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authorAndreas Rottmann <a.rottmann@gmx.at>2009-09-14 12:32:44 +0200
committerAndreas Rottmann <a.rottmann@gmx.at>2009-09-14 12:32:44 +0200
commitfa095a4504cbe668e4244547e2c141597bea4ecf (patch)
tree06135820a286ffec47804e75fbf8a147e92acd2e /lib/unilbrk/u16-possible-linebreaks.c
Imported Upstream version 0.9.1upstream/0.9.1
Diffstat (limited to 'lib/unilbrk/u16-possible-linebreaks.c')
-rw-r--r--lib/unilbrk/u16-possible-linebreaks.c164
1 files changed, 164 insertions, 0 deletions
diff --git a/lib/unilbrk/u16-possible-linebreaks.c b/lib/unilbrk/u16-possible-linebreaks.c
new file mode 100644
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+++ b/lib/unilbrk/u16-possible-linebreaks.c
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+/* Line breaking of UTF-16 strings.
+ Copyright (C) 2001-2003, 2006-2009 Free Software Foundation, Inc.
+ Written by Bruno Haible <bruno@clisp.org>, 2001.
+
+ This program is free software: you can redistribute it and/or modify it
+ under the terms of the GNU Lesser General Public License as published
+ by the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program 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 for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+#include <config.h>
+
+/* Specification. */
+#include "unilbrk.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+#include "unilbrk/lbrktables.h"
+#include "uniwidth/cjk.h"
+#include "unistr.h"
+
+void
+u16_possible_linebreaks (const uint16_t *s, size_t n, const char *encoding, char *p)
+{
+ int LBP_AI_REPLACEMENT = (is_cjk_encoding (encoding) ? LBP_ID : LBP_AL);
+ const uint16_t *s_end = s + n;
+ 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? */
+ char *seen_space2 = NULL; /* At least two spaces after the last non-space? */
+
+ /* Don't break inside multibyte characters. */
+ memset (p, UC_BREAK_PROHIBITED, n);
+
+ while (s < s_end)
+ {
+ ucs4_t uc;
+ int count = u16_mbtouc_unsafe (&uc, s, s_end - s);
+ int prop = unilbrkprop_lookup (uc);
+
+ if (prop == LBP_BK)
+ {
+ /* Mandatory break. */
+ *p = UC_BREAK_MANDATORY;
+ last_prop = LBP_BK;
+ seen_space = NULL;
+ seen_space2 = NULL;
+ }
+ else
+ {
+ char *q;
+
+ /* 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_ID;
+ 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. */
+ q = p;
+ if (prop == LBP_SP)
+ {
+ /* Don't break just before a space. */
+ *p = UC_BREAK_PROHIBITED;
+ seen_space2 = seen_space;
+ seen_space = p;
+ }
+ else if (prop == LBP_ZW)
+ {
+ /* Don't break just before a zero-width space. */
+ *p = UC_BREAK_PROHIBITED;
+ last_prop = LBP_ZW;
+ seen_space = NULL;
+ seen_space2 = NULL;
+ }
+ else if (prop == LBP_CM)
+ {
+ /* Don't break just before a combining character, except immediately after a
+ zero-width space. */
+ if (last_prop == LBP_ZW)
+ {
+ /* Break after zero-width space. */
+ *p = UC_BREAK_POSSIBLE;
+ /* A combining character turns a preceding space into LBP_ID. */
+ last_prop = LBP_ID;
+ }
+ else
+ {
+ *p = UC_BREAK_PROHIBITED;
+ /* A combining character turns a preceding space into LBP_ID. */
+ if (seen_space != NULL)
+ {
+ q = seen_space;
+ seen_space = seen_space2;
+ prop = LBP_ID;
+ goto lookup_via_table;
+ }
+ }
+ }
+ else
+ {
+ lookup_via_table:
+ /* 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)
+ {
+ /* Don't break at the beginning of a line. */
+ *q = UC_BREAK_PROHIBITED;
+ }
+ else if (last_prop == LBP_ZW)
+ {
+ /* Break after zero-width space. */
+ *q = UC_BREAK_POSSIBLE;
+ }
+ else
+ {
+ switch (unilbrk_table [last_prop] [prop])
+ {
+ case D:
+ *q = UC_BREAK_POSSIBLE;
+ break;
+ case I:
+ *q = (seen_space != NULL ? UC_BREAK_POSSIBLE : UC_BREAK_PROHIBITED);
+ break;
+ case P:
+ *q = UC_BREAK_PROHIBITED;
+ break;
+ default:
+ abort ();
+ }
+ }
+ last_prop = prop;
+ seen_space = NULL;
+ seen_space2 = NULL;
+ }
+ }
+
+ s += count;
+ p += count;
+ }
+}