-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-;;; primitive chunk operations
-
-(defun vlf-move-to-chunk (start end &optional minimal)
- "Move to chunk determined by START END.
-When given MINIMAL flag, skip non important operations.
-If same as current chunk is requested, do nothing."
- (unless (and (= start vlf-start-pos)
- (= end vlf-end-pos))
- (vlf-verify-size)
- (if (vlf-move-to-chunk-1 start end)
- (or minimal (vlf-update-buffer-name)))))
-
-(defun vlf-move-to-chunk-1 (start end)
- "Move to chunk determined by START END keeping as much edits if any.
-Return t if move hasn't been canceled."
- (let ((modified (buffer-modified-p))
- (start (max 0 start))
- (end (min end vlf-file-size))
- (edit-end (+ (position-bytes (point-max)) vlf-start-pos)))
- (cond
- ((and (= start vlf-start-pos) (= end edit-end))
- (unless modified
- (vlf-move-to-chunk-2 start end)
- t))
- ((or (<= edit-end start) (<= end vlf-start-pos))
- (when (or (not modified)
- (y-or-n-p "Chunk modified, are you sure? ")) ;full chunk renewal
- (set-buffer-modified-p nil)
- (vlf-move-to-chunk-2 start end)
- t))
- ((or (and (<= start vlf-start-pos) (<= edit-end end))
- (not modified)
- (y-or-n-p "Chunk modified, are you sure? "))
- (let ((pos (+ (position-bytes (point)) vlf-start-pos))
- (shift-start 0)
- (shift-end 0)
- (inhibit-read-only t))
- (cond ((< end edit-end)
- (let* ((del-pos (1+ (byte-to-position
- (- end vlf-start-pos))))
- (del-len (length (encode-coding-region
- del-pos (point-max)
- buffer-file-coding-system
- t))))
- (setq end (- (if (zerop vlf-end-pos)
- vlf-file-size
- vlf-end-pos)
- del-len))
- (vlf-with-undo-disabled
- (delete-region del-pos (point-max)))))
- ((< edit-end end)
- (let ((edit-end-pos (point-max)))
- (goto-char edit-end-pos)
- (vlf-with-undo-disabled
- (insert-file-contents buffer-file-name nil
- vlf-end-pos end)
- (setq shift-end (cdr (vlf-adjust-chunk
- vlf-end-pos end nil t
- edit-end-pos)))))))
- (cond ((< vlf-start-pos start)
- (let* ((del-pos (1+ (byte-to-position
- (- start vlf-start-pos))))
- (del-len (length (encode-coding-region
- (point-min) del-pos
- buffer-file-coding-system
- t))))
- (setq start (+ vlf-start-pos del-len))
- (vlf-with-undo-disabled
- (delete-region (point-min) del-pos))))
- ((< start vlf-start-pos)
- (let ((edit-end-pos (point-max)))
- (goto-char edit-end-pos)
- (vlf-with-undo-disabled
- (insert-file-contents buffer-file-name nil
- start vlf-start-pos)
- (setq shift-start (car
- (vlf-adjust-chunk start
- vlf-start-pos
- t nil
- edit-end-pos)))
- (goto-char (point-min))
- (insert (delete-and-extract-region edit-end-pos
- (point-max)))))))
- (setq start (- start shift-start))
- (goto-char (or (byte-to-position (- pos start))
- (byte-to-position (- pos vlf-start-pos))
- (point-max)))
- (setq vlf-start-pos start
- vlf-end-pos (+ end shift-end)))
- (set-buffer-modified-p modified)
- t))))
-
-(defun vlf-move-to-chunk-2 (start end)
- "Unconditionally move to chunk determined by START END."
- (setq vlf-start-pos (max 0 start)
- vlf-end-pos (min end vlf-file-size))
- (let ((inhibit-read-only t)
- (pos (position-bytes (point))))
- (vlf-with-undo-disabled
- (erase-buffer)
- (insert-file-contents buffer-file-name nil
- vlf-start-pos vlf-end-pos)
- (let ((shifts (vlf-adjust-chunk vlf-start-pos vlf-end-pos t
- t)))
- (setq vlf-start-pos (- vlf-start-pos (car shifts))
- vlf-end-pos (+ vlf-end-pos (cdr shifts)))
- (goto-char (or (byte-to-position (+ pos (car shifts)))
- (point-max))))))
- (set-buffer-modified-p nil)
- (set-visited-file-modtime))
-
-(defun vlf-adjust-chunk (start end &optional adjust-start adjust-end
- position)
- "Adjust chunk at absolute START to END till content can be\
-properly decoded. ADJUST-START determines if trying to prepend bytes\
- to the beginning, ADJUST-END - append to the end.
