RTree原始碼——C語言實現
RTree原始碼——C語言實現
cheungmine
一、什麼是RTree
“R樹是B樹向多維空間發展的另一種形式，它將空間物件按範圍劃分，每個結點都對應一個區域和一個磁碟頁，非葉結點的磁碟頁中儲存其所有子結點的區域範圍，非葉結點的所有子結點的區域都落在它的區域範圍之內；葉結點的磁碟頁中儲存其區域範圍之內的所有空間物件的外接矩形。每個結點所能擁有的子結點數目有上、下限，下限保證對磁碟空間的有效利用，上限保證每個結點對應一個磁碟頁，當插入新的結點導致某結點要求的空間大於一個磁碟頁時，該結點一分為二。R樹是一種動態索引結構，即：它的查詢可與插入或刪除同時進行，而且不需要定期地對樹結構進行重新組織。當更新一個關係並且在這個關係上正在做掃描時，如果更新影響到了掃描操作的任何一個頁，我們需要檢查掃描並且修復它。”
其實上面的話，你也不用多做研究。理解RTree是範圍樹，適合做空間索引（快速查詢）。更多的關於RTree的知識我也沒時間寫在這裡，我只知道原理，然後提供了下面的程式碼（經過我修改，看起來更順眼些）。一定要用它。感謝演算法的原作者和發明演算法的人。“帝國大廈的建立，人才更在資本之上”啊！
二、RTree的實現程式碼
本文的程式碼來源於GRASS，我根據自己的習慣，作了適當的修改，把原來多個檔案合成了2個檔案（rtree.h和rtree.c）。本文提供了完整的rtree實現程式碼和一個簡單的測試程式碼（test.c）。如果你發現什麼問題，請及時提交評論，以利改正。
RTree.h檔案：
/****************************************************************************
* RTree.H
*
* MODULE: R-Tree library
*
* AUTHOR(S): Antonin Guttman - original code
* Daniel Green (green@superliminal.com) - major clean-up
* and implementation of bounding spheres
*
* PURPOSE: Multi Dimensional Index
*
* COPYRIGHT: (C) 2001 by the GRASS Development Team
*
* This program is free software under the GNU General Public
* License (>=v2). Read the file COPYING that comes with GRASS
* for details.
*
* LAST MODIFY: ZhangLiang (cheungmine@gmail.com) - 2007-11
*****************************************************************************/
#ifndef RTREE_H_INCLUDED
#define RTREE_H_INCLUDED
/* PAGE_SIZE is normally the natural page size of the machine */
#define PAGE_SIZE 512
#define DIMS_NUMB 3 /* number of dimensions */
#define SIDES_NUMB 2*DIMS_NUMB
/* typedef float REALTYPE; */
typedef double REALTYPE;
#ifndef TRUE
#define TRUE 1
#define FALSE 0
#endif
typedef struct _RTREEMBR
{
REALTYPE bound[SIDES_NUMB]; /* xmin,ymin,...,xmax,ymax,... */
}RTREEMBR;
typedef struct _RTREEBRANCH
{
RTREEMBR mbr;
struct _RTREENODE *child; /* mbr id */
}RTREEBRANCH;
/* max branching factor of a node */
#define MAXCARD (int)((PAGE_SIZE-(2*sizeof(int))) / sizeof(RTREEBRANCH))
typedef struct _RTREENODE
{
int count;
int level; /* 0 is leaf, others positive */
RTREEBRANCH branch[MAXCARD];
}RTREENODE;
typedef struct _RTREELISTNODE
{
struct _RTREELISTNODE *next;
RTREENODE *node;
}RTREELISTNODE;
/*
* If passed to a tree search, this callback function will be called
* with the ID of each data mbr that overlaps the search mbr
* plus whatever user specific pointer was passed to the search.
* It can terminate the search early by returning 0 in which case
* the search will return the number of hits found up to that point.
*/
typedef int (*pfnSearchHitCallback)(int id, void* pfnParam);
int RTreeSetNodeMax(int new_max);
int RTreeSetLeafMax(int new_max);
int RTreeGetNodeMax(void);
int RTreeGetLeafMax(void);
/**
* Initialize a rectangle to have all 0 coordinates.
*/
void RTreeInitRect( RTREEMBR *rc);
/**
* Return a mbr whose first low side is higher than its opposite side -
* interpreted as an undefined mbr.
*/
RTREEMBR RTreeNullRect(void);
/**
* Print out the data for a rectangle.
