mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-06 02:50:43 +00:00
192 lines
7 KiB
C
192 lines
7 KiB
C
![]() |
/*
|
||
|
Interval Trees
|
||
|
(C) 2012 Michel Lespinasse <walken@google.com>
|
||
|
|
||
|
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
|
||
|
|
||
|
include/linux/interval_tree_generic.h
|
||
|
*/
|
||
|
|
||
|
#include <linux/rbtree_augmented.h>
|
||
|
|
||
|
/*
|
||
|
* Template for implementing interval trees
|
||
|
*
|
||
|
* ITSTRUCT: struct type of the interval tree nodes
|
||
|
* ITRB: name of struct rb_node field within ITSTRUCT
|
||
|
* ITTYPE: type of the interval endpoints
|
||
|
* ITSUBTREE: name of ITTYPE field within ITSTRUCT holding last-in-subtree
|
||
|
* ITSTART(n): start endpoint of ITSTRUCT node n
|
||
|
* ITLAST(n): last endpoint of ITSTRUCT node n
|
||
|
* ITSTATIC: 'static' or empty
|
||
|
* ITPREFIX: prefix to use for the inline tree definitions
|
||
|
*
|
||
|
* Note - before using this, please consider if non-generic version
|
||
|
* (interval_tree.h) would work for you...
|
||
|
*/
|
||
|
|
||
|
#define INTERVAL_TREE_DEFINE(ITSTRUCT, ITRB, ITTYPE, ITSUBTREE, \
|
||
|
ITSTART, ITLAST, ITSTATIC, ITPREFIX) \
|
||
|
\
|
||
|
/* Callbacks for augmented rbtree insert and remove */ \
|
||
|
\
|
||
|
static inline ITTYPE ITPREFIX ## _compute_subtree_last(ITSTRUCT *node) \
|
||
|
{ \
|
||
|
ITTYPE max = ITLAST(node), subtree_last; \
|
||
|
if (node->ITRB.rb_left) { \
|
||
|
subtree_last = rb_entry(node->ITRB.rb_left, \
|
||
|
ITSTRUCT, ITRB)->ITSUBTREE; \
|
||
|
if (max < subtree_last) \
|
||
|
max = subtree_last; \
|
||
|
} \
|
||
|
if (node->ITRB.rb_right) { \
|
||
|
subtree_last = rb_entry(node->ITRB.rb_right, \
|
||
|
ITSTRUCT, ITRB)->ITSUBTREE; \
|
||
|
if (max < subtree_last) \
|
||
|
max = subtree_last; \
|
||
|
} \
|
||
|
return max; \
|
||
|
} \
|
||
|
\
|
||
|
RB_DECLARE_CALLBACKS(static, ITPREFIX ## _augment, ITSTRUCT, ITRB, \
|
||
|
ITTYPE, ITSUBTREE, ITPREFIX ## _compute_subtree_last) \
|
||
|
\
|
||
|
/* Insert / remove interval nodes from the tree */ \
|
||
|
\
|
||
|
ITSTATIC void ITPREFIX ## _insert(ITSTRUCT *node, struct rb_root *root) \
|
||
|
{ \
|
||
|
struct rb_node **link = &root->rb_node, *rb_parent = NULL; \
|
||
|
ITTYPE start = ITSTART(node), last = ITLAST(node); \
|
||
|
ITSTRUCT *parent; \
|
||
|
\
|
||
|
while (*link) { \
|
||
|
rb_parent = *link; \
|
||
|
parent = rb_entry(rb_parent, ITSTRUCT, ITRB); \
|
||
|
if (parent->ITSUBTREE < last) \
|
||
|
parent->ITSUBTREE = last; \
|
||
|
if (start < ITSTART(parent)) \
|
||
|
link = &parent->ITRB.rb_left; \
|
||
|
else \
|
||
|
link = &parent->ITRB.rb_right; \
|
||
|
} \
|
||
|
\
|
||
|
node->ITSUBTREE = last; \
|
||
|
rb_link_node(&node->ITRB, rb_parent, link); \
|
||
|
rb_insert_augmented(&node->ITRB, root, &ITPREFIX ## _augment); \
|
||
|
} \
|
||
|
\
|
||
|
ITSTATIC void ITPREFIX ## _remove(ITSTRUCT *node, struct rb_root *root) \
|
||
|
{ \
|
||
|
rb_erase_augmented(&node->ITRB, root, &ITPREFIX ## _augment); \
|
||
|
} \
|
||
|
\
|
||
|
/* \
|
||
|
