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Valid dBASE for Windows table file, bits 0-2 indicate version number: 3 for dBASE Level 5, 4 for dBASE Level 7.
Bit 3 and bit 7 indicate presence of a dBASE IV or dBASE for Windows memo file;
bits 4-6 indicate the presence of a dBASE IV SQL table;
bit 7 indicates the presence of any .DBT memo file (either a dBASE III PLUS type or a dBASE IV or dBASE for Windows memo file).
The first byte of the DBF file determines the xbase file version
76543210
00000000
| - True if any memo file
| - True if Version 4 memo file
|| - True for both V3 and V4 files
00000011 - Could be a version III or version IV file, lib defaults to IV
10000011 - Version III with memo
10001011 - Version IV with memo
Logic for checking for which version
3 bit 4 not set, bit 5&6 set, if bit 0 set and bit 3 not set, then V3
4 bit 4 not set, bit 5&6 set, if bit 0 set and bit 3 set
5 bit 4 not set, bit 5&6 set, if bit 0 set and bit 3 set
>=7 bit 4 set
bit 0 bit 3 bit 4 bit 5 bit 6
V III Optional 0 0 1 1 No field type F
V IV Optional if bit0 then 1 0 1 1 Supports field type F
V V Optional if bit0 then 1 0 1 1 Supports field type F
V VII ? ? 1 0 0
pseudocode logic
if not bit 4, and bit 5 and bit 6
{
if V4 compiled in, if not (bit0 and not bit3) return V4
else
if V3 compiled in and not bit3, and not prod mdx, return V3
}
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