1 files changed, 130 insertions, 0 deletions
diff --git a/lib/unigbrk/ulc-grapheme-breaks.c b/lib/unigbrk/ulc-grapheme-breaks.c
new file mode 100644
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--- /dev/null
+++ b/lib/unigbrk/ulc-grapheme-breaks.c
@@ -0,0 +1,130 @@
+/* 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
+        }
+    }
+}