From a197a875097514453e2fc0722236d2810ab50813 Mon Sep 17 00:00:00 2001
From: Chris Hanson <org/chris-hanson/cph>
Date: Sun, 10 Jan 1993 10:48:22 +0000
Subject: [PATCH] Change GC undo truncation code to use buffer-local values of
 limit variables.

---
 v7/src/edwin/undo.scm | 35 +++++++++++++++++------------------
 1 file changed, 17 insertions(+), 18 deletions(-)

diff --git a/v7/src/edwin/undo.scm b/v7/src/edwin/undo.scm
index 3c9c76125..26e5a318c 100644
--- a/v7/src/edwin/undo.scm
+++ b/v7/src/edwin/undo.scm
@@ -1,6 +1,6 @@
 ;;; -*-Scheme-*-
 ;;;
-;;;	$Id: undo.scm,v 1.51 1993/01/09 01:16:23 cph Exp $
+;;;	$Id: undo.scm,v 1.52 1993/01/10 10:48:22 cph Exp $
 ;;;
 ;;;	Copyright (c) 1985, 1989-93 Massachusetts Institute of Technology
 ;;;
@@ -151,7 +151,8 @@
 This limit is applied when garbage collection happens.
 The size is counted as the number of bytes occupied,
 which includes both the saved text and other data."
-  20000)
+  20000
+  exact-nonnegative-integer?)
 
 (define-variable undo-strong-limit
   "Don't keep more than this much size of undo information.
@@ -159,7 +160,8 @@ A command that pushes past this size is itself forgotten.
 This limit is applied when garbage collection happens.
 The size is counted as the number of bytes occupied,
 which includes both the saved text and other data."
-  30000)
+  30000
+  exact-nonnegative-integer?)
 
 (define (truncate-buffer-undo-lists!)
   ;; This procedure must be careful about accessing editor data
@@ -167,22 +169,19 @@ which includes both the saved text and other data."
   ;; the editor does not exist or is not running.  It would actually
   ;; prefer to be run *before* the GC, but that's not possible now.
   (if edwin-editor
-      (let ((bytes-per-word
+      (let ((bytes/word
 	     (vector-ref ((ucode-primitive gc-space-status 0)) 0)))
-	(let ((min-size
-	       (integer-round (variable-default-value
-			       (ref-variable-object undo-limit))
-			      bytes-per-word))
-	      (max-size
-	       (integer-round (variable-default-value
-			       (ref-variable-object undo-strong-limit))
-			      bytes-per-word)))
-	  (do ((buffers (bufferset-buffer-list (editor-bufferset edwin-editor))
-			(cdr buffers)))
-	      ((null? buffers))
-	    (truncate-undo-data! (group-undo-data (buffer-group (car buffers)))
-				 min-size
-				 max-size))))))
+	(let ((words->bytes
+	       (lambda (words)
+		 (round (/ words bytes/word)))))
+	(do ((buffers (bufferset-buffer-list (editor-bufferset edwin-editor))
+		      (cdr buffers)))
+	    ((null? buffers))
+	  (let ((buffer (car buffers)))
+	    (truncate-undo-data!
+	     (group-undo-data (buffer-group buffer))
+	     (words->bytes (ref-variable undo-limit buffer))
+	     (words->bytes (ref-variable undo-strong-limit buffer)))))))))
 
 (add-gc-daemon! truncate-buffer-undo-lists!)
 
-- 
2.25.1