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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.Reflection;
using System.Text;
using System.IO;
using PdfSharp.Pdf;
using PdfSharp.Pdf.Advanced;
using PdfSharp.Pdf.Content.Objects;
namespace PdfSharp.Pdf.Content
{
/// <summary>
/// Provides the functionality to parse PDF content streams.
/// </summary>
internal sealed class CParser
{
PdfPage page;
CLexer lexer;
public CParser(PdfPage page)
{
this.page = page;
PdfContent content = page.Contents.CreateSingleContent();
byte[] bytes = content.Stream.Value;
this.lexer = new CLexer(bytes);
}
public CParser(byte[] content)
{
this.lexer = new CLexer(content);
}
public CSymbol Symbol
{
get { return this.lexer.Symbol; }
}
public CSequence ReadContent()
{
CSequence sequence = new CSequence();
ParseObject(sequence, CSymbol.Eof);
return sequence;
}
/// <summary>
/// Parses whatever comes until the specified stop symbol is reached.
/// </summary>
void ParseObject(CSequence sequence, CSymbol stop)
{
CSymbol symbol;
while ((symbol = ScanNextToken()) != CSymbol.Eof)
{
if (symbol == stop)
return;
switch (symbol)
{
case CSymbol.Comment:
// ignore comments
break;
case CSymbol.Integer:
CInteger n = new CInteger();
n.Value = this.lexer.TokenToInteger;
this.operands.Add(n);
break;
case CSymbol.Real:
CReal r = new CReal();
r.Value = this.lexer.TokenToReal;
this.operands.Add(r);
break;
case CSymbol.String:
case CSymbol.HexString:
case CSymbol.UnicodeString:
case CSymbol.UnicodeHexString:
CString s = new CString();
s.Value = this.lexer.Token;
this.operands.Add(s);
break;
case CSymbol.Name:
CName name = new CName();
name.Name = this.lexer.Token;
this.operands.Add(name);
break;
case CSymbol.Operator:
COperator op = CreateOperator();
this.operands.Clear();
sequence.Add(op);
break;
case CSymbol.BeginArray:
CArray array = new CArray();
Debug.Assert(this.operands.Count == 0, "Array within array...");
ParseObject(array, CSymbol.EndArray);
array.Add(this.operands);
this.operands.Clear();
this.operands.Add((CObject)array);
break;
case CSymbol.EndArray:
throw new ContentReaderException("Unexpected: ']'");
}
}
}
COperator CreateOperator()
{
string name = this.lexer.Token;
COperator op = OpCodes.OperatorFromName(name);
#if DEBUG
if (op.OpCode.Operands != -1 && op.OpCode.Operands != this.operands.Count)
Debug.Assert(false, "Invalid number of operands.");
#endif
op.Operands.Add(this.operands);
return op;
}
CSymbol ScanNextToken()
{
return this.lexer.ScanNextToken();
}
CSymbol ScanNextToken(out string token)
{
CSymbol symbol = this.lexer.ScanNextToken();
token = this.lexer.Token;
return symbol;
}
/// <summary>
/// Reads the next symbol that must be the specified one.
/// </summary>
CSymbol ReadSymbol(CSymbol symbol)
{
CSymbol current = this.lexer.ScanNextToken();
if (symbol != current)
throw new ContentReaderException(PSSR.UnexpectedToken(this.lexer.Token));
return current;
}
CSequence operands = new CSequence();
}
}
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