San-Andreas-Roleplay-ES/crc32

SA-MP CRC32 Hash Calculator

A CRC32 hash calculator specifically for SA-MP 0.3DL files that computes checksums compatible with the algorithm used by San Andreas Multiplayer.

📋 Description

This project implements the SA-MP specific CRC32 algorithm to calculate hashes of .dff and .txd files used in SA-MP 0.3DL servers. The algorithm exactly replicates the GetFileCRC32Checksum function from the SA-MP source code.

What does it do?

• 🔍 Calculates CRC32 hashes compatible with SA-MP 0.3DL
• 📁 Processes .dff (3D models) and .txd (textures) files
• ✅ Verifies that files match expected hashes
• 🔄 Reads files in 1024-byte chunks (same as SA-MP)

🚀 Installation

Prerequisites

• Node.js (version 16 or higher)
• Yarn package manager

Initial Setup

# Clone the repository
git clone https://github.com/San-Andreas-Roleplay-ES/crc32.git
cd crc32

# Install dependencies
yarn install

# Compile TypeScript
yarn build

📦 Available Commands

# Install dependencies
yarn install

# Compile the TypeScript project
yarn build

# Run the project (after compiling)
yarn start

# Run in development mode (ts-node)
yarn dev

# Clean compiled files
yarn clean

📁 Project Structure

crc32/
├── src/
│   └── index.ts          # Main code with CRC32 algorithm
├── assets/               # Test files (.dff, .txd)
│   ├── cesar.dff
│   ├── cesar.txd
│   ├── fam1.dff
│   ├── fam1.txd
│   ├── wmyammo.dff
│   └── wmyammo.txd
├── package.json
├── tsconfig.json
└── README.md

🔧 Usage

Verify existing files

The script automatically verifies all files in the assets/ folder and compares their CRC32 hashes with expected values:

yarn start

Expected output:

✅ cesar.dff OK: expected 2F363354, got 2F363354
✅ cesar.txd OK: expected 4BCE378B, got 4BCE378B
✅ fam1.dff OK: expected 2CB8FD7E, got 2CB8FD7E
✅ fam1.txd OK: expected 4E76581E, got 4E76581E
✅ wmyammo.dff OK: expected 8EC07DC0, got 8EC07DC0
✅ wmyammo.txd OK: expected 27B61A89, got 27B61A89

✅ All hashes match!

Use as module

import { getSAMPCRC32 } from "./src/index";

// Calculate CRC32 of a file
const hash = await getSAMPCRC32("./assets/example.dff");
console.log(`CRC32 Hash: ${hash}`);

🔬 Algorithm

The project implements the exact SA-MP CRC32 algorithm:

// Based on the original SA-MP C++ code:
// Source: https://github.com/openmultiplayer/open.mp/blob/master/Server/Components/CustomModels/crc32.hpp
static uint32_t CRC32(uint32_t checksum, uint8_t* buffer, int length)
{
    checksum = ~checksum;
    while (length--)
    {
        checksum = crc32Table[(checksum ^ *buffer++) & 0xff] ^ (checksum >> 8);
    }
    return ~checksum;
}

Key Features:

• ✅ Uses the standard CRC32 table
• ✅ Processes files in 1024-byte chunks
• ✅ Correctly handles 32-bit unsigned numbers in JavaScript
• ✅ 100% compatible with SA-MP 0.3DL algorithm

🧪 Test Files

The files in assets/ are real SA-MP files with known hashes:

🤝 Contributing

1. Fork the project
2. Create a feature branch (git checkout -b feature/AmazingFeature)
3. Commit your changes (git commit -m 'Add some AmazingFeature')
4. Push to the branch (git push origin feature/AmazingFeature)
5. Open a Pull Request

📄 License

This project is under the MIT License. See the LICENSE file for more details.