-Use buffer POSITION as start if given.
-Return number of bytes moved back for proper decoding and number of
-bytes added to the end."
- (let ((shift-start 0)
- (shift-end 0))
- (if adjust-start
- (let ((position (or position (point-min)))
- (chunk-size (- end start)))
- (while (and (not (zerop start))
- (< shift-start 4)
- (< 4 (abs (- chunk-size
- (length (encode-coding-region
- position (point-max)
- buffer-file-coding-system
- t))))))
- (setq shift-start (1+ shift-start)
- start (1- start)
- chunk-size (1+ chunk-size))
- (delete-region position (point-max))
- (goto-char position)
- (insert-file-contents buffer-file-name nil start end))))
- (if adjust-end
- (cond ((vlf-partial-decode-shown-p) ;remove raw bytes from end
- (goto-char (point-max))
- (while (eq (char-charset (preceding-char)) 'eight-bit)
- (setq shift-end (1- shift-end))
- (delete-char -1)))
- ((< end vlf-file-size) ;add bytes until new character is displayed
- (let ((position (or position (point-min)))
- (expected-size (buffer-size)))
- (while (and (progn
- (setq shift-end (1+ shift-end)
- end (1+ end))
- (delete-region position (point-max))
- (goto-char position)
- (insert-file-contents buffer-file-name
- nil start end)
- (< end vlf-file-size))
- (= expected-size (buffer-size))))))))
- (cons shift-start shift-end)))
-
-(defun vlf-partial-decode-shown-p ()
- "Determine if partial decode codes are displayed.
-This seems to be the case with GNU/Emacs before 24.4."
- (cond ((< emacs-major-version 24) t)
- ((< 24 emacs-major-version) nil)
- (t ;; TODO: use (< emacs-minor-version 4) after 24.4 release
- (string-lessp emacs-version "24.3.5"))))
-
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-;;; search
-
-(defun vlf-re-search (regexp count backward batch-step)
- "Search for REGEXP COUNT number of times forward or BACKWARD.
-BATCH-STEP is amount of overlap between successive chunks."
- (if (<= count 0)
- (error "Count must be positive"))
- (let* ((case-fold-search t)
- (match-chunk-start vlf-start-pos)
- (match-chunk-end vlf-end-pos)
- (match-start-pos (+ vlf-start-pos (position-bytes (point))))
- (match-end-pos match-start-pos)
- (to-find count)
- (reporter (make-progress-reporter
- (concat "Searching for " regexp "...")
- (if backward
- (- vlf-file-size vlf-end-pos)
- vlf-start-pos)
- vlf-file-size)))
- (vlf-with-undo-disabled
- (unwind-protect
- (catch 'end-of-file
- (if backward
- (while (not (zerop to-find))
- (cond ((re-search-backward regexp nil t)
- (setq to-find (1- to-find)
- match-chunk-start vlf-start-pos
- match-chunk-end vlf-end-pos
- match-start-pos (+ vlf-start-pos
- (position-bytes
- (match-beginning 0)))
- match-end-pos (+ vlf-start-pos
- (position-bytes
- (match-end 0)))))
- ((zerop vlf-start-pos)
- (throw 'end-of-file nil))
- (t (let ((batch-move (- vlf-start-pos
- (- vlf-batch-size
- batch-step))))
- (vlf-move-to-batch
- (if (< match-start-pos batch-move)
- (- match-start-pos vlf-batch-size)
- batch-move) t))
- (goto-char (if (< match-start-pos
- vlf-end-pos)
- (or (byte-to-position
- (- match-start-pos
- vlf-start-pos))
- (point-max))
- (point-max)))
- (progress-reporter-update
- reporter (- vlf-file-size
- vlf-start-pos)))))
- (while (not (zerop to-find))
- (cond ((re-search-forward regexp nil t)
- (setq to-find (1- to-find)
- match-chunk-start vlf-start-pos
- match-chunk-end vlf-end-pos
- match-start-pos (+ vlf-start-pos
- (position-bytes
- (match-beginning 0)))
- match-end-pos (+ vlf-start-pos
- (position-bytes
- (match-end 0)))))
- ((= vlf-end-pos vlf-file-size)
- (throw 'end-of-file nil))
- (t (let ((batch-move (- vlf-end-pos batch-step)))
- (vlf-move-to-batch
- (if (< batch-move match-end-pos)
- match-end-pos
- batch-move) t))
- (goto-char (if (< vlf-start-pos match-end-pos)
- (or (byte-to-position
- (- match-end-pos
- vlf-start-pos))
- (point-min))
- (point-min)))
- (progress-reporter-update reporter
- vlf-end-pos)))))
- (progress-reporter-done reporter))
- (set-buffer-modified-p nil)
- (if backward
- (vlf-goto-match match-chunk-start match-chunk-end
- match-end-pos match-start-pos
- count to-find)
- (vlf-goto-match match-chunk-start match-chunk-end
- match-start-pos match-end-pos
- count to-find))))))
-
-(defun vlf-goto-match (match-chunk-start match-chunk-end
- match-pos-start
- match-pos-end
- count to-find)
- "Move to MATCH-CHUNK-START MATCH-CHUNK-END surrounding \
-MATCH-POS-START and MATCH-POS-END.
