57 lines
1.7 KiB
Rust
57 lines
1.7 KiB
Rust
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// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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use std::slice;
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fn foo<T>(v: &[T]) -> Option<&[T]> {
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let mut it = v.iter();
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for _ in 0..5 {
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let _ = it.next();
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}
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Some(it.as_slice())
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}
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fn foo_mut<T>(v: &mut [T]) -> Option<&mut [T]> {
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let mut it = v.iter_mut();
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for _ in 0..5 {
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let _ = it.next();
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}
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Some(it.into_slice())
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}
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pub fn main() {
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// In a slice of zero-size elements the pointer is meaningless.
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// Ensure iteration still works even if the pointer is at the end of the address space.
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let slice: &[()] = unsafe { slice::from_raw_parts(-5isize as *const (), 10) };
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assert_eq!(slice.len(), 10);
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assert_eq!(slice.iter().count(), 10);
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// .nth() on the iterator should also behave correctly
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let mut it = slice.iter();
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assert!(it.nth(5).is_some());
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assert_eq!(it.count(), 4);
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// Converting Iter to a slice should never have a null pointer
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assert!(foo(slice).is_some());
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// Test mutable iterators as well
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let slice: &mut [()] = unsafe { slice::from_raw_parts_mut(-5isize as *mut (), 10) };
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assert_eq!(slice.len(), 10);
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assert_eq!(slice.iter_mut().count(), 10);
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{
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let mut it = slice.iter_mut();
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assert!(it.nth(5).is_some());
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assert_eq!(it.count(), 4);
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}
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assert!(foo_mut(slice).is_some())
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}
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