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