src/test/run-pass/multiple-reprs.rs

// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

#![allow(dead_code)]

use std::mem::{size_of, align_of};
use std::os::raw::c_int;

// The two enums that follow are designed so that bugs trigger layout optimization.
// Specifically, if either of the following reprs used here is not detected by the compiler,
// then the sizes will be wrong.

#[repr(C, u8)]
enum E1 {
    A(u8, u16, u8),
    B(u8, u16, u8)
}

#[repr(u8, C)]
enum E2 {
    A(u8, u16, u8),
    B(u8, u16, u8)
}

// Check that repr(int) and repr(C) are in fact different from the above

#[repr(u8)]
enum E3 {
    A(u8, u16, u8),
    B(u8, u16, u8)
}

#[repr(u16)]
enum E4 {
    A(u8, u16, u8),
    B(u8, u16, u8)
}

#[repr(u32)]
enum E5 {
    A(u8, u16, u8),
    B(u8, u16, u8)
}

#[repr(u64)]
enum E6 {
    A(u8, u16, u8),
    B(u8, u16, u8)
}

#[repr(C)]
enum E7 {
    A(u8, u16, u8),
    B(u8, u16, u8)
}

// From pr 37429

#[repr(C,packed)]
pub struct p0f_api_query {
    pub magic: u32,
    pub addr_type: u8,
    pub addr: [u8; 16],
}

pub fn main() {
    assert_eq!(size_of::<E1>(), 8);
    assert_eq!(size_of::<E2>(), 8);
    assert_eq!(size_of::<E3>(), 6);
    assert_eq!(size_of::<E4>(), 8);
    assert_eq!(size_of::<E5>(), align_size(10, align_of::<u32>()));
    assert_eq!(size_of::<E6>(), align_size(14, align_of::<u64>()));
    assert_eq!(size_of::<E7>(), align_size(6 + size_of::<c_int>(), align_of::<c_int>()));
    assert_eq!(size_of::<p0f_api_query>(), 21);
}

fn align_size(size: usize, align: usize) -> usize {
    if size % align != 0 {
        size + (align - (size % align))
    } else {
        size
    }
}