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-rw-r--r--sample/curses/view2.rb149
1 files changed, 149 insertions, 0 deletions
diff --git a/sample/curses/view2.rb b/sample/curses/view2.rb
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+#!/usr/local/bin/ruby
+
+require "curses"
+
+
+# A curses based file viewer
+class FileViewer
+
+ # Create a new fileviewer, and view the file.
+ def initialize(filename)
+ @data_lines = []
+ @screen = nil
+ @top = nil
+ init_curses
+ load_file(filename)
+ interact
+ end
+
+ # Perform the curses setup
+ def init_curses
+ # signal(SIGINT, finish)
+
+ Curses.init_screen
+ Curses.nonl
+ Curses.cbreak
+ Curses.noecho
+
+ @screen = Curses.stdscr
+
+ @screen.scrollok(true)
+ #$screen.keypad(true)
+ end
+
+ # Load the file into memory, and put
+ # the first part on the curses display.
+ def load_file(filename)
+ fp = open(filename, "r") do |fp|
+ # slurp the file
+ fp.each_line { |l|
+ @data_lines.push(l.chop)
+ }
+ end
+ @top = 0
+ @data_lines[0..@screen.maxy-1].each_with_index{|line, idx|
+ @screen.setpos(idx, 0)
+ @screen.addstr(line)
+ }
+ @screen.setpos(0,0)
+ @screen.refresh
+ rescue
+ raise "cannot open file '#{filename}' for reading"
+ end
+
+
+ # Scroll the display up by one line
+ def scroll_up
+ if( @top > 0 )
+ @screen.scrl(-1)
+ @top -= 1
+ str = @data_lines[@top]
+ if( str )
+ @screen.setpos(0, 0)
+ @screen.addstr(str)
+ end
+ return true
+ else
+ return false
+ end
+ end
+
+ # Scroll the display down by one line
+ def scroll_down
+ if( @top + @screen.maxy < @data_lines.length )
+ @screen.scrl(1)
+ @top += 1
+ str = @data_lines[@top + @screen.maxy - 1]
+ if( str )
+ @screen.setpos(@screen.maxy - 1, 0)
+ @screen.addstr(str)
+ end
+ return true
+ else
+ return false
+ end
+ end
+
+ # Allow the user to interact with the display.
+ # This uses EMACS-like keybindings, and also
+ # vi-like keybindings as well, except that left
+ # and right move to the beginning and end of the
+ # file, respectively.
+ def interact
+ while true
+ result = true
+ c = Curses.getch
+ case c
+ when Curses::KEY_DOWN, Curses::KEY_CTRL_N, ?j
+ result = scroll_down
+ when Curses::KEY_UP, Curses::KEY_CTRL_P, ?k
+ result = scroll_up
+ when Curses::KEY_NPAGE, ?\s # white space
+ for i in 0..(@screen.maxy - 2)
+ if( ! scroll_down )
+ if( i == 0 )
+ result = false
+ end
+ break
+ end
+ end
+ when Curses::KEY_PPAGE
+ for i in 0..(@screen.maxy - 2)
+ if( ! scroll_up )
+ if( i == 0 )
+ result = false
+ end
+ break
+ end
+ end
+ when Curses::KEY_LEFT, Curses::KEY_CTRL_T, ?h
+ while( scroll_up )
+ end
+ when Curses::KEY_RIGHT, Curses::KEY_CTRL_B, ?l
+ while( scroll_down )
+ end
+ when ?q
+ break
+ else
+ @screen.setpos(0,0)
+ @screen.addstr("[unknown key `#{Curses.keyname(c)}'=#{c}] ")
+ end
+ if( !result )
+ Curses.beep
+ end
+ @screen.setpos(0,0)
+ end
+ Curses.close_screen
+ end
+end
+
+
+# If we are being run as a main program...
+if __FILE__ == $0
+ if ARGV.size != 1 then
+ printf("usage: #{$0} file\n");
+ exit
+ end
+
+ viewer = FileViewer.new(ARGV[0])
+end