unikernel/duniverse/ohex/ohex.ml

@@ -0,0 +1,121 @@
+
+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"