GXT

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Revision as of 19:51, 5 February 2009 by Aschratt (talk | contribs) (CRC32 Calculation)
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A GXT file contains almost all text that are displayed on the screen of GTA2 and above. The files are located in the text folder. An entire list of all entries between GTA3 and VCS is available with Sanny Builder. A list for GTA4 is available here.

File Stub

Each GXT-File can contain certain tables with subtables and entries. The entries are stored in ASCII standart. Just some special characters got some different bitsets.

GTA San Andreas / GTA IV Format

Header

The header contains data about the tables and their subtables.

INT32   - 4b   - Version? (Always 0x080004)
CHAR[4] - 4b   - TABL

Table Block

The Table Block contains data about the subtables and their offsets.

INT32   - 4b   - Blocksize

//Array of [Blocksize / 12 Entries]
CHAR[8] - 8b   - Subtablename
INT32   - 4b   - Offset

The Offset of the subtable points to an 8-byte Char Array with the subtable's name, followed by TKEY. For the MAIN Table this points directly to TKEY!

TKEY and TDAT

TKEY

The TKEY Block of an subtable contains the CRC32-values of the entrytitles. The game calculates the CRC32-value out of a given string and checks if they exist in the GXT.

CHAR[4] - 4b   - TKEY
INT32   - 4b   - Blocksize

//Array of [Blocksize / 8]
INT32   - 4b   - Entryoffset
INT32   - 4b   - CRC32 (Entrytitle)

The TKEY block is directly followed by the TDAT Block which contains the contents of the entries. The Entryoffset is relative to the TDAT + 4 offset.

TDAT

CHAR[4] - 4b   - TDAT
INT32   - 4b   - Blocksize

From here the Entryoffset of each entry points to the content. The content can have different size. However it always ends in '\0'! For Example "Hello!" needs to be "Hello!\0" here and this gives a size of 6 bytes. If this is the 1st content in TDAT the next got an offset of 0x06!

Special Characters

Here is a list of special characters for german language sets and their UINT8 Values:

Character Value
Ä 131
ä 154
Ö 145
ö 168
Ü 149
ü 172
ß 150

CRC32 Calculation

Here is a simple CRC32 calculation class written in C++: