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0f2d19dd JB |
1 | ;;; installed-scm-file |
2 | ||
cd5fea8d | 3 | ;;;; Copyright (C) 1995, 1996, 1998, 2001, 2003, 2006 Free Software Foundation, Inc. |
0f2d19dd | 4 | ;;;; |
73be1d9e MV |
5 | ;;;; This library is free software; you can redistribute it and/or |
6 | ;;;; modify it under the terms of the GNU Lesser General Public | |
7 | ;;;; License as published by the Free Software Foundation; either | |
53befeb7 | 8 | ;;;; version 3 of the License, or (at your option) any later version. |
0f2d19dd | 9 | ;;;; |
73be1d9e | 10 | ;;;; This library is distributed in the hope that it will be useful, |
0f2d19dd | 11 | ;;;; but WITHOUT ANY WARRANTY; without even the implied warranty of |
73be1d9e MV |
12 | ;;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
13 | ;;;; Lesser General Public License for more details. | |
0f2d19dd | 14 | ;;;; |
73be1d9e MV |
15 | ;;;; You should have received a copy of the GNU Lesser General Public |
16 | ;;;; License along with this library; if not, write to the Free Software | |
92205699 | 17 | ;;;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
0f2d19dd JB |
18 | ;;;; |
19 | ||
20 | \f | |
1a179b03 MD |
21 | (define-module (ice-9 hcons) |
22 | :export (hashq-cons-hash hashq-cons-assoc hashq-cons-get-handle | |
23 | hashq-cons-create-handle! hashq-cons-ref hashq-cons-set! hashq-cons | |
24 | hashq-conser make-gc-buffer)) | |
0f2d19dd JB |
25 | |
26 | \f | |
27 | ;;; {Eq? hash-consing} | |
28 | ;;; | |
29 | ;;; A hash conser maintains a private universe of pairs s.t. if | |
30 | ;;; two cons calls pass eq? arguments, the pairs returned are eq?. | |
31 | ;;; | |
32 | ;;; A hash conser does not contribute life to the pairs it returns. | |
33 | ;;; | |
34 | ||
1a179b03 | 35 | (define (hashq-cons-hash pair n) |
0f2d19dd JB |
36 | (modulo (logxor (hashq (car pair) 4194303) |
37 | (hashq (cdr pair) 4194303)) | |
38 | n)) | |
39 | ||
1a179b03 | 40 | (define (hashq-cons-assoc key l) |
048a208e JB |
41 | (and (not (null? l)) |
42 | (or (and (pair? l) ; If not a pair, use its cdr? | |
43 | (pair? (car l)) | |
44 | (pair? (caar l)) | |
45 | (eq? (car key) (caaar l)) | |
46 | (eq? (cdr key) (cdaar l)) | |
47 | (car l)) | |
48 | (hashq-cons-assoc key (cdr l))))) | |
0f2d19dd | 49 | |
1a179b03 | 50 | (define (hashq-cons-get-handle table key) |
f70b2b1e | 51 | (hashx-get-handle hashq-cons-hash hashq-cons-assoc table key)) |
0f2d19dd | 52 | |
1a179b03 | 53 | (define (hashq-cons-create-handle! table key init) |
0f2d19dd JB |
54 | (hashx-create-handle! hashq-cons-hash hashq-cons-assoc table key init)) |
55 | ||
1a179b03 | 56 | (define (hashq-cons-ref table key) |
0f2d19dd JB |
57 | (hashx-ref hashq-cons-hash hashq-cons-assoc table key #f)) |
58 | ||
1a179b03 | 59 | (define (hashq-cons-set! table key val) |
0f2d19dd JB |
60 | (hashx-set! hashq-cons-hash hashq-cons-assoc table key val)) |
61 | ||
1a179b03 | 62 | (define (hashq-cons table a d) |
0f2d19dd JB |
63 | (car (hashq-cons-create-handle! table (cons a d) #f))) |
64 | ||
1a179b03 | 65 | (define (hashq-conser hash-tab-or-size) |
0f2d19dd JB |
66 | (let ((table (if (vector? hash-tab-or-size) |
67 | hash-tab-or-size | |
68 | (make-doubly-weak-hash-table hash-tab-or-size)))) | |
69 | (lambda (a d) (hashq-cons table a d)))) | |
70 | ||
71 | ||
72 | \f | |
73 | ||
1a179b03 | 74 | (define (make-gc-buffer n) |
0f2d19dd JB |
75 | (let ((ring (make-list n #f))) |
76 | (append! ring ring) | |
77 | (lambda (next) | |
78 | (set-car! ring next) | |
79 | (set! ring (cdr ring)) | |
80 | next))) |