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|
;;;; -*- Mode: Lisp; Syntax: ANSI-Common-Lisp; Base: 10 -*-
;;;; *************************************************************************
;;;; FILE IDENTIFICATION
;;;;
;;;; Name: encode.lisp
;;;; Purpose: cl-base64 encoding routines
;;;; Programmer: Kevin M. Rosenberg
;;;; Date Started: Dec 2002
;;;;
;;;; $Id$
;;;;
;;;; This file implements the Base64 transfer encoding algorithm as
;;;; defined in RFC 1521 by Borensten & Freed, September 1993.
;;;; See: http://www.ietf.org/rfc/rfc1521.txt
;;;;
;;;; Based on initial public domain code by Juri Pakaste <juri@iki.fi>
;;;;
;;;; Copyright 2002-2003 Kevin M. Rosenberg
;;;; Permission to use with BSD-style license included in the COPYING file
;;;; *************************************************************************
;;;; Extended by Kevin M. Rosenberg <kevin@rosenberg.net>:
;;;; - .asd file
;;;; - numerous speed optimizations
;;;; - conversion to and from integers
;;;; - Renamed functions now that supporting integer conversions
;;;; - URI-compatible encoding using :uri key
;;;;
;;;; $Id$
(in-package #:cl-base64)
(defun round-next-multiple (x n)
"Round x up to the next highest multiple of n."
(declare (fixnum n)
(optimize (speed 3) (safety 1) (space 0)))
(let ((remainder (mod x n)))
(declare (fixnum remainder))
(if (zerop remainder)
x
(the fixnum (+ x (the fixnum (- n remainder)))))))
(defmacro def-*-to-base64-* (input-type output-type)
`(defun ,(intern (concatenate 'string (symbol-name input-type)
(symbol-name :-to-base64-)
(symbol-name output-type)))
(input
,@(when (eq output-type :stream)
'(output))
&key (uri nil) (columns 0))
"Encode a string array to base64. If columns is > 0, designates
maximum number of columns in a line and the string will be terminated
with a #\Newline."
(declare ,@(case input-type
(:string
'((string input)))
(:usb8-array
'((type (array (unsigned-byte 8) (*)) input))))
(fixnum columns)
(optimize (speed 3) (safety 1) (space 0)))
(let ((pad (if uri *uri-pad-char* *pad-char*))
(encode-table (if uri *uri-encode-table* *encode-table*)))
(declare (simple-string encode-table)
(character pad))
(let* ((string-length (length input))
(complete-group-count (truncate string-length 3))
(remainder (nth-value 1 (truncate string-length 3)))
(padded-length (* 4 (truncate (+ string-length 2) 3)))
,@(when (eq output-type :string)
'((num-lines (if (plusp columns)
(truncate (+ padded-length (1- columns)) columns)
0))
(num-breaks (if (plusp num-lines)
(1- num-lines)
0))
(strlen (+ padded-length num-breaks))
(result (make-string strlen))
(ioutput 0)))
(col (if (plusp columns)
0
(the fixnum (1+ padded-length)))))
(declare (fixnum string-length padded-length col
,@(when (eq output-type :string)
'(ioutput)))
,@(when (eq output-type :string)
'((simple-string result))))
(labels ((output-char (ch)
(if (= col columns)
(progn
,@(case output-type
(:stream
'((write-char #\Newline output)))
(:string
'((setf (schar result ioutput) #\Newline)
(incf ioutput))))
(setq col 1))
(incf col))
,@(case output-type
(:stream
'((write-char ch output)))
(:string
'((setf (schar result ioutput) ch)
(incf ioutput)))))
(output-group (svalue chars)
(declare (fixnum svalue chars))
(output-char
(schar encode-table
(the fixnum
(logand #x3f
(the fixnum (ash svalue -18))))))
(output-char
(schar encode-table
(the fixnum
(logand #x3f
(the fixnum (ash svalue -12))))))
(if (> chars 2)
(output-char
(schar encode-table
(the fixnum
(logand #x3f
(the fixnum (ash svalue -6))))))
(output-char pad))
(if (> chars 3)
(output-char
(schar encode-table
(the fixnum
(logand #x3f svalue))))
(output-char pad))))
(do ((igroup 0 (the fixnum (1+ igroup)))
(isource 0 (the fixnum (+ isource 3))))
((= igroup complete-group-count)
(cond
((= remainder 2)
(output-group
(the fixnum
(+
(the fixnum
(ash
,(case input-type
(:string
'(char-code (the character (char input isource))))
(:usb8-array
'(the fixnum (aref input isource))))
16))
(the fixnum
(ash
,(case input-type
(:string
'(char-code (the character (char input
(the fixnum (1+ isource))))))
(:usb8-array
'(the fixnum (aref input (the fixnum
(1+ isource))))))
8))))
3))
((= remainder 1)
(output-group
(the fixnum
(ash
,(case input-type
(:string
'(char-code (the character (char input isource))))
(:usb8-array
'(the fixnum (aref input isource))))
16))
2)))
,(case output-type
(:string
'result)
(:stream
'output)))
(declare (fixnum igroup isource))
(output-group
(the fixnum
(+
(the fixnum
(ash
(the fixnum
,(case input-type
(:string
'(char-code (the character (char input isource))))
(:usb8-array
'(aref input isource))))
16))
(the fixnum
(ash
(the fixnum
,(case input-type
(:string
'(char-code (the character (char input
(the fixnum (1+ isource))))))
(:usb8-array
'(aref input (1+ isource)))))
8))
(the fixnum
,(case input-type
(:string
'(char-code (the character (char input
(the fixnum (+ 2 isource))))))
(:usb8-array
'(aref input (+ 2 isource))))
)))
4)))))))
(def-*-to-base64-* :string :string)
(def-*-to-base64-* :string :stream)
(def-*-to-base64-* :usb8-array :string)
(def-*-to-base64-* :usb8-array :stream)
(defun integer-to-base64-string (input &key (uri nil) (columns 0))
"Encode an integer to base64 format."