-According to COUNT and left TO-FIND, show if search has been
-successful. Return nil if nothing found."
- (if (= count to-find)
- (progn (vlf-move-to-chunk match-chunk-start match-chunk-end)
- (goto-char (or (byte-to-position (- match-pos-start
- vlf-start-pos))
- (point-max)))
- (message "Not found")
- nil)
- (let ((success (zerop to-find)))
- (if success
- (vlf-update-buffer-name)
- (vlf-move-to-chunk match-chunk-start match-chunk-end))
- (let* ((match-end (or (byte-to-position (- match-pos-end
- vlf-start-pos))
- (point-max)))
- (overlay (make-overlay (byte-to-position
- (- match-pos-start
- vlf-start-pos))
- match-end)))
- (overlay-put overlay 'face 'match)
- (unless success
- (goto-char match-end)
- (message "Moved to the %d match which is last"
- (- count to-find)))
- (unwind-protect (sit-for 3)
- (delete-overlay overlay))
- t))))
-
-(defun vlf-re-search-forward (regexp count)
- "Search forward for REGEXP prefix COUNT number of times.
-Search is performed chunk by chunk in `vlf-batch-size' memory."
- (interactive (if (vlf-no-modifications)
- (list (read-regexp "Search whole file"
- (if regexp-history
- (car regexp-history)))
- (or current-prefix-arg 1))))
- (vlf-re-search regexp count nil (/ vlf-batch-size 8)))
-
-(defun vlf-re-search-backward (regexp count)
- "Search backward for REGEXP prefix COUNT number of times.
-Search is performed chunk by chunk in `vlf-batch-size' memory."
- (interactive (if (vlf-no-modifications)
- (list (read-regexp "Search whole file backward"
- (if regexp-history
- (car regexp-history)))
- (or current-prefix-arg 1))))
- (vlf-re-search regexp count t (/ vlf-batch-size 8)))
-
-(defun vlf-goto-line (n)
- "Go to line N. If N is negative, count from the end of file."
- (interactive (if (vlf-no-modifications)
- (list (read-number "Go to line: "))))
- (let ((start-pos vlf-start-pos)
- (end-pos vlf-end-pos)
- (pos (point))
- (success nil))
- (unwind-protect
- (if (< 0 n)
- (progn (vlf-beginning-of-file)
- (goto-char (point-min))
- (setq success (vlf-re-search "[\n\C-m]" (1- n)
- nil 0)))
- (vlf-end-of-file)
- (goto-char (point-max))
- (setq success (vlf-re-search "[\n\C-m]" (- n) t 0)))
- (if success
- (message "Onto line %s" n)
- (vlf-move-to-chunk start-pos end-pos)
- (goto-char pos)))))
-
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-;;; occur
-
-(defvar vlf-occur-mode-map
- (let ((map (make-sparse-keymap)))
- (define-key map "n" 'vlf-occur-next-match)
- (define-key map "p" 'vlf-occur-prev-match)
- (define-key map "\C-m" 'vlf-occur-visit)
- (define-key map "\M-\r" 'vlf-occur-visit-new-buffer)
- (define-key map [mouse-1] 'vlf-occur-visit)
- (define-key map "o" 'vlf-occur-show)
- map)
- "Keymap for command `vlf-occur-mode'.")
