110 lines
3.3 KiB
Scheme
110 lines
3.3 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.sort)
|
|
(export list-sort vector-sort vector-sort!)
|
|
(import
|
|
(ikarus system $fx)
|
|
(except (ikarus) list-sort vector-sort vector-sort!))
|
|
|
|
(module (sort-tail)
|
|
(define (merge1 <? a1 ls1 ls2)
|
|
(cond
|
|
[(null? ls2) ls1]
|
|
[else
|
|
(let ([a2 (car ls2)])
|
|
(cond
|
|
[(<? a2 a1)
|
|
(cons a2 (merge1 <? a1 ls1 (cdr ls2)))]
|
|
[else
|
|
(cons a1 (merge2 <? a2 (cdr ls1) ls2))]))]))
|
|
|
|
(define (merge2 <? a2 ls1 ls2)
|
|
(cond
|
|
[(null? ls1) ls2]
|
|
[else
|
|
(let ([a1 (car ls1)])
|
|
(cond
|
|
[(<? a2 a1)
|
|
(cons a2 (merge1 <? a1 ls1 (cdr ls2)))]
|
|
[else
|
|
(cons a1 (merge2 <? a2 (cdr ls1) ls2))]))]))
|
|
|
|
(define (merge <? ls1 ls2)
|
|
(cond
|
|
[(null? ls2) ls1]
|
|
[else
|
|
(let ([a1 (car ls1)] [a2 (car ls2)])
|
|
(cond
|
|
[(<? a2 a1)
|
|
(cons a2 (merge1 <? a1 ls1 (cdr ls2)))]
|
|
[else
|
|
(cons a1 (merge2 <? a2 (cdr ls1) ls2))]))]))
|
|
|
|
(define (sort-head <? ls n)
|
|
(cond
|
|
[($fx= n 0) (values '() ls)]
|
|
[($fx= n 1)
|
|
(values (cons (car ls) '()) (cdr ls))]
|
|
[else
|
|
(let-values ([(sorted-head tail)
|
|
(sort-head <? ls ($fxsra n 1))])
|
|
(let-values ([(sorted-tail tail)
|
|
(sort-head <? tail ($fx- n ($fxsra n 1)))])
|
|
(values (merge <? sorted-head sorted-tail) tail)))]))
|
|
|
|
(define (sort-tail <? ls n)
|
|
(cond
|
|
[($fx<= n 1) ls]
|
|
[else
|
|
(let-values ([(sorted-head tail)
|
|
(sort-head <? ls ($fxsra n 1))])
|
|
(merge <? sorted-head
|
|
(sort-tail <? tail ($fx- n ($fxsra n 1)))))])))
|
|
|
|
(define (list-sort <? ls)
|
|
(unless (procedure? <?)
|
|
(error 'list-sort "not a procedure" <?))
|
|
(sort-tail <? ls (length ls)))
|
|
|
|
|
|
|
|
(define (vector-sort <? v)
|
|
;;; FIXME: improve
|
|
(unless (procedure? <?)
|
|
(error 'vector-sort "not a procedure" <?))
|
|
(unless (vector? v)
|
|
(error 'vector-sort "not a vector" v))
|
|
(list->vector
|
|
(sort-tail <? (vector->list v) (vector-length v))))
|
|
|
|
(define (vector-sort! <? v)
|
|
(import (ikarus system $vectors))
|
|
(import (ikarus system $pairs))
|
|
(unless (procedure? <?)
|
|
(error 'vector-sort! "not a procedure" <?))
|
|
(unless (vector? v)
|
|
(error 'vector-sort! "not a vector" v))
|
|
(let f ([i 0] [v v]
|
|
[ls (sort-tail <? (vector->list v) (vector-length v))])
|
|
(unless (null? ls)
|
|
($vector-set! v i ($car ls))
|
|
(f ($fx+ i 1) v ($cdr ls)))))
|
|
|
|
)
|
|
|
|
|