519 lines
15 KiB
Rust
519 lines
15 KiB
Rust
// Copyright 2012-2013 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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//! Unsafe pointer utility functions
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use cast;
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use libc;
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use libc::{c_void, size_t};
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use sys;
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#[cfg(notest)] use cmp::{Eq, Ord};
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use uint;
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pub mod libc_ {
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use libc::c_void;
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use libc;
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#[nolink]
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#[abi = "cdecl"]
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pub extern {
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#[rust_stack]
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unsafe fn memmove(dest: *mut c_void,
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src: *const c_void,
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n: libc::size_t)
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-> *c_void;
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#[rust_stack]
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unsafe fn memset(dest: *mut c_void,
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c: libc::c_int,
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len: libc::size_t)
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-> *c_void;
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}
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}
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pub mod rusti {
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#[abi = "rust-intrinsic"]
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pub extern "rust-intrinsic" {
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fn addr_of<T>(&&val: T) -> *T;
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}
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}
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/// Get an unsafe pointer to a value
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#[inline(always)]
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pub fn addr_of<T>(val: &T) -> *T { unsafe { rusti::addr_of(*val) } }
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/// Calculate the offset from a pointer
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#[inline(always)]
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pub fn offset<T>(ptr: *T, count: uint) -> *T {
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(ptr as uint + count * sys::size_of::<T>()) as *T
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}
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/// Calculate the offset from a const pointer
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#[inline(always)]
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pub fn const_offset<T>(ptr: *const T, count: uint) -> *const T {
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(ptr as uint + count * sys::size_of::<T>()) as *T
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}
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/// Calculate the offset from a mut pointer
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#[inline(always)]
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pub fn mut_offset<T>(ptr: *mut T, count: uint) -> *mut T {
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(ptr as uint + count * sys::size_of::<T>()) as *mut T
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}
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/// Return the offset of the first null pointer in `buf`.
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#[inline(always)]
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pub unsafe fn buf_len<T>(buf: **T) -> uint {
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position(buf, |i| *i == null())
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}
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/// Return the first offset `i` such that `f(buf[i]) == true`.
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#[inline(always)]
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pub unsafe fn position<T>(buf: *T, f: &fn(&T) -> bool) -> uint {
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let mut i = 0;
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loop {
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if f(&(*offset(buf, i))) { return i; }
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else { i += 1; }
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}
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}
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/// Create an unsafe null pointer
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#[inline(always)]
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pub fn null<T>() -> *T { unsafe { cast::reinterpret_cast(&0u) } }
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/// Create an unsafe mutable null pointer
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#[inline(always)]
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pub fn mut_null<T>() -> *mut T { unsafe { cast::reinterpret_cast(&0u) } }
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/// Returns true if the pointer is equal to the null pointer.
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#[inline(always)]
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pub fn is_null<T>(ptr: *const T) -> bool { ptr == null() }
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/// Returns true if the pointer is not equal to the null pointer.
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#[inline(always)]
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pub fn is_not_null<T>(ptr: *const T) -> bool { !is_null(ptr) }
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/**
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* Copies data from one location to another
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*
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* Copies `count` elements (not bytes) from `src` to `dst`. The source
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* and destination may overlap.
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*/
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#[inline(always)]
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#[cfg(target_word_size = "32")]
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pub unsafe fn copy_memory<T>(dst: *mut T, src: *const T, count: uint) {
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use unstable::intrinsics::memmove32;
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let n = count * sys::size_of::<T>();
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memmove32(dst as *mut u8, src as *u8, n as u32);
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}
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#[inline(always)]
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#[cfg(target_word_size = "64")]
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pub unsafe fn copy_memory<T>(dst: *mut T, src: *const T, count: uint) {
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use unstable::intrinsics::memmove64;
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let n = count * sys::size_of::<T>();
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memmove64(dst as *mut u8, src as *u8, n as u64);
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}
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#[inline(always)]
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pub unsafe fn set_memory<T>(dst: *mut T, c: int, count: uint) {
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let n = count * sys::size_of::<T>();
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libc_::memset(dst as *mut c_void, c as libc::c_int, n as size_t);
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}
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/**
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Transform a region pointer - &T - to an unsafe pointer - *T.
