X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fcode%2Ftarget-sxhash.lisp;h=5fb976226b61a9144c08d80930b759adad32b472;hb=073501ed49414d9638cb41c05fb80627529f796d;hp=96d7b1260ef1f3c0238d211b7e01fb0d1ca63946;hpb=a530bbe337109d898d5b4a001fc8f1afa3b5dc39;p=sbcl.git

diff --git a/src/code/target-sxhash.lisp b/src/code/target-sxhash.lisp
index 96d7b12..5fb9762 100644
--- a/src/code/target-sxhash.lisp
+++ b/src/code/target-sxhash.lisp
@@ -11,18 +11,13 @@
 
 (in-package "SB!IMPL")
 
-(file-comment
-  "$Header$")
-
 ;;; the depthoid explored when calculating hash values
 ;;;
 ;;; "Depthoid" here is a sort of mixture of what Common Lisp ordinarily calls
 ;;; depth and what Common Lisp ordinarily calls length; it's incremented either
 ;;; when we descend into a compound object or when we step through elements of
 ;;; a compound object.
-(eval-when (:compile-toplevel :load-toplevel :execute)
 (defconstant +max-hash-depthoid+ 4)
-) ; EVAL-WHEN
 
 ;;;; mixing hash values
 
@@ -104,7 +99,7 @@
 ;;;	     (unless (string= (gethash hash ht) string)
 ;;;	       (format t "collision: ~S ~S~%" string (gethash hash ht)))
 ;;;	     (setf (gethash hash ht) string))))
-;;;     (format t "final count=~D~%" (hash-table-count ht)))
+;;;     (format t "final count=~W~%" (hash-table-count ht)))
 
 (defun %sxhash-simple-string (x)
   (declare (optimize speed))
@@ -122,7 +117,7 @@
 (defun sxhash (x)
   (labels ((sxhash-number (x)
 	     (etypecase x
-	       (fixnum (sxhash x)) ; through DEFTRANSFORM
+	       (fixnum (sxhash x))	; through DEFTRANSFORM
 	       (integer (sb!bignum:sxhash-bignum x))
 	       (single-float (sxhash x)) ; through DEFTRANSFORM
 	       (double-float (sxhash x)) ; through DEFTRANSFORM
@@ -150,9 +145,15 @@
 		    (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))
 	       (symbol (sxhash x)) ; through DEFTRANSFORM
-	       (number (sxhash-number x))
 	       (array
 		(typecase x
 		  (simple-string (sxhash x)) ; through DEFTRANSFORM
@@ -166,6 +167,8 @@
 	       (character
 		(logxor 72185131
 			(sxhash (char-code x)))) ; through DEFTRANSFORM
+	       ;; general, inefficient case of NUMBER
+	       (number (sxhash-number x))
 	       (t 42))))
     (sxhash-recurse x)))
 
@@ -324,88 +327,3 @@
 		     (mixf result (number-psxhash (realpart key)))
 		     (mixf result (number-psxhash (imagpart key)))
 		     result))))))
-
-;;; SXHASH and PSXHASH should distribute hash values well over the
-;;; space of possible values, so that collisions between the hash values
-;;; of unequal objects should be very uncommon.
-;;;
-;;; FIXME: These tests should be enabled once the rest of the system is
-;;; stable. (For now, I don't want to mess with things like making sure
-;;; that bignums are hashed uniquely.)
-;;;#!+sb-test
-#+nil
-(let* ((test-cases `((0 . 1)
-		     (0 . 1)
-		     (1 . 0)
-		     ((1 . 0) (0 . 0))
-		     ((0 . 1) (0 . 0))
-		     ((0 . 0) (1 . 0))
-		     ((0 . 0) (0 . 1))
-		     #((1 . 0) (0 . 0))
-		     #((0 . 1) (0 . 0))
-		     #((0 . 0) (1 . 0))
-		     #((0 . 0) (0 . 1))
-		     #((1 . 0) (0 . 0))
-		     #((0 1) (0 0))
-		     #((0 0) (1 0))
-		     #((0 0) (0 1))
-		     #(#(1 0) (0 0))
-		     #(#(0 1) (0 0))
-		     #(#(0 0) (1 0))
-		     #(#(0 0) (0 1))
-		     #(#*00 #*10)
-		     #(#(0 0) (0 1.0d0))
-		     #(#(-0.0d0 0) (1.0 0))
-		     ;; KLUDGE: Some multi-dimensional array test cases would
-		     ;; be good here too, but currently SBCL isn't smart enough
-		     ;; to dump them as literals, and I'm too lazy to make
-		     ;; code to create them at run time. -- WHN 20000111
-		     44 44.0 44.0d0
-		     44 44.0 44.0d0
-		     -44 -44.0 -44.0d0
-		     0 0.0 0.0d0
-		     -0 -0.0 -0.0d0
-		     -121 -121.0 -121.0d0
-		     3/4 0.75 0.75d0
-		     -3/4 -0.75 -0.75d0
-		     44.1 44.1d0
-		     45 45.0 45.0d0
-		     ,(expt 2 33) ,(expt 2.0 33) ,(expt 2.0d0 33)
-		     ,(- (expt 1/2 50)) ,(- (expt 0.5 50)) ,(- (expt 0.5d0 50))
-		     ,(- (expt 1/2 50)) ,(- (expt 0.5 50)) ,(- (expt 0.5d0 50))
-		     #c(1.0 2.0) #c(1 2.0) #c(1.5 -3/2) #c(3/2 -3/2) #c(0 1)
-		     #c(1.0 2.0) #c(1 2.0) #c(1.5 -3/2) #c(3/2 -3/2) #c(0 1)
-		     ,(make-hash-table)
-		     ,(make-hash-table :test 'equal)
-		     "abc" "ABC" "aBc" 'abc #(#\a #\b #\c) #(a b c) #("A" b c)
-		     "abcc"
-		     "" #* #() () (()) #(()) (#())
-		     "" #* #() () (()) #(()) (#())
-		     #\x #\X #\*
-		     #\x #\X #\*)))
-  (dolist (i test-cases)
-    (unless (typep (sxhash i) '(and fixnum unsigned-byte))
-      (error "bad SXHASH behavior for ~S" i))
-    (unless (typep (psxhash i) '(and fixnum unsigned-byte))
-      (error "bad PSXHASH behavior for ~S" i))
-    (dolist (j test-cases)
-      (flet ((t->boolean (x) (if x t nil)))
-	;; Note: It's possible that a change to the hashing algorithm could
-	;; leave it correct but still cause this test to bomb by causing an
-	;; unlucky random collision. That's not very likely (since there are
-	;; (EXPT 2 29) possible hash values and only on the order of 100 test
-	;; cases, but it's probably worth checking if you are getting a
-	;; mystifying error from this test.
-	(unless (eq (t->boolean (equal i j))
-		    (t->boolean (= (sxhash i) (sxhash j))))
-	  (error "bad SXHASH behavior for ~S ~S" i j))
-	(unless (eq (t->boolean (equalp i j))
-		    (t->boolean (= (psxhash i) (psxhash j))))
-	  (error "bad PSXHASH behavior for ~S ~S" i j))))))
-
-;;; FIXME: Test that the the hash functions can deal with common cases without
-;;; consing.
-;(defun consless-test ()
-;  (dotimes (j 100000)
-;    (dolist (i '("yo" #(1 2 3) #2A((1 2) (1 2)) (1 2 (3)) 1 1.0 1.0d0))
-;      (psxhash i))))