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emacs/lisp/sha1.el
Stefan Monnier d008105801 (sha1-string-external): Use set-buffer-multibyte rather than 
setting default-enable-multibyte-characters.
2008-03-12 20:48:46 +00:00

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;;; sha1.el --- SHA1 Secure Hash Algorithm in Emacs-Lisp
;; Copyright (C) 1999, 2001, 2002, 2003, 2004,
;; 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
;; Author: Shuhei KOBAYASHI <shuhei@aqua.ocn.ne.jp>
;; Keywords: SHA1, FIPS 180-1
;; This file is part of GNU Emacs.
;; GNU Emacs 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 3, or (at your option)
;; any later version.
;; GNU Emacs 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 GNU Emacs; see the file COPYING. If not, write to the
;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
;; Boston, MA 02110-1301, USA.
;;; Commentary:
;; This program is implemented from the definition of SHA-1 in FIPS PUB
;; 180-1 (Federal Information Processing Standards Publication 180-1),
;; "Announcing the Standard for SECURE HASH STANDARD".
;; <URL:http://www.itl.nist.gov/div897/pubs/fip180-1.htm>
;; (EXCEPTION; two optimizations taken from GnuPG/cipher/sha1.c)
;;
;; Test cases from FIPS PUB 180-1.
;;
;; (sha1 "abc")
;; => a9993e364706816aba3e25717850c26c9cd0d89d
;;
;; (sha1 "abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq")
;; => 84983e441c3bd26ebaae4aa1f95129e5e54670f1
;;
;; (sha1 (make-string 1000000 ?a))
;; => 34aa973cd4c4daa4f61eeb2bdbad27316534016f
;;
;; BUGS:
;; * It is assumed that length of input string is less than 2^29 bytes.
;; * It is caller's responsibility to make string (or region) unibyte.
;;
;; TODO:
;; * Rewrite from scratch!
;; This version is much faster than Keiichi Suzuki's another sha1.el,
;; but it is too dirty.
;;; Code:
(require 'hex-util)
;;;
;;; external SHA1 function.
;;;
(defgroup sha1 nil
"Elisp interface for SHA1 hash computation."
:version "22.1"
:group 'extensions)
(defcustom sha1-maximum-internal-length 500
"*Maximum length of message to use Lisp version of SHA1 function.
If message is longer than this, `sha1-program' is used instead.
If this variable is set to 0, use external program only.
If this variable is set to nil, use internal function only."
:type 'integer
:group 'sha1)
(defcustom sha1-program '("sha1sum")
"*Name of program to compute SHA1.
It must be a string \(program name\) or list of strings \(name and its args\)."
:type '(repeat string)
:group 'sha1)
(defcustom sha1-use-external (condition-case ()
(executable-find (car sha1-program))
(error))
"*Use external SHA1 program.
If this variable is set to nil, use internal function only."
:type 'boolean
:group 'sha1)
(defun sha1-string-external (string &optional binary)
(let (prog args digest)
(if (consp sha1-program)
(setq prog (car sha1-program)
args (cdr sha1-program))
(setq prog sha1-program
args nil))
(with-temp-buffer
(set-buffer-multibyte nil)
(insert string)
(apply (function call-process-region)
(point-min) (point-max)
prog t t nil args)
;; SHA1 is 40 bytes long in hexadecimal form.
(setq digest (buffer-substring (point-min)(+ (point-min) 40))))
(if binary
(decode-hex-string digest)
digest)))
(defun sha1-region-external (beg end &optional binary)
(sha1-string-external (buffer-substring-no-properties beg end) binary))
;;;
;;; internal SHA1 function.
;;;
(eval-when-compile
;; optional second arg of string-to-number is new in v20.
(defconst sha1-K0-high 23170) ; (string-to-number "5A82" 16)
(defconst sha1-K0-low 31129) ; (string-to-number "7999" 16)
(defconst sha1-K1-high 28377) ; (string-to-number "6ED9" 16)
(defconst sha1-K1-low 60321) ; (string-to-number "EBA1" 16)
(defconst sha1-K2-high 36635) ; (string-to-number "8F1B" 16)
(defconst sha1-K2-low 48348) ; (string-to-number "BCDC" 16)
(defconst sha1-K3-high 51810) ; (string-to-number "CA62" 16)
(defconst sha1-K3-low 49622) ; (string-to-number "C1D6" 16)
;; original definition of sha1-F0.
