portal_calendar/Utf8Iterator.cpp at master · wuspy/portal_calendar · GitHub

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
#include "Utf8Iterator.h"

Utf8Iterator::Utf8Iterator(String str)
{
    _str = str;
    _pos = 0;
}

uint16_t Utf8Iterator::next()
{
    if (_pos >= _str.length()) {
        return 0;
    }

    uint8_t len = sequenceLength(_str[_pos]);
    uint16_t cp = _str[_pos];
    switch (len) {
        case 1:
            ++_pos;
            return cp;
        case 2:
            cp = ((cp << 6) & 0x7FF) + (_str[++_pos] & 0x3F);
            ++_pos;
            return cp;
        case 3:
            cp = ((cp << 12) & 0xFFFF) + ((_str[++_pos] << 6) & 0xFFF);
            cp += _str[++_pos] & 0x3F;
            ++_pos;
            return cp;
        case 4:
            // Code points over U+FFFF are not supported
            _pos += 4;
            return 0xFFFD;
        default:
            return 0;
    }
}

uint8_t Utf8Iterator::sequenceLength(uint8_t lead)
{
    if (lead < 0x80) {
        return 1;
    } else if ((lead >> 5) == 0x6) {
        return 2;
    } else if ((lead >> 4) == 0xE) {
        return 3;
    } else if ((lead >> 3) == 0x1E) {
        return 4;
    } else {
        return 0;
    }
}

bool Utf8Iterator::isSpaceCodePoint(uint16_t cp) {
    return cp == 0x9 || cp == 0x20 || cp == 0xA0;
};

bool Utf8Iterator::isNewlineCodePoint(uint16_t cp) {
    return cp == 0xA;
};