*/
void RTreePrintRect( RTREEMBR *rc, int depth );
/**
* Calculate the 2-dimensional area of a rectangle
*/
REALTYPE RTreeRectArea( RTREEMBR *rc );
/**
* Calculate the n-dimensional volume of a rectangle
*/
REALTYPE RTreeRectVolume( RTREEMBR *rc );
/**
* Calculate the n-dimensional volume of the bounding sphere of a rectangle
* The exact volume of the bounding sphere for the given RTREEMBR.
*/
REALTYPE RTreeRectSphericalVolume( RTREEMBR *rc );
/**
* Calculate the n-dimensional surface area of a rectangle
*/
REALTYPE RTreeRectSurfaceArea( RTREEMBR *rc );
/**
* Combine two rectangles, make one that includes both.
*/
RTREEMBR RTreeCombineRect( RTREEMBR *rc1, RTREEMBR *rc2 );
/**
* Decide whether two rectangles overlap.
*/
int RTreeOverlap( RTREEMBR *rc1, RTREEMBR *rc2);
/**
* Decide whether rectangle r is contained in rectangle s.
*/
int RTreeContained( RTREEMBR *r, RTREEMBR *s);
/**
* Split a node.
* Divides the nodes branches and the extra one between two nodes.
* Old node is one of the new ones, and one really new one is created.
* Tries more than one method for choosing a partition, uses best result.
*/
void RTreeSplitNode( RTREENODE *node, RTREEBRANCH *br, RTREENODE **new_node);
/**
* Initialize a RTREENODE structure.
*/
void RTreeInitNode( RTREENODE *node );
/**
* Make a new node and initialize to have all branch cells empty.
*/
RTREENODE *RTreeNewNode(void);
void RTreeFreeNode( RTREENODE *node );
/**
* Print out the data in a node.
*/
void RTreePrintNode( RTREENODE *node, int depth );
/**
* Find the smallest rectangle that includes all rectangles in branches of a node.
*/
RTREEMBR RTreeNodeCover( RTREENODE *node );
/**
* Pick a branch. Pick the one that will need the smallest increase
* in area to accomodate the new rectangle. This will result in the
* least total area for the covering rectangles in the current node.
* In case of a tie, pick the one which was smaller before, to get
* the best resolution when searching.
*/
int RTreePickBranch( RTREEMBR *rc, RTREENODE *node);
/**
* Add a branch to a node. Split the node if necessary.
* Returns 0 if node not split. Old node updated.
* Returns 1 if node split, sets *new_node to address of new node.
* Old node updated, becomes one of two.
*/
int RTreeAddBranch( RTREEBRANCH *br, RTREENODE *node, RTREENODE **new_node);
/**
* Disconnect a dependent node.
*/
void RTreeDisconnectBranch( RTREENODE *node, int i );
/**
* Destroy (free) node recursively.
*/
void RTreeDestroyNode ( RTREENODE *node );
/**
* Create a new rtree index, empty. Consists of a single node.
*/
RTREENODE * RTreeCreate(void);
/**
* Destroy a rtree root must be a root of rtree. Free all memory.
*/
void RTreeDestroy(RTREENODE *root);
/**
* Search in an index tree or subtree for all data rectangles that overlap the argument rectangle.
* Return the number of qualifying data rects.
*/
int RTreeSearch( RTREENODE *node, RTREEMBR *rc, pfnSearchHitCallback pfnSHCB, void* pfnParam);
/**
* Insert a data rectangle into an index structure.
* RTreeInsertRect provides for splitting the root;
* returns 1 if root was split, 0 if it was not.
* The level argument specifies the number of steps up from the leaf
* level to insert; e.g. a data rectangle goes in at level = 0.
* _RTreeInsertRect does the recursion.
*/
int RTreeInsertRect( RTREEMBR *rc, int tid, RTREENODE **root, int level);
/**
* Delete a data rectangle from an index structure.
* Pass in a pointer to a RTREEMBR, the tid of the record, ptr to ptr to root node.
* Returns 1 if record not found, 0 if success.
* RTreeDeleteRect provides for eliminating the root.
