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/* Line breaking (UAX #14, Unicode 16.0): text/text.h. Each boundary is
* decided by the first rule, in the standard's order, that matches it; the
* rules that look back over spaces, marks or numbers read what a pass
* before them worked out for every position. */
#include "text.h"
#include <stdlib.h>
enum { BK = VEGA_LB_BK, CR = VEGA_LB_CR, LF = VEGA_LB_LF, NL = VEGA_LB_NL, SP = VEGA_LB_SP, ZW = VEGA_LB_ZW,
ZWJ = VEGA_LB_ZWJ, CM = VEGA_LB_CM, WJ = VEGA_LB_WJ, GL = VEGA_LB_GL, BA = VEGA_LB_BA, BB = VEGA_LB_BB,
B2 = VEGA_LB_B2, HY = VEGA_LB_HY, CB = VEGA_LB_CB, CL = VEGA_LB_CL, CP = VEGA_LB_CP, EX = VEGA_LB_EX,
IN = VEGA_LB_IN, NS = VEGA_LB_NS, OP = VEGA_LB_OP, QU = VEGA_LB_QU, IS = VEGA_LB_IS, NU = VEGA_LB_NU,
PO = VEGA_LB_PO, PR = VEGA_LB_PR, SY = VEGA_LB_SY, AK = VEGA_LB_AK, AL = VEGA_LB_AL, AP = VEGA_LB_AP,
AS = VEGA_LB_AS, EB = VEGA_LB_EB, EM = VEGA_LB_EM, H2 = VEGA_LB_H2, H3 = VEGA_LB_H3, HL = VEGA_LB_HL,
ID = VEGA_LB_ID, JL = VEGA_LB_JL, JV = VEGA_LB_JV, JT = VEGA_LB_JT, RI = VEGA_LB_RI, VF = VEGA_LB_VF,
VI = VEGA_LB_VI };
enum { NONE = VEGA_BREAK_NONE, ALLOWED = VEGA_BREAK_ALLOWED, MANDATORY = VEGA_BREAK_MANDATORY };
#define NO_UNIT SIZE_MAX
/* LB1: ambiguous, surrogate and unknown are alphabetic; complex context is
* a mark if it is one, else alphabetic; conditional Japanese starters are
* nonstarters. */
static uint8_t resolve(uint32_t code) {
VegaLineBreak c = vega_line_break(code);
switch (c) {
case VEGA_LB_AI: case VEGA_LB_SG: case VEGA_LB_XX: return AL;
case VEGA_LB_SA: {
VegaCategory g = vega_category(code);
return g == VEGA_MN || g == VEGA_MC ? CM : AL;
}
case VEGA_LB_CJ: return NS;
default: return (uint8_t)c;
}
}
typedef struct {
const uint32_t *codes;
size_t count;
uint8_t *cls; /* each character's class (LB1) */
uint8_t *eff; /* its unit's class: a mark takes its base's (LB9), a mark with none is alphabetic (LB10) */
uint8_t *joined; /* a mark that LB9 joins to the character before */
uint8_t *number; /* its unit ends NU (NU | SY | IS)* */
size_t *start; /* where its unit starts */
size_t *nonspace; /* where the last unit up to it that is not a space starts, or NO_UNIT */
size_t *ri; /* how many regional indicators end at its unit */
} Text;
static bool one_of(unsigned c, unsigned a, unsigned b) { return c == a || c == b; }
/* The unit after the one at i, or count. */
static size_t next_unit(const Text *t, size_t i) {
size_t j = i + 1;
while (j < t->count && t->joined[j]) j++;
return j;
}
static bool aksara_start(const Text *t, size_t unit) {
unsigned c = t->eff[unit];
return c == AK || c == AS || t->codes[unit] == 0x25CC;
}
static uint8_t decide(const Text *t, size_t i) {
unsigned a = t->cls[i - 1], b = t->cls[i], A = t->eff[i - 1], B = t->eff[i];
size_t unit = t->start[i - 1], before = t->nonspace[i - 1];
uint32_t base = t->codes[unit];
if (a == BK) return MANDATORY; /* LB4 */
if (a == CR && b == LF) return NONE; /* LB5 */
if (a == CR || a == LF || a == NL) return MANDATORY;
if (b == BK || b == CR || b == LF || b == NL) return NONE; /* LB6 */
if (b == SP || b == ZW) return NONE; /* LB7 */
if (before != NO_UNIT && t->eff[before] == ZW) return ALLOWED; /* LB8: ZW SP* ÷ */
