unic_utils/
tables.rs

1// Copyright 2017 The UNIC Project Developers.
2//
3// See the COPYRIGHT file at the top-level directory of this distribution.
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
11
12//! Character data tables used in UNIC.
13
14
15use unic_char_range::CharRange;
16
17/// A mapping from characters to some associated data.
18///
19/// For the set case, use `()` as the associated value.
20#[derive(Copy, Clone, Debug)]
21pub enum CharDataTable<V: 'static> {
22    #[doc(hidden)] Direct(&'static [(char, V)]),
23    #[doc(hidden)] Range(&'static [(CharRange, V)]),
24}
25
26impl<V> Default for CharDataTable<V> {
27    fn default() -> Self {
28        CharDataTable::Direct(&[])
29    }
30}
31
32impl<V> CharDataTable<V> {
33    /// Does this table contain a mapping for a character?
34    pub fn contains(&self, needle: char) -> bool {
35        match *self {
36            CharDataTable::Direct(table) => {
37                table.binary_search_by_key(&needle, |&(k, _)| k).is_ok()
38            }
39            CharDataTable::Range(table) => table
40                .binary_search_by(|&(range, _)| range.cmp(needle))
41                .is_ok(),
42        }
43    }
44}
45
46impl<V: Copy> CharDataTable<V> {
47    /// Find the associated data for a character in this table.
48    pub fn find(&self, needle: char) -> Option<V> {
49        match *self {
50            CharDataTable::Direct(table) => table
51                .binary_search_by_key(&needle, |&(k, _)| k)
52                .map(|idx| table[idx].1)
53                .ok(),
54            CharDataTable::Range(table) => table
55                .binary_search_by(|&(range, _)| range.cmp(needle))
56                .map(|idx| table[idx].1)
57                .ok(),
58        }
59    }
60}
61
62impl<V: Copy + Default> CharDataTable<V> {
63    /// Find the associated data for a character in this table, or the default value if not entered.
64    pub fn find_or_default(&self, needle: char) -> V {
65        self.find(needle).unwrap_or_else(Default::default)
66    }
67}
68
69/// Iterator for `CharDataTable`. Iterates over pairs `(CharRange, V)`.
70pub struct CharDataTableIter<'a, V: 'static>(&'a CharDataTable<V>, usize);
71
72impl<'a, V: Copy> Iterator for CharDataTableIter<'a, V> {
73    type Item = (CharRange, V);
74
75    fn next(&mut self) -> Option<Self::Item> {
76        match *self.0 {
77            CharDataTable::Direct(arr) => if self.1 >= arr.len() {
78                None
79            } else {
80                let idx = self.1;
81                self.1 += 1;
82                let (ch, v) = arr[idx];
83                Some((chars!(ch..=ch), v))
84            },
85            CharDataTable::Range(arr) => if self.1 >= arr.len() {
86                None
87            } else {
88                let idx = self.1;
89                self.1 += 1;
90                Some(arr[idx])
91            },
92        }
93    }
94}
95
96impl<V> CharDataTable<V> {
97    /// Iterate over the entries in this table. Yields pairs `(CharRange, V)`.
98    pub fn iter(&self) -> CharDataTableIter<V> {
99        CharDataTableIter(&self, 0)
100    }
101}
unic_utils/tables.rs

unic_utils/
tables.rs
