commit 94fb8dc7588eb4ee563f5a4c888fcd65a8497834
Author: Laslo Hunhold <[email protected]>
AuthorDate: Sat Oct 17 18:17:04 2020 +0200
Commit: Laslo Hunhold <[email protected]>
CommitDate: Sat Oct 17 18:17:04 2020 +0200
Refactor grapheme_boundary()
Get rid of the macro-mess, make the code more readable with better
comments and formatting and allow the state-pointer to be NULL, which
is as if the value state is pointing to contained 0, only with the
difference that the state is not updated.
I would, actually, prefer to return some kind of error, but I like
the fact that the function can't really error out as is, which is why
I've chosen this compromise.
Signed-off-by: Laslo Hunhold <[email protected]>
diff --git a/src/boundary_body.c b/src/boundary_body.c
index b86345b..3a41215 100644
--- a/src/boundary_body.c
+++ b/src/boundary_body.c
@@ -10,37 +10,27 @@ enum {
GRAPHEME_STATE_EMOJI = 1 << 1, /* within emoji modifier or zwj
sequence */
};
-static int
-cp_cmp(const void *a, const void *b)
-{
- uint32_t cp = *(uint32_t *)a;
- uint32_t *range = (uint32_t *)b;
-
- return (cp >= range[0] && cp <= range[1]) ? 0 : (cp - range[0]);
-}
-
-enum property {
- PROP_CR, /* carriage return */
- PROP_LF, /* line feed */
- PROP_CONTROL, /* control character */
- PROP_EXTEND, /* grapheme extender (TODO Emoji_Modifier=Yes) */
- PROP_ZWJ, /* zero width joiner */
- PROP_RI, /* regional indicator */
- PROP_PREPEND, /* prepend character */
- PROP_SPACINGMARK, /* spacing mark */
- PROP_L, /* hangul syllable type L */
- PROP_V, /* hangul syllable type V */
- PROP_T, /* hangul syllable type T */
- PROP_LV, /* hangul syllable type LV */
- PROP_LVT, /* hangul syllable type LVT */
- PROP_EXTPICT, /* extended pictographic */
- NUM_PROPS,
+enum cp_property {
+ PROP_CR, /* carriage return */
+ PROP_LF, /* line feed */
+ PROP_CONTROL, /* control character */
+ PROP_EXTEND, /* grapheme extender (TODO Emoji_Modifier=Yes) */
+ PROP_ZWJ, /* zero width joiner */
+ PROP_RI, /* regional indicator */
+ PROP_PREPEND, /* prepend character */
+ PROP_SPACINGMARK, /* spacing mark */
+ PROP_L, /* hangul syllable type L */
+ PROP_V, /* hangul syllable type V */
+ PROP_T, /* hangul syllable type T */
+ PROP_LV, /* hangul syllable type LV */
+ PROP_LVT, /* hangul syllable type LVT */
+ PROP_EXTPICT, /* extended pictographic */
};
struct {
const uint32_t (*table)[2];
size_t tablelen;
-} tables[] = {
+} cp_property_tables[] = {
[PROP_CR] = {
.table = cr_table,
.tablelen = LEN(cr_table),
@@ -99,128 +89,186 @@ struct {
},
};
+struct cp_properties {
+ uint32_t cp;
+ int_least16_t determined;
+ int_least16_t state;
+};
+
static int
-is(uint32_t cp[2], char (*props)[2], int index, enum property p)
+cp_cmp(const void *a, const void *b)
{
- if (props[p][index] == 2) {
- /* need to determine property */
- props[p][index] = (bsearch(&(cp[index]),
- tables[p].table,
