1 files changed, 111 insertions, 0 deletions
diff --git a/lib/memcoll.c b/lib/memcoll.c
new file mode 100644
index 0000000..87bd0c3
--- /dev/null
+++ b/lib/memcoll.c
@@ -0,0 +1,111 @@
+/* Locale-specific memory comparison.
+
+   Copyright (C) 1999, 2002-2004, 2006, 2009-2022 Free Software Foundation,
+   Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Contributed by Paul Eggert <eggert@twinsun.com>.  */
+
+#include <config.h>
+
+#include "memcoll.h"
+
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+
+/* Compare S1 (with size S1SIZE) and S2 (with length S2SIZE) according
+   to the LC_COLLATE locale.  S1 and S2 are both blocks of memory with
+   nonzero sizes, and the last byte in each block must be a null byte.
+   Set errno to an error number if there is an error, and to zero
+   otherwise.  */
+static int
+strcoll_loop (char const *s1, size_t s1size, char const *s2, size_t s2size)
+{
+  int diff;
+
+  while (! (errno = 0, (diff = strcoll (s1, s2)) || errno))
+    {
+      /* strcoll found no difference, but perhaps it was fooled by NUL
+         characters in the data.  Work around this problem by advancing
+         past the NUL chars.  */
+      size_t size1 = strlen (s1) + 1;
+      size_t size2 = strlen (s2) + 1;
+      s1 += size1;
+      s2 += size2;
+      s1size -= size1;
+      s2size -= size2;
+
+      if (s1size == 0)
+        return - (s2size != 0);
+      if (s2size == 0)
+        return 1;
+    }
+
+  return diff;
+}
+
+/* Compare S1 (with length S1LEN) and S2 (with length S2LEN) according
+   to the LC_COLLATE locale.  S1 and S2 do not overlap, and are not
+   adjacent.  Perhaps temporarily modify the bytes after S1 and S2,
+   but restore their original contents before returning.  Set errno to an
+   error number if there is an error, and to zero otherwise.  */
+int
+memcoll (char *s1, size_t s1len, char *s2, size_t s2len)
+{
+  int diff;
+
+  /* strcoll is slow on many platforms, so check for the common case
+     where the arguments are bytewise equal.  Otherwise, walk through
+     the buffers using strcoll on each substring.  */
+
+  if (s1len == s2len && memcmp (s1, s2, s1len) == 0)
+    {
+      errno = 0;
+      diff = 0;
+    }
+  else
+    {
+      char n1 = s1[s1len];
+      char n2 = s2[s2len];
+
+      s1[s1len] = '\0';
+      s2[s2len] = '\0';
+
+      diff = strcoll_loop (s1, s1len + 1, s2, s2len + 1);
+
+      s1[s1len] = n1;
+      s2[s2len] = n2;
+    }
+
+  return diff;
+}
+
+/* Compare S1 (a memory block of size S1SIZE, with a NUL as last byte)
+   and S2 (a memory block of size S2SIZE, with a NUL as last byte)
+   according to the LC_COLLATE locale.  S1SIZE and S2SIZE must be > 0.
+   Set errno to an error number if there is an error, and to zero
+   otherwise.  */
+int
+memcoll0 (char const *s1, size_t s1size, char const *s2, size_t s2size)
+{
+  if (s1size == s2size && memcmp (s1, s2, s1size) == 0)
+    {
+      errno = 0;
+      return 0;
+    }
+  else
+    return strcoll_loop (s1, s1size, s2, s2size);
+}