sunterlib/s48/meta-gc/gc.scm

71 lines
2.0 KiB
Scheme

;; Copyright (C) Johan Ceuppens 2013
;;
;; This program is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 2 of the License, or
;; (at your option) any later version.
;;
;; 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/>.
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; One chunk per memory allocation, can be used in meta-gc.scm API
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(define (make-gc)
(let ((*heap '())
(*null '())
(*max-datasize 1024)
(*datasize 0)
(*dynamic-data '())
)
(define (malloc)
(add-to-heap! 1)
)
(define (calloc nchunks)
(add-to-heap! nchunks)
)
;; private procedures
(define (get-heap) *heap)
;; data is a string
(define (get-data-size d) (string-length d))
(define (generate-error msg)
(cond ((eq? msg 'memory-exhausted)
(display "memory exhausted")(newline))
))
(define (add-to-heap! n)
(set! *heap (append (get-heap) (list (make-chunk)))))
(define (make-chunk)
(cons 'chunk *null))
(define (set-data! chunk data)
(set-cdr! chunk data))
(define (set-chunk-data! chunk)
(set! *datasize (+ *datasize (get-data-size chunk)))
(if (> *datasize *max-datasize)
(generate-error 'memory-exhausted)
;; The data is dynamically bound in this actor
(set-data! chunk *dynamic-data)
))
(define (dispatch msg)
(cond ((eq? msg 'malloc) malloc)
((eq? msg 'calloc) calloc)
(else (display "make-gc : message not understood : ")(display msg)(newline))
))
dispatch))