--- chicken-2.0-orig/extras.scm	2005-07-12 05:48:49.000000000 -0500
+++ chicken-2.0.alejo/extras.scm	2005-07-28 12:15:42.000000000 -0500
@@ -1396,9 +1396,18 @@
 
 ;;; Utility definitions:
 
-(define hashtab-default-size 301)
+(define hashtab-default-size 307)
 (define hashtab-threshold 0.5)
-(define hashtab-primes-table '(301 613 997 1597 2011 2521 3001))
+
+; Predefined sizes for the hash tables:
+;
+; Start in 307; each element is the smallest prime that is at least twice as
+; bigger as the previous element in the list.  The last number is an
+; exception: it is the largest fixnum we can repressent.
+
+(define hashtab-primes-table '(307 617 1237 2477 4957 9923 19853 39709 79423 158849 317701 635413 1270849 2541701 5083423 10166857 20333759 40667527 81335063 162670129 325340273 650680571 1073741823))
+
+(define hashtab-max-size 1073741823)
 (define (hash-table? x) (##sys#structure? x 'hash-table))
 
 
@@ -1508,6 +1517,12 @@
       (##sys#check-structure ht 'hash-table 'hash-table-ref)
       (not (eq? unique (ref ht key unique))) ) ) )
 
+(define (hash-new-len tab req)
+  (if (or (fx>= (##sys#slot tab 0) req)
+	  (eq? (##sys#slot tab 1) '()))
+      (##sys#slot tab 0)
+      (hash-new-len (##sys#slot tab 1) req)))
+
 (define hash-table-update! 
   ;; This one was suggested by Sven Hartrumpf.
   (let ([eq0 eq?]
@@ -1521,16 +1536,12 @@
 	       (test (##sys#slot ht 3))
 	       (k (hashf key len))
 	       (c (fx+ (##sys#slot ht 2) 1)) )
-	  (if (fx>= c (inexact->exact (floor (* len hashtab-threshold))))
-	      (let* ((newlen
-		      (cond ((memq len hashtab-primes-table)
-			     => (lambda (n) 
-				  (let ((next (##sys#slot n 1)))
-				    (if (eq? next '())
-					(fx+ len 101) ; arbitrary
-					(##sys#slot next 0) ) ) ) )
-			    (else (fx+ len 101)) ) )
-		     (vec2 (make-vector newlen '())) )
+	  (if (and (fx>= c (inexact->exact (floor (* len hashtab-threshold))))
+		   (fx< len hashtab-max-size))
+	      (let ((vec2 (make-vector
+                            (hash-new-len hashtab-primes-table
+                                          (min hashtab-max-size (* len 2)))
+                            '())))
 		(hashtab-rehash vec vec2 hashf)
 		(##sys#setslot ht 1 vec2)
 		(restart) )