mirror of
https://github.com/m00natic/vlfi.git
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286 lines
10 KiB
EmacsLisp
286 lines
10 KiB
EmacsLisp
;;; vlfi.el --- View Large Files Improved
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;;; -*- lexical-bind: t -*-
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;; Copyright (C) 2006, 2012, 2013 Free Software Foundation, Inc.
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;; Version: 0.3
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;; Keywords: large files, utilities
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;; Authors: 2006 Mathias Dahl <mathias.dahl@gmail.com>
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;; 2012 Sam Steingold <sds@gnu.org>
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;; 2013 Andrey Kotlarski <m00naticus@gmail.com>
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;; This file is free software; you can redistribute it and/or modify
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;; it under the terms of the GNU General Public License as published by
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;; the Free Software Foundation; either version 2, or (at your option)
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;; any later version.
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;; This file is distributed in the hope that it will be useful,
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;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;; GNU General Public License for more details.
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;; You should have received a copy of the GNU General Public License
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;; along with GNU Emacs; see the file COPYING. If not, write to
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;; the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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;; Boston, MA 02111-1307, USA.
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;;; Commentary:
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;; This package provides the M-x vlfi command, which visits part of a
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;; large file in a read-only buffer without visiting the entire file.
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;; The buffer uses VLFI mode, which defines the commands M-<next>
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;; (vlfi-next-batch) and M-<prior> (vlfi-prev-batch) to visit other
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;; parts of the file. The option `vlfi-batch-size' specifies the size
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;; of each batch, in bytes.
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;; This package is an improved fork of the vlf.el package.
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;;; Code:
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(defgroup vlfi nil
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"View Large Files in Emacs."
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:prefix "vlfi-"
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:group 'files)
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(defcustom vlfi-batch-size 1024
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"Defines how large each batch of file data is (in bytes)."
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:type 'integer
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:group 'vlfi)
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;; Keep track of file position.
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(defvar vlfi-start-pos)
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(defvar vlfi-end-pos)
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(defvar vlfi-file-size)
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(defvar vlfi-mode-map
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(let ((map (make-sparse-keymap)))
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(define-key map [M-next] 'vlfi-next-batch)
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(define-key map [M-prior] 'vlfi-prev-batch)
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(define-key map (kbd "M-+") 'vlfi-change-batch-size)
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(define-key map (kbd "M--")
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(lambda () "Decrease vlfi batch size by factor of 2."
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(interactive)
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(vlfi-change-batch-size t)))
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(define-key map "\C-c\C-s" 'vlfi-re-search-forward)
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(define-key map "\C-c\C-r" 'vlfi-re-search-backward)
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map)
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"Keymap for `vlfi-mode'.")
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(define-derived-mode vlfi-mode special-mode "VLFI"
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"Mode to browse large files in."
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(setq buffer-read-only t)
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(set-buffer-modified-p nil)
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(make-local-variable 'vlfi-batch-size)
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(make-local-variable 'vlfi-start-pos)
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(make-local-variable 'vlfi-file-size))
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(defun vlfi-change-batch-size (decrease)
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"Change the buffer-local value of `vlfi-batch-size'.
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Normally, the value is doubled;
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with the prefix argument DECREASE it is halved."
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(interactive "P")
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(or (assq 'vlfi-batch-size (buffer-local-variables))
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(error "%s is not local in this buffer" 'vlfi-batch-size))
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(setq vlfi-batch-size
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(if decrease
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(/ vlfi-batch-size 2)
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(* vlfi-batch-size 2)))
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(vlfi-update-buffer-name))
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(defun vlfi-format-buffer-name ()
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"Return format for vlfi buffer name."
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(let ((vlfi-file-size-float (float vlfi-file-size)))
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(format "%s(%s)[%.2f-%.2f%%%%](%d)"
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(file-name-nondirectory buffer-file-name)
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(file-size-human-readable vlfi-file-size)
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(* 100 (/ vlfi-start-pos vlfi-file-size-float))
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(* 100 (/ vlfi-end-pos vlfi-file-size-float))
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vlfi-batch-size)))
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(defun vlfi-update-buffer-name ()
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"Update the current buffer name."
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(rename-buffer (vlfi-format-buffer-name) t))
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(defun vlfi-next-batch (append)
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"Display the next batch of file data.
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When prefix argument is supplied and positive
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jump over APPEND number of batches.
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When prefix argument is negative
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append next APPEND number of batches to the existing buffer."
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(interactive "p")
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(let ((end (+ vlfi-end-pos (* vlfi-batch-size
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(abs append)))))
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(when (< vlfi-file-size end) ; re-check file size
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(setq vlfi-file-size (nth 7 (file-attributes buffer-file-name)))
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(cond ((= vlfi-end-pos vlfi-file-size)
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(error "Already at EOF"))
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((< vlfi-file-size end)
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(setq end vlfi-file-size))))
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(let ((inhibit-read-only t)
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(do-append (< append 0)))
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(if do-append
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(goto-char (point-max))
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(setq vlfi-start-pos (- end vlfi-batch-size))
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(erase-buffer))
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(insert-file-contents buffer-file-name nil
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(if do-append
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vlfi-end-pos
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vlfi-start-pos)
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end))
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(setq vlfi-end-pos end))
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(set-buffer-modified-p nil)
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(vlfi-update-buffer-name))
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(defun vlfi-prev-batch (prepend)
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"Display the previous batch of file data.
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When prefix argument is supplied and positive
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jump over PREPEND number of batches.
