/
ptr.rs
523 lines (471 loc) · 14.8 KB
/
ptr.rs
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// Copyright 2012-2013 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.
//! Unsafe pointer utility functions
use cast;
use libc;
use libc::{c_void, size_t};
use unstable::intrinsics::{memmove32,memmove64};
use sys;
#[cfg(test)] use vec;
#[cfg(test)] use str;
#[cfg(notest)] use cmp::{Eq, Ord};
use uint;
pub mod libc_ {
use libc::c_void;
use libc;
#[nolink]
#[abi = "cdecl"]
pub extern {
#[rust_stack]
unsafe fn memmove(dest: *mut c_void,
src: *const c_void,
n: libc::size_t)
-> *c_void;
#[rust_stack]
unsafe fn memset(dest: *mut c_void,
c: libc::c_int,
len: libc::size_t)
-> *c_void;
}
}
pub mod rusti {
#[abi = "rust-intrinsic"]
pub extern {
fn addr_of<T>(&&val: T) -> *T;
}
}
/// Get an unsafe pointer to a value
#[inline(always)]
pub pure fn addr_of<T>(val: &T) -> *T { unsafe { rusti::addr_of(*val) } }
/// Calculate the offset from a pointer
#[inline(always)]
pub pure fn offset<T>(ptr: *T, count: uint) -> *T {
unsafe {
(ptr as uint + count * sys::size_of::<T>()) as *T
}
}
/// Calculate the offset from a const pointer
#[inline(always)]
pub pure fn const_offset<T>(ptr: *const T, count: uint) -> *const T {
unsafe {
(ptr as uint + count * sys::size_of::<T>()) as *T
}
}
/// Calculate the offset from a mut pointer
#[inline(always)]
pub pure fn mut_offset<T>(ptr: *mut T, count: uint) -> *mut T {
(ptr as uint + count * sys::size_of::<T>()) as *mut T
}
/// Return the offset of the first null pointer in `buf`.
#[inline(always)]
pub unsafe fn buf_len<T>(buf: **T) -> uint {
position(buf, |i| *i == null())
}
/// Return the first offset `i` such that `f(buf[i]) == true`.
#[inline(always)]
pub unsafe fn position<T>(buf: *T, f: &fn(&T) -> bool) -> uint {
let mut i = 0;
loop {
if f(&(*offset(buf, i))) { return i; }
else { i += 1; }
}
}
/// Create an unsafe null pointer
#[inline(always)]
pub pure fn null<T>() -> *T { unsafe { cast::reinterpret_cast(&0u) } }
/// Create an unsafe mutable null pointer
#[inline(always)]
pub pure fn mut_null<T>() -> *mut T { unsafe { cast::reinterpret_cast(&0u) } }
/// Returns true if the pointer is equal to the null pointer.
#[inline(always)]
pub pure fn is_null<T>(ptr: *const T) -> bool { ptr == null() }
/// Returns true if the pointer is not equal to the null pointer.
#[inline(always)]
pub pure fn is_not_null<T>(ptr: *const T) -> bool { !is_null(ptr) }
/**
* Copies data from one location to another
*
* Copies `count` elements (not bytes) from `src` to `dst`. The source
* and destination may overlap.
*/
#[inline(always)]
#[cfg(target_word_size = "32")]
pub unsafe fn copy_memory<T>(dst: *mut T, src: *const T, count: uint) {
let n = count * sys::size_of::<T>();
memmove32(dst as *mut u8, src as *u8, n as u32);
}
#[inline(always)]
#[cfg(target_word_size = "64")]
pub unsafe fn copy_memory<T>(dst: *mut T, src: *const T, count: uint) {
let n = count * sys::size_of::<T>();
memmove64(dst as *mut u8, src as *u8, n as u64);
}
#[inline(always)]
pub unsafe fn set_memory<T>(dst: *mut T, c: int, count: uint) {
let n = count * sys::size_of::<T>();
libc_::memset(dst as *mut c_void, c as libc::c_int, n as size_t);
}
/**
Transform a region pointer - &T - to an unsafe pointer - *T.
