;;;;
;;;; srfi-69.stk	-- Basic Hash-tables Implementation
;;;;
;;;; Copyright © 2005-2007 Erick Gallesio - I3S-CNRS/ESSI <eg@essi.fr>
;;;;
;;;;
;;;; 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, write to the Free Software
;;;; Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
;;;; USA.
;;;;
;;;;           Author: Erick Gallesio [eg@essi.fr]
;;;;    Creation date: 27-Oct-2005 23:09 (eg)
;;;; Last file update: 10-Apr-2007 19:13 (eg)
;;;;

(define *%default-hash-size* (expt 2 29))

;; ======================================================================
;; The SRFI-69 hash functions
;; They are not defined by default since
;;    - they are not prefixed by hash-table
;;    - string-hash conflicts with SRFI-13
;;    - the bound default parameter is a weird idea
;;    - string-hash is useless with STklos standard hash-table-hash function

(define (hash obj :optional (bound *%default-hash-size*))
  (modulo (hash-table-hash obj) bound))

(define (string-hash obj :optional (bound *%default-hash-size*))
  (if (string? obj)
      (modulo (hash-table-hash obj) bound)
      (error "bad string ~S" obj)))

(define (string-ci-hash obj :optional (bound *%default-hash-size*))
  (if (string? obj)
      (modulo (hash-table-hash (string-downcase obj)) bound)
      (error "bad string ~S" obj)))

(define (hash-by-identity obj :optional (bound *%default-hash-size*))
  (modulo (address-of obj) bound))

;; ======================================================================
;; Redefine make-hash-table and alist->hash-table to use equal? instead of
;; eq? as default comparison function

(define %old-make-hash-table make-hash-table)
(define %old-alist->hash-table alist->hash-table)

(define (make-hash-table :optional (comp equal?) (hash hash))
  (%old-make-hash-table comp hash))

;; hash-table-for-each is called hash-table-walk in SRFI-69
(define hash-table-walk hash-table-for-each) ;; Name used in srfi69


(provide "srfi-69")