;; (defmacro sha1-F0 (B C D)
;; (` (logior (logand (, B) (, C))
;; (logand (lognot (, B)) (, D)))))
;; a little optimization from GnuPG/cipher/sha1.c.
(defmacro sha1-F0 (B C D)
`(logxor ,D (logand ,B (logxor ,C ,D))))
(defmacro sha1-F1 (B C D)
`(logxor ,B ,C ,D))
;; original definition of sha1-F2.
;; (defmacro sha1-F2 (B C D)
;; (` (logior (logand (, B) (, C))
;; (logand (, B) (, D))
;; (logand (, C) (, D)))))
;; a little optimization from GnuPG/cipher/sha1.c.
(defmacro sha1-F2 (B C D)
`(logior (logand ,B ,C)
(logand ,D (logior ,B ,C))))
(defmacro sha1-F3 (B C D)
`(logxor ,B ,C ,D))
(defmacro sha1-S1 (W-high W-low)
`(let ((W-high ,W-high)
(W-low ,W-low))
(setq S1W-high (+ (% (* W-high 2) 65536)
(/ W-low ,(/ 65536 2))))
(setq S1W-low (+ (/ W-high ,(/ 65536 2))
(% (* W-low 2) 65536)))))
(defmacro sha1-S5 (A-high A-low)
`(progn
(setq S5A-high (+ (% (* ,A-high 32) 65536)
(/ ,A-low ,(/ 65536 32))))
(setq S5A-low (+ (/ ,A-high ,(/ 65536 32))
(% (* ,A-low 32) 65536)))))
(defmacro sha1-S30 (B-high B-low)
`(progn
(setq S30B-high (+ (/ ,B-high 4)
(* (% ,B-low 4) ,(/ 65536 4))))
(setq S30B-low (+ (/ ,B-low 4)
(* (% ,B-high 4) ,(/ 65536 4))))))
(defmacro sha1-OP (round)
`(progn
(sha1-S5 sha1-A-high sha1-A-low)
(sha1-S30 sha1-B-high sha1-B-low)
(setq sha1-A-low (+ (,(intern (format "sha1-F%d" round))
sha1-B-low sha1-C-low sha1-D-low)
sha1-E-low
,(symbol-value
(intern (format "sha1-K%d-low" round)))
(aref block-low idx)
(progn
(setq sha1-E-low sha1-D-low)
(setq sha1-D-low sha1-C-low)
(setq sha1-C-low S30B-low)
(setq sha1-B-low sha1-A-low)
S5A-low)))
(setq carry (/ sha1-A-low 65536))
(setq sha1-A-low (% sha1-A-low 65536))
(setq sha1-A-high (% (+ (,(intern (format "sha1-F%d" round))
sha1-B-high sha1-C-high sha1-D-high)
sha1-E-high
,(symbol-value
(intern (format "sha1-K%d-high" round)))
(aref block-high idx)
(progn
(setq sha1-E-high sha1-D-high)
(setq sha1-D-high sha1-C-high)
(setq sha1-C-high S30B-high)
(setq sha1-B-high sha1-A-high)
S5A-high)
carry)
65536))))
(defmacro sha1-add-to-H (H X)
`(progn
(setq ,(intern (format "sha1-%s-low" H))
(+ ,(intern (format "sha1-%s-low" H))
,(intern (format "sha1-%s-low" X))))
(setq carry (/ ,(intern (format "sha1-%s-low" H)) 65536))
(setq ,(intern (format "sha1-%s-low" H))
(% ,(intern (format "sha1-%s-low" H)) 65536))
(setq ,(intern (format "sha1-%s-high" H))
(% (+ ,(intern (format "sha1-%s-high" H))
,(intern (format "sha1-%s-high" X))
carry)
65536))))
)
;;; buffers (H0 H1 H2 H3 H4).
(defvar sha1-H0-high)
(defvar sha1-H0-low)
(defvar sha1-H1-high)
(defvar sha1-H1-low)
(defvar sha1-H2-high)
(defvar sha1-H2-low)
(defvar sha1-H3-high)
(defvar sha1-H3-low)
(defvar sha1-H4-high)
(defvar sha1-H4-low)
(defun sha1-block (block-high block-low)
(let (;; step (c) --- initialize buffers (A B C D E).
