62 lines
2.8 KiB
OCaml
62 lines
2.8 KiB
OCaml
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(**************************************************************************)
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(* *)
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(* Copyright (c) 2014 - 2016. *)
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(* Dynamic Ledger Solutions, Inc. <contact@tezos.com> *)
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(* *)
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(* All rights reserved. No warranty, explicit or implicit, provided. *)
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(* *)
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(**************************************************************************)
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(** A simple, portable implementation of network frames. *)
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(** The type of a single datum in a network frame. The encoding of a
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datum is as follows: [[TYPE][CONTENTS]], where [[type]] is a
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single byte whose value is [1] for [S], [2] for [I], [3] for [L],
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[4] for B, [5] for [D], [6] for [F] and [7] for [C].
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For [S]. [I], [L] and [D]¸ the raw values are stored using big
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endianness. For [B], [F] and [C], the size is prefixed as a 16-bit,
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big endian, unsigned integer
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([[SIZE][BYTES]]). *)
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type chunk =
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| S of int (** A 16-bit integer *)
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| I of int32 (** A 32-bit integer *)
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| L of int64 (** A 64-bit integer *)
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| B of MBytes.t (** A series of bytes *)
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| D of float (** A 64-bits IEEE-754 floating point number *)
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| F of frame (** An encapsulated subframe *)
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| C of string (** A string *)
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(** A network frame is a list of simple data. Its encoding on the
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network is as follows: [[SIZE][DATA]] where [[SIZE]] is the raw
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length of [[DATA]] in bytes as a big endian, 32-bit, unsigned
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integer. *)
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and frame =
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chunk list
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(** Writes a frame from to file descriptor Returns [true] if
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successful, [false] if an error happened, which means that the
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descriptor cannot accept any more data and should be closed. *)
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val write : Lwt_unix.file_descr -> frame -> bool Lwt.t
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(** Reads a frame from a file descriptor. Returns [Some frame] if
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successful, [None] if an error happened, which means either that
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that the descriptor cannot provide any more data or that corrupted
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bytes have been received, and in any case says that the descriptor
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should not be used anymore. The second parameter is the limit in
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bytes of the underlying representation, including the size. [None]
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is returned in case of overhead, and the bytes are not consumed
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from the descriptor. *)
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val read : Lwt_unix.file_descr -> int -> frame option Lwt.t
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(** Pretty printing of frames for debugging *)
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val print : Format.formatter -> frame -> unit
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(** Pretty prints of frames *)
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val to_string : frame -> string
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(** Encode a frame as raw bytes to send over the network *)
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val to_raw : frame -> MBytes.t
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(** Decode a complete raw frame as read from the network *)
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val of_raw : MBytes.t -> frame option
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