VintaSoft Barcode .NET SDK 15.1: Documentation for .NET developer
Vintasoft.Barcode.BarcodeInfo Namespace / PDF417StructuredAppendCharacter Class
Members Object Syntax Remarks Example Hierarchy Requirements SeeAlso
In This Topic
    PDF417StructuredAppendCharacter Class
    In This Topic
    Contains information about the PDF417 (Macro PDF417) and Micro PDF417 Structured Append non-data character.
    Object Model
    PDF417StructuredAppendCharacter
    Syntax
    'Declaration
    
    Public NotInheritable Class PDF417StructuredAppendCharacter
       Inherits StructuredAppendCharacter
    
    
    public sealed class PDF417StructuredAppendCharacter : StructuredAppendCharacter
    
    
    public __gc __sealed class PDF417StructuredAppendCharacter : public StructuredAppendCharacter*
    
    
    public ref class PDF417StructuredAppendCharacter sealed : public StructuredAppendCharacter^
    
    
    Remarks

    A Structured Append character is used to indicate that the symbol is part of a Structured Append sequence.
    Structured Append provides a standard mechanism for creating a distributed representation of files too large to be represented by a single PDF417 or Micro PDF417 symbol. Using Structured Append, large files are split into several file segments and encoded into individual symbols. The Structured Append character defines the file ID, the concatenation sequence and optionally other information about the file.
    A Structured Append decoder uses the Structured Append character information to reconstruct the file correctly independently of symbol scanning order.

    For each related Structured Append symbol, the FileID field contains the same value. The file ID is a variable length field composed of triplets. Each triplet in the file ID can have a value between 000 and 899, effectively making the file ID a series of base 900 numbers.

    Structured Append character also contain a number of optional fields. Each optional field has field designator. Field designator defines field type and field encoding mode.
    Pre-defined field designators:

    • 0 - File Name, variable text (FileName).
    • 1 - Segment Count, fixed number 0..99999 (SymbolCount).
    • 2 - Time Stamp, fixed number, indicates the time stamp on the source file expressed as the elapsed time in seconds since 1970:01:01:00:00:00 GMT (TimeStamp).
    • 3 - Sender, variable text (Sender).
    • 4 - Addressee, variable text (Addressee).
    • 5 - FileSize, variable number (FileSize).
    • 6 - Checksum, fiexd number 0..65535 (Checksum).
    Field designator values greater than 6 are not currently defined. However, decoder and transmit any optional fields encountered with a field designator of 7 to 34 by treating the field data as variable text.
    Additional information about PDF417 Structured Append see in: ISO/IEC 24728, ISO/IEC 15438, Annex H.

    Example

    This C#/VB.NET code shows how to split data files into parts and reconstruct data files using PDF417 Structured Append character:

       
    Imports System.Collections.Generic   
    Imports System.Text   
       
    Imports Vintasoft.Barcode   
    Imports Vintasoft.Barcode.BarcodeInfo   
    Imports Vintasoft.Imaging   
       
    Class PDF417StructuredAppendCharacterExample   
        ''' <summary>
        ''' The barcode type (PDF417, PDF417Compact or MicroPDF417).
        ''' </summary>
        Shared _barcodeType As BarcodeType = BarcodeType.PDF417   
       
        ''' <summary>
        ''' Splits 3 files into 9 parts (each file into 3 parts), creates barcodes from 9 parts,
        ''' reorders barcodes, recognizes barcodes and restores content of 3 files.
        ''' </summary>
        Public Shared Sub Test()   
            ' count of data files
            Dim fileCount As Integer = 3   
       
            ' count of parts in data file
            Dim symbolCount As Integer = 3   
       
            ' split data files to symbols
            Dim barcodeImages As New List(Of VintasoftBitmap)()   
            For i As Integer = 0 To fileCount - 1   
                ' file ID - series of triplets 000..899
                Dim fileId As String = (i + 1).ToString().PadLeft(3, "0"C)   
       
                ' split each data file to "symbolCount" symbols
                For j As Integer = 0 To symbolCount - 1   
                    ' create structured append character
                    Dim structureAppendCharacter As New PDF417StructuredAppendCharacter(j + 1, symbolCount, fileId)   
       