*/
int RTreeDeleteRect( RTREEMBR *rc, int tid, RTREENODE **root);
#endif /* RTREE_H_INCLUDED */
* RTree.H
*
* MODULE: R-Tree library
*
* AUTHOR(S): Antonin Guttman - original code
* Daniel Green (green@superliminal.com) - major clean-up
* and implementation of bounding spheres
*
* PURPOSE: Multi Dimensional Index
*
* COPYRIGHT: (C) 2001 by the GRASS Development Team
*
* This program is free software under the GNU General Public
* License (>=v2). Read the file COPYING that comes with GRASS
* for details.
*
* LAST MODIFY: ZhangLiang (cheungmine@gmail.com) - 2007-11
*****************************************************************************/
#ifndef RTREE_H_INCLUDED
#define RTREE_H_INCLUDED
/* PAGE_SIZE is normally the natural page size of the machine */
#define PAGE_SIZE 512
#define DIMS_NUMB 3 /* number of dimensions */
#define SIDES_NUMB 2*DIMS_NUMB
/* typedef float REALTYPE; */
typedef double REALTYPE;
#ifndef TRUE
#define TRUE 1
#define FALSE 0
#endif
typedef struct _RTREEMBR
{
REALTYPE bound[SIDES_NUMB]; /* xmin,ymin,...,xmax,ymax,... */
}RTREEMBR;
typedef struct _RTREEBRANCH
{
RTREEMBR mbr;
struct _RTREENODE *child; /* mbr id */
}RTREEBRANCH;
/* max branching factor of a node */
#define MAXCARD (int)((PAGE_SIZE-(2*sizeof(int))) / sizeof(RTREEBRANCH))
typedef struct _RTREENODE
{
int count;
int level; /* 0 is leaf, others positive */
RTREEBRANCH branch[MAXCARD];
}RTREENODE;
typedef struct _RTREELISTNODE
{
struct _RTREELISTNODE *next;
RTREENODE *node;
}RTREELISTNODE;
/*
* If passed to a tree search, this callback function will be called
* with the ID of each data mbr that overlaps the search mbr
* plus whatever user specific pointer was passed to the search.
* It can terminate the search early by returning 0 in which case
* the search will return the number of hits found up to that point.
*/
typedef int (*pfnSearchHitCallback)(int id, void* pfnParam);
int RTreeSetNodeMax(int new_max);
int RTreeSetLeafMax(int new_max);
int RTreeGetNodeMax(void);
int RTreeGetLeafMax(void);
/**
* Initialize a rectangle to have all 0 coordinates.
*/
void RTreeInitRect( RTREEMBR *rc);
/**
* Return a mbr whose first low side is higher than its opposite side -
* interpreted as an undefined mbr.
*/
RTREEMBR RTreeNullRect(void);
/**
* Print out the data for a rectangle.
*/
void RTreePrintRect( RTREEMBR *rc, int depth );
/**
* Calculate the 2-dimensional area of a rectangle
*/
REALTYPE RTreeRectArea( RTREEMBR *rc );
/**
* Calculate the n-dimensional volume of a rectangle
*/
REALTYPE RTreeRectVolume( RTREEMBR *rc );
/**
* Calculate the n-dimensional volume of the bounding sphere of a rectangle
* The exact volume of the bounding sphere for the given RTREEMBR.
*/
REALTYPE RTreeRectSphericalVolume( RTREEMBR *rc );
/**
* Calculate the n-dimensional surface area of a rectangle
*/
REALTYPE RTreeRectSurfaceArea( RTREEMBR *rc );
/**
* Combine two rectangles, make one that includes both.
*/
RTREEMBR RTreeCombineRect( RTREEMBR *rc1, RTREEMBR *rc2 );
/**
* Decide whether two rectangles overlap.
*/
int RTreeOverlap( RTREEMBR *rc1, RTREEMBR *rc2);
/**
* Decide whether rectangle r is contained in rectangle s.
*/
int RTreeContained( RTREEMBR *r, RTREEMBR *s);
/**
* Split a node.
* Divides the nodes branches and the extra one between two nodes.
* Old node is one of the new ones, and one really new one is created.
* Tries more than one method for choosing a partition, uses best result.
*/
void RTreeSplitNode( RTREENODE *node, RTREEBRANCH *br, RTREENODE **new_node);
/**
* Initialize a RTREENODE structure.
*/
void RTreeInitNode( RTREENODE *node );
/**
* Make a new node and initialize to have all branch cells empty.
*/
RTREENODE *RTreeNewNode(void);
void RTreeFreeNode( RTREENODE *node );
/**
* Print out the data in a node.
*/
void RTreePrintNode( RTREENODE *node, int depth );
/**
* Find the smallest rectangle that includes all rectangles in branches of a node.
