1 files changed, 50 insertions, 0 deletions
diff --git a/lib/substring.c b/lib/substring.c
new file mode 100644
index 0000000..8ef7174
--- /dev/null
+++ b/lib/substring.c
@@ -0,0 +1,50 @@
+/* substring.c: copy a chunk from a string.
+
+Copyright (C) 1992 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 2, 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, write to the Free Software
+Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
+
+#include "config.h"
+
+
+/* Return a fresh copy of SOURCE[START..LIMIT], or NULL if LIMIT<START.
+   If LIMIT>strlen(START), it is reassigned. */
+
+string
+substring (string source, const unsigned start, const unsigned limit)
+{
+  string result;
+  unsigned this_char;
+  unsigned length = strlen (source);
+  unsigned lim = limit;
+
+  /* Upper bound out of range? */
+  if (lim >= length)
+    lim = length - 1;
+
+  /* Null substring? */
+  if (start > limit)
+    return "";
+
+  /* The `2' here is one for the null and one for limit - start inclusive. */
+  result = xmalloc (limit - start + 2);
+
+  for (this_char = start; this_char <= limit; this_char++)
+    result[this_char - start] = source[this_char];
+
+  result[this_char - start] = 0;
+
+  return result;
+}