new file mode 100644
--- /dev/null
+++ b/lib/linebuffer.c
@@ -0,0 +1,91 @@
+/* linebuffer.c -- read arbitrarily long lines
+   Copyright (C) 1986, 1991 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.  */
+
+/* Written by Richard Stallman. */
+
+#include <stdio.h>
+#include "linebuffer.h"
+
+char *xmalloc ();
+char *xrealloc ();
+void free ();
+
+/* Initialize linebuffer LINEBUFFER for use. */
+
+void
+initbuffer (linebuffer)
+     struct linebuffer *linebuffer;
+{
+  linebuffer->length = 0;
+  linebuffer->size = 200;
+  linebuffer->buffer = (char *) xmalloc (linebuffer->size);
+}
+
+/* Read an arbitrarily long line of text from STREAM into LINEBUFFER.
+   Remove any newline.  Does not null terminate.
+   Return LINEBUFFER, except at end of file return 0.  */
+
+struct linebuffer *
+readline (linebuffer, stream)
+     struct linebuffer *linebuffer;
+     FILE *stream;
+{
+  int c;
+  char *buffer = linebuffer->buffer;
+  char *p = linebuffer->buffer;
+  char *end = buffer + linebuffer->size; /* Sentinel. */
+
+  if (feof (stream))
+    {
+      linebuffer->length = 0;
+      return 0;
+    }
+
+  while (1)
+    {
+      c = getc (stream);
+      if (p == end)
+	{
+	  linebuffer->size *= 2;
+	  buffer = (char *) xrealloc (buffer, linebuffer->size);
+	  p += buffer - linebuffer->buffer;
+	  linebuffer->buffer = buffer;
+	  end = buffer + linebuffer->size;
+	}
+      if (c == EOF || c == '\n')
+	break;
+      *p++ = c;
+    }
+
+  if (feof (stream) && p == buffer)
+    {
+      linebuffer->length = 0;
+      return 0;
+    }
+  linebuffer->length = p - linebuffer->buffer;
+  return linebuffer;
+}
+
+/* Free linebuffer LINEBUFFER and its data, all allocated with malloc. */
+
+void
+freebuffer (linebuffer)
+     struct linebuffer *linebuffer;
+{
+  free (linebuffer->buffer);
+  free (linebuffer);
+}