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at_vec.rs
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/
at_vec.rs
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// Copyright 2012 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.
//! Operations on managed vectors (`@[T]` type)
use clone::Clone;
use container::Container;
use iter::{Iterator, FromIterator};
use option::{Option, Some, None};
use mem;
use unstable::raw::Repr;
use vec::{ImmutableVector, OwnedVector};
/// Code for dealing with @-vectors. This is pretty incomplete, and
/// contains a bunch of duplication from the code for ~-vectors.
/// Returns the number of elements the vector can hold without reallocating
#[inline]
pub fn capacity<T>(v: @[T]) -> uint {
unsafe {
let managed_box = v.repr();
(*managed_box).data.alloc / mem::size_of::<T>()
}
}
/**
* Builds a vector by calling a provided function with an argument
* function that pushes an element to the back of a vector.
* The initial size for the vector may optionally be specified
*
* # Arguments
*
* * size - An option, maybe containing initial size of the vector to reserve
* * builder - A function that will construct the vector. It receives
* as an argument a function that will push an element
* onto the vector being constructed.
*/
#[inline]
pub fn build<A>(size: Option<uint>, builder: |push: |v: A||) -> @[A] {
let mut vec = @[];
unsafe { raw::reserve(&mut vec, size.unwrap_or(4)); }
builder(|x| unsafe { raw::push(&mut vec, x) });
vec
}
// Appending
/// Iterates over the `rhs` vector, copying each element and appending it to the
/// `lhs`. Afterwards, the `lhs` is then returned for use again.
#[inline]
pub fn append<T:Clone>(lhs: @[T], rhs: &[T]) -> @[T] {
build(Some(lhs.len() + rhs.len()), |push| {
for x in lhs.iter() {
push((*x).clone());
}
for elt in rhs.iter() {
push(elt.clone());
}
})
}
/// Apply a function to each element of a vector and return the results
#[inline]
pub fn map<T, U>(v: &[T], f: |x: &T| -> U) -> @[U] {
build(Some(v.len()), |push| {
for elem in v.iter() {
push(f(elem));
}
})
}
/**
* Creates and initializes an immutable vector.
*
* Creates an immutable vector of size `n_elts` and initializes the elements
* to the value returned by the function `op`.
*/
#[inline]
pub fn from_fn<T>(n_elts: uint, op: |uint| -> T) -> @[T] {
build(Some(n_elts), |push| {
let mut i: uint = 0u;
while i < n_elts { push(op(i)); i += 1u; }
})
}
/**
* Creates and initializes an immutable vector.
*
* Creates an immutable vector of size `n_elts` and initializes the elements
* to the value `t`.
*/
#[inline]
pub fn from_elem<T:Clone>(n_elts: uint, t: T) -> @[T] {
build(Some(n_elts), |push| {
let mut i: uint = 0u;
while i < n_elts {
push(t.clone());
i += 1u;
}
})
}
/**
* Creates and initializes an immutable managed vector by moving all the
* elements from an owned vector.
*/
#[inline]
pub fn to_managed_move<T>(v: ~[T]) -> @[T] {
let mut av = @[];
unsafe {
raw::reserve(&mut av, v.len());
for x in v.move_iter() {
raw::push(&mut av, x);
}
av
}
}
/**
* Creates and initializes an immutable managed vector by copying all the
* elements of a slice.
