gcc/et-forest.h

   1 /* Et-forest data structure implementation.
   2    Copyright (C) 2002-2023 Free Software Foundation, Inc.
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; see the file COPYING3.  If not see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 /* This package implements ET forest data structure. Each tree in
  19    the structure maintains a tree structure and offers logarithmic time
  20    for tree operations (insertion and removal of nodes and edges) and
  21    poly-logarithmic time for nearest common ancestor.
  22
  23    ET tree stores its structure as a sequence of symbols obtained
  24    by dfs(root)
  25
  26    dfs (node)
  27    {
  28      s = node;
  29      for each child c of node do
  30        s = concat (s, c, node);
  31      return s;
  32    }
  33
  34    For example for tree
  35
  36             1
  37           / | \
  38          2  3  4
  39        / |
  40       4  5
  41
  42    the sequence is 1 2 4 2 5 3 1 3 1 4 1.
  43
  44    The sequence is stored in a slightly modified splay tree.
  45    In order to support various types of node values, a hashtable
  46    is used to convert node values to the internal representation.  */
  47
  48 #ifndef _ET_TREE_H
  49 #define _ET_TREE_H
  50
  51 #ifdef __cplusplus
  52 extern "C" {
  53 #endif /* __cplusplus */
  54
  55 /* The node representing the node in an et tree.  */
  56 struct et_node
  57 {
  58   void *data;                   /* The data represented by the node.  */
  59
  60   int dfs_num_in, dfs_num_out;  /* Number of the node in the dfs ordering.  */
  61
  62   struct et_node *father;       /* Father of the node.  */
  63   struct et_node *son;          /* The first of the sons of the node.  */
  64   struct et_node *left;
  65   struct et_node *right;        /* The brothers of the node.  */
  66
  67   struct et_occ *rightmost_occ; /* The rightmost occurrence.  */
  68   struct et_occ *parent_occ;    /* The occurrence of the parent node.  */
  69 };
  70
  71 struct et_node *et_new_tree (void *data);
  72 void et_free_tree (struct et_node *);
  73 void et_free_tree_force (struct et_node *);
  74 void et_free_pools (void);
  75 void et_set_father (struct et_node *, struct et_node *);
  76 void et_split (struct et_node *);
  77 struct et_node *et_nca (struct et_node *, struct et_node *);
  78 bool et_below (struct et_node *, struct et_node *);
  79 struct et_node *et_root (struct et_node *);
  80
  81 #ifdef __cplusplus
  82 }
  83 #endif /* __cplusplus */
  84
  85 #endif /* _ET_TREE_H */