lisp/gnus/ietf-drums.el

   1 ;;; ietf-drums.el --- Functions for parsing RFC822bis headers
   2 ;; Copyright (C) 1998, 1999, 2000
   3 ;;        Free Software Foundation, Inc.
   4
   5 ;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
   6 ;; This file is part of GNU Emacs.
   7
   8 ;; GNU Emacs is free software; you can redistribute it and/or modify
   9 ;; it under the terms of the GNU General Public License as published by
  10 ;; the Free Software Foundation; either version 2, or (at your option)
  11 ;; any later version.
  12
  13 ;; GNU Emacs is distributed in the hope that it will be useful,
  14 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 ;; GNU General Public License for more details.
  17
  18 ;; You should have received a copy of the GNU General Public License
  19 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
  20 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  21 ;; Boston, MA 02111-1307, USA.
  22
  23 ;;; Commentary:
  24
  25 ;; DRUMS is an IETF Working Group that works (or worked) on the
  26 ;; successor to RFC822, "Standard For The Format Of Arpa Internet Text
  27 ;; Messages".  This library is based on
  28 ;; draft-ietf-drums-msg-fmt-05.txt, released on 1998-08-05.
  29
  30 ;;; Code:
  31
  32 (eval-when-compile (require 'cl))
  33 (require 'time-date)
  34 (require 'mm-util)
  35
  36 (defvar ietf-drums-no-ws-ctl-token "\001-\010\013\014\016-\037\177"
  37   "US-ASCII control characters excluding CR, LF and white space.")
  38 (defvar ietf-drums-text-token "\001-\011\013\014\016-\177"
  39   "US-ASCII characters exlcuding CR and LF.")
  40 (defvar ietf-drums-specials-token "()<>[]:;@\\,.\""
  41   "Special characters.")
  42 (defvar ietf-drums-quote-token "\\"
  43   "Quote character.")
  44 (defvar ietf-drums-wsp-token " \t"
  45   "White space.")
  46 (defvar ietf-drums-fws-regexp
  47   (concat "[" ietf-drums-wsp-token "]*\n[" ietf-drums-wsp-token "]+")
  48   "Folding white space.")
  49 (defvar ietf-drums-atext-token "-^a-zA-Z0-9!#$%&'*+/=?_`{|}~"
  50   "Textual token.")
  51 (defvar ietf-drums-dot-atext-token "-^a-zA-Z0-9!#$%&'*+/=?_`{|}~."
  52   "Textual token including full stop.")
  53 (defvar ietf-drums-qtext-token
  54   (concat ietf-drums-no-ws-ctl-token "\041\043-\133\135-\177")
  55   "Non-white-space control characaters, plus the rest of ASCII excluding backslash and doublequote.")
  56 (defvar ietf-drums-tspecials "][()<>@,;:\\\"/?="
  57   "Tspecials.")
  58
  59 (defvar ietf-drums-syntax-table
  60   (let ((table (copy-syntax-table emacs-lisp-mode-syntax-table)))
  61     (modify-syntax-entry ?\\ "/" table)
  62     (modify-syntax-entry ?< "(" table)
  63     (modify-syntax-entry ?> ")" table)
  64     (modify-syntax-entry ?@ "w" table)
  65     (modify-syntax-entry ?/ "w" table)
  66     (modify-syntax-entry ?= " " table)
  67     (modify-syntax-entry ?* " " table)
  68     (modify-syntax-entry ?\; " " table)
  69     (modify-syntax-entry ?\' " " table)
  70     table))
  71
  72 (defun ietf-drums-token-to-list (token)
  73   "Translate TOKEN into a list of characters."
  74   (let ((i 0)
  75         b e c out range)
  76     (while (< i (length token))
  77       (setq c (mm-char-int (aref token i)))
  78       (incf i)
  79       (cond
  80        ((eq c (mm-char-int ?-))
  81         (if b
  82             (setq range t)
  83           (push c out)))
  84        (range
  85         (while (<= b c)
  86           (push (mm-make-char 'ascii b) out)
  87           (incf b))
  88         (setq range nil))
  89        ((= i (length token))
  90         (push (mm-make-char 'ascii c) out))
  91        (t
  92         (when b
  93           (push (mm-make-char 'ascii b) out))
  94         (setq b c))))
  95     (nreverse out)))
  96
  97 (defsubst ietf-drums-init (string)
  98   (set-syntax-table ietf-drums-syntax-table)
  99   (insert string)
 100   (ietf-drums-unfold-fws)
 101   (goto-char (point-min)))
 102
 103 (defun ietf-drums-remove-comments (string)
 104   "Remove comments from STRING."
 105   (with-temp-buffer
 106     (let (c)
 107       (ietf-drums-init string)
 108       (while (not (eobp))
 109         (setq c (char-after))
 110         (cond
 111          ((eq c ?\")
 112           (forward-sexp 1))
 113          ((eq c ?\()
 114           (delete-region (point) (progn (forward-sexp 1) (point))))
 115          (t
 116           (forward-char 1))))
 117       (buffer-string))))
 118
 119 (defun ietf-drums-remove-whitespace (string)
 120   "Remove whitespace from STRING."
