Add --file-size option.

NEWS.VER

@@ -23,6 +23,8 @@
 * If XDG_DATA_HOME is set, find and store history file 
  in $XDG_DATA_HOME/lesshst rather than $HOME/.lesshst.
 
+* Add the --file-size option.
+
 * Fix bug which could leave terminal in mouse-reporting mode 
  after exiting less.
 

edit.c

@@ -19,6 +19,7 @@ extern int force_open;
 extern int is_tty;
 extern int sigs;
 extern int hshift;
+extern int want_filesize;
 extern IFILE curr_ifile;
 extern IFILE old_ifile;
 extern struct scrpos initial_scrpos;
@@ -480,7 +481,8 @@ edit_ifile(ifile)
  cmd_addhist(ml_examine, qfilename, 1);
  free(qfilename);
  }
-
+ if (want_filesize)
+ scan_eof();
  }
  free(filename);
  return (0);

less.hlp

@@ -205,6 +205,8 @@
  Don't display tildes after end of file.
  -# [_N] .... --shift=[_N]
  Set horizontal scroll amount (0 = one half screen width).
+ --file-size
+ Automatically determine the size of the input file.
  --follow-name
  The F command changes files if the input file is renamed.
  --incsearch

less.nro.VER

@@ -1079,6 +1079,12 @@ If the number is specified as a fraction, the actual number of
 scroll positions is recalculated if the terminal window is resized,
 so that the actual scroll remains at the specified fraction
 of the screen width.
+.IP "\-\-file-size"
+If \-\-file-size is specified,
+.I less
+will determine the size of the file 
+immediately after opening the file.
+Normally this is not done, because it can be slow if the input file is large.
 .IP "\-\-follow-name"
 Normally, if the input file is renamed while an F command is executing,
 .I less

linenum.c

@@ -462,3 +462,26 @@ currline(where)
  linenum--;
  return (linenum);
 }
+
+/*
+ * Scan entire file, counting line numbers.
+ */
+ public void
+scan_eof(VOID_PARAM)
+{
+ POSITION pos = 0;
+ LINENUM linenum = 0;
+
+ if (ch_seek(0))
+ return;
+ ierror("Determining length of file", NULL_PARG);
+ while (pos != NULL_POSITION)
+ {
+ /* For efficiency, only add one every 256 line numbers. */
+ if ((linenum++ % 256) == 0)
+ add_lnum(linenum, pos);
+ pos = forw_raw_line(pos, (char **)NULL, (int *)NULL);
+ if (ABORT_SIGS())
+ break;
+ }
+}

optfunc.c

@@ -51,6 +51,7 @@ extern int less_is_more;
 extern int linenum_width;
 extern int status_col_width;
 extern int use_color;
+extern int want_filesize;
 #if LOGFILE
 extern char *namelogfile;
 extern int force_logfile;
@@ -955,6 +956,27 @@ opt_status_col_width(type, s)
  }
 }
 
+/*
+ * Handler for the --file-size option.
+ */
+ /*ARGSUSED*/
+ public void
+opt_filesize(type, s)
+ int type;
+ char *s;
+{
+ switch (type)
+ {
+ case INIT:
+ case TOGGLE:
+ if (want_filesize && curr_ifile != NULL && ch_length() == NULL_POSITION)
+ scan_eof();
+ break;
+ case QUERY:
+ break;
+ }
+}
+
 #if LESSTEST
 /*
  * Handler for the --tty option.

opttbl.c

@@ -56,6 +56,7 @@ public int linenum_width; /* Width of line numbers */
 public int status_col_width; /* Width of status column */
 public int incr_search; /* Incremental search */
 public int use_color; /* Use UI color */
+public int want_filesize; /* */
 #if HILITE_SEARCH
 public int hilite_search; /* Highlight matched search patterns? */
 #endif
@@ -130,6 +131,7 @@ static struct optname linenum_width_optname = { "line-num-width", NULL };
 static struct optname status_col_width_optname = { "status-col-width", NULL };
 static struct optname incr_search_optname = { "incsearch", NULL };
 static struct optname use_color_optname = { "use-color", NULL };
+static struct optname want_filesize_optname = { "file-size", NULL };
 #if LESSTEST
 static struct optname ttyin_name_optname = { "tty", NULL };
 static struct optname rstat_optname = { "rstat", NULL };
@@ -545,6 +547,14 @@ static struct loption option[] =
  NULL
  }
  },
+ { OLETTER_NONE, &want_filesize_optname,
+ BOOL|REPAINT, OPT_OFF, &want_filesize, opt_filesize,
+ {
+ "Don't get size of each file",
+ "Get size of each file",
+ NULL
+ }
+ },
 #if LESSTEST
  { OLETTER_NONE, &ttyin_name_optname,
  STRING|NO_TOGGLE, 0, NULL, opt_ttyin_name,