#| -*-Scheme-*-

$Id: prop1d.scm,v 14.10 2007/01/05 21:19:28 cph Exp $

Copyright (C) 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994,
    1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
    2006, 2007 Massachusetts Institute of Technology

This file is part of MIT/GNU Scheme.

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it under the terms of the GNU General Public License as published by
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your option) any later version.

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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
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|#

;;;; One Dimensional Property Tables
;;; package: (runtime 1d-property)

(declare (usual-integrations))

(define (initialize-package!)
  (set! population-of-1d-tables (make-population))
  (add-secondary-gc-daemon! gc-1d-tables!))

(define (initialize-unparser!)
  (unparser/set-tagged-pair-method! 1d-table-tag
				    (standard-unparser-method '1D-TABLE #f)))

(define population-of-1d-tables)

(define (gc-1d-tables!)
  (map-over-population! population-of-1d-tables 1d-table/clean!))

(define (make-1d-table)
  (let ((table (list 1d-table-tag)))
    (add-to-population! population-of-1d-tables table)
    table))

(define (1d-table? object)
  (and (pair? object)
       (eq? (car object) 1d-table-tag)))

(define 1d-table-tag
  "1D table")

(define false-key
  "false key")

(define-integrable (weak-cons car cdr)
  (system-pair-cons (ucode-type weak-cons) car cdr))

(define (weak-assq key table)
  (let loop ((previous table) (alist (cdr table)))
    (and (not (null? alist))
	 (let ((entry (car alist))
	       (next (cdr alist)))
	   (let ((key* (system-pair-car entry)))
	     (cond ((not key*)
		    (set-cdr! previous next)
		    (loop previous next))
		   ((eq? key* key)
		    entry)
		   (else
		    (loop alist next))))))))

(define (1d-table/get table key default)
  (let ((entry (weak-assq (or key false-key) table)))
    (if entry
	(system-pair-cdr entry)
	default)))

(define (1d-table/lookup table key if-found if-not-found)
  (let ((entry (weak-assq (or key false-key) table)))
    (if entry
	(if-found (system-pair-cdr entry))
	(if-not-found))))

(define (1d-table/put! table key value)
  (let ((key (or key false-key)))
    (let ((entry (weak-assq key table)))
      (if entry
	  (system-pair-set-cdr! entry value)
	  (set-cdr! table
		    (cons (weak-cons key value)
			  (cdr table))))
      unspecific)))

(define (1d-table/remove! table key)
  (let ((key (or key false-key)))
    (let loop ((previous table) (alist (cdr table)))
      (if (not (null? alist))
	  (let ((key* (system-pair-car (car alist)))
		(next (cdr alist)))
	    (loop (if (or (not key*) (eq? key* key))
		      ;; Might as well clean whole list.
		      (begin
			(set-cdr! previous next)
			previous)
		      alist)
		  next))))))

(define (1d-table/clean! table)
  (let loop ((previous table) (alist (cdr table)))
    (if (not (null? alist))
	(let ((next (cdr alist)))
	  (loop (if (system-pair-car (car alist))
		    alist
		    (begin
		      (set-cdr! previous next)
		      previous))
		next)))))

(define (1d-table/alist table)
  (let loop ((previous table) (alist (cdr table)) (result '()))
    (if (null? alist)
	result
	(let ((entry (car alist))
	      (next (cdr alist)))
	  (let ((key (system-pair-car entry)))
	    (if (not key)
		(begin
		  (set-cdr! previous next)
		  (loop previous next result))
		(loop alist
		      next
		      (cons (cons (and (not (eq? key false-key)) key)
				  (system-pair-cdr entry))
			    result))))))))

(define (1d-table/for-each proc table)
  (let loop ((previous table) (alist (cdr table)))
    (if (not (null? alist))
	(let ((entry (car alist))
	      (next (cdr alist)))
	  (let ((key (system-pair-car entry)))
	    (if key
		(begin
		  (proc (and (not (eq? key false-key)) key)
			(system-pair-cdr entry))
		  (loop alist next))
		(begin
		  (set-cdr! previous next)
		  (loop previous next))))))))