1 // Copyright 2014 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 //! An owned, growable vector.
15 use alloc::heap::{allocate, reallocate, deallocate};
18 use core::default::Default;
21 use core::num::{CheckedMul, CheckedAdd};
26 use {Collection, Mutable};
27 use slice::{MutableOrdVector, MutableVectorAllocating, CloneableVector};
28 use slice::{Items, MutItems};
30 /// An owned, growable vector.
35 /// # use std::vec::Vec;
36 /// let mut vec = Vec::new();
40 /// assert_eq!(vec.len(), 2);
41 /// assert_eq!(vec.get(0), &1);
43 /// assert_eq!(vec.pop(), Some(2));
44 /// assert_eq!(vec.len(), 1);
47 /// The `vec!` macro is provided to make initialization more convenient:
50 /// let mut vec = vec!(1i, 2i, 3i);
52 /// assert_eq!(vec, vec!(1, 2, 3, 4));
54 #[unsafe_no_drop_flag]
62 /// Constructs a new, empty `Vec`.
64 /// The vector will not allocate until elements are pushed onto it.
69 /// # use std::vec::Vec;
70 /// let mut vec: Vec<int> = Vec::new();
73 pub fn new() -> Vec<T> {
74 Vec { len: 0, cap: 0, ptr: 0 as *mut T }
77 /// Constructs a new, empty `Vec` with the specified capacity.
79 /// The vector will be able to hold exactly `capacity` elements without
80 /// reallocating. If `capacity` is 0, the vector will not allocate.
85 /// # use std::vec::Vec;
86 /// let vec: Vec<int> = Vec::with_capacity(10);
89 pub fn with_capacity(capacity: uint) -> Vec<T> {
90 if mem::size_of::<T>() == 0 {
91 Vec { len: 0, cap: uint::MAX, ptr: 0 as *mut T }
92 } else if capacity == 0 {
95 let size = capacity.checked_mul(&mem::size_of::<T>())
96 .expect("capacity overflow");
97 let ptr = unsafe { allocate(size, mem::min_align_of::<T>()) };
98 Vec { len: 0, cap: capacity, ptr: ptr as *mut T }
102 /// Creates and initializes a `Vec`.
104 /// Creates a `Vec` of size `length` and initializes the elements to the
105 /// value returned by the closure `op`.
110 /// # use std::vec::Vec;
111 /// let vec = Vec::from_fn(3, |idx| idx * 2);
112 /// assert_eq!(vec, vec!(0, 2, 4));
115 pub fn from_fn(length: uint, op: |uint| -> T) -> Vec<T> {
117 let mut xs = Vec::with_capacity(length);
118 while xs.len < length {
120 ptr::write(xs.as_mut_slice().unsafe_mut_ref(len), op(len));
127 /// Create a `Vec<T>` directly from the raw constituents.
129 /// This is highly unsafe:
131 /// - if `ptr` is null, then `length` and `capacity` should be 0
132 /// - `ptr` must point to an allocation of size `capacity`
133 /// - there must be `length` valid instances of type `T` at the
134 /// beginning of that allocation
135 /// - `ptr` must be allocated by the default `Vec` allocator
136 pub unsafe fn from_raw_parts(length: uint, capacity: uint,
137 ptr: *mut T) -> Vec<T> {
138 Vec { len: length, cap: capacity, ptr: ptr }
141 /// Consumes the `Vec`, partitioning it based on a predicate.
143 /// Partitions the `Vec` into two `Vec`s `(A,B)`, where all elements of `A`
144 /// satisfy `f` and all elements of `B` do not. The order of elements is
150 /// let vec = vec!(1i, 2i, 3i, 4i);
151 /// let (even, odd) = vec.partition(|&n| n % 2 == 0);
152 /// assert_eq!(even, vec!(2, 4));
153 /// assert_eq!(odd, vec!(1, 3));
156 pub fn partition(self, f: |&T| -> bool) -> (Vec<T>, Vec<T>) {
157 let mut lefts = Vec::new();
158 let mut rights = Vec::new();
160 for elt in self.move_iter() {
172 impl<T: Clone> Vec<T> {
173 /// Iterates over the `second` vector, copying each element and appending it to
174 /// the `first`. Afterwards, the `first` is then returned for use again.
179 /// let vec = vec!(1i, 2i);
180 /// let vec = vec.append([3i, 4i]);
181 /// assert_eq!(vec, vec!(1, 2, 3, 4));
184 pub fn append(mut self, second: &[T]) -> Vec<T> {
185 self.push_all(second);
189 /// Constructs a `Vec` by cloning elements of a slice.
194 /// # use std::vec::Vec;
195 /// let slice = [1i, 2, 3];
196 /// let vec = Vec::from_slice(slice);
199 pub fn from_slice(values: &[T]) -> Vec<T> {
200 values.iter().map(|x| x.clone()).collect()
203 /// Constructs a `Vec` with copies of a value.
205 /// Creates a `Vec` with `length` copies of `value`.
209 /// # use std::vec::Vec;
210 /// let vec = Vec::from_elem(3, "hi");
211 /// println!("{}", vec); // prints [hi, hi, hi]
214 pub fn from_elem(length: uint, value: T) -> Vec<T> {
216 let mut xs = Vec::with_capacity(length);
217 while xs.len < length {
219 ptr::write(xs.as_mut_slice().unsafe_mut_ref(len),
227 /// Appends all elements in a slice to the `Vec`.
229 /// Iterates over the slice `other`, clones each element, and then appends
230 /// it to this `Vec`. The `other` vector is traversed in-order.
235 /// let mut vec = vec!(1i);
236 /// vec.push_all([2i, 3, 4]);
237 /// assert_eq!(vec, vec!(1, 2, 3, 4));
240 pub fn push_all(&mut self, other: &[T]) {
241 self.extend(other.iter().map(|e| e.clone()));
244 /// Grows the `Vec` in-place.
246 /// Adds `n` copies of `value` to the `Vec`.
