38 lines
1.3 KiB
OCaml
38 lines
1.3 KiB
OCaml
open Types
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open Utils
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let parse_header reader =
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let max_size = 6 in
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match List.init max_size (fun offset -> unpack_short_be reader (offset * 2)) with
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| [ id; flags; num_questions; num_answers; num_authorities; num_additionals ] ->
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( bytes_forward reader (max_size * 2)
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, { id; flags; num_questions; num_answers; num_authorities; num_additionals } )
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| _ -> failwith "Invalid number of fields"
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;;
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let rec parse_question reader =
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let reader', name_b = decode_name_simple reader in
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let name = String.to_bytes name_b in
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let max_size = 2 in
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match List.init max_size (fun offset -> unpack_short_be reader' (offset * 2)) with
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| [ type_; class_ ] -> bytes_forward reader' (max_size * 2), { name; type_; class_ }
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| _ -> failwith "Invalid number of fields"
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and decode_name_simple reader =
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let rec read_parts parts pos =
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let length = int_of_char (Bytes.get reader pos) in
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if length = 0
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then 1, parts
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else (
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let part = Bytes.sub_string reader (pos + 1) length in
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let last_length, parts' = read_parts (parts @ [ part ]) (pos + 1 + length) in
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last_length + length + 1, parts')
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in
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let offset, parts = read_parts [] 0 in
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bytes_forward reader offset, String.concat "." parts
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;;
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let parse_record _reader =
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let name, type_, class_, ttl, data = Bytes.empty, 0, 0, 0, Bytes.empty in
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{ name; type_; class_; ttl; data }
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;;
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