Import Upstream version 5b3upstream/5b3

1 files changed, 30 insertions, 1 deletions

diff --git a/rope.c b/rope.c
index c922046..94b6631 100644
--- a/rope.c
+++ b/rope.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995 Free Software Foundation, Inc.
+/* Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1997 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
@@ -330,6 +330,35 @@ unsigned long scm_addr(args, s_name)
 }
 #endif /* ARRAYS */
 
+/* scm_cell_p() returns !0 if the SCM argument `x' is cell-aligned and
+   points into a valid heap segment.  This code is duplicated from
+   mark_locations() and obunhash() in "sys.c", which means that
+   changes to these routines must be coordinated. */
+
+#include "continue.h"
+extern sizet hplim_ind;
+extern CELLPTR *hplims;
+
+int scm_cell_p(x)
+     SCM x;
+{
+	register int i, j;
+	register CELLPTR ptr;
+	if NCELLP(x) return 0;
+	ptr = (CELLPTR)SCM2PTR(x);
+	i = 0;
+	j = hplim_ind;
+	do {
+		if PTR_GT(hplims[i++], ptr) break;
+		if PTR_LE(hplims[--j], ptr) break;
+		if ((i != j)
+		    && PTR_LE(hplims[i++], ptr)
+		    && PTR_GT(hplims[--j], ptr)) continue;
+		return !0; /* NFREEP(x) */
+	} while(i<j);
+	return 0;
+}
+
 void init_rope()
 {
 }