Merge branch 'master' into chunk-opt2

Conflicts:
	vlfi.el

README.org

@@ -33,10 +33,11 @@ Emacs' Unicode support is leveraged so you'll not see bare bytes but
 characters decoded as if file is normally opened.  This holds for
 editing, search and indexing.
 
-** Bignums
+** 32-bit GNU/Emacs
 
-Regular Emacs integers are used, so if you have really huge file and
-Emacs doesn't have bignum support, VLFI will probably not quite work.
+Regular Emacs integers are used, so if you use 32-bit Emacs without
+bignum support and have really huge file (with size beyond the maximum
+integer value), VLFI will probably not quite work.
 
 ** Memory control
 
@@ -49,8 +50,9 @@ example you can directly press digits to enter prefix arguments.
 
 ** Changing major mode
 
-You can temporarily change major mode to whatever you like.  Saving
-will insert contents as intended.  You can return to *vlfi-mode* too.
+You can (temporarily) change major mode to whatever you like (for
+example hexl-mode).  Saving will insert contents as intended.  You can
+return to *vlfi-mode* too.
 
 * Detail usage
 
@@ -82,17 +84,20 @@ you'd better set somewhat bigger batch size beforehand.
 *l* jumps to given line in file.  This is done by searching from the
 beginning, so again the bigger current batch size, the quicker.
 
-** Edit
-
-*e* enters VLFI in edit mode.  If editing doesn't change size of
-the chunk, only this chunk is saved.  Otherwise the remaining part of
-the file is adjusted chunk by chunk, so again you'd better have bigger
-current batch size.  If chunk has been expanded the memory used is
-(batch size + difference to the original chunk size) x 2.
-
 ** Occur over whole file
 
 *o* builds index for given regular expression just like occur-mode.
 It does this chunk by chunk over the whole file.  Note that even if
 you prematurely stop it with *C-g*, it will still show index of what's
 found so far.
+
+** Edit
+
+*e* enters VLFI in edit mode.  If editing doesn't change size of
+the chunk, only this chunk is saved.  Otherwise the remaining part of
+the file is adjusted chunk by chunk, so again you'd better have bigger
+current batch size.  If chunk has been expanded the memory used is
+
+#+BEGIN_EXAMPLE
+(batch size + difference to the original chunk size) x 2
+#+END_EXAMPLE

vlfi.el

@@ -26,9 +26,9 @@
 ;;; Commentary:
 
 ;; This package provides the M-x vlfi command, which visits part of a
-;; large file in a read-only buffer without visiting the entire file.
+;; large file without loading the entire file.
 ;; The buffer uses VLFI mode, which defines several commands for
-;; moving around, searching and editing selected chunk of file.
+;; moving around, searching and editing selected part of file.
 
 ;; This package is upgraded version of the vlf.el package.
 
@@ -47,8 +47,7 @@
 ;;; Keep track of file position.
 (defvar vlfi-start-pos 0
   "Absolute position of the visible chunk start.")
-(defvar vlfi-end-pos 0
-  "Absolute position of the visible chunk end.")
+(defvar vlfi-end-pos 0 "Absolute position of the visible chunk end.")
 (defvar vlfi-file-size 0 "Total size of presented file.")
 
 (defvar vlfi-mode-map
@@ -426,8 +425,9 @@ Return cons \(success-status . number-of-bytes-moved-back\)."
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;; search
 
-(defun vlfi-re-search (regexp count backward)
-  "Search for REGEXP COUNT number of times forward or BACKWARD."
+(defun vlfi-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."
   (let* ((match-chunk-start vlfi-start-pos)
          (match-chunk-end vlfi-end-pos)
          (match-start-pos (+ vlfi-start-pos (position-bytes (point))))
@@ -438,8 +438,7 @@ Return cons \(success-status . number-of-bytes-moved-back\)."
                     (if backward
                         (- vlfi-file-size vlfi-end-pos)
                       vlfi-start-pos)
-                    vlfi-file-size))
-         (batch-step (/ vlfi-batch-size 8))) ; amount of chunk overlap
+                    vlfi-file-size)))
     (unwind-protect
         (catch 'end-of-file
           (if backward
@@ -550,7 +549,7 @@ Search is performed chunk by chunk in `vlfi-batch-size' memory."
                                   (if regexp-history
                                       (car regexp-history)))
                      (or current-prefix-arg 1)))
-  (vlfi-re-search regexp count nil))
+  (vlfi-re-search regexp count nil (/ vlfi-batch-size 8)))
 
 (defun vlfi-re-search-backward (regexp count)
   "Search backward for REGEXP prefix COUNT number of times.
@@ -559,7 +558,7 @@ Search is performed chunk by chunk in `vlfi-batch-size' memory."
                                   (if regexp-history
                                       (car regexp-history)))
                      (or current-prefix-arg 1)))
-  (vlfi-re-search regexp count t))
+  (vlfi-re-search regexp count t (/ vlfi-batch-size 8)))
 
 (defun vlfi-goto-line (n)
   "Go to line N."
@@ -571,8 +570,8 @@ Search is performed chunk by chunk in `vlfi-batch-size' memory."
     (unwind-protect
         (progn (vlfi-beginning-of-file)
                (goto-char (point-min))
-               (setq success (vlfi-re-search-forward "[\n\C-m]"
-                                                     (1- n))))
+               (setq success (vlfi-re-search "[\n\C-m]" (1- n)
+                                             nil 0)))
       (unless success
         (vlfi-move-to-chunk start-pos end-pos)
         (goto-char pos)))))