* Iterate over intervals intersecting [start;last] \
|
||
|
* \
|
||
|
* Note that a node's interval intersects [start;last] iff: \
|
||
|
* Cond1: ITSTART(node) <= last \
|
||
|
* and \
|
||
|
* Cond2: start <= ITLAST(node) \
|
||
|
*/ \
|
||
|
\
|
||
|
static ITSTRUCT * \
|
||
|
ITPREFIX ## _subtree_search(ITSTRUCT *node, ITTYPE start, ITTYPE last) \
|
||
|
{ \
|
||
|
while (true) { \
|
||
|
/* \
|
||
|
* Loop invariant: start <= node->ITSUBTREE \
|
||
|
* (Cond2 is satisfied by one of the subtree nodes) \
|
||
|
*/ \
|
||
|
if (node->ITRB.rb_left) { \
|
||
|
ITSTRUCT *left = rb_entry(node->ITRB.rb_left, \
|
||
|
ITSTRUCT, ITRB); \
|
||
|
if (start <= left->ITSUBTREE) { \
|
||
|
/* \
|
||
|
* Some nodes in left subtree satisfy Cond2. \
|
||
|
* Iterate to find the leftmost such node N. \
|
||
|
* If it also satisfies Cond1, that's the \
|
||
|
* match we are looking for. Otherwise, there \
|
||
|
* is no matching interval as nodes to the \
|
||
|
* right of N can't satisfy Cond1 either. \
|
||
|
*/ \
|
||
|
node = left; \
|
||
|
continue; \
|
||
|
} \
|
||
|
} \
|
||
|
if (ITSTART(node) <= last) { /* Cond1 */ \
|
||
|
if (start <= ITLAST(node)) /* Cond2 */ \
|
||
|
return node; /* node is leftmost match */ \
|
||
|
if (node->ITRB.rb_right) { \
|
||
|
node = rb_entry(node->ITRB.rb_right, \
|
||
|
ITSTRUCT, ITRB); \
|
||
|
if (start <= node->ITSUBTREE) \
|
||
|
continue; \
|
||
|
} \
|
||
|
} \
|
||
|
return NULL; /* No match */ \
|
||
|
} \
|
||
|
} \
|
||
|
\
|
||
|
ITSTATIC ITSTRUCT * \
|
||
|
ITPREFIX ## _iter_first(struct rb_root *root, ITTYPE start, ITTYPE last) \
|
||
|
{ \
|
||
|
ITSTRUCT *node; \
|
||
|
\
|
||
|
if (!root->rb_node) \
|
||
|
return NULL; \
|
||
|
node = rb_entry(root->rb_node, ITSTRUCT, ITRB); \
|
||
|
if (node->ITSUBTREE < start) \
|
||
|
return NULL; \
|
||
|
return ITPREFIX ## _subtree_search(node, start, last); \
|
||
|
} \
|
||
|
\
|
||
|
ITSTATIC ITSTRUCT * \
|
||
|
ITPREFIX ## _iter_next(ITSTRUCT *node, ITTYPE start, ITTYPE last) \
|
||
|
{ \
|
||
|
struct rb_node *rb = node->ITRB.rb_right, *prev; \
|
||
|
\
|
||
|
while (true) { \
|
||
|
/* \
|
||
|
* Loop invariants: \
|
||
|
* Cond1: ITSTART(node) <= last \
|
||
|
* rb == node->ITRB.rb_right \
|
||
|
* \
|
||
|
* First, search right subtree if suitable \
|
||
|
*/ \
|
||
|
if (rb) { \
|
||
|
ITSTRUCT *right = rb_entry(rb, ITSTRUCT, ITRB); \
|
||
|
if (start <= right->ITSUBTREE) \
|
||
|
return ITPREFIX ## _subtree_search(right, \
|
||
|
start, last); \
|
||
|
} \
|
||
|
\
|
||
|
/* Move up the tree until we come from a node's left child */ \
|
||
|
do { \
|
||
|
rb = rb_parent(&node->ITRB); \
|
||
|
if (!rb) \
|
||
|
return NULL; \
|
||
|
prev = &node->ITRB; \
|
||
|
node = rb_entry(rb, ITSTRUCT, ITRB); \
|
||
|
rb = node->ITRB.rb_right; \
|
||
|
} while (prev == rb); \
|
||
|
\
|
||
|
/* Check if the node intersects [start;last] */ \
|
||
|
if (last < ITSTART(node)) /* !Cond1 */ \
|
||
|
return NULL; \
|
||
|
else if (start <= ITLAST(node)) /* Cond2 */ \
|
||
|
return node; \
|
||
|
} \
|
||
|
}
|