Class: VNCRec::RFB::EncZRLE::Stream

Inherits:
Object
  • Object
show all
Defined in:
lib/vncrec/rfb/enczrle.rb

Instance Method Summary collapse

Constructor Details

#initialize(io, bitspp, depth) ⇒ Stream

Returns a new instance of Stream.



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# File 'lib/vncrec/rfb/enczrle.rb', line 8

def initialize(io,bitspp,depth)
  @io = io
  @zstream = Zlib::Inflate.new
  @bpp_orig = (bitspp.to_f/8.0).ceil
  @bpp = case bitspp
         when 32 then 
           @depth <= 24 ? 3 : 4
         when 8 then
           1
         else
           raise "Cannot handle such pixel format"
         end
  @depth = depth
end

Instance Method Details

#handle_ZRLE_packed_palette(stream, psize, tw = 64, th = 64) ⇒ Object 



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# File 'lib/vncrec/rfb/enczrle.rb', line 151

def handle_ZRLE_packed_palette(stream, psize, tw=64, th=64)
  pixels = Array.new(tw*th, 0)
  bitspp = case psize
           when 2 then 1
           when 3..4 then 2
           when 5..16 then 4
           else 
             return pixels
           end
  palette = []
  psize.times do
    palette << stream.read(@bpp).unpack("C*")
  end
  count = case psize
          when 2 then th*((tw+7)/8)
          when 3..4 then th*((tw+3)/4)
          when 5..16 then th*((tw+1)/2)
          end
  off_bits = 0
  bits_per_row = bitspp * tw
  padding_bits = bits_per_row % 8
  encoded_len_bits = 64 * (bits_per_row + padding_bits)
  encoded = stream.read(count).unpack("C*")
  pixnum = 0
  while off_bits < (encoded_len_bits - padding_bits - bitspp)
    b1 = encoded[off_bits/8]
    b2 = encoded[off_bits/8 + 1] || 0
    b1 <<= 8
    pixels[pixnum] = palette[h_bitmask(b2 + b1, bitspp, off_bits % 16)].pack("C*")
    off_bits += if (off_bits % bits_per_row) > (bits_per_row - padding_bits) and (padding_bits > 0)
                  bitspp + padding_bits
                else
                  bitspp
                end
    pixnum += 1
  end
  pixels
end

#handle_ZRLE_palette_RLE_tile(stream, psize, tw = 64, th = 64) ⇒ Object 



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# File 'lib/vncrec/rfb/enczrle.rb', line 92

def handle_ZRLE_palette_RLE_tile(stream,psize,tw=64,th=64)
  palette = []
  pixels = Array.new(tw*th)
  psize.times do
    palette << stream.read(@bpp)
  end
  len = 0
  begin
    while len < tw*th
      id = stream.read(1).unpack("C")[0]
      #
      #+--------+--------+--------+--------+
      #|   id   |   255  |   ..   |  <255  |
      #+--------+--------+--------+--------+
      #
      if (id & 0b10000000) == 0 
        rl = 1
      else
        id -= 128
        rl = 0
        rem = 0
        while (rem = stream.readbyte) == 255
          rl += 255
        end
        rl += rem + 1 
      end
      pixels[len...(len+rl)] = Array.new(rl, palette[id]) #TODO: if rl == 1 
      len += rl
    end
  rescue EOFError
  end
  pixels
end

#handle_ZRLE_plain_RLE_tile(stream, tw = 64, th = 64) ⇒ Object 



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# File 'lib/vncrec/rfb/enczrle.rb', line 126

def handle_ZRLE_plain_RLE_tile(stream,tw=64,th=64)
  pixels = Array.new(tw*th)
  len = 0
  begin
    while len < tw*th
      color = stream.read(@bpp)
      #
      #+--------+--------+--------+--------+
      #|  color |   255  |   ..   |  <255  |
      #+--------+--------+--------+--------+
      #
      rl = 0
      rem = 0
      while (rem = stream.readbyte) == 255
        rl += 255
      end
      rl += rem + 1 
      pixels[len...(len+rl)] = Array.new(rl, color) #TODO: if rl == 1 
      len += rl
    end
  rescue EOFError
  end
  pixels
end

#read_rect(w, h) ⇒ Object 



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# File 'lib/vncrec/rfb/enczrle.rb', line 35

def read_rect(w,h)
  fb = Array.new(w*h*@bpp)
  data = ""
  begin
    data = @zstream.inflate(read_zchunk)
  rescue Zlib::DataError
    return
  end

  stream = StringIO.new data

  tile_cols = (w.to_f/64).ceil
  tile_rows = (h.to_f/64).ceil
  tile_cols_rem = w % 64
  tile_rows_rem = h % 64

  tile_rows.times do |tile_row_num|
    tile_cols.times do |tile_col_num|
      th = if ((tile_row_num == tile_rows-1) and (tile_rows_rem > 0)) 
             tile_rows_rem
           else
             64
           end
      tw = if ((tile_col_num == tile_cols-1) and (tile_cols_rem > 0))
             tile_cols_rem 
           else
             64
           end

      subenc = stream.readbyte
      tile = case subenc
             when 0 then 		#Raw
               tile = Array.new(tw*th)
               th.times do
                 tile << (stream.read tw*@bpp_orig).unpack("C*").join
               end
               tile
             when 1 then 		#Solid
               Array.new(tw*th, stream.read(@bpp_orig))
             when 2..16 then 		#Packed palette
               handle_ZRLE_packed_palette(stream, subenc, tw,th)
             when 128 then 		#Plain RLE
               handle_ZRLE_plain_RLE_tile(stream,tw,th)
             when 130..255 then 	#RLE w/ palette
               handle_ZRLE_palette_RLE_tile(stream,subenc-128, tw,th)
             end

      th.times do |y|
        boline = (64 * tile_row_num + y) * w
        offx = 64 * tile_col_num
        fb[(boline+offx)...(boline+offx+tw)] = tile[(tw*y)...(tw*(y+1))]
      end
    end  #tile_col.times
  end#tile_row.times
  return fb.join
end

#read_zchunk ⇒ Object 



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# File 'lib/vncrec/rfb/enczrle.rb', line 23

def read_zchunk
  zdata_len = (@io.readpartial 4).unpack("L>")[0]
  zdata = ""
  to_read = zdata_len

  while zdata.size < zdata_len
    zdata += @io.read(to_read)
    to_read = zdata_len - zdata.size
  end
  return zdata
end