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::fmt::{self, Write};
11 use tinyvec::ArrayVec;
12
13 /// External iterator for replacements for a string's characters.
14 #[derive(Clone)]
15 pub struct Replacements<I> {
16 iter: I,
17 // At this time, the longest replacement sequence has length 2, so we just
18 // need buffer space for 1 codepoint.
19 buffer: Option<char>,
20 }
21
22 #[inline]
new_cjk_compat_variants<I: Iterator<Item = char>>(iter: I) -> Replacements<I>23 pub fn new_cjk_compat_variants<I: Iterator<Item = char>>(iter: I) -> Replacements<I> {
24 Replacements { iter, buffer: None }
25 }
26
27 impl<I: Iterator<Item = char>> Iterator for Replacements<I> {
28 type Item = char;
29
30 #[inline]
next(&mut self) -> Option<char>31 fn next(&mut self) -> Option<char> {
32 if let Some(c) = self.buffer.take() {
33 return Some(c);
34 }
35
36 match self.iter.next() {
37 Some(ch) => {
38 // At this time, the longest replacement sequence has length 2.
39 let mut buffer = ArrayVec::<[char; 2]>::new();
40 super::char::decompose_cjk_compat_variants(ch, |d| buffer.push(d));
41 self.buffer = buffer.get(1).copied();
42 Some(buffer[0])
43 }
44 None => None,
45 }
46 }
47
size_hint(&self) -> (usize, Option<usize>)48 fn size_hint(&self) -> (usize, Option<usize>) {
49 let (lower, _) = self.iter.size_hint();
50 (lower, None)
51 }
52 }
53
54 impl<I: Iterator<Item = char> + Clone> fmt::Display for Replacements<I> {
fmt(&self, f: &mut fmt::Formatter) -> fmt::Result55 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
56 for c in self.clone() {
57 f.write_char(c)?;
58 }
59 Ok(())
60 }
61 }
62