Task 363: .LUA File Format

The .LUA file format is the standard extension for Lua programming language source code files, which are plain text files containing Lua code. The specifications for the Lua language syntax and semantics are defined in the Lua Reference Manual.

1. List of all the properties of this file format intrinsic to its file system.

Since .LUA files are plain text files, they do not have format-specific binary properties. The intrinsic properties are the standard file attributes managed by the file system (e.g., on Unix-like systems via the stat structure; similar equivalents exist on Windows and other OSes):

• File name
• File size (in bytes)
• Permissions (mode, including read/write/execute for owner, group, and others, and file type)
• Inode number
• Owner user ID (UID)
• Owner group ID (GID)
• Device ID
• Number of hard links
• Last access time (atime)
• Last modification time (mtime)
• Last status change time (ctime)
• Creation time (birthtime/btime, if supported by the file system)

Find two direct download links for files of format .LUA.

https://raw.githubusercontent.com/lua/lua/master/lopcodes.lua

https://raw.githubusercontent.com/lua/lua/master/lparser.lua

Write a ghost blog embedded html javascript that allows a user to drag n drop a file of format .LUA and it will dump to screen all these properties.

Here is an embeddable HTML + JavaScript snippet suitable for a Ghost blog post (or any HTML page). It creates a drag-and-drop zone that accepts a .LUA file and displays the available file properties on screen. Note that in a browser context, only a subset of properties is accessible via the File API (e.g., no owner, permissions, or inode due to security restrictions).

1. Write a python class that can open any file of format .LUA and decode read and write and print to console all the properties from the above list.

Since .LUA is plain text, no decoding is required. The class uses os.stat to read the properties (write support for properties like permissions or times can be added via os.chmod or os.utime, but here "write" is interpreted as the ability to update select properties like modification time). The class opens the file path, reads the properties, and prints them to console.

import os
import time

class LuaFileHandler:
    def __init__(self, filepath):
        self.filepath = filepath

    def read_properties(self):
        st = os.stat(self.filepath)
        properties = {
            'File name': os.path.basename(self.filepath),
            'File size (in bytes)': st.st_size,
            'Permissions (mode)': oct(st.st_mode),
            'Inode number': st.st_ino,
            'Owner user ID (UID)': st.st_uid,
            'Owner group ID (GID)': st.st_gid,
            'Device ID': st.st_dev,
            'Number of hard links': st.st_nlink,
            'Last access time': time.ctime(st.st_atime),
            'Last modification time': time.ctime(st.st_mtime),
            'Last status change time': time.ctime(st.st_ctime),
            'Creation time': time.ctime(st.st_birthtime) if hasattr(st, 'st_birthtime') else 'Not available'
        }
        return properties

    def print_properties(self):
        props = self.read_properties()
        for key, value in props.items():
            print(f"{key}: {value}")

    # Example write method to update modification time (as an illustration of 'write')
    def write_modification_time(self, new_time=None):
        if new_time is None:
            new_time = time.time()
        os.utime(self.filepath, (new_time, new_time))

# Usage example:
# handler = LuaFileHandler('example.lua')
# handler.print_properties()
# handler.write_modification_time()

1. Write a java class that can open any file of format .LUA and decode read and write and print to console all the properties from the above list.

Since .LUA is plain text, no decoding is required. The class uses java.nio.file to read the properties (write support for properties like permissions or times can be added via Files.setPosixFilePermissions or Files.setLastModifiedTime, but here "write" is interpreted as the ability to update select properties like modification time). The class opens the file path, reads the properties, and prints them to console.

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.attribute.BasicFileAttributes;
import java.nio.file.attribute.FileTime;
import java.nio.file.attribute.PosixFileAttributes;
import java.nio.file.attribute.PosixFilePermissions;
import java.nio.file.LinkOption;

public class LuaFileHandler {
    private final Path path;

    public LuaFileHandler(String filepath) {
        this.path = Paths.get(filepath);
    }

    public void printProperties() throws IOException {
        BasicFileAttributes basicAttrs = Files.readAttributes(path, BasicFileAttributes.class);
        PosixFileAttributes posixAttrs = Files.readAttributes(path, PosixFileAttributes.class, LinkOption.NOFOLLOW_LINKS);

        System.out.println("File name: " + path.getFileName());
        System.out.println("File size (in bytes): " + basicAttrs.size());
        System.out.println("Permissions (mode): " + PosixFilePermissions.toString(posixAttrs.permissions()));
        System.out.println("Inode number: " + basicAttrs.fileKey());  // Approximation, as inode may vary by FS
        System.out.println("Owner user ID (UID): " + posixAttrs.owner());
        System.out.println("Owner group ID (GID): " + posixAttrs.group());
        System.out.println("Device ID: Not directly available");
        System.out.println("Number of hard links: " + posixAttrs.size());  // Not standard, approximation
        System.out.println("Last access time: " + basicAttrs.lastAccessTime());
        System.out.println("Last modification time: " + basicAttrs.lastModifiedTime());
        System.out.println("Last status change time: Not directly available");
        System.out.println("Creation time: " + basicAttrs.creationTime());
    }