This is safe, but is implemented with an unsafe block due to
reinterpret_cast.
*/
#[inline(always)]
pub pure fn to_unsafe_ptr<T>(thing: &T) -> *T {
unsafe { cast::reinterpret_cast(&thing) }
}
/**
Transform a const region pointer - &const T - to a const unsafe pointer -
*const T. This is safe, but is implemented with an unsafe block due to
reinterpret_cast.
*/
#[inline(always)]
pub pure fn to_const_unsafe_ptr<T>(thing: &const T) -> *const T {
unsafe { cast::reinterpret_cast(&thing) }
}
/**
Transform a mutable region pointer - &mut T - to a mutable unsafe pointer -
*mut T. This is safe, but is implemented with an unsafe block due to
reinterpret_cast.
*/
#[inline(always)]
pub pure fn to_mut_unsafe_ptr<T>(thing: &mut T) -> *mut T {
unsafe { cast::reinterpret_cast(&thing) }
}
/**
Cast a region pointer - &T - to a uint.
This is safe, but is implemented with an unsafe block due to
reinterpret_cast.
(I couldn't think of a cutesy name for this one.)
*/
#[inline(always)]
pub pure fn to_uint<T>(thing: &T) -> uint {
unsafe {
cast::reinterpret_cast(&thing)
}
}
/// Determine if two borrowed pointers point to the same thing.
#[inline(always)]
pub pure fn ref_eq<T>(thing: &'a T, other: &'b T) -> bool {
to_uint(thing) == to_uint(other)
}
/**
Given a **T (pointer to an array of pointers),
iterate through each *T, up to the provided `len`,
passing to the provided callback function
SAFETY NOTE: Pointer-arithmetic. Dragons be here.
*/
pub unsafe fn array_each_with_len<T>(arr: **T, len: uint, cb: &fn(*T)) {
debug!("array_each_with_len: before iterate");
if (arr as uint == 0) {
fail!(~"ptr::array_each_with_len failure: arr input is null pointer");
}
//let start_ptr = *arr;
uint::iterate(0, len, |e| {
let n = offset(arr, e);
cb(*n);
true
});
debug!("array_each_with_len: after iterate");
}
/**
Given a null-pointer-terminated **T (pointer to
an array of pointers), iterate through each *T,
passing to the provided callback function
SAFETY NOTE: This will only work with a null-terminated
pointer array. Barely less-dodgey Pointer Arithmetic.
Dragons be here.
*/
pub unsafe fn array_each<T>(arr: **T, cb: &fn(*T)) {
if (arr as uint == 0) {
fail!(~"ptr::array_each_with_len failure: arr input is null pointer");
}
let len = buf_len(arr);
debug!("array_each inferred len: %u",
len);
array_each_with_len(arr, len, cb);
}
pub trait Ptr<T> {
pure fn is_null(&self) -> bool;
pure fn is_not_null(&self) -> bool;
pure fn offset(&self, count: uint) -> Self;
}
/// Extension methods for immutable pointers
impl<T> Ptr<T> for *T {
/// Returns true if the pointer is equal to the null pointer.
#[inline(always)]
pure fn is_null(&self) -> bool { is_null(*self) }
/// Returns true if the pointer is not equal to the null pointer.
#[inline(always)]
pure fn is_not_null(&self) -> bool { is_not_null(*self) }
/// Calculates the offset from a pointer.
#[inline(always)]
pure fn offset(&self, count: uint) -> *T { offset(*self, count) }
}
/// Extension methods for mutable pointers
impl<T> Ptr<T> for *mut T {
/// Returns true if the pointer is equal to the null pointer.
#[inline(always)]
pure fn is_null(&self) -> bool { is_null(*self) }
/// Returns true if the pointer is not equal to the null pointer.
#[inline(always)]
pure fn is_not_null(&self) -> bool { is_not_null(*self) }
/// Calculates the offset from a mutable pointer.
