/
ptr.rs
314 lines (270 loc) · 8.92 KB
/
ptr.rs
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
//! Unsafe pointer utility functions
#[forbid(deprecated_mode)];
#[forbid(deprecated_pattern)];
use cmp::{Eq, Ord};
use libc::{c_void, size_t};
#[nolink]
#[abi = "cdecl"]
extern mod libc_ {
#[rust_stack]
fn memcpy(dest: *mut c_void, src: *const c_void,
n: libc::size_t) -> *c_void;
#[rust_stack]
fn memmove(dest: *mut c_void, src: *const c_void,
n: libc::size_t) -> *c_void;
#[rust_stack]
fn memset(dest: *mut c_void, c: libc::c_int,
len: libc::size_t) -> *c_void;
}
#[abi = "rust-intrinsic"]
extern mod rusti {
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) } }
/// Get an unsafe mut pointer to a value
#[inline(always)]
pub pure fn mut_addr_of<T>(val: &T) -> *mut T {
unsafe {
cast::reinterpret_cast(&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.
pub pure fn is_null<T>(ptr: *const T) -> bool { ptr == null() }
/// Returns true if the pointer is not equal to the null pointer.
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 not overlap.
*/
#[inline(always)]
pub unsafe fn memcpy<T>(dst: *mut T, src: *const T, count: uint) {
let n = count * sys::size_of::<T>();
libc_::memcpy(dst as *mut c_void, src as *c_void, n as size_t);
}
/**
* Copies data from one location to another
*
* Copies `count` elements (not bytes) from `src` to `dst`. The source
* and destination may overlap.
*/
#[inline(always)]
pub unsafe fn memmove<T>(dst: *mut T, src: *const T, count: uint) {
let n = count * sys::size_of::<T>();
libc_::memmove(dst as *mut c_void, src as *c_void, n as size_t);
}
#[inline(always)]
pub unsafe fn memset<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 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 fn ref_eq<T>(thing: &a/T, other: &b/T) -> bool {
to_uint(thing) == to_uint(other)
}
pub trait Ptr<T> {
pure fn is_null() -> bool;
pure fn is_not_null() -> bool;
pure fn offset(count: uint) -> self;
}
/// Extension methods for pointers
impl<T> *T: Ptr<T> {
/// Returns true if the pointer is equal to the null pointer.
#[inline(always)]
pure fn is_null() -> bool { is_null(self) }
/// Returns true if the pointer is not equal to the null pointer.
#[inline(always)]
pure fn is_not_null() -> bool { is_not_null(self) }
/// Calculates the offset from a pointer.
#[inline(always)]
pure fn offset(count: uint) -> *T { offset(self, count) }
}
// Equality for pointers
impl<T> *const T : Eq {
pure fn eq(other: &*const T) -> bool unsafe {
let a: uint = cast::reinterpret_cast(&self);
let b: uint = cast::reinterpret_cast(&(*other));
return a == b;
}
pure fn ne(other: &*const T) -> bool { !self.eq(other) }
}
// Comparison for pointers
impl<T> *const T : Ord {
pure fn lt(other: &*const T) -> bool unsafe {
let a: uint = cast::reinterpret_cast(&self);
let b: uint = cast::reinterpret_cast(&(*other));
return a < b;
}
pure fn le(other: &*const T) -> bool unsafe {
let a: uint = cast::reinterpret_cast(&self);
let b: uint = cast::reinterpret_cast(&(*other));
return a <= b;
}
pure fn ge(other: &*const T) -> bool unsafe {
let a: uint = cast::reinterpret_cast(&self);
let b: uint = cast::reinterpret_cast(&(*other));
return a >= b;
}
pure fn gt(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
impl<T:Eq> &const T : Eq {
pure fn eq(other: & &const T) -> bool { return *self == *(*other); }
pure fn ne(other: & &const T) -> bool { return *self != *(*other); }
}
// Comparison for region pointers
impl<T:Ord> &const T : Ord {
pure fn lt(other: & &const T) -> bool { *self < *(*other) }
pure fn le(other: & &const T) -> bool { *self <= *(*other) }
pure fn ge(other: & &const T) -> bool { *self >= *(*other) }
pure fn gt(other: & &const T) -> bool { *self > *(*other) }
}
#[test]
pub fn test() {
unsafe {
type Pair = {mut fst: int, mut snd: int};
let p = {mut fst: 10, mut snd: 20};
let pptr: *mut Pair = mut_addr_of(&p);
let iptr: *mut int = cast::reinterpret_cast(&pptr);
assert (*iptr == 10);;
*iptr = 30;
assert (*iptr == 30);
assert (p.fst == 30);;
*pptr = {mut fst: 50, mut snd: 60};
assert (*iptr == 50);
assert (p.fst == 50);
assert (p.snd == 60);
let mut v0 = ~[32000u16, 32001u16, 32002u16];
let mut v1 = ~[0u16, 0u16, 0u16];
ptr::memcpy(ptr::mut_offset(vec::raw::to_mut_ptr(v1), 1u),
ptr::offset(vec::raw::to_ptr(v0), 1u), 1u);
assert (v1[0] == 0u16 && v1[1] == 32001u16 && v1[2] == 0u16);
ptr::memcpy(vec::raw::to_mut_ptr(v1),
ptr::offset(vec::raw::to_ptr(v0), 2u), 1u);
assert (v1[0] == 32002u16 && v1[1] == 32001u16 && v1[2] == 0u16);
ptr::memcpy(ptr::mut_offset(vec::raw::to_mut_ptr(v1), 2u),
vec::raw::to_ptr(v0), 1u);
assert (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 {
assert 2u == as_c_str(s, |p| position(p, |c| *c == 'l' as c_char));
assert 4u == as_c_str(s, |p| position(p, |c| *c == 'o' as c_char));
assert 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| {
assert unsafe { buf_len(vp) } == 3u;
assert len == 4u;
}
}
}
}
}
#[test]
pub fn test_is_null() {
let p: *int = ptr::null();
assert p.is_null();
assert !p.is_not_null();
let q = ptr::offset(p, 1u);
assert !q.is_null();
assert q.is_not_null();
}