    // Example write method to update modification time (as an illustration of 'write')
    public void writeModificationTime(long newTimeMillis) throws IOException {
        FileTime newTime = FileTime.fromMillis(newTimeMillis);
        Files.setLastModifiedTime(path, newTime);
    }

    // Usage example:
    // public static void main(String[] args) throws IOException {
    //     LuaFileHandler handler = new LuaFileHandler("example.lua");
    //     handler.printProperties();
    //     handler.writeModificationTime(System.currentTimeMillis());
    // }
}

1. Write a javascript class that can open any file of format .LUA and decode read and write and print to console all the properties from the above list.

Since .LUA is plain text, no decoding is required. This is for Node.js (as browser JS can't access full file system properties). The class uses fs.stat to read the properties (write support for properties like permissions or times can be added via fs.chmod or fs.utime, but here "write" is interpreted as the ability to update select properties like modification time). The class opens the file path, reads the properties, and prints them to console.

const fs = require('fs');
const path = require('path');

class LuaFileHandler {
  constructor(filepath) {
    this.filepath = filepath;
  }

  printProperties() {
    const st = fs.statSync(this.filepath);
    console.log('File name: ' + path.basename(this.filepath));
    console.log('File size (in bytes): ' + st.size);
    console.log('Permissions (mode): ' + st.mode.toString(8));
    console.log('Inode number: ' + st.ino);
    console.log('Owner user ID (UID): ' + st.uid);
    console.log('Owner group ID (GID): ' + st.gid);
    console.log('Device ID: ' + st.dev);
    console.log('Number of hard links: ' + st.nlink);
    console.log('Last access time: ' + st.atime);
    console.log('Last modification time: ' + st.mtime);
    console.log('Last status change time: ' + st.ctime);
    console.log('Creation time: ' + st.birthtime);
  }

  // Example write method to update modification time (as an illustration of 'write')
  writeModificationTime(newTime = Date.now()) {
    fs.utimesSync(this.filepath, newTime / 1000, newTime / 1000);
  }
}

// Usage example:
// const handler = new LuaFileHandler('example.lua');
// handler.printProperties();
// handler.writeModificationTime();

1. Write a c class that can open any file of format .LUA and decode read and write and print to console all the properties from the above list.

Since .LUA is plain text, no decoding is required. This is a C++ class (as pure C doesn't have classes; the task likely implies C++ for "class"). The class uses stat to read the properties (write support for properties like permissions or times can be added via chmod or utimes, but here "write" is interpreted as the ability to update select properties like modification time). The class opens the file path, reads the properties, and prints them to console.

#include <iostream>
#include <string>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <ctime>

class LuaFileHandler {
private:
    std::string filepath;

public:
    LuaFileHandler(const std::string& fp) : filepath(fp) {}

    void printProperties() {
        struct stat st;
        if (stat(filepath.c_str(), &st) != 0) {
            std::cerr << "Error accessing file properties." << std::endl;
            return;
        }

        std::cout << "File name: " << filepath.substr(filepath.find_last_of("/\\") + 1) << std::endl;
        std::cout << "File size (in bytes): " << st.st_size << std::endl;
        std::cout << "Permissions (mode): " << std::oct << st.st_mode << std::endl;
        std::cout << "Inode number: " << st.st_ino << std::endl;
        std::cout << "Owner user ID (UID): " << st.st_uid << std::endl;
        std::cout << "Owner group ID (GID): " << st.st_gid << std::endl;
        std::cout << "Device ID: " << st.st_dev << std::endl;
        std::cout << "Number of hard links: " << st.st_nlink << std::endl;
        std::cout << "Last access time: " << std::ctime(&st.st_atime);
        std::cout << "Last modification time: " << std::ctime(&st.st_mtime);
        std::cout << "Last status change time: " << std::ctime(&st.st_ctime);
        std::cout << "Creation time: Not available in standard stat" << std::endl;
    }

    // Example write method to update modification time (as an illustration of 'write')
    void writeModificationTime(time_t newTime = time(nullptr)) {
        struct timespec times[2];
        times[0].tv_sec = newTime;
        times[0].tv_nsec = UTIME_OMIT;
        times[1].tv_sec = newTime;
        times[1].tv_nsec = 0;
        if (utimensat(AT_FDCWD, filepath.c_str(), times, 0) != 0) {
            std::cerr << "Error updating modification time." << std::endl;
        }
    }
};

// Usage example:
// int main() {
//     LuaFileHandler handler("example.lua");
//     handler.printProperties();
//     handler.writeModificationTime();
//     return 0;
// }