public void WriteHeader()
{
StreamSeek(_Stream, 0);
DBF_FILEHEADER_3 header = new DBF_FILEHEADER_3();
header.headerlength = (ushort)HeaderLength;
header.crypt = 0;
header.incomplete = 0;
DateTimeOffset now = DateTimeOffset.UtcNow;
header.lastupdate.yy = (byte)(now.Year - 1900);
header.lastupdate.mm = (byte)now.Month;
header.lastupdate.dd = (byte)now.Day;
header.recordcount = (ushort)RecordCount;
header.recordlength = (ushort)RecordLength;
header.version = (byte)(HasMemo ? Const.MAGIC_DBASE_DEFAULT_MEMO : Const.MAGIC_DBASE_DEFAULT);
header.unused_0 = 0;
for (int i = 0; i < 16; i++)
{
//header.unused[i] = 0;
}
byte[] bytes = Utility.StructureToPtr <DBF_FILEHEADER_3>(header);
StreamWrite(_Stream, bytes);
StreamSeek(_Stream, HeaderLength + RecordCount * RecordLength);
bytes = new byte[] { (byte)Const.CPM_TEXT_TERMINATOR };
StreamWrite(_Stream, bytes);
if (HasMemo)
{
_MemoFile.WriteHeader();
}
}
private static bool sanity_check(DBF_FILEHEADER_3 header)
{
bool ok = ((header.lastupdate.mm >= 1) && (header.lastupdate.mm <= 12)) &&
((header.lastupdate.dd >= 1) && (header.lastupdate.dd <= 31))
;
return(ok);
}
public bool Attach(Stream stream, string filename, bool read_header)
{
bool ok = (stream != null);
if (ok && read_header)
{
byte[] bytes = new byte[Marshal.SizeOf(typeof(Byte))];
ok = (bytes.Length == StreamRead(stream, bytes));
if (ok)
{
Byte version = bytes[0];
int len_header;
int len_field;
switch (version)
{
case Const.MAGIC_DBASE4:
case Const.MAGIC_DBASE4_MEMO:
len_header = Marshal.SizeOf(typeof(DBF_FILEHEADER_4));
len_field = Marshal.SizeOf(typeof(DBF_FILEFIELD_4));
break;
case Const.MAGIC_DBASE3:
case Const.MAGIC_DBASE3_MEMO:
case Const.MAGIC_DBASE3_MEMO_2:
case Const.MAGIC_FOXPRO:
default:
len_header = Marshal.SizeOf(typeof(DBF_FILEHEADER_3));
len_field = Marshal.SizeOf(typeof(DBF_FILEFIELD_3));
break;
}
bytes = new byte[len_header];
StreamSeek(stream, 0);
ok = (len_header == StreamRead(stream, bytes));
if (ok)
{
switch (version)
{
case Const.MAGIC_DBASE4:
case Const.MAGIC_DBASE4_MEMO:
{
DBF_FILEHEADER_4 header = Utility.PtrToStructure <DBF_FILEHEADER_4>(bytes);
_RecordCount = header.recordcount;
RecordLength = header.recordlength;
HeaderLength = header.headerlength;
ok = sanity_check(header);
break;
}
case Const.MAGIC_DBASE3:
case Const.MAGIC_DBASE3_MEMO:
case Const.MAGIC_DBASE3_MEMO_2:
case Const.MAGIC_FOXPRO:
default:
{
DBF_FILEHEADER_3 header = Utility.PtrToStructure <DBF_FILEHEADER_3>(bytes);
_RecordCount = header.recordcount;
RecordLength = header.recordlength;
HeaderLength = header.headerlength;
ok = sanity_check(header);
break;
}
}
if (ok)
{
if ((RecordCount == 0) && (RecordLength != 0))
{
_RecordCount = (stream.Length - HeaderLength) / RecordLength;
}
int fieldcount = (HeaderLength - (len_header + 1)) / len_field;
bytes = new byte[len_field];
for (int i = 0; i < fieldcount; i++)
{
ColumnInfo field;
StreamRead(stream, bytes);
if ((bytes[0] >= 0) && (bytes[0] <= (byte)' '))
{
break;
}
switch (version)
{
case Const.MAGIC_DBASE4:
case Const.MAGIC_DBASE4_MEMO:
{
DBF_FILEFIELD_4 item = Utility.PtrToStructure <DBF_FILEFIELD_4>(bytes);
DataType type = (DataType)Const.DataTypes.IndexOf(item.type);
field = new ColumnInfo()
{
Name = item.title, DataType = Convert.Type(type), Length = item.length, DecCount = item.deccount
};
break;
}
case Const.MAGIC_DBASE3:
case Const.MAGIC_DBASE3_MEMO:
case Const.MAGIC_DBASE3_MEMO_2:
case Const.MAGIC_FOXPRO:
default:
{
DBF_FILEFIELD_3 item = Utility.PtrToStructure <DBF_FILEFIELD_3>(bytes);
DataType type = (DataType)Const.DataTypes.IndexOf(item.type);
field = new ColumnInfo()
{
Name = item.title, DataType = Convert.Type(type), Length = item.length, DecCount = item.deccount
};
break;
}
}
Columns.Add(field);
}
}
}
}
}
if (ok)
{
_Stream = stream;
Filename = filename;
}
return(ok);
}