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This is safe, but is implemented with an unsafe block due to
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reinterpret_cast.
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*/
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#[inline(always)]
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pub fn to_unsafe_ptr<T>(thing: &T) -> *T {
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unsafe { cast::reinterpret_cast(&thing) }
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}
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/**
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Transform a const region pointer - &const T - to a const unsafe pointer -
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*const T. This is safe, but is implemented with an unsafe block due to
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reinterpret_cast.
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*/
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#[inline(always)]
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pub fn to_const_unsafe_ptr<T>(thing: &const T) -> *const T {
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unsafe { cast::reinterpret_cast(&thing) }
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}
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/**
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Transform a mutable region pointer - &mut T - to a mutable unsafe pointer -
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*mut T. This is safe, but is implemented with an unsafe block due to
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reinterpret_cast.
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*/
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#[inline(always)]
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pub fn to_mut_unsafe_ptr<T>(thing: &mut T) -> *mut T {
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unsafe { cast::reinterpret_cast(&thing) }
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}
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/**
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Cast a region pointer - &T - to a uint.
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This is safe, but is implemented with an unsafe block due to
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reinterpret_cast.
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(I couldn't think of a cutesy name for this one.)
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*/
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#[inline(always)]
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pub fn to_uint<T>(thing: &T) -> uint {
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unsafe {
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cast::reinterpret_cast(&thing)
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}
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}
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/// Determine if two borrowed pointers point to the same thing.
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#[inline(always)]
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pub fn ref_eq<'a,'b,T>(thing: &'a T, other: &'b T) -> bool {
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to_uint(thing) == to_uint(other)
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}
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/**
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Given a **T (pointer to an array of pointers),
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iterate through each *T, up to the provided `len`,
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passing to the provided callback function
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SAFETY NOTE: Pointer-arithmetic. Dragons be here.
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*/
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pub unsafe fn array_each_with_len<T>(arr: **T, len: uint, cb: &fn(*T)) {
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debug!("array_each_with_len: before iterate");
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if (arr as uint == 0) {
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fail!(~"ptr::array_each_with_len failure: arr input is null pointer");
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}
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//let start_ptr = *arr;
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uint::iterate(0, len, |e| {
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let n = offset(arr, e);
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cb(*n);
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true
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});
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debug!("array_each_with_len: after iterate");
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}
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/**
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Given a null-pointer-terminated **T (pointer to
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an array of pointers), iterate through each *T,
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passing to the provided callback function
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SAFETY NOTE: This will only work with a null-terminated
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pointer array. Barely less-dodgey Pointer Arithmetic.
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Dragons be here.
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*/
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pub unsafe fn array_each<T>(arr: **T, cb: &fn(*T)) {
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if (arr as uint == 0) {
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fail!(~"ptr::array_each_with_len failure: arr input is null pointer");
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}
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let len = buf_len(arr);
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debug!("array_each inferred len: %u",
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len);
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array_each_with_len(arr, len, cb);
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}
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pub trait Ptr<T> {
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fn is_null(&const self) -> bool;
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fn is_not_null(&const self) -> bool;
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fn offset(&self, count: uint) -> Self;
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}
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/// Extension methods for immutable pointers
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impl<T> Ptr<T> for *T {
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/// Returns true if the pointer is equal to the null pointer.
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#[inline(always)]
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fn is_null(&const self) -> bool { is_null(*self) }
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/// Returns true if the pointer is not equal to the null pointer.
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#[inline(always)]
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fn is_not_null(&const self) -> bool { is_not_null(*self) }
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/// Calculates the offset from a pointer.
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#[inline(always)]
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fn offset(&self, count: uint) -> *T { offset(*self, count) }
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}
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/// Extension methods for mutable pointers
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impl<T> Ptr<T> for *mut T {
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/// Returns true if the pointer is equal to the null pointer.
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#[inline(always)]
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fn is_null(&const self) -> bool { is_null(*self) }
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/// Returns true if the pointer is not equal to the null pointer.
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#[inline(always)]
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fn is_not_null(&const self) -> bool { is_not_null(*self) }
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/// Calculates the offset from a mutable pointer.
