sbc 1.1

struct convert binary

sbc

介绍

sbc: struct convert binary.C语言格式结构体和二进制转换库.

本软件包已上传到pypi,可输入命令直接安装:

pip install sbc

Python和C对应类型

本软件包封装了ctypes,支持cytpes所有类型,对应表如下:

cyteps type	Ctype	Python type
c_bool	_Bool	bool (1)
c_char	char	1-character bytes object
c_wchar	wchar_t	1-character string
c_byte	char	int
c_ubyte	unsigned char	int
c_short	short	int
c_ushort	unsigned	short int
c_int	int	int
c_uint	unsigned int	int
c_long	long	int
c_ulong	unsigned long	int
c_longlong	__int64 or long long	int
c_ulonglong	unsigned __int64 or unsigned long long	int
c_size_t	size_t	int
c_ssize_t	ssize_t or Py_ssize_t	int
c_float	float	float
c_double	double	float
c_longdouble	long double	float
c_char_p	char * (NUL terminated)	bytes object or None
c_wchar_p	wchar_t * (NUL terminated)	string or None
c_void_p	void *	int or None

使用说明

软件包支持4种C语言结构：

类名	说明
LEFormat	1字节对齐的小端结构体
LEFormatAlign4	4字节对齐的小端结构体
LEFormatAlign8	8字节对齐的小端结构体
BEFormat	1字节对齐的大端结构体
BEFormatAlign4	4字节对齐的大端结构体
BEFormatAlign8	4字节对齐的大端结构体

定义C语言结构体需继承对应的结构体,然后在_fields_中定义对应的成员。示例:

class TStruct1(sbc.LEFormat):
    _fields_ = [
        # (字段名, c类型)
        ('a', sbc.c_uint32),
        ('b', sbc.c_int16),
        ('c', sbc.c_uint8),
    ]____

C结构体转换为二进制字节流使用方法encode,二进制字节流转换为C语言结构体使用方法decode.API:

"""
C语言格式结构体转换成二进制
:return: 返回二进制字节流
"""
def encode(self) -> bytearray

"""
二进制转换成C语言结构体
"""
def decode(self, data: bytearray)

示例

import sbc

import unittest


class TStruct1(sbc.LEFormat):
    _fields_ = [
        # (字段名, c类型)
        ('a', sbc.c_uint32),
        ('b', sbc.c_int16),
        ('c', sbc.c_uint8),
    ]


class TStruct2(sbc.LEFormatAlign4):
    _fields_ = [
        # (字段名, c类型)
        ('a', sbc.c_uint32),
        ('b', sbc.c_int16),
        ('c', sbc.c_uint8),
    ]


class TStruct3(sbc.BEFormat):
    _fields_ = [
        # (字段名, c类型)
        ('a', sbc.c_uint16),
        ('b', sbc.c_uint8 * 5),
        ('c', sbc.c_uint32),
    ]


class _UnitTest(unittest.TestCase):
    def test_case1(self):
        """
        测试小端1字节对齐,C语言结构体转换为二进制
        """
        ts = TStruct1()
        ts.a = 0x12345678
        ts.b = 0x2345
        ts.c = 0x67
        data = ts.encode()
        self.assertEqual(len(data), 7)
        self.assertEqual(data, bytearray([0x78, 0x56, 0x34, 0x12, 0x45, 0x23, 0x67]))

    def test_case2(self):
        """
        测试小端1字节对齐,二进制转换为C语言结构体
        """
        ts = TStruct1()
        ts.decode(bytearray([0x78, 0x56, 0x34, 0x12, 0x45, 0x23, 0x67]))
        self.assertEqual(ts.a, 0x12345678)
        self.assertEqual(ts.b, 0x2345)
        self.assertEqual(ts.c, 0x67)

    def test_case3(self):
        """
        测试小端4字节对齐,C语言结构体转换为二进制
        """
        ts = TStruct2()
        ts.a = 0x12345678
        ts.b = 0x2345
        ts.c = 0x67
        data = ts.encode()
        self.assertEqual(len(data), 8)
        self.assertEqual(data, bytearray([0x78, 0x56, 0x34, 0x12, 0x45, 0x23, 0x67, 0x00]))

    def test_case4(self):
        """
        测试小端4字节对齐,二进制转换为C语言结构体
        """
        ts = TStruct2()
        ts.decode(bytearray([0x78, 0x56, 0x34, 0x12, 0x45, 0x23, 0x67, 0x00]))
        self.assertEqual(ts.a, 0x12345678)
        self.assertEqual(ts.b, 0x2345)
        self.assertEqual(ts.c, 0x67)

    def test_case5(self):
        """
        测试大端1字节对齐,C语言结构体转换为二进制
        """
        ts = TStruct3()
        ts.a = 0x2345
        for i in range(5):
            ts.b[i] = i
        ts.c = 0x12345678
        data = ts.encode()
        self.assertEqual(len(data), 11)
        self.assertEqual(data, bytearray([0x23, 0x45, 0x00, 0x01, 0x02, 0x03, 0x04, 0x12, 0x34, 0x56, 0x78]))


def print_hex(data):
    for i in data:
        print('%x' % i, end=' ')
    print()


if __name__ == '__main__':
    suite = unittest.TestSuite()
    runner = unittest.TextTestRunner()
    runner.run(suite)