diff --git a/src/libcore/slice.rs b/src/libcore/slice.rs index f765cdc54d89b..6513c49a06ea7 100644 --- a/src/libcore/slice.rs +++ b/src/libcore/slice.rs @@ -51,6 +51,7 @@ use ptr; use mem; use mem::size_of; use marker::{Send, Sync, self}; +use num::wrapping::OverflowingOps; use raw::Repr; // Avoid conflicts with *both* the Slice trait (buggy) and the `slice::raw` module. use raw::Slice as RawSlice; @@ -1183,6 +1184,34 @@ impl<'a, T> Iterator for Windows<'a, T> { (size, Some(size)) } } + + #[inline] + fn count(self) -> usize { + self.size_hint().0 + } + + #[inline] + fn nth(&mut self, n: usize) -> Option { + let (end, overflow) = self.size.overflowing_add(n); + if end > self.v.len() || overflow { + self.v = &[]; + None + } else { + let nth = &self.v[n..end]; + self.v = &self.v[n+1..]; + Some(nth) + } + } + + #[inline] + fn last(self) -> Option { + if self.size > self.v.len() { + None + } else { + let start = self.v.len() - self.size; + Some(&self.v[start..]) + } + } } #[stable(feature = "rust1", since = "1.0.0")] @@ -1269,6 +1298,38 @@ impl<'a, T> Iterator for Chunks<'a, T> { (n, Some(n)) } } + + #[inline] + fn count(self) -> usize { + self.size_hint().0 + } + + #[inline] + fn nth(&mut self, n: usize) -> Option { + let (start, overflow) = n.overflowing_mul(self.size); + if start >= self.v.len() || overflow { + self.v = &[]; + None + } else { + let end = match start.checked_add(self.size) { + Some(sum) => cmp::min(self.v.len(), sum), + None => self.v.len(), + }; + let nth = &self.v[start..end]; + self.v = &self.v[end..]; + Some(nth) + } + } + + #[inline] + fn last(self) -> Option { + if self.v.is_empty() { + None + } else { + let start = (self.v.len() - 1) / self.size * self.size; + Some(&self.v[start..]) + } + } } #[stable(feature = "rust1", since = "1.0.0")] @@ -1349,6 +1410,40 @@ impl<'a, T> Iterator for ChunksMut<'a, T> { (n, Some(n)) } } + + #[inline] + fn count(self) -> usize { + self.size_hint().0 + } + + #[inline] + fn nth(&mut self, n: usize) -> Option<&'a mut [T]> { + let (start, overflow) = n.overflowing_mul(self.chunk_size); + if start >= self.v.len() || overflow { + self.v = &mut []; + None + } else { + let end = match start.checked_add(self.chunk_size) { + Some(sum) => cmp::min(self.v.len(), sum), + None => self.v.len(), + }; + let tmp = mem::replace(&mut self.v, &mut []); + let (head, tail) = tmp.split_at_mut(end); + let (_, nth) = head.split_at_mut(start); + self.v = tail; + Some(nth) + } + } + + #[inline] + fn last(self) -> Option { + if self.v.is_empty() { + None + } else { + let start = (self.v.len() - 1) / self.chunk_size * self.chunk_size; + Some(&mut self.v[start..]) + } + } } #[stable(feature = "rust1", since = "1.0.0")] diff --git a/src/libcoretest/slice.rs b/src/libcoretest/slice.rs index 5a1166aeb5085..d60eeb76ccd4a 100644 --- a/src/libcoretest/slice.rs +++ b/src/libcoretest/slice.rs @@ -64,3 +64,123 @@ fn test_iterator_count() { iter2.next(); assert_eq!(iter2.count(), 3); } + +#[test] +fn test_chunks_count() { + let v: &[i32] = &[0, 1, 2, 3, 4, 5]; + let c = v.chunks(3); + assert_eq!(c.count(), 2); + + let v2: &[i32] = &[0, 1, 2, 3, 4]; + let c2 = v2.chunks(2); + assert_eq!(c2.count(), 3); + + let v3: &[i32] = &[]; + let c3 = v3.chunks(2); + assert_eq!(c3.count(), 0); +} + +#[test] +fn test_chunks_nth() { + let v: &[i32] = &[0, 1, 2, 3, 4, 5]; + let mut c = v.chunks(2); + assert_eq!(c.nth(1).unwrap()[1], 3); + assert_eq!(c.next().unwrap()[0], 4); + + let v2: &[i32] = &[0, 1, 2, 3, 4]; + let mut c2 = v2.chunks(3); + assert_eq!(c2.nth(1).unwrap()[1], 4); + assert_eq!(c2.next(), None); +} + +#[test] +fn test_chunks_last() { + let v: &[i32] = &[0, 1, 2, 3, 4, 5]; + let c = v.chunks(2); + assert_eq!(c.last().unwrap()[1], 5); + + let v2: &[i32] = &[0, 1, 2, 3, 4]; + let c2 = v2.chunks(2); + assert_eq!(c2.last().unwrap()[0], 4); +} + +#[test] +fn test_chunks_mut_count() { + let mut v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5]; + let c = v.chunks_mut(3); + assert_eq!(c.count(), 2); + + let mut v2: &mut [i32] = &mut [0, 1, 2, 3, 4]; + let c2 = v2.chunks_mut(2); + assert_eq!(c2.count(), 3); + + let mut v3: &mut [i32] = &mut []; + let c3 = v3.chunks_mut(2); + assert_eq!(c3.count(), 0); +} + +#[test] +fn test_chunks_mut_nth() { + let mut v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5]; + let mut c = v.chunks_mut(2); + assert_eq!(c.nth(1).unwrap()[1], 3); + assert_eq!(c.next().unwrap()[0], 4); + + let mut v2: &mut [i32] = &mut [0, 1, 2, 3, 4]; + let mut c2 = v2.chunks_mut(3); + assert_eq!(c2.nth(1).unwrap()[1], 4); + assert_eq!(c2.next(), None); +} + +#[test] +fn test_chunks_mut_last() { + let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5]; + let c = v.chunks_mut(2); + assert_eq!(c.last().unwrap()[1], 5); + + let v2: &mut [i32] = &mut [0, 1, 2, 3, 4]; + let c2 = v2.chunks_mut(2); + assert_eq!(c2.last().unwrap()[0], 4); +} + + + + +#[test] +fn test_windows_count() { + let v: &[i32] = &[0, 1, 2, 3, 4, 5]; + let c = v.windows(3); + assert_eq!(c.count(), 4); + + let v2: &[i32] = &[0, 1, 2, 3, 4]; + let c2 = v2.windows(6); + assert_eq!(c2.count(), 0); + + let v3: &[i32] = &[]; + let c3 = v3.windows(2); + assert_eq!(c3.count(), 0); +} + +#[test] +fn test_windows_nth() { + let v: &[i32] = &[0, 1, 2, 3, 4, 5]; + let mut c = v.windows(2); + assert_eq!(c.nth(2).unwrap()[1], 3); + assert_eq!(c.next().unwrap()[0], 3); + + let v2: &[i32] = &[0, 1, 2, 3, 4]; + let mut c2 = v2.windows(4); + assert_eq!(c2.nth(1).unwrap()[1], 2); + assert_eq!(c2.next(), None); +} + +#[test] +fn test_windows_last() { + let v: &[i32] = &[0, 1, 2, 3, 4, 5]; + let c = v.windows(2); + assert_eq!(c.last().unwrap()[1], 5); + + let v2: &[i32] = &[0, 1, 2, 3, 4]; + let c2 = v2.windows(2); + assert_eq!(c2.last().unwrap()[0], 3); +}