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Diffstat (limited to 'lisp/gnus/gnus-range.el')
| -rw-r--r-- | lisp/gnus/gnus-range.el | 281 |
1 files changed, 281 insertions, 0 deletions
diff --git a/lisp/gnus/gnus-range.el b/lisp/gnus/gnus-range.el new file mode 100644 index 00000000000..2ce1106e499 --- /dev/null +++ b/lisp/gnus/gnus-range.el @@ -0,0 +1,281 @@ +;;; gnus-range.el --- range and sequence functions for Gnus +;; Copyright (C) 1996,97 Free Software Foundation, Inc. + +;; Author: Lars Magne Ingebrigtsen <larsi@ifi.uio.no> +;; Keywords: news + +;; 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 2, 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., 59 Temple Place - Suite 330, +;; Boston, MA 02111-1307, USA. + +;;; Commentary: + +;;; Code: + +;;; List and range functions + +(defun gnus-last-element (list) + "Return last element of LIST." + (while (cdr list) + (setq list (cdr list))) + (car list)) + +(defun gnus-copy-sequence (list) + "Do a complete, total copy of a list." + (let (out) + (while (consp list) + (if (consp (car list)) + (push (gnus-copy-sequence (pop list)) out) + (push (pop list) out))) + (if list + (nconc (nreverse out) list) + (nreverse out)))) + +(defun gnus-set-difference (list1 list2) + "Return a list of elements of LIST1 that do not appear in LIST2." + (let ((list1 (copy-sequence list1))) + (while list2 + (setq list1 (delq (car list2) list1)) + (setq list2 (cdr list2))) + list1)) + +(defun gnus-sorted-complement (list1 list2) + "Return a list of elements of LIST1 that do not appear in LIST2. +Both lists have to be sorted over <." + (let (out) + (if (or (null list1) (null list2)) + (or list1 list2) + (while (and list1 list2) + (cond ((= (car list1) (car list2)) + (setq list1 (cdr list1) + list2 (cdr list2))) + ((< (car list1) (car list2)) + (setq out (cons (car list1) out)) + (setq list1 (cdr list1))) + (t + (setq out (cons (car list2) out)) + (setq list2 (cdr list2))))) + (nconc (nreverse out) (or list1 list2))))) + +(defun gnus-intersection (list1 list2) + (let ((result nil)) + (while list2 + (when (memq (car list2) list1) + (setq result (cons (car list2) result))) + (setq list2 (cdr list2))) + result)) + +(defun gnus-sorted-intersection (list1 list2) + ;; LIST1 and LIST2 have to be sorted over <. + (let (out) + (while (and list1 list2) + (cond ((= (car list1) (car list2)) + (setq out (cons (car list1) out) + list1 (cdr list1) + list2 (cdr list2))) + ((< (car list1) (car list2)) + (setq list1 (cdr list1))) + (t + (setq list2 (cdr list2))))) + (nreverse out))) + +(defun gnus-set-sorted-intersection (list1 list2) + ;; LIST1 and LIST2 have to be sorted over <. + ;; This function modifies LIST1. + (let* ((top (cons nil list1)) + (prev top)) + (while (and list1 list2) + (cond ((= (car list1) (car list2)) + (setq prev list1 + list1 (cdr list1) + list2 (cdr list2))) + ((< (car list1) (car list2)) + (setcdr prev (cdr list1)) + (setq list1 (cdr list1))) + (t + (setq list2 (cdr list2))))) + (setcdr prev nil) + (cdr top))) + +(defun gnus-compress-sequence (numbers &optional always-list) + "Convert list of numbers to a list of ranges or a single range. +If ALWAYS-LIST is non-nil, this function will always release a list of +ranges." + (let* ((first (car numbers)) + (last (car numbers)) + result) + (if (null numbers) + nil + (if (not (listp (cdr numbers))) + numbers + (while numbers + (cond ((= last (car numbers)) nil) ;Omit duplicated number + ((= (1+ last) (car numbers)) ;Still in sequence + (setq last (car numbers))) + (t ;End of one sequence + (setq result + (cons (if (= first last) first + (cons first last)) + result)) + (setq first (car numbers)) + (setq last (car numbers)))) + (setq numbers (cdr numbers))) + (if (and (not always-list) (null result)) + (if (= first last) (list first) (cons first last)) + (nreverse (cons (if (= first last) first (cons first last)) + result))))))) + +(defalias 'gnus-uncompress-sequence 'gnus-uncompress-range) +(defun gnus-uncompress-range (ranges) + "Expand a list of ranges into a list of