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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 PdfSharp.Internal;
using PdfSharp.Pdf.IO;
using PdfSharp.Pdf.Internal;
namespace PdfSharp.Pdf.Filters
{
/// <summary>
/// Reserved for future extension.
/// </summary>
public class FilterParms
{
// not yet used
}
/// <summary>
/// Base class for all stream filters
/// </summary>
public abstract class Filter
{
/// <summary>
/// When implemented in a derived class encodes the specified data.
/// </summary>
public abstract byte[] Encode(byte[] data);
/// <summary>
/// Encodes a raw string.
/// </summary>
public virtual byte[] Encode(string rawString)
{
byte[] bytes = PdfEncoders.RawEncoding.GetBytes(rawString);
bytes = Encode(bytes);
return bytes;
}
/// <summary>
/// When implemented in a derived class decodes the specified data.
/// </summary>
public abstract byte[] Decode(byte[] data, FilterParms parms);
/// <summary>
/// Decodes the specified data.
/// </summary>
public byte[] Decode(byte[] data)
{
return Decode(data, null);
}
/// <summary>
/// Decodes to a raw string.
/// </summary>
public virtual string DecodeToString(byte[] data, FilterParms parms)
{
byte[] bytes = Decode(data, parms);
string text = PdfEncoders.RawEncoding.GetString(bytes);
return text;
}
/// <summary>
/// Decodes to a raw string.
/// </summary>
public string DecodeToString(byte[] data)
{
return DecodeToString(data, null);
}
/// <summary>
/// Removes all white spaces from the data. The function assumes that the bytes are characters.
/// </summary>
protected byte[] RemoveWhiteSpace(byte[] data)
{
int count = data.Length;
int j = 0;
for (int i = 0; i < count; i++, j++)
{
switch (data[i])
{
case (byte)Chars.NUL: // 0 Null
case (byte)Chars.HT: // 9 Tab
case (byte)Chars.LF: // 10 Line feed
case (byte)Chars.FF: // 12 Form feed
case (byte)Chars.CR: // 13 Carriage return
case (byte)Chars.SP: // 32 Space
j--;
break;
default:
if (i != j)
data[j] = data[i];
break;
}
if (j < count)
{
byte[] temp = data;
data = new byte[j];
for (int idx = 0; idx < j; idx++)
data[idx] = temp[idx];
}
}
return data;
}
}
}
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