251 /// let mut vec = vec!("hello");
252 /// vec.grow(2, &("world"));
253 /// assert_eq!(vec, vec!("hello", "world", "world"));
255 pub fn grow(&mut self, n: uint, value: &T) {
256 let new_len = self.len() + n;
257 self.reserve(new_len);
258 let mut i: uint = 0u;
261 self.push((*value).clone());
266 /// Sets the value of a vector element at a given index, growing the vector
269 /// Sets the element at position `index` to `value`. If `index` is past the
270 /// end of the vector, expands the vector by replicating `initval` to fill
271 /// the intervening space.
276 /// let mut vec = vec!("a", "b", "c");
277 /// vec.grow_set(1, &("fill"), "d");
278 /// vec.grow_set(4, &("fill"), "e");
279 /// assert_eq!(vec, vec!("a", "d", "c", "fill", "e"));
281 pub fn grow_set(&mut self, index: uint, initval: &T, value: T) {
284 self.grow(index - l + 1u, initval);
286 *self.get_mut(index) = value;
289 /// Partitions a vector based on a predicate.
291 /// Clones the elements of the vector, partitioning them into two `Vec`s
292 /// `(A,B)`, where all elements of `A` satisfy `f` and all elements of `B`
293 /// do not. The order of elements is preserved.
298 /// let vec = vec!(1i, 2, 3, 4);
299 /// let (even, odd) = vec.partitioned(|&n| n % 2 == 0);
300 /// assert_eq!(even, vec!(2i, 4));
301 /// assert_eq!(odd, vec!(1i, 3));
303 pub fn partitioned(&self, f: |&T| -> bool) -> (Vec<T>, Vec<T>) {
304 let mut lefts = Vec::new();
305 let mut rights = Vec::new();
307 for elt in self.iter() {
309 lefts.push(elt.clone());
311 rights.push(elt.clone());
320 impl<T:Clone> Clone for Vec<T> {
321 fn clone(&self) -> Vec<T> {
323 let mut vector = Vec::with_capacity(len);
324 // Unsafe code so this can be optimised to a memcpy (or something
325 // similarly fast) when T is Copy. LLVM is easily confused, so any
326 // extra operations during the loop can prevent this optimisation
328 let this_slice = self.as_slice();
329 while vector.len < len {
331 let len = vector.len;
333 vector.as_mut_slice().unsafe_mut_ref(len),
334 this_slice.unsafe_ref(len).clone());
342 fn clone_from(&mut self, other: &Vec<T>) {
343 // drop anything in self that will not be overwritten
344 if self.len() > other.len() {
345 self.truncate(other.len())
348 // reuse the contained values' allocations/resources.
349 for (place, thing) in self.mut_iter().zip(other.iter()) {
350 place.clone_from(thing)
353 // self.len <= other.len due to the truncate above, so the
354 // slice here is always in-bounds.
355 let len = self.len();
356 self.extend(other.slice_from(len).iter().map(|x| x.clone()));
360 impl<T> FromIterator<T> for Vec<T> {
362 fn from_iter<I:Iterator<T>>(mut iterator: I) -> Vec<T> {
363 let (lower, _) = iterator.size_hint();
364 let mut vector = Vec::with_capacity(lower);
365 for element in iterator {
372 impl<T> Extendable<T> for Vec<T> {
374 fn extend<I: Iterator<T>>(&mut self, mut iterator: I) {
375 let (lower, _) = iterator.size_hint();
376 self.reserve_additional(lower);
377 for element in iterator {
383 impl<T: PartialEq> PartialEq for Vec<T> {
385 fn eq(&self, other: &Vec<T>) -> bool {
386 self.as_slice() == other.as_slice()
390 impl<T: PartialOrd> PartialOrd for Vec<T> {
392 fn partial_cmp(&self, other: &Vec<T>) -> Option<Ordering> {
393 self.as_slice().partial_cmp(&other.as_slice())
397 impl<T: Eq> Eq for Vec<T> {}
399 impl<T: PartialEq, V: Vector<T>> Equiv<V> for Vec<T> {
401 fn equiv(&self, other: &V) -> bool { self.as_slice() == other.as_slice() }
404 impl<T: Ord> Ord for Vec<T> {
406 fn cmp(&self, other: &Vec<T>) -> Ordering {
407 self.as_slice().cmp(&other.as_slice())
411 impl<T> Collection for Vec<T> {
413 fn len(&self) -> uint {
418 impl<T: Clone> CloneableVector<T> for Vec<T> {
419 fn to_owned(&self) -> Vec<T> { self.clone() }
420 fn into_owned(self) -> Vec<T> { self }
423 // FIXME: #13996: need a way to mark the return value as `noalias`
425 unsafe fn alloc_or_realloc<T>(ptr: *mut T, size: uint, old_size: uint) -> *mut T {
427 allocate(size, mem::min_align_of::<T>()) as *mut T
429 reallocate(ptr as *mut u8, size,
430 mem::min_align_of::<T>(), old_size) as *mut T
435 unsafe fn dealloc<T>(ptr: *mut T, len: uint) {
436 if mem::size_of::<T>() != 0 {
437 deallocate(ptr as *mut u8,
438 len * mem::size_of::<T>(),
439 mem::min_align_of::<T>())
444 /// Returns the number of elements the vector can hold without
450 /// # use std::vec::Vec;
451 /// let vec: Vec<int> = Vec::with_capacity(10);
452 /// assert_eq!(vec.capacity(), 10);
455 pub fn capacity(&self) -> uint {
459 /// Reserves capacity for at least `n` additional elements in the given
464 /// Fails if the new capacity overflows `uint`.
469 /// # use std::vec::Vec;
470 /// let mut vec: Vec<int> = vec!(1i);
471 /// vec.reserve_additional(10);
472 /// assert!(vec.capacity() >= 11);
474 pub fn reserve_additional(&mut self, extra: uint) {
475 if self.cap - self.len < extra {
476 match self.len.checked_add(&extra) {
477 None => fail!("Vec::reserve_additional: `uint` overflow"),
478 Some(new_cap) => self.reserve(new_cap)
483 /// Reserves capacity for at least `n` elements in the given vector.
485 /// This function will over-allocate in order to amortize the allocation
486 /// costs in scenarios where the caller may need to repeatedly reserve
487 /// additional space.
489 /// If the capacity for `self` is already equal to or greater than the
490 /// requested capacity, then no action is taken.
