39 lines
990 B
Text
39 lines
990 B
Text
let greatest = List.fold_left max 0 ;;
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(** number of bits needed to encode the integer m *)
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let n_bits m =
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let m = float m in
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let rec aux n =
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let max = (2. ** n) -. 1. in
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if max >= m then int_of_float n
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else aux (n +. 1.0)
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in
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aux 1.0
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;;
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let write_compressed ~filename ~compressed =
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let nbits = n_bits(greatest compressed) in
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let oc = open_out filename in
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output_byte oc nbits;
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let ob = IO.output_bits(IO.output_channel oc) in
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List.iter (IO.write_bits ob nbits) compressed;
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IO.flush_bits ob;
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close_out oc;
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;;
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let read_compressed ~filename =
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let ic = open_in filename in
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let nbits = input_byte ic in
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let ib = IO.input_bits(IO.input_channel ic) in
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let rec loop acc =
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try
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let code = IO.read_bits ib nbits in
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loop (code::acc)
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with _ -> List.rev acc
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in
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let compressed = loop [] in
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let result = decompress ~compressed in
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let buf = Buffer.create 2048 in
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List.iter (Buffer.add_string buf) result;
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(Buffer.contents buf)
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;;
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