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authorManuel A. Fernandez Montecelo <manuel.montezelo@gmail.com>2016-05-26 16:48:15 +0100
committerManuel A. Fernandez Montecelo <manuel.montezelo@gmail.com>2016-05-26 16:48:15 +0100
commit5f2b09982312c98863eb9a8dfe2c608b81f58259 (patch)
treee5d38581c2f36e1cca02efedd2d85044d77f76f9 /lib/unigbrk/ulc-grapheme-breaks.c
parent3e0814cd9862b89c7a39672672937477bd87ddfb (diff)
Imported Upstream version 0.9.6upstream/0.9.6
Diffstat (limited to 'lib/unigbrk/ulc-grapheme-breaks.c')
-rw-r--r--lib/unigbrk/ulc-grapheme-breaks.c130
1 files changed, 130 insertions, 0 deletions
diff --git a/lib/unigbrk/ulc-grapheme-breaks.c b/lib/unigbrk/ulc-grapheme-breaks.c
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+/* Grapheme cluster breaks function.
+ Copyright (C) 2001-2003, 2006-2015 Free Software Foundation, Inc.
+ Written by Ben Pfaff <blp@cs.stanford.edu>, 2010,
+ based on code written by Bruno Haible <bruno@clisp.org>, 2009.
+
+ 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 "unigbrk.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+#include "c-ctype.h"
+#include "c-strcaseeq.h"
+#include "localcharset.h"
+#include "uniconv.h"
+
+static int
+is_utf8_encoding (const char *encoding)
+{
+ if (STRCASEEQ (encoding, "UTF-8", 'U', 'T', 'F', '-', '8', 0, 0, 0, 0))
+ return 1;
+ return 0;
+}
+
+#if C_CTYPE_ASCII
+/* Assume that every ASCII character starts a new grapheme, which is often
+ true, except that CR-LF is a single grapheme. */
+static void
+ascii_grapheme_breaks (const char *s, size_t n, char *p)
+{
+ size_t i;
+
+ p[0] = 1;
+ for (i = 1; i < n; i++)
+ {
+ bool is_ascii = c_isprint (s[i]) || c_isspace (s[i]);
+ p[i] = is_ascii && (s[i] != '\n' || s[i - 1] != '\r');
+ }
+}
+#endif
+
+/* Grapheme boundaries in a string in an arbitrary encoding.
+
+ We convert the input string to Unicode.
+
+ The standardized Unicode encodings are UTF-8, UCS-2, UCS-4, UTF-16,
+ UTF-16BE, UTF-16LE, UTF-7. UCS-2 supports only characters up to
+ \U0000FFFF. UTF-16 and variants support only characters up to
+ \U0010FFFF. UTF-7 is way too complex and not supported by glibc-2.1.
+ UCS-4 specification leaves doubts about endianness and byte order mark.
+ glibc currently interprets it as big endian without byte order mark,
+ but this is not backed by an RFC. So we use UTF-8. It supports
+ characters up to \U7FFFFFFF and is unambiguously defined. */
+
+void
+ulc_grapheme_breaks (const char *s, size_t n, char *p)
+{
+ if (n > 0)
+ {
+ const char *encoding = locale_charset ();
+
+ if (is_utf8_encoding (encoding))
+ u8_grapheme_breaks ((const uint8_t *) s, n, p);
+ else
+ {
+ /* Convert the string to UTF-8 and build a translation table
+ from offsets into s to offsets into the translated string. */
+ size_t *offsets = (size_t *) malloc (n * sizeof (size_t));
+
+ if (offsets != NULL)
+ {
+ uint8_t *t;
+ size_t m;
+
+ t = u8_conv_from_encoding (encoding, iconveh_question_mark,
+ s, n, offsets, NULL, &m);
+ if (t != NULL)
+ {
+ char *q = (char *) (m > 0 ? malloc (m) : NULL);
+
+ if (m == 0 || q != NULL)
+ {
+ size_t i;
+
+ /* Determine the grapheme breaks of the UTF-8 string. */
+ u8_grapheme_breaks (t, m, q);
+
+ /* Translate the result back to the original string. */
+ memset (p, 0, n);
+ for (i = 0; i < n; i++)
+ if (offsets[i] != (size_t)(-1))
+ p[i] = q[offsets[i]];
+
+ free (q);
+ free (t);
+ free (offsets);
+ return;
+ }
+ free (t);
+ }
+ free (offsets);
+ }
+
+ /* Impossible to convert. */
+#if C_CTYPE_ASCII
+ /* Fall back to ASCII as best we can. */
+ ascii_grapheme_breaks (s, n, p);
+#else
+ /* We cannot make any assumptions. */
+ p[0] = 1;
+ memset (p + 1, 0, n - 1);
+#endif
+ }
+ }
+}