nv-buf-utf8

nv-buf-utf8
===============
- nv-buf-utf8
- a utf8 step-decoder, input one-byte each time. return-code-point-if-success , return-undefined-if-in-waiting-more-bytes
- support two-modes: auto-recover AND throw-error
- can observe state : [ 'INIT', 'U1', 'U2', 'U3', 'U4', 'ERROR' ]
- its for remote decode , normally USELESS

install
=======
- npm install nv-buf-utf8

usage
=====

const {decd} = require("nv-buf-utf8");
const {Mach} = decd.mach;

example
-------

var mach = new Mach()

var buf = Buffer.from("我你");
/*
> "我".codePointAt(0)
25105
> "你".codePointAt(0)
20320
>
*/

> mach.input(buf[0])
undefined
> mach.input(buf[1])
undefined
> mach
Mach(7) [{"cursor":5,"state":"U3","data":[230,136],"err_byte":0}] [
5, 19, 0, 230,
136, 0, 0
]
> mach.input(buf[2])
25105
>
> mach
Mach(7) [{"cursor":3,"state":"INIT","data":[],"err_byte":0}] [
3, 16, 0, 0,
0, 0, 0
]
>
> mach.input(buf[3])
undefined
> mach.input(buf[4])
undefined
> mach.input(buf[5])
20320
>
> mach.input(buf[0])
undefined
> mach
Mach(7) [{"cursor":4,"state":"U3","data":[230],"err_byte":0}] [
4, 19, 0, 230,
0, 0, 0
]
> mach.lefted_
[ 230 ]
> mach.input(buf[1])
undefined
> mach.lefted_
[ 230, 136 ]
> mach.input(buf[2])
25105
> mach.lefted_
[]
>

METHODS
=======

decode
------

decd.mach.mach.cursor_ decd.mach.mach.dict
decd.mach.mach.disable_auto_recover decd.mach.mach.enable_auto_recover decd.mach.mach.err_byte_
decd.mach.mach.input decd.mach.mach.is_auto_recover_enabled decd.mach.mach.is_err
decd.mach.mach.is_init decd.mach.mach.is_u2 decd.mach.mach.is_u3
decd.mach.mach.is_u4 decd.mach.mach.lefted_ decd.mach.mach.reset
decd.mach.mach.state_code_ decd.mach.mach.state_name_

mach: {
STATES: [ 'INIT', 'U1', 'U2', 'U3', 'U4', 'ERROR' ],
ERRORS: {
in_error_must_reset: 'in_error_must_reset',
fst_byte_invalid: 'first byte must be <0xxxxxxx> OR <110xxxxx> OR <1110xxxx> OR <11110xxx>',
follow_byte_invalid: 'follow byte must be <10xxxxxx>'
},
Mach: [class Mach extends Uint8Array] { ALGN_OFFSET: 3 },
auto_recover_mach: Mach(7) [{"cursor":3,"state":"INIT","data":[],"err_byte":0}] [
3, 16, 0, 0,
0, 0, 0
],
mach: Mach(7) [{"cursor":3,"state":"INIT","data":[],"err_byte":0}] [
3, 0, 0, 0,
0, 0, 0
]
}

API
====

decode
------

> decd.def
{
is_u1_head: [Function: is_u1_head],
is_u2_head: [Function: is_u2_head],
is_u3_head: [Function: is_u3_head],
is_u4_head: [Function: is_u4_head],
is_follow: [Function: is_follow],
u2_to_code: [Function: u2_to_code],
u3_to_code: [Function: u3_to_code],
u4_to_code: [Function: u4_to_code],
barr_to_code: [Function: barr_to_code]
}
>

LICENSE
=======
- ISC