307 lines
8.7 KiB
Rust
307 lines
8.7 KiB
Rust
//! Unsafe pointer utility functions
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use cmp::{Eq, Ord};
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use libc::{c_void, size_t};
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#[nolink]
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#[abi = "cdecl"]
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extern mod libc_ {
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#[legacy_exports];
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#[rust_stack]
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fn memcpy(dest: *mut c_void, src: *const c_void,
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n: libc::size_t) -> *c_void;
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#[rust_stack]
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fn memmove(dest: *mut c_void, src: *const c_void,
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n: libc::size_t) -> *c_void;
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#[rust_stack]
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fn memset(dest: *mut c_void, c: libc::c_int,
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len: libc::size_t) -> *c_void;
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}
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#[abi = "rust-intrinsic"]
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extern mod rusti {
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#[legacy_exports];
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fn addr_of<T>(val: T) -> *T;
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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 pure fn addr_of<T>(val: T) -> *T { unsafe { rusti::addr_of(val) } }
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/// Get an unsafe mut pointer to a value
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#[inline(always)]
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pub pure fn mut_addr_of<T>(val: T) -> *mut T {
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unsafe {
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cast::reinterpret_cast(&rusti::addr_of(val))
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}
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}
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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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unsafe {
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(ptr as uint + count * sys::size_of::<T>()) as *T
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}
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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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unsafe {
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(ptr as uint + count * sys::size_of::<T>()) as *T
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}
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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 = 0u;
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loop {
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if f(*offset(buf, i)) { return i; }
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else { i += 1u; }
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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 pure 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 pure 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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pub pure 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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pub pure 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 not overlap.
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*/
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#[inline(always)]
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pub unsafe fn memcpy<T>(dst: *mut T, src: *const T, count: uint) {
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let n = count * sys::size_of::<T>();
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libc_::memcpy(dst as *mut c_void, src as *c_void, n as size_t);
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}
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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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pub unsafe fn memmove<T>(dst: *mut T, src: *const T, count: uint) {
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let n = count * sys::size_of::<T>();
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libc_::memmove(dst as *mut c_void, src as *c_void, n as size_t);
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}
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#[inline(always)]
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pub unsafe fn memset<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 pure 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 pure 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 pure 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 unsafe {
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cast::reinterpret_cast(&thing)
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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<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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pub trait Ptr {
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pure fn is_null() -> bool;
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pure fn is_not_null() -> bool;
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}
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/// Extension methods for pointers
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impl<T> *T: Ptr {
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/// Returns true if the pointer is equal to the null pointer.
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pure fn is_null() -> bool { is_null(self) }
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/// Returns true if the pointer is not equal to the null pointer.
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pure fn is_not_null() -> bool { is_not_null(self) }
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}
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// Equality for pointers
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impl<T> *const T : Eq {
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pure fn eq(other: &*const T) -> bool 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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pure fn ne(other: &*const T) -> bool { !self.eq(other) }
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}
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// Comparison for pointers
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impl<T> *const T : Ord {
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pure fn lt(other: &*const T) -> bool 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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pure fn le(other: &*const T) -> bool 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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pure fn ge(other: &*const T) -> bool 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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pure fn gt(other: &*const T) -> bool 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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// Equality for region pointers
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impl<T:Eq> &const T : Eq {
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pure fn eq(other: & &const T) -> bool { return *self == *(*other); }
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pure fn ne(other: & &const T) -> bool { return *self != *(*other); }
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}
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// Comparison for region pointers
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impl<T:Ord> &const T : Ord {
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pure fn lt(other: & &const T) -> bool { *self < *(*other) }
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pure fn le(other: & &const T) -> bool { *self <= *(*other) }
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pure fn ge(other: & &const T) -> bool { *self >= *(*other) }
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pure fn gt(other: & &const T) -> bool { *self > *(*other) }
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}
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#[test]
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pub fn test() {
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unsafe {
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type Pair = {mut fst: int, mut snd: int};
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let p = {mut fst: 10, mut snd: 20};
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let pptr: *mut Pair = mut_addr_of(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 = {mut fst: 50, mut 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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ptr::memcpy(ptr::mut_offset(vec::raw::to_mut_ptr(v1), 1u),
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ptr::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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ptr::memcpy(vec::raw::to_mut_ptr(v1),
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ptr::offset(vec::raw::to_ptr(v0), 2u), 1u);
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assert (v1[0] == 32002u16 && v1[1] == 32001u16 && v1[2] == 0u16);
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ptr::memcpy(ptr::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 && v1[2] == 32000u16);
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}
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}
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#[test]
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pub 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, |c| c == 'l' as c_char));
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assert 4u == as_c_str(s, |p| position(p, |c| c == 'o' as c_char));
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assert 5u == as_c_str(s, |p| position(p, |c| c == 0 as c_char));
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}
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}
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#[test]
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pub 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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pub fn test_is_null() {
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let p: *int = ptr::null();
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assert p.is_null();
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assert !p.is_not_null();
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let q = ptr::offset(p, 1u);
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assert !q.is_null();
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assert q.is_not_null();
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}
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