                    ' add FileName information to the first symbol of data file
                    If j = 0 Then   
                        structureAppendCharacter.FileName = String.Format("DataFile{0}", i + 1)   
                    End If   
       
                    ' barcode value
                    Dim symbolValue As String = String.Format("[Part {0} of file {1}]", j + 1, i + 1)   
       
                    ' generate barcode image
                    barcodeImages.Add(GenerateBarcode(structureAppendCharacter, symbolValue))   
                Next   
            Next   
       
       
            ' resort barcode images
            barcodeImages.Reverse()   
            barcodeImages.Reverse(0, barcodeImages.Count \ 2)   
            barcodeImages.Reverse(barcodeImages.Count \ 3, (barcodeImages.Count \ 3) * 2)   
       
       
            ' recognize all barcodes and reconstruct data files
            Dim dataFiles As Dictionary(Of String, String) = ReconstructDataFiles(barcodeImages)   
       
            ' print reconstructed data files
            Console.WriteLine("Reconstructed data files:")   
            For Each fileId As String In dataFiles.Keys   
                Console.WriteLine(String.Format("File ID  : {0}", fileId))   
                Console.WriteLine(String.Format("Data File: {0}", dataFiles(fileId)))   
                Console.WriteLine()   
            Next   
        End Sub   
       
        ''' <summary>
        ''' Generates the barcode image.
        ''' </summary>
        ''' <param name="structuredAppend">The structured append character.</param>
        ''' <param name="barcodeValue">The barcode value.</param>
        Private Shared Function GenerateBarcode(structuredAppend As PDF417StructuredAppendCharacter, barcodeValue As String) As VintasoftBitmap   
            Using writer As New BarcodeWriter()   
                writer.Settings.Barcode = _barcodeType   
                writer.Settings.ValueItems = New ValueItemBase() {structuredAppend, New TextValueItem(barcodeValue)}   
                Return writer.GetBarcodeAsVintasoftBitmap()   
            End Using   
        End Function   
       
        ''' <summary>
        ''' Reconstructs the data files.
        ''' </summary>
        ''' <param name="barcodeImages">The barcode images.</param>
        ''' <returns>Dictonary (fileId -> DataFile) that contaions recontructed data files.</returns>
        Private Shared Function ReconstructDataFiles(barcodeImages As List(Of VintasoftBitmap)) As Dictionary(Of String, String)   
            ' create barcode reader
            Using reader As New BarcodeReader()   
                reader.Settings.ScanBarcodeTypes = _barcodeType   
       
                ' Dictionary: FileId -> (symbolPosition -> barcodeValue)
                Dim recognizeBarcodes As New Dictionary(Of String, Dictionary(Of Integer, String))()   
       
                ' for each barcode image
                For i As Integer = 0 To barcodeImages.Count - 1   
                    ' recognize barcode
                    Console.WriteLine(String.Format("Recognize image {0}...", i + 1))   
                    Dim info As IBarcodeInfo = reader.ReadBarcodes(barcodeImages(i))(0)   
                    Dim valueItems As ValueItemBase() = info.ValueItems   
       
                    ' structured append character
                    Dim saCharacter As PDF417StructuredAppendCharacter = DirectCast(valueItems(0), PDF417StructuredAppendCharacter)   
       
                    ' barcode value
                    info.ShowNonDataFlagsInValue = False   
                    Dim barcodeValue As String = info.Value   
       
                    ' show information about recognized barcode
                    Console.WriteLine(String.Format("  Value   : {0}", barcodeValue))   
                    Console.WriteLine(String.Format("  Symbol  : {0} of {1}", saCharacter.SymbolPosition, saCharacter.SymbolCount))   
                    Console.WriteLine(String.Format("  File ID : {0}", saCharacter.FileID))   
                    If saCharacter.FileName IsNot Nothing Then   
                        Console.WriteLine(String.Format("  FileName: {0}", saCharacter.FileName))   
                    End If   
                    Console.WriteLine()   
       
