.
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*
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* Conversion to C#:
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* Copyright (c) 2008-2009 Sam Harwell, Pixel Mine, Inc.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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// #define TRACK_POSITION
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namespace Antlr.Runtime
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{
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using System.Collections.Generic;
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/** <summary>
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* A pretty quick CharStream that pulls all data from an array
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* directly. Every method call counts in the lexer. Java's
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* strings aren't very good so I'm avoiding.
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* </summary>
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*/
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[System.Serializable]
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public class SlimStringStream : ICharStream
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{
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/** <summary>The data being scanned</summary> */
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protected string data;
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//protected char[] data;
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/** <summary>How many characters are actually in the buffer</summary> */
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protected int n;
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/** <summary>0..n-1 index into string of next char</summary> */
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protected int p = 0;
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#if TRACK_POSITION
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/** <summary>line number 1..n within the input</summary> */
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protected int line = 1;
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/** <summary>The index of the character relative to the beginning of the line 0..n-1</summary> */
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protected int charPositionInLine = 0;
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#endif
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/** <summary>tracks how deep mark() calls are nested</summary> */
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protected int markDepth = 0;
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/** <summary>
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* A list of CharStreamState objects that tracks the stream state
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* values line, charPositionInLine, and p that can change as you
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* move through the input stream. Indexed from 1..markDepth.
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* A null is kept @ index 0. Create upon first call to mark().
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* </summary>
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*/
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protected IList<CharStreamState> markers;
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/** <summary>Track the last mark() call result value for use in rewind().</summary> */
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protected int lastMarker;
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/** <summary>What is name or source of this char stream?</summary> */
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public string name;
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public SlimStringStream()
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{
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}
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/** <summary>Copy data in string to a local char array</summary> */
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public SlimStringStream( string input )
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: this( input, null )
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{
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}
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public SlimStringStream( string input, string sourceName )
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: this( input.ToCharArray(), input.Length, sourceName )
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{
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}
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/** <summary>This is the preferred constructor as no data is copied</summary> */
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public SlimStringStream( char[] data, int numberOfActualCharsInArray )
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: this( data, numberOfActualCharsInArray, null )
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{
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}
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public SlimStringStream( char[] data, int numberOfActualCharsInArray, string sourceName )
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: this()
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{
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//this.data = data;
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this.data = new string( data );
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this.n = numberOfActualCharsInArray;
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this.name = sourceName;
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}
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/** <summary>
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* Return the current input symbol index 0..n where n indicates the
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* last symbol has been read. The index is the index of char to
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* be returned from LA(1).
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* </summary>
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*/
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public int Index
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{
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get
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{
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return p;
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}
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}
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#if TRACK_POSITION
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public int Line
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{
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get
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{
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return line;
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}
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set
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{
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line = value;
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}
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}
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public int CharPositionInLine
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{
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get
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{
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return charPositionInLine;
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}
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set
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{
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charPositionInLine = value;
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}
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}
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#else
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public int Line
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{
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get
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{
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return -1;
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}
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set
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{
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}
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}
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public int CharPositionInLine
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{
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get
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{
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return -1;
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}
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set
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{
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}
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}
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#endif
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/** <summary>
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* Reset the stream so that it's in the same state it was
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* when the object was created *except* the data array is not
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* touched.
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* </summary>
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*/
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public void Reset()
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{
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p = 0;
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#if TRACK_POSITION
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line = 1;
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charPositionInLine = 0;
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#endif
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markDepth = 0;
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}
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public void Consume()
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{
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//System.out.println("prev p="+p+", c="+(char)data[p]);
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if ( p < n )
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{
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#if TRACK_POSITION
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charPositionInLine++;
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if ( data[p] == '\n' )
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{
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/*
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System.out.println("newline char found on line: "+line+
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"@ pos="+charPositionInLine);
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*/
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line++;
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charPositionInLine = 0;
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}
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#endif
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p++;
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//System.out.println("p moves to "+p+" (c='"+(char)data[p]+"')");
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}
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}
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public int LA( int i )
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{
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if ( i == 0 )
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{
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return 0; // undefined
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}
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if ( i < 0 )
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{
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i++; // e.g., translate LA(-1) to use offset i=0; then data[p+0-1]
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if ( ( p + i - 1 ) < 0 )
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{
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return CharStreamConstants.EndOfFile; // invalid; no char before first char
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}
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}
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if ( ( p + i - 1 ) >= n )
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{
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//System.out.println("char LA("+i+")=EOF; p="+p);
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return CharStreamConstants.EndOfFile;
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}
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//System.out.println("char LA("+i+")="+(char)data[p+i-1]+"; p="+p);
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//System.out.println("LA("+i+"); p="+p+" n="+n+" data.length="+data.length);
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return data[p + i - 1];
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}
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public int LT( int i )
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{
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return LA( i );
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}
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public int Count
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{
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get
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{
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return n;
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}
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}
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public int Mark()
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{
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if ( markers == null )
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{
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markers = new List<CharStreamState>();
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markers.Add( null ); // depth 0 means no backtracking, leave blank
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}
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markDepth++;
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CharStreamState state = null;
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if ( markDepth >= markers.Count )
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{
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state = new CharStreamState();
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markers.Add( state );
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}
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else
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{
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state = markers[markDepth];
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}
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state.p = p;
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#if TRACK_POSITION
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state.line = line;
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state.charPositionInLine = charPositionInLine;
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#endif
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lastMarker = markDepth;
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return markDepth;
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}
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public void Rewind( int m )
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{
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CharStreamState state = markers[m];
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// restore stream state
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Seek( state.p );
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#if TRACK_POSITION
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line = state.line;
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charPositionInLine = state.charPositionInLine;
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#endif
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Release( m );
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}
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public void Rewind()
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{
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Rewind( lastMarker );
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}
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public void Release( int marker )
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{
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// unwind any other markers made after m and release m
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markDepth = marker;
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// release this marker
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markDepth--;
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}
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/** <summary>
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* consume() ahead until p==index; can't just set p=index as we must
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* update line and charPositionInLine.
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* </summary>
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*/
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public void Seek( int index )
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{
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if ( index <= p )
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{
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p = index; // just jump; don't update stream state (line, ...)
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return;
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}
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// seek forward, consume until p hits index
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while ( p < index )
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{
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Consume();
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}
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}
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public string Substring( int start, int length )
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{
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return data.Substring( start, length );
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//return new string( data, start, stop - start + 1 );
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}
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public string SourceName
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{
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get
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{
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return name;
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}
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}
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}
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}
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