#| -*-Scheme-*-

Copyright (C) 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994,
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    2017, 2018, 2019, 2020 Massachusetts Institute of Technology

This file is part of MIT/GNU Scheme.

MIT/GNU Scheme 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.

MIT/GNU Scheme 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 MIT/GNU Scheme; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301,
USA.

|#

;;;; Interface to cryptography libraries
;;; package: (runtime crypto)

(declare (usual-integrations))

;;;; MD5

(define (md5-available?)
  #t)

(define (md5-file filename)
  (call-with-binary-input-file filename
    (port-consumer (ucode-primitive md5-init 0)
		   (ucode-primitive md5-update 4)
		   (ucode-primitive md5-final 1))))

(define (md5-string string #!optional start end)
  (md5-bytevector (string->utf8 string start end)))

(define (md5-bytevector bytes #!optional start end)
  (let ((end (fix:end-index end (bytevector-length bytes) 'md5-bytevector))
	(start (fix:start-index start end 'md5-bytevector))
	(context ((ucode-primitive md5-init 0))))
    ((ucode-primitive md5-update 4) context bytes start end)
    ((ucode-primitive md5-final 1) context)))

(define (port-consumer initialize update finalize)
  (lambda (port)
    (call-with-buffer #x1000
      (lambda (buffer)
	(let ((context (initialize)))
	  (let loop ()
	    (let ((n (read-bytevector! buffer port)))
	      (if (and n (not (eof-object? n)))
		  (begin
		    (update context buffer 0 n)
		    (loop)))))
	  (finalize context))))))

(define (call-with-buffer n procedure)
  (let ((buffer (make-bytevector n)))
    (dynamic-wind
	(lambda ()
	  unspecific)
	(lambda ()
	  (procedure buffer))
	(lambda ()
	  (bytevector-fill! buffer 0)))))

;;;; The mcrypt library

(define mcrypt-linked? #f)

(define (mcrypt-available?)
  (and (plugin-available? "mcrypt")
       (or mcrypt-linked?
	   (begin
	     (load-option 'mcrypt)
	     (mcrypt-link!)
	     #t))))

(define (mcrypt-link!)
  (for-each
    (let ((runtime (->environment '(runtime crypto)))
	  (mcrypt (->environment '(mcrypt))))
      (lambda (name)
	(environment-link-name runtime mcrypt name)))
    mcrypt-names)
  (set! mcrypt-linked? #t))

(define mcrypt-names
  '(mcrypt-algorithm-name
    mcrypt-algorithm-names
    mcrypt-block-algorithm-mode?
    mcrypt-block-algorithm?
    mcrypt-block-mode?
    mcrypt-context?
    mcrypt-decrypt!
    mcrypt-encrypt
    mcrypt-encrypt!
    mcrypt-encrypt-port
    mcrypt-end
    mcrypt-init
    mcrypt-init-vector-size
    mcrypt-key-size
    mcrypt-mode-name
    mcrypt-mode-names
    mcrypt-open-module
    mcrypt-self-test
    mcrypt-supported-key-sizes))

(define mcrypt-algorithm-name)
(define mcrypt-algorithm-names)
(define mcrypt-block-algorithm-mode?)
(define mcrypt-block-algorithm?)
(define mcrypt-block-mode?)
(define mcrypt-context?)
(define mcrypt-decrypt!)
(define mcrypt-encrypt)
(define mcrypt-encrypt!)
(define mcrypt-encrypt-port)
(define mcrypt-end)
(define mcrypt-init)
(define mcrypt-init-vector-size)
(define mcrypt-key-size)
(define mcrypt-mode-name)
(define mcrypt-mode-names)
(define mcrypt-open-module)
(define mcrypt-self-test)
(define mcrypt-supported-key-sizes)