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fix(rustup): Add some missing files
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erickt committed Dec 7, 2015
1 parent 4e90ed6 commit b4b2a55
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71 changes: 71 additions & 0 deletions syntex_syntax/src/util/lev_distance.rs
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// Copyright 2012-2014 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.

use std::cmp;

pub fn lev_distance(me: &str, t: &str) -> usize {
if me.is_empty() { return t.chars().count(); }
if t.is_empty() { return me.chars().count(); }

let mut dcol: Vec<_> = (0..t.len() + 1).collect();
let mut t_last = 0;

for (i, sc) in me.chars().enumerate() {

let mut current = i;
dcol[0] = current + 1;

for (j, tc) in t.chars().enumerate() {

let next = dcol[j + 1];

if sc == tc {
dcol[j + 1] = current;
} else {
dcol[j + 1] = cmp::min(current, next);
dcol[j + 1] = cmp::min(dcol[j + 1], dcol[j]) + 1;
}

current = next;
t_last = j;
}
}

dcol[t_last + 1]
}

pub fn max_suggestion_distance(name: &str) -> usize {
use std::cmp::max;
// As a loose rule to avoid obviously incorrect suggestions, clamp the
// maximum edit distance we will accept for a suggestion to one third of
// the typo'd name's length.
max(name.len(), 3) / 3
}

#[test]
fn test_lev_distance() {
use std::char::{ from_u32, MAX };
// Test bytelength agnosticity
for c in (0..MAX as u32)
.filter_map(|i| from_u32(i))
.map(|i| i.to_string()) {
assert_eq!(lev_distance(&c[..], &c[..]), 0);
}

let a = "\nMäry häd ä little lämb\n\nLittle lämb\n";
let b = "\nMary häd ä little lämb\n\nLittle lämb\n";
let c = "Mary häd ä little lämb\n\nLittle lämb\n";
assert_eq!(lev_distance(a, b), 1);
assert_eq!(lev_distance(b, a), 1);
assert_eq!(lev_distance(a, c), 2);
assert_eq!(lev_distance(c, a), 2);
assert_eq!(lev_distance(b, c), 1);
assert_eq!(lev_distance(c, b), 1);
}
79 changes: 79 additions & 0 deletions syntex_syntax/src/util/move_map.rs
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// Copyright 2015 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.

use owned_slice::OwnedSlice;

use std::ptr;

pub trait MoveMap<T>: Sized {
fn move_map<F>(self, mut f: F) -> Self where F: FnMut(T) -> T {
self.move_flat_map(|e| Some(f(e)))
}

fn move_flat_map<F, I>(self, f: F) -> Self
where F: FnMut(T) -> I,
I: IntoIterator<Item=T>;
}

impl<T> MoveMap<T> for Vec<T> {
fn move_flat_map<F, I>(mut self, mut f: F) -> Self
where F: FnMut(T) -> I,
I: IntoIterator<Item=T>
{
let mut read_i = 0;
let mut write_i = 0;
unsafe {
let mut old_len = self.len();
self.set_len(0); // make sure we just leak elements in case of panic

while read_i < old_len {
// move the read_i'th item out of the vector and map it
// to an iterator
let e = ptr::read(self.get_unchecked(read_i));
let mut iter = f(e).into_iter();
read_i += 1;

while let Some(e) = iter.next() {
if write_i < read_i {
ptr::write(self.get_unchecked_mut(write_i), e);
write_i += 1;
} else {
// If this is reached we ran out of space
// in the middle of the vector.
// However, the vector is in a valid state here,
// so we just do a somewhat inefficient insert.
self.set_len(old_len);
self.insert(write_i, e);

old_len = self.len();
self.set_len(0);

read_i += 1;
write_i += 1;
}
}
}

// write_i tracks the number of actually written new items.
self.set_len(write_i);
}

self
}
}

impl<T> MoveMap<T> for OwnedSlice<T> {
fn move_flat_map<F, I>(self, f: F) -> Self
where F: FnMut(T) -> I,
I: IntoIterator<Item=T>
{
OwnedSlice::from_vec(self.into_vec().move_flat_map(f))
}
}

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