495 /// let mut vec = vec!(1i, 2, 3);
497 /// assert!(vec.capacity() >= 10);
499 pub fn reserve(&mut self, capacity: uint) {
500 if capacity >= self.len {
501 self.reserve_exact(num::next_power_of_two(capacity))
505 /// Reserves capacity for exactly `capacity` elements in the given vector.
507 /// If the capacity for `self` is already equal to or greater than the
508 /// requested capacity, then no action is taken.
513 /// # use std::vec::Vec;
514 /// let mut vec: Vec<int> = Vec::with_capacity(10);
515 /// vec.reserve_exact(11);
516 /// assert_eq!(vec.capacity(), 11);
518 pub fn reserve_exact(&mut self, capacity: uint) {
519 if mem::size_of::<T>() == 0 { return }
521 if capacity > self.cap {
522 let size = capacity.checked_mul(&mem::size_of::<T>())
523 .expect("capacity overflow");
525 self.ptr = alloc_or_realloc(self.ptr, size,
526 self.cap * mem::size_of::<T>());
532 /// Shrink the capacity of the vector as much as possible
537 /// let mut vec = vec!(1i, 2, 3);
538 /// vec.shrink_to_fit();
540 pub fn shrink_to_fit(&mut self) {
541 if mem::size_of::<T>() == 0 { return }
546 dealloc(self.ptr, self.cap)
552 // Overflow check is unnecessary as the vector is already at
554 self.ptr = reallocate(self.ptr as *mut u8,
555 self.len * mem::size_of::<T>(),
556 mem::min_align_of::<T>(),
557 self.cap * mem::size_of::<T>()) as *mut T;
563 /// Remove the last element from a vector and return it, or `None` if it is
569 /// let mut vec = vec!(1i, 2, 3);
570 /// assert_eq!(vec.pop(), Some(3));
571 /// assert_eq!(vec, vec!(1, 2));
574 pub fn pop(&mut self) -> Option<T> {
580 Some(ptr::read(self.as_slice().unsafe_ref(self.len())))
585 /// Append an element to a vector.
589 /// Fails if the number of elements in the vector overflows a `uint`.
594 /// let mut vec = vec!(1i, 2);
596 /// assert_eq!(vec, vec!(1, 2, 3));
599 pub fn push(&mut self, value: T) {
600 if mem::size_of::<T>() == 0 {
601 // zero-size types consume no memory, so we can't rely on the address space running out
602 self.len = self.len.checked_add(&1).expect("length overflow");
603 unsafe { mem::forget(value); }
606 if self.len == self.cap {
607 let old_size = self.cap * mem::size_of::<T>();
608 let size = max(old_size, 2 * mem::size_of::<T>()) * 2;
609 if old_size > size { fail!("capacity overflow") }
611 self.ptr = alloc_or_realloc(self.ptr, size,
612 self.cap * mem::size_of::<T>());
614 self.cap = max(self.cap, 2) * 2;
618 let end = (self.ptr as *const T).offset(self.len as int) as *mut T;
619 ptr::write(&mut *end, value);
624 /// Appends one element to the vector provided. The vector itself is then
625 /// returned for use again.
630 /// let vec = vec!(1i, 2);
631 /// let vec = vec.append_one(3);
632 /// assert_eq!(vec, vec!(1, 2, 3));
635 pub fn append_one(mut self, x: T) -> Vec<T> {
640 /// Shorten a vector, dropping excess elements.
642 /// If `len` is greater than the vector's current length, this has no
648 /// let mut vec = vec!(1i, 2, 3, 4);
650 /// assert_eq!(vec, vec!(1, 2));
652 pub fn truncate(&mut self, len: uint) {
654 // drop any extra elements
655 while len < self.len {
656 // decrement len before the read(), so a failure on Drop doesn't
657 // re-drop the just-failed value.
659 ptr::read(self.as_slice().unsafe_ref(self.len));
664 /// Work with `self` as a mutable slice.
669 /// fn foo(slice: &mut [int]) {}
671 /// let mut vec = vec!(1i, 2);
672 /// foo(vec.as_mut_slice());
675 pub fn as_mut_slice<'a>(&'a mut self) -> &'a mut [T] {
677 mem::transmute(Slice {
678 data: self.as_mut_ptr() as *const T,
684 /// Creates a consuming iterator, that is, one that moves each
685 /// value out of the vector (from start to end). The vector cannot
686 /// be used after calling this.
691 /// let v = vec!("a".to_string(), "b".to_string());
692 /// for s in v.move_iter() {
693 /// // s has type String, not &String
694 /// println!("{}", s);
698 pub fn move_iter(self) -> MoveItems<T> {
700 let iter = mem::transmute(self.as_slice().iter());
704 MoveItems { allocation: ptr, cap: cap, iter: iter }
709 /// Sets the length of a vector.
711 /// This will explicitly set the size of the vector, without actually
712 /// modifying its buffers, so it is up to the caller to ensure that the
713 /// vector is actually the specified size.
715 pub unsafe fn set_len(&mut self, len: uint) {
719 /// Returns a reference to the value at index `index`.
723 /// Fails if `index` is out of bounds
728 /// let vec = vec!(1i, 2, 3);
729 /// assert!(vec.get(1) == &2);
732 pub fn get<'a>(&'a self, index: uint) -> &'a T {
733 &self.as_slice()[index]
736 /// Returns a mutable reference to the value at index `index`.
740 /// Fails if `index` is out of bounds
745 /// let mut vec = vec!(1i, 2, 3);
746 /// *vec.get_mut(1) = 4;
747 /// assert_eq!(vec, vec!(1i, 4, 3));
750 pub fn get_mut<'a>(&'a mut self, index: uint) -> &'a mut T {
751 &mut self.as_mut_slice()[index]
754 /// Returns an iterator over references to the elements of the vector in
760 /// let vec = vec!(1i, 2, 3);
761 /// for num in vec.iter() {
762 /// println!("{}", *num);
766 pub fn iter<'a>(&'a self) -> Items<'a,T> {
767 self.as_slice().iter()
771 /// Returns an iterator over mutable references to the elements of the
777 /// let mut vec = vec!(1i, 2, 3);
778 /// for num in vec.mut_iter() {
783 pub fn mut_iter<'a>(&'a mut self) -> MutItems<'a,T> {
784 self.as_mut_slice().mut_iter()
787 /// Sort the vector, in place, using `compare` to compare elements.
