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/* Line breaking of UTF-16 strings.
Copyright (C) 2001-2003, 2006-2022 Free Software Foundation, Inc.
Written by Bruno Haible <bruno@clisp.org>, 2001.
This file is free software.
It is dual-licensed under "the GNU LGPLv3+ or the GNU GPLv2+".
You can redistribute it and/or modify it under either
- the terms of the GNU Lesser General Public License as published
by the Free Software Foundation; either version 3, or (at your
option) any later version, or
- the terms of the GNU General Public License as published by the
Free Software Foundation; either version 2, or (at your option)
any later version, or
- the same dual license "the GNU LGPLv3+ or the GNU GPLv2+".
This file is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License and the GNU General Public License
for more details.
You should have received a copy of the GNU Lesser General Public
License and of the GNU General Public License along with this
program. If not, see <https://www.gnu.org/licenses/>. */
#include <config.h>
/* Specification. */
#include "unilbrk.h"
#include "unilbrk/internal.h"
#include <stdlib.h>
#include <string.h>
#include "unilbrk/lbrktables.h"
#include "uniwidth/cjk.h"
#include "unistr.h"
/* This file implements
Unicode Standard Annex #14 <https://www.unicode.org/reports/tr14/>. */
void
u16_possible_linebreaks_loop (const uint16_t *s, size_t n, const char *encoding,
int cr, char *p)
{
if (n > 0)
{
int LBP_AI_REPLACEMENT = (is_cjk_encoding (encoding) ? LBP_ID1 : LBP_AL);
const uint16_t *s_end = s + n;
int prev_prop = LBP_BK; /* line break property of last character */
int last_prop = LBP_BK; /* line break property of last non-space character */
char *seen_space = NULL; /* Was a space seen after the last non-space character? */
/* Don't break inside multibyte characters. */
memset (p, UC_BREAK_PROHIBITED, n);
/* Number of consecutive regional indicator (RI) characters seen
immediately before the current point. */
size_t ri_count = 0;
do
{
ucs4_t uc;
int count = u16_mbtouc_unsafe (&uc, s, s_end - s);
int prop = unilbrkprop_lookup (uc);
if (prop == LBP_BK || prop == LBP_LF || prop == LBP_CR)
{
/* (LB4,LB5,LB6) Mandatory break. */
*p = UC_BREAK_MANDATORY;
/* cr is either LBP_CR or -1. In the first case, recognize
a CR-LF sequence. */
if (prev_prop == cr && prop == LBP_LF)
p[-1] = UC_BREAK_CR_BEFORE_LF;
prev_prop = prop;
last_prop = LBP_BK;
seen_space = NULL;
}
else
{
/* Resolve property values whose behaviour is not fixed. */
switch (prop)
{
case LBP_AI:
/* Resolve ambiguous. */
prop = LBP_AI_REPLACEMENT;
break;
case LBP_CB:
/* This is arbitrary. */
prop = LBP_ID1;
break;
case LBP_SA:
/* We don't handle complex scripts yet.
Treat LBP_SA like LBP_XX. */
case LBP_XX:
/* This is arbitrary. */
prop = LBP_AL;
break;
}
/* Deal with spaces and combining characters. */
if (prop == LBP_SP)
{
/* (LB7) Don't break just before a space. */
*p = UC_BREAK_PROHIBITED;
seen_space = p;
}
else if (prop == LBP_ZW)
{
/* (LB7) Don't break just before a zero-width space. */
*p = UC_BREAK_PROHIBITED;
last_prop = LBP_ZW;
seen_space = NULL;
}
else if (prop == LBP_CM || prop == LBP_ZWJ)
{
/* (LB9) Don't break just before a combining character or
zero-width joiner, except immediately after a mandatory
break character, space, or zero-width space. */
if (last_prop == LBP_BK)
{
/* (LB4,LB5,LB6) Don't break at the beginning of a line. */
*p = UC_BREAK_PROHIBITED;
/* (LB10) Treat CM or ZWJ as AL. */
last_prop = LBP_AL;
seen_space = NULL;
}
else if (last_prop == LBP_ZW || seen_space != NULL)
{
/* (LB8) Break after zero-width space. */
/* (LB18) Break after spaces.
We do *not* implement the "legacy support for space
character as base for combining marks" because now the
NBSP CM sequence is recommended instead of SP CM. */
*p = UC_BREAK_POSSIBLE;
/* (LB10) Treat CM or ZWJ as AL. */
last_prop = LBP_AL;
seen_space = NULL;
}
else
{
/* Treat X CM as if it were X. */
*p = UC_BREAK_PROHIBITED;
}
}
else
{
/* prop must be usable as an index for table 7.3 of UTR #14. */
if (!(prop >= 0 && prop < sizeof (unilbrk_table) / sizeof (unilbrk_table[0])))
abort ();
if (last_prop == LBP_BK)
{
/* (LB4,LB5,LB6) Don't break at the beginning of a line. */
*p = UC_BREAK_PROHIBITED;
}
else if (last_prop == LBP_ZW)
{
/* (LB8) Break after zero-width space. */
*p = UC_BREAK_POSSIBLE;
}
else if (prev_prop == LBP_ZWJ)
{
/* (LB8a) Don't break right after a zero-width joiner. */
*p = UC_BREAK_PROHIBITED;
}
else if (last_prop == LBP_RI && prop == LBP_RI)
{
/* (LB30a) Break between two regional indicator symbols
if and only if there are an even number of regional
indicators preceding the position of the break. */
*p = (seen_space != NULL || (ri_count % 2) == 0
? UC_BREAK_POSSIBLE
: UC_BREAK_PROHIBITED);
}
else if (prev_prop == LBP_HL_BA)
{
/* (LB21a) Don't break after Hebrew + Hyphen/Break-After. */
*p = UC_BREAK_PROHIBITED;
}
else
{
switch (unilbrk_table [last_prop] [prop])
{
case D:
*p = UC_BREAK_POSSIBLE;
break;
case I:
*p = (seen_space != NULL ? UC_BREAK_POSSIBLE : UC_BREAK_PROHIBITED);
break;
case P:
*p = UC_BREAK_PROHIBITED;
break;
default:
abort ();
}
}
last_prop = prop;
seen_space = NULL;
}
prev_prop = (prev_prop == LBP_HL && (prop == LBP_HY || prop == LBP_BA)
? LBP_HL_BA
: prop);
}
if (prop == LBP_RI)
ri_count++;
else
ri_count = 0;
s += count;
p += count;
}
while (s < s_end);
}
}
#undef u16_possible_linebreaks
void
u16_possible_linebreaks (const uint16_t *s, size_t n, const char *encoding,
char *p)
{
u16_possible_linebreaks_loop (s, n, encoding, -1, p);
}
void
u16_possible_linebreaks_v2 (const uint16_t *s, size_t n, const char *encoding,
char *p)
{
u16_possible_linebreaks_loop (s, n, encoding, LBP_CR, p);
}
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