''' <summary>
''' Tests add/get custom data.
''' </summary>
Public Shared Sub Test()
    ' create PDF document
    Using document As New Vintasoft.Imaging.Pdf.PdfDocument("textCustomData.pdf", Vintasoft.Imaging.Pdf.PdfFormat.Pdf_14)
        ' add empty page to the PDF document
        Dim page As Vintasoft.Imaging.Pdf.Tree.PdfPage = document.Pages.Add(Vintasoft.Imaging.PaperSizeKind.A4)

        ' add custom data to the PDF document catalog
        AddCustomStringData(document.Catalog, "MyStringData", "Test String Value 1")
        AddCustomStreamData(document.Catalog, "MyStreamData", System.Text.Encoding.Unicode.GetBytes("Test Stream Data 1"))

        ' add custom data to the PDF page
        AddCustomStringData(page, "MyStringData", "Test String Value 2")
        AddCustomStreamData(page, "MyStreamData", System.Text.Encoding.Unicode.GetBytes("Test Stream Data 2"))

        ' save changes in PDF document
        document.SaveChanges()
    End Using

    ' open PDF document
    Using document As New Vintasoft.Imaging.Pdf.PdfDocument("textCustomData.pdf")
        ' read "/MyStringData" entry from the PDF document catalog
        System.Console.WriteLine(GetCustomStringData(document.Catalog, "MyStringData"))

        ' read "/MyStreamData" entry from the PDF document catalog
        System.Console.WriteLine(System.Text.Encoding.Unicode.GetString(GetCustomStreamData(document.Catalog, "MyStreamData")))

        ' read "/MyStringData" entry from PDF page
        System.Console.WriteLine(GetCustomStringData(document.Pages(0), "MyStringData"))

        ' read "/MyStreamData" entry from PDF page
        System.Console.WriteLine(System.Text.Encoding.Unicode.GetString(GetCustomStreamData(document.Pages(0), "MyStreamData")))
    End Using
End Sub

''' <summary>
''' Adds the custom string data with the specified name to the specified PDF tree node.
''' </summary>
''' <param name="pdfTreeNode">The PDF tree node.</param>
''' <param name="dataName">The data name.</param>
''' <param name="dataValue">The data value.</param>
Public Shared Sub AddCustomStringData(pdfTreeNode As Vintasoft.Imaging.Pdf.Tree.PdfTreeNodeBase, dataName As String, dataValue As String)
    Dim dictionary As Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary = GetDictionary(pdfTreeNode)
    If dictionary.ContainsKey(dataName) Then
        Throw New System.ArgumentException(String.Format("Key '{0}' already exists.", dataName))
    End If
    dictionary(dataName) = New Vintasoft.Imaging.Pdf.BasicTypes.PdfString(dataValue)
End Sub

''' <summary>
''' Returns the custom string data with the specified name from the specified PDF tree node.
''' </summary>
''' <param name="pdfTreeNode">The PDF tree node.</param>
''' <param name="dataName">The data name.</param>
''' <returns>The custom string data with the specified name from the specified PDF tree node.</returns>
Public Shared Function GetCustomStringData(pdfTreeNode As Vintasoft.Imaging.Pdf.Tree.PdfTreeNodeBase, dataName As String) As String
    Dim dictionary As Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary = GetDictionary(pdfTreeNode)
    If dictionary.ContainsKey(dataName) Then
        Return DirectCast(dictionary(dataName), Vintasoft.Imaging.Pdf.BasicTypes.PdfString).ValueAsTextString
    End If
    Throw New System.ArgumentException(String.Format("Key '{0}' is not found.", dataName))
End Function

''' <summary>
''' Adds the custom stream data with the specified name to the specified PDF tree node.
''' </summary>
''' <param name="pdfTreeNode">The PDF tree node.</param>
''' <param name="dataName">The data name.</param>
''' <param name="dataValue">The data value.</param>
Public Shared Sub AddCustomStreamData(pdfTreeNode As Vintasoft.Imaging.Pdf.Tree.PdfTreeNodeBase, dataName As String, dataValue As Byte())
    Dim dictionary As Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary = GetDictionary(pdfTreeNode)
    If dictionary.ContainsKey(dataName) Then
        Throw New System.ArgumentException(String.Format("Key '{0}' already exists.", dataName))
    End If
    ' create a stream
    Dim stream As New Vintasoft.Imaging.Pdf.BasicTypes.PdfStream(pdfTreeNode.Document)
    ' write data, compressed with ZIP compression, to the stream
    stream.SetBytes(dataValue, Vintasoft.Imaging.Pdf.PdfCompression.Zip, Vintasoft.Imaging.Pdf.PdfCompressionSettings.DefaultSettings)
    ' create an indirect object from the stream
    Dim indirectObject As Vintasoft.Imaging.Pdf.BasicTypes.PdfIndirectObject = Vintasoft.Imaging.Pdf.BasicTypes.PdfIndirectObject.Create(pdfTreeNode.Document, stream)
    ' set the reference for the specified entry
    dictionary(dataName) = indirectObject.GetReference()
End Sub

