''' <summary>
''' A predicate that checks taget compression type.
''' </summary>
Public Class ResourceCompressionAnalyzer
    Inherits Vintasoft.Imaging.Processing.Analyzers.PredicateAnalyzer(Of Vintasoft.Imaging.Pdf.Tree.PdfTreeNodeBase)

    ''' <summary>
    ''' Compression types, which should be analyzed.
    ''' </summary>
    Private _compressions As Vintasoft.Imaging.Pdf.PdfCompression()



    ''' <summary>
    ''' Initializes a new instance of the <see cref="ResourceCompressionAnalyzer"/> class.
    ''' </summary>
    ''' <param name="compressions">Compression types, which should be analyzed.</param>
    Public Sub New(compressions As Vintasoft.Imaging.Pdf.PdfCompression())
        MyBase.New("PDF resource compression analyzer")
        _compressions = compressions
    End Sub



    ''' <summary>
    ''' Returns all nodes that are <see cref="Vintasoft.Imaging.Pdf.Tree.PdfResource"/>
    ''' with ZIP compression.
    ''' </summary>
    ''' <param name="document">A PDF document.</param>
    ''' <returns>
    ''' All <see cref="Vintasoft.Imaging.Pdf.Tree.PdfResource"/>
    ''' with ZIP compression.
    ''' </returns>
    Public Function GetPdfResourcesWithZipCompression(document As Vintasoft.Imaging.Pdf.PdfDocument) As Vintasoft.Imaging.Pdf.Tree.PdfTreeNodeBase()
        Dim compressions As Vintasoft.Imaging.Pdf.PdfCompression() = New Vintasoft.Imaging.Pdf.PdfCompression() {Vintasoft.Imaging.Pdf.PdfCompression.Zip}

        Return document.Catalog.GetLinearizedSubtree(New ResourceCompressionAnalyzer(compressions))
    End Function


    ''' <summary>
    ''' Analyzes the specified target.
    ''' </summary>
    ''' <param name="target">The target object.</param>
    ''' <returns>
    ''' Logical result of analysis.
    ''' </returns>
    Protected Overrides Function Analyze(target As Vintasoft.Imaging.Pdf.Tree.PdfTreeNodeBase) As Boolean
        ' if target is PdfResource
        If TypeOf target Is Vintasoft.Imaging.Pdf.Tree.PdfResource Then
            ' get PDF resource compression
            Dim pdfResourceCompression As Vintasoft.Imaging.Pdf.PdfCompression = DirectCast(target, Vintasoft.Imaging.Pdf.Tree.PdfResource).Compression

            ' for each compression type, which should be analyzed
            For Each compression As Vintasoft.Imaging.Pdf.PdfCompression In _compressions
                ' if PDF resource uses compression
                If pdfResourceCompression = compression Then
                    Return True
                End If
            Next
        End If
        Return False
    End Function
End Class

/// <summary>
/// A predicate that checks taget compression type.
/// </summary>
public class ResourceCompressionAnalyzer : Vintasoft.Imaging.Processing.Analyzers.PredicateAnalyzer<Vintasoft.Imaging.Pdf.Tree.PdfTreeNodeBase>
{

    /// <summary>
    /// Compression types, which should be analyzed.
    /// </summary>
    Vintasoft.Imaging.Pdf.PdfCompression[] _compressions;



    /// <summary>
    /// Initializes a new instance of the <see cref="ResourceCompressionAnalyzer"/> class.
    /// </summary>
    /// <param name="compressions">Compression types, which should be analyzed.</param>
    public ResourceCompressionAnalyzer(Vintasoft.Imaging.Pdf.PdfCompression[] compressions)
        : base("PDF resource compression analyzer")
    {
        _compressions = compressions;
    }



    /// <summary>
    /// Returns all nodes that are <see cref="Vintasoft.Imaging.Pdf.Tree.PdfResource"/>
    /// with ZIP compression.
    /// </summary>
    /// <param name="document">A PDF document.</param>
    /// <returns>
    /// All <see cref="Vintasoft.Imaging.Pdf.Tree.PdfResource"/>
    /// with ZIP compression.
    /// </returns>
    public Vintasoft.Imaging.Pdf.Tree.PdfTreeNodeBase[] GetPdfResourcesWithZipCompression(Vintasoft.Imaging.Pdf.PdfDocument document)
    {
        Vintasoft.Imaging.Pdf.PdfCompression[] compressions = new Vintasoft.Imaging.Pdf.PdfCompression[] {
            Vintasoft.Imaging.Pdf.PdfCompression.Zip 
        };

        return document.Catalog.GetLinearizedSubtree(
            new ResourceCompressionAnalyzer(compressions));
    }


    /// <summary>
    /// Analyzes the specified target.
    /// </summary>
    /// <param name="target">The target object.</param>
    /// <returns>
    /// Logical result of analysis.
    /// </returns>
    protected override bool Analyze(Vintasoft.Imaging.Pdf.Tree.PdfTreeNodeBase target)
    {
        // if target is PdfResource
        if (target is Vintasoft.Imaging.Pdf.Tree.PdfResource)
        {
            // get PDF resource compression
            Vintasoft.Imaging.Pdf.PdfCompression pdfResourceCompression =
                ((Vintasoft.Imaging.Pdf.Tree.PdfResource)target).Compression;

            // for each compression type, which should be analyzed
            foreach (Vintasoft.Imaging.Pdf.PdfCompression compression in _compressions)
            {
                // if PDF resource uses compression
                if (pdfResourceCompression == compression)
                    return true;
            }
        }
        return false;
    }
}