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
|
// Copyright 2014 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.
use std::default::Default;
use std::hash::Hash;
use std::{cast, mem, raw, ptr, slice};
use serialize::{Encodable, Decodable, Encoder, Decoder};
/// A non-growable owned slice. This would preferably become `~[T]`
/// under DST.
#[unsafe_no_drop_flag] // data is set to null on destruction
pub struct OwnedSlice<T> {
/// null iff len == 0
priv data: *mut T,
priv len: uint,
}
#[unsafe_destructor]
impl<T> Drop for OwnedSlice<T> {
fn drop(&mut self) {
if self.data.is_null() { return }
// extract the vector
let v = mem::replace(self, OwnedSlice::empty());
// free via the Vec destructor
v.into_vec();
}
}
impl<T> OwnedSlice<T> {
pub fn empty() -> OwnedSlice<T> {
OwnedSlice { data: ptr::mut_null(), len: 0 }
}
#[inline(never)]
pub fn from_vec(mut v: Vec<T>) -> OwnedSlice<T> {
let len = v.len();
if len == 0 {
OwnedSlice::empty()
} else {
let p = v.as_mut_ptr();
// we own the allocation now
unsafe {cast::forget(v)}
OwnedSlice { data: p, len: len }
}
}
#[inline(never)]
pub fn into_vec(self) -> Vec<T> {
// null is ok, because len == 0 in that case, as required by Vec.
unsafe {
let ret = Vec::from_raw_parts(self.len, self.len, self.data);
// the vector owns the allocation now
cast::forget(self);
ret
}
}
pub fn as_slice<'a>(&'a self) -> &'a [T] {
static PTR_MARKER: u8 = 0;
let ptr = if self.data.is_null() {
// length zero, i.e. this will never be read as a T.
&PTR_MARKER as *u8 as *T
} else {
self.data as *T
};
let slice: &[T] = unsafe {cast::transmute(raw::Slice {
data: ptr,
len: self.len
})};
slice
}
pub fn get<'a>(&'a self, i: uint) -> &'a T {
self.as_slice().get(i).expect("OwnedSlice: index out of bounds")
}
pub fn iter<'r>(&'r self) -> slice::Items<'r, T> {
self.as_slice().iter()
}
pub fn map<U>(&self, f: |&T| -> U) -> OwnedSlice<U> {
self.iter().map(f).collect()
}
}
impl<T> Default for OwnedSlice<T> {
fn default() -> OwnedSlice<T> {
OwnedSlice::empty()
}
}
impl<T: Clone> Clone for OwnedSlice<T> {
fn clone(&self) -> OwnedSlice<T> {
OwnedSlice::from_vec(Vec::from_slice(self.as_slice()))
}
}
impl<S: Writer, T: Hash<S>> Hash<S> for OwnedSlice<T> {
fn hash(&self, state: &mut S) {
self.as_slice().hash(state)
}
}
impl<T: Eq> Eq for OwnedSlice<T> {
fn eq(&self, other: &OwnedSlice<T>) -> bool {
self.as_slice() == other.as_slice()
}
}
impl<T: TotalEq> TotalEq for OwnedSlice<T> {}
impl<T> Container for OwnedSlice<T> {
fn len(&self) -> uint { self.len }
}
impl<T> FromIterator<T> for OwnedSlice<T> {
fn from_iter<I: Iterator<T>>(mut iter: I) -> OwnedSlice<T> {
OwnedSlice::from_vec(iter.collect())
}
}
impl<S: Encoder<E>, T: Encodable<S, E>, E> Encodable<S, E> for OwnedSlice<T> {
fn encode(&self, s: &mut S) -> Result<(), E> {
self.as_slice().encode(s)
}
}
impl<D: Decoder<E>, T: Decodable<D, E>, E> Decodable<D, E> for OwnedSlice<T> {
fn decode(d: &mut D) -> Result<OwnedSlice<T>, E> {
Ok(OwnedSlice::from_vec(match Decodable::decode(d) {
Ok(t) => t,
Err(e) => return Err(e)
}))
}
}
|