789 /// This sort is `O(n log n)` worst-case and stable, but allocates
790 /// approximately `2 * n`, where `n` is the length of `self`.
795 /// let mut v = vec!(5i, 4, 1, 3, 2);
796 /// v.sort_by(|a, b| a.cmp(b));
797 /// assert_eq!(v, vec!(1i, 2, 3, 4, 5));
799 /// // reverse sorting
800 /// v.sort_by(|a, b| b.cmp(a));
801 /// assert_eq!(v, vec!(5i, 4, 3, 2, 1));
804 pub fn sort_by(&mut self, compare: |&T, &T| -> Ordering) {
805 self.as_mut_slice().sort_by(compare)
808 /// Returns a slice of self spanning the interval [`start`, `end`).
812 /// Fails when the slice (or part of it) is outside the bounds of self, or when
818 /// let vec = vec!(1i, 2, 3, 4);
819 /// assert!(vec.slice(0, 2) == [1, 2]);
822 pub fn slice<'a>(&'a self, start: uint, end: uint) -> &'a [T] {
823 self.as_slice().slice(start, end)
826 /// Returns a slice containing all but the first element of the vector.
830 /// Fails when the vector is empty.
835 /// let vec = vec!(1i, 2, 3);
836 /// assert!(vec.tail() == [2, 3]);
839 pub fn tail<'a>(&'a self) -> &'a [T] {
840 self.as_slice().tail()
843 /// Returns all but the first `n' elements of a vector.
847 /// Fails when there are fewer than `n` elements in the vector.
852 /// let vec = vec!(1i, 2, 3, 4);
853 /// assert!(vec.tailn(2) == [3, 4]);
856 pub fn tailn<'a>(&'a self, n: uint) -> &'a [T] {
857 self.as_slice().tailn(n)
860 /// Returns a reference to the last element of a vector, or `None` if it is
866 /// let vec = vec!(1i, 2, 3);
867 /// assert!(vec.last() == Some(&3));
870 pub fn last<'a>(&'a self) -> Option<&'a T> {
871 self.as_slice().last()
874 /// Returns a mutable reference to the last element of a vector, or `None`
880 /// let mut vec = vec!(1i, 2, 3);
881 /// *vec.mut_last().unwrap() = 4;
882 /// assert_eq!(vec, vec!(1i, 2, 4));
885 pub fn mut_last<'a>(&'a mut self) -> Option<&'a mut T> {
886 self.as_mut_slice().mut_last()
889 /// Remove an element from anywhere in the vector and return it, replacing
890 /// it with the last element. This does not preserve ordering, but is O(1).
892 /// Returns `None` if `index` is out of bounds.
896 /// let mut v = vec!("foo".to_string(), "bar".to_string(),
897 /// "baz".to_string(), "qux".to_string());
899 /// assert_eq!(v.swap_remove(1), Some("bar".to_string()));
900 /// assert_eq!(v, vec!("foo".to_string(), "qux".to_string(), "baz".to_string()));
902 /// assert_eq!(v.swap_remove(0), Some("foo".to_string()));
903 /// assert_eq!(v, vec!("baz".to_string(), "qux".to_string()));
905 /// assert_eq!(v.swap_remove(2), None);
908 pub fn swap_remove(&mut self, index: uint) -> Option<T> {
909 let length = self.len();
910 if index < length - 1 {
911 self.as_mut_slice().swap(index, length - 1);
912 } else if index >= length {
918 /// Prepend an element to the vector.
922 /// This is an O(n) operation as it requires copying every element in the
928 /// let mut vec = vec!(1i, 2, 3);
930 /// assert_eq!(vec, vec!(4, 1, 2, 3));
933 pub fn unshift(&mut self, element: T) {
934 self.insert(0, element)
937 /// Removes the first element from a vector and returns it, or `None` if
938 /// the vector is empty.
942 /// This is an O(n) operation as it requires copying every element in the
948 /// let mut vec = vec!(1i, 2, 3);
949 /// assert!(vec.shift() == Some(1));
950 /// assert_eq!(vec, vec!(2, 3));
953 pub fn shift(&mut self) -> Option<T> {
957 /// Insert an element at position `index` within the vector, shifting all
958 /// elements after position i one position to the right.
962 /// Fails if `index` is not between `0` and the vector's length (both
963 /// bounds inclusive).
968 /// let mut vec = vec!(1i, 2, 3);
969 /// vec.insert(1, 4);
970 /// assert_eq!(vec, vec!(1, 4, 2, 3));
971 /// vec.insert(4, 5);
972 /// assert_eq!(vec, vec!(1, 4, 2, 3, 5));
974 pub fn insert(&mut self, index: uint, element: T) {
975 let len = self.len();
976 assert!(index <= len);
977 // space for the new element
978 self.reserve(len + 1);
980 unsafe { // infallible
981 // The spot to put the new value
983 let p = self.as_mut_ptr().offset(index as int);
984 // Shift everything over to make space. (Duplicating the
985 // `index`th element into two consecutive places.)
986 ptr::copy_memory(p.offset(1), &*p, len - index);
987 // Write it in, overwriting the first copy of the `index`th
989 ptr::write(&mut *p, element);
991 self.set_len(len + 1);
995 /// Remove and return the element at position `index` within the vector,
996 /// shifting all elements after position `index` one position to the left.
997 /// Returns `None` if `i` is out of bounds.
1002 /// let mut v = vec!(1i, 2, 3);
1003 /// assert_eq!(v.remove(1), Some(2));
1004 /// assert_eq!(v, vec!(1, 3));
1006 /// assert_eq!(v.remove(4), None);
1007 /// // v is unchanged:
1008 /// assert_eq!(v, vec!(1, 3));
1010 pub fn remove(&mut self, index: uint) -> Option<T> {
1011 let len = self.len();
1013 unsafe { // infallible
1016 // the place we are taking from.
1017 let ptr = self.as_mut_ptr().offset(index as int);
1018 // copy it out, unsafely having a copy of the value on
1019 // the stack and in the vector at the same time.
