lisr.rb

gistfile1.ru

#!/usr/local/bin/ruby1.9 -w
#list.rb 
#Sean Stephenson
#2009-09-24
#CS 177
#takes as input a file and options to display
#specific lines and [correspding line number]


### usage ###

def usage
  abort "usage: [-n] [ [0-9],[-],[$] file_name"
end

### getMaxLine ###

def getMaxLine
  file = File.open($file)
  fileArray = Array.new
  i = 0
  while(file.eof == false)
    fileArray[i] = file.readline
    i += 1
  end
  return fileArray
end

### calcMaxLine ###

def calcMaxLine(range)
  lastLine = 0
  val = range.split ","
  val.each do |i|
    case
      when i =~ /([0-9])(\-)([0-9])/ #(1) (num) dash (num)
        value = i.split "-"
        lastLine = value[0].to_i if value[0].to_i > lastLine
        lastLine = value[1].to_i if value[1].to_i > lastLine
      when i =~ /([0-9])(\-)/ #(2) (num) dash
        return getMaxLine   
      when i =~ /(\-)([0-9])/ #(3) dash (num)
        value = i.split "-"
        lastLine = value[1].to_i if value[1].to_i > lastLine
      when i =~ /([0-9])/ #(4) number
        lastLine = i.to_i if i.to_i > lastLine
      else  #(5) dash
        return getMaxLine
    end
  end
  file = File.open($file)
  fileArray = Array.new
  i = 0
  while(i < lastLine)    
    if file.eof == true
       abort "there are only " + (i + 1).to_s + " lines in the file."
    end    
    fileArray[i] = file.readline 
    i += 1
  end
  return fileArray  
end

### parseNum ###

def parseNum(range)  
  abort usage if range =~ /[^\d,^\$,^\-,^\,]/
  if range =~ /\$/
    fileLines = getMaxLine
    maxLine = fileLines.size
  else
    fileLines = calcMaxLine(range)
    maxLine = fileLines.size + 1
  end
  val = range.split "," 
  val.each do |i|
    case
      when i =~ /([0-9]|\$)(\-)([0-9]|\$)/ ### 1. (num|$) dash (num|$)      
        value = i.split "-"
        if value[0] =~ /\$/
          line_a = maxLine
        else
          line_a = value[0].to_i
        end        
        if value[1] =~ /\$/
          line_b = maxLine
        else
          line_b = value[1].to_i
        end                        
        line_a -= 1
        if line_a < line_b
          while (line_a < line_b)
            if $printLineNums == false
              puts fileLines[line_a].to_s
            else
              line_no = line_a + 1
              print line_no.to_s + ": " ; print fileLines[line_a]
            end
            line_a += 1
          end          
        else
          while (line_b-1 <= line_a)
            if $printLineNums == false
              puts fileLines[line_a].to_s
            else
              line_no = line_a + 1
              print line_no.to_s + ": " ; print fileLines[line_a]
            end
            line_a -= 1
          end
        end                     
      when i =~ /([0-9]|\$)(\-)/ ### 2. (num|$) dash
        value = i.split "-"
        line_a = value[0].to_i - 1
        while (line_a < maxLine)
          if $printLineNums == false
            puts fileLines[line_a]
          else
            line_no = line_a + 1
            print line_no.to_s + ": " ; print fileLines[line_a]          
          end
          line_a += 1
        end       
      when i=~  /(\-)([0-9]|\$)/ ### 3. dash (num|$)
        value = i.split "-" 
        if value[1] =~ /\$/
          line_a = maxLine - 1
        else
          line_a = value[1].to_i - 1
        end
        counter = 0
        if $printLineNums == false
          while (counter <= line_a)
            puts fileLines[counter]
            counter += 1
          end
        else
          while (counter <= line_a)
            line_no = counter + 1
            puts line_no.to_s + ": " + fileLines[counter].to_s
            counter += 1
          end        
        end
      when i =~ /[0-9]/ ; ### 4. number          
        if $printLineNums == false
          puts fileLines[(i.to_i - 1)]
        else
          puts i + ": " + fileLines[(i.to_i - 1)]
        end  
      else ### 5. dollar or dash
        if $printLineNums == false
         puts fileLines         
        else
          counter = 1
          while (counter <= fileLines.size)          
            puts counter.to_s + ": " + fileLines[counter-1]
            counter += 1
          end
        end
    end
  end
end
#take args and rip it
if ARGV.length > 3
  abort usage
end

if ARGV. length == 0
  abort usage
end
# one ARG
if ARGV.length == 1
  if File.exist?(ARGV[0])
    File.open(ARGV[0]) do |f|
      while line = f.gets
        puts line
      end
    end
  else
    abort usage
  end
end
# two ARGS
if ARGV.length == 2
  if ARGV[0] == "-n"
		if File.exist?(ARGV[1])
		  File.open(ARGV[1]) do |f|
        counter = 1
		    while line = f.gets
		      puts counter.to_s + ": " + line
		      counter += 1
		    end
		  end
		else
		  abort usage
		end
  else
    $file = File.open(ARGV[1])
    $printLineNums = false
    parseNum(ARGV[0])  
  end  
end
# three ARGS
if ARGV.length == 3
  abort usage if File.exist?(ARGV[2]) == false
  $file = File.open(ARGV[2])
  $printLineNums = true
  parseNum(ARGV[1])
end