From ddfb0a34ce527efab19ee4458f8d31fd1bde5dc5 Mon Sep 17 00:00:00 2001 From: Karl Heuer Date: Fri, 16 Feb 1996 00:36:52 +0000 Subject: [PATCH] Doc changes. (decipher-char): Added defvar (and also for following variables). (decipher--prev-char): Renamed from decipher-prev-char. (decipher--digram): Renamed from digram. (decipher--digram-list): Renamed from digram-list. (decipher--before): Renamed from before-array. (decipher--after): Renamed from after-array. (decipher--freqs): Renamed from freq-array. --- lisp/play/decipher.el | 91 +++++++++++++++++++++++++------------------ 1 file changed, 54 insertions(+), 37 deletions(-) diff --git a/lisp/play/decipher.el b/lisp/play/decipher.el index f911a5631ca..fc78e83a966 100644 --- a/lisp/play/decipher.el +++ b/lisp/play/decipher.el @@ -73,7 +73,11 @@ ;;; Things To Do: ;; -;; 1. More functions for analyzing ciphertext +;; Email me if you have any suggestions or would like to help. +;; But be aware that I work on Decipher only sporadically. +;; +;; 1. The consonant-line shortcut +;; 2. More functions for analyzing ciphertext ;;;=================================================================== ;;; Variables: @@ -174,6 +178,18 @@ list of such cons cells.") (defvar decipher-pending-undo-list nil) +;; The following variables are used by the analysis functions +;; and are defined here to avoid byte-compiler warnings. +;; Don't mess with them unless you know what you're doing. +(defvar decipher-char nil + "See the functions decipher-loop-with-breaks and decipher-loop-no-breaks.") +(defvar decipher--prev-char) +(defvar decipher--digram) +(defvar decipher--digram-list) +(defvar decipher--before) +(defvar decipher--after) +(defvar decipher--freqs) + ;;;=================================================================== ;;; Code: ;;;=================================================================== @@ -750,42 +766,43 @@ TOTAL is the total number of letters in the ciphertext." ;; Perform frequency analysis on ciphertext. ;; ;; This function is called repeatedly with decipher-char set to each - ;; character of ciphertext. It uses decipher-prev-char to remember + ;; character of ciphertext. It uses decipher--prev-char to remember ;; the previous ciphertext character. ;; ;; It builds several data structures, which must be initialized ;; before the first call to decipher--analyze. The arrays are ;; indexed with A = 0, B = 1, ..., Z = 25, SPC = 26 (if used). - ;; after-array: (initialize to zeros) + ;; decipher--after: (initialize to zeros) ;; A vector of 26 vectors of 27 integers. The first vector ;; represents the number of times A follows each character, the ;; second vector represents B, and so on. - ;; before-array: (initialize to zeros) - ;; The same as after-array, but representing the number of times - ;; the character precedes each other character. - ;; digram-list: (initialize to nil) + ;; decipher--before: (initialize to zeros) + ;; The same as decipher--after, but representing the number of + ;; times the character precedes each other character. + ;; decipher--digram-list: (initialize to nil) ;; An alist with an entry for each digram (2-character sequence) ;; encountered. Each element is a cons cell (DIGRAM . FREQ), ;; where DIGRAM is a 2 character string and FREQ is the number ;; of times it occurs. - ;; freq-array: (initialize to zeros) + ;; decipher--freqs: (initialize to zeros) ;; A vector of 26 integers, counting the number of occurrences ;; of the corresponding characters. - (setq digram (format "%c%c" decipher-prev-char decipher-char)) - (incf (cdr (or (assoc digram digram-list) - (car (push (cons digram 0) digram-list))))) - (and (>= decipher-prev-char ?A) - (incf (aref (aref before-array (- decipher-prev-char ?A)) + (setq decipher--digram (format "%c%c" decipher--prev-char decipher-char)) + (incf (cdr (or (assoc decipher--digram decipher--digram-list) + (car (push (cons decipher--digram 0) + decipher--digram-list))))) + (and (>= decipher--prev-char ?A) + (incf (aref (aref decipher--before (- decipher--prev-char ?A)) (if (equal decipher-char ?\ ) 26 (- decipher-char ?A))))) (and (>= decipher-char ?A) - (incf (aref freq-array (- decipher-char ?A))) - (incf (aref (aref after-array (- decipher-char ?A)) - (if (equal decipher-prev-char ?