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type encoder =
{ payload : Bytes.t
; mutable pos : int }
let pp ppf _t = Fmt.string ppf "#encoder"
type error = [ `Not_enough_space ]
let pp_error ppf `Not_enough_space = Fmt.string ppf "No enough space"
type 'err state =
| Write of { buffer : string
; off : int
; len : int
; continue : int -> 'err state }
| Error of 'err
| Done
let io_buffer_size = 65536
let encoder () =
{ payload= Bytes.create io_buffer_size
; pos= 0 }
exception Leave of error
let leave_with (_ : encoder) error =
raise (Leave error)
let safe
: (encoder -> ([> error ] as 'err) state) -> encoder -> 'err state
= fun k encoder ->
try k encoder
with Leave (#error as err) -> Error (err :> 'err)
let flush k0 encoder =
if encoder.pos > 0
then
let rec k1 n =
if n < encoder.pos
then Write { buffer= Bytes.unsafe_to_string encoder.payload
; off= n
; len= encoder.pos - n
; continue= (fun m -> k1 (n + m)) }
else ( encoder.pos <- 0 ; k0 encoder ) in
k1 0
else k0 encoder
let write s encoder =
let max = Bytes.length encoder.payload in
let go j l encoder =
let rem = max - encoder.pos in
let len = if l > rem then rem else l in
Bytes.blit_string s j encoder.payload encoder.pos len ;
encoder.pos <- encoder.pos + len ;
if len < l then leave_with encoder `Not_enough_space in
go 0 (String.length s) encoder
let blit ~buf ~off ~len encoder =
let max = Bytes.length encoder.payload in
let go j l encoder =
let rem = max - encoder.pos in
let len = if l > rem then rem else l in
Bytes.blit_string buf (off + j) encoder.payload encoder.pos len ;
encoder.pos <- encoder.pos + len ;
if len < l then leave_with encoder `Not_enough_space in
go 0 len encoder