tool/jsmin.rb

   1 #!/usr/bin/ruby
   2 # jsmin.rb 2007-07-20
   3 # Author: Uladzislau Latynski
   4 # This work is a translation from C to Ruby of jsmin.c published by
   5 # Douglas Crockford.  Permission is hereby granted to use the Ruby
   6 # version under the same conditions as the jsmin.c on which it is
   7 # based.
   8 #
   9 # /* jsmin.c
  10 #    2003-04-21
  11 #
  12 # Copyright (c) 2002 Douglas Crockford  (www.crockford.com)
  13 #
  14 # Permission is hereby granted, free of charge, to any person obtaining a copy of
  15 # this software and associated documentation files (the "Software"), to deal in
  16 # the Software without restriction, including without limitation the rights to
  17 # use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
  18 # of the Software, and to permit persons to whom the Software is furnished to do
  19 # so, subject to the following conditions:
  20 #
  21 # The above copyright notice and this permission notice shall be included in all
  22 # copies or substantial portions of the Software.
  23 #
  24 # The Software shall be used for Good, not Evil.
  25 #
  26 # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  27 # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  28 # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  29 # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  30 # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  31 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  32 # SOFTWARE.
  33
  34 EOF = -1
  35 $theA = ""
  36 $theB = ""
  37
  38 # isAlphanum -- return true if the character is a letter, digit, underscore,
  39 # dollar sign, or non-ASCII character
  40 def isAlphanum(c)
  41    return false if !c || c == EOF
  42    return ((c >= 'a' && c <= 'z') || (c >= '0' && c <= '9') ||
  43            (c >= 'A' && c <= 'Z') || c == '_' || c == '$' ||
  44            c == '\\' || c[0] > 126)
  45 end
  46
  47 # get -- return the next character from stdin. Watch out for lookahead. If
  48 # the character is a control character, translate it to a space or linefeed.
  49 def get()
  50   c = $stdin.getc
  51   return EOF if(!c)
  52   c = c.chr
  53   return c if (c >= " " || c == "\n" || c.unpack("c") == EOF)
  54   return "\n" if (c == "\r")
  55   return " "
  56 end
  57
  58 # Get the next character without getting it.
  59 def peek()
  60     lookaheadChar = $stdin.getc
  61     $stdin.ungetc(lookaheadChar)
  62     return lookaheadChar.chr
  63 end
  64
  65 # mynext -- get the next character, excluding comments.
  66 # peek() is used to see if a '/' is followed by a '/' or '*'.
  67 def mynext()
  68     c = get
  69     if (c == "/")
  70         if(peek == "/")
  71             while(true)
  72                 c = get
  73                 if (c <= "\n")
  74                 return c
  75                 end
  76             end
  77         end
  78         if(peek == "*")
  79             get
  80             while(true)
  81                 case get
  82                 when "*"
  83                    if (peek == "/")
  84                         get
  85                         return " "
  86                     end
  87                 when EOF
  88                     raise "Unterminated comment"
  89                 end
  90             end
  91         end
  92     end
  93     return c
  94 end
  95
  96
  97 # action -- do something! What you do is determined by the argument: 1
  98 # Output A. Copy B to A. Get the next B. 2 Copy B to A. Get the next B.
  99 # (Delete A). 3 Get the next B. (Delete B). action treats a string as a
 100 # single character. Wow! action recognizes a regular expression if it is
 101 # preceded by ( or , or =.
 102 def action(a)
 103     if(a==1)
 104         $stdout.write $theA
 105     end
 106     if(a==1 || a==2)
 107         $theA = $theB
 108         if ($theA == "\'" || $theA == "\"")
 109             while (true)
 110                 $stdout.write $theA
 111                 $theA = get
 112                 break if ($theA == $theB)
 113                 raise "Unterminated string literal" if ($theA <= "\n")
 114                 if ($theA == "\\")
 115                     $stdout.write $theA
 116                     $theA = get
 117                 end
 118             end
 119         end
 120     end
 121     if(a==1 || a==2 || a==3)
 122         $theB = mynext
 123         if ($theB == "/" && ($theA == "(" || $theA == "," || $theA == "=" ||
 124                              $theA == ":" || $theA == "[" || $theA == "!" ||
 125                              $theA == "&" || $theA == "|" || $theA == "?" ||
 126                              $theA == "{" || $theA == "}" || $theA == ";" ||
 127                              $theA == "\n"))
 128             $stdout.write $theA
 129             $stdout.write $theB
 130             while (true)
 131                 $theA = get
 132                 if ($theA == "/")
 133                     break
 134                 elsif ($theA == "\\")
 135                     $stdout.write $theA
 136                     $theA = get
 137                 elsif ($theA <= "\n")
 138                     raise "Unterminated RegExp Literal"
 139                 end
 140                 $stdout.write $theA
 141             end
 142             $theB = mynext
 143         end
 144     end
 145 end
 146
 147 # jsmin -- Copy the input to the output, deleting the characters which are
 148 # insignificant to JavaScript. Comments will be removed. Tabs will be
 149 # replaced with spaces. Carriage returns will be replaced with linefeeds.
 150 # Most spaces and linefeeds will be removed.
 151 def jsmin
 152     $theA = "\n"
 153     action(3)
 154     while ($theA != EOF)
 155         case $theA
 156         when " "
 157             if (isAlphanum($theB))
 158                 action(1)
 159             else
 160                 action(2)
 161             end
 162         when "\n"
 163             case ($theB)
 164             when "{","[","(","+","-"
 165                 action(1)
 166             when " "
 167                 action(3)
 168             else
 169                 if (isAlphanum($theB))
 170                     action(1)
 171                 else
 172                     action(2)
 173                 end
 174             end
 175         else
 176             case ($theB)
 177             when " "
 178                 if (isAlphanum($theA))
 179                     action(1)
 180                 else
 181                     action(3)
 182                 end
 183             when "\n"
 184                 case ($theA)
 185                 when "}","]",")","+","-","\"","\\", "'", '"'
 186                     action(1)
 187                 else
 188                     if (isAlphanum($theA))
 189                         action(1)
 190                     else
 191                         action(3)
 192                     end
 193                 end
 194             else
 195                 action(1)
 196             end
 197         end
 198     end
 199 end
 200
 201 ARGV.each do |anArg|
 202     $stdout.write "// #{anArg}\n"
 203 end
 204
 205 jsmin