-
-(define-derived-mode vlf-occur-mode special-mode "VLF[occur]"
- "Major mode for showing occur matches of VLF opened files.")
-
-(defun vlf-occur-next-match ()
- "Move cursor to next match."
- (interactive)
- (if (eq (get-char-property (point) 'face) 'match)
- (goto-char (next-single-property-change (point) 'face)))
- (goto-char (or (text-property-any (point) (point-max) 'face 'match)
- (text-property-any (point-min) (point)
- 'face 'match))))
-
-(defun vlf-occur-prev-match ()
- "Move cursor to previous match."
- (interactive)
- (if (eq (get-char-property (point) 'face) 'match)
- (goto-char (previous-single-property-change (point) 'face)))
- (while (not (eq (get-char-property (point) 'face) 'match))
- (goto-char (or (previous-single-property-change (point) 'face)
- (point-max)))))
-
-(defun vlf-occur-show (&optional event)
- "Visit current `vlf-occur' link in a vlf buffer but stay in the \
-occur buffer. If original VLF buffer has been killed,
-open new VLF session each time.
-EVENT may hold details of the invocation."
- (interactive (list last-nonmenu-event))
- (let ((occur-buffer (if event
- (window-buffer (posn-window
- (event-end event)))
- (current-buffer))))
- (vlf-occur-visit event)
- (pop-to-buffer occur-buffer)))
-
-(defun vlf-occur-visit-new-buffer ()
- "Visit `vlf-occur' link in new vlf buffer."
- (interactive)
- (let ((current-prefix-arg t))
- (vlf-occur-visit)))
-
-(defun vlf-occur-visit (&optional event)
- "Visit current `vlf-occur' link in a vlf buffer.
-With prefix argument or if original VLF buffer has been killed,
-open new VLF session.
-EVENT may hold details of the invocation."
- (interactive (list last-nonmenu-event))
- (when event
- (set-buffer (window-buffer (posn-window (event-end event))))
- (goto-char (posn-point (event-end event))))
- (let* ((pos (point))
- (pos-relative (- pos (line-beginning-position) 1))
- (file (get-char-property pos 'file)))
- (if file
- (let ((chunk-start (get-char-property pos 'chunk-start))
- (chunk-end (get-char-property pos 'chunk-end))
- (vlf-buffer (get-char-property pos 'buffer))
- (occur-buffer (current-buffer))
- (match-pos (+ (get-char-property pos 'line-pos)
- pos-relative)))
- (cond (current-prefix-arg
- (setq vlf-buffer (vlf file))
- (switch-to-buffer occur-buffer))
- ((not (buffer-live-p vlf-buffer))
- (or (catch 'found
- (dolist (buf (buffer-list))
- (set-buffer buf)
- (and vlf-mode (equal file buffer-file-name)
- (setq vlf-buffer buf)
- (throw 'found t))))
- (setq vlf-buffer (vlf file)))
- (switch-to-buffer occur-buffer)))
- (pop-to-buffer vlf-buffer)
- (vlf-move-to-chunk chunk-start chunk-end)
- (goto-char match-pos)))))
-
-(defun vlf-occur (regexp)
- "Make whole file occur style index for REGEXP.
-Prematurely ending indexing will still show what's found so far."
- (interactive (list (read-regexp "List lines matching regexp"
- (if regexp-history
- (car regexp-history)))))
- (if (buffer-modified-p) ;use temporary buffer not to interfere with modifications
- (let ((vlf-buffer (current-buffer))
- (file buffer-file-name)
- (batch-size vlf-batch-size))
- (with-temp-buffer
- (setq buffer-file-name file)
- (set-buffer-modified-p nil)
- (set (make-local-variable 'vlf-batch-size) batch-size)
- (vlf-mode 1)
- (goto-char (point-min))
- (vlf-with-undo-disabled
- (vlf-build-occur regexp vlf-buffer))))
- (let ((start-pos vlf-start-pos)
- (end-pos vlf-end-pos)
- (pos (point)))
- (vlf-beginning-of-file)
- (goto-char (point-min))
- (vlf-with-undo-disabled
- (unwind-protect (vlf-build-occur regexp (current-buffer))
- (vlf-move-to-chunk start-pos end-pos)
- (goto-char pos))))))
-
-(defun vlf-build-occur (regexp vlf-buffer)
- "Build occur style index for REGEXP over VLF-BUFFER."