if (a == ZWJ) return NONE; /* LB8a */
if (t->joined[i]) return NONE; /* LB9 */
if (A == WJ || B == WJ) return NONE; /* LB11 */
if (A == GL) return NONE; /* LB12 */
if (B == GL && A != SP && A != BA && A != HY) return NONE; /* LB12a */
if (B == CL || B == CP || B == EX || B == SY) return NONE; /* LB13 */
if (before != NO_UNIT && t->eff[before] == OP) return NONE; /* LB14: OP SP* × */
/* LB15a: an initial quotation mark after a start, opening or space,
* then spaces, and no break */
if (before != NO_UNIT && t->eff[before] == QU && vega_category(t->codes[before]) == VEGA_PI) {
if (!before) return NONE;
unsigned q = t->eff[before - 1];
if (q == BK || q == CR || q == LF || q == NL || q == OP || q == QU || q == GL || q == SP || q == ZW) return NONE;
}
/* LB15b: no break before a final quotation mark that ends something */
if (B == QU && vega_category(t->codes[i]) == VEGA_PF) {
size_t j = next_unit(t, i);
if (j == t->count) return NONE;
unsigned n = t->eff[j];
if (n == SP || n == GL || n == WJ || n == CL || n == QU || n == CP || n == EX || n == IS || n == SY ||
n == BK || n == CR || n == LF || n == NL || n == ZW)
return NONE;
}
/* LB15c: a decimal mark after a space, as in 'subtract .5'; LB15d:
* otherwise none before ';', ',' or '.' */
if (A == SP && B == IS) {
size_t j = next_unit(t, i);
if (j < t->count && t->eff[j] == NU) return ALLOWED;
}
if (B == IS) return NONE;
if (B == NS && before != NO_UNIT && one_of(t->eff[before], CL, CP)) return NONE; /* LB16 */
if (B == B2 && before != NO_UNIT && t->eff[before] == B2) return NONE; /* LB17 */
if (A == SP) return ALLOWED; /* LB18 */
/* LB19: none before a quotation mark but an initial one, nor after one
* but a final one; LB19a: nor either side of any unless East Asian
* characters are there */
if (B == QU && vega_category(t->codes[i]) != VEGA_PI) return NONE;
if (A == QU && vega_category(base) != VEGA_PF) return NONE;
if (B == QU) {
size_t j = next_unit(t, i);
if (!vega_east_asian(base) || j == t->count || !vega_east_asian(t->codes[j])) return NONE;
}
if (A == QU && (!vega_east_asian(t->codes[i]) || !unit || !vega_east_asian(t->codes[t->start[unit - 1]]))) return NONE;
if (B == CB || A == CB) return ALLOWED; /* LB20 */
/* LB20a: none after a word-initial hyphen */
if ((A == HY || base == 0x2010) && B == AL) {
unsigned w = unit ? t->eff[unit - 1] : SP;
if (w == BK || w == CR || w == LF || w == NL || w == SP || w == ZW || w == CB || w == GL) return NONE;
}
if (B == BA || B == HY || B == NS || A == BB) return NONE; /* LB21 */
/* LB21a: none after the hyphen in Hebrew + hyphen + non-Hebrew */
if ((A == HY || (A == BA && !vega_east_asian(base))) && unit && t->eff[unit - 1] == HL && B != HL) return NONE;
if (A == SY && B == HL) return NONE; /* LB21b */
if (B == IN) return NONE; /* LB22 */
if (one_of(A, AL, HL) && B == NU) return NONE; /* LB23 */
if (A == NU && one_of(B, AL, HL)) return NONE;
if (A == PR && (B == ID || B == EB || B == EM)) return NONE; /* LB23a */
if ((A == ID || A == EB || A == EM) && B == PO) return NONE;
if (one_of(A, PR, PO) && one_of(B, AL, HL)) return NONE; /* LB24 */
if (one_of(A, AL, HL) && one_of(B, PR, PO)) return NONE;
/* LB25: numbers (the rules before it keep ',', '.', '/' and closing
