python ctypes wctomb and mbtowc

wc.py

import rapi
rapi.start()
# let R to set the locale

import ctypes
from ctypes import wintypes

MultiByteToWideChar = ctypes.windll.kernel32.MultiByteToWideChar
MultiByteToWideChar.argtypes = [wintypes.UINT, wintypes.DWORD,
                                wintypes.LPCSTR, ctypes.c_int,
                                wintypes.LPWSTR, ctypes.c_int]
MultiByteToWideChar.restype = ctypes.c_int

wctomb = ctypes.cdll.msvcrt.wctomb
wctomb.argtypes = [ctypes.POINTER(ctypes.c_char), ctypes.c_wchar]
wctomb.restype = ctypes.c_int

mbtowc = ctypes.cdll.msvcrt.mbtowc
mbtowc.argtypes = [ctypes.POINTER(ctypes.c_wchar), ctypes.POINTER(ctypes.c_char), ctypes.c_size_t]
mbtowc.restype = ctypes.c_int

def utf8tosystem(text):
    s = ctypes.create_string_buffer(10)
    buf = b""
    for c in text:
        n = wctomb(s, c)
        if n > 0:
            buf += s[:n]
    return buf


def system2utf8(buf):
	wcbuf = ctypes.create_unicode_buffer(1)
	text = ""
	while buf: 
		n = mbtowc(wcbuf, buf, len(p))
		if n <= 0:
			break
		text += wcbuf[0]
		buf = buf[n:]
	return text


p = utf8tosystem("甲乙丙")

systemtoutf8(p)