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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 }
let encoder_from_preallocated_bytes payload = { payload; 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