/*
* [The "BSD licence"]
* Copyright (c) 2005-2008 Terence Parr
* All rights reserved.
*
* Conversion to C#:
* Copyright (c) 2008-2009 Sam Harwell, Pixel Mine, Inc.
* 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.
*/
// #define TRACK_POSITION
namespace Antlr.Runtime
{
using System.Collections.Generic;
/** <summary>
* A pretty quick CharStream that pulls all data from an array
* directly. Every method call counts in the lexer. Java's
* strings aren't very good so I'm avoiding.
* </summary>
*/
[System.Serializable]
public class SlimStringStream : ICharStream
{
/** <summary>The data being scanned</summary> */
protected string data;
//protected char[] data;
/** <summary>How many characters are actually in the buffer</summary> */
protected int n;
/** <summary>0..n-1 index into string of next char</summary> */
protected int p = 0;
#if TRACK_POSITION
/** <summary>line number 1..n within the input</summary> */
protected int line = 1;
/** <summary>The index of the character relative to the beginning of the line 0..n-1</summary> */
protected int charPositionInLine = 0;
#endif
/** <summary>tracks how deep mark() calls are nested</summary> */
protected int markDepth = 0;
/** <summary>
* A list of CharStreamState objects that tracks the stream state
* values line, charPositionInLine, and p that can change as you
* move through the input stream. Indexed from 1..markDepth.
* A null is kept @ index 0. Create upon first call to mark().
* </summary>
*/
protected IList<CharStreamState> markers;
/** <summary>Track the last mark() call result value for use in rewind().</summary> */
protected int lastMarker;
/** <summary>What is name or source of this char stream?</summary> */
public string name;
public SlimStringStream()
{
}
/** <summary>Copy data in string to a local char array</summary> */
public SlimStringStream( string input )
: this( input, null )
{
}
public SlimStringStream( string input, string sourceName )
: this( input.ToCharArray(), input.Length, sourceName )
{
}
/** <summary>This is the preferred constructor as no data is copied</summary> */
public SlimStringStream( char[] data, int numberOfActualCharsInArray )
: this( data, numberOfActualCharsInArray, null )
{
}
public SlimStringStream( char[] data, int numberOfActualCharsInArray, string sourceName )
: this()
{
//this.data = data;
this.data = new string( data );
this.n = numberOfActualCharsInArray;
this.name = sourceName;
}
/** <summary>
* Return the current input symbol index 0..n where n indicates the
* last symbol has been read. The index is the index of char to
* be returned from LA(1).
* </summary>
*/
public int Index
{
get
{
return p;
}
}
#if TRACK_POSITION
public int Line
{
get
{
return line;
}
set
{
line = value;
}
}
public int CharPositionInLine
{
get
{
return charPositionInLine;
}
set
{
charPositionInLine = value;
}
}
#else
public int Line
{
get
{
return -1;
}
set
{
}
}
public int CharPositionInLine
{
get
{
return -1;
}
set
{
}
}
#endif
/** <summary>
* Reset the stream so that it's in the same state it was
* when the object was created *except* the data array is not
* touched.
* </summary>
*/
public void Reset()
{
p = 0;
#if TRACK_POSITION
line = 1;
charPositionInLine = 0;
#endif
markDepth = 0;
}
public void Consume()
{
//System.out.println("prev p="+p+", c="+(char)data[p]);
if ( p < n )
{
#if TRACK_POSITION
charPositionInLine++;
if ( data[p] == '\n' )
{
/*
System.out.println("newline char found on line: "+line+
"@ pos="+charPositionInLine);
*/
line++;
charPositionInLine = 0;
}
#endif
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 CharStreamConstants.EndOfFile; // invalid; no char before first char
}
}
if ( ( p + i - 1 ) >= n )
{
//System.out.println("char LA("+i+")=EOF; p="+p);
return CharStreamConstants.EndOfFile;
}
//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 Count
{
get
{
return n;
}
}
public int Mark()
{
if ( markers == null )
{
markers = new List<CharStreamState>();
markers.Add( null ); // depth 0 means no backtracking, leave blank
}
markDepth++;
CharStreamState state = null;
if ( markDepth >= markers.Count )
{
state = new CharStreamState();
markers.Add( state );
}
else
{
state = markers[markDepth];
}
state.p = p;
#if TRACK_POSITION
state.line = line;
state.charPositionInLine = charPositionInLine;
#endif
lastMarker = markDepth;
return markDepth;
}
public void Rewind( int m )
{
CharStreamState state = markers[m];
// restore stream state
Seek( state.p );
#if TRACK_POSITION
line = state.line;
charPositionInLine = state.charPositionInLine;
#endif
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--;
}
/** <summary>
* consume() ahead until p==index; can't just set p=index as we must
* update line and charPositionInLine.
* </summary>
*/
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 length )
{
return data.Substring( start, length );
//return new string( data, start, stop - start + 1 );
}
public string SourceName
{
get
{
return name;
}
}
}
}