---------------------------------------------------------------------------- 
  *   Copyright ( c ) 2017 Inhabited Type LLC . 

  *   All rights reserved . 

  *   Redistribution and use in source and binary forms , with or without 
  *   modification , are permitted provided that the following conditions 
  *   are met : 

  *   1 . Redistributions of source code must retain the above copyright 
  *      notice , this list of conditions and the following disclaimer . 

  *   2 . Redistributions in binary form must reproduce the above copyright 
  *      notice , this list of conditions and the following disclaimer in the 
  *      documentation and/or other materials provided with the distribution . 

  *   3 . Neither the name of the author nor the names of his contributors 
  *      may be used to endorse or promote products derived from this software 
  *      without specific prior written permission . 

  *   THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS ` ` AS IS '' AND ANY EXPRESS 
  *   OR IMPLIED WARRANTIES , INCLUDING , BUT NOT LIMITED TO , THE IMPLIED 
  *   WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 
  *   DISCLAIMED .   IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE FOR 
  *   ANY DIRECT , INDIRECT , INCIDENTAL , SPECIAL , EXEMPLARY , OR CONSEQUENTIAL 
  *   DAMAGES ( INCLUDING , BUT NOT LIMITED TO , PROCUREMENT OF SUBSTITUTE GOODS 
  *   OR SERVICES ; LOSS OF USE , DATA , OR PROFITS ; OR BUSINESS INTERRUPTION ) 
  *   HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY , WHETHER IN CONTRACT , 
  *   STRICT LIABILITY , OR TORT ( INCLUDING NEGLIGENCE OR OTHERWISE ) ARISING IN 
  *   ANY WAY OUT OF THE USE OF THIS SOFTWARE , EVEN IF ADVISED OF THE 
  *   POSSIBILITY OF SUCH DAMAGE . 
  * ----------------------------------------------------------------------------
 *  Copyright (c) 2017 Inhabited Type LLC.

 *  All rights reserved.

 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions
 *  are met:

 *  1. Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.

 *  2. Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.

 *  3. Neither the name of the author nor the names of his contributors
 *     may be used to endorse or promote products derived from this software
 *     without specific prior written permission.

 *  THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS ``AS IS'' AND ANY EXPRESS
 *  OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 *  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 *  DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE FOR
 *  ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 *  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 *  OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 *  HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 *  STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 *  ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 *  POSSIBILITY OF SUCH DAMAGE.
 *----------------------------------------------------------------------------*)

type 'a t = 'a Faraday.iovec =
  { buffer : 'a
  ; off : int
  ; len : int
  }

let length { len; _ } = len

let lengthv iovs = List.fold_left (fun acc { len; _ } -> acc + len) 0 iovs

let shift { buffer; off; len } n =
  assert (n <= len);
  { buffer; off = off + n; len = len - n }

let shiftv iovecs n =
  if n < 0 then
    failwith (Printf.sprintf "IOVec.shiftv: %d is a negative number" n);
  let rec loop iovecs n =
    if n = 0 then
      iovecs
    else
      match iovecs with
      | [] ->
        failwith "shiftv: n > lengthv iovecs"
      | iovec :: iovecs ->
        let iovec_len = length iovec in
        if iovec_len <= n then
          loop iovecs (n - iovec_len)
        else
          shift iovec n :: iovecs
  in
  loop iovecs n

let add_len { buffer; off; len } n = { buffer; off; len = len + n }

let pp_hum fmt t =
  Format.fprintf fmt "{ buffer = <opaque>; off = %d; len = %d }" t.off t.len

---------------------------------------------------------------------------- 
  *   Copyright ( c ) 2017 Inhabited Type LLC . 

  *   All rights reserved . 

  *   Redistribution and use in source and binary forms , with or without 
  *   modification , are permitted provided that the following conditions 
  *   are met : 

  *   1 . Redistributions of source code must retain the above copyright 
  *      notice , this list of conditions and the following disclaimer . 

  *   2 . Redistributions in binary form must reproduce the above copyright 
  *      notice , this list of conditions and the following disclaimer in the 
  *      documentation and/or other materials provided with the distribution . 

  *   3 . Neither the name of the author nor the names of his contributors 
  *      may be used to endorse or promote products derived from this software 
  *      without specific prior written permission . 

  *   THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS ` ` AS IS '' AND ANY EXPRESS 
  *   OR IMPLIED WARRANTIES , INCLUDING , BUT NOT LIMITED TO , THE IMPLIED 
  *   WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 
  *   DISCLAIMED .   IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE FOR 
  *   ANY DIRECT , INDIRECT , INCIDENTAL , SPECIAL , EXEMPLARY , OR CONSEQUENTIAL 
  *   DAMAGES ( INCLUDING , BUT NOT LIMITED TO , PROCUREMENT OF SUBSTITUTE GOODS 
  *   OR SERVICES ; LOSS OF USE , DATA , OR PROFITS ; OR BUSINESS INTERRUPTION ) 
  *   HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY , WHETHER IN CONTRACT , 
  *   STRICT LIABILITY , OR TORT ( INCLUDING NEGLIGENCE OR OTHERWISE ) ARISING IN 
  *   ANY WAY OUT OF THE USE OF THIS SOFTWARE , EVEN IF ADVISED OF THE 
  *   POSSIBILITY OF SUCH DAMAGE . 
  * ----------------------------------------------------------------------------
 *  Copyright (c) 2017 Inhabited Type LLC.

 *  All rights reserved.

 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions
 *  are met:

 *  1. Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.

 *  2. Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.

 *  3. Neither the name of the author nor the names of his contributors
 *     may be used to endorse or promote products derived from this software
 *     without specific prior written permission.

 *  THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS ``AS IS'' AND ANY EXPRESS
 *  OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 *  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 *  DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE FOR
 *  ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 *  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 *  OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 *  HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 *  STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 *  ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 *  POSSIBILITY OF SUCH DAMAGE.
 *----------------------------------------------------------------------------*)

type 'a t = 'a Faraday.iovec =
  { buffer : 'a
  ; off : int
  ; len : int
  }

let length { len; _ } = len

let lengthv iovs = List.fold_left (fun acc { len; _ } -> acc + len) 0 iovs

let shift { buffer; off; len } n =
  assert (n <= len);
  { buffer; off = off + n; len = len - n }

let shiftv iovecs n =
  if n < 0 then
    failwith (Printf.sprintf "IOVec.shiftv: %d is a negative number" n);
  let rec loop iovecs n =
    if n = 0 then
      iovecs
    else
      match iovecs with
      | [] ->
        failwith "shiftv: n > lengthv iovecs"
      | iovec :: iovecs ->
        let iovec_len = length iovec in
        if iovec_len <= n then
          loop iovecs (n - iovec_len)
        else
          shift iovec n :: iovecs
  in
  loop iovecs n

let add_len { buffer; off; len } n = { buffer; off; len = len + n }

let pp_hum fmt t =
  Format.fprintf fmt "{ buffer = <opaque>; off = %d; len = %d }" t.off t.len