*/
#[inline]
pub fn to_managed<T:Clone>(v: &[T]) -> @[T] {
from_fn(v.len(), |i| v[i].clone())
}
impl<T> Clone for @[T] {
fn clone(&self) -> @[T] {
*self
}
}
impl<A> FromIterator<A> for @[A] {
#[inline]
fn from_iterator<T: Iterator<A>>(iterator: &mut T) -> @[A] {
let (lower, _) = iterator.size_hint();
build(Some(lower), |push| {
for x in *iterator {
push(x);
}
})
}
}
#[cfg(not(test))]
#[allow(missing_doc)]
pub mod traits {
use at_vec::append;
use clone::Clone;
use ops::Add;
use vec::Vector;
impl<'a,T:Clone, V: Vector<T>> Add<V,@[T]> for @[T] {
#[inline]
fn add(&self, rhs: &V) -> @[T] {
append(*self, rhs.as_slice())
}
}
}
#[cfg(test)]
pub mod traits {}
#[allow(missing_doc)]
pub mod raw {
use at_vec::capacity;
use cast;
use cast::{transmute, transmute_copy};
use container::Container;
use option::None;
use ptr;
use mem;
use uint;
use unstable::intrinsics::{move_val_init, TyDesc};
use unstable::intrinsics;
use unstable::raw::{Box, Vec};
/**
* Sets the length of a vector
*
* This will explicitly set the size of the vector, without actually
* modifying its buffers, so it is up to the caller to ensure that
* the vector is actually the specified size.
*/
#[inline]
pub unsafe fn set_len<T>(v: &mut @[T], new_len: uint) {
let repr: *mut Box<Vec<T>> = cast::transmute_copy(v);
(*repr).data.fill = new_len * mem::size_of::<T>();
}
/**
* Pushes a new value onto this vector.
*/
#[inline]
pub unsafe fn push<T>(v: &mut @[T], initval: T) {
let full = {
let repr: *Box<Vec<T>> = cast::transmute_copy(v);
(*repr).data.alloc > (*repr).data.fill
};
if full {
push_fast(v, initval);
} else {
push_slow(v, initval);
}
}
#[inline] // really pretty please
unsafe fn push_fast<T>(v: &mut @[T], initval: T) {
let repr: *mut Box<Vec<T>> = cast::transmute_copy(v);
let amt = v.len();
(*repr).data.fill += mem::size_of::<T>();
let p = ptr::offset(&(*repr).data.data as *T, amt as int) as *mut T;
move_val_init(&mut(*p), initval);
}
#[inline]
unsafe fn push_slow<T>(v: &mut @[T], initval: T) {
reserve_at_least(v, v.len() + 1u);
push_fast(v, initval);
}
/**
* Reserves capacity for exactly `n` elements in the given vector.
*
* If the capacity for `v` is already equal to or greater than the
* requested capacity, then no action is taken.
*
* # Arguments
*
* * v - A vector
* * n - The number of elements to reserve space for
*/
#[inline]
pub unsafe fn reserve<T>(v: &mut @[T], n: uint) {
// Only make the (slow) call into the runtime if we have to
if capacity(*v) < n {
let ptr: *mut *mut Box<Vec<()>> = transmute(v);
let ty = intrinsics::get_tydesc::<T>();
return reserve_raw(ty, ptr, n);
}
}
// Implementation detail. Shouldn't be public
#[allow(missing_doc)]
#[inline]
pub fn reserve_raw(ty: *TyDesc, ptr: *mut *mut Box<Vec<()>>, n: uint) {
// check for `uint` overflow
unsafe {
if n > (**ptr).data.alloc / (*ty).size {
let alloc = n * (*ty).size;
let total_size = alloc + mem::size_of::<Vec<()>>();
if alloc / (*ty).size != n || total_size < alloc {
fail!("vector size is too large: {}", n);
}
(*ptr) = local_realloc(*ptr as *(), total_size) as *mut Box<Vec<()>>;
(**ptr).data.alloc = alloc;
}
}
#[inline]
fn local_realloc(ptr: *(), size: uint) -> *() {
use rt::local::Local;
use rt::task::Task;
let mut task = Local::borrow(None::<Task>);
task.get().heap.realloc(ptr as *mut Box<()>, size) as *()
}
}
/**
* Reserves capacity for at least `n` elements in the given vector.
*
* This function will over-allocate in order to amortize the
* allocation costs in scenarios where the caller may need to
* repeatedly reserve additional space.