numbers. +RANGES is either a single range on the form `(num . num)' or a list of +these ranges." + (let (first last result) + (cond + ((null ranges) + nil) + ((not (listp (cdr ranges))) + (setq first (car ranges)) + (setq last (cdr ranges)) + (while (<= first last) + (setq result (cons first result)) + (setq first (1+ first))) + (nreverse result)) + (t + (while ranges + (if (atom (car ranges)) + (when (numberp (car ranges)) + (setq result (cons (car ranges) result))) + (setq first (caar ranges)) + (setq last (cdar ranges)) + (while (<= first last) + (setq result (cons first result)) + (setq first (1+ first)))) + (setq ranges (cdr ranges))) + (nreverse result))))) + +(defun gnus-add-to-range (ranges list) + "Return a list of ranges that has all articles from both RANGES and LIST. +Note: LIST has to be sorted over `<'." + (if (not ranges) + (gnus-compress-sequence list t) + (setq list (copy-sequence list)) + (unless (listp (cdr ranges)) + (setq ranges (list ranges))) + (let ((out ranges) + ilist lowest highest temp) + (while (and ranges list) + (setq ilist list) + (setq lowest (or (and (atom (car ranges)) (car ranges)) + (caar ranges))) + (while (and list (cdr list) (< (cadr list) lowest)) + (setq list (cdr list))) + (when (< (car ilist) lowest) + (setq temp list) + (setq list (cdr list)) + (setcdr temp nil) + (setq out (nconc (gnus-compress-sequence ilist t) out))) + (setq highest (or (and (atom (car ranges)) (car ranges)) + (cdar ranges))) + (while (and list (<= (car list) highest)) + (setq list (cdr list))) + (setq ranges (cdr ranges))) + (when list + (setq out (nconc (gnus-compress-sequence list t) out))) + (setq out (sort out (lambda (r1 r2) + (< (or (and (atom r1) r1) (car r1)) + (or (and (atom r2) r2) (car r2)))))) + (setq ranges out) + (while ranges + (if (atom (car ranges)) + (when (cdr ranges) + (if (atom (cadr ranges)) + (when (= (1+ (car ranges)) (cadr ranges)) + (setcar ranges (cons (car ranges) + (cadr ranges))) + (setcdr ranges (cddr ranges))) + (when (= (1+ (car ranges)) (caadr ranges)) + (setcar (cadr ranges) (car ranges)) + (setcar ranges (cadr ranges)) + (setcdr ranges (cddr ranges))))) + (when (cdr ranges) + (if (atom (cadr ranges)) + (when (= (1+ (cdar ranges)) (cadr ranges)) + (setcdr (car ranges) (cadr ranges)) + (setcdr ranges (cddr ranges))) + (when (= (1+ (cdar ranges)) (caadr ranges)) + (setcdr (car ranges) (cdadr ranges)) + (setcdr ranges (cddr ranges)))))) + (setq ranges (cdr ranges))) + out))) + +(defun gnus-remove-from-range (ranges list) + "Return a list of ranges that has all articles from LIST removed from RANGES. +Note: LIST has to be sorted over `<'." + ;; !!! This function shouldn't look like this, but I've got a headache. + (gnus-compress-sequence + (gnus-sorted-complement + (gnus-uncompress-range ranges) list))) + +(defun gnus-member-of-range (number ranges) + (if (not (listp (cdr ranges))) + (and (>= number (car ranges)) + (<= number (cdr ranges))) + (let ((not-stop t)) + (while (and ranges + (if (numberp (car ranges)) + (>= number (car ranges)) + (>= number (caar ranges))) + not-stop) + (when (if (numberp (car ranges)) + (= number (car ranges)) + (and (>= number (caar ranges)) + (<= number (cdar ranges)))) + (setq not-stop nil)) + (setq ranges (cdr ranges))) + (not not-stop)))) + +(defun gnus-range-length (range) + "Return the length RANGE would have if uncompressed." + (length (gnus-uncompress-range range))) + +(defun gnus-sublist-p (list sublist) + "Test whether all elements in SUBLIST are members of LIST." + (let ((sublistp t)) + (while sublist + (unless (memq (pop sublist) list) + (setq sublistp nil + sublist nil))) + sublistp)) + +(defun gnus-range-add (range1 range2) + "Add RANGE2 to RANGE1 destructively." + (cond + ;; If either are nil, then the job is quite easy. + ((or (null range1) (null range2)) + (or range1 range2)) + (t + ;; I don't like thinking. + (gnus-compress-sequence + (sort + (nconc + (gnus-uncompress-range range1) + (gnus-uncompress-range range2)) + '<))))) + +(provide 'gnus-range) + +;;; gnus-range.el ends here |