-;;; riece-cache.el --- LRU based cache management
+;;; riece-cache.el --- LRU cache
;; Copyright (C) 1998-2005 Daiki Ueno
;; Author: Daiki Ueno <ueno@unixuser.org>
;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs; see the file COPYING. If not, write to the
-;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
-;; Boston, MA 02111-1307, USA.
+;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+;; Boston, MA 02110-1301, USA.
;;; Code:
"Set previous of NODE to PREVIOUS."
(aset node 2 previous))
-(defun riece-cache-make-map (max-length)
- "Make riece-cache-map object."
+(defun riece-make-cache (max-length)
+ "Make riece-cache object."
(vector max-length (make-vector (* max-length 2) 0) 0 nil nil))
-(defun riece-cache-map-max-length (map)
- "Return max-length of MAP."
- (aref map 0))
+(defun riece-cache-max-length (cache)
+ "Return max-length of CACHE."
+ (aref cache 0))
-(defun riece-cache-map-hash-obarray (map)
- "Return hash-obarray of MAP."
- (aref map 1))
+(defun riece-cache-hash-obarray (cache)
+ "Return hash-obarray of CACHE."
+ (aref cache 1))
-(defun riece-cache-map-hash-length (map)
- "Return hash-length of MAP."
- (aref map 2))
+(defun riece-cache-hash-length (cache)
+ "Return hash-length of CACHE."
+ (aref cache 2))
-(defun riece-cache-map-set-hash-length (map hash-length)
- "Set hash-length of MAP to HASH-LENGTH."
- (aset map 2 hash-length))
+(defun riece-cache-set-hash-length (cache hash-length)
+ "Set hash-length of CACHE to HASH-LENGTH."
+ (aset cache 2 hash-length))
-(defun riece-cache-map-first (map)
- "Return first of MAP."
- (aref map 3))
+(defun riece-cache-first (cache)
+ "Return first of CACHE."
+ (aref cache 3))
-(defun riece-cache-map-set-first (map first)
- "Set first of MAP to FIRST."
- (aset map 3 first))
+(defun riece-cache-set-first (cache first)
+ "Set first of CACHE to FIRST."
+ (aset cache 3 first))
-(defun riece-cache-map-last (map)
- "Return last of MAP."
- (aref map 4))
+(defun riece-cache-last (cache)
+ "Return last of CACHE."
+ (aref cache 4))
-(defun riece-cache-map-set-last (map last)
- "Set last of MAP to LAST."
- (aset map 4 last))
+(defun riece-cache-set-last (cache last)
+ "Set last of CACHE to LAST."
+ (aset cache 4 last))
-(defalias 'riece-make-cache 'riece-cache-make-map)
+(defun riece-cache-contains (cache key)
+ "Return t if CACHE contains an entry whose key is KEY."
+ (intern-soft key (riece-cache-hash-obarray cache)))
-(defun riece-cache-contains (map key)
- (intern-soft key (riece-cache-map-hash-obarray map)))
-
-(defun riece-cache-get (map key)
- (let ((node (riece-cache-get-node map key)))
+(defun riece-cache-get (cache key)
+ "Return the value associated with KEY in CACHE.
+If KEY is not associated in CACHE, it returns nil."
+ (let ((node (riece-cache-get-node cache key)))
(if node
(riece-cache-node-value node))))
-(defun riece-cache-get-node (map key)
- (let ((symbol (intern-soft key (riece-cache-map-hash-obarray map)))
+(defun riece-cache-get-node (cache key)
+ "Return a node object associcated with KEY in CACHE.
+If KEY is not associated in CACHE, it returns nil."
+ (let ((symbol (intern-soft key (riece-cache-hash-obarray cache)))
previous next last node)
(when symbol
(setq node (symbol-value symbol)
previous (riece-cache-node-previous node)
next (riece-cache-node-next node)
- last (riece-cache-map-last map))
+ last (riece-cache-last cache))
(if previous
(riece-cache-node-set-next previous next))
(if next
(riece-cache-node-set-next node nil)
(riece-cache-node-set-previous node last)
(riece-cache-node-set-next last node)
- (riece-cache-map-set-last map node)
- (if (and (eq node (riece-cache-map-first map)) next)
- (riece-cache-map-set-first map next))
+ (riece-cache-set-last cache node)
+ (if (and (eq node (riece-cache-first cache)) next)
+ (riece-cache-set-first cache next))
node)))
-(defun riece-cache-delete (map key)
- (let ((symbol (intern-soft key (riece-cache-map-hash-obarray map)))
+(defun riece-cache-delete (cache key)
+ "Remove an entry from CACHE whose key is KEY."
+ (let ((symbol (intern-soft key (riece-cache-hash-obarray cache)))
previous next node)
(when symbol
(setq node (symbol-value symbol)
(riece-cache-node-set-next previous next))
(if next
(riece-cache-node-set-previous next previous))
- (if (eq (riece-cache-map-last map) node)
- (riece-cache-map-set-last map previous))
- (if (eq (riece-cache-map-first map) node)
- (riece-cache-map-set-first map next))
- (unintern symbol (riece-cache-map-hash-obarray map))
- (riece-cache-map-set-hash-length map
- (1- (riece-cache-map-hash-length map)))
+ (if (eq (riece-cache-last cache) node)
+ (riece-cache-set-last cache previous))
+ (if (eq (riece-cache-first cache) node)
+ (riece-cache-set-first cache next))
+ (unintern symbol (riece-cache-hash-obarray cache))
+ (riece-cache-set-hash-length cache
+ (1- (riece-cache-hash-length cache)))
(riece-cache-node-value node))))
-(defun riece-cache-set (map key value)
- (let ((node (riece-cache-get-node map key)))
+(defun riece-cache-set (cache key value)
+ "Associate KEY with VALUE in CACHE."
+ (let ((node (riece-cache-get-node cache key)))
(if node
(riece-cache-node-set-value node value)
- (if (>= (riece-cache-map-hash-length map)
- (riece-cache-map-max-length map))
- (riece-cache-delete map (riece-cache-node-key
- (riece-cache-map-first map))))
- (setq node (riece-cache-make-node key value (riece-cache-map-last map)))
- (set (intern key (riece-cache-map-hash-obarray map)) node)
- (riece-cache-map-set-hash-length map
- (1+ (riece-cache-map-hash-length map)))
- (unless (riece-cache-map-first map)
- (riece-cache-map-set-first map node))
- (if (riece-cache-map-last map)
- (progn
- (riece-cache-node-set-next (riece-cache-map-last map) node)
- (riece-cache-node-set-previous node (riece-cache-map-last map))))
- (riece-cache-map-set-last map node))))
+ (if (>= (riece-cache-hash-length cache)
+ (riece-cache-max-length cache))
+ (riece-cache-delete cache (riece-cache-node-key
+ (riece-cache-first cache))))
+ (setq node (riece-cache-make-node key value (riece-cache-last cache)))
+ (set (intern key (riece-cache-hash-obarray cache)) node)
+ (riece-cache-set-hash-length cache
+ (1+ (riece-cache-hash-length cache)))
+ (unless (riece-cache-first cache)
+ (riece-cache-set-first cache node))
+ (when (riece-cache-last cache)
+ (riece-cache-node-set-next (riece-cache-last cache) node)
+ (riece-cache-node-set-previous node (riece-cache-last cache)))
+ (riece-cache-set-last cache node))))
(provide 'riece-cache)
projects / riece / blobdiff