private void FillVFPFields(Stream fs, DbfHeader header, DatabaseTable dbTable)
{
const int fieldSize = 32;
header.Fields = new List <DbfField>();
fs.Seek(32, SeekOrigin.Begin);
var fieldBuf = bufferPool.Rent(fieldSize);
var index = 0;
int nullFieldIndex = -1;
while (fs.Read(fieldBuf, 0, fieldSize) != 0 && fieldBuf[0] != FieldDescriptorTerminator)
{
var field = new VfpField
{
Name = encoding.GetString(fieldBuf, 0, 10).TrimEnd('\0'),
Type = (char)fieldBuf[11],
Displacement = BTOI(fieldBuf, 12),
Length = fieldBuf[16],
DecimalCount = fieldBuf[17],
Flags = (DbfFieldFlags)fieldBuf[18],
NextAutoIncrement = BTOI(fieldBuf, 19),
AutoIncrementStep = fieldBuf[23],
Index = index,
VarLengthSizeIndex = -1,
NullFieldIndex = -1,
};
if (field.Type == 'V' || field.Type == 'Q')
{
nullFieldIndex++;
field.VarLengthSizeIndex = nullFieldIndex;
}
if ((field.Flags & DbfFieldFlags.Null) != 0)
{
nullFieldIndex++;
field.NullFieldIndex = nullFieldIndex;
}
Buffer.BlockCopy(fieldBuf, 24, field.Reserved24To31 = new byte[8], 0, 8);
if (dbTable != null && dbTable.Fields.Count > index)
{
field.Name = dbTable.Fields[index].Name;
}
header.Fields.Add(field);
index++;
}
bufferPool.Return(fieldBuf);
}
private void FillBacklink(Stream fs, DbfHeader header)
{
const int maxBacklinkLengh = 263;
fs.Seek(header.HeaderSize - maxBacklinkLengh, SeekOrigin.Begin);
var fieldBuf = bufferPool.Rent(maxBacklinkLengh);
var read = fs.Read(fieldBuf, 0, maxBacklinkLengh);
var backlinkLength = read;
if (read != 0)
{
var nullIdx = GetIndexOf(fieldBuf, 0, 0);
if (nullIdx != -1)
{
backlinkLength = nullIdx;
}
}
header.Backlink = encoding.GetString(fieldBuf, 0, backlinkLength);
bufferPool.Return(fieldBuf);
}
public DbfHeader GetHeader()
{
var header = new DbfHeader();
using (var fs = OpenReadOnly())
{
header.Type = (DbfType)fs.ReadByte();
fs.Position = 4;
header.RecordCount = fs.ReadInt();
header.HeaderSize = fs.ReadShort();
header.RecordLength = fs.ReadShort();
header.FileSize = fs.Length;
fs.Position = 28;
header.Flags = (DbfHeaderFlags)fs.ReadByte();
switch (header.Type)
{
case DbfType.VisualFoxPro:
case DbfType.VisualFoxProAutoInc:
case DbfType.VisualFoxProVar:
DatabaseTable dbTable = null;
if ((header.Flags & DbfHeaderFlags.DBC) == 0)
{
FillBacklink(fs, header);
if (!string.IsNullOrEmpty(header.Backlink))
{
var db = Database.FromDbf(new Dbf(Path.Combine(Path.GetDirectoryName(dbfPath), header.Backlink)));
dbTable = db.Tables.Find(t => t.Name.Equals(Path.GetFileNameWithoutExtension(dbfPath), StringComparison.OrdinalIgnoreCase));
}
}
FillVFPFields(fs, header, dbTable);
break;
default:
throw new NotSupportedException($"Field Data for DBF-Type {header.Type} is not supported.");
}
}
return(header);
}
public DbfReader(Dbf dbf, Encoding textEncoding)
{
DbfTypeMap.Add('C', (i, b, f, e) =>
{
if (f.Length == 1)
{
return(e.GetString(b)[0]);
}
return(e.GetString(b).TrimEnd('\0'));
});
DbfTypeMap.Add('M', (i, b, f, e) => BitConverter.ToInt32(b));
DbfTypeMap.Add('W', (i, b, f, e) => BitConverter.ToInt32(b));
DbfTypeMap.Add('G', (i, b, f, e) => BitConverter.ToInt32(b));
DbfTypeMap.Add('Y', (i, b, f, e) => BitConverter.ToInt64(b) / 10000m); // Stored as int64 with 4 implicit decimal places
DbfTypeMap.Add('D', (i, b, f, e) =>
{
var dateStr = e.GetString(b).Trim(); return(dateStr == "" ? DateTime.MinValue : DateTime.ParseExact(dateStr, "yyyyMMdd", null));
});
DbfTypeMap.Add('T', (i, b, f, e) => JulianDateHelper.FromULongBuffer(b));
DbfTypeMap.Add('N', (i, b, f, e) =>
{
var numStr = e.GetString(b).Trim();
if (f.DecimalCount == 0)
{
if (f.Length < 3)
{
if (numStr == "")
{
return((byte)0);
}
return(byte.Parse(numStr));
}
else if (f.Length < 5)
{
if (numStr == "")
{
return((short)0);
}
return(short.Parse(numStr));
}
else if (f.Length < 10)
{
if (numStr == "")
{
return((int)0);
}
return(int.Parse(numStr));
}
else if (f.Length < 19)
{
if (numStr == "")
{
return((long)0);
}
return(long.Parse(numStr));
}
}
return(numStr == "" ? 0m : decimal.Parse(numStr));
});
DbfTypeMap.Add('B', (i, b, f, e) => BitConverter.ToInt32(b));
DbfTypeMap.Add('O', (i, b, f, e) => BitConverter.ToDouble(b));
DbfTypeMap.Add('F', (i, b, f, e) => { var numStr = e.GetString(b).Trim(); return(numStr == "" ? 0f : float.Parse(numStr)); });
DbfTypeMap.Add('I', (i, b, f, e) => BitConverter.ToInt32(b));
DbfTypeMap.Add('L', (i, b, f, e) => BitConverter.ToBoolean(b));
DbfTypeMap.Add('Q', CopyFieldBuffer);
DbfTypeMap.Add('P', CopyFieldBuffer);
this.dbf = dbf;
TextEncoding = textEncoding;
dbfHeader = dbf.GetHeader();
if (IsVisualFoxPro(dbfHeader))
{ // Special handling for VFP
DbfTypeMap['B'] = (i, b, f, e) => BitConverter.ToDouble(b);
// VarChar/VarBinary
// SPECIAL CASE for VARCHAR/BINARY
DbfTypeMap['V'] = (i, b, f, e) => f.Flags.HasFlag(DbfFieldFlags.Binary) ? CopyFieldBuffer(i, b, f, e) : e.GetString(b);
// _NullFlags
nullField = dbfHeader.Fields.FirstOrDefault(x => x.Type == '0');
nullFieldDataHandler = DbfTypeMap['0'] = CopyFieldBuffer;
if (nullField != null)
{
if (nullField.Length == 1)
{
nullFieldHandlerFactory = (i, b, f, e) => new UIntNullFieldHandler(b[0]);
}
else
{
nullFieldHandlerFactory = (i, b, f, e) => new BitArrayNullFieldHandler(b.ToArray());
}
}
}
}
private bool IsVisualFoxPro(DbfHeader dbfHeader)
{
return(dbfHeader.Type == DbfType.VisualFoxPro || dbfHeader.Type == DbfType.VisualFoxProVar || dbfHeader.Type == DbfType.VisualFoxProAutoInc);
}