*/
RTREEMBR RTreeNodeCover( RTREENODE *node );
/**
* Pick a branch. Pick the one that will need the smallest increase
* in area to accomodate the new rectangle. This will result in the
* least total area for the covering rectangles in the current node.
* In case of a tie, pick the one which was smaller before, to get
* the best resolution when searching.
*/
int RTreePickBranch( RTREEMBR *rc, RTREENODE *node);
/**
* Add a branch to a node. Split the node if necessary.
* Returns 0 if node not split. Old node updated.
* Returns 1 if node split, sets *new_node to address of new node.
* Old node updated, becomes one of two.
*/
int RTreeAddBranch( RTREEBRANCH *br, RTREENODE *node, RTREENODE **new_node);
/**
* Disconnect a dependent node.
*/
void RTreeDisconnectBranch( RTREENODE *node, int i );
/**
* Destroy (free) node recursively.
*/
void RTreeDestroyNode ( RTREENODE *node );
/**
* Create a new rtree index, empty. Consists of a single node.
*/
RTREENODE * RTreeCreate(void);
/**
* Destroy a rtree root must be a root of rtree. Free all memory.
*/
void RTreeDestroy(RTREENODE *root);
/**
* Search in an index tree or subtree for all data rectangles that overlap the argument rectangle.
* Return the number of qualifying data rects.
*/
int RTreeSearch( RTREENODE *node, RTREEMBR *rc, pfnSearchHitCallback pfnSHCB, void* pfnParam);
/**
* Insert a data rectangle into an index structure.
* RTreeInsertRect provides for splitting the root;
* returns 1 if root was split, 0 if it was not.
* The level argument specifies the number of steps up from the leaf
* level to insert; e.g. a data rectangle goes in at level = 0.
* _RTreeInsertRect does the recursion.
*/
int RTreeInsertRect( RTREEMBR *rc, int tid, RTREENODE **root, int level);
/**
* Delete a data rectangle from an index structure.
* Pass in a pointer to a RTREEMBR, the tid of the record, ptr to ptr to root node.
* Returns 1 if record not found, 0 if success.
* RTreeDeleteRect provides for eliminating the root.
*/
int RTreeDeleteRect( RTREEMBR *rc, int tid, RTREENODE **root);
#endif /* RTREE_H_INCLUDED */
RTree.C檔案：
/****************************************************************************
* RTree.C
*
* MODULE: R-Tree library
*
* AUTHOR(S): Antonin Guttman - original code
* Daniel Green (green@superliminal.com) - major clean-up
* and implementation of bounding spheres
*
* PURPOSE: Multi Dimensional Index
*
* COPYRIGHT: (C) 2001 by the GRASS Development Team
*
* This program is free software under the GNU General Public
* License (>=v2). Read the file COPYING that comes with GRASS
* for details.
*
* LAST MODIFY: ZhangLiang (cheungmine@gmail.com) - 2007-11
*****************************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <float.h>
#include <math.h>
#include "rtree.h"
#define METHODS 1
/* variables for finding a partition */
typedef struct _RTREEPARTITION
{
int partition[MAXCARD+1];
int total;
int minfill;
int taken[MAXCARD+1];
int count[2];
RTREEMBR cover[2];
REALTYPE area[2];
} RTREEPARTITION;
RTREEBRANCH BranchBuf[MAXCARD+1];
int BranchCount;
RTREEMBR CoverSplit;
REALTYPE CoverSplitArea;
RTREEPARTITION Partitions[METHODS];
#define BIG_NUM (FLT_MAX/4.0)
#define INVALID_RECT(x) ((x)->bound[0] > (x)->bound[DIMS_NUMB])
#define MIN(a, b) ((a) < (b) ? (a) : (b))
#define MAX(a, b) ((a) > (b) ? (a) : (b))
int NODECARD = MAXCARD;
int LEAFCARD = MAXCARD;
/* balance criteria for node splitting */
/* NOTE: can be changed if needed. */
#define MINNODEFILL (NODECARD / 2)
#define MINLEAFFILL (LEAFCARD / 2)
#define MAXKIDS(n) ((n)->level > 0 ? NODECARD : LEAFCARD)
#define MINFILL(n) ((n)->level > 0 ? MINNODEFILL : MINLEAFFILL)
static int set_max(int *which, int new_max)
{
if(2 > new_max || new_max > MAXCARD)
return 0;
*which = new_max;
return 1;
}
/**
* Load branch buffer with branches from full node plus the extra branch.