(declare (integer input)
(fixnum columns)
(optimize (speed 3) (space 0) (safety 1)))
(let ((pad (if uri *uri-pad-char* *pad-char*))
(encode-table (if uri *uri-encode-table* *encode-table*)))
(declare (simple-string encode-table)
(character pad))
(let* ((input-bits (integer-length input))
(byte-bits (round-next-multiple input-bits 8))
(padded-bits (round-next-multiple byte-bits 6))
(remainder-padding (mod padded-bits 24))
(padding-bits (if (zerop remainder-padding)
0
(- 24 remainder-padding)))
(padding-chars (/ padding-bits 6))
(padded-length (/ (+ padded-bits padding-bits) 6))
(last-line-len (if (plusp columns)
(- padded-length (* columns
(truncate
padded-length columns)))
0))
(num-lines (if (plusp columns)
(truncate (+ padded-length (1- columns)) columns)
0))
(num-breaks (if (plusp num-lines)
(1- num-lines)
0))
(strlen (+ padded-length num-breaks))
(last-char (1- strlen))
(str (make-string strlen))
(col (if (zerop last-line-len)
columns
last-line-len)))
(declare (fixnum padded-length num-lines col last-char
padding-chars last-line-len))
(unless (plusp columns)
(setq col -1)) ;; set to flag to optimize in loop
(dotimes (i padding-chars)
(declare (fixnum i))
(setf (schar str (the fixnum (- last-char i))) pad))
(do* ((strpos (- last-char padding-chars) (1- strpos))
(int (ash input (/ padding-bits 3))))
((minusp strpos)
str)
(declare (fixnum strpos) (integer int))
(cond
((zerop col)
(setf (schar str strpos) #\Newline)
(setq col columns))
(t
(setf (schar str strpos)
(schar encode-table (the fixnum (logand int #x3f))))
(setq int (ash int -6))
(decf col)))))))
(defun integer-to-base64-stream (input stream &key (uri nil) (columns 0))
"Encode an integer to base64 format."
(declare (integer input)
(fixnum columns)
(optimize (speed 3) (space 0) (safety 1)))
(let ((pad (if uri *uri-pad-char* *pad-char*))
(encode-table (if uri *uri-encode-table* *encode-table*)))
(declare (simple-string encode-table)
(character pad))
(let* ((input-bits (integer-length input))
(byte-bits (round-next-multiple input-bits 8))
(padded-bits (round-next-multiple byte-bits 6))
(remainder-padding (mod padded-bits 24))
(padding-bits (if (zerop remainder-padding)
0
(- 24 remainder-padding)))
(padding-chars (/ padding-bits 6))
(padded-length (/ (+ padded-bits padding-bits) 6))
(strlen padded-length)
(nonpad-chars (- strlen padding-chars))
(last-nonpad-char (1- nonpad-chars))
(str (make-string strlen)))
(declare (fixnum padded-length last-nonpad-char))
(do* ((strpos 0 (the fixnum (1+ strpos)))
(int (ash input (/ padding-bits 3)) (ash int -6))
(6bit-value (the fixnum (logand int #x3f))
(the fixnum (logand int #x3f))))
((= strpos nonpad-chars)
(let ((col 0))
(declare (fixnum col))
(dotimes (i nonpad-chars)
(declare (fixnum i))
(write-char (schar str i) stream)
(when (plusp columns)
(incf col)
(when (= col columns)
(write-char #\Newline stream)
(setq col 0))))
(dotimes (ipad padding-chars)
(declare (fixnum ipad))
(write-char pad stream)
(when (plusp columns)
(incf col)
(when (= col columns)
(write-char #\Newline stream)
(setq col 0)))))
stream)
(declare (fixnum 6bit-value strpos)
(integer int))
(setf (schar str (- last-nonpad-char strpos))
(schar encode-table 6bit-value))
))))
|
