CMSCompressedData.cs :  » PDF » iTextSharp » Org » BouncyCastle » Cms » C# / CSharp Open Source

using System;
using System.IO;

using Org.BouncyCastle.Asn1;
using Org.BouncyCastle.Asn1.Cms;
using Org.BouncyCastle.Utilities.Zlib;

namespace Org.BouncyCastle.Cms{
    /**
    * containing class for an CMS Compressed Data object
    */
    public class CmsCompressedData
    {
        internal ContentInfo contentInfo;

    public CmsCompressedData(
            byte[] compressedData)
            : this(CmsUtilities.ReadContentInfo(compressedData))
        {
        }

    public CmsCompressedData(
            Stream compressedDataStream)
            : this(CmsUtilities.ReadContentInfo(compressedDataStream))
        {
        }

    public CmsCompressedData(
            ContentInfo contentInfo)
        {
            this.contentInfo = contentInfo;
        }

    /**
     * Return the uncompressed content.
     *
     * @return the uncompressed content
     * @throws CmsException if there is an exception uncompressing the data.
     */
    public byte[] GetContent()
        {
            CompressedData comData = CompressedData.GetInstance(contentInfo.Content);
            ContentInfo content = comData.EncapContentInfo;

      Asn1OctetString bytes = (Asn1OctetString) content.Content;
      ZInflaterInputStream zIn = new ZInflaterInputStream(bytes.GetOctetStream());

      try
      {
        return CmsUtilities.StreamToByteArray(zIn);
      }
      catch (IOException e)
      {
        throw new CmsException("exception reading compressed stream.", e);
      }
      finally
      {
        zIn.Close();
      }
        }

      /**
       * Return the uncompressed content, throwing an exception if the data size
       * is greater than the passed in limit. If the content is exceeded getCause()
       * on the CMSException will contain a StreamOverflowException
       *
       * @param limit maximum number of bytes to read
       * @return the content read
       * @throws CMSException if there is an exception uncompressing the data.
       */
    public byte[] GetContent(int limit)
    {
      CompressedData  comData = CompressedData.GetInstance(contentInfo.Content);
      ContentInfo     content = comData.EncapContentInfo;

      Asn1OctetString bytes = (Asn1OctetString)content.Content;

      ZInflaterInputStream zIn = new ZInflaterInputStream(new MemoryStream(bytes.GetOctets(), false));

      try
      {
        return CmsUtilities.StreamToByteArray(zIn, limit);
      }
      catch (IOException e)
      {
        throw new CmsException("exception reading compressed stream.", e);
      }
    }

    /**
     * return the ContentInfo 
     */
    public ContentInfo ContentInfo
    {
      get { return contentInfo; }
    }

    /**
        * return the ASN.1 encoded representation of this object.
        */
        public byte[] GetEncoded()
        {
      return contentInfo.GetEncoded();
        }
    }
}