 121   (with-temp-buffer
 122     (ietf-drums-init string)
 123     (let (c)
 124       (while (not (eobp))
 125         (setq c (char-after))
 126         (cond
 127          ((eq c ?\")
 128           (forward-sexp 1))
 129          ((eq c ?\()
 130           (forward-sexp 1))
 131          ((memq c '(? ?\t ?\n))
 132           (delete-char 1))
 133          (t
 134           (forward-char 1))))
 135       (buffer-string))))
 136
 137 (defun ietf-drums-get-comment (string)
 138   "Return the first comment in STRING."
 139   (with-temp-buffer
 140     (ietf-drums-init string)
 141     (let (result c)
 142       (while (not (eobp))
 143         (setq c (char-after))
 144         (cond
 145          ((eq c ?\")
 146           (forward-sexp 1))
 147          ((eq c ?\()
 148           (setq result
 149                 (buffer-substring
 150                  (1+ (point))
 151                  (progn (forward-sexp 1) (1- (point))))))
 152          (t
 153           (forward-char 1))))
 154       result)))
 155
 156 (defun ietf-drums-strip (string)
 157   "Remove comments and whitespace from STRING."
 158   (ietf-drums-remove-whitespace (ietf-drums-remove-comments string)))
 159
 160 (defun ietf-drums-parse-address (string)
 161   "Parse STRING and return a MAILBOX / DISPLAY-NAME pair."
 162   (with-temp-buffer
 163     (let (display-name mailbox c display-string)
 164       (ietf-drums-init string)
 165       (while (not (eobp))
 166         (setq c (char-after))
 167         (cond
 168          ((or (eq c ? )
 169               (eq c ?\t))
 170           (forward-char 1))
 171          ((eq c ?\()
 172           (forward-sexp 1))
 173          ((eq c ?\")
 174           (push (buffer-substring
 175                  (1+ (point)) (progn (forward-sexp 1) (1- (point))))
 176                 display-name))
 177          ((looking-at (concat "[" ietf-drums-atext-token "@" "]"))
 178           (push (buffer-substring (point) (progn (forward-sexp 1) (point)))
 179                 display-name))
 180          ((eq c ?<)
 181           (setq mailbox
 182                 (ietf-drums-remove-whitespace
 183                  (ietf-drums-remove-comments
 184                   (buffer-substring
 185                    (1+ (point))
 186                    (progn (forward-sexp 1) (1- (point))))))))
 187          (t (error "Unknown symbol: %c" c))))
 188       ;; If we found no display-name, then we look for comments.
 189       (if display-name
 190           (setq display-string
 191                 (mapconcat 'identity (reverse display-name) " "))
 192         (setq display-string (ietf-drums-get-comment string)))
 193       (if (not mailbox)
 194           (when (string-match "@" display-string)
 195             (cons
 196              (mapconcat 'identity (nreverse display-name) "")
 197              (ietf-drums-get-comment string)))
 198         (cons mailbox display-string)))))
 199
 200 (defun ietf-drums-parse-addresses (string)
 201   "Parse STRING and return a list of MAILBOX / DISPLAY-NAME pairs."
 202   (with-temp-buffer
 203     (ietf-drums-init string)
 204     (let ((beg (point))
 205           pairs c)
 206       (while (not (eobp))
 207         (setq c (char-after))
 208         (cond
 209          ((memq c '(?\" ?< ?\())
 210           (forward-sexp 1))
 211          ((eq c ?,)
 212           (push (ietf-drums-parse-address (buffer-substring beg (point)))
 213                 pairs)
 214           (forward-char 1)
 215           (setq beg (point)))
 216          (t
 217           (forward-char 1))))
 218       (push (ietf-drums-parse-address (buffer-substring beg (point)))
 219             pairs)
 220       (nreverse pairs))))
 221
 222 (defun ietf-drums-unfold-fws ()
 223   "Unfold folding white space in the current buffer."
 224   (goto-char (point-min))
 225   (while (re-search-forward ietf-drums-fws-regexp nil t)
 226     (replace-match " " t t))
 227   (goto-char (point-min)))
 228
 229 (defun ietf-drums-parse-date (string)
 230   "Return an Emacs time spec from STRING."
 231   (apply 'encode-time (parse-time-string string)))
 232
 233 (defun ietf-drums-narrow-to-header ()
 234   "Narrow to the header section in the current buffer."
 235   (narrow-to-region
 236    (goto-char (point-min))
 237    (if (re-search-forward "^\r?$" nil 1)
 238        (match-beginning 0)
 239      (point-max)))
 240   (goto-char (point-min)))
 241
 242 (defun ietf-drums-quote-string (string)
 243   "Quote string if it needs quoting to be displayed in a header."
 244   (if (string-match (concat "[^" ietf-drums-atext-token "]") string)
 245       (concat "\"" string "\"")
 246     string))
 247
 248 (provide 'ietf-drums)
 249
 250 ;;; ietf-drums.el ends here