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Diffstat (limited to 'runtime/CSharp3/Sources/Antlr3.Runtime/Misc/LookaheadStream.cs')
| -rw-r--r-- | runtime/CSharp3/Sources/Antlr3.Runtime/Misc/LookaheadStream.cs | 271 |
1 files changed, 0 insertions, 271 deletions
diff --git a/runtime/CSharp3/Sources/Antlr3.Runtime/Misc/LookaheadStream.cs b/runtime/CSharp3/Sources/Antlr3.Runtime/Misc/LookaheadStream.cs deleted file mode 100644 index 14454a8..0000000 --- a/runtime/CSharp3/Sources/Antlr3.Runtime/Misc/LookaheadStream.cs +++ /dev/null @@ -1,271 +0,0 @@ -/* - * [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. - */ - -namespace Antlr.Runtime.Misc -{ - using ArgumentException = System.ArgumentException; - using Debug = System.Diagnostics.Debug; - using InvalidOperationException = System.InvalidOperationException; - using NotSupportedException = System.NotSupportedException; - using ArgumentOutOfRangeException = System.ArgumentOutOfRangeException; - - /** <summary> - * A lookahead queue that knows how to mark/release locations in the buffer for - * backtracking purposes. Any markers force the {@link FastQueue} superclass to - * keep all elements until no more markers; then can reset to avoid growing a - * huge buffer. - * </summary> - */ - public abstract class LookaheadStream<T> - : FastQueue<T> - where T : class - { - /** Absolute token index. It's the index of the symbol about to be - * read via {@code LT(1)}. Goes from 0 to numtokens. - */ - private int _currentElementIndex = 0; - - /** - * This is the {@code LT(-1)} element for the first element in {@link #data}. - */ - private T _previousElement; - - /** Track object returned by nextElement upon end of stream; - * Return it later when they ask for LT passed end of input. - */ - T _eof = null; - - /** <summary>Track the last mark() call result value for use in rewind().</summary> */ - int _lastMarker; - - /** <summary>tracks how deep mark() calls are nested</summary> */ - int _markDepth; - - public T EndOfFile - { - get - { - return _eof; - } - protected set - { - _eof = value; - } - } - - public T PreviousElement - { - get - { - return _previousElement; - } - } - - public virtual void Reset() - { - Clear(); - _currentElementIndex = 0; - _p = 0; - _previousElement = null; - } - - /** <summary> - * Implement nextElement to supply a stream of elements to this - * lookahead buffer. Return EOF upon end of the stream we're pulling from. - * </summary> - */ - public abstract T NextElement(); - - public abstract bool IsEndOfFile(T o); - - /** <summary> - * Get and remove first element in queue; override - * {@link FastQueue#remove()}; it's the same, just checks for backtracking. - * </summary> */ - public override T Dequeue() - { - T o = this[0]; - _p++; - // have we hit end of buffer and not backtracking? - if ( _p == _data.Count && _markDepth == 0 ) - { - _previousElement = o; - // if so, it's an opportunity to start filling at index 0 again - Clear(); // size goes to 0, but retains memory - } - return o; - } - - /** <summary>Make sure we have at least one element to remove, even if EOF</summary> */ - public virtual void Consume() - { - SyncAhead(1); - Dequeue(); - _currentElementIndex++; - } - - /** <summary> - * Make sure we have 'need' elements from current position p. Last valid - * p index is data.size()-1. p+need-1 is the data index 'need' elements - * ahead. If we need 1 element, (p+1-1)==p must be < data.size(). - * </summary> - */ - protected virtual void SyncAhead( int need ) - { - int n = ( _p + need - 1 ) - _data.Count + 1; // how many more elements we need? - if ( n > 0 ) - Fill( n ); // out of elements? - } - - /** <summary>add n elements to buffer</summary> */ - public virtual void Fill( int n ) - { - for ( int i = 0; i < n; i++ ) - { - T o = NextElement(); - if ( IsEndOfFile(o) ) - _eof = o; - - _data.Add( o ); - } - } - - /** <summary>Size of entire stream is unknown; we only know buffer size from FastQueue</summary> */ - public override int Count - { - get - { - throw new System.NotSupportedException( "streams are of unknown size" ); - } - } - - public virtual T LT( int k ) - { - if ( k == 0 ) - { - return null; - } - if ( k < 0 ) - { - return LB(-k); - } - - SyncAhead( k ); - if ((_p + k - 1) > _data.Count) - return _eof; - - return this[k - 1]; - } - - public virtual int Index - { - get - { - return _currentElementIndex; - } - } - - public virtual int Mark() - { - _markDepth++; - _lastMarker = _p; // track where we are in buffer, not absolute token index - return _lastMarker; - } - - public virtual void Release( int marker ) - { - if (_markDepth == 0) - throw new InvalidOperationException(); - - _markDepth--; - } - - public virtual void Rewind( int marker ) - { - _markDepth--; - int delta = _p - marker; - _currentElementIndex -= delta; - _p = marker; - } - - public virtual void Rewind() - { - // rewind but do not release marker - int delta = _p - _lastMarker; - _currentElementIndex -= delta; - _p = _lastMarker; - } - - /** <summary> - * Seek to a 0-indexed absolute token index. Normally used to seek backwards - * in the buffer. Does not force loading of nodes. - * </summary> - * <remarks> - * To preserve backward compatibility, this method allows seeking past the - * end of the currently buffered data. In this case, the input pointer will - * be moved but the data will only actually be loaded upon the next call to - * {@link #consume} or {@link #LT} for {@code k>0}. - * </remarks> - */ - public virtual void Seek( int index ) - { - if (index < 0) - throw new ArgumentOutOfRangeException("index"); - - int delta = _currentElementIndex - index; - if (_p - delta < 0) - throw new NotSupportedException("can't seek before the beginning of this stream's buffer"); - - _p -= delta; - _currentElementIndex = index; - } - - protected virtual T LB(int k) - { - Debug.Assert(k > 0); - - int index = _p - k; - if (index == -1) - return _previousElement; - - // if k>0 then we know index < data.size(). avoid the double-check for - // performance. - if (index >= 0 /*&& index < data.size()*/) - return _data[index]; - - if (index < -1) - throw new NotSupportedException("can't look more than one token before the beginning of this stream's buffer"); - - throw new NotSupportedException("can't look past the end of this stream's buffer using LB(int)"); - } - } -} |