internal const int RESERVED_INDEX = 12; // 12-31
/**
* Constructs a DBFHeader, read the data from file <br>
* You need to supply an open file handle to read from
* @param ff open file handle for read access
*/
internal DBFHeader(java.io.RandomAccessFile ff) //throws tinySQLException
{
try
{
ff.seek(FLAG_INDEX);
file_type = Utils.fixByte(ff.readByte());
// get the last update date
file_update_year = Utils.fixByte(ff.readByte());
file_update_month = Utils.fixByte(ff.readByte());
file_update_day = Utils.fixByte(ff.readByte());
// a byte array to hold little-endian long data
//
byte[] b = new byte[4];
// read that baby in...
//
ff.readFully(b);
// convert the byte array into a long (really a double)
// 4-7 number of records
numRecords = (int)Utils.vax_to_long(b);
// a byte array to hold little-endian short data
//
b = new byte[2];
// get the data position (where it starts in the file)
// 8-9 Length of header
ff.readFully(b);
headerLength = Utils.vax_to_short(b);
// find out the length of the data portion
// 10-11 Length of Record
ff.readFully(b);
recordLength = Utils.vax_to_short(b);
// calculate the number of fields
//
numFields = (int)(headerLength - 33) / 32;
// skip the next 20 bytes - looks like this is not needed...
//ff.skipBytes(20);
// 12-31 reserved
Utils.log("HEADER=" + this.toString());
}
catch (Exception e)
{
throw new TinySQLException(e.getMessage());
}
}
/**
* Reading a column definition from file<br>
* @param ff file handle (correctly positioned)
* @param iCol index starts with 1
* @param locn offset to the current column
* @return struct with column info
*/
internal static TsColumn readColdef(java.io.RandomAccessFile ff, String tableName, int iCol, int locn) //throws tinySQLException
{
try
{
// seek the position of the field definition data.
// This information appears after the first 32 byte
// table information, and lives in 32 byte chunks.
//
ff.seek((iCol - 1) * 32 + 32);
// get the column name into a byte array
//
byte[] b = new byte[11];
ff.readFully(b);
// convert the byte array to a String
// Seek first 0x00 occurence and strip array after that
//
// some C-implementations do not set the remaining bytes
// after the name to 0x00, so we have to correct this.
//bool clear = false;
int i = 0;
while ((i < 11) && (b[i] != 0))
{
i++;
}
while (i < 11)
{
b[i] = 0;
i++;
}
String colName = (new java.lang.StringJ(b, Utils.encode)).trim();
// read in the column type which follows the 11 byte column name
//
byte[] c = new byte[1];
c[0] = ff.readByte();
String ftyp = new java.lang.StringJ(c, Utils.encode);
// skip four bytes
//
ff.skipBytes(4);
// get field length and precision which are in the two bytes following
// the column type.
//
short flen = Utils.fixByte(ff.readByte()); // 16
short fdec = Utils.fixByte(ff.readByte()); // 17
if (ftyp.equals("N") & fdec == 0)
{
ftyp = "I";
}
// bytes 18 - 31 are reserved
// create a new tsColumn object and assign it the
// attributes of the current field
//
if (TinySQLGlobals.DEBUG)
{
java.lang.SystemJ.outJ.println("Try and create tsColumn for " + colName);
}
TsColumn column = new TsColumn(colName);
/*
* The column type is now given as java.sql.Types constant
*/
column.type = typeToSQLType(ftyp);
column.size = flen;
column.decimalPlaces = fdec;
column.position = locn + 1; // set the field position to the current
column.tableName = tableName;
return(column);
}
catch (Exception e)
{
throw new TinySQLException(e.getMessage());
}
}