- (let ((case-fold-search t)
- (line 1)
- (last-match-line 0)
- (last-line-pos (point-min))
- (file buffer-file-name)
- (total-matches 0)
- (match-end-pos (+ vlf-start-pos (position-bytes (point))))
- (occur-buffer (generate-new-buffer
- (concat "*VLF-occur " (file-name-nondirectory
- buffer-file-name)
- "*")))
- (line-regexp (concat "\\(?5:[\n\C-m]\\)\\|\\(?10:"
- regexp "\\)"))
- (batch-step (/ vlf-batch-size 8))
- (end-of-file nil)
- (reporter (make-progress-reporter
- (concat "Building index for " regexp "...")
- vlf-start-pos vlf-file-size)))
- (unwind-protect
- (progn
- (while (not end-of-file)
- (if (re-search-forward line-regexp nil t)
- (progn
- (setq match-end-pos (+ vlf-start-pos
- (position-bytes
- (match-end 0))))
- (if (match-string 5)
- (setq line (1+ line) ; line detected
- last-line-pos (point))
- (let* ((chunk-start vlf-start-pos)
- (chunk-end vlf-end-pos)
- (line-pos (line-beginning-position))
- (line-text (buffer-substring
- line-pos (line-end-position))))
- (with-current-buffer occur-buffer
- (unless (= line last-match-line) ;new match line
- (insert "\n:") ; insert line number
- (let* ((overlay-pos (1- (point)))
- (overlay (make-overlay
- overlay-pos
- (1+ overlay-pos))))
- (overlay-put overlay 'before-string
- (propertize
- (number-to-string line)
- 'face 'shadow)))
- (insert (propertize line-text ; insert line
- 'file file
- 'buffer vlf-buffer
- 'chunk-start chunk-start
- 'chunk-end chunk-end
- 'mouse-face '(highlight)
- 'line-pos line-pos
- 'help-echo
- (format "Move to line %d"
- line))))
- (setq last-match-line line
- total-matches (1+ total-matches))
- (let ((line-start (1+
- (line-beginning-position)))
- (match-pos (match-beginning 10)))
- (add-text-properties ; mark match
- (+ line-start match-pos (- last-line-pos))
- (+ line-start (match-end 10)
- (- last-line-pos))
- (list 'face 'match
- 'help-echo
- (format "Move to match %d"
- total-matches))))))))
- (setq end-of-file (= vlf-end-pos vlf-file-size))
- (unless end-of-file
- (let ((batch-move (- vlf-end-pos batch-step)))
- (vlf-move-to-batch (if (< batch-move match-end-pos)
- match-end-pos
- batch-move) t))
- (goto-char (if (< vlf-start-pos match-end-pos)
- (or (byte-to-position (- match-end-pos
- vlf-start-pos))
- (point-min))
- (point-min)))
- (setq last-match-line 0
- last-line-pos (line-beginning-position))
- (progress-reporter-update reporter vlf-end-pos))))
- (progress-reporter-done reporter))
- (set-buffer-modified-p nil)
- (if (zerop total-matches)
- (progn (with-current-buffer occur-buffer
- (set-buffer-modified-p nil))
- (kill-buffer occur-buffer)
- (message "No matches for \"%s\"" regexp))
- (with-current-buffer occur-buffer
- (goto-char (point-min))
- (insert (propertize
- (format "%d matches in %d lines for \"%s\" \
-in file: %s" total-matches line regexp file)
- 'face 'underline))
- (set-buffer-modified-p nil)
- (forward-char 2)
- (vlf-occur-mode))
- (display-buffer occur-buffer)))))
-
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-;;; saving
-
-(defun vlf-write ()
- "Write current chunk to file. Always return true to disable save.
-If changing size of chunk, shift remaining file content."
