const std = #import("std");

const stdin: FileDescriptor = 0;
const stdout: FileDescriptor = 1;
const stderr: FileDescriptor = 2;

const FileDescriptor = s32;

const ProtectionFlags = struct(u32) {
    read: bool,
    write: bool,
    execute: bool,
};

const MapFlags = struct(u32){
    shared: bool,
    private: bool,
    reserved: u2 = 0,
    fixed: bool,
    anonymous: bool,
};

const get_protection_flags = fn(flags: std.os.ProtectionFlags) ProtectionFlags {
    return ProtectionFlags{
        .read = flags.read,
        .write = flags.write,
        .execute = flags.execute,
    };
}

const get_map_flags = fn(flags: std.os.MapFlags) MapFlags{
    return MapFlags{
        .shared = false,
        .private = true,
        .fixed = false,
        .anonymous = true,
    };
}

const mmap = fn(address: ?[&]u8, length: usize, protection_flags: ProtectionFlags, map_flags: MapFlags, fd: s32, offset: u64) usize {
    const result = #syscall(9, #cast(address), length, #cast(protection_flags), #cast(map_flags), fd, offset);
    return result;
}

const munmap = fn(bytes_ptr: [&]const u8, bytes_len: usize) usize {
    const result = #syscall(11, #cast(bytes_ptr), bytes_len);
    return result;
}

const readlink = fn(file_path: [&:0]const u8, bytes_ptr: [&]u8, bytes_len: usize) usize {
    const result = #syscall(89, #cast(file_path), #cast(bytes_ptr), bytes_len);
    return result;
}

const unwrapSyscall = fn(syscall_result: usize) ?usize {
    const signed_syscall_result: ssize = #cast(syscall_result);
    if (signed_syscall_result >= 0) {
        return syscall_result;
    } else {
        return null;
    }
}