(* re2ocaml $INPUT -o $OUTPUT *)
open Bytes
%{max %}
let bufsize = 4096
exception Fill
type state = {
file: in_channel;
yyinput: bytes;
mutable yycursor: int;
mutable yymarker: int;
mutable yylimit: int;
mutable token: int;
mutable eof: bool;
}
type status = Ok | Eof | LongLexeme
let fill (st: state) (need: int) : status =
if st.eof then Eof else
(* Error: lexeme too long. In real life could reallocate a larger buffer. *)
if st.token < need then LongLexeme else (
(* Shift buffer contents (discard everything up to the current token). *)
blit st.yyinput st.token st.yyinput 0 (st.yylimit - st.token);
st.yycursor <- st.yycursor - st.token;
st.yymarker <- st.yymarker - st.token;
st.yylimit <- st.yylimit - st.token;
st.token <- 0;
(* Fill free space at the end of buffer with new data from file. *)
let n = input st.file st.yyinput st.yylimit (bufsize - st.yylimit - 1) in (* -1 for sentinel *)
re2c version: 4.1~8baaca577
Select example "ocaml/fill/02_fill.re"