*/
static void _RTreeGetBranches( RTREENODE *node, RTREEBRANCH *br)
{
int i;
assert(node && br);
/* load the branch buffer */
for (i=0; i<MAXKIDS(node); i++)
{
assert(node->branch[i].child); /* n should have every entry full */
BranchBuf[i] = node->branch[i];
}
BranchBuf[MAXKIDS(node)] = *br;
BranchCount = MAXKIDS(node) + 1;
/* calculate mbr containing all in the set */
CoverSplit = BranchBuf[0].mbr;
for (i=1; i<MAXKIDS(node)+1; i++)
{
CoverSplit = RTreeCombineRect(&CoverSplit, &BranchBuf[i].mbr);
}
CoverSplitArea = RTreeRectSphericalVolume(&CoverSplit);
RTreeInitNode(node);
}
/**
* Put a branch in one of the groups.
*/
static void _RTreeClassify(int i, int group, RTREEPARTITION *p)
{
assert(p);
assert(!p->taken[i]);
p->partition[i] = group;
p->taken[i] = TRUE;
if (p->count[group] == 0)
p->cover[group] = BranchBuf[i].mbr;
else
p->cover[group] = RTreeCombineRect(&BranchBuf[i].mbr, &p->cover[group]);
p->area[group] = RTreeRectSphericalVolume(&p->cover[group]);
p->count[group]++;
}
/**
* Pick two rects from set to be the first elements of the two groups.
* Pick the two that waste the most area if covered by a single rectangle.
*/
static void _RTreePickSeeds(RTREEPARTITION *p)
{
int i, j, seed0=0, seed1=0;
REALTYPE worst, waste, area[MAXCARD+1];
for (i=0; i<p->total; i++)
area[i] = RTreeRectSphericalVolume(&BranchBuf[i].mbr);
worst = -CoverSplitArea - 1;
for (i=0; i<p->total-1; i++)
{
for (j=i+1; j<p->total; j++)
{
RTREEMBR one_rect;
one_rect = RTreeCombineRect(&BranchBuf[i].mbr, &BranchBuf[j].mbr);
waste = RTreeRectSphericalVolume(&one_rect) - area[i] - area[j];
if (waste > worst)
{
worst = waste;
seed0 = i;
seed1 = j;
}
}
}
_RTreeClassify(seed0, 0, p);
_RTreeClassify(seed1, 1, p);
}
/**
* Copy branches from the buffer into two nodes according to the partition.
*/
static void _RTreeLoadNodes( RTREENODE *n, RTREENODE *q, RTREEPARTITION *p)
{
int i;
assert(n && q && p);
for (i=0; i<p->total; i++)
{
assert(p->partition[i] == 0 || p->partition[i] == 1);
if (p->partition[i] == 0)
RTreeAddBranch(&BranchBuf[i], n, NULL);
else if (p->partition[i] == 1)
RTreeAddBranch(&BranchBuf[i], q, NULL);
}
}
/**
* Initialize a RTREEPARTITION structure.
*/
static void _RTreeInitPart( RTREEPARTITION *p, int maxrects, int minfill)
{
int i;
assert(p);
p->count[0] = p->count[1] = 0;
p->cover[0] = p->cover[1] = RTreeNullRect();
p->area[0] = p->area[1] = (REALTYPE)0;
p->total = maxrects;
p->minfill = minfill;
for (i=0; i<maxrects; i++)
{
p->taken[i] = FALSE;
p->partition[i] = -1;
}
}
/**
* Print out data for a partition from RTREEPARTITION struct.
*/
static void _RTreePrintPart( RTREEPARTITION *p)
{
int i;
assert(p);
fprintf (stdout, " partition: ");
for (i=0; i<p->total; i++)
{
fprintf (stdout, "%3d ", i);
}
fprintf (stdout, " ");
for (i=0; i<p->total; i++)
{
if (p->taken[i])
fprintf (stdout, " t ");
else
fprintf (stdout, " ");
}
fprintf (stdout, " ");
for (i=0; i<p->total; i++)
{
fprintf (stdout, "%3d ", p->partition[i]);
}
fprintf (stdout, " ");
fprintf (stdout, "count[0] = %d area = %f ", p->count[0], p->area[0]);
fprintf (stdout, "count[1] = %d area = %f ", p->count[1], p->area[1]);
if (p->area[0] + p->area[1] > 0)
{
fprintf (stdout, "total area = %f effectiveness = %3.2f ",
p->area[0] + p->area[1], (float)CoverSplitArea / (p->area[0] + p->area[1]));
}
fprintf (stdout, "cover[0]: ");
RTreePrintRect(&p->cover[0], 0);
fprintf (stdout, "cover[1]: ");
RTreePrintRect(&p->cover[1], 0);
}
/**
* Method #0 for choosing a partition:
* As the seeds for the two groups, pick the two rects that would waste the
* most area if covered by a single rectangle, i.e. evidently the worst pair
* to have in the same group.
