C中指针点的深层副本

Question

我需要你的帮助!

我喜欢复制这样的结构:

typedef struct PackageObject_s {
  long  **vertex;          // vertices
  long    num_vertex;      // count of vertices
  long    objectType;      // 
  REAL    r;               // 
  long    bottom[3];       // bounding box bottom vector
  long    top[3];          // bounding box top vector
  long   *start;           // 
  REAL    coverage;        // 
} PackageObject __attribute__ ((aligned));

我试试这样:

static inline void PackageObject_copy(PackageObject *dst, const PackageObject *src) {

  dst->num_vertex = src->num_vertex;
  dst->objectType = src->objectType;
  dst->r          = src->r;
  vec_assign3l(dst->bottom, src->bottom);
  vec_assign3l(dst->top,    src->top);

  // TODO copy **vertex ???

  dst->coverage   = src->coverage;
  dst->coverage   = src->coverage;
}

我怎么解决这个问题？

预先感谢您的帮助!!

更新 - 我的深度复制解决方案vertex- thx所有帮助:

dst->vertex = (long *)malloc(dst->num_vertex * 3 * sizeof(long));
for (long i=0; i < src->num_vertex; i++) { 
  dst->vertex[i] = (long)malloc(3*sizeof(long)); 
  memcpy(dst->vertex[i],src->vertex[i],3 * sizeof(long)); 
}

Answer 1

我假设对象之间不共享顶点。也就是说，它们属于所讨论的结构。

有两种主要情况需要考虑：

1. Copying into a new object
2. Copying into an existing object

复制到新对象中非常简单。

1a. Allocate space for <num_vertex> pointers.
1b. Allocate space for each vertex.
2a. Copy <num_vertex> pointers from source to destination.
2b. Copy <num_vertex> vertices from source to destination.

复制到现有对象与复制到新对象非常相似，只是您必须先执行以下操作。

0a. Loop through each element of <vertex> and free the vertex.
0b. Free the array of vertex pointers.
1. Follow the steps for copying into a new object.

希望这可以帮助。