1 files changed, 92 insertions, 0 deletions
diff --git a/lib/stpncpy.c b/lib/stpncpy.c
new file mode 100644
index 0000000..0a720a0
--- /dev/null
+++ b/lib/stpncpy.c
@@ -0,0 +1,92 @@
+/* Copyright (C) 1993, 1995-1997, 2002-2003, 2005-2007, 2009-2022 Free Software
+ * Foundation, Inc.
+
+   NOTE: The canonical source of this file is maintained with the GNU C Library.
+   Bugs can be reported to bug-glibc@gnu.org.
+
+   This file 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 2.1 of the
+   License, or (at your option) any later version.
+
+   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 for more details.
+
+   You should have received a copy of the GNU Lesser General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* This is almost copied from strncpy.c, written by Torbjorn Granlund.  */
+
+#include <config.h>
+
+/* Specification.  */
+#include <string.h>
+
+#ifndef weak_alias
+# define __stpncpy stpncpy
+#endif
+
+/* Copy no more than N bytes of SRC to DST, returning a pointer past the
+   last non-NUL byte written into DST.  */
+char *
+(__stpncpy) (char *dest, const char *src, size_t n)
+{
+  char c;
+  char *s = dest;
+
+  if (n >= 4)
+    {
+      size_t n4 = n >> 2;
+
+      for (;;)
+        {
+          c = *src++;
+          *dest++ = c;
+          if (c == '\0')
+            break;
+          c = *src++;
+          *dest++ = c;
+          if (c == '\0')
+            break;
+          c = *src++;
+          *dest++ = c;
+          if (c == '\0')
+            break;
+          c = *src++;
+          *dest++ = c;
+          if (c == '\0')
+            break;
+          if (--n4 == 0)
+            goto last_chars;
+        }
+      n -= dest - s;
+      goto zero_fill;
+    }
+
+ last_chars:
+  n &= 3;
+  if (n == 0)
+    return dest;
+
+  for (;;)
+    {
+      c = *src++;
+      --n;
+      *dest++ = c;
+      if (c == '\0')
+        break;
+      if (n == 0)
+        return dest;
+    }
+
+ zero_fill:
+  while (n-- > 0)
+    dest[n] = '\0';
+
+  return dest - 1;
+}
+#ifdef weak_alias
+weak_alias (__stpncpy, stpncpy)
+#endif