(sha1-A-high sha1-H0-high) (sha1-A-low sha1-H0-low)
(sha1-B-high sha1-H1-high) (sha1-B-low sha1-H1-low)
(sha1-C-high sha1-H2-high) (sha1-C-low sha1-H2-low)
(sha1-D-high sha1-H3-high) (sha1-D-low sha1-H3-low)
(sha1-E-high sha1-H4-high) (sha1-E-low sha1-H4-low)
(idx 16))
;; step (b).
(let (;; temporary variables used in sha1-S1 macro.
S1W-high S1W-low)
(while (< idx 80)
(sha1-S1 (logxor (aref block-high (- idx 3))
(aref block-high (- idx 8))
(aref block-high (- idx 14))
(aref block-high (- idx 16)))
(logxor (aref block-low (- idx 3))
(aref block-low (- idx 8))
(aref block-low (- idx 14))
(aref block-low (- idx 16))))
(aset block-high idx S1W-high)
(aset block-low idx S1W-low)
(setq idx (1+ idx))))
;; step (d).
(setq idx 0)
(let (;; temporary variables used in sha1-OP macro.
S5A-high S5A-low S30B-high S30B-low carry)
(while (< idx 20) (sha1-OP 0) (setq idx (1+ idx)))
(while (< idx 40) (sha1-OP 1) (setq idx (1+ idx)))
(while (< idx 60) (sha1-OP 2) (setq idx (1+ idx)))
(while (< idx 80) (sha1-OP 3) (setq idx (1+ idx))))
;; step (e).
(let (;; temporary variables used in sha1-add-to-H macro.
carry)
(sha1-add-to-H H0 A)
(sha1-add-to-H H1 B)
(sha1-add-to-H H2 C)
(sha1-add-to-H H3 D)
(sha1-add-to-H H4 E))))
(defun sha1-binary (string)
"Return the SHA1 of STRING in binary form."
(let (;; prepare buffers for a block. byte-length of block is 64.
;; input block is split into two vectors.
;;
;; input block: 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F ...
;; block-high: +-0-+ +-1-+ +-2-+ +-3-+
;; block-low: +-0-+ +-1-+ +-2-+ +-3-+
;;
;; length of each vector is 80, and elements of each vector are
;; 16bit integers. elements 0x10-0x4F of each vector are
;; assigned later in `sha1-block'.
(block-high (eval-when-compile (make-vector 80 nil)))
(block-low (eval-when-compile (make-vector 80 nil))))
(unwind-protect
(let* (;; byte-length of input string.
(len (length string))
(lim (* (/ len 64) 64))
(rem (% len 4))
(idx 0)(pos 0))
;; initialize buffers (H0 H1 H2 H3 H4).
(setq sha1-H0-high 26437 ; (string-to-number "6745" 16)
sha1-H0-low 8961 ; (string-to-number "2301" 16)
sha1-H1-high 61389 ; (string-to-number "EFCD" 16)
sha1-H1-low 43913 ; (string-to-number "AB89" 16)
sha1-H2-high 39098 ; (string-to-number "98BA" 16)
sha1-H2-low 56574 ; (string-to-number "DCFE" 16)
sha1-H3-high 4146 ; (string-to-number "1032" 16)
sha1-H3-low 21622 ; (string-to-number "5476" 16)
sha1-H4-high 50130 ; (string-to-number "C3D2" 16)
sha1-H4-low 57840) ; (string-to-number "E1F0" 16)
;; loop for each 64 bytes block.
(while (< pos lim)
;; step (a).
(setq idx 0)
(while (< idx 16)
(aset block-high idx (+ (* (aref string pos) 256)
(aref string (1+ pos))))
(setq pos (+ pos 2))
(aset block-low idx (+ (* (aref string pos) 256)
(aref string (1+ pos))))
(setq pos (+ pos 2))
(setq idx (1+ idx)))
(sha1-block block-high block-low))
;; last block.
(if (prog1
(< (- len lim) 56)
(setq lim (- len rem))
(setq idx 0)
(while (< pos lim)
(aset block-high idx (+ (* (aref string pos) 256)
(aref string (1+ pos))))
(setq pos (+ pos 2))
(aset block-low idx (+ (* (aref string pos) 256)
(aref string (1+ pos))))
(setq pos (+ pos 2))
(setq idx (1+ idx)))
;; this is the last (at most) 32bit word.
