Introduction:

Lua binding for KCP, interface description written in lua-interface.md, see details of the project description within the KCP. what is KCP? please visit: https://github.com/skywind3000/kcp, http://www.skywind.me/blog/archives/1048

#Make: Just make

#Structure: ####3rd: lua: taken lua53 kcp: visit https://github.com/skywind3000/kcp

####src: lkcp.c: the file for bind kcp testkcp.lua: the file for test kcp

####run_test.sh: After the project compile successfully, you can run this file to test kcp

#lua-interface:

LKcp.lkcp_init(output)

DESCRIPTION

Init KCP layer.

PARAMETERS

output: a callback for KCP layer to invoke when send data to transport layer
[
    output prototype:
        function output(info, buf)
            ...
        end
    info is brought when invoke lkcp_create
    buf is to be sent
]

RETURN

ret: always 0

LKcp.lkcp_create(session, info)

DESCRIPTION

Create kcp object.

PARAMETERS

session: number mark session 
info: extra info, when KCP layer invoke callback to send data, KCP layer would brings that to output
[
    info prototype:
        info = {1, "who", ...}
    notice:
        the form of info must be sequential, and elements must be string or integer
]

RETURN

kcp: kcp object

kcp:lkcp_wndsize(sndwnd, rcvwnd)

DESCRIPTION

Set maximum window size: sndwnd=32, rcvwnd=32 by default

PARAMETERS

sndwnd: send window size
rcvwnd: recive window size

RETURN

None

kcp:lkcp_nodelay(nodelay, interval, resend, nc)

DESCRIPTION

Config re-transmission and flow control

PARAMETERS

nodelay: 0:disable(default), 1:enable
interval: internal update timer interval in millisec, default is 100ms 
resend: 0:disable fast resend(default), 1:enable fast resend
nc: 0:normal congestion control(default), 1:disable congestion control

RETURN

ret: always 0

kcp:lkcp_check(current)

DESCRIPTION

Get when to invoke lkcp_update

PARAMETERS

current: current timestamp in millisec

RETURN

when: timestamp in millisec when to invoke lkcp_update 

kcp:lkcp_update(current)

DESCRIPTION

Update state (call it repeatedly, every 10ms-100ms), or you can ask 

PARAMETERS

current: current timestamp in millisec

RETURN

None

kcp:lkcp_send(data)

DESCRIPTION

User/upper level send

PARAMETERS

data: data to be sent

RETURN

sent_len: below zero for error, otherwise succeed

kcp:lkcp_flush()

DESCRIPTION

Flush pending data

PARAMETERS

None

RETURN

None

kcp:lkcp_input(data)

DESCRIPTION

When you received a low level packet (eg. UDP packet), call it

PARAMETERS

data: data received from transport layer

RETURN

ret: below zero for error, otherwise succeed 

kcp:lkcp_recv()

DESCRIPTION

User/upper level recv 

PARAMETERS

None

RETURN

rcv_len: Less than or equal to 0 for EAGAIN, otherwise for rcv_len 
rcv_buf: if rcv_len greater than 0, rcv_buf is data to recv