(in-package "SB!IMPL")
-(file-comment
- "$Header$")
-
-;;; an internal tag for marking empty slots
-;;;
-;;; CMU CL 18b used :EMPTY for this purpose, which was somewhat nasty
-;;; since it's easily accessible to the user, so that e.g.
-;;; (DEFVAR *HT* (MAKE-HASH-TABLE))
-;;; (SETF (GETHASH :EMPTY *HT*) :EMPTY)
-;;; (MAPHASH (LAMBDA (K V) (FORMAT T "~&~S ~S~%" K V)))
-;;; gives no output -- oops!
-;;;
-;;; Note that as of version 0.6.6 there's a dependence in the gencgc.c
-;;; code on this value being a symbol. (This is only one of many nasty
-;;; dependencies between that code and this, alas.)
-(defconstant +empty-ht-slot+ '%empty-ht-slot%)
-;;; KLUDGE: Using a private symbol still leaves us vulnerable to users
-;;; getting nonconforming behavior by messing around with
-;;; DO-ALL-SYMBOLS. That seems like a fairly obscure problem, so for
-;;; now we just don't worry about it. If for some reason it becomes
-;;; worrisome and the magic value needs replacement:
-;;; * The replacement value needs to be LOADable with EQL preserved,
-;;; so that macroexpansion for WITH-HASH-TABLE-ITERATOR will work
-;;; when compiled into a file and loaded back into SBCL.
-;;; (Thus, just uninterning %EMPTY-HT-SLOT% doesn't work.)
-;;; * The replacement value needs to be acceptable to the
-;;; low-level gencgc.lisp hash table scavenging code.
-;;; * The change will break binary compatibility, since comparisons
-;;; against the value used at the time of compilation are wired
-;;; into FASL files.
-;;; -- WHN 20000622
-
;;; HASH-TABLE is implemented as a STRUCTURE-OBJECT.
(sb!xc:defstruct (hash-table (:constructor %make-hash-table))
- ;; The type of hash table this is. Only used for printing and as part of
- ;; the exported interface.
+ ;; The type of hash table this is. Only used for printing and as
+ ;; part of the exported interface.
(test (required-argument) :type symbol :read-only t)
- ;; The function used to compare two keys. Returns T if they are the same
- ;; and NIL if not.
+ ;; The function used to compare two keys. Returns T if they are the
+ ;; same and NIL if not.
(test-fun (required-argument) :type function :read-only t)
- ;; The function used to compute the hashing of a key. Returns two values:
- ;; the index hashing and T if that might change with the next GC.
+ ;; The function used to compute the hashing of a key. Returns two
+ ;; values: the index hashing and T if that might change with the
+ ;; next GC.
(hash-fun (required-argument) :type function :read-only t)
- ;; How much to grow the hash table by when it fills up. If an index, then
- ;; add that amount. If a floating point number, then multiple it by that.
+ ;; how much to grow the hash table by when it fills up. If an index,
+ ;; then add that amount. If a floating point number, then multiply
+ ;; it by that.
(rehash-size (required-argument) :type (or index (single-float (1.0)))
:read-only t)
- ;; How full the hash table has to get before we rehash.
+ ;; how full the hash table has to get before we rehash
(rehash-threshold (required-argument) :type (single-float (0.0) 1.0)
:read-only t)
- ;; The number of entries before a rehash, just the one less than the
+ ;; The number of entries before a rehash, just one less than the
;; size of the next-vector, hash-vector, and half the size of the
;; kv-vector.
(rehash-trigger (required-argument) :type index)
(number-entries 0 :type index)
;; The Key-Value pair vector.
(table (required-argument) :type simple-vector)
- ;; True if this is a weak hash table, meaning that key->value mappings will
- ;; disappear if there are no other references to the key. Note: this only
- ;; matters if the hash function indicates that the hashing is EQ based.
+ ;; True if this is a weak hash table, meaning that key->value
+ ;; mappings will disappear if there are no other references to the
+ ;; key. Note: this only matters if the hash function indicates that
+ ;; the hashing is EQ based.
(weak-p nil :type (member t nil))
;; Index into the next-vector, chaining together buckets that need
;; to be rehashed because their hashing is EQ based and the key has
;; hash associated with the key, saving recalculation. Could be
;; useful for EQL, and EQUAL hash tables. This table is not needed
;; for EQ hash tables, and when present the value of #x8000000
- ;; represents EQ-based hashing on the respective Key.
+ ;; represents EQ-based hashing on the respective key.
(hash-vector nil :type (or null (simple-array (unsigned-byte 32) (*)))))
\f
(defmacro-mundanely with-hash-table-iterator ((function hash-table) &body body)
(let ((key (aref kv-vector (* 2 index)))
(value (aref kv-vector (1+ (* 2 index)))))
(incf index)
- (unless (and (eq key '#.+empty-ht-slot+)
- (eq value '#.+empty-ht-slot+))
+ (unless (and (eq key +empty-ht-slot+)
+ (eq value +empty-ht-slot+))
(return (values t key value))))))))
#',function))))
(macrolet ((,function () '(funcall ,n-function)))
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