1 // Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
4 //
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
10 use core::{
11 fmt::{self, Write},
12 iter::FusedIterator,
13 };
14 use tinyvec::ArrayVec;
15
16 /// External iterator for replacements for a string's characters.
17 #[derive(Clone)]
18 pub struct Replacements<I> {
19 iter: I,
20 // At this time, the longest replacement sequence has length 2, so we just
21 // need buffer space for 1 codepoint.
22 buffer: Option<char>,
23 }
24
25 #[inline]
new_cjk_compat_variants<I: Iterator<Item = char>>(iter: I) -> Replacements<I>26 pub fn new_cjk_compat_variants<I: Iterator<Item = char>>(iter: I) -> Replacements<I> {
27 Replacements { iter, buffer: None }
28 }
29
30 impl<I: Iterator<Item = char>> Iterator for Replacements<I> {
31 type Item = char;
32
33 #[inline]
next(&mut self) -> Option<char>34 fn next(&mut self) -> Option<char> {
35 if let Some(c) = self.buffer.take() {
36 return Some(c);
37 }
38
39 match self.iter.next() {
40 Some(ch) => {
41 // At this time, the longest replacement sequence has length 2.
42 let mut buffer = ArrayVec::<[char; 2]>::new();
43 super::char::decompose_cjk_compat_variants(ch, |d| buffer.push(d));
44 self.buffer = buffer.get(1).copied();
45 Some(buffer[0])
46 }
47 None => None,
48 }
49 }
50
size_hint(&self) -> (usize, Option<usize>)51 fn size_hint(&self) -> (usize, Option<usize>) {
52 let (lower, _) = self.iter.size_hint();
53 (lower, None)
54 }
55 }
56
57 impl<I: Iterator<Item = char> + FusedIterator> FusedIterator for Replacements<I> {}
58
59 impl<I: Iterator<Item = char> + Clone> fmt::Display for Replacements<I> {
fmt(&self, f: &mut fmt::Formatter) -> fmt::Result60 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
61 for c in self.clone() {
62 f.write_char(c)?;
63 }
64 Ok(())
65 }
66 }
67