1020 ret = Some(ptr::read(ptr as *const T));
1022 // Shift everything down to fill in that spot.
1023 ptr::copy_memory(ptr, &*ptr.offset(1), len - index - 1);
1025 self.set_len(len - 1);
1033 /// Takes ownership of the vector `other`, moving all elements into
1034 /// the current vector. This does not copy any elements, and it is
1035 /// illegal to use the `other` vector after calling this method
1036 /// (because it is moved here).
1041 /// let mut vec = vec!(box 1i);
1042 /// vec.push_all_move(vec!(box 2, box 3, box 4));
1043 /// assert_eq!(vec, vec!(box 1, box 2, box 3, box 4));
1046 pub fn push_all_move(&mut self, other: Vec<T>) {
1047 self.extend(other.move_iter());
1050 /// Returns a mutable slice of `self` between `start` and `end`.
1054 /// Fails when `start` or `end` point outside the bounds of `self`, or when
1055 /// `start` > `end`.
1060 /// let mut vec = vec!(1i, 2, 3, 4);
1061 /// assert!(vec.mut_slice(0, 2) == [1, 2]);
1064 pub fn mut_slice<'a>(&'a mut self, start: uint, end: uint)
1066 self.as_mut_slice().mut_slice(start, end)
1069 /// Returns a mutable slice of self from `start` to the end of the vec.
1073 /// Fails when `start` points outside the bounds of self.
1078 /// let mut vec = vec!(1i, 2, 3, 4);
1079 /// assert!(vec.mut_slice_from(2) == [3, 4]);
1082 pub fn mut_slice_from<'a>(&'a mut self, start: uint) -> &'a mut [T] {
1083 self.as_mut_slice().mut_slice_from(start)
1086 /// Returns a mutable slice of self from the start of the vec to `end`.
1090 /// Fails when `end` points outside the bounds of self.
1095 /// let mut vec = vec!(1i, 2, 3, 4);
1096 /// assert!(vec.mut_slice_to(2) == [1, 2]);
1099 pub fn mut_slice_to<'a>(&'a mut self, end: uint) -> &'a mut [T] {
1100 self.as_mut_slice().mut_slice_to(end)
1103 /// Returns a pair of mutable slices that divides the vec at an index.
1105 /// The first will contain all indices from `[0, mid)` (excluding
1106 /// the index `mid` itself) and the second will contain all
1107 /// indices from `[mid, len)` (excluding the index `len` itself).
1111 /// Fails if `mid > len`.
1116 /// let mut vec = vec!(1i, 2, 3, 4, 5, 6);
1118 /// // scoped to restrict the lifetime of the borrows
1120 /// let (left, right) = vec.mut_split_at(0);
1121 /// assert!(left == &mut []);
1122 /// assert!(right == &mut [1, 2, 3, 4, 5, 6]);
1126 /// let (left, right) = vec.mut_split_at(2);
1127 /// assert!(left == &mut [1, 2]);
1128 /// assert!(right == &mut [3, 4, 5, 6]);
1132 /// let (left, right) = vec.mut_split_at(6);
1133 /// assert!(left == &mut [1, 2, 3, 4, 5, 6]);
1134 /// assert!(right == &mut []);
1138 pub fn mut_split_at<'a>(&'a mut self, mid: uint) -> (&'a mut [T], &'a mut [T]) {
1139 self.as_mut_slice().mut_split_at(mid)
1142 /// Reverse the order of elements in a vector, in place.
1147 /// let mut v = vec!(1i, 2, 3);
1149 /// assert_eq!(v, vec!(3i, 2, 1));
1152 pub fn reverse(&mut self) {
1153 self.as_mut_slice().reverse()
1156 /// Returns a slice of `self` from `start` to the end of the vec.
1160 /// Fails when `start` points outside the bounds of self.
1165 /// let vec = vec!(1i, 2, 3);
1166 /// assert!(vec.slice_from(1) == [2, 3]);
1169 pub fn slice_from<'a>(&'a self, start: uint) -> &'a [T] {
1170 self.as_slice().slice_from(start)
1173 /// Returns a slice of self from the start of the vec to `end`.
1177 /// Fails when `end` points outside the bounds of self.
1182 /// let vec = vec!(1i, 2, 3);
1183 /// assert!(vec.slice_to(2) == [1, 2]);
1186 pub fn slice_to<'a>(&'a self, end: uint) -> &'a [T] {
1187 self.as_slice().slice_to(end)
1190 /// Returns a slice containing all but the last element of the vector.
1194 /// Fails if the vector is empty
1196 pub fn init<'a>(&'a self) -> &'a [T] {
1197 self.slice(0, self.len() - 1)
1201 /// Returns an unsafe pointer to the vector's buffer.
1203 /// The caller must ensure that the vector outlives the pointer this
1204 /// function returns, or else it will end up pointing to garbage.
1206 /// Modifying the vector may cause its buffer to be reallocated, which
1207 /// would also make any pointers to it invalid.
1209 pub fn as_ptr(&self) -> *const T {
1210 // If we have a 0-sized vector, then the base pointer should not be NULL
1211 // because an iterator over the slice will attempt to yield the base
1212 // pointer as the first element in the vector, but this will end up
1213 // being Some(NULL) which is optimized to None.
1214 if mem::size_of::<T>() == 0 {
1217 self.ptr as *const T
1221 /// Returns a mutable unsafe pointer to the vector's buffer.
1223 /// The caller must ensure that the vector outlives the pointer this
1224 /// function returns, or else it will end up pointing to garbage.
1226 /// Modifying the vector may cause its buffer to be reallocated, which
1227 /// would also make any pointers to it invalid.
1229 pub fn as_mut_ptr(&mut self) -> *mut T {
1230 // see above for the 0-size check
1231 if mem::size_of::<T>() == 0 {
1238 /// Retains only the elements specified by the predicate.
1240 /// In other words, remove all elements `e` such that `f(&e)` returns false.
1241 /// This method operates in place and preserves the order the retained elements.
