//! Prints files: `cat <file>...`.

#![no_std]
#![no_main]

extern crate libkos;

use libkos::fs::{FsError, Storage};
use libkos::println;

/// Where storage's buffer is mapped.
const STORAGE_BUF_VA: usize = 0x0180_0000;

fn cat(fs: &mut Storage, path: &str) -> Result<(), FsError> {
    let h = fs.open(path.as_bytes())?;
    let mut buf = [0u8; 4096];
    loop {
        let n = fs.read(h, &mut buf)?;
        libkos::io::write_bytes(&buf[..n]);
        if n < buf.len() {
            break;
        }
    }
    fs.close(h)
}

#[unsafe(no_mangle)]
extern "C" fn main() {
    let Some(mut fs) = libkos::start::storage().and_then(|ep| Storage::attach(ep, STORAGE_BUF_VA).ok()) else {
        println!("cat: no storage");
        return;
    };
    let mut any = false;
    for path in libkos::start::args().skip(1) {
        any = true;
        match cat(&mut fs, path) {
            Ok(()) => {}
            Err(FsError::NotFound) => println!("cat: {}: no such file", path),
            Err(_) => println!("cat: {}: cannot read", path),
        }
    }
    if !any {
        println!("usage: cat <file>...");
    }
}