111 lines
3.2 KiB
OCaml
111 lines
3.2 KiB
OCaml
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let string_fold f acc str =
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let st = ref acc in
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String.iter (fun c -> st := f !st c) str;
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!st
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let is_space = function
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| ' ' | '\n' | '\r' | '\t' -> true
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| _ -> false
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let digit = function
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| '0'..'9' as c -> int_of_char c - 0x30
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| 'A'..'F' as c -> int_of_char c - 0x41 + 10
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| 'a'..'f' as c -> int_of_char c - 0x61 + 10
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| _ -> invalid_arg "bad character"
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let required_length ?(skip_whitespace = true) src =
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let req =
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string_fold (fun r c ->
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if skip_whitespace && is_space c then
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r
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else (
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ignore (digit c);
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succ r))
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0 src
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in
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if req mod 2 = 0 then
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req / 2
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else
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invalid_arg "leftover byte in hex string"
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let decode_into ?(skip_whitespace = true) src tgt ?(off = 0) () =
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let fold f acc str =
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let st = ref acc in
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String.iter (fun c -> st := f !st c) str;
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!st
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in
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let chars, leftover =
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fold (fun (chars, leftover) c ->
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if skip_whitespace && is_space c then
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chars, leftover
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else
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let c = digit c in
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match leftover with
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| None -> chars, Some (c lsl 4)
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| Some c' -> (c' lor c) :: chars, None)
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([], None) src
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in
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let chars = List.rev chars in
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if leftover <> None then
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invalid_arg "leftover byte in hex string";
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List.iteri (fun idx c -> Bytes.set_uint8 tgt (off + idx) c) chars
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let decode ?(skip_whitespace = true) src =
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let len = required_length ~skip_whitespace src in
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let buf = Bytes.create len in
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decode_into ~skip_whitespace src buf ();
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Bytes.unsafe_to_string buf
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let hex_map = "0123456789abcdef"
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let encode_into src tgt ?(off = 0) () =
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String.iteri (fun idx c ->
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let hi, lo =
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let i = int_of_char c in
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hex_map.[i lsr 4], hex_map.[i land 0x0F]
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in
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Bytes.set tgt (idx * 2 + off) hi;
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Bytes.set tgt (idx * 2 + off + 1) lo)
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src
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let encode src =
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let buf = Bytes.create (String.length src * 2) in
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encode_into src buf ();
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Bytes.unsafe_to_string buf
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let printable_ascii c =
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let i = int_of_char c in
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not (i < 0x20 || i >= 0x7f)
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let pp ?(row_numbers = true) ?(chars = true) () ppf s =
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String.iteri (fun idx c ->
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if idx mod 16 = 0 && row_numbers then
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Format.fprintf ppf "%06x " idx;
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Format.fprintf ppf "%02x" (int_of_char c);
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if idx mod 2 = 1 then
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Format.pp_print_string ppf " ";
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if idx mod 8 = 7 then
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Format.pp_print_string ppf " ";
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if idx mod 16 = 15 && chars then
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String.iter (fun c ->
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Format.pp_print_char ppf (if printable_ascii c then c else '.'))
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(String.sub s (idx - 15) 16);
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if idx mod 16 = 15 then
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Format.pp_print_string ppf "\n")
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s;
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(if chars then
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let last_n, pad =
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let l = String.length s in
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let pad = 16 - (l mod 16) in
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let pad = if pad = 16 then 0 else pad in
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String.sub s (l - (l mod 16)) (l mod 16),
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pad
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in
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let pad_chars = pad * 2 + (pad + 1) / 2 + (if pad > 8 then 1 else 0) + 1 in
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Format.pp_print_string ppf (String.make pad_chars ' ');
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String.iter (fun c ->
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Format.pp_print_char ppf (if printable_ascii c then c else '.'))
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last_n);
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if String.length s mod 16 <> 0 then
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Format.pp_print_string ppf "\n"
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