1246 /// let mut vec = vec!(1i, 2, 3, 4);
1247 /// vec.retain(|x| x%2 == 0);
1248 /// assert_eq!(vec, vec!(2, 4));
1250 pub fn retain(&mut self, f: |&T| -> bool) {
1251 let len = self.len();
1254 let v = self.as_mut_slice();
1256 for i in range(0u, len) {
1265 self.truncate(len - del);
1269 /// Expands a vector in place, initializing the new elements to the result of a function.
1271 /// The vector is grown by `n` elements. The i-th new element are initialized to the value
1272 /// returned by `f(i)` where `i` is in the range [0, n).
1277 /// let mut vec = vec!(0u, 1);
1278 /// vec.grow_fn(3, |i| i);
1279 /// assert_eq!(vec, vec!(0, 1, 0, 1, 2));
1281 pub fn grow_fn(&mut self, n: uint, f: |uint| -> T) {
1282 self.reserve_additional(n);
1283 for i in range(0u, n) {
1289 impl<T:Ord> Vec<T> {
1290 /// Sorts the vector in place.
1292 /// This sort is `O(n log n)` worst-case and stable, but allocates
1293 /// approximately `2 * n`, where `n` is the length of `self`.
1298 /// let mut vec = vec!(3i, 1, 2);
1300 /// assert_eq!(vec, vec!(1, 2, 3));
1302 pub fn sort(&mut self) {
1303 self.as_mut_slice().sort()
1307 impl<T> Mutable for Vec<T> {
1309 fn clear(&mut self) {
1314 impl<T:PartialEq> Vec<T> {
1315 /// Return true if a vector contains an element with the given value
1320 /// let vec = vec!(1i, 2, 3);
1321 /// assert!(vec.contains(&1));
1324 pub fn contains(&self, x: &T) -> bool {
1325 self.as_slice().contains(x)
1328 /// Remove consecutive repeated elements in the vector.
1330 /// If the vector is sorted, this removes all duplicates.
1335 /// let mut vec = vec!(1i, 2, 2, 3, 2);
1337 /// assert_eq!(vec, vec!(1i, 2, 3, 2));
1339 pub fn dedup(&mut self) {
1341 // Although we have a mutable reference to `self`, we cannot make
1342 // *arbitrary* changes. The `PartialEq` comparisons could fail, so we
1343 // must ensure that the vector is in a valid state at all time.
1345 // The way that we handle this is by using swaps; we iterate
1346 // over all the elements, swapping as we go so that at the end
1347 // the elements we wish to keep are in the front, and those we
1348 // wish to reject are at the back. We can then truncate the
1349 // vector. This operation is still O(n).
1351 // Example: We start in this state, where `r` represents "next
1352 // read" and `w` represents "next_write`.
1355 // +---+---+---+---+---+---+
1356 // | 0 | 1 | 1 | 2 | 3 | 3 |
1357 // +---+---+---+---+---+---+
1360 // Comparing self[r] against self[w-1], this is not a duplicate, so
1361 // we swap self[r] and self[w] (no effect as r==w) and then increment both
1362 // r and w, leaving us with:
1365 // +---+---+---+---+---+---+
1366 // | 0 | 1 | 1 | 2 | 3 | 3 |
1367 // +---+---+---+---+---+---+
1370 // Comparing self[r] against self[w-1], this value is a duplicate,
1371 // so we increment `r` but leave everything else unchanged:
1374 // +---+---+---+---+---+---+
1375 // | 0 | 1 | 1 | 2 | 3 | 3 |
1376 // +---+---+---+---+---+---+
1379 // Comparing self[r] against self[w-1], this is not a duplicate,
1380 // so swap self[r] and self[w] and advance r and w:
1383 // +---+---+---+---+---+---+
1384 // | 0 | 1 | 2 | 1 | 3 | 3 |
1385 // +---+---+---+---+---+---+
1388 // Not a duplicate, repeat:
1391 // +---+---+---+---+---+---+
1392 // | 0 | 1 | 2 | 3 | 1 | 3 |
1393 // +---+---+---+---+---+---+
1396 // Duplicate, advance r. End of vec. Truncate to w.
1398 let ln = self.len();
1399 if ln < 1 { return; }
1401 // Avoid bounds checks by using unsafe pointers.
1402 let p = self.as_mut_slice().as_mut_ptr();
1407 let p_r = p.offset(r as int);
1408 let p_wm1 = p.offset((w - 1) as int);
1411 let p_w = p_wm1.offset(1);
1412 mem::swap(&mut *p_r, &mut *p_w);
1424 impl<T> Vector<T> for Vec<T> {
1425 /// Work with `self` as a slice.
1430 /// fn foo(slice: &[int]) {}
1432 /// let vec = vec!(1i, 2);
1433 /// foo(vec.as_slice());
1436 fn as_slice<'a>(&'a self) -> &'a [T] {
1437 unsafe { mem::transmute(Slice { data: self.as_ptr(), len: self.len }) }
1441 impl<T: Clone, V: Vector<T>> Add<V, Vec<T>> for Vec<T> {
1443 fn add(&self, rhs: &V) -> Vec<T> {
1444 let mut res = Vec::with_capacity(self.len() + rhs.as_slice().len());
1445 res.push_all(self.as_slice());
1446 res.push_all(rhs.as_slice());
1451 #[unsafe_destructor]
1452 impl<T> Drop for Vec<T> {
1453 fn drop(&mut self) {
1454 // This is (and should always remain) a no-op if the fields are
1455 // zeroed (when moving out, because of #[unsafe_no_drop_flag]).
1458 for x in self.as_mut_slice().iter() {
1461 dealloc(self.ptr, self.cap)
1467 impl<T> Default for Vec<T> {
1468 fn default() -> Vec<T> {
1473 impl<T:fmt::Show> fmt::Show for Vec<T> {
1474 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1475 self.as_slice().fmt(f)
1479 /// An iterator that moves out of a vector.
1480 pub struct MoveItems<T> {
1481 allocation: *mut T, // the block of memory allocated for the vector
1482 cap: uint, // the capacity of the vector
1483 iter: Items<'static, T>
1486 impl<T> Iterator<T> for MoveItems<T> {
1488 fn next(&mut self) -> Option<T> {
1490 self.iter.next().map(|x| ptr::read(x))
1495 fn size_hint(&self) -> (uint, Option<uint>) {
1496 self.iter.size_hint()
1500 impl<T> DoubleEndedIterator<T> for MoveItems<T> {
1502 fn next_back(&mut self) -> Option<T> {
1504 self.iter.next_back().map(|x| ptr::read(x))
1509 #[unsafe_destructor]
1510 impl<T> Drop for MoveItems<T> {
1511 fn drop(&mut self) {
1512 // destroy the remaining elements
1516 dealloc(self.allocation, self.cap);
1523 * Convert an iterator of pairs into a pair of vectors.