*
* If the capacity for `v` is already equal to or greater than the
* requested capacity, then no action is taken.
*
* # Arguments
*
* * v - A vector
* * n - The number of elements to reserve space for
*/
#[inline]
pub unsafe fn reserve_at_least<T>(v: &mut @[T], n: uint) {
reserve(v, uint::next_power_of_two(n));
}
}
#[cfg(test)]
mod test {
use super::*;
use prelude::*;
use bh = extra::test::BenchHarness;
#[test]
fn test() {
// Some code that could use that, then:
fn seq_range(lo: uint, hi: uint) -> @[uint] {
build(None, |push| {
for i in range(lo, hi) {
push(i);
}
})
}
assert_eq!(seq_range(10, 15), @[10, 11, 12, 13, 14]);
assert_eq!(from_fn(5, |x| x+1), @[1, 2, 3, 4, 5]);
assert_eq!(from_elem(5, 3.14), @[3.14, 3.14, 3.14, 3.14, 3.14]);
}
#[test]
fn append_test() {
assert_eq!(@[1,2,3] + &[4,5,6], @[1,2,3,4,5,6]);
}
#[test]
fn test_to_managed_move() {
assert_eq!(to_managed_move::<int>(~[]), @[]);
assert_eq!(to_managed_move(~[true]), @[true]);
assert_eq!(to_managed_move(~[1, 2, 3, 4, 5]), @[1, 2, 3, 4, 5]);
assert_eq!(to_managed_move(~[~"abc", ~"123"]), @[~"abc", ~"123"]);
assert_eq!(to_managed_move(~[~[42]]), @[~[42]]);
}
#[test]
fn test_to_managed() {
assert_eq!(to_managed::<int>([]), @[]);
assert_eq!(to_managed([true]), @[true]);
assert_eq!(to_managed([1, 2, 3, 4, 5]), @[1, 2, 3, 4, 5]);
assert_eq!(to_managed([@"abc", @"123"]), @[@"abc", @"123"]);
assert_eq!(to_managed([@[42]]), @[@[42]]);
}
#[bench]
fn bench_capacity(b: &mut bh) {
let x = @[1, 2, 3];
b.iter(|| {
let _ = capacity(x);
});
}
#[bench]
fn bench_build_sized(b: &mut bh) {
let len = 64;
b.iter(|| {
build(Some(len), |push| for i in range(0, 1024) { push(i) });
});
}
#[bench]
fn bench_build(b: &mut bh) {
b.iter(|| {
for i in range(0, 95) {
build(None, |push| push(i));
}
});
}
#[bench]
fn bench_append(b: &mut bh) {
let lhs = @[7, ..128];
let rhs = range(0, 256).to_owned_vec();
b.iter(|| {
let _ = append(lhs, rhs);
})
}
#[bench]
fn bench_map(b: &mut bh) {
let elts = range(0, 256).to_owned_vec();
b.iter(|| {
let _ = map(elts, |x| x*2);
})
}
#[bench]
fn bench_from_fn(b: &mut bh) {
b.iter(|| {
let _ = from_fn(1024, |x| x);
});
}
#[bench]
fn bench_from_elem(b: &mut bh) {
b.iter(|| {
let _ = from_elem(1024, 0u64);
});
}
#[bench]
fn bench_to_managed_move(b: &mut bh) {
b.iter(|| {
let elts = range(0, 1024).to_owned_vec(); // yikes! can't move out of capture, though
to_managed_move(elts);
})
}
#[bench]
fn bench_to_managed(b: &mut bh) {
let elts = range(0, 1024).to_owned_vec();
b.iter(|| {
let _ = to_managed(elts);
});
}
#[bench]
fn bench_clone(b: &mut bh) {
let elts = to_managed(range(0, 1024).to_owned_vec());
b.iter(|| {
let _ = elts.clone();
});
}
}