#![no_std]
use turkos_os_syscall_abi::syscall_abi::Errno;
pub const VERSION: u64 = 2;
pub const EXIT: u64 = 3;
pub const ALLOC: u64 = 4;
pub const FREE: u64 = 5;
pub const PANIC_EXIT: i32 = 127;
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub enum Request {
    Exit(i32),
    Alloc { bytes: usize, alignment: usize },
    Free(u64),
}
pub fn compatible(required: u64, available: u64) -> Result<(), Errno> {
    if !matches!(required, 1 | 2) || !matches!(available, 1 | 2) || required > available {
        return Err(Errno::NoSys);
    }
    Ok(())
}
/// This separately named v2 wire contract does not extend the frozen v1
/// Dispatcher. It grants no owner, allocation or native SVC service by itself.
pub fn decode(version: u64, number: u64, arguments: [u64; 6]) -> Result<Request, Errno> {
    if version != VERSION {
        return Err(Errno::NoSys);
    }
    match number {
        EXIT => {
            let code = arguments[0] as i32;
            if code as i64 as u64 != arguments[0] {
                return Err(Errno::Overflow);
            }
            Ok(Request::Exit(code))
        }
        ALLOC => {
            let bytes = usize::try_from(arguments[0]).map_err(|_| Errno::Overflow)?;
            let alignment = usize::try_from(arguments[1]).map_err(|_| Errno::Overflow)?;
            if bytes == 0 || bytes > 4096 || !alignment.is_power_of_two() || alignment > 4096 {
                return Err(Errno::Invalid);
            }
            Ok(Request::Alloc { bytes, alignment })
        }
        FREE if arguments[0] != 0 => Ok(Request::Free(arguments[0])),
        FREE => Err(Errno::Invalid),
        _ => Err(Errno::NoSys),
    }
}