1525 * Returns a tuple containing two vectors where the i-th element of the first
1526 * vector contains the first element of the i-th tuple of the input iterator,
1527 * and the i-th element of the second vector contains the second element
1528 * of the i-th tuple of the input iterator.
1530 pub fn unzip<T, U, V: Iterator<(T, U)>>(mut iter: V) -> (Vec<T>, Vec<U>) {
1531 let (lo, _) = iter.size_hint();
1532 let mut ts = Vec::with_capacity(lo);
1533 let mut us = Vec::with_capacity(lo);
1534 for (t, u) in iter {
1541 /// Unsafe operations
1546 /// Constructs a vector from an unsafe pointer to a buffer.
1548 /// The elements of the buffer are copied into the vector without cloning,
1549 /// as if `ptr::read()` were called on them.
1551 pub unsafe fn from_buf<T>(ptr: *const T, elts: uint) -> Vec<T> {
1552 let mut dst = Vec::with_capacity(elts);
1554 ptr::copy_nonoverlapping_memory(dst.as_mut_ptr(), ptr, elts);
1564 use std::prelude::*;
1565 use std::mem::size_of;
1567 use super::{unzip, raw, Vec};
1570 fn test_small_vec_struct() {
1571 assert!(size_of::<Vec<u8>>() == size_of::<uint>() * 3);
1575 fn test_double_drop() {
1581 struct DropCounter<'a> {
1585 #[unsafe_destructor]
1586 impl<'a> Drop for DropCounter<'a> {
1587 fn drop(&mut self) {
1592 let mut count_x @ mut count_y = 0;
1594 let mut tv = TwoVec {
1598 tv.x.push(DropCounter {count: &mut count_x});
1599 tv.y.push(DropCounter {count: &mut count_y});
1601 // If Vec had a drop flag, here is where it would be zeroed.
1602 // Instead, it should rely on its internal state to prevent
1603 // doing anything significant when dropped multiple times.
1606 // Here tv goes out of scope, tv.y should be dropped, but not tv.x.
1609 assert_eq!(count_x, 1);
1610 assert_eq!(count_y, 1);
1614 fn test_reserve_additional() {
1615 let mut v = Vec::new();
1616 assert_eq!(v.capacity(), 0);
1618 v.reserve_additional(2);
1619 assert!(v.capacity() >= 2);
1621 for i in range(0i, 16) {
1625 assert!(v.capacity() >= 16);
1626 v.reserve_additional(16);
1627 assert!(v.capacity() >= 32);
1631 v.reserve_additional(16);
1632 assert!(v.capacity() >= 33)
1637 let mut v = Vec::new();
1638 let mut w = Vec::new();
1640 v.extend(range(0i, 3));
1641 for i in range(0i, 3) { w.push(i) }
1645 v.extend(range(3i, 10));
1646 for i in range(3i, 10) { w.push(i) }
1652 fn test_mut_slice_from() {
1653 let mut values = Vec::from_slice([1u8,2,3,4,5]);
1655 let slice = values.mut_slice_from(2);
1656 assert!(slice == [3, 4, 5]);
1657 for p in slice.mut_iter() {
1662 assert!(values.as_slice() == [1, 2, 5, 6, 7]);
1666 fn test_mut_slice_to() {
1667 let mut values = Vec::from_slice([1u8,2,3,4,5]);
1669 let slice = values.mut_slice_to(2);
1670 assert!(slice == [1, 2]);
1671 for p in slice.mut_iter() {
1676 assert!(values.as_slice() == [2, 3, 3, 4, 5]);
1680 fn test_mut_split_at() {
1681 let mut values = Vec::from_slice([1u8,2,3,4,5]);
1683 let (left, right) = values.mut_split_at(2);
1684 assert!(left.slice(0, left.len()) == [1, 2]);
1685 for p in left.mut_iter() {
1689 assert!(right.slice(0, right.len()) == [3, 4, 5]);
1690 for p in right.mut_iter() {
1695 assert!(values == Vec::from_slice([2u8, 3, 5, 6, 7]));
1700 let v: Vec<int> = vec!();
1701 let w = vec!(1i, 2, 3);
1703 assert_eq!(v, v.clone());
1707 // they should be disjoint in memory.