(cond
((= rem 3)
(aset block-high idx (+ (* (aref string pos) 256)
(aref string (1+ pos))))
(setq pos (+ pos 2))
(aset block-low idx (+ (* (aref string pos) 256)
128)))
((= rem 2)
(aset block-high idx (+ (* (aref string pos) 256)
(aref string (1+ pos))))
(aset block-low idx 32768))
((= rem 1)
(aset block-high idx (+ (* (aref string pos) 256)
128))
(aset block-low idx 0))
(t ;; (= rem 0)
(aset block-high idx 32768)
(aset block-low idx 0)))
(setq idx (1+ idx))
(while (< idx 16)
(aset block-high idx 0)
(aset block-low idx 0)
(setq idx (1+ idx))))
;; last block has enough room to write the length of string.
(progn
;; write bit length of string to last 4 bytes of the block.
(aset block-low 15 (* (% len 8192) 8))
(setq len (/ len 8192))
(aset block-high 15 (% len 65536))
;; XXX: It is not practical to compute SHA1 of
;; such a huge message on emacs.
;; (setq len (/ len 65536)) ; for 64bit emacs.
;; (aset block-low 14 (% len 65536))
;; (aset block-high 14 (/ len 65536))
(sha1-block block-high block-low))
;; need one more block.
(sha1-block block-high block-low)
(fillarray block-high 0)
(fillarray block-low 0)
;; write bit length of string to last 4 bytes of the block.
(aset block-low 15 (* (% len 8192) 8))
(setq len (/ len 8192))
(aset block-high 15 (% len 65536))
;; XXX: It is not practical to compute SHA1 of
;; such a huge message on emacs.
;; (setq len (/ len 65536)) ; for 64bit emacs.
;; (aset block-low 14 (% len 65536))
;; (aset block-high 14 (/ len 65536))
(sha1-block block-high block-low))
;; make output string (in binary form).
(let ((result (make-string 20 0)))
(aset result 0 (/ sha1-H0-high 256))
(aset result 1 (% sha1-H0-high 256))
(aset result 2 (/ sha1-H0-low 256))
(aset result 3 (% sha1-H0-low 256))
(aset result 4 (/ sha1-H1-high 256))
(aset result 5 (% sha1-H1-high 256))
(aset result 6 (/ sha1-H1-low 256))
(aset result 7 (% sha1-H1-low 256))
(aset result 8 (/ sha1-H2-high 256))
(aset result 9 (% sha1-H2-high 256))
(aset result 10 (/ sha1-H2-low 256))
(aset result 11 (% sha1-H2-low 256))
(aset result 12 (/ sha1-H3-high 256))
(aset result 13 (% sha1-H3-high 256))
(aset result 14 (/ sha1-H3-low 256))
(aset result 15 (% sha1-H3-low 256))
(aset result 16 (/ sha1-H4-high 256))
(aset result 17 (% sha1-H4-high 256))
(aset result 18 (/ sha1-H4-low 256))
(aset result 19 (% sha1-H4-low 256))
result))
;; do not leave a copy of input string.
(fillarray block-high nil)
(fillarray block-low nil))))
(defun sha1-string-internal (string &optional binary)
(if binary
(sha1-binary string)
(encode-hex-string (sha1-binary string))))
(defun sha1-region-internal (beg end &optional binary)
(sha1-string-internal (buffer-substring-no-properties beg end) binary))
;;;
;;; application interface.
;;;
(defun sha1-region (beg end &optional binary)
(if (and sha1-use-external
sha1-maximum-internal-length
(> (abs (- end beg)) sha1-maximum-internal-length))
(sha1-region-external beg end binary)
(sha1-region-internal beg end binary)))
(defun sha1-string (string &optional binary)
(if (and sha1-use-external
sha1-maximum-internal-length
(> (length string) sha1-maximum-internal-length))
(sha1-string-external string binary)
(sha1-string-internal string binary)))
;;;###autoload
(defun sha1 (object &optional beg end binary)
"Return the SHA1 (Secure Hash Algorithm) of an object.
OBJECT is either a string or a buffer.
Optional arguments BEG and END denote buffer positions for computing the
hash of a portion of OBJECT.
If BINARY is non-nil, return a string in binary form."
(if (stringp object)
(sha1-string object binary)
(with-current-buffer object
(sha1-region (or beg (point-min)) (or end (point-max)) binary))))
(provide 'sha1)
;; arch-tag: c0f9abd0-ffc1-4557-aac6-ece7f2d4c901
;;; sha1.el ends here
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