如何将字符串的Python列表转换为wchar_t的C数组？ [英] How to convert Python list of strings into C array of wchar_t?

问题描述

C语言的源代码如下：

The source code in C looks like:

typedef wchar_t            char_t;
typedef const char_t*  const_string_t;
static const_string_t g_symbols[] = { {L"IBM"}, {L"MSFT"}, {L"YHOO"}, {L"C"} };
...
some_c_func(g_symbols)
...

some_c_func声明为较早的某个地方，例如：

some_c_func is declared somewhere earlier with something like:

int some_c_func(const_string_t* symbols)

将g_symbols传递给some_c_func函数很重要，因此我必须为其编写包装器，应该看起来

It is important that g_symbols is passed to some_c_func function, so I have to write wrapper over it, that should look somehow like:

ctypedef wchar_t char_t
ctypedef const char_t*  const_string_t

def some_py_func(py_list=['a', 'b', 'c']):
    g_symbols = ... # some transformation from py_list to g_symbols
    some_c_func(g_symbols)
    print('Done!')

我将不胜感激

推荐答案

感谢@DavidW，但是我发现解决方案更简单：

Thanks to @DavidW, but I found, I think, simplier solution:

from cpython.mem cimport PyMem_Malloc, PyMem_Free

def some_py_func(py_list=['a', 'b', 'c']):
    cdef int number = len(symbols)  # get c int of elements
    cdef int idx # for faster loops

    # create array with dynamic memory allocation
    cdef const_string_t *g_symbols = <const_string_t *> PyMem_Malloc(number * sizeof(const_string_t))

    # create array with cycle
    for idx, sym in enumerate(py_list):
        g_symbols[idx] = PyUnicode_AsWideCharString(sym, NULL)

    # call c function
    some_c_func(g_symbols)

    # free memory
    for idx in range(number):
        PyMem_Free(g_symbols[idx])
    PyMem_Free(g_symbols)
    print('Done!')

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