1708 assert!(w.as_ptr() != z.as_ptr())
1712 fn test_clone_from() {
1714 let three = vec!(box 1i, box 2, box 3);
1715 let two = vec!(box 4i, box 5);
1717 v.clone_from(&three);
1718 assert_eq!(v, three);
1721 v.clone_from(&three);
1722 assert_eq!(v, three);
1729 v.clone_from(&three);
1730 assert_eq!(v, three)
1735 let mut v = Vec::from_slice([0u, 1]);
1736 v.grow_fn(3, |i| i);
1737 assert!(v == Vec::from_slice([0u, 1, 0, 1, 2]));
1742 let mut vec = Vec::from_slice([1u, 2, 3, 4]);
1743 vec.retain(|x| x%2 == 0);
1744 assert!(vec == Vec::from_slice([2u, 4]));
1748 fn zero_sized_values() {
1749 let mut v = Vec::new();
1750 assert_eq!(v.len(), 0);
1752 assert_eq!(v.len(), 1);
1754 assert_eq!(v.len(), 2);
1755 assert_eq!(v.pop(), Some(()));
1756 assert_eq!(v.pop(), Some(()));
1757 assert_eq!(v.pop(), None);
1759 assert_eq!(v.iter().count(), 0);
1761 assert_eq!(v.iter().count(), 1);
1763 assert_eq!(v.iter().count(), 2);
1765 for &() in v.iter() {}
1767 assert_eq!(v.mut_iter().count(), 2);
1769 assert_eq!(v.mut_iter().count(), 3);
1771 assert_eq!(v.mut_iter().count(), 4);
1773 for &() in v.mut_iter() {}
1774 unsafe { v.set_len(0); }
1775 assert_eq!(v.mut_iter().count(), 0);
1779 fn test_partition() {
1780 assert_eq!(vec![].partition(|x: &int| *x < 3), (vec![], vec![]));
1781 assert_eq!(vec![1i, 2, 3].partition(|x: &int| *x < 4), (vec![1, 2, 3], vec![]));
1782 assert_eq!(vec![1i, 2, 3].partition(|x: &int| *x < 2), (vec![1], vec![2, 3]));
1783 assert_eq!(vec![1i, 2, 3].partition(|x: &int| *x < 0), (vec![], vec![1, 2, 3]));
1787 fn test_partitioned() {
1788 assert_eq!(vec![].partitioned(|x: &int| *x < 3), (vec![], vec![]))
1789 assert_eq!(vec![1i, 2, 3].partitioned(|x: &int| *x < 4), (vec![1, 2, 3], vec![]));
1790 assert_eq!(vec![1i, 2, 3].partitioned(|x: &int| *x < 2), (vec![1], vec![2, 3]));
1791 assert_eq!(vec![1i, 2, 3].partitioned(|x: &int| *x < 0), (vec![], vec![1, 2, 3]));
1795 fn test_zip_unzip() {
1796 let z1 = vec![(1i, 4i), (2, 5), (3, 6)];
1798 let (left, right) = unzip(z1.iter().map(|&x| x));
1800 let (left, right) = (left.as_slice(), right.as_slice());
1801 assert_eq!((1, 4), (left[0], right[0]));
1802 assert_eq!((2, 5), (left[1], right[1]));
1803 assert_eq!((3, 6), (left[2], right[2]));
1807 fn test_unsafe_ptrs() {
1809 // Test on-stack copy-from-buf.
1811 let ptr = a.as_ptr();
1812 let b = raw::from_buf(ptr, 3u);
1813 assert_eq!(b, vec![1, 2, 3]);
1815 // Test on-heap copy-from-buf.
1816 let c = vec![1i, 2, 3, 4, 5];
1817 let ptr = c.as_ptr();
1818 let d = raw::from_buf(ptr, 5u);
1819 assert_eq!(d, vec![1, 2, 3, 4, 5]);
1824 fn test_vec_truncate_drop() {
1825 static mut drops: uint = 0;
1827 impl Drop for Elem {
1828 fn drop(&mut self) {
1829 unsafe { drops += 1; }
1833 let mut v = vec![Elem(1), Elem(2), Elem(3), Elem(4), Elem(5)];
1834 assert_eq!(unsafe { drops }, 0);
1836 assert_eq!(unsafe { drops }, 2);
1838 assert_eq!(unsafe { drops }, 5);
1843 fn test_vec_truncate_fail() {
1844 struct BadElem(int);
1845 impl Drop for BadElem {
1846 fn drop(&mut self) {
1847 let BadElem(ref mut x) = *self;
1848 if *x == 0xbadbeef {
1849 fail!("BadElem failure: 0xbadbeef")
1854 let mut v = vec![BadElem(1), BadElem(2), BadElem(0xbadbeef), BadElem(4)];
1859 fn bench_new(b: &mut Bencher) {
1861 let v: Vec<int> = Vec::new();
1862 assert_eq!(v.capacity(), 0);
1863 assert!(v.as_slice() == []);
1868 fn bench_with_capacity_0(b: &mut Bencher) {
1870 let v: Vec<int> = Vec::with_capacity(0);
1871 assert_eq!(v.capacity(), 0);
1872 assert!(v.as_slice() == []);
1878 fn bench_with_capacity_5(b: &mut Bencher) {
1880 let v: Vec<int> = Vec::with_capacity(5);
1881 assert_eq!(v.capacity(), 5);
1882 assert!(v.as_slice() == []);
1887 fn bench_with_capacity_100(b: &mut Bencher) {
1889 let v: Vec<int> = Vec::with_capacity(100);
1890 assert_eq!(v.capacity(), 100);
1891 assert!(v.as_slice() == []);
1896 fn bench_from_fn_0(b: &mut Bencher) {
1898 let v: Vec<int> = Vec::from_fn(0, |_| 5);
1899 assert!(v.as_slice() == []);
1904 fn bench_from_fn_5(b: &mut Bencher) {
1906 let v: Vec<int> = Vec::from_fn(5, |_| 5);
1907 assert!(v.as_slice() == [5, 5, 5, 5, 5]);
1912 fn bench_from_slice_0(b: &mut Bencher) {
1914 let v: Vec<int> = Vec::from_slice([]);
1915 assert!(v.as_slice() == []);
1920 fn bench_from_slice_5(b: &mut Bencher) {
1922 let v: Vec<int> = Vec::from_slice([1i, 2, 3, 4, 5]);
1923 assert!(v.as_slice() == [1, 2, 3, 4, 5]);
1928 fn bench_from_iter_0(b: &mut Bencher) {
1930 let v0: Vec<int> = vec!();
1931 let v1: Vec<int> = FromIterator::from_iter(v0.move_iter());
1932 assert!(v1.as_slice() == []);
1937 fn bench_from_iter_5(b: &mut Bencher) {
1939 let v0: Vec<int> = vec!(1, 2, 3, 4, 5);
1940 let v1: Vec<int> = FromIterator::from_iter(v0.move_iter());
1941 assert!(v1.as_slice() == [1, 2, 3, 4, 5]);
1946 fn bench_extend_0(b: &mut Bencher) {
1948 let v0: Vec<int> = vec!();
1949 let mut v1: Vec<int> = vec!(1, 2, 3, 4, 5);
1950 v1.extend(v0.move_iter());
1951 assert!(v1.as_slice() == [1, 2, 3, 4, 5]);
1956 fn bench_extend_5(b: &mut Bencher) {
1958 let v0: Vec<int> = vec!(1, 2, 3, 4, 5);
1959 let mut v1: Vec<int> = vec!(1, 2, 3, 4, 5);
1960 v1.extend(v0.move_iter());
1961 assert!(v1.as_slice() == [1, 2, 3, 4, 5, 1, 2, 3, 4, 5]);