ext/curses/view2.rb

   1 #!/usr/local/bin/ruby
   2
   3 require "curses"
   4
   5 if ARGV.size != 1 then
   6   printf("usage: view file\n");
   7   exit
   8 end
   9 begin
  10   fp = open(ARGV[0], "r")
  11 rescue
  12   raise "cannot open file: #{ARGV[1]}"
  13 end
  14
  15 # signal(SIGINT, finish)
  16
  17 Curses.init_screen
  18 Curses.nonl
  19 Curses.cbreak
  20 Curses.noecho
  21
  22 $screen = Curses.stdscr
  23
  24 $screen.scrollok(true)
  25 #$screen.keypad(true)
  26
  27 # slurp the file
  28 $data_lines = []
  29 fp.each_line { |l|
  30   $data_lines.push(l.chop)
  31 }
  32 fp.close
  33
  34 $top = 0
  35 $data_lines[0..$screen.maxy-1].each_with_index{|line, idx|
  36   $screen.setpos(idx, 0)
  37   $screen.addstr(line)
  38 }
  39 $screen.setpos(0,0)
  40 $screen.refresh
  41
  42 def scroll_up
  43   if( $top > 0 )
  44     $screen.scrl(-1)
  45     $top -= 1
  46     str = $data_lines[$top]
  47     if( str )
  48       $screen.setpos(0, 0)
  49       $screen.addstr(str)
  50     end
  51     return true
  52   else
  53     return false
  54   end
  55 end
  56
  57 def scroll_down
  58   if( $top + $screen.maxy < $data_lines.length )
  59     $screen.scrl(1)
  60     $top += 1
  61     str = $data_lines[$top + $screen.maxy - 1]
  62     if( str )
  63       $screen.setpos($screen.maxy - 1, 0)
  64       $screen.addstr(str)
  65     end
  66     return true
  67   else
  68     return false
  69   end
  70 end
  71
  72 while true
  73   result = true
  74   c = Curses.getch
  75   case c
  76   when Curses::KEY_DOWN, Curses::KEY_CTRL_N
  77     result = scroll_down
  78   when Curses::KEY_UP, Curses::KEY_CTRL_P
  79     result = scroll_up
  80   when Curses::KEY_NPAGE, ?\s  # white space
  81     for i in 0..($screen.maxy - 2)
  82       if( ! scroll_down )
  83         if( i == 0 )
  84           result = false
  85         end
  86         break
  87       end
  88     end
  89   when Curses::KEY_PPAGE
  90     for i in 0..($screen.maxy - 2)
  91       if( ! scroll_up )
  92         if( i == 0 )
  93           result = false
  94         end
  95         break
  96       end
  97     end
  98   when Curses::KEY_LEFT, Curses::KEY_CTRL_T
  99     while( scroll_up )
 100     end
 101   when Curses::KEY_RIGHT, Curses::KEY_CTRL_B
 102     while( scroll_down )
 103     end
 104   when ?q
 105     break
 106   else
 107     $screen.setpos(0,0)
 108     $screen.addstr("[unknown key `#{Curses.keyname(c)}'=#{c}] ")
 109   end
 110   if( !result )
 111     Curses.beep
 112   end
 113   $screen.setpos(0,0)
 114 end
 115 Curses.close_screen