[Cl-darcs-cvs] r88 - cl-darcs/trunk

[mhenoch at common-lisp.net]

Author: mhenoch
Date: Wed Feb 14 23:00:30 2007
New Revision: 88

Modified:
   cl-darcs/trunk/util.lisp
Log:
Combine regexps into one to reduce memory use.


Modified: cl-darcs/trunk/util.lisp
==============================================================================
--- cl-darcs/trunk/util.lisp	(original)
+++ cl-darcs/trunk/util.lisp	Wed Feb 14 23:00:30 2007
@@ -287,13 +287,23 @@
 (defun matches-one-of (regexps string)
   "Return true if some of REGEXPS match STRING.
 Cache scanners for faster execution beyond first time."
-  (dolist (regexp regexps)
-    (let ((scanner (or
-		    (gethash regexp *scanner-cache*)
-		    (setf (gethash regexp *scanner-cache*)
-			  (cl-ppcre:create-scanner regexp)))))
-      (when (cl-ppcre:scan scanner string)
-	(return t)))))
+  ;; These scanners use _a lot_ of memory, so we build just one, and
+  ;; hope that the exact combination of regexps will be used often
+  ;; enough.
+  (setq regexps (sort (copy-seq regexps) #'string>))
+  (let* ((combined-regexp
+	  (apply
+	   #'concatenate 'string
+	   (loop for regexp in regexps
+	      for n upfrom 0
+	      unless (zerop n) collect "|"
+	      collect regexp)))
+	 (scanner (or
+		   (gethash combined-regexp *scanner-cache*)
+		   (setf (gethash combined-regexp *scanner-cache*)
+			 (cl-ppcre:create-scanner combined-regexp)))))
+    (when (cl-ppcre:scan scanner string)
+      t)))
 
 (defun file-binary-p (repo filename)
   "Return true if FILENAME names a binary file.