Python ctypes结构体深度复制技巧：解决指针字段问题

import ctypes as ct

class Group(ct.Structure):
    _fields_ = (('ChSize', ct.c_uint32 * 9),          # 存储每个数据通道的尺寸
                ('DataChannel', ct.POINTER(ct.c_float) * 9), # 9个指向浮点数数组的指针
                ('TriggerTimeLag', ct.c_uint32),
                ('StartIndexCell', ct.c_uint16))

    def __repr__(self):
        """
        为Group对象提供一个可读的字符串表示，便于调试和验证。
        """
        s = f'Group(ChSize={self.ChSize[:]}, TriggerTimeLag={self.TriggerTimeLag}, StartIndexCell={self.StartIndexCell})\n'
        for i in range(9):
            # 尝试访问DataChannel指向的数据，如果指针有效且ChSize指示长度大于0
            try:
                if self.DataChannel[i] and self.ChSize[i] > 0:
                    s += f'  DataChannel[{i}] = {self.DataChannel[i][:self.ChSize[i]]}\n'
                else:
                    s += f'  DataChannel[{i}] = []\n'
            except Exception:
                s += f'  DataChannel[{i}] = <invalid pointer or size>\n'
        return s

    def deepcopy(self):
        """
        实现Group结构体的深度复制。
        """
        # 步骤一：创建结构体本身的浅层副本
        # from_buffer_copy会复制所有固定大小的字段，包括指针值。
        copy = Group.from_buffer_copy(self)

        # 步骤二：深度复制指针指向的外部数据
        for i, (size, channel_ptr) in enumerate(zip(self.ChSize, self.DataChannel)):
            if size > 0 and channel_ptr: # 确保通道有数据且指针有效
                # 创建一个新的ctypes数组来存储数据副本
                # (*channel_ptr[:size]) 将原始指针指向的数据解引用并作为列表传递给新数组
                new_data_array = (ct.c_float * size)(*channel_ptr[:size])
                # 将新数组的地址转换为POINTER(ct.c_float)类型，并赋值给副本的DataChannel字段
                copy.DataChannel[i] = ct.cast(new_data_array, ct.POINTER(ct.c_float))
            else:
                # 如果原始通道无数据或指针无效，则副本对应通道也为空
                copy.DataChannel[i] = None 
        return copy

# --- 验证深度复制功能 ---

# 1. 创建、初始化并显示一个原始Group对象
group = Group()
group.ChSize[:] = [1, 2, 3, 4, 5, 6, 7, 8, 9] # 设置每个通道的数据长度
for i, size in enumerate(group.ChSize):
    # 为每个DataChannel分配并初始化独立的浮点数数组
    data = (ct.c_float * size)(*[1.5 * n for n in range(size)])
    group.DataChannel[i] = ct.cast(data, ct.POINTER(ct.c_float))
group.TriggerTimeLag = 123
group.StartIndexCell = 456
print("--- 原始 Group 对象 ---")
print(group)

# 2. 创建原始Group对象的深度副本
copy = group.deepcopy()

# 3. 修改原始Group对象的数据，以验证副本的独立性
print("\n--- 修改原始 Group 对象的数据 ---")
group.ChSize[:] = [0] * 9 # 将所有通道的尺寸设为0
group.DataChannel[:] = [None] * 9 # 将所有DataChannel指针设为None
group.TriggerTimeLag = 999
group.StartIndexCell = 888

print("\n--- 修改后的原始 Group 对象 ---")
print(group)

print("\n--- 深度复制后的 Group 对象 (应保持不变) ---")
print(copy)

--- 原始 Group 对象 ---
Group(ChSize=[1, 2, 3, 4, 5, 6, 7, 8, 9], TriggerTimeLag=123, StartIndexCell=456)
  DataChannel[0] = [0.0]
  DataChannel[1] = [0.0, 1.5]
  DataChannel[2] = [0.0, 1.5, 3.0]
  DataChannel[3] = [0.0, 1.5, 3.0, 4.5]
  DataChannel[4] = [0.0, 1.5, 3.0, 4.5, 6.0]
  DataChannel[5] = [0.0, 1.5, 3.0, 4.5, 6.0, 7.5]
  DataChannel[6] = [0.0, 1.5, 3.0, 4.5, 6.0, 7.5, 9.0]
  DataChannel[7] = [0.0, 1.5, 3.0, 4.5, 6.0, 7.5, 9.0, 10.5]
  DataChannel[8] = [0.0, 1.5, 3.0, 4.5, 6.0, 7.5, 9.0, 10.5, 12.0]

--- 修改原始 Group 对象的数据 ---

--- 修改后的原始 Group 对象 ---
Group(ChSize=[0, 0, 0, 0, 0, 0, 0, 0, 0], TriggerTimeLag=999, StartIndexCell=888)
  DataChannel[0] = []
  DataChannel[1] = []
  DataChannel[2] = []
  DataChannel[3] = []
  DataChannel[4] = []
  DataChannel[5] = []
  DataChannel[6] = []
  DataChannel[7] = []
  DataChannel[8] = []

--- 深度复制后的 Group 对象 (应保持不变) ---
Group(ChSize=[1, 2, 3, 4, 5, 6, 7, 8, 9], TriggerTimeLag=123, StartIndexCell=456)
  DataChannel[0] = [0.0]
  DataChannel[1] = [0.0, 1.5]
  DataChannel[2] = [0.0, 1.5, 3.0]
  DataChannel[3] = [0.0, 1.5, 3.0, 4.5]
  DataChannel[4] = [0.0, 1.5, 3.0, 4.5, 6.0]
  DataChannel[5] = [0.0, 1.5, 3.0, 4.5, 6.0, 7.5]
  DataChannel[6] = [0.0, 1.5, 3.0, 4.5, 6.0, 7.5, 9.0]
  DataChannel[7] = [0.0, 1.5, 3.0, 4.5, 6.0, 7.5, 9.0, 10.5]
  DataChannel[8] = [0.0, 1.5, 3.0, 4.5, 6.0, 7.5, 9.0, 10.5, 12.0]