ikarus/scheme/ikarus.hash-tables.ss

345 lines
10 KiB
Scheme

;;; Ikarus Scheme -- A compiler for R6RS Scheme.
;;; Copyright (C) 2006,2007 Abdulaziz Ghuloum
;;;
;;; This program is free software: you can redistribute it and/or modify
;;; it under the terms of the GNU General Public License version 3 as
;;; published by the Free Software Foundation.
;;;
;;; This program is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
;;; General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with this program. If not, see <http://www.gnu.org/licenses/>.
(library (ikarus hash-tables)
(export make-eq-hashtable hashtable-ref hashtable-set! hashtable?
hashtable-size hashtable-delete! hashtable-contains?
hashtable-update! hashtable-keys hashtable-mutable?
hashtable-clear!)
(import
(ikarus system $pairs)
(ikarus system $vectors)
(ikarus system $tcbuckets)
(ikarus system $fx)
(except (ikarus) make-eq-hashtable hashtable-ref hashtable-set! hashtable?
hashtable-size hashtable-delete! hashtable-contains?
hashtable-update! hashtable-keys hashtable-mutable?
hashtable-clear!))
(define-struct hasht (vec count tc mutable?))
;;; directly from Dybvig's paper
(define tc-pop
(lambda (tc)
(let ([x ($car tc)])
(if (eq? x ($cdr tc))
#f
(let ([v ($car x)])
($set-car! tc ($cdr x))
($set-car! x #f)
($set-cdr! x #f)
v)))))
(define-syntax inthash
(syntax-rules ()
[(_ x) x]))
;;; assq-like lookup
(define direct-lookup
(lambda (x b)
(if (fixnum? b)
#f
(if (eq? x ($tcbucket-key b))
b
(direct-lookup x ($tcbucket-next b))))))
(define rehash-lookup
(lambda (h tc x)
(cond
[(tc-pop tc) =>
(lambda (b)
(if (eq? ($tcbucket-next b) #f)
(rehash-lookup h tc x)
(begin
(re-add! h b)
(if (eq? x ($tcbucket-key b))
b
(rehash-lookup h tc x)))))]
[else #f])))
(define get-bucket-index
(lambda (b)
(let ([next ($tcbucket-next b)])
(if (fixnum? next)
next
(get-bucket-index next)))))
(define replace!
(lambda (lb x y)
(let ([n ($tcbucket-next lb)])
(cond
[(eq? n x)
($set-tcbucket-next! lb y)
(void)]
[else
(replace! n x y)]))))
(define re-add!
(lambda (h b)
(let ([vec (hasht-vec h)]
[next ($tcbucket-next b)])
;;; first remove it from its old place
(let ([idx
(if (fixnum? next)
next
(get-bucket-index next))])
(let ([fst ($vector-ref vec idx)])
(cond
[(eq? fst b)
($vector-set! vec idx next)]
[else
(replace! fst b next)])))
;;; reset the tcbucket-tconc FIRST
($set-tcbucket-tconc! b (hasht-tc h))
;;; then add it to the new place
(let ([k ($tcbucket-key b)])
(let ([ih (inthash (pointer-value k))])
(let ([idx ($fxlogand ih ($fx- ($vector-length vec) 1))])
(let ([n ($vector-ref vec idx)])
($set-tcbucket-next! b n)
($vector-set! vec idx b)
(void))))))))
(define unlink!
(lambda (h b)
(let ([vec (hasht-vec h)]
[next ($tcbucket-next b)])
;;; first remove it from its old place
(let ([idx
(if (fixnum? next)
next
(get-bucket-index next))])
(let ([fst ($vector-ref vec idx)])
(cond
[(eq? fst b)
($vector-set! vec idx next)]
[else
(replace! fst b next)])))
;;; set next to be #f, denoting, not in table
($set-tcbucket-next! b #f))))
(define (get-bucket h x)
(let ([pv (pointer-value x)]
[vec (hasht-vec h)])
(let ([ih (inthash pv)])
(let ([idx ($fxlogand ih ($fx- ($vector-length vec) 1))])
(let ([b ($vector-ref vec idx)])
(or (direct-lookup x b)
(rehash-lookup h (hasht-tc h) x)))))))
(define (get-hash h x v)
(cond
[(get-bucket h x) =>
(lambda (b) ($tcbucket-val b))]
[else v]))
(define (in-hash? h x)
(and (get-bucket h x) #t))
(define (del-hash h x)
(cond
[(get-bucket h x) => (lambda (b) (unlink! h b))]))
(define put-hash!
