如何使用cython包装参数为wchar_t指针的C函数

时间:2012-10-08 09:27:07

标签: pointers cython

我想使用cython来包装C库。库中的一个功能就像

int hid_get_manufacturer_string(hid_device *device, wchar_t *string, size_t maxlen);

有两个问题:

  1. 我可以使用cython中的wchar_t做什么;

  2. 如何转换.pyx文件中的字符串指针。

1 个答案:

答案 0 :(得分:1)

声明wchar_t:

cdef extern from "stddef.h":
    ctypedef void wchar_t

或从libc模块导入:

from libc.stddef cimport wchar_t

使用WideCharToMultiByte将wchar_t转换为python字符串的函数(参见CefStringToPyString):

# Declare these in .pxd file:
#
# cdef extern from "Windows.h":
#     cdef int CP_UTF8
#     cdef int WideCharToMultiByte(int, int, wchar_t*, int, char*, int, char*, int*)

cdef object WideCharToPyString(wchar_t *wcharstr):
    cdef int charstr_bytes = WideCharToMultiByte(CP_UTF8, 0, wcharstr, -1, NULL, 0, NULL, NULL)
    # Do not use malloc, otherwise you get trash data when string is empty.
    cdef char* charstr = <char*>calloc(charstr_bytes, sizeof(char))
    cdef int copied_bytes = WideCharToMultiByte(CP_UTF8, 0, wcharstr, -1, charstr, charstr_bytes, NULL, NULL)
    if bytes == str:
        pystring = "" + charstr # Python 2.7
    else:
        pystring = (b"" + charstr).decode("utf-8", "ignore") # Python 3
    free(charstr)
    return pystring

从Python 3.2开始,您可以使用PyUnicode_FromWideChar(wcharstr,-1)来执行此操作,请参阅compostus的注释。