/// <summary>
/// Writes the header to the specified stream.
/// </summary>
/// <param name="stream">The stream.</param>
/// <param name="sampleRecord">The sample record.</param>
public void Write(Stream stream, IDictionary <String, Object> sampleRecord)
{
_bytesInRecord = 1;
_fields = new List <DBaseField>();
foreach (String key in sampleRecord.Keys)
{
DBaseField field = DBaseField.FromRecord(key, sampleRecord[key]);
_fields.Add(field);
_bytesInRecord += (Int16)field.FieldLength;
}
_numOfRecords = 0;
_bytesInHeader = (Int16)(32 + (sampleRecord.Count * 32) + 1);
Byte[] headerBytes = new Byte[_bytesInHeader];
headerBytes[0] = _identifier; // write dBase ID
headerBytes[1] = (Byte)(_lastUpdate.Year - 1900); // write last update time
headerBytes[2] = (Byte)_lastUpdate.Month;
headerBytes[3] = (Byte)_lastUpdate.Day;
headerBytes[headerBytes.Length - 1] = FieldTerminator;
EndianBitConverter.CopyBytes(_numOfRecords, headerBytes, 4, ByteOrder.LittleEndian);
EndianBitConverter.CopyBytes(_bytesInHeader, headerBytes, 8, ByteOrder.LittleEndian);
EndianBitConverter.CopyBytes(_bytesInRecord, headerBytes, 10, ByteOrder.LittleEndian);
Int32 headerIndex = 32;
foreach (DBaseField field in _fields)
{
Array.Copy(field.ToByteArray(), 0, headerBytes, headerIndex, 32);
headerIndex += 32;
}
stream.Write(headerBytes, 0, headerBytes.Length);
}
/// <summary>
/// Initializes a new instance of the <see cref="DBaseHeader"/> class.
/// </summary>
/// <param name="stream">The source stream.</param>
/// <exception cref="System.ArgumentNullException">The stream is null.</exception>
/// <exception cref="System.IO.InvalidDataException">The specified dBase format is not supported.</exception>
public DBaseHeader(Stream stream) : this()
{
if (stream == null)
{
throw new ArgumentNullException("stream", "The stream is null.");
}
Byte[] headerBuffer = new Byte[32];
stream.Read(headerBuffer, 0, 32);
_identifier = headerBuffer[0];
if (_identifier != DBaseIIIPlusIdentifier && _identifier != (Byte)0x04)
{
throw new InvalidDataException("The specified dBase format is not supported.");
}
_lastUpdate = new DateTime(1900 + headerBuffer[1], headerBuffer[2], headerBuffer[3]);
_numOfRecords = EndianBitConverter.ToInt32(headerBuffer, 4, ByteOrder.LittleEndian);
_bytesInHeader = EndianBitConverter.ToInt16(headerBuffer, 8, ByteOrder.LittleEndian);
_bytesInRecord = EndianBitConverter.ToInt16(headerBuffer, 10, ByteOrder.LittleEndian);
Byte b = headerBuffer[29];
DBaseField field = DBaseField.FromStream(stream);
while (field != null)
{
_fields.Add(field);
field = DBaseField.FromStream(stream);
}
}
/// <summary>
/// Creates the field from a stream.
/// </summary>
/// <param name="stream">The stream.</param>
/// <returns>The produced dBase field.</returns>
/// <exception cref="System.ArgumentNullException">The stream is null.</exception>
public static DBaseField FromStream(Stream stream)
{
if (stream == null)
{
throw new ArgumentNullException("stream", "The stream is null.");
}
DBaseField result = new DBaseField();
Byte[] buffer = new Byte[14];
buffer[0] = (Byte)stream.ReadByte();
if (buffer[0] == FieldTerminator) // we reached the end of the field descriptor
{
return(null);
}
stream.Read(buffer, 1, 10);
for (Int32 i = 0; i < 11; i++)
{
if (buffer[i] == (Byte)0)
{
result._nameLength = i;
break;
}
}
if (result._nameLength == 0)
{
result._nameLength = 11;
}
result._name = Encoding.ASCII.GetString(buffer, 0, result._nameLength);
result._type = Convert.ToChar(stream.ReadByte());
stream.Read(buffer, 0, 4);
result._dataAddress = EndianBitConverter.ToInt32(buffer, 0, ByteOrder.LittleEndian);
result._length = stream.ReadByte();
result._decimalCount = stream.ReadByte();
stream.Read(buffer, 0, 14);
return(result);
}
/// <summary>
/// Creates the field from a metadata record name and value.
/// </summary>
/// <param name="name">The record name.</param>
/// <param name="value">The record value.</param>
/// <returns>The produced dDbase field.</returns>
/// <exception cref="System.ArgumentNullException">
/// The name is null.
/// or
/// The value is null.
/// </exception>
/// <exception cref="System.ArgumentException">
/// The name is empty or consists only of white-space characters.
/// or
/// The length of the name is more than the maximum supported by the field (10).
/// or
/// The value is null.
/// </exception>
public static DBaseField FromRecord(String name, Object value)
{
if (name == null)
{
throw new ArgumentNullException("name", "The name is null.");
}
if (String.IsNullOrWhiteSpace(name))
{
throw new ArgumentException("The name is empty or consists only of white-space characters.", "name");
}
if (name.Length > 10)
{
throw new ArgumentException("The length of the name is more than the maximum supported by the field (10).", "name");
}
if (value == null)
{
throw new ArgumentNullException("value", "The value is null.");
}
DBaseField result = new DBaseField();
result._name = name;
result._nameLength = name.Length;
switch (Type.GetTypeCode(value.GetType()))
{
case TypeCode.Char:
case TypeCode.String:
result._type = 'C';
result._decimalCount = 0;
result._length = 255;
break;
case TypeCode.Int16:
case TypeCode.Int32:
case TypeCode.Int64:
result._type = 'N';
result._decimalCount = 0;
result._length = 18;
break;
case TypeCode.Single:
case TypeCode.Double:
result._type = 'N';
result._decimalCount = 8;
result._length = 18;
break;
case TypeCode.Boolean:
result._type = 'L';
result._decimalCount = 0;
result._length = 1;
break;
case TypeCode.DateTime:
result._type = 'D';
result._decimalCount = 0;
result._length = 8;
break;
}
return(result);
}