- (interactive)
- (and (buffer-modified-p)
- (or (verify-visited-file-modtime (current-buffer))
- (y-or-n-p "File has changed since visited or saved. \
-Save anyway? "))
- (if (zerop vlf-file-size) ;new file
- (progn
- (write-region nil nil buffer-file-name vlf-start-pos t)
- (setq vlf-file-size (vlf-get-file-size
- buffer-file-truename)
- vlf-end-pos vlf-file-size)
- (vlf-update-buffer-name))
- (let* ((region-length (length (encode-coding-region
- (point-min) (point-max)
- buffer-file-coding-system t)))
- (size-change (- vlf-end-pos vlf-start-pos
- region-length)))
- (if (zerop size-change)
- (write-region nil nil buffer-file-name vlf-start-pos t)
- (let ((pos (point)))
- (if (< 0 size-change)
- (vlf-file-shift-back size-change)
- (vlf-file-shift-forward (- size-change))
- (vlf-verify-size))
- (vlf-move-to-chunk-2 vlf-start-pos
- (if (< (- vlf-end-pos vlf-start-pos)
- vlf-batch-size)
- (+ vlf-start-pos vlf-batch-size)
- vlf-end-pos))
- (vlf-update-buffer-name)
- (goto-char pos))))))
- t)
-
-(defun vlf-file-shift-back (size-change)
- "Shift file contents SIZE-CHANGE bytes back."
- (write-region nil nil buffer-file-name vlf-start-pos t)
- (let ((read-start-pos vlf-end-pos)
- (coding-system-for-write 'no-conversion)
- (reporter (make-progress-reporter "Adjusting file content..."
- vlf-end-pos
- vlf-file-size)))
- (vlf-with-undo-disabled
- (while (vlf-shift-batch read-start-pos (- read-start-pos
- size-change))
- (setq read-start-pos (+ read-start-pos vlf-batch-size))
- (progress-reporter-update reporter read-start-pos))
- ;; pad end with space
- (erase-buffer)
- (vlf-verify-size)
- (insert-char 32 size-change))
- (write-region nil nil buffer-file-name (- vlf-file-size
- size-change) t)
- (progress-reporter-done reporter)))
-
-(defun vlf-shift-batch (read-pos write-pos)
- "Read `vlf-batch-size' bytes from READ-POS and write them \
-back at WRITE-POS. Return nil if EOF is reached, t otherwise."
- (erase-buffer)
- (vlf-verify-size)
- (let ((read-end (+ read-pos vlf-batch-size)))
- (insert-file-contents-literally buffer-file-name nil
- read-pos
- (min vlf-file-size read-end))
- (write-region nil nil buffer-file-name write-pos 0)
- (< read-end vlf-file-size)))
-
-(defun vlf-file-shift-forward (size-change)
- "Shift file contents SIZE-CHANGE bytes forward.
-Done by saving content up front and then writing previous batch."
- (let ((read-size (max (/ vlf-batch-size 2) size-change))
- (read-pos vlf-end-pos)
- (write-pos vlf-start-pos)
- (reporter (make-progress-reporter "Adjusting file content..."
- vlf-start-pos
- vlf-file-size)))
- (vlf-with-undo-disabled
- (when (vlf-shift-batches read-size read-pos write-pos t)
- (setq write-pos (+ read-pos size-change)
- read-pos (+ read-pos read-size))
- (progress-reporter-update reporter write-pos)
- (let ((coding-system-for-write 'no-conversion))
- (while (vlf-shift-batches read-size read-pos write-pos nil)
- (setq write-pos (+ read-pos size-change)
- read-pos (+ read-pos read-size))
- (progress-reporter-update reporter write-pos)))))
- (progress-reporter-done reporter)))
-
-(defun vlf-shift-batches (read-size read-pos write-pos hide-read)
- "Append READ-SIZE bytes of file starting at READ-POS.
-Then write initial buffer content to file at WRITE-POS.
-If HIDE-READ is non nil, temporarily hide literal read content.
-Return nil if EOF is reached, t otherwise."
- (vlf-verify-size)
- (let ((read-more (< read-pos vlf-file-size))
- (start-write-pos (point-min))
- (end-write-pos (point-max)))
- (when read-more
- (goto-char end-write-pos)
- (insert-file-contents-literally buffer-file-name nil read-pos
- (min vlf-file-size
- (+ read-pos read-size))))
- ;; write
- (if hide-read ; hide literal region if user has to choose encoding
- (narrow-to-region start-write-pos end-write-pos))
- (write-region start-write-pos end-write-pos
- buffer-file-name write-pos 0)
- (delete-region start-write-pos end-write-pos)
- (if hide-read (widen))
- read-more))
-