A PHP lib for read & write GTAV GXT2 format files.

gxt2.inc.php

<?php
/**
 * GXT2 file reader and writer
 *
 * @package GXT2
 * @version 1.0.0
 * @author Akkariin
 * @license MIT
 * @link https://github.com/kasuganosoras/
 * @example
 *   require_once "gxt2.inc.php";
 *   $gxt2 = new GXT2("global.gxt2");
 *   $data = $gxt2->Load();
 *   if ($data) {
 *      $data["ZERODREAM"] = "ZERODREAM233";
 *      $newGxt2 = new GXT2("global2.gxt2");
 *      $newGxt2->Save($data);
 *   }
 */
class GXT2
{

    private $file;

    /**
     * GXT2 constructor.
     * @param $file
     */
    public function __construct($file)
    {
        $this->file = fopen($file, "rw+");
    }

    /**
     * GXT2 destructor
     */
    public function __destruct()
    {
        fclose($this->file);
    }

    /**
     * Load GXT2 file
     * @return array|void
     * @throws Exception
     */
    public function Load()
    {
        $head = $this->ReadUInt32();
        if ($head !== 1196971058) {
            throw new Exception("Invalid GXT2 file");
            return;
        }
        $entryCount = unpack("V", fread($this->file, 4))[1];
        $textEntries = [];
        for ($i = 0; $i < $entryCount; $i++) {
            $hash = $this->ReadUInt32();
            $offset = $this->ReadUInt32();
            $textEntries[] = [
                "hash" => $hash,
                "offset" => $offset
            ];
        }
        $gxt2 = $this->ReadUInt32();
        if ($gxt2 !== 1196971058) {
            throw new Exception("Invalid GXT2 file");
            return;
        }
        $endPos = $this->ReadUInt32();
        $textList = [];
        foreach ($textEntries as $entry) {
            fseek($this->file, $entry["offset"]);
            $text = "";
            while (ftell($this->file) < $endPos) {
                $char = fread($this->file, 1);
                if ($char === "\0") {
                    break;
                }
                $text .= $char;
            }
            $textList[$entry["hash"]] = $text;
        }
        return $textList;
    }

    /**
     * Save GXT2 file
     * @param $textList
     */
    public function Save($textList)
    {
        $newTextList = [];
        foreach ($textList as $hash => $text) {
            if (!is_int($hash)) {
                $hash = $this->GetHashKey($hash);
            }
            $newTextList[$hash] = $text;
        }
        $textList = $newTextList;
        $entryCount = count($textList);
        $offset = 16 + ($entryCount * 8);
        $datas = [];
        fwrite($this->file, pack("V", 1196971058));
        fwrite($this->file, pack("V", $entryCount));
        foreach ($textList as $hash => $text) {
            fwrite($this->file, pack("V", $hash));
            fwrite($this->file, pack("V", $offset));
            $datas[] = [
                "hash" => $hash,
                "text" => $text . "\0"
            ];
            $offset += strlen($text) + 1;
        }
        fwrite($this->file, pack("V", 1196971058));
        fwrite($this->file, pack("V", $offset));
        foreach ($datas as $data) {
            fwrite($this->file, $data["text"]);
        }
    }

    /**
     * Read UInt32
     * @return mixed
     */
    private function ReadUInt32()
    {
        return unpack("V", fread($this->file, 4))[1];
    }

    /**
     * Get hash key
     * @param $name
     * @param bool $format
     * @return int|string
     */
    private function GetHashKey($name, $format = false)
    {
        $num = 0;
        $byte = unpack('C*', mb_convert_encoding($name, 'UTF-8', 'auto'));
        for ($i = 1; $i <= count($byte); $i++) {
            $num += $byte[$i];
            $num += $num << 10;
            $num &= 0xFFFFFFFF;
            $num ^= $num >> 6;
        }
        $num += $num << 3;
        $num &= 0xFFFFFFFF;
        $num ^= $num >> 11;
        $result = ($num + ($num << 15));
        $result &= 0xFFFFFFFF;
        if ($result > 2147483647) {
            $result -= 4294967296;
        }
        return $format ? sprintf("0x%08X", $result) : $result;
    }
}