- tables[p].tablelen,
- sizeof(*(tables[p].table)),
- cp_cmp) == NULL) ? 0 : 1;
- }
+ uint32_t cp = *(uint32_t *)a;
+ uint32_t *range = (uint32_t *)b;
- return props[p][index];
+ return (cp >= range[0] && cp <= range[1]) ? 0 : (cp - range[0]);
}
-#define IS(I, PROP) (is(cp, props, I, PROP))
+static int
+has_property(struct cp_properties *props, enum cp_property p)
+{
+ if (!(props->determined & (1 << p))) {
+ /* not determined yet, do a lookup and set the state */
+ if (bsearch(&props->cp, cp_property_tables[p].table,
+ cp_property_tables[p].tablelen,
+ sizeof(*cp_property_tables[p].table),
+ cp_cmp)) {
+ props->state |= (1 << p);
+ } else {
+ props->state &= ~(1 << p);
+ }
+
+ /* now it's determined */
+ props->determined |= (1 << p);
+ }
+
+ return (props->state & (1 << p));
+}
int
-grapheme_boundary(uint32_t cp0, uint32_t cp1, int *state)
+grapheme_boundary(uint32_t a, uint32_t b, int *state)
{
- uint32_t cp[2] = { cp0, cp1 };
- char props[NUM_PROPS][2];
- size_t i;
+ struct cp_properties props[] = {
+ {
+ .cp = a,
+ },
+ {
+ .cp = b,
+ },
+ };
+ int s;
- if ((cp0 >= 0x20 && cp0 <= 0x7E) &&
- (cp1 >= 0x20 && cp1 <= 0x7E)) {
- /* skip printable ascii */
+ /* skip printable ASCII */
+ if ((a >= 0x20 && a <= 0x7E) &&
+ (b >= 0x20 && b <= 0x7E)) {
return 1;
}
- /* set all properties to undetermined (2) */
- for (i = 0; i < NUM_PROPS; i++) {
- props[i][0] = props[i][1] = 2;
- }
+ /* set internal state based on given state-pointer */
+ s = (state != NULL) ? *state : 0;
- /* http://unicode.org/reports/tr29/#Grapheme_Cluster_Boundary_Rules */
+ /*
+ * Apply grapheme cluster breaking algorithm (UAX #29), see
+ * http://unicode.org/reports/tr29/#Grapheme_Cluster_Boundary_Rules
+ */
- /* update state machine */
- if (IS(1, PROP_RI)) {
- if (IS(0, PROP_RI)) {
+ /*
+ * update state
+ */
+ if (has_property(&props[1], PROP_RI)) {
+ if (has_property(&props[0], PROP_RI)) {
/* one more RI is on the left side of the seam */
- *state ^= GRAPHEME_STATE_RI_ODD;
+ s ^= GRAPHEME_STATE_RI_ODD;
} else {
/* an RI appeared on the right side but the left
side is not an RI, reset state (0 is even) */
- *state &= ~GRAPHEME_STATE_RI_ODD;
+ s &= ~GRAPHEME_STATE_RI_ODD;
}
}
if (!(*state & GRAPHEME_STATE_EMOJI) &&
- ((IS(0, PROP_EXTPICT) && IS(1, PROP_ZWJ)) ||
- (IS(0, PROP_EXTPICT) && IS(1, PROP_EXTEND)))) {
- *state |= GRAPHEME_STATE_EMOJI;
+ ((has_property(&props[0], PROP_EXTPICT) &&
+ has_property(&props[1], PROP_ZWJ)) ||
+ (has_property(&props[0], PROP_EXTPICT) &&
+ has_property(&props[1], PROP_EXTEND)))) {
+ s |= GRAPHEME_STATE_EMOJI;
} else if ((*state & GRAPHEME_STATE_EMOJI) &&
- (
- (IS(0, PROP_ZWJ) && IS(1, PROP_EXTPICT)) ||
- (IS(0, PROP_EXTEND) && IS(1, PROP_EXTEND)) ||
- (IS(0, PROP_EXTEND) && IS(1, PROP_ZWJ)) ||
- (IS(0, PROP_EXTPICT) && IS(1, PROP_ZWJ)) ||
- (IS(0, PROP_EXTPICT) && IS(1, PROP_EXTEND))
- )
- ) {