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#[inline(always)]
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fn offset(&self, count: uint) -> *mut T { mut_offset(*self, count) }
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}
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// Equality for pointers
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#[cfg(notest)]
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impl<T> Eq for *const T {
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#[inline(always)]
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fn eq(&self, other: &*const T) -> bool {
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unsafe {
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let a: uint = cast::reinterpret_cast(&(*self));
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let b: uint = cast::reinterpret_cast(&(*other));
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return a == b;
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}
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}
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#[inline(always)]
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fn ne(&self, other: &*const T) -> bool { !(*self).eq(other) }
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}
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// Comparison for pointers
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#[cfg(notest)]
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impl<T> Ord for *const T {
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#[inline(always)]
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fn lt(&self, other: &*const T) -> bool {
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unsafe {
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let a: uint = cast::reinterpret_cast(&(*self));
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let b: uint = cast::reinterpret_cast(&(*other));
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return a < b;
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}
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}
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#[inline(always)]
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fn le(&self, other: &*const T) -> bool {
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unsafe {
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let a: uint = cast::reinterpret_cast(&(*self));
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let b: uint = cast::reinterpret_cast(&(*other));
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return a <= b;
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}
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}
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#[inline(always)]
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fn ge(&self, other: &*const T) -> bool {
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unsafe {
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let a: uint = cast::reinterpret_cast(&(*self));
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let b: uint = cast::reinterpret_cast(&(*other));
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return a >= b;
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}
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}
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#[inline(always)]
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fn gt(&self, other: &*const T) -> bool {
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unsafe {
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let a: uint = cast::reinterpret_cast(&(*self));
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let b: uint = cast::reinterpret_cast(&(*other));
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return a > b;
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}
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}
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}
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// Equality for region pointers
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#[cfg(notest)]
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impl<'self,T:Eq> Eq for &'self const T {
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#[inline(always)]
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fn eq(&self, other: & &'self const T) -> bool {
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return *(*self) == *(*other);
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}
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#[inline(always)]
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fn ne(&self, other: & &'self const T) -> bool {
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return *(*self) != *(*other);
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}
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}
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// Comparison for region pointers
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#[cfg(notest)]
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impl<'self,T:Ord> Ord for &'self const T {
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#[inline(always)]
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fn lt(&self, other: & &'self const T) -> bool {
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*(*self) < *(*other)
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}
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#[inline(always)]
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fn le(&self, other: & &'self const T) -> bool {
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*(*self) <= *(*other)
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}
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#[inline(always)]
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fn ge(&self, other: & &'self const T) -> bool {
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*(*self) >= *(*other)
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}
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#[inline(always)]
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fn gt(&self, other: & &'self const T) -> bool {
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*(*self) > *(*other)
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}
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}
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#[cfg(test)]
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pub mod ptr_tests {
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use super::*;
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use prelude::*;
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#[test]
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fn test() {
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unsafe {
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struct Pair {mut fst: int, mut snd: int};
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let mut p = Pair {fst: 10, snd: 20};
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let pptr: *mut Pair = &mut p;
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let iptr: *mut int = cast::reinterpret_cast(&pptr);
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assert!((*iptr == 10));;
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*iptr = 30;
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assert!((*iptr == 30));
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assert!((p.fst == 30));;
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*pptr = Pair {fst: 50, snd: 60};
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assert!((*iptr == 50));
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assert!((p.fst == 50));
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assert!((p.snd == 60));
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let mut v0 = ~[32000u16, 32001u16, 32002u16];
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let mut v1 = ~[0u16, 0u16, 0u16];
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copy_memory(mut_offset(vec::raw::to_mut_ptr(v1), 1u),
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offset(vec::raw::to_ptr(v0), 1u), 1u);
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assert!((v1[0] == 0u16 && v1[1] == 32001u16 && v1[2] == 0u16));
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copy_memory(vec::raw::to_mut_ptr(v1),
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offset(vec::raw::to_ptr(v0), 2u), 1u);
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assert!((v1[0] == 32002u16 && v1[1] == 32001u16 &&
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v1[2] == 0u16));
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copy_memory(mut_offset(vec::raw::to_mut_ptr(v1), 2u),
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vec::raw::to_ptr(v0), 1u);
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assert!((v1[0] == 32002u16 && v1[1] == 32001u16 &&
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v1[2] == 32000u16));