                    ' add barcode value to recognizeBarcodes table
                    Dim positionsToDataFileParts As Dictionary(Of Integer, String)   
                    If Not recognizeBarcodes.TryGetValue(saCharacter.FileID, positionsToDataFileParts) Then   
                        positionsToDataFileParts = New Dictionary(Of Integer, String)()   
                        recognizeBarcodes(saCharacter.FileID) = positionsToDataFileParts   
                    End If   
                    positionsToDataFileParts.Add(saCharacter.SymbolPosition, barcodeValue)   
                Next   
       
                ' reconstruct data files
                Dim dataFiles As New Dictionary(Of String, String)()   
                For Each fileId As String In recognizeBarcodes.Keys   
                    Dim positionsToDataFileParts As Dictionary(Of Integer, String) = recognizeBarcodes(fileId)   
       
                    ' symbol positions
                    Dim positions As Integer() = New Integer(positionsToDataFileParts.Count - 1) {}   
                    positionsToDataFileParts.Keys.CopyTo(positions, 0)   
       
                    ' data file parts
                    Dim dataFileParts As String() = New String(positionsToDataFileParts.Count - 1) {}   
                    positionsToDataFileParts.Values.CopyTo(dataFileParts, 0)   
       
                    ' sort data file parts by symbol posiotions
                    Array.Sort(positions, dataFileParts)   
       
                    ' merge data file parts
                    Dim dataFile As New StringBuilder()   
                    For Each dataFilePart As String In dataFileParts   
                        dataFile.Append(dataFilePart)   
                    Next   
                    dataFiles(fileId) = dataFile.ToString()   
                Next   
       
                Return dataFiles   
            End Using   
        End Function   
    End Class   
       
    ' This code example produces the following output:
    '
    'Recognize image 1...
    '  Value   : [Part 3 of file 2]
    '  Symbol  : 3 of 3
    '  File ID : 002
    '
    'Recognize image 2...
    '  Value   : [Part 1 of file 3]
    '  Symbol  : 1 of 3
    '  File ID : 003
    '  FileName: DataFile3
    '
    'Recognize image 3...
    '  Value   : [Part 2 of file 3]
    '  Symbol  : 2 of 3
    '  File ID : 003
    '
    'Recognize image 4...
    '  Value   : [Part 1 of file 1]
    '  Symbol  : 1 of 3
    '  File ID : 001
    '  FileName: DataFile1
    '
    'Recognize image 5...
    '  Value   : [Part 2 of file 1]
    '  Symbol  : 2 of 3
    '  File ID : 001
    '
    'Recognize image 6...
    '  Value   : [Part 3 of file 1]
    '  Symbol  : 3 of 3
    '  File ID : 001
    '
    'Recognize image 7...
    '  Value   : [Part 1 of file 2]
    '  Symbol  : 1 of 3
    '  File ID : 002
    '  FileName: DataFile2
    '
    'Recognize image 8...
    '  Value   : [Part 2 of file 2]
    '  Symbol  : 2 of 3
    '  File ID : 002
    '
    'Recognize image 9...
    '  Value   : [Part 3 of file 3]
    '  Symbol  : 3 of 3
    '  File ID : 003
    '
    'Reconstructed data files:
    'File ID  : 002
    'Data File: [Part 1 of file 2][Part 2 of file 2][Part 3 of file 2]
    '
    'File ID  : 003
    'Data File: [Part 1 of file 3][Part 2 of file 3][Part 3 of file 3]
    '
    'File ID  : 001
    'Data File: [Part 1 of file 1][Part 2 of file 1][Part 3 of file 1]
    '
       
    
    
    
    
    using System;
    using System.Collections.Generic;
    using System.Text;
    
    using Vintasoft.Barcode;
    using Vintasoft.Barcode.BarcodeInfo;
    using Vintasoft.Imaging;
    
    class PDF417StructuredAppendCharacterExample
    {
        /// <summary>
        /// The barcode type (PDF417, PDF417Compact or MicroPDF417).
        /// </summary>
        static BarcodeType _barcodeType = BarcodeType.PDF417;
    
        /// <summary>
        /// Splits 3 files into 9 parts (each file into 3 parts), creates barcodes from 9 parts,
        /// reorders barcodes, recognizes barcodes and restores content of 3 files.
        /// </summary>
        public static void Test()
        {
            // count of data files
            int fileCount = 3;
    
