SA-MP's GPCI function implementation in GO and PHP

gpci.go

// https://github.com/Renegade334/gpci-js/blob/master/src/index.ts

package main

import (
	"crypto/sha1"
	"encoding/binary"
	"encoding/hex"
	"fmt"
	"os/user"
	"path/filepath"
	"strings"
)

func GPCI(input string) string {
	GPCI_SBOX := []byte{
		0, 4, 8, 12, 4, 5, 9, 13, 8, 9, 10, 14, 12, 13, 14, 15,
		64, 68, 72, 76, 68, 69, 73, 77, 72, 73, 74, 78, 76, 77, 78, 79,
		128, 132, 136, 140, 132, 133, 137, 141, 136, 137, 138, 142, 140, 141, 142, 143,
		192, 196, 200, 204, 196, 197, 201, 205, 200, 201, 202, 206, 204, 205, 206, 207,
		64, 68, 72, 76, 68, 69, 73, 77, 72, 73, 74, 78, 76, 77, 78, 79,
		80, 84, 88, 92, 84, 85, 89, 93, 88, 89, 90, 94, 92, 93, 94, 95,
		144, 148, 152, 156, 148, 149, 153, 157, 152, 153, 154, 158, 156, 157, 158, 159,
		208, 212, 216, 220, 212, 213, 217, 221, 216, 217, 218, 222, 220, 221, 222, 223,
		128, 132, 136, 140, 132, 133, 137, 141, 136, 137, 138, 142, 140, 141, 142, 143,
		144, 148, 152, 156, 148, 149, 153, 157, 152, 153, 154, 158, 156, 157, 158, 159,
		160, 164, 168, 172, 164, 165, 169, 173, 168, 169, 170, 174, 172, 173, 174, 175,
		224, 228, 232, 236, 228, 229, 233, 237, 232, 233, 234, 238, 236, 237, 238, 239,
		192, 196, 200, 204, 196, 197, 201, 205, 200, 201, 202, 206, 204, 205, 206, 207,
		208, 212, 216, 220, 212, 213, 217, 221, 216, 217, 218, 222, 220, 221, 222, 223,
		224, 228, 232, 236, 228, 229, 233, 237, 232, 233, 234, 238, 236, 237, 238, 239,
		240, 244, 248, 252, 244, 245, 249, 253, 248, 249, 250, 254, 252, 253, 254, 255,
	}

	hash := sha1.Sum([]byte(input))
	swappedHash := make([]byte, 20)

	for i := 0; i < 5; i++ {
		binary.BigEndian.PutUint32(swappedHash[i*4:], binary.LittleEndian.Uint32(hash[i*4:]))
	}

	byteArray := make([]byte, 20)
	for i := 0; i < len(swappedHash); i++ {
		byteArray[i] = GPCI_SBOX[swappedHash[i]]
	}

	result := strings.TrimLeft(hex.EncodeToString(byteArray), "0")
	return strings.ToUpper(result)
}

func main() {
	usr, err := user.Current()
	if err != nil {
		panic(err)
	}

	GTASanAndreasUserFiles := filepath.Join(usr.HomeDir, "Documents", "GTA San Andreas User Files")
	result := GPCI(GTASanAndreasUserFiles[4:])

	// fmt.Println("GTA San Andreas User Files Path:", GTASanAndreasUserFiles)
	fmt.Println("Your GPCI hash is:", result)

	fmt.Println("Press Enter to continue...")
	fmt.Scanln()
}

gpci.php

<?php
// https://github.com/Renegade334/gpci-js/blob/master/src/index.ts

function GPCI($input) {
    $GPCI_SBOX = [
        0,   4,   8,   12,  4,   5,   9,   13,  8,   9,   10,  14,  12,  13,  14,  15,
        64,  68,  72,  76,  68,  69,  73,  77,  72,  73,  74,  78,  76,  77,  78,  79,
        128, 132, 136, 140, 132, 133, 137, 141, 136, 137, 138, 142, 140, 141, 142, 143,
        192, 196, 200, 204, 196, 197, 201, 205, 200, 201, 202, 206, 204, 205, 206, 207,
        64,  68,  72,  76,  68,  69,  73,  77,  72,  73,  74,  78,  76,  77,  78,  79,
        80,  84,  88,  92,  84,  85,  89,  93,  88,  89,  90,  94,  92,  93,  94,  95,
        144, 148, 152, 156, 148, 149, 153, 157, 152, 153, 154, 158, 156, 157, 158, 159,
        208, 212, 216, 220, 212, 213, 217, 221, 216, 217, 218, 222, 220, 221, 222, 223,
        128, 132, 136, 140, 132, 133, 137, 141, 136, 137, 138, 142, 140, 141, 142, 143,
        144, 148, 152, 156, 148, 149, 153, 157, 152, 153, 154, 158, 156, 157, 158, 159,
        160, 164, 168, 172, 164, 165, 169, 173, 168, 169, 170, 174, 172, 173, 174, 175,
        224, 228, 232, 236, 228, 229, 233, 237, 232, 233, 234, 238, 236, 237, 238, 239,
        192, 196, 200, 204, 196, 197, 201, 205, 200, 201, 202, 206, 204, 205, 206, 207,
        208, 212, 216, 220, 212, 213, 217, 221, 216, 217, 218, 222, 220, 221, 222, 223,
        224, 228, 232, 236, 228, 229, 233, 237, 232, 233, 234, 238, 236, 237, 238, 239,
        240, 244, 248, 252, 244, 245, 249, 253, 248, 249, 250, 254, 252, 253, 254, 255
    ];

    $hash = sha1($input, true);
    $swapped_hash = '';
    
    for ($i = 0; $i < strlen($hash); $i += 4) $swapped_hash .= strrev(substr($hash, $i, 4));

    $byte_array = '';
    for ($i = 0; $i < strlen($swapped_hash); $i++) $byte_array .= chr($GPCI_SBOX[ord($swapped_hash[$i])]);

    $result = ltrim(bin2hex($byte_array), '0');

    return strtoupper($result);
}

$input    = substr($_GET['input'], 4) ?? null;
$result   = $input ? GPCI($input) : null;
$our_gpci = "94F988DEDE9DEE49EDCDACDFA5840CA45F48CEDC";

echo "Input: $input<br>";
echo "The GPCI hash for the input is: $result<br>";

echo "Our GPCI: $our_gpci<br>";
echo "Same? " . (($result === $our_gpci) ? 'true' : 'false');
?>