65 lines
1.8 KiB
Rust
65 lines
1.8 KiB
Rust
// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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use std::fmt;
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use std::ops::{Deref, Range};
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use std::rc::Rc;
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use rustc_data_structures::stable_hasher::{StableHasher, StableHasherResult,
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HashStable};
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#[derive(Clone)]
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pub struct RcSlice<T> {
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data: Rc<Box<[T]>>,
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offset: u32,
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len: u32,
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}
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impl<T> RcSlice<T> {
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pub fn new(vec: Vec<T>) -> Self {
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RcSlice {
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offset: 0,
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len: vec.len() as u32,
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data: Rc::new(vec.into_boxed_slice()),
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}
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}
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pub fn sub_slice(&self, range: Range<usize>) -> Self {
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RcSlice {
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data: self.data.clone(),
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offset: self.offset + range.start as u32,
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len: (range.end - range.start) as u32,
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}
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}
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}
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impl<T> Deref for RcSlice<T> {
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type Target = [T];
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fn deref(&self) -> &[T] {
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&self.data[self.offset as usize .. (self.offset + self.len) as usize]
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}
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}
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impl<T: fmt::Debug> fmt::Debug for RcSlice<T> {
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fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
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fmt::Debug::fmt(self.deref(), f)
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}
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}
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impl<CTX, T> HashStable<CTX> for RcSlice<T>
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where T: HashStable<CTX>
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{
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fn hash_stable<W: StableHasherResult>(&self,
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hcx: &mut CTX,
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hasher: &mut StableHasher<W>) {
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(**self).hash_stable(hcx, hasher);
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}
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}
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