\ ) + (incf (aref decipher--freqs (- decipher-char ?A))) + (incf (aref (aref decipher--after (- decipher-char ?A)) + (if (equal decipher--prev-char ?\ ) 26 - (- decipher-prev-char ?A))))) - (setq decipher-prev-char decipher-char)) + (- decipher--prev-char ?A))))) + (setq decipher--prev-char decipher-char)) (defun decipher--digram-counts (counts) "Generate the counts for an adjacency list." @@ -815,29 +832,29 @@ TOTAL is the total number of letters in the ciphertext." (defun decipher-analyze-buffer () "Perform frequency analysis and store results in statistics buffer. Creates the statistics buffer if it doesn't exist." - (let ((decipher-prev-char (if decipher-ignore-spaces ?\ ?\*)) - (before-array (make-vector 26 nil)) - (after-array (make-vector 26 nil)) - (freq-array (make-vector 26 0)) + (let ((decipher--prev-char (if decipher-ignore-spaces ?\ ?\*)) + (decipher--before (make-vector 26 nil)) + (decipher--after (make-vector 26 nil)) + (decipher--freqs (make-vector 26 0)) (total-chars 0) - digram digram-list freq-list) + decipher--digram decipher--digram-list freq-list) (message "Scanning buffer...") (let ((i 26)) (while (>= (decf i) 0) - (aset before-array i (make-vector 27 0)) - (aset after-array i (make-vector 27 0)))) + (aset decipher--before i (make-vector 27 0)) + (aset decipher--after i (make-vector 27 0)))) (if decipher-ignore-spaces (progn (decipher-loop-no-breaks 'decipher--analyze) ;; The first character of ciphertext was marked as following a space: (let ((i 26)) (while (>= (decf i) 0) - (aset (aref after-array i) 26 0)))) + (aset (aref decipher--after i) 26 0)))) (decipher-loop-with-breaks 'decipher--analyze)) (message "Processing results...") - (setcdr (last digram-list 2) nil) ;Delete the phony "* " digram + (setcdr (last decipher--digram-list 2) nil) ;Delete the phony "* " digram ;; Sort the digram list by frequency and alphabetical order: - (setq digram-list (sort (sort digram-list + (setq decipher--digram-list (sort (sort decipher--digram-list (lambda (a b) (string< (car a) (car b)))) (lambda (a b) (> (cdr a) (cdr b))))) ;; Generate the frequency list: @@ -849,11 +866,11 @@ Creates the statistics buffer if it doesn't exist." (while (>= (decf i) 0) (setq freq-list (cons (list (+ i ?A) - (aref freq-array i) - (decipher--digram-total (aref before-array i) - (aref after-array i))) + (aref decipher--freqs i) + (decipher--digram-total (aref decipher--before i) + (aref decipher--after i))) freq-list) - total-chars (+ total-chars (aref freq-array i))))) + total-chars (+ total-chars (aref decipher--freqs i))))) (save-excursion ;; Switch to statistics buffer, creating it if necessary: (set-buffer (decipher-stats-buffer t)) @@ -874,11 +891,11 @@ Creates the statistics buffer if it doesn't exist." freq-list nil) "\n\n") ;; Display list of digrams in order of frequency: - (let* ((rows (floor (+ (length digram-list) 9) 10)) + (let* ((rows (floor (+ (length decipher--digram-list) 9) 10)) (i rows) temp-list) (while (> i 0) - (setq temp-list digram-list) + (setq temp-list decipher--digram-list) (while temp-list (insert (caar temp-list) (format "%3d " @@ -886,7 +903,7 @@ Creates the statistics buffer if it doesn't exist." (setq temp-list (nthcdr rows temp-list))) (delete-horizontal-space) (insert ?\n) - (setq digram-list (cdr digram-list) + (setq decipher--digram-list (cdr decipher--digram-list) i (1- i)))) ;; Display adjacency list for each letter, sorted in descending ;; order of the number of adjacent letters: @@ -899,13 +916,13 @@ Creates the statistics buffer if it doesn't exist." nil ;This letter was not used (setq i (- (car entry) ?A)) (insert ?\n " " - (decipher--digram-counts (aref before-array i)) ?\n + (decipher--digram-counts (aref decipher--before i)) ?\n (car entry) ": A B C D E F G H I J K L M N O P Q R S T U V W X Y Z *" (format "%4d %4d %3d%%\n " (third entry) (second entry) (/ (* 100 (second entry)) total-chars)) - (decipher--digram-counts (aref after-array i)) ?\n)))) + (decipher--digram-counts (aref decipher--after i)) ?\n)))) (setq buffer-read-only t) (set-buffer-modified-p nil) )) -- 2.39.2