/// <summary>
/// Reads a record using the previous data available.
/// TPS uses a stupid ( prossesing costly ) method to save space. It copies data from the last record if possible
/// </summary>
/// <param name="previous"></param>
/// <param name="pageDataRandomAccess"></param>
public TPSRecord(ref TPSRecord previous, ref RandomAccess pageDataRandomAccess)
{
//the flag tells us what data we should be copying
_flags = pageDataRandomAccess.leByte();
if ((_flags & 0x80) != 0)
{
_recordLength = pageDataRandomAccess.leShort();
}
else
{
_recordLength = previous.RecordLength;
}
if ((_flags & 0x40) != 0)
{
_headerLength = pageDataRandomAccess.leShort();
}
else
{
_headerLength = previous.HeaderLength;
}
//The last part tells us how much actual record data we should copy
int copy = _flags & 0x3F;
_data = new byte[_recordLength];
try {
Buffer.BlockCopy(previous.RecordData, 0, _data, 0, copy);
Buffer.BlockCopy(pageDataRandomAccess.leBytes(_recordLength - copy), 0, _data, copy, (_recordLength - copy));
//We may have to check if we pulled enough bytes from the pageDataRA, incase we hit the end prematurely
} catch (Exception ex) {
throw new Exception("When reading " + (_recordLength - copy) + " bytes of TpsRecord");
}
//
buildHeader();
}
/// <summary>
/// Gets data from the page
/// If the page is compressed, it will uncompress it and return it.
/// </summary>
/// <returns></returns>
private byte[] GetData()
{
//set our Randomaccess to the start of this page
RandomAccess ra = RandomAccess.GetInstance();
byte[] pageData;
ra.jumpAbs(addr);
ra.jumpRelative(13); //skip the header
//pull the page data
//This really shouldn't be very big.. on my files it was about 8kb
//If the file is using compression... uncompress it
if ((pageSize != pageSizeUncompressed) && (flags == 0))
{
try {
pageData = ra.deRle(pageSize - 13);
} catch (Exception ex) {
throw new Exception("Bad RLE DataBlock ( compressed: " + pageSize + " uncompressed: " + pageSizeUncompressed + " Page Address: " + addr + "Record Count: " + recordCount.ToString() + "): ", ex);
}
}
else
{
pageData = ra.leBytes(pageSize - 13);
}
return(pageData);
}
public TPSRecord(ref RandomAccess pageDataRandomAccess)
{
_flags = pageDataRandomAccess.leByte();
if ((_flags & 0xC0) != 0xC0)
{
throw new Exception("Can't construct a TpsRecord without record lengths");
}
_recordLength = pageDataRandomAccess.leShort();
_headerLength = pageDataRandomAccess.leShort();
_data = pageDataRandomAccess.leBytes(_recordLength); //read all of the data into a buffer.
//
buildHeader();
}
public object parseField(int type, int ofs, int len, TableField field, RandomAccess ra)
{
ra.jumpAbs(ofs);
switch (type)
{
case 1:
// byte
assertEqual(1, len);
return(ra.leByte());
case 2:
// short
assertEqual(2, len);
return(ra.leShort());
case 3:
// unsigned short
assertEqual(2, len);
return(ra.leUShort());
case 4:
// Date, mask encoded.
long date = ra.leULong();
if (date != 0)
{
long years = (date & 0xFFFF0000) >> 16;
long months = (date & 0x0000FF00) >> 8;
long days = (date & 0x000000FF);
return(new DateTime((int)years, (int)months, (int)days));
}
else
{
return(null);
}
case 5:
//
// Time, mask encoded.
// So far i've only had values with hours and minutes
// but no seconds or milliseconds so I've no way of
// knowing how to decode these.
//
//TODO: Fix the time here based on decaseconds
int time = ra.leLong();
int mins = (time & 0x00FF0000) >> 16;
int hours = (time & 0x7F000000) >> 24;
//
return(hours + " " + mins); //
case 6:
// Long
assertEqual(4, len);
return(ra.leLong());
case 7:
// Unsigned Long
assertEqual(4, len);
return(ra.leULong());
case 8:
// Float
assertEqual(4, len);
return(ra.leFloat());
case 9:
// Double
assertEqual(8, len);
return(ra.leDouble());
case 0x0A:
// BCD encoded.
return(ra.binaryCodedDecimal(len, field.BcdLengthOfElement, field.BcdDigitsAfterDecimalPoint));
case 0x12:
// Fixed Length String
return(ra.fixedLengthString(len));
case 0x13:
return(ra.zeroTerminatedString());
case 0x14:
return(ra.pascalString());
case 0x16:
// Group (an overlay on top of existing data, can be anything).
return(ra.leBytes(len));
default:
throw new Exception("Unsupported type " + type + " (" + len + ")");
}
}