+ ((has_property(&props[0], PROP_ZWJ) &&
+ has_property(&props[1], PROP_EXTPICT)) ||
+ (has_property(&props[0], PROP_EXTEND) &&
+ has_property(&props[1], PROP_EXTEND)) ||
+ (has_property(&props[0], PROP_EXTEND) &&
+ has_property(&props[1], PROP_ZWJ)) ||
+ (has_property(&props[0], PROP_EXTPICT) &&
+ has_property(&props[1], PROP_ZWJ)) ||
+ (has_property(&props[0], PROP_EXTPICT) &&
+ has_property(&props[1], PROP_EXTEND)))) {
/* GRAPHEME_STATE_EMOJI remains */
} else {
- *state &= ~GRAPHEME_STATE_EMOJI;
+ s &= ~GRAPHEME_STATE_EMOJI;
}
+ /* write updated state to state-pointer, if given */
+ if (state != NULL) {
+ *state = s;
+ }
+
+ /*
+ * apply rules
+ */
+
+ /* skip GB1 and GB2, as they are never satisfied here */
+
/* GB3 */
- if (IS(0, PROP_CR) && IS(1, PROP_LF)) {
+ if (has_property(&props[0], PROP_CR) &&
+ has_property(&props[1], PROP_LF)) {
return 0;
}
/* GB4 */
- if (IS(0, PROP_CONTROL) || IS(0, PROP_CR) || IS(0, PROP_LF)) {
+ if (has_property(&props[0], PROP_CONTROL) ||
+ has_property(&props[0], PROP_CR) ||
+ has_property(&props[0], PROP_LF)) {
return 1;
}
/* GB5 */
- if (IS(1, PROP_CONTROL) || IS(1, PROP_CR) || IS(1, PROP_LF)) {
+ if (has_property(&props[1], PROP_CONTROL) ||
+ has_property(&props[1], PROP_CR) ||
+ has_property(&props[1], PROP_LF)) {
return 1;
}
/* GB6 */
- if (IS(0, PROP_L) && (IS(1, PROP_L) || IS(1, PROP_V) ||
- IS(1, PROP_LV) || IS(1, PROP_LVT))) {
+ if (has_property(&props[0], PROP_L) &&
+ (has_property(&props[1], PROP_L) ||
+ has_property(&props[1], PROP_V) ||
+ has_property(&props[1], PROP_LV) ||
+ has_property(&props[1], PROP_LVT))) {
return 0;
}
/* GB7 */
- if ((IS(0, PROP_LV) || IS(0, PROP_V)) && (IS(1, PROP_V) ||
- IS(1, PROP_T))) {
+ if ((has_property(&props[0], PROP_LV) ||
+ has_property(&props[0], PROP_V)) &&
+ (has_property(&props[1], PROP_V) ||
+ has_property(&props[1], PROP_T))) {
return 0;
}
/* GB8 */
- if ((IS(0, PROP_LVT) || IS(0, PROP_T)) && IS(1, PROP_T)) {
+ if ((has_property(&props[0], PROP_LVT) ||
+ has_property(&props[0], PROP_T)) &&
+ has_property(&props[1], PROP_T)) {
return 0;
}
/* GB9 */
- if (IS(1, PROP_EXTEND) || IS(1, PROP_ZWJ)) {
+ if (has_property(&props[1], PROP_EXTEND) ||
+ has_property(&props[1], PROP_ZWJ)) {
return 0;
}
/* GB9a */
- if (IS(1, PROP_SPACINGMARK)) {
+ if (has_property(&props[1], PROP_SPACINGMARK)) {
return 0;
}
/* GB9b */
- if (IS(0, PROP_PREPEND)) {
+ if (has_property(&props[0], PROP_PREPEND)) {
return 0;
}
/* GB11 */
- if ((*state & GRAPHEME_STATE_EMOJI) && IS(0, PROP_ZWJ) &&
- IS(1, PROP_EXTPICT)) {
+ if ((s & GRAPHEME_STATE_EMOJI) &&
+ has_property(&props[0], PROP_ZWJ) &&
+ has_property(&props[1], PROP_EXTPICT)) {
return 0;
}
/* GB12/GB13 */
- if (IS(0, PROP_RI) && IS(1, PROP_RI) &&
- (*state & GRAPHEME_STATE_RI_ODD)) {
+ if (has_property(&props[0], PROP_RI) &&
+ has_property(&props[1], PROP_RI) &&
+ (s & GRAPHEME_STATE_RI_ODD)) {
return 0;
}