            // count of parts in data file
            int symbolCount = 3;
    
            // split data files to symbols
            List<VintasoftBitmap> barcodeImages = new List<VintasoftBitmap>();
            for (int i = 0; i < fileCount; i++)
            {
                // file ID - series of triplets 000..899
                string fileId = (i + 1).ToString().PadLeft(3, '0');
                
                // split each data file to "symbolCount" symbols
                for (int j = 0; j < symbolCount; j++)
                {
                    // create structured append character
                    PDF417StructuredAppendCharacter structureAppendCharacter =
                        new PDF417StructuredAppendCharacter(j + 1, symbolCount, fileId);
                    
                    // add FileName information to the first symbol of data file
                    if (j == 0)
                        structureAppendCharacter.FileName = string.Format("DataFile{0}", i + 1);
                    
                    // barcode value
                    string symbolValue = string.Format("[Part {0} of file {1}]", j + 1, i + 1);
    
                    // generate barcode image
                    barcodeImages.Add(GenerateBarcode(structureAppendCharacter, symbolValue));
                }
            }
    
    
            // resort barcode images
            barcodeImages.Reverse();
            barcodeImages.Reverse(0, barcodeImages.Count / 2);
            barcodeImages.Reverse(barcodeImages.Count / 3, (barcodeImages.Count / 3) * 2);
    
    
            // recognize all barcodes and reconstruct data files
            Dictionary<string, string> dataFiles = ReconstructDataFiles(barcodeImages);
    
            // print reconstructed data files
            Console.WriteLine("Reconstructed data files:");
            foreach (string fileId in dataFiles.Keys)
            {
                Console.WriteLine(string.Format("File ID  : {0}", fileId));
                Console.WriteLine(string.Format("Data File: {0}", dataFiles[fileId]));
                Console.WriteLine();
            }
        }
    
        /// <summary>
        /// Generates the barcode image.
        /// </summary>
        /// <param name="structuredAppend">The structured append character.</param>
        /// <param name="barcodeValue">The barcode value.</param>
        private static VintasoftBitmap GenerateBarcode(
            PDF417StructuredAppendCharacter structuredAppend,
            string barcodeValue)
        {
            using (BarcodeWriter writer = new BarcodeWriter())
            {
                writer.Settings.Barcode = _barcodeType;
                writer.Settings.ValueItems = new ValueItemBase[] {
                structuredAppend, new TextValueItem(barcodeValue) };
                return writer.GetBarcodeAsVintasoftBitmap();
            }
        }
    
        /// <summary>
        /// Reconstructs the data files.
        /// </summary>
        /// <param name="barcodeImages">The barcode images.</param>
        /// <returns>Dictonary (fileId -> DataFile) that contaions recontructed data files.</returns>
        private static Dictionary<string, string> ReconstructDataFiles(List<VintasoftBitmap> barcodeImages)
        {
            // create barcode reader
            using (BarcodeReader reader = new BarcodeReader())
            {
                reader.Settings.ScanBarcodeTypes = _barcodeType;
    
                // Dictionary: FileId -> (symbolPosition -> barcodeValue)
                Dictionary<string, Dictionary<int, string>> recognizeBarcodes =
                    new Dictionary<string, Dictionary<int, string>>();
    
                // for each barcode image
                for (int i = 0; i < barcodeImages.Count; i++)
                {
                    // recognize barcode
                    Console.WriteLine(string.Format("Recognize image {0}...", i + 1));
                    IBarcodeInfo info = reader.ReadBarcodes(barcodeImages[i])[0];
                    ValueItemBase[] valueItems = info.ValueItems;
    
                    // structured append character
                    PDF417StructuredAppendCharacter saCharacter = (PDF417StructuredAppendCharacter)valueItems[0];
    
                    // barcode value
                    info.ShowNonDataFlagsInValue = false;
                    string barcodeValue = info.Value;
    
