src/test/run-pass/mir_fat_ptr.rs

   1 // Copyright 2015 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 // test that ordinary fat pointer operations work.
  12
  13 struct Wrapper<T: ?Sized>(u32, T);
  14
  15 struct FatPtrContainer<'a> {
  16     ptr: &'a [u8]
  17 }
  18
  19 fn fat_ptr_project(a: &Wrapper<[u8]>) -> &[u8] {
  20     &a.1
  21 }
  22
  23 fn fat_ptr_simple(a: &[u8]) -> &[u8] {
  24     a
  25 }
  26
  27 fn fat_ptr_via_local(a: &[u8]) -> &[u8] {
  28     let x = a;
  29     x
  30 }
  31
  32 fn fat_ptr_from_struct(s: FatPtrContainer) -> &[u8] {
  33     s.ptr
  34 }
  35
  36 fn fat_ptr_to_struct(a: &[u8]) -> FatPtrContainer {
  37     FatPtrContainer { ptr: a }
  38 }
  39
  40 fn fat_ptr_store_to<'a>(a: &'a [u8], b: &mut &'a [u8]) {
  41     *b = a;
  42 }
  43
  44 fn fat_ptr_constant() -> &'static str {
  45     "HELLO"
  46 }
  47
  48 fn main() {
  49     let a = Wrapper(4, [7,6,5]);
  50
  51     let p = fat_ptr_project(&a);
  52     let p = fat_ptr_simple(p);
  53     let p = fat_ptr_via_local(p);
  54     let p = fat_ptr_from_struct(fat_ptr_to_struct(p));
  55
  56     let mut target : &[u8] = &[42];
  57     fat_ptr_store_to(p, &mut target);
  58     assert_eq!(target, &a.1);
  59
  60     assert_eq!(fat_ptr_constant(), "HELLO");
  61 }