aboutsummaryrefslogtreecommitdiff
path: root/lib/unicode/gbrk/u8gnext.c
blob: f3f7afc369dd71617fcd0818392f9c1671dcbe7d (plain) (blame)
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
#include <stddef.h>

#include "__bsearch.h"
#include "mbstring.h"
#include "unicode/__gbrk.h"
#include "unicode/gbrk.h"

struct gbrk_state {
	enum {
		GB9C_NONE,
		GB9C_CNSNT,
		GB9C_LNK,
	} gb9c;
	bool gb11 : 1;
	bool gb12 : 1;
};

static bool u8isgbrk(rune, rune, struct gbrk_state *);

__MLIB_DEFINE_BSEARCH(gbrk_prop, gbrk_prop_tbl, GBP_OTHER)

size_t
u8gnext(struct u8view *g, const char8_t **s, size_t *n)
{
	int m;
	rune ch1;
	const char8_t *p;
	struct gbrk_state gs = {0};

	if (*n == 0)
		return 0;

	p = *s;
	if (g)
		g->p = p;
	p += u8tor(&ch1, p);

	for (;;) {
		rune ch2;

		if ((size_t)(p - *s) >= *n)
			ch2 = 0;
		else
			m = u8tor(&ch2, p);
		if (u8isgbrk(ch1, ch2, &gs)) {
			ptrdiff_t d = p - *s;
			*n -= d;
			*s = p;
			if (g)
				g->len = d;
			return d;
		}

		ch1 = ch2;
		p += m;
	}
}

bool
u8isgbrk(rune a, rune b, struct gbrk_state *gs)
{
	gbrk_prop ap, bp;

	/* GB1 & GB2 */
	if (!a || !b)
		goto do_break;

	/* GB3 & ASCII fast-track */
	if ((a | b) < 0x300) {
		if (a == '\r' && b == '\n')
			return false;
		goto do_break;
	}

	/* GB4 */
	if (a == '\r' || a == '\n' || ((ap = mlib_lookup(a)) & GBP_CTRL))
		goto do_break;

	/* GB5 */
	if (b == '\r' || b == '\n' || ((bp = mlib_lookup(b)) & GBP_CTRL))
		goto do_break;

	/* Setting flags for GB9c */
	if (ap & GBP_INDC_CNSNT)
		gs->gb9c = GB9C_CNSNT;
	else if ((ap & GBP_INDC_LNK) && gs->gb9c == GB9C_CNSNT)
		gs->gb9c = GB9C_LNK;

	/* GB6 */
	if ((ap & GBP_HNGL_L)
	    && (bp & (GBP_HNGL_L | GBP_HNGL_V | GBP_HNGL_LV | GBP_HNGL_LVT)))
	{
		return false;
	}

	/* GB7 */
	if ((ap & (GBP_HNGL_LV | GBP_HNGL_V)) && (bp & (GBP_HNGL_V | GBP_HNGL_T)))
		return false;

	/* GB8 */
	if ((ap & (GBP_HNGL_LVT | GBP_HNGL_T)) && (bp & GBP_HNGL_T))
		return false;

	/* GB9 */
	if (bp & (GBP_EXT | GBP_ZWJ)) {
		if (ap & GBP_PIC)
			gs->gb11 = true;
		return false;
	}

	/* GB9a */
	if (bp & GBP_SM)
		return false;

	/* GB9b */
	if (ap & GBP_PREP)
		return false;

	/* GB9c */
	if ((ap & (GBP_INDC_EXT | GBP_INDC_LNK)) && (bp & GBP_INDC_CNSNT)
	    && gs->gb9c == GB9C_LNK)
	{
		return false;
	}

	/* GB11 */
	if (gs->gb11) {
		if ((ap & GBP_EXT) && (bp & (GBP_EXT | GBP_ZWJ)))
			return false;
		if ((ap & GBP_ZWJ) && (bp & GBP_PIC))
			return false;
	}

	/* GB12 & GB13 */
	if (ap & GBP_RI) {
		if (gs->gb12 || !(bp & GBP_RI))
			goto do_break;
		gs->gb12 = true;
		return false;
	}

	/* GB999 */
do_break:
	gs->gb9c = GB9C_NONE;
	gs->gb11 = gs->gb12 = false;
	return true;
}