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}
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}
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#[test]
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fn test_position() {
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use str::as_c_str;
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use libc::c_char;
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let s = ~"hello";
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unsafe {
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assert!(2u == as_c_str(s, |p| position(p,
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|c| *c == 'l' as c_char)));
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assert!(4u == as_c_str(s, |p| position(p,
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|c| *c == 'o' as c_char)));
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assert!(5u == as_c_str(s, |p| position(p,
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|c| *c == 0 as c_char)));
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}
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}
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#[test]
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fn test_buf_len() {
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let s0 = ~"hello";
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let s1 = ~"there";
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let s2 = ~"thing";
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do str::as_c_str(s0) |p0| {
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do str::as_c_str(s1) |p1| {
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do str::as_c_str(s2) |p2| {
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let v = ~[p0, p1, p2, null()];
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do vec::as_imm_buf(v) |vp, len| {
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assert!(unsafe { buf_len(vp) } == 3u);
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assert!(len == 4u);
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}
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}
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}
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}
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}
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#[test]
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fn test_is_null() {
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let p: *int = null();
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assert!(p.is_null());
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assert!(!p.is_not_null());
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let q = offset(p, 1u);
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assert!(!q.is_null());
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assert!(q.is_not_null());
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let mp: *mut int = mut_null();
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assert!(mp.is_null());
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assert!(!mp.is_not_null());
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let mq = mp.offset(1u);
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assert!(!mq.is_null());
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assert!(mq.is_not_null());
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}
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#[test]
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fn test_ptr_array_each_with_len() {
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unsafe {
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let one = ~"oneOne";
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let two = ~"twoTwo";
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let three = ~"threeThree";
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let arr: ~[*i8] = ~[
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::cast::transmute(&one[0]),
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::cast::transmute(&two[0]),
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::cast::transmute(&three[0]),
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];
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let expected_arr = [
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one, two, three
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];
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let arr_ptr = &arr[0];
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let mut ctr = 0;
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let mut iteration_count = 0;
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array_each_with_len(arr_ptr, vec::len(arr),
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|e| {
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let actual = str::raw::from_c_str(e);
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let expected = copy expected_arr[ctr];
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debug!(
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"test_ptr_array_each e: %s, a: %s",
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expected, actual);
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assert!(actual == expected);
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ctr += 1;
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iteration_count += 1;
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});
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assert!(iteration_count == 3u);
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}
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}
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#[test]
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fn test_ptr_array_each() {
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unsafe {
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let one = ~"oneOne";
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let two = ~"twoTwo";
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let three = ~"threeThree";
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let arr: ~[*i8] = ~[
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::cast::transmute(&one[0]),
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::cast::transmute(&two[0]),
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::cast::transmute(&three[0]),
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// fake a null terminator
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0 as *i8
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];
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let expected_arr = [
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one, two, three
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];
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let arr_ptr = &arr[0];
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let mut ctr = 0;
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let mut iteration_count = 0;
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array_each(arr_ptr, |e| {
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let actual = str::raw::from_c_str(e);
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let expected = copy expected_arr[ctr];
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debug!(
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"test_ptr_array_each e: %s, a: %s",
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expected, actual);
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assert!(actual == expected);
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ctr += 1;
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iteration_count += 1;
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});
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assert!(iteration_count == 3);
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}
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}
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#[test]
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#[should_fail]
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#[ignore(cfg(windows))]
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fn test_ptr_array_each_with_len_null_ptr() {
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unsafe {
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array_each_with_len(0 as **libc::c_char, 1, |e| {
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str::raw::from_c_str(e);
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});
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}
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}
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#[test]
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#[should_fail]
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#[ignore(cfg(windows))]
|
|
fn test_ptr_array_each_null_ptr() {
|
|
unsafe {
|
|
array_each(0 as **libc::c_char, |e| {
|
|
str::raw::from_c_str(e);
|
|
});
|
|
}
|
|
}
|
|
}
|