* Of the remaining, one at a time is chosen to be put in one of the two groups.
* The one chosen is the one with the greatest difference in area expansion
* depending on which group - the mbr most strongly attracted to one group
* and repelled from the other.
* If one group gets too full (more would force other group to violate min
* fill requirement) then other group gets the rest.
* These last are the ones that can go in either group most easily.
*/
static void _RTreeMethodZero( RTREEPARTITION *p, int minfill )
{
int i;
REALTYPE biggestDiff;
int group, chosen=0, betterGroup=0;
assert(p);
_RTreeInitPart(p, BranchCount, minfill);
_RTreePickSeeds(p);
while (p->count[0] + p->count[1] < p->total &&
p->count[0] < p->total - p->minfill &&
p->count[1] < p->total - p->minfill)
{
biggestDiff = (REALTYPE)-1.;
for (i=0; i<p->total; i++)
{
if (!p->taken[i])
{
RTREEMBR *r, rect_0, rect_1;
REALTYPE growth0, growth1, diff;
r = &BranchBuf[i].mbr;
rect_0 = RTreeCombineRect(r, &p->cover[0]);
rect_1 = RTreeCombineRect(r, &p->cover[1]);
growth0 = RTreeRectSphericalVolume(&rect_0) - p->area[0];
growth1 = RTreeRectSphericalVolume(&rect_1) - p->area[1];
diff = growth1 - growth0;
if (diff >= 0)
group = 0;
else
{
group = 1;
diff = -diff;
}
if (diff > biggestDiff)
{
biggestDiff = diff;
chosen = i;
betterGroup = group;
}
else if (diff==biggestDiff && p->count[group]<p->count[betterGroup])
{
chosen = i;
betterGroup = group;
}
}
}
_RTreeClassify(chosen, betterGroup, p);
}
/* if one group too full, put remaining rects in the other */
if (p->count[0] + p->count[1] < p->total)
{
if (p->count[0] >= p->total - p->minfill)
group = 1;
else
group = 0;
for (i=0; i<p->total; i++)
{
if (!p->taken[i])
_RTreeClassify(i, group, p);
}
}
assert(p->count[0] + p->count[1] == p->total);
assert(p->count[0] >= p->minfill && p->count[1] >= p->minfill);
}
/**
* Initialize one branch cell in a node.
*/
static void _RTreeInitBranch( RTREEBRANCH *br )
{
RTreeInitRect(&(br->mbr));
br->child = NULL;
}
static void _RTreePrintBranch( RTREEBRANCH *br, int depth )
{
RTreePrintRect(&(br->mbr), depth);
RTreePrintNode(br->child, depth);
}
/**
* Inserts a new data rectangle into the index structure.
* Recursively descends tree, propagates splits back up.
* Returns 0 if node was not split. Old node updated.
* If node was split, returns 1 and sets the pointer pointed to by
* new_node to point to the new node. Old node updated to become one of two.
* The level argument specifies the number of steps up from the leaf
* level to insert; e.g. a data rectangle goes in at level = 0.
*/
static int _RTreeInsertRect( RTREEMBR *rc, int tid, RTREENODE *node, RTREENODE **new_node, int level)
{
int i;
RTREEBRANCH b;
RTREENODE *n2;
assert(rc && node && new_node);
assert(level >= 0 && level <= node->level);
/* Still above level for insertion, go down tree recursively */
if (node->level > level)
{
i = RTreePickBranch(rc, node);
if (!_RTreeInsertRect(rc, tid, node->branch[i].child, &n2, level))
{
/* child was not split */
node->branch[i].mbr = RTreeCombineRect(rc, &(node->branch[i].mbr));
return 0;
}
/* child was split */
node->branch[i].mbr = RTreeNodeCover(node->branch[i].child);
b.child = n2;
b.mbr = RTreeNodeCover(n2);
return RTreeAddBranch(&b, node, new_node);
}
else if (node->level == level) /* Have reached level for insertion. Add mbr, split if necessary */
{
b.mbr = *rc;
#pragma warning(push) /* C4312 */
#pragma warning( disable : 4312 )
b.child = ( RTREENODE *) tid;
#pragma warning(pop)
/* child field of leaves contains tid of data record */
return RTreeAddBranch(&b, node, new_node);
}
/* Not supposed to happen */
assert (FALSE);
return 0;
}
/**
* Allocate space for a node in the list used in DeletRect to
* store Nodes that are too empty.
