Add detection for generated PostScript files.

lib/linguist/generated.rb

@@ -57,6 +57,7 @@ module Linguist
         xcode_project_file? ||
         generated_net_docfile? ||
         generated_parser? ||
+        generated_postscript? ||
         generated_protocol_buffer?
     end
 
@@ -160,6 +161,29 @@ module Linguist
       false
     end
 
+    # Internal: Is the blob of PostScript generated?
+    #
+    # PostScript files are often generated by other programs. If they tell us so,
+    # we can detect them.
+    #
+    # Returns true or false.
+    def generated_postscript?
+      return false unless ['.ps', '.eps'].include? extname
+
+      # We analyze the "%%Creator:" comment, which contains the author/generator
+      # of the file. If there is one, it should be in one of the first few lines.
+      creator = lines[0..9].find {|line| line =~ /^%%Creator: /}
+      return false if creator.nil?
+
+      # Most generators write their version number, while human authors' or companies'
+      # names don't contain numbers. So look if the line contains digits. Also
+      # look for some special cases without version numbers.
+      return creator =~ /[0-9]/ ||
+        creator.include? "mpage" ||
+        creator.include? "draw" ||
+        creator.include? "ImageMagick"
+    end
+
     # Internal: Is the blob a C++, Java or Python source file generated by the
     # Protocol Buffer compiler?
     #

test/test_blob.rb

@@ -188,6 +188,9 @@ class TestBlob < Test::Unit::TestCase
     # PEG.js-generated parsers
     assert blob("JavaScript/parser.js").generated?
 
+    # Generated PostScript
+    assert !blob("PostScript/sierpinski.ps").generated?
+
     # These examples are too basic to tell
     assert !blob("JavaScript/empty.js").generated?
     assert !blob("JavaScript/hello.js").generated?