logo
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

// Copyright 2019 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.

//! Lookups of unicode properties using minimal perfect hashing.

use crate::perfect_hash::mph_lookup;
use crate::tables::*;

/// Look up the canonical combining class for a codepoint.
///
/// The value returned is as defined in the Unicode Character Database.
pub fn canonical_combining_class(c: char) -> u8 {
    mph_lookup(
        c.into(),
        CANONICAL_COMBINING_CLASS_SALT,
        CANONICAL_COMBINING_CLASS_KV,
        u8_lookup_fk,
        u8_lookup_fv,
        0,
    )
}

pub(crate) fn composition_table(c1: char, c2: char) -> Option<char> {
    if c1 < '\u{10000}' && c2 < '\u{10000}' {
        mph_lookup(
            (c1 as u32) << 16 | (c2 as u32),
            COMPOSITION_TABLE_SALT,
            COMPOSITION_TABLE_KV,
            pair_lookup_fk,
            pair_lookup_fv_opt,
            None,
        )
    } else {
        composition_table_astral(c1, c2)
    }
}

pub(crate) fn canonical_fully_decomposed(c: char) -> Option<&'static [char]> {
    mph_lookup(
        c.into(),
        CANONICAL_DECOMPOSED_SALT,
        CANONICAL_DECOMPOSED_KV,
        pair_lookup_fk,
        pair_lookup_fv_opt,
        None,
    )
    .map(|(start, len)| &CANONICAL_DECOMPOSED_CHARS[start as usize..][..len as usize])
}

pub(crate) fn compatibility_fully_decomposed(c: char) -> Option<&'static [char]> {
    mph_lookup(
        c.into(),
        COMPATIBILITY_DECOMPOSED_SALT,
        COMPATIBILITY_DECOMPOSED_KV,
        pair_lookup_fk,
        pair_lookup_fv_opt,
        None,
    )
    .map(|(start, len)| &COMPATIBILITY_DECOMPOSED_CHARS[start as usize..][..len as usize])
}

pub(crate) fn cjk_compat_variants_fully_decomposed(c: char) -> Option<&'static [char]> {
    mph_lookup(
        c.into(),
        CJK_COMPAT_VARIANTS_DECOMPOSED_SALT,
        CJK_COMPAT_VARIANTS_DECOMPOSED_KV,
        pair_lookup_fk,
        pair_lookup_fv_opt,
        None,
    )
    .map(|(start, len)| &CJK_COMPAT_VARIANTS_DECOMPOSED_CHARS[start as usize..][..len as usize])
}

/// Return whether the given character is a combining mark (`General_Category=Mark`)
pub fn is_combining_mark(c: char) -> bool {
    mph_lookup(
        c.into(),
        COMBINING_MARK_SALT,
        COMBINING_MARK_KV,
        bool_lookup_fk,
        bool_lookup_fv,
        false,
    )
}

pub fn stream_safe_trailing_nonstarters(c: char) -> usize {
    mph_lookup(
        c.into(),
        TRAILING_NONSTARTERS_SALT,
        TRAILING_NONSTARTERS_KV,
        u8_lookup_fk,
        u8_lookup_fv,
        0,
    ) as usize
}

/// Extract the key in a 24 bit key and 8 bit value packed in a u32.
#[inline]
fn u8_lookup_fk(kv: u32) -> u32 {
    kv >> 8
}

/// Extract the value in a 24 bit key and 8 bit value packed in a u32.
#[inline]
fn u8_lookup_fv(kv: u32) -> u8 {
    (kv & 0xff) as u8
}

/// Extract the key for a boolean lookup.
#[inline]
fn bool_lookup_fk(kv: u32) -> u32 {
    kv
}

/// Extract the value for a boolean lookup.
#[inline]
fn bool_lookup_fv(_kv: u32) -> bool {
    true
}

/// Extract the key in a pair.
#[inline]
fn pair_lookup_fk<T>(kv: (u32, T)) -> u32 {
    kv.0
}

/// Extract the value in a pair, returning an option.
#[inline]
fn pair_lookup_fv_opt<T>(kv: (u32, T)) -> Option<T> {
    Some(kv.1)
}