                    // show information about recognized barcode
                    Console.WriteLine(string.Format("  Value   : {0}", barcodeValue));
                    Console.WriteLine(string.Format("  Symbol  : {0} of {1}", saCharacter.SymbolPosition, saCharacter.SymbolCount));
                    Console.WriteLine(string.Format("  File ID : {0}", saCharacter.FileID));
                    if (saCharacter.FileName != null)
                        Console.WriteLine(string.Format("  FileName: {0}", saCharacter.FileName));
                    Console.WriteLine();
    
                    // add barcode value to recognizeBarcodes table
                    Dictionary<int, string> positionsToDataFileParts;
                    if (!recognizeBarcodes.TryGetValue(saCharacter.FileID, out positionsToDataFileParts))
                    {
                        positionsToDataFileParts = new Dictionary<int, string>();
                        recognizeBarcodes[saCharacter.FileID] = positionsToDataFileParts;
                    }
                    positionsToDataFileParts.Add(saCharacter.SymbolPosition, barcodeValue);
                }
    
                // reconstruct data files
                Dictionary<string, string> dataFiles = new Dictionary<string, string>();
                foreach (string fileId in recognizeBarcodes.Keys)
                {
                    Dictionary<int, string> positionsToDataFileParts = recognizeBarcodes[fileId];
    
                    // symbol positions
                    int[] positions = new int[positionsToDataFileParts.Count];
                    positionsToDataFileParts.Keys.CopyTo(positions, 0);
    
                    // data file parts
                    string[] dataFileParts = new string[positionsToDataFileParts.Count];
                    positionsToDataFileParts.Values.CopyTo(dataFileParts, 0);
    
                    // sort data file parts by symbol posiotions
                    Array.Sort(positions, dataFileParts);
    
                    // merge data file parts
                    StringBuilder dataFile = new StringBuilder();
                    foreach (string dataFilePart in dataFileParts)
                        dataFile.Append(dataFilePart);
                    dataFiles[fileId] = dataFile.ToString();
                }
    
                return dataFiles;
            }
        }
    }
    
    /* This code example produces the following output:
    
    Recognize image 1...
      Value   : [Part 3 of file 2]
      Symbol  : 3 of 3
      File ID : 002
    
    Recognize image 2...
      Value   : [Part 1 of file 3]
      Symbol  : 1 of 3
      File ID : 003
      FileName: DataFile3
    
    Recognize image 3...
      Value   : [Part 2 of file 3]
      Symbol  : 2 of 3
      File ID : 003
    
    Recognize image 4...
      Value   : [Part 1 of file 1]
      Symbol  : 1 of 3
      File ID : 001
      FileName: DataFile1
    
    Recognize image 5...
      Value   : [Part 2 of file 1]
      Symbol  : 2 of 3
      File ID : 001
    
    Recognize image 6...
      Value   : [Part 3 of file 1]
      Symbol  : 3 of 3
      File ID : 001
    
    Recognize image 7...
      Value   : [Part 1 of file 2]
      Symbol  : 1 of 3
      File ID : 002
      FileName: DataFile2
    
    Recognize image 8...
      Value   : [Part 2 of file 2]
      Symbol  : 2 of 3
      File ID : 002
    
    Recognize image 9...
      Value   : [Part 3 of file 3]
      Symbol  : 3 of 3
      File ID : 003
    
    Reconstructed data files:
    File ID  : 002
    Data File: [Part 1 of file 2][Part 2 of file 2][Part 3 of file 2]
    
    File ID  : 003
    Data File: [Part 1 of file 3][Part 2 of file 3][Part 3 of file 3]
    
    File ID  : 001
    Data File: [Part 1 of file 1][Part 2 of file 1][Part 3 of file 1]
    */
    
    
    

    Inheritance Hierarchy

    System.Object
       Vintasoft.Barcode.BarcodeInfo.ValueItemBase
          Vintasoft.Barcode.BarcodeInfo.NonDataFlagValueItem
             Vintasoft.Barcode.BarcodeInfo.StructuredAppendCharacter
                Vintasoft.Barcode.BarcodeInfo.PDF417StructuredAppendCharacter

    Requirements

    Target Platforms: .NET9; .NET 8; .NET 7; .NET 6; .NET Framework 4.8, 4.7, 4.6, 4.5, 4.0, 3.5

    See Also