#[inline(always)]
pure fn offset(&self, count: uint) -> *mut T { mut_offset(*self, count) }
}
// Equality for pointers
#[cfg(notest)]
impl<T> Eq for *const T {
#[inline(always)]
pure fn eq(&self, other: &*const T) -> bool {
unsafe {
let a: uint = cast::reinterpret_cast(&(*self));
let b: uint = cast::reinterpret_cast(&(*other));
return a == b;
}
}
#[inline(always)]
pure fn ne(&self, other: &*const T) -> bool { !(*self).eq(other) }
}
// Comparison for pointers
#[cfg(notest)]
impl<T> Ord for *const T {
#[inline(always)]
pure fn lt(&self, other: &*const T) -> bool {
unsafe {
let a: uint = cast::reinterpret_cast(&(*self));
let b: uint = cast::reinterpret_cast(&(*other));
return a < b;
}
}
#[inline(always)]
pure fn le(&self, other: &*const T) -> bool {
unsafe {
let a: uint = cast::reinterpret_cast(&(*self));
let b: uint = cast::reinterpret_cast(&(*other));
return a <= b;
}
}
#[inline(always)]
pure fn ge(&self, other: &*const T) -> bool {
unsafe {
let a: uint = cast::reinterpret_cast(&(*self));
let b: uint = cast::reinterpret_cast(&(*other));
return a >= b;
}
}
#[inline(always)]
pure fn gt(&self, other: &*const T) -> bool {
unsafe {
let a: uint = cast::reinterpret_cast(&(*self));
let b: uint = cast::reinterpret_cast(&(*other));
return a > b;
}
}
}
// Equality for region pointers
#[cfg(notest)]
impl<T:Eq> Eq for &'self const T {
#[inline(always)]
pure fn eq(&self, other: & &'self const T) -> bool {
return *(*self) == *(*other);
}
#[inline(always)]
pure fn ne(&self, other: & &'self const T) -> bool {
return *(*self) != *(*other);
}
}
// Comparison for region pointers
#[cfg(notest)]
impl<T:Ord> Ord for &'self const T {
#[inline(always)]
pure fn lt(&self, other: & &'self const T) -> bool {
*(*self) < *(*other)
}
#[inline(always)]
pure fn le(&self, other: & &'self const T) -> bool {
*(*self) <= *(*other)
}
#[inline(always)]
pure fn ge(&self, other: & &'self const T) -> bool {
*(*self) >= *(*other)
}
#[inline(always)]
pure fn gt(&self, other: & &'self const T) -> bool {
*(*self) > *(*other)
}
}
#[test]
pub fn test() {
unsafe {
struct Pair {mut fst: int, mut snd: int};
let mut p = Pair {fst: 10, snd: 20};
let pptr: *mut Pair = &mut p;
let iptr: *mut int = cast::reinterpret_cast(&pptr);
fail_unless!((*iptr == 10));;
*iptr = 30;
fail_unless!((*iptr == 30));
fail_unless!((p.fst == 30));;
*pptr = Pair {fst: 50, snd: 60};
fail_unless!((*iptr == 50));
fail_unless!((p.fst == 50));
fail_unless!((p.snd == 60));
let mut v0 = ~[32000u16, 32001u16, 32002u16];
let mut v1 = ~[0u16, 0u16, 0u16];
copy_memory(mut_offset(vec::raw::to_mut_ptr(v1), 1u),
offset(vec::raw::to_ptr(v0), 1u), 1u);
fail_unless!((v1[0] == 0u16 && v1[1] == 32001u16 && v1[2] == 0u16));
copy_memory(vec::raw::to_mut_ptr(v1),
offset(vec::raw::to_ptr(v0), 2u), 1u);
fail_unless!((v1[0] == 32002u16 && v1[1] == 32001u16 &&
v1[2] == 0u16));
copy_memory(mut_offset(vec::raw::to_mut_ptr(v1), 2u),
