1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
|
// Copyright 2012-2015 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.
//! Functions for computing canonical and compatible decompositions for Unicode characters.
use std::cmp::Ordering::{Equal, Less, Greater};
use std::ops::FnMut;
use tables::normalization::{canonical_table, compatibility_table, composition_table};
fn bsearch_table<T>(c: char, r: &'static [(char, &'static [T])]) -> Option<&'static [T]> {
match r.binary_search_by(|&(val, _)| {
if c == val { Equal }
else if val < c { Less }
else { Greater }
}) {
Ok(idx) => {
let (_, result) = r[idx];
Some(result)
}
Err(_) => None
}
}
/// Compute canonical Unicode decomposition for character.
/// See [Unicode Standard Annex #15](http://www.unicode.org/reports/tr15/)
/// for more information.
pub fn decompose_canonical<F>(c: char, mut i: F) where F: FnMut(char) { d(c, &mut i, false); }
/// Compute canonical or compatible Unicode decomposition for character.
/// See [Unicode Standard Annex #15](http://www.unicode.org/reports/tr15/)
/// for more information.
pub fn decompose_compatible<F>(c: char, mut i: F) where F: FnMut(char) { d(c, &mut i, true); }
// FIXME(#19596) This is a workaround, we should use `F` instead of `&mut F`
fn d<F>(c: char, i: &mut F, k: bool) where F: FnMut(char) {
// 7-bit ASCII never decomposes
if c <= '\x7f' { (*i)(c); return; }
// Perform decomposition for Hangul
if (c as u32) >= S_BASE && (c as u32) < (S_BASE + S_COUNT) {
decompose_hangul(c, i);
return;
}
// First check the canonical decompositions
match bsearch_table(c, canonical_table) {
Some(canon) => {
for x in canon {
d(*x, i, k);
}
return;
}
None => ()
}
// Bottom out if we're not doing compat.
if !k { (*i)(c); return; }
// Then check the compatibility decompositions
match bsearch_table(c, compatibility_table) {
Some(compat) => {
for x in compat {
d(*x, i, k);
}
return;
}
None => ()
}
// Finally bottom out.
(*i)(c);
}
/// Compose two characters into a single character, if possible.
/// See [Unicode Standard Annex #15](http://www.unicode.org/reports/tr15/)
/// for more information.
pub fn compose(a: char, b: char) -> Option<char> {
compose_hangul(a, b).or_else(|| {
match bsearch_table(a, composition_table) {
None => None,
Some(candidates) => {
match candidates.binary_search_by(|&(val, _)| {
if b == val { Equal }
else if val < b { Less }
else { Greater }
}) {
Ok(idx) => {
let (_, result) = candidates[idx];
Some(result)
}
Err(_) => None
}
}
}
})
}
// Constants from Unicode 7.0.0 Section 3.12 Conjoining Jamo Behavior
const S_BASE: u32 = 0xAC00;
const L_BASE: u32 = 0x1100;
const V_BASE: u32 = 0x1161;
const T_BASE: u32 = 0x11A7;
const L_COUNT: u32 = 19;
const V_COUNT: u32 = 21;
const T_COUNT: u32 = 28;
const N_COUNT: u32 = (V_COUNT * T_COUNT);
const S_COUNT: u32 = (L_COUNT * N_COUNT);
// FIXME(#19596) This is a workaround, we should use `F` instead of `&mut F`
// Decompose a precomposed Hangul syllable
#[allow(unsafe_code)]
#[inline(always)]
fn decompose_hangul<F>(s: char, f: &mut F) where F: FnMut(char) {
use std::mem::transmute;
let si = s as u32 - S_BASE;
let li = si / N_COUNT;
unsafe {
(*f)(transmute(L_BASE + li));
let vi = (si % N_COUNT) / T_COUNT;
(*f)(transmute(V_BASE + vi));
let ti = si % T_COUNT;
if ti > 0 {
(*f)(transmute(T_BASE + ti));
}
}
}
// Compose a pair of Hangul Jamo
#[allow(unsafe_code)]
#[inline(always)]
fn compose_hangul(a: char, b: char) -> Option<char> {
use std::mem::transmute;
let l = a as u32;
let v = b as u32;
// Compose an LPart and a VPart
if L_BASE <= l && l < (L_BASE + L_COUNT) && V_BASE <= v && v < (V_BASE + V_COUNT) {
let r = S_BASE + (l - L_BASE) * N_COUNT + (v - V_BASE) * T_COUNT;
return unsafe { Some(transmute(r)) };
}
// Compose an LVPart and a TPart
if S_BASE <= l && l <= (S_BASE+S_COUNT-T_COUNT) && T_BASE <= v && v < (T_BASE+T_COUNT) {
let r = l + (v - T_BASE);
return unsafe { Some(transmute(r)) };
}
None
}
|
