CCSDS 121.0-B-3 Lossless Data Compression (Rice/Golomb coding)
Credit Daniel Bünzli's jsont soup paper in all *t codec libraries
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test/debug/debug.ml
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test/debug/debug.ml
···
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let block_size = 16 in
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let bits_per_sample = 16 in
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let count = block_size * 4 in
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Printf.printf "Testing constant 42, bs=%d, bps=%d, count=%d\n%!" block_size
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bits_per_sample count;
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(* Generate constant data *)
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let bps_bytes = (bits_per_sample + 7) / 8 in
···
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(* Compress with libaec *)
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let libaec_compressed = libaec_encode raw_data block_size bits_per_sample in
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Printf.printf "libaec compressed: %d bytes\n%!"
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(Bytes.length libaec_compressed);
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Printf.printf "bytes: ";
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Printf.printf "libaec compressed: %d bytes: " (Bytes.length libaec_compressed);
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for i = 0 to Bytes.length libaec_compressed - 1 do
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Printf.printf "%02x " (Bytes.get_uint8 libaec_compressed i)
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done;
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Printf.printf "\n%!";
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(* Also compress with rice *)
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Printf.printf "Attempting rice decompress...\n%!";
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let cfg = Rice.config ~block_size ~bits_per_sample () in
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let rice_compressed = Rice.compress cfg raw_data in
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Printf.printf "rice compressed: %d bytes\n%!" (Bytes.length rice_compressed);
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Printf.printf "bytes: ";
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for i = 0 to Bytes.length rice_compressed - 1 do
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Printf.printf "%02x " (Bytes.get_uint8 rice_compressed i)
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done;
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Printf.printf "\n%!";
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(* Verify libaec can decompress our output *)
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Printf.printf "Attempting libaec decompress of rice data...\n%!";
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(try
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let result =
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libaec_decode rice_compressed block_size bits_per_sample
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(Bytes.length raw_data)
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in
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if Bytes.equal result raw_data then
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Printf.printf "libaec decompressed rice: MATCH!\n%!"
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else Printf.printf "libaec decompressed rice: MISMATCH\n%!"
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with exn -> Printf.printf "Exception: %s\n%!" (Printexc.to_string exn));
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Printf.printf "Done\n%!"
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try
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match Rice.decompress ~sample_count:count cfg libaec_compressed with
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| Ok r ->
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Printf.printf "OK: %d bytes\n%!" (Bytes.length r);
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if Bytes.equal r raw_data then Printf.printf "MATCH!\n%!"
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else begin
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Printf.printf "MISMATCH. First few bytes:\nExpected: ";
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for i = 0 to min 15 (Bytes.length raw_data - 1) do
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Printf.printf "%02x " (Bytes.get_uint8 raw_data i)
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done;
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Printf.printf "\nGot: ";
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for i = 0 to min 15 (Bytes.length r - 1) do
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Printf.printf "%02x " (Bytes.get_uint8 r i)
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done;
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Printf.printf "\n%!"
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end
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| Error e -> Printf.printf "Error: %s\n%!" e
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with exn ->
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Printf.printf "Exception: %s\n%!" (Printexc.to_string exn);
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Printexc.print_backtrace stdout;
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flush stdout