''' <summary>
''' Returns the custom stream data with specified name from specified tree node.
''' </summary>
''' <param name="pdfTreeNode">The PDF tree node.</param>
''' <param name="dataName">The data name.</param>
Public Shared Function GetCustomStreamData(pdfTreeNode As Vintasoft.Imaging.Pdf.Tree.PdfTreeNodeBase, dataName As String) As Byte()
    Dim dictionary As Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary = GetDictionary(pdfTreeNode)
    If dictionary.ContainsKey(dataName) Then
        Dim reference As Vintasoft.Imaging.Pdf.BasicTypes.PdfIndirectReference = DirectCast(dictionary(dataName), Vintasoft.Imaging.Pdf.BasicTypes.PdfIndirectReference)
        Dim indirectObject As Vintasoft.Imaging.Pdf.BasicTypes.PdfIndirectObject = Vintasoft.Imaging.Pdf.BasicTypes.PdfIndirectObject.GetByReference(reference)
        Dim stream As Vintasoft.Imaging.Pdf.BasicTypes.PdfStream = DirectCast(indirectObject.Value, Vintasoft.Imaging.Pdf.BasicTypes.PdfStream)
        Return stream.GetBytes()
    End If
    Throw New System.ArgumentException(String.Format("Key '{0}' is not found.", dataName))
End Function

''' <summary>
''' Returns the dictionary from PDF tree node.
''' </summary>
''' <param name="node">The node.</param>
Private Shared Function GetDictionary(node As Vintasoft.Imaging.Pdf.Tree.PdfTreeNodeBase) As Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary
    Dim dictionary As Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary = TryCast(node.BasicObject, Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary)
    If dictionary Is Nothing Then
        Throw New System.ArgumentException(String.Format("Node {0} is not a dictionary!", node.[GetType]().Name))
    End If
    Return dictionary
End Function 

/// <summary>
/// Tests add/get custom data.
/// </summary>
public static void Test()
{
    // create PDF document
    using (Vintasoft.Imaging.Pdf.PdfDocument document = 
        new Vintasoft.Imaging.Pdf.PdfDocument("textCustomData.pdf", Vintasoft.Imaging.Pdf.PdfFormat.Pdf_14))
    {
        // add empty page to the PDF document
        Vintasoft.Imaging.Pdf.Tree.PdfPage page = document.Pages.Add(Vintasoft.Imaging.PaperSizeKind.A4);
        
        // add custom data to the PDF document catalog
        AddCustomStringData(document.Catalog, 
            "MyStringData", "Test String Value 1");                
        AddCustomStreamData(document.Catalog, 
            "MyStreamData", System.Text.Encoding.Unicode.GetBytes("Test Stream Data 1"));
        
        // add custom data to the PDF page
        AddCustomStringData(page, 
            "MyStringData", "Test String Value 2");
        AddCustomStreamData(page, 
            "MyStreamData", System.Text.Encoding.Unicode.GetBytes("Test Stream Data 2"));

        // save changes in PDF document
        document.SaveChanges();
    }

    // open PDF document
    using (Vintasoft.Imaging.Pdf.PdfDocument document = 
        new Vintasoft.Imaging.Pdf.PdfDocument("textCustomData.pdf"))
    {
        // read "/MyStringData" entry from the PDF document catalog
        System.Console.WriteLine(
            GetCustomStringData(document.Catalog, "MyStringData"));

        // read "/MyStreamData" entry from the PDF document catalog
        System.Console.WriteLine(
            System.Text.Encoding.Unicode.GetString(GetCustomStreamData(document.Catalog, "MyStreamData")));
        
        // read "/MyStringData" entry from PDF page
        System.Console.WriteLine(
            GetCustomStringData(document.Pages[0], "MyStringData"));
        
        // read "/MyStreamData" entry from PDF page
        System.Console.WriteLine(
            System.Text.Encoding.Unicode.GetString(GetCustomStreamData(document.Pages[0], "MyStreamData")));
    }
}       

