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xb:start

FRM Files

  • Constant size = 1990 bytes (RBSIZ_FILE)
  • Offsets are 1-based, not 0-based
  • Little-endian format
  • Rather good description at http://www.clicketyclick.dk/databases/xbase/format/frm.html up to the “data structures” part
  • Other info from the source of the public domain DBE package at http://www.the-oasis.net/ftpmaster.php3?content=ftputils.htm
  • Differences noted with above reference
    • Files start and end with “02 00”. They don't end with the array of data structures
    • There is no global 36-byte repeated structure but 25 12-byte Field structures and 1 24-byte Params structure, which defines, among other things, the group/subgroup expressions

Global structure

  • 01-02 Version = 02 00
  • 03-04 Offset: RBOFF_EXPSIZE = 3, Size: 2, contents: d2 00 = 210 (DBE: nExpSize)
  • 05-114 Offset: RBOFF_LENGTHS = 5, Size: RBSIZ_LENGTHS = 110, contents: 55 expression length values (DBE: cLengths)
  • 115-224 Offset: RBOFF_OFFSETS = 115, Size: RBSIZ_OFFSETS = 110, contents: 55 expression offset values (DBE: cOffsets)
  • 225-1664 Offset: RBOFF_EXPRS = 225, Size: RBSIZ_EXPRS = 1440, contents: 55 expression values (DBE: cExprs)
  • 1665-1964 Offset: RBOFF_FIELDS = 1665, Size: RBOFF_SIZE = 300, contents: n report fields (DBE: cFields). Different from the xbase info.
  • 1965-1988 Offset: RBOFF_PARAMS = 1965, Size: RBSIZ_PARAMS = 24, contents: report parameters ?. Different from the xbase info.
  • 1989-1990 Version = 02 00

Fields

This is the structure of one of the 25 12-byte fields blocks, called “data structure” in the xbase description

  • 1-2 RBOFF_FWIDTH = 1, “Report width”, Column width on report
  • 3-5 unused. “Pad1” and “Pad2”.
  • 6 RBOFF_TOTAL = 6, “Total”, (Y/N value). Compute a total on field
  • 7-8 RBOFF_FDEC = 7, “Decimal”,
  • 9-10 RBOFF_FCONTENT = 9, “Expression content”. Number of expression containing value in expression list
  • 11-12 RBOFF_FHEADER = 11, “Title expression no”. Number of expression containint header in expression list

Params

This is the contents of the 24-byte block at RBOFF_PARAMS:

  • 1-2 RBOFF_PGHDR = 1, Value = 00 00 = 0
  • 3-4 RBOFF_GRPEXP = 3, Value = 01 00 = 1 (DBE: aReport[RP_GROUPS][1][RG_TEXT])
  • 5-6 RBOFF_SUBEPXR = 5, Value = ff ff = -1 (DBE: aReport[RP_GROUPS][2][RG_TEXT])
  • 7-8 RBOFF_GRPHDR = 7, Value = 02 00 = 2 (DBE: aReport[RP_GROUPS][1][RG_HEADER])
  • 9-10 RBOFF_SUBHDR = 9, Value = ff ff = -1 (DBE: aReport[RP_GROUPS][2][RG_HEADER])
  • 11-12 RBOFF_PGWIDTH = 11, Value = 87 00 = 135 (DBE: aReport[RP_WIDTH])
  • 13-14 RBOFF_PGLINES = 13, Value = 32 00 = 50 (DBE: aReport[RP_LINES])
  • 15-16 RBOFF_LMARGIN = 15, Value = 01 00 = 1 (DBE: aReport[RP_LMARGIN])
  • 17-18 RBOFF_RMARGIN = 17, Value = 01 00 = 1 (DBE: aReport[RP_RMARGIN])
  • 19-20 RBOFF_COLCOUNT = 19, Value = 0a 00 = 10 (DBE: aReport[RP_COLCOUNT])
  • 21 RBOFF_DBLSPACE = 21, Value = 4e = 'N' (DBE: aReport[RP_DBLSPACE])
  • 22 RBOFF_SUMMARY = 22, Value = 4e = 'N' (DBE: aReport[RP_SUMMARY])
  • 23 RBOFF_AEJECT = 23, Value = 4e = 'N' (DBE: aReport[RP_GROUPS][1][RG_AEJECT]) Eject between groups ?
  • 24 RBOFF_OPTION = 24. Contains three bit values
    • bit 0: (DBE: aReport[RP_BEJECT])
    • bit 1: (DBE: aReport[RP_AEJECT])
    • bit 2: (DBE: aReport[RP_PLAIN])
xb/start.txt · Last modified: 2007/12/22 15:45 (external edit)