ctags/main/rbtree.h

   1 /*
   2   Red Black Trees
   3   (C) 1999  Andrea Arcangeli <andrea@suse.de>
   4
   5   This program is free software; you can redistribute it and/or modify
   6   it under the terms of the GNU General Public License as published by
   7   the Free Software Foundation; either version 2 of the License, or
   8   (at your option) any later version.
   9
  10   This program is distributed in the hope that it will be useful,
  11   but WITHOUT ANY WARRANTY; without even the implied warranty of
  12   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13   GNU General Public License for more details.
  14
  15   You should have received a copy of the GNU General Public License
  16   along with this program; if not, write to the Free Software
  17   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18
  19   linux/include/linux/rbtree.h
  20
  21   To use rbtrees you'll have to implement your own insert and search cores.
  22   This will avoid us to use callbacks and to drop drammatically performances.
  23   I know it's not the cleaner way,  but in C (not in C++) to get
  24   performances and genericity...
  25
  26   See Documentation/rbtree.txt for documentation and samples.
  27 */
  28
  29 #ifndef CTAGS_MAIN_RBTREE_H
  30 #define CTAGS_MAIN_RBTREE_H
  31
  32 #include "general.h"
  33 #include <stddef.h>
  34 #include <stdint.h>
  35
  36 #include "inline.h"
  37 #include "gcc-attr.h"
  38
  39 #if defined(container_of)
  40   #undef container_of
  41 #if defined(HAVE_TYPEOF) && defined(HAVE_STATEMENT_EXPRESSION_EXT)
  42   #define container_of(ptr, type, member) ({                    \
  43                 const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
  44                 (type *)( (char *)__mptr - offsetof(type,member) );})
  45 #else
  46   #define container_of(ptr, type, member) \
  47                 ((type *)( (char *)ptr - offsetof(type,member)))
  48 #endif  /* defined(HAVE_TYPEOF) && defined(HAVE_STATEMENT_EXPRESSION_EXT) */
  49 #else
  50 #if defined(HAVE_TYPEOF) && defined(HAVE_STATEMENT_EXPRESSION_EXT)
  51   #define container_of(ptr, type, member) ({                    \
  52                 const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
  53                 (type *)( (char *)__mptr - offsetof(type,member) );})
  54 #else
  55   #define container_of(ptr, type, member) \
  56                 ((type *)( (char *)ptr - offsetof(type,member)))
  57 #endif /* defined(HAVE_TYPEOF) && defined(HAVE_STATEMENT_EXPRESSION_EXT) */
  58 #endif /* defined(container_of) */
  59
  60 struct rb_node {
  61         uintptr_t  __rb_parent_color;
  62         struct rb_node *rb_right;
  63         struct rb_node *rb_left;
  64 } CTAGA_ATTR_ALIGNED(sizeof(long));
  65         /* The alignment might seem pointless, but allegedly CRIS needs it */
  66
  67 struct rb_root {
  68         struct rb_node *rb_node;
  69 };
  70
  71
  72 #define rb_parent(r)   ((struct rb_node *)((r)->__rb_parent_color & ~3))
  73
  74 #define RB_ROOT (struct rb_root) { NULL, }
  75 #define rb_entry(ptr, type, member) container_of(ptr, type, member)
  76
  77 #define RB_EMPTY_ROOT(root)  ((root)->rb_node == NULL)
  78
  79 /* 'empty' nodes are nodes that are known not to be inserted in an rbtree */
  80 #define RB_EMPTY_NODE(node)  \
  81         ((node)->__rb_parent_color == (uintptr_t)(node))
  82 #define RB_CLEAR_NODE(node)  \
  83         ((node)->__rb_parent_color = (uintptr_t)(node))
  84
  85
  86 extern void rb_insert_color(struct rb_node *, struct rb_root *);
  87 extern void rb_erase(struct rb_node *, struct rb_root *);
  88
  89
  90 /* Find logical next and previous nodes in a tree */
  91 extern struct rb_node *rb_next(const struct rb_node *);
  92 extern struct rb_node *rb_prev(const struct rb_node *);
  93 extern struct rb_node *rb_first(const struct rb_root *);
  94 extern struct rb_node *rb_last(const struct rb_root *);
  95
  96 /* Postorder iteration - always visit the parent after its children */
  97 extern struct rb_node *rb_first_postorder(const struct rb_root *);
  98 extern struct rb_node *rb_next_postorder(const struct rb_node *);
  99
 100 /* Fast replacement of a single node without remove/rebalance/add/rebalance */
 101 extern void rb_replace_node(struct rb_node *victim, struct rb_node *new,
 102                                 struct rb_root *root);
 103
 104 CTAGS_INLINE void rb_link_node(struct rb_node * node, struct rb_node * parent,
 105                                 struct rb_node ** rb_link)
 106 {
 107         node->__rb_parent_color = (uintptr_t)parent;
 108         node->rb_left = node->rb_right = NULL;
 109
 110         *rb_link = node;
 111 }
 112
 113 #define rb_entry_safe(ptr, type, member) \
 114         ({ typeof(ptr) ____ptr = (ptr); \
 115            ____ptr ? rb_entry(____ptr, type, member) : NULL; \
 116         })
 117
 118 /**
 119  * rbtree_postorder_for_each_entry_safe - iterate over rb_root in post order of
 120  * given type safe against removal of rb_node entry
 121  *
 122  * @pos:        the 'type *' to use as a loop cursor.
 123  * @n:          another 'type *' to use as temporary storage
 124  * @root:       'rb_root *' of the rbtree.
 125  * @field:      the name of the rb_node field within 'type'.
 126  */
 127 #define rbtree_postorder_for_each_entry_safe(pos, n, root, field) \
 128         for (pos = rb_entry_safe(rb_first_postorder(root), typeof(*pos), field); \
 129                  pos && ({ n = rb_entry_safe(rb_next_postorder(&pos->field), \
 130                         typeof(*pos), field); 1; }); \
 131                  pos = n)
 132
 133 #endif  /* CTAGS_MAIN_RBTREE_H */