rotations

[K]

I'm working on a splay tree implementation for my Algorithms class.  We were given the following psuedo code for a Left rotation:

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Left-Rotate(T,x)
1   y <-- right[x]   //Set y
2   right[x] <-- left[y]   //Turn y's left subtree into x's right subtree
3   if left[y] != NIL
4     then p[left[y]] <-- x
5   p[y] <-- p[x]   //Link x's parent to y
6   if p[x] = NIL
7      then root[T] <-- y
8   else if x = left[p[x]]
9      then left[p[x]] <-- y
10      else right[p[x]] <-- y
11   left[y] <-- x      // Put x on y's left
12   p[x] <-- y


which I translated as

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void SplayTree::left_rotate(Node* x)
{
   Node* y = x->right;
   x->right = y->left;

   if (y->left)
      y->left->p = x;

   y->p = x->p;

   if (!x->p)
      this->root_ptr = y;
   else if (x == x->p->left)
      x->p->left = y;
   else
      x->p->right = y;

   y->left = x;
   x->p = y;
}


I don't really understand what it's doing, (I do graphically, but not code wise -- Although I really didn't study it.) but I followed the algorithm so my code should be correct.  Can anyone a) try to explain what's going on in order to b) help me implement the right_rotate function.

Thanks.