/// <summary>
/// Adds the custom string data with the specified name to the specified PDF tree node.
/// </summary>
/// <param name="pdfTreeNode">The PDF tree node.</param>
/// <param name="dataName">The data name.</param>
/// <param name="dataValue">The data value.</param>
public static void AddCustomStringData(
    Vintasoft.Imaging.Pdf.Tree.PdfTreeNodeBase pdfTreeNode,
    string dataName,
    string dataValue)
{
    Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary dictionary = GetDictionary(pdfTreeNode);
    if (dictionary.ContainsKey(dataName))
        throw new System.ArgumentException(string.Format("Key '{0}' already exists.", dataName));
    dictionary[dataName] = new Vintasoft.Imaging.Pdf.BasicTypes.PdfString(dataValue);
}

/// <summary>
/// Returns the custom string data with the specified name from the specified PDF tree node.
/// </summary>
/// <param name="pdfTreeNode">The PDF tree node.</param>
/// <param name="dataName">The data name.</param>
/// <returns>The custom string data with the specified name from the specified PDF tree node.</returns>
public static string GetCustomStringData(Vintasoft.Imaging.Pdf.Tree.PdfTreeNodeBase pdfTreeNode, string dataName)
{
    Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary dictionary = GetDictionary(pdfTreeNode);
    if (dictionary.ContainsKey(dataName))
        return ((Vintasoft.Imaging.Pdf.BasicTypes.PdfString)dictionary[dataName]).ValueAsTextString;
    throw new System.ArgumentException(string.Format("Key '{0}' is not found.", dataName));
}

/// <summary>
/// Adds the custom stream data with the specified name to the specified PDF tree node.
/// </summary>
/// <param name="pdfTreeNode">The PDF tree node.</param>
/// <param name="dataName">The data name.</param>
/// <param name="dataValue">The data value.</param>
public static void AddCustomStreamData(
    Vintasoft.Imaging.Pdf.Tree.PdfTreeNodeBase pdfTreeNode,
    string dataName,
    byte[] dataValue)
{
    Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary dictionary = GetDictionary(pdfTreeNode);
    if (dictionary.ContainsKey(dataName))
        throw new System.ArgumentException(string.Format("Key '{0}' already exists.", dataName));
    // create a stream
    Vintasoft.Imaging.Pdf.BasicTypes.PdfStream stream = 
        new Vintasoft.Imaging.Pdf.BasicTypes.PdfStream(pdfTreeNode.Document);
    // write data, compressed with ZIP compression, to the stream
    stream.SetBytes(dataValue, Vintasoft.Imaging.Pdf.PdfCompression.Zip, 
        Vintasoft.Imaging.Pdf.PdfCompressionSettings.DefaultSettings);
    // create an indirect object from the stream
    Vintasoft.Imaging.Pdf.BasicTypes.PdfIndirectObject indirectObject = 
        Vintasoft.Imaging.Pdf.BasicTypes.PdfIndirectObject.Create(pdfTreeNode.Document, stream);
    // set the reference for the specified entry
    dictionary[dataName] = indirectObject.GetReference();
}

/// <summary>
/// Returns the custom stream data with specified name from specified tree node.
/// </summary>
/// <param name="pdfTreeNode">The PDF tree node.</param>
/// <param name="dataName">The data name.</param>
public static byte[] GetCustomStreamData(Vintasoft.Imaging.Pdf.Tree.PdfTreeNodeBase pdfTreeNode, string dataName)
{
    Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary dictionary = GetDictionary(pdfTreeNode);
    if (dictionary.ContainsKey(dataName))
    {
        Vintasoft.Imaging.Pdf.BasicTypes.PdfIndirectReference reference = 
            (Vintasoft.Imaging.Pdf.BasicTypes.PdfIndirectReference)dictionary[dataName];
        Vintasoft.Imaging.Pdf.BasicTypes.PdfIndirectObject indirectObject = 
            Vintasoft.Imaging.Pdf.BasicTypes.PdfIndirectObject.GetByReference(reference);
        Vintasoft.Imaging.Pdf.BasicTypes.PdfStream stream = 
            (Vintasoft.Imaging.Pdf.BasicTypes.PdfStream)indirectObject.Value;
        return stream.GetBytes();
    }
    throw new System.ArgumentException(string.Format("Key '{0}' is not found.", dataName));
}

/// <summary>
/// Returns the dictionary from PDF tree node.
/// </summary>
/// <param name="node">The node.</param>
private static Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary GetDictionary(
    Vintasoft.Imaging.Pdf.Tree.PdfTreeNodeBase node)
{
    Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary dictionary = 
        node.BasicObject as Vintasoft.Imaging.Pdf.BasicTypes.PdfDictionary;
    if (dictionary == null)
        throw new System.ArgumentException(
            string.Format("Node {0} is not a dictionary!", node.GetType().Name));
    return dictionary;
}