LXR uboot/include/linux/rbtree.h

   1/* SPDX-License-Identifier: GPL-2.0+ */
   2/*
   3  Red Black Trees
   4  (C) 1999  Andrea Arcangeli <andrea@suse.de>
   5  
   6  linux/include/linux/rbtree.h
   7
   8  To use rbtrees you'll have to implement your own insert and search cores.
   9  This will avoid us to use callbacks and to drop drammatically performances.
  10  I know it's not the cleaner way,  but in C (not in C++) to get
  11  performances and genericity...
  12
  13  See Documentation/rbtree.txt for documentation and samples.
  14*/
  15
  16#ifndef _LINUX_RBTREE_H
  17#define _LINUX_RBTREE_H
  18
  19#ifndef __UBOOT__
  20#include <linux/kernel.h>
  21#endif
  22#include <linux/stddef.h>
  23
  24struct rb_node {
  25        unsigned long  __rb_parent_color;
  26        struct rb_node *rb_right;
  27        struct rb_node *rb_left;
  28} __attribute__((aligned(sizeof(long))));
  29    /* The alignment might seem pointless, but allegedly CRIS needs it */
  30
  31struct rb_root {
  32        struct rb_node *rb_node;
  33};
  34
  35
  36#define rb_parent(r)   ((struct rb_node *)((r)->__rb_parent_color & ~3))
  37
  38#define RB_ROOT (struct rb_root) { NULL, }
  39#define rb_entry(ptr, type, member) container_of(ptr, type, member)
  40
  41#define RB_EMPTY_ROOT(root)  ((root)->rb_node == NULL)
  42
  43/* 'empty' nodes are nodes that are known not to be inserted in an rbree */
  44#define RB_EMPTY_NODE(node)  \
  45        ((node)->__rb_parent_color == (unsigned long)(node))
  46#define RB_CLEAR_NODE(node)  \
  47        ((node)->__rb_parent_color = (unsigned long)(node))
  48
  49
  50extern void rb_insert_color(struct rb_node *, struct rb_root *);
  51extern void rb_erase(struct rb_node *, struct rb_root *);
  52
  53
  54/* Find logical next and previous nodes in a tree */
  55extern struct rb_node *rb_next(const struct rb_node *);
  56extern struct rb_node *rb_prev(const struct rb_node *);
  57extern struct rb_node *rb_first(const struct rb_root *);
  58extern struct rb_node *rb_last(const struct rb_root *);
  59
  60/* Postorder iteration - always visit the parent after its children */
  61extern struct rb_node *rb_first_postorder(const struct rb_root *);
  62extern struct rb_node *rb_next_postorder(const struct rb_node *);
  63
  64/* Fast replacement of a single node without remove/rebalance/add/rebalance */
  65extern void rb_replace_node(struct rb_node *victim, struct rb_node *new, 
  66                            struct rb_root *root);
  67
  68static inline void rb_link_node(struct rb_node * node, struct rb_node * parent,
  69                                struct rb_node ** rb_link)
  70{
  71        node->__rb_parent_color = (unsigned long)parent;
  72        node->rb_left = node->rb_right = NULL;
  73
  74        *rb_link = node;
  75}
  76
  77#define rb_entry_safe(ptr, type, member) \
  78        ({ typeof(ptr) ____ptr = (ptr); \
  79           ____ptr ? rb_entry(____ptr, type, member) : NULL; \
  80        })
  81
  82/**
  83 * rbtree_postorder_for_each_entry_safe - iterate over rb_root in post order of
  84 * given type safe against removal of rb_node entry
  85 *
  86 * @pos:        the 'type *' to use as a loop cursor.
  87 * @n:          another 'type *' to use as temporary storage
  88 * @root:       'rb_root *' of the rbtree.
  89 * @field:      the name of the rb_node field within 'type'.
  90 */
  91#define rbtree_postorder_for_each_entry_safe(pos, n, root, field) \
  92        for (pos = rb_entry_safe(rb_first_postorder(root), typeof(*pos), field); \
  93             pos && ({ n = rb_entry_safe(rb_next_postorder(&pos->field), \
  94                        typeof(*pos), field); 1; }); \
  95             pos = n)
  96
  97#endif  /* _LINUX_RBTREE_H */
  98