X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;ds=sidebyside;f=src%2Fcode%2Ftarget-sxhash.lisp;h=0b65801e738c64a2384863f5f269dcc181579ca9;hb=a3ab89c1db0dd9bfb911532ca134be16f16c4c1b;hp=5fb976226b61a9144c08d80930b759adad32b472;hpb=f4a7d6c4a2a4f846ad353dddb922dd8967f998e5;p=sbcl.git

diff --git a/src/code/target-sxhash.lisp b/src/code/target-sxhash.lisp
index 5fb9762..0b65801 100644
--- a/src/code/target-sxhash.lisp
+++ b/src/code/target-sxhash.lisp
@@ -26,9 +26,9 @@
 ;;; desiderata:
 ;;;   * Non-commutativity keeps us from hashing e.g. #(1 5) to the
 ;;;     same value as #(5 1), and ending up in real trouble in some
-;;;     special cases like bit vectors the way that CMUCL SXHASH 18b
+;;;     special cases like bit vectors the way that CMUCL 18b SXHASH 
 ;;;     does. (Under CMUCL 18b, SXHASH of any bit vector is 1..)
-;;;   * We'd like to scatter our hash values the entire possible range
+;;;   * We'd like to scatter our hash values over the entire possible range
 ;;;     of values instead of hashing small or common key values (like
 ;;;     2 and NIL and #\a) to small FIXNUMs the way that the CMUCL 18b
 ;;;     SXHASH function does, again helping to avoid pathologies like
@@ -115,6 +115,9 @@
 ;;;; the SXHASH function
 
 (defun sxhash (x)
+  ;; profiling SXHASH is hard, but we might as well try to make it go
+  ;; fast, in case it is the bottleneck somwhere.  -- CSR, 2003-03-14
+  (declare (optimize speed))
   (labels ((sxhash-number (x)
 	     (etypecase x
 	       (fixnum (sxhash x))	; through DEFTRANSFORM
@@ -135,7 +138,7 @@
 	   (sxhash-recurse (x &optional (depthoid +max-hash-depthoid+))
 	     (declare (type index depthoid))
 	     (typecase x
-	       (list
+	       (cons
 		(if (plusp depthoid)
 		    (mix (sxhash-recurse (car x) (1- depthoid))
 			 (sxhash-recurse (cdr x) (1- depthoid)))
@@ -145,30 +148,28 @@
 		    (logxor 422371266
 			    (sxhash ; through DEFTRANSFORM
 			     (class-name (layout-class (%instance-layout x)))))
-		    ;; Nice though it might be to return a nontrivial
-		    ;; hash value for other instances (especially
-		    ;; STANDARD-OBJECTs) there seems to be no good way
-		    ;; to do so. We can't even do the CLASS-NAME trick
-		    ;; (as used above for STRUCTURE-OBJECT) because
-		    ;; then CHANGE-CLASS would cause SXHASH values to
-		    ;; change, ouch! -- WHN recording wisdom of CSR
-		    309518995))
+		    (sxhash-instance x)))
 	       (symbol (sxhash x)) ; through DEFTRANSFORM
 	       (array
 		(typecase x
 		  (simple-string (sxhash x)) ; through DEFTRANSFORM
 		  (string (%sxhash-substring x))
-		  (bit-vector (let ((result 410823708))
-				(declare (type fixnum result))
-				(dotimes (i (min depthoid (length x)))
-				  (mixf result (aref x i)))
-				result))
+		  (simple-bit-vector (sxhash x)) ; through DEFTRANSFORM
+		  (bit-vector
+		   ;; FIXME: It must surely be possible to do better
+		   ;; than this.  The problem is that a non-SIMPLE
+		   ;; BIT-VECTOR could be displaced to another, with a
+		   ;; non-zero offset -- so that significantly more
+		   ;; work needs to be done using the %RAW-BITS
+		   ;; approach.  This will probably do for now.
+		   (sxhash-recurse (copy-seq x) depthoid))
 		  (t (logxor 191020317 (sxhash (array-rank x))))))
 	       (character
 		(logxor 72185131
 			(sxhash (char-code x)))) ; through DEFTRANSFORM
 	       ;; general, inefficient case of NUMBER
 	       (number (sxhash-number x))
+	       (generic-function (sxhash-instance x))
 	       (t 42))))
     (sxhash-recurse x)))
 
@@ -193,7 +194,7 @@
     (array (array-psxhash key depthoid))
     (hash-table (hash-table-psxhash key))
     (structure-object (structure-object-psxhash key depthoid))
-    (list (list-psxhash key depthoid))
+    (cons (list-psxhash key depthoid))
     (number (number-psxhash key))
     (character (sxhash (char-upcase key)))
     (t (sxhash key))))