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#region PDFsharp - A .NET library for processing PDF
//
// Authors:
// Stefan Lange (mailto:Stefan.Lange@pdfsharp.com)
//
// Copyright (c) 2005-2008 empira Software GmbH, Cologne (Germany)
//
// http://www.pdfsharp.com
// http://sourceforge.net/projects/pdfsharp
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
#endregion
using System;
using System.Diagnostics;
using System.Collections;
using System.Text;
using System.IO;
using PdfSharp.Pdf;
namespace PdfSharp.Pdf.IO
{
/// <summary>
/// Represents the stack for the shift-reduce parser. It seems that it is only neede for
/// reduction of indirect references.
/// </summary>
internal class ShiftStack
{
// TODO: make Lexer.PeekChars(20) and scan for 'R' to detect indirect references
public ShiftStack()
{
this.items = new ArrayList();
}
public PdfItem[] ToArray(int start, int length)
{
PdfItem[] items = new PdfItem[length];
for (int i = 0, j = start; i < length; i++, j++)
items[i] = (PdfItem)this.items[j];
return items;
}
/// <summary>
/// Gets the stack pointer index.
/// </summary>
public int SP
{
get {return this.sp;}
}
/// <summary>
/// Gets the value at the specifed index. Valid index is in range 0 up to sp-1.
/// </summary>
public PdfItem this[int index]
{
get
{
if (index >= this.sp)
throw new ArgumentOutOfRangeException("index", index, "Value greater than stack index.");
return (PdfItem)this.items[index];
}
}
/// <summary>
/// Gets an item relative to the current stack pointer. The index must be a negative value (-1, -2, etc.).
/// </summary>
public PdfItem GetItem(int relativeIndex)
{
if (relativeIndex >= 0 || -relativeIndex > this.sp)
throw new ArgumentOutOfRangeException("index", relativeIndex, "Value out of stack range.");
return (PdfItem)this.items[this.sp + relativeIndex];
}
/// <summary>
/// Gets an item relative to the current stack pointer. The index must be a negative value (-1, -2, etc.).
/// </summary>
public int GetInteger(int relativeIndex)
{
if (relativeIndex >= 0 || -relativeIndex > this.sp)
throw new ArgumentOutOfRangeException("index", relativeIndex, "Value out of stack range.");
return ((PdfInteger)this.items[this.sp + relativeIndex]).Value;
}
/// <summary>
/// Pushs the specified item onto the stack.
/// </summary>
public void Shift(PdfItem item)
{
Debug.Assert(item != null);
this.items.Add(item);
this.sp++;
}
/// <summary>
/// Replaces the last 'count' items with the specified item.
/// </summary>
public void Reduce(int count)
{
if (count > this.sp)
throw new ArgumentException("count causes stack underflow.");
this.items.RemoveRange(this.sp - count, count);
this.sp -= count;
}
/// <summary>
/// Replaces the last 'count' items with the specified item.
/// </summary>
public void Reduce(PdfItem item, int count)
{
Debug.Assert(item != null);
Reduce(count);
this.items.Add(item);
this.sp++;
}
/// <summary>
/// The stack pointer index. Points to the next free item.
/// </summary>
int sp;
/// <summary>
/// An array representing the stack.
/// </summary>
ArrayList items;
}
}
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