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When prefix argument is negative
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append previous PREPEND number of batches to the existing buffer."
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(interactive "p")
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(if (zerop vlfi-start-pos)
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(error "Already at BOF"))
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(let ((inhibit-read-only t)
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(start (max 0 (- vlfi-start-pos (* vlfi-batch-size
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(abs prepend)))))
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(do-prepend (< prepend 0)))
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(if do-prepend
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(goto-char (point-min))
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(setq vlfi-end-pos (+ start vlfi-batch-size))
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(erase-buffer))
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(insert-file-contents buffer-file-name nil start
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(if do-prepend
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vlfi-start-pos
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vlfi-end-pos))
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(setq vlfi-start-pos start))
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(set-buffer-modified-p nil)
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(vlfi-update-buffer-name))
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;;;###autoload
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(defun vlfi (from-end file)
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"View a Large File in Emacs.
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With FROM-END prefix, view from the back.
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FILE is the file to open.
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Batches of the file data from FILE will be displayed in a
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read-only buffer.
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You can customize the number of bytes to
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display by customizing `vlfi-batch-size'."
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(interactive "P\nfFile to open: ")
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(with-current-buffer (generate-new-buffer "*vlfi*")
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(buffer-disable-undo)
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(setq buffer-file-name file
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vlfi-file-size (nth 7 (file-attributes file)))
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(if from-end
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(setq vlfi-start-pos (max 0
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(- vlfi-file-size vlfi-batch-size))
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vlfi-end-pos vlfi-file-size)
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(setq vlfi-start-pos 0
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vlfi-end-pos (min vlfi-batch-size vlfi-file-size)))
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(vlfi-update-buffer-name)
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(insert-file-contents buffer-file-name nil
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vlfi-start-pos vlfi-end-pos)
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(vlfi-mode)
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(switch-to-buffer (current-buffer))))
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;;;###autoload
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(defun dired-vlfi (from-end)
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"In Dired, visit the file on this line in VLFI mode.
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With FROM-END prefix, view from the back."
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(interactive "P")
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(vlfi from-end (dired-get-file-for-visit)))
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;;;###autoload
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(eval-after-load "dired"
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'(define-key dired-mode-map "V" 'dired-vlfi))
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;;;###autoload
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(defun vlfi-if-file-too-large (size op-type &optional filename)
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"If file SIZE larger than `large-file-warning-threshold', \
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allow user to view file with `vlfi', open it normally or abort.
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OP-TYPE specifies the file operation being performed over FILENAME."
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(and large-file-warning-threshold size
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(> size large-file-warning-threshold)
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(let ((char nil))
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(while (not (memq (setq char
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(read-event
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(propertize
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(format "File %s is large (%s): \
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%s normally (o), %s with vlfi (v) or abort (a)"
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(file-name-nondirectory filename)
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(file-size-human-readable size)
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op-type op-type)
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'face 'minibuffer-prompt)))
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'(?o ?O ?v ?V ?a ?A))))
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(cond ((memq char '(?o ?O)))
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((memq char '(?v ?V))
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(vlfi nil filename)
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(error ""))
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((memq char '(?a ?A))
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(error "Aborted"))))))
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;;; hijack `abort-if-file-too-large'
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;;;###autoload
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(fset 'abort-if-file-too-large 'vlfi-if-file-too-large)
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;;; search
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(defun vlfi-re-search (regexp backward count)
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"Search for REGEXP BACKWARD or forward COUNT number of times."
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(let ((start vlfi-start-pos)
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(end vlfi-end-pos)
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(pos (point))
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(to-find count)
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(search-reporter (make-progress-reporter
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(concat "Searching for " regexp)
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(if backward
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(- vlfi-file-size vlfi-start-pos)
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vlfi-start-pos)
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vlfi-file-size)))
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(unwind-protect
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(catch 'end-of-file
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(if backward
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(while (not (zerop to-find))
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(cond ((re-search-backward regexp nil t)
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(setq to-find (1- to-find)))
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((zerop vlfi-start-pos)
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(throw 'end-of-file nil))
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(t (vlfi-prev-batch 1)
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(progress-reporter-update
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search-reporter (- vlfi-file-size
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vlfi-end-pos)))))
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(while (not (zerop to-find))
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(cond ((re-search-forward regexp nil t)
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(setq to-find (1- to-find)))
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((= vlfi-end-pos vlfi-file-size)
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(throw 'end-of-file nil))
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(t (vlfi-next-batch 1)
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(progress-reporter-update search-reporter
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vlfi-end-pos))))))
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(progress-reporter-done search-reporter)
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(or (zerop to-find)
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(if (< to-find count)
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(message "Moved to the %d match which is last"
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(- count to-find))
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(let ((inhibit-read-only t))
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(erase-buffer)
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(insert-file-contents buffer-file-name nil start end))
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(goto-char pos)
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(setq vlfi-start-pos start
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vlfi-end-pos end)
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(set-buffer-modified-p nil)
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(vlfi-update-buffer-name)
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(message "Not found"))))))
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(defun vlfi-re-search-forward (regexp count)
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"Search forward for REGEXP COUNT number of times."
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(interactive "sSearch whole file: \np")
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(vlfi-re-search regexp nil count))
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(defun vlfi-re-search-backward (regexp count)
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"Search backward for REGEXP COUNT number of times."
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(interactive "sSearch whole file backward: \np")
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(vlfi-re-search regexp t count))
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(provide 'vlfi)
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;;; vlfi.el ends here
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