python可以从C头文件加载定义吗? [英] Can python load definitions from a C header file?

问题描述

我正在围绕C API编写python Wrapper.我有一个详尽的API描述，现在我正在为头文件中定义的枚举的实现而苦苦挣扎.

I'm writing a python Wrapper around a C API. I have an extensive API description and right now I'm struggling with the implementation of enums defined in the header file.

假设我在 myAPI.dll 中具有C API函数，该函数接受枚举作为参数，例如:

Let's assume i have a C API function inside myAPI.dll, that accepts an enum as argument like:

void SomeFunction(SomeEnum data)

从头文件中，我可以看到 SomeEnum 看起来像:

From the header file, I can see that SomeEnum looks like:

enum SomeEnum{
    SomeValue = 1,
    SomeOtherValue = 2,
    SomeVeryStupidValue = -1
};

在python中，我像这样加载 .dll :

In python, I load the .dll like:

myAPI = ctypes.cdll.LoadLibrary('myAPI.dll')

现在我想打电话:

myAPI.SomeFunction(SomeValue)

我知道，我可以在python中定义 SomeValue ，但是直接从头文件中加载其定义或直接将其作为 myAPI .这可能吗?

I know, that I could define SomeValue in python, but it would be convenient to load its definition directly from the header file or have it directly as an attribute of myAPI. Is this possible?

推荐答案

有可能.几年前，我写了一个工具，可以使用 pyparsing enum 语法.一个>.现在是我在此处复制的 pyparsing示例链接更改的情况.如您所见，该文件甚至不必是完全有效的C ++.它定义 enum 语法，并在文件中扫描与语法匹配的文本，从而生成Python变量.

It's possible. I wrote a tool years ago to scan a file for C++ enum syntax using pyparsing. It's now a pyparsing example that I've reproduced here in case the link changes. As you can see the file doesn't have to even be entirely valid C++. It defines the enum grammar and scans the file for text matching the grammar, generating Python variables.

#
# cpp_enum_parser.py
#
# Posted by Mark Tolonen on comp.lang.python in August, 2009,
# Used with permission.
#
# Parser that scans through C or C++ code for enum definitions, and
# generates corresponding Python constant definitions.
#
#

from pyparsing import *

# sample string with enums and other stuff
sample = """
    stuff before
    enum hello {
        Zero,
        One,
        Two,
        Three,
        Five=5,
        Six,
        Ten=10
        };
    in the middle
    enum blah
        {
        alpha,
        beta,
        gamma = 10 ,
        zeta = 50
        };
    at the end
    """

# syntax we don't want to see in the final parse tree
LBRACE, RBRACE, EQ, COMMA = map(Suppress, "{}=,")
_enum = Suppress("enum")
identifier = Word(alphas, alphanums + "_")
integer = Word(nums)
enumValue = Group(identifier("name") + Optional(EQ + integer("value")))
enumList = Group(enumValue + ZeroOrMore(COMMA + enumValue))
enum = _enum + identifier("enum") + LBRACE + enumList("names") + RBRACE

# find instances of enums ignoring other syntax
for item, start, stop in enum.scanString(sample):
    id = 0
    for entry in item.names:
        if entry.value != "":
            id = int(entry.value)
        print("%s_%s = %d" % (item.enum.upper(), entry.name.upper(), id))
        id += 1

输出:

HELLO_ZERO = 0
HELLO_ONE = 1
HELLO_TWO = 2
HELLO_THREE = 3
HELLO_FIVE = 5
HELLO_SIX = 6
HELLO_TEN = 10
BLAH_ALPHA = 0
BLAH_BETA = 1
BLAH_GAMMA = 10
BLAH_ZETA = 50

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