*/
static RTREELISTNODE * _RTreeNewListNode(void)
{
return (RTREELISTNODE *) malloc(sizeof(RTREELISTNODE));
}
static void _RTreeFreeListNode(RTREELISTNODE *p)
{
free(p);
}
/**
* Add a node to the reinsertion list. All its branches will later
* be reinserted into the index structure.
*/
static void _RTreeReInsert(RTREENODE *node, RTREELISTNODE **ne)
{
RTREELISTNODE *ln = _RTreeNewListNode();
ln->node = node;
ln->next = *ne;
*ne = ln;
}
/**
* Delete a rectangle from non-root part of an index structure.
* Called by RTreeDeleteRect. Descends tree recursively,
* merges branches on the way back up.
* Returns 1 if record not found, 0 if success.
*/
static int _RTreeDeleteRect( RTREEMBR *rc, int tid, RTREENODE *node, RTREELISTNODE **ee)
{
int i;
assert(rc && node && ee);
assert(tid >= 0);
assert(node->level >= 0);
if (node->level > 0) /* not a leaf node */
{
for (i = 0; i < NODECARD; i++)
{
if (node->branch[i].child && RTreeOverlap( rc, &(node->branch[i].mbr )))
{
if (!_RTreeDeleteRect( rc, tid, node->branch[i].child, ee ))
{
if (node->branch[i].child->count >= MINNODEFILL)
node->branch[i].mbr = RTreeNodeCover( node->branch[i].child );
else{ /* not enough entries in child, eliminate child node */
_RTreeReInsert(node->branch[i].child, ee);
RTreeDisconnectBranch(node, i);
}
return 0;
}
}
}
return 1;
}
#pragma warning(push) /* C4312 */
#pragma warning( disable : 4312 )
/* a leaf node */
for (i = 0; i < LEAFCARD; i++)
{
if ( node->branch[i].child && node->branch[i].child == (RTREENODE *) tid )
{
RTreeDisconnectBranch( node, i );
return 0;
}
}
#pragma warning(pop)
return 1;
}
static void _RTreeTabIn(int depth)
{
int i;
for(i=0; i<depth; i++)
putchar(' ');
}
/*=============================================================================
Public functions:
=============================================================================*/
int RTreeSetNodeMax(int new_max) { return set_max(&NODECARD, new_max); }
int RTreeSetLeafMax(int new_max) { return set_max(&LEAFCARD, new_max); }
int RTreeGetNodeMax(void) { return NODECARD; }
int RTreeGetLeafMax(void) { return LEAFCARD; }
/**
* Initialize a rectangle to have all 0 coordinates.
*/
void RTreeInitRect( RTREEMBR *rc)
{
int i;
for (i=0; i<SIDES_NUMB; i++)
rc->bound[i] = (REALTYPE) 0;
}
/**
* Return a mbr whose first low side is higher than its opposite side -
* interpreted as an undefined mbr.
*/
RTREEMBR RTreeNullRect(void)
{
RTREEMBR rc;
int i;
rc.bound[0] = (REALTYPE) 1;
rc.bound[DIMS_NUMB] = (REALTYPE)-1;
for (i=1; i<DIMS_NUMB; i++)
rc.bound[i] = rc.bound[i+DIMS_NUMB] = (REALTYPE) 0;
return rc;
}
/**
* Print out the data for a rectangle.
