lib/filter_stream.nit

   1 # This file is part of NIT ( http://www.nitlanguage.org ).
   2 #
   3 # Copyright 2006 Floréal Morandat <morandat@lirmm.fr>
   4 #
   5 # This file is free software, which comes along with NIT.  This software is
   6 # distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
   7 # without  even  the implied warranty of  MERCHANTABILITY or  FITNESS FOR A
   8 # PARTICULAR PURPOSE.  You can modify it is you want,  provided this header
   9 # is kept unaltered, and a notification of the changes is added.
  10 # You  are  allowed  to  redistribute it and sell it, alone or is a part of
  11 # another product.
  12
  13 class FilterIStream
  14 special IStream
  15         # Filter readed elements
  16         readable attr _stream: IStream
  17
  18         redef meth eof: Bool
  19         do
  20                 assert stream != null
  21                 return stream.eof
  22         end
  23
  24         private meth stream=(i: IStream)
  25         do
  26                 _stream = i
  27         end
  28 end
  29
  30 class FilterOStream
  31 special OStream
  32         # Filter outputed elements
  33         readable attr _stream: OStream
  34
  35         # Can the stream be used to write
  36         redef meth is_writable: Bool
  37         do
  38                 assert stream != null
  39                 return stream.is_writable
  40         end
  41
  42         private meth stream=(i: OStream)
  43         do
  44                 _stream = i
  45         end
  46 end
  47
  48 class StreamCat
  49 special FilterIStream
  50         attr _streams: Iterator[IStream]
  51
  52         redef meth eof: Bool
  53         do
  54                 if stream == null then
  55                         return true
  56                 else if stream.eof then
  57                         stream.close
  58                         stream = null
  59                         return eof
  60                 else
  61                         return false
  62                 end
  63         end
  64
  65         redef meth stream: IStream
  66         do
  67                 if _stream == null and _streams.is_ok then
  68                         stream = _streams.item
  69                         assert _stream != null
  70                         _streams.next
  71                 end
  72                 return _stream
  73         end
  74
  75         redef meth read_char: Int
  76         do
  77                 assert not eof
  78                 return stream.read_char
  79         end
  80
  81         redef meth close
  82         do
  83                 while stream != null do
  84                         stream.close
  85                         stream = null
  86                 end
  87         end
  88
  89         init with_streams(streams: Array[IStream])
  90         do
  91                 _streams = streams.iterator
  92         end
  93         init(streams: IStream ...)
  94         do
  95                 _streams = streams.iterator
  96         end
  97 end
  98
  99 class StreamDemux
 100 special FilterOStream
 101         attr _streams: Array[OStream]
 102
 103         redef meth is_writable: Bool
 104         do
 105                 if stream.is_writable then
 106                         return true
 107                 else
 108                         for i in _streams
 109                         do
 110                                 if i.is_writable then
 111                                         return true
 112                                 end
 113                         end
 114                         return false
 115                 end
 116         end
 117
 118         redef meth write(s: String)
 119         do
 120                 for i in _streams
 121                 do
 122                         stream = i
 123                         if stream.is_writable then
 124                                 stream.write(s)
 125                         end
 126                 end
 127         end
 128
 129         init with_streams(streams: Array[OStream])
 130         do
 131                 _streams = streams
 132         end
 133
 134         init(streams: OStream ...)
 135         do
 136                 _streams = streams
 137         end
 138 end