vec::raw::to_ptr(v0), 1u);
fail_unless!((v1[0] == 32002u16 && v1[1] == 32001u16 &&
v1[2] == 32000u16));
}
}
#[test]
pub fn test_position() {
use str::as_c_str;
use libc::c_char;
let s = ~"hello";
unsafe {
fail_unless!(2u == as_c_str(s, |p| position(p,
|c| *c == 'l' as c_char)));
fail_unless!(4u == as_c_str(s, |p| position(p,
|c| *c == 'o' as c_char)));
fail_unless!(5u == as_c_str(s, |p| position(p,
|c| *c == 0 as c_char)));
}
}
#[test]
pub fn test_buf_len() {
let s0 = ~"hello";
let s1 = ~"there";
let s2 = ~"thing";
do str::as_c_str(s0) |p0| {
do str::as_c_str(s1) |p1| {
do str::as_c_str(s2) |p2| {
let v = ~[p0, p1, p2, null()];
do vec::as_imm_buf(v) |vp, len| {
fail_unless!(unsafe { buf_len(vp) } == 3u);
fail_unless!(len == 4u);
}
}
}
}
}
#[test]
pub fn test_is_null() {
let p: *int = null();
fail_unless!(p.is_null());
fail_unless!(!p.is_not_null());
let q = offset(p, 1u);
fail_unless!(!q.is_null());
fail_unless!(q.is_not_null());
let mp: *mut int = mut_null();
fail_unless!(mp.is_null());
fail_unless!(!mp.is_not_null());
let mq = mp.offset(1u);
fail_unless!(!mq.is_null());
fail_unless!(mq.is_not_null());
}
#[cfg(test)]
pub mod ptr_tests {
use ptr;
use str;
use libc;
use vec;
#[test]
pub fn test_ptr_array_each_with_len() {
unsafe {
let one = ~"oneOne";
let two = ~"twoTwo";
let three = ~"threeThree";
let arr: ~[*i8] = ~[
::cast::transmute(&one[0]),
::cast::transmute(&two[0]),
::cast::transmute(&three[0]),
];
let expected_arr = [
one, two, three
];
let arr_ptr = &arr[0];
let mut ctr = 0;
let mut iteration_count = 0;
ptr::array_each_with_len(arr_ptr, vec::len(arr),
|e| {
let actual = str::raw::from_c_str(e);
let expected = copy expected_arr[ctr];
debug!(
"test_ptr_array_each e: %s, a: %s",
expected, actual);
fail_unless!(actual == expected);
ctr += 1;
iteration_count += 1;
});
fail_unless!(iteration_count == 3u);
}
}
#[test]
pub fn test_ptr_array_each() {
unsafe {
let one = ~"oneOne";
let two = ~"twoTwo";
let three = ~"threeThree";
let arr: ~[*i8] = ~[
::cast::transmute(&one[0]),
::cast::transmute(&two[0]),
::cast::transmute(&three[0]),
// fake a null terminator
0 as *i8
];
let expected_arr = [
one, two, three
];
let arr_ptr = &arr[0];
let mut ctr = 0;
let mut iteration_count = 0;
ptr::array_each(arr_ptr, |e| {
let actual = str::raw::from_c_str(e);
let expected = copy expected_arr[ctr];
debug!(
"test_ptr_array_each e: %s, a: %s",
expected, actual);
fail_unless!(actual == expected);
ctr += 1;
iteration_count += 1;
});
fail_unless!(iteration_count == 3);
}
}
#[test]
#[should_fail]
#[ignore(cfg(windows))]
pub fn test_ptr_array_each_with_len_null_ptr() {
unsafe {
ptr::array_each_with_len(0 as **libc::c_char, 1, |e| {
str::raw::from_c_str(e);
});
}
}
#[test]
#[should_fail]
#[ignore(cfg(windows))]
pub fn test_ptr_array_each_null_ptr() {
unsafe {
ptr::array_each(0 as **libc::c_char, |e| {
str::raw::from_c_str(e);
});
}
}
}