* punctuation to what they follow) */
if (one_of(B, PO, PR) && (t->number[i - 1] || (one_of(A, CL, CP) && unit && t->number[unit - 1]))) return NONE;
if (one_of(A, PO, PR)) {
if (B == NU) return NONE;
if (B == OP) { /* OP NU, OP IS NU */
size_t j = next_unit(t, i);
if (j < t->count && t->eff[j] == IS) j = next_unit(t, j);
if (j < t->count && t->eff[j] == NU) return NONE;
}
}
if (one_of(A, HY, IS) && B == NU) return NONE;
if (t->number[i - 1] && B == NU) return NONE;
if (A == JL && (B == JL || B == JV || B == H2 || B == H3)) return NONE; /* LB26 */
if (one_of(A, JV, H2) && one_of(B, JV, JT)) return NONE;
if (one_of(A, JT, H3) && B == JT) return NONE;
if ((A == JL || A == JV || A == JT || A == H2 || A == H3) && B == PO) return NONE; /* LB27 */
if (A == PR && (B == JL || B == JV || B == JT || B == H2 || B == H3)) return NONE;
if (one_of(A, AL, HL) && one_of(B, AL, HL)) return NONE; /* LB28 */
/* LB28a: aksaras of Brahmic scripts hold together */
bool a_start = aksara_start(t, unit), b_start = aksara_start(t, i);
if (A == AP && b_start) return NONE;
if (a_start && one_of(B, VF, VI)) return NONE;
if (A == VI && unit && aksara_start(t, t->start[unit - 1]) && (B == AK || t->codes[i] == 0x25CC)) return NONE;
if (a_start && b_start) {
size_t j = next_unit(t, i);
if (j < t->count && t->eff[j] == VF) return NONE;
}
if (A == IS && one_of(B, AL, HL)) return NONE; /* LB29 */
if ((A == AL || A == HL || A == NU) && B == OP && !vega_east_asian(t->codes[i])) return NONE; /* LB30 */
if (A == CP && !vega_east_asian(base) && (B == AL || B == HL || B == NU)) return NONE;
if (A == RI && B == RI && t->ri[i - 1] % 2) return NONE; /* LB30a */
if (B == EM && (A == EB || (vega_extended_pictographic(base) && vega_category(base) == VEGA_CN))) return NONE; /* LB30b */
return ALLOWED; /* LB31 */
}
bool vega_line_breaks(const uint32_t *codes, size_t count, uint8_t *breaks) {
breaks[0] = NONE; /* LB2 */
if (!count) return true;
uint8_t *bytes = malloc(count * 4);
size_t *sizes = malloc(count * 3 * sizeof(size_t));
if (!bytes || !sizes) {
free(bytes);
free(sizes);
return false;
}
Text t = {codes, count, bytes, bytes + count, bytes + 2 * count, bytes + 3 * count, sizes, sizes + count, sizes + 2 * count};
for (size_t i = 0; i < count; ++i) {
unsigned c = t.cls[i] = resolve(codes[i]);
bool mark = c == CM || c == ZWJ;
unsigned previous = i ? t.eff[i - 1] : SP;
/* LB9: a mark joins any unit but these; LB10: one that does not is alphabetic. */
t.joined[i] = mark && i && previous != BK && previous != CR && previous != LF && previous != NL &&
previous != SP && previous != ZW;
t.eff[i] = t.joined[i] ? (uint8_t)previous : mark ? AL : (uint8_t)c;
t.start[i] = t.joined[i] ? t.start[i - 1] : i;
t.nonspace[i] = t.eff[i] != SP ? t.start[i] : i ? t.nonspace[i - 1] : NO_UNIT;
unsigned e = t.eff[i];
t.number[i] = t.joined[i] ? t.number[i - 1] : e == NU || ((e == SY || e == IS) && i && t.number[i - 1]);
t.ri[i] = t.joined[i] ? t.ri[i - 1] : e == RI ? (i ? t.ri[i - 1] : 0) + 1 : 0;
}
for (size_t i = 1; i < count; ++i) breaks[i] = decide(&t, i);
breaks[count] = MANDATORY; /* LB3 */
free(bytes);
free(sizes);
return true;
}
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