bjoernager/rust
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use element count in slices, not size in bytes

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This allows the indexing bounds check or other comparisons against an
element length to avoid a multiplication by the size.
This commit is contained in:
Daniel Micay 2013-10-15 00:37:32 -04:00
parent aa93381e14
commit e1a26ad271
10 changed files with 154 additions and 76 deletions
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81
src/libstd/vec.rs
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@ -974,6 +974,7 @@ pub trait ImmutableVector<'self, T> {
impl<'self,T> ImmutableVector<'self, T> for &'self [T] {
#[inline]
#[cfg(stage0)]
fn slice(&self, start: uint, end: uint) -> &'self [T] {
assert!(start <= end);
assert!(end <= self.len());
@ -986,10 +987,27 @@ impl<'self,T> ImmutableVector<'self, T> for &'self [T] {
}
}
}
#[inline]
#[cfg(not(stage0))]
fn slice(&self, start: uint, end: uint) -> &'self [T] {
assert!(start <= end);
assert!(end <= self.len());
do self.as_imm_buf |p, _len| {
unsafe {
cast::transmute(Slice {
data: ptr::offset(p, start as int),
len: (end - start)
})
}
}
}
#[inline]
fn slice_from(&self, start: uint) -> &'self [T] {
self.slice(start, self.len())
}
#[inline]
fn slice_to(&self, end: uint) -> &'self [T] {
self.slice(0, end)
@ -1130,10 +1148,18 @@ impl<'self,T> ImmutableVector<'self, T> for &'self [T] {
}
#[inline]
#[cfg(stage0)]
fn as_imm_buf<U>(&self, f: &fn(*T, uint) -> U) -> U {
let s = self.repr();
f(s.data, s.len / sys::nonzero_size_of::<T>())
}
#[inline]
#[cfg(not(stage0))]
fn as_imm_buf<U>(&self, f: &fn(*T, uint) -> U) -> U {
let s = self.repr();
f(s.data, s.len)
}
}
/// Extension methods for vectors contain `Eq` elements.
@ -1899,6 +1925,7 @@ pub trait MutableVector<'self, T> {
impl<'self,T> MutableVector<'self, T> for &'self mut [T] {
#[inline]
#[cfg(stage0)]
fn mut_slice(self, start: uint, end: uint) -> &'self mut [T] {
assert!(start <= end);
assert!(end <= self.len());
@ -1912,6 +1939,21 @@ impl<'self,T> MutableVector<'self, T> for &'self mut [T] {
}
}
#[inline]
#[cfg(not(stage0))]
fn mut_slice(self, start: uint, end: uint) -> &'self mut [T] {
assert!(start <= end);
assert!(end <= self.len());
do self.as_mut_buf |p, _len| {
unsafe {
cast::transmute(Slice {
data: ptr::mut_offset(p, start as int) as *T,
len: (end - start)
})
}
}
}
#[inline]
fn mut_slice_from(self, start: uint) -> &'self mut [T] {
let len = self.len();
@ -1991,11 +2033,18 @@ impl<'self,T> MutableVector<'self, T> for &'self mut [T] {
}
#[inline]
#[cfg(stage0)]
fn as_mut_buf<U>(self, f: &fn(*mut T, uint) -> U) -> U {
let Slice{ data, len } = self.repr();
f(data as *mut T, len / sys::nonzero_size_of::<T>())
}
#[inline]
#[cfg(not(stage0))]
fn as_mut_buf<U>(self, f: &fn(*mut T, uint) -> U) -> U {
let Slice{ data, len } = self.repr();
f(data as *mut T, len)
}
}
/// Trait for &[T] where T is Cloneable
@ -2083,6 +2132,7 @@ pub mod raw {
* not bytes).
*/
#[inline]
#[cfg(stage0)]
pub unsafe fn buf_as_slice<T,U>(p: *T,
len: uint,
f: &fn(v: &[T]) -> U) -> U {
@ -2097,6 +2147,22 @@ pub mod raw {
* not bytes).
*/
#[inline]
#[cfg(not(stage0))]
pub unsafe fn buf_as_slice<T,U>(p: *T,
len: uint,
f: &fn(v: &[T]) -> U) -> U {
f(cast::transmute(Slice {
data: p,
len: len
}))
}
/**
* Form a slice from a pointer and length (as a number of units,
* not bytes).
*/
#[inline]
#[cfg(stage0)]
pub unsafe fn mut_buf_as_slice<T,U>(p: *mut T,
len: uint,
f: &fn(v: &mut [T]) -> U) -> U {
@ -2106,6 +2172,21 @@ pub mod raw {
}))
}
/**
* Form a slice from a pointer and length (as a number of units,
* not bytes).
*/
#[inline]
#[cfg(not(stage0))]
pub unsafe fn mut_buf_as_slice<T,U>(p: *mut T,
len: uint,
f: &fn(v: &mut [T]) -> U) -> U {
f(cast::transmute(Slice {
data: p as *T,
len: len
}))
}
/**
* Unchecked vector indexing.
*/