rbtree.h

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/*
 * =============================================================================
 *
 *       Filename:  rbtree.h
 *
 *    Description:  rbtree(Red-Black tree) implementation adapted from linux
 *                  kernel thus can be used in userspace c program.
 *
 *        Created:  09/02/2012 11:36:11 PM
 *
 *         Author:  Fu Haiping (forhappy), haipingf@gmail.com
 *        Company:  ICT ( Institute Of Computing Technology, CAS )
 *
 * =============================================================================
 */
 
/*
  Red Black Trees
  (C) 1999  Andrea Arcangeli <andrea@suse.de>
 
  This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation; either version 2 of the License, or
  (at your option) any later version.
 
  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.
 
  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 
  linux/include/linux/rbtree.h
 
  To use rbtrees you'll have to implement your own insert and search cores.
  This will avoid us to use callbacks and to drop drammatically performances.
  I know it's not the cleaner way,  but in C (not in C++) to get
  performances and genericity...
 
  Some example of insert and search follows here. The search is a plain
  normal search over an ordered tree. The insert instead must be implemented
  in two steps: First, the code must insert the element in order as a red leaf
  in the tree, and then the support library function rb_insert_color() must
  be called. Such function will do the not trivial work to rebalance the
  rbtree, if necessary.
 
-----------------------------------------------------------------------
static inline struct page * rb_search_page_cache(struct inode * inode,
                         unsigned long offset)
{
    struct rb_node * n = inode->i_rb_page_cache.rb_node;
    struct page * page;
 
    while (n)
    {
        page = rb_entry(n, struct page, rb_page_cache);
 
        if (offset < page->offset)
            n = n->rb_left;
        else if (offset > page->offset)
            n = n->rb_right;
        else
            return page;
    }
    return NULL;
}
 
static inline struct page * __rb_insert_page_cache(struct inode * inode,
                           unsigned long offset,
                           struct rb_node * node)
{
    struct rb_node ** p = &inode->i_rb_page_cache.rb_node;
    struct rb_node * parent = NULL;
    struct page * page;
 
    while (*p)
    {
        parent = *p;
        page = rb_entry(parent, struct page, rb_page_cache);
 
        if (offset < page->offset)
            p = &(*p)->rb_left;
        else if (offset > page->offset)
            p = &(*p)->rb_right;
        else
            return page;
    }
 
    rb_link_node(node, parent, p);
 
    return NULL;
}
 
static inline struct page * rb_insert_page_cache(struct inode * inode,
                         unsigned long offset,
                         struct rb_node * node)
{
    struct page * ret;
    if ((ret = __rb_insert_page_cache(inode, offset, node)))
        goto out;
    rb_insert_color(node, &inode->i_rb_page_cache);
 out:
    return ret;
}
-----------------------------------------------------------------------
*/
 
#ifndef CTAGS_MAIN_RBTREE_H
#define CTAGS_MAIN_RBTREE_H
 
#include "general.h"
#include "inline.h"
#include "gcc-attr.h"
#include <stdint.h>
 
#if defined(container_of)
  #undef container_of
#if defined(HAVE_TYPEOF) && defined(HAVE_STATEMENT_EXPRESSION_EXT)
  #define container_of(ptr, type, member) ({            \
        const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
        (type *)( (char *)__mptr - offsetof(type,member) );})
#else
  #define container_of(ptr, type, member) \
        ((type *)( (char *)ptr - offsetof(type,member)))
#endif  /* defined(HAVE_TYPEOF) && defined(HAVE_STATEMENT_EXPRESSION_EXT) */
#else
#if defined(HAVE_TYPEOF) && defined(HAVE_STATEMENT_EXPRESSION_EXT)
  #define container_of(ptr, type, member) ({            \
        const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
        (type *)( (char *)__mptr - offsetof(type,member) );})
#else
  #define container_of(ptr, type, member) \
        ((type *)( (char *)ptr - offsetof(type,member)))
#endif /* defined(HAVE_TYPEOF) && defined(HAVE_STATEMENT_EXPRESSION_EXT) */
#endif /* defined(container_of) */
 
#if defined(offsetof)
  #undef offsetof
  #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
#else
  #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
#endif
 
#undef NULL
#if defined(__cplusplus)
  #define NULL 0
#else
  #define NULL ((void *)0)
#endif
 
struct rb_node
{
    uintptr_t  rb_parent_color;
#define RB_RED      0
#define RB_BLACK    1
    struct rb_node *rb_right;
    struct rb_node *rb_left;
} CTAGA_ATTR_ALIGNED(sizeof(long));
    /* The alignment might seem pointless, but allegedly CRIS needs it */
 
struct rb_root
{
    struct rb_node *rb_node;
};
 
 
#define rb_parent(r)   ((struct rb_node *)((r)->rb_parent_color & ~3))
#define rb_color(r)   ((r)->rb_parent_color & 1)
#define rb_is_red(r)   (!rb_color(r))
#define rb_is_black(r) rb_color(r)
#define rb_set_red(r)  do { (r)->rb_parent_color &= ~1; } while (0)
#define rb_set_black(r)  do { (r)->rb_parent_color |= 1; } while (0)
 
CTAGS_INLINE void rb_set_parent(struct rb_node *rb, struct rb_node *p)
{
    rb->rb_parent_color = (rb->rb_parent_color & 3) | (uintptr_t)p;
}
CTAGS_INLINE void rb_set_color(struct rb_node *rb, int color)
{
    rb->rb_parent_color = (rb->rb_parent_color & ~1) | color;
}
 
#define RB_ROOT (struct rb_root) { NULL, }
#define rb_entry(ptr, type, member) container_of(ptr, type, member)
 
#define RB_EMPTY_ROOT(root) ((root)->rb_node == NULL)
#define RB_EMPTY_NODE(node) (rb_parent(node) == node)
#define RB_CLEAR_NODE(node) (rb_set_parent(node, node))
 
CTAGS_INLINE void rb_init_node(struct rb_node *rb)
{
    rb->rb_parent_color = 0;
    rb->rb_right = NULL;
    rb->rb_left = NULL;
    RB_CLEAR_NODE(rb);
}
 
extern void rb_insert_color(struct rb_node *, struct rb_root *);
extern void rb_erase(struct rb_node *, struct rb_root *);
 
typedef void (*rb_augment_f)(struct rb_node *node, void *data);
 
extern void rb_augment_insert(struct rb_node *node,
                  rb_augment_f func, void *data);
extern struct rb_node *rb_augment_erase_begin(struct rb_node *node);
extern void rb_augment_erase_end(struct rb_node *node,
                 rb_augment_f func, void *data);
 
/* Find logical next and previous nodes in a tree */
extern struct rb_node *rb_next(const struct rb_node *);
extern struct rb_node *rb_prev(const struct rb_node *);
extern struct rb_node *rb_first(const struct rb_root *);
extern struct rb_node *rb_last(const struct rb_root *);
 
/* Fast replacement of a single node without remove/rebalance/add/rebalance */
extern void rb_replace_node(struct rb_node *victim, struct rb_node *new,
                struct rb_root *root);
 
CTAGS_INLINE void rb_link_node(struct rb_node * node, struct rb_node * parent,
                struct rb_node ** rb_link)
{
    node->rb_parent_color = (uintptr_t)parent;
    node->rb_left = node->rb_right = NULL;
 
    *rb_link = node;
}
 
#endif  /* CTAGS_MAIN_RBTREE_H */