(lambda (h x v)
(let ([pv (pointer-value x)]
[vec (hasht-vec h)])
(let ([ih (inthash pv)])
(let ([idx ($fxlogand ih ($fx- ($vector-length vec) 1))])
(let ([b ($vector-ref vec idx)])
(cond
[(or (direct-lookup x b) (rehash-lookup h (hasht-tc h) x))
=>
(lambda (b)
($set-tcbucket-val! b v)
(void))]
[else
(let ([bucket
($make-tcbucket (hasht-tc h) x v ($vector-ref vec idx))])
(if ($fx= (pointer-value x) pv)
($vector-set! vec idx bucket)
(let* ([ih (inthash (pointer-value x))]
[idx
($fxlogand ih ($fx- ($vector-length vec) 1))])
($set-tcbucket-next! bucket ($vector-ref vec idx))
($vector-set! vec idx bucket))))
(let ([ct (hasht-count h)])
(set-hasht-count! h ($fxadd1 ct))
(when ($fx> ct ($vector-length vec))
(enlarge-table h)))])))))))
(define (update-hash! h x proc default)
(cond
[(get-bucket h x) =>
(lambda (b) ($set-tcbucket-val! b (proc ($tcbucket-val b))))]
[else (put-hash! h x (proc default))]))
(define insert-b
(lambda (b vec mask)
(let* ([x ($tcbucket-key b)]
[pv (pointer-value x)]
[ih (inthash pv)]
[idx ($fxlogand ih mask)]
[next ($tcbucket-next b)])
($set-tcbucket-next! b ($vector-ref vec idx))
($vector-set! vec idx b)
(unless (fixnum? next)
(insert-b next vec mask)))))
(define move-all
(lambda (vec1 i n vec2 mask)
(unless ($fx= i n)
(let ([b ($vector-ref vec1 i)])
(unless (fixnum? b)
(insert-b b vec2 mask))
(move-all vec1 ($fxadd1 i) n vec2 mask)))))
(define enlarge-table
(lambda (h)
(let* ([vec1 (hasht-vec h)]
[n1 ($vector-length vec1)]
[n2 ($fxsll n1 1)]
[vec2 (make-base-vec n2)])
(move-all vec1 0 n1 vec2 ($fx- n2 1))
(set-hasht-vec! h vec2))))
(define init-vec
(lambda (v i n)
(if ($fx= i n)
v
(begin
($vector-set! v i i)
(init-vec v ($fxadd1 i) n)))))
(define make-base-vec
(lambda (n)
(init-vec (make-vector n) 0 n)))
(define (clear-hash! h)
(let ([v (hasht-vec h)])
(init-vec v 0 (vector-length v)))
(set-hasht-tc! h
(let ([x (cons #f #f)])
(cons x x)))
(set-hasht-count! h 0))
(define (get-keys h)
(let ([v (hasht-vec h)] [n (hasht-count h)])
(let ([kv (make-vector n)])
(let f ([i ($fxsub1 n)] [j ($fxsub1 (vector-length v))] [kv kv] [v v])
(cond
[($fx= i -1) kv]
[else
(let ([b ($vector-ref v j)])
(if (fixnum? b)
(f i ($fxsub1 j) kv v)
(f (let f ([i i] [b b] [kv kv])
($vector-set! kv i ($tcbucket-key b))
(let ([b ($tcbucket-next b)]
[i ($fxsub1 i)])
(cond
[(fixnum? b) i]
[else (f i b kv)])))
($fxsub1 j) kv v)))])))))
;;; public interface
(define (hashtable? x) (hasht? x))
(define make-eq-hashtable
(case-lambda
[()
(let ([x (cons #f #f)])
(let ([tc (cons x x)])
(make-hasht (make-base-vec 32) 0 tc #t)))]
[(k)
(if (and (or (fixnum? k) (bignum? k))
(>= k 0))
(make-eq-hashtable)
(error 'make-eq-hashtable
"invalid initial capacity" k))]))
(define hashtable-ref
(lambda (h x v)
(if (hasht? h)
(get-hash h x v)
(error 'hashtable-ref "not a hash table" h))))
(define hashtable-contains?
(lambda (h x)
(if (hasht? h)
(in-hash? h x)
(error 'hashtable-contains? "not a hash table" h))))
(define hashtable-set!
(lambda (h x v)
(if (hasht? h)
(if (hasht-mutable? h)
(put-hash! h x v)
(error 'hashtable-set! "hashtable is immutable" h))
(error 'hashtable-set! "not a hash table" h))))
(define hashtable-update!
(lambda (h x proc default)
(if (hasht? h)
(if (hasht-mutable? h)
(if (procedure? proc)
(update-hash! h x proc default)
(error 'hashtable-update! "not a procedure" proc))
(error 'hashtable-update! "hashtable is immutable" h))
(error 'hashtable-update! "not a hash table" h))))
(define hashtable-size
(lambda (h)
(if (hasht? h)
(hasht-count h)
(error 'hashtable-size "not a hash table" h))))
(define hashtable-delete!
(lambda (h x)
;;; FIXME: should shrink table if number of keys drops below
;;; (sqrt (vector-length (hasht-vec h)))
(if (hasht? h)
(if (hasht-mutable? h)
(del-hash h x)
(error 'hashtable-delete! "hashtable is immutable" h))
(error 'hashtable-delete! "not a hash table" h))))
(define (hashtable-keys h)
(if (hasht? h)
(get-keys h)
(error 'hashtable-keys "not a hash table" h)))
(define (hashtable-mutable? h)
(if (hasht? h)
(hasht-mutable? h)
(error 'hashtable-mutable? "not a hash table" h)))
(define (hashtable-clear! h)
(if (hasht? h)
(if (hasht-mutable? h)
(clear-hash! h)
(error 'hashtable-clear! "hashtable is immutable" h))
(error 'hashtable-clear! "not a hash table" h)))
)