*/
void RTreePrintRect( RTREEMBR *rc, int depth)
{
int i;
_RTreeTabIn(depth);
fprintf (stdout, "mbr: ");
for (i = 0; i < DIMS_NUMB; i++)
{
_RTreeTabIn(depth+1);
fprintf (stdout, "%f %f ", rc->bound[i], rc->bound[i + DIMS_NUMB]);
}
}
/**
* Calculate the 2-dimensional area of a rectangle
*/
REALTYPE RTreeRectArea( RTREEMBR *rc )
{
if (INVALID_RECT(rc))
return (REALTYPE) 0;
return (rc->bound[DIMS_NUMB] - rc->bound[0]) * (rc->bound[DIMS_NUMB+1] - rc->bound[1]);
}
/**
* Calculate the n-dimensional volume of a rectangle
*/
REALTYPE RTreeRectVolume( RTREEMBR *rc )
{
int i;
REALTYPE vol = (REALTYPE) 1;
if (INVALID_RECT(rc))
return (REALTYPE) 0;
for(i=0; i<DIMS_NUMB; i++)
vol *= (rc->bound[i+DIMS_NUMB] - rc->bound[i]);
assert(vol >= 0.0);
return vol;
}
/**
* Precomputed volumes of the unit spheres for the first few dimensions
*/
const double UnitSphereVolumes[] = {
0.000000, /* dimension 0 */
2.000000, /* dimension 1 */
3.141593, /* dimension 2 */
4.188790, /* dimension 3 */
4.934802, /* dimension 4 */
5.263789, /* dimension 5 */
5.167713, /* dimension 6 */
4.724766, /* dimension 7 */
4.058712, /* dimension 8 */
3.298509, /* dimension 9 */
2.550164, /* dimension 10 */
1.884104, /* dimension 11 */
1.335263, /* dimension 12 */
0.910629, /* dimension 13 */
0.599265, /* dimension 14 */
0.381443, /* dimension 15 */
0.235331, /* dimension 16 */
0.140981, /* dimension 17 */
0.082146, /* dimension 18 */
0.046622, /* dimension 19 */
0.025807, /* dimension 20 */
};
#if DIMS_NUMB > 20
#error "not enough precomputed sphere volumes"
#endif
#define UnitSphereVolume UnitSphereVolumes[DIMS_NUMB]
/**
* Calculate the n-dimensional volume of the bounding sphere of a rectangle.
* The exact volume of the bounding sphere for the given RTREEMBR.
*/
REALTYPE RTreeRectSphericalVolume( RTREEMBR *rc )
{
int i;
double sum_of_squares=0, radius;
if (INVALID_RECT(rc))
return (REALTYPE) 0;
for (i=0; i<DIMS_NUMB; i++) {
double half_extent = (rc->bound[i+DIMS_NUMB] - rc->bound[i]) / 2;
sum_of_squares += half_extent * half_extent;
}
radius = sqrt(sum_of_squares);
return (REALTYPE)(pow(radius, DIMS_NUMB) * UnitSphereVolume);
}
/**
* Calculate the n-dimensional surface area of a rectangle
*/
REALTYPE RTreeRectSurfaceArea( RTREEMBR *rc )
{
int i, j;
REALTYPE sum = (REALTYPE) 0;
if (INVALID_RECT(rc))
return (REALTYPE) 0;
for (i=0; i<DIMS_NUMB; i++) {
REALTYPE face_area = (REALTYPE)1;
for (j=0; j<DIMS_NUMB; j++)
/* exclude i extent from product in this dimension */
if(i != j) {
REALTYPE j_extent = rc->bound[j+DIMS_NUMB] - rc->bound[j];
face_area *= j_extent;
}
sum += face_area;
}
return 2 * sum;
}
/**
* Combine two rectangles, make one that includes both.
*/
RTREEMBR RTreeCombineRect( RTREEMBR *rc1, RTREEMBR *rc2 )
{
int i, j;
RTREEMBR new_rect;
assert(rc1 && rc2);
if (INVALID_RECT(rc1))
return *rc2;
if (INVALID_RECT(rc2))
return *rc1;
for (i = 0; i < DIMS_NUMB; i++)
{
new_rect.bound[i] = MIN(rc1->bound[i], rc2->bound[i]);
j = i + DIMS_NUMB;
new_rect.bound[j] = MAX(rc1->bound[j], rc2->bound[j]);
}
return new_rect;
}
/**
* Decide whether two rectangles overlap.
*/
int RTreeOverlap( RTREEMBR *rc1, RTREEMBR *rc2)
{
int i, j;
assert(rc1 && rc2);
for (i=0; i<DIMS_NUMB; i++)
{
j = i + DIMS_NUMB; /* index for high sides */
if (rc1->bound[i] > rc2->bound[j] || rc2->bound[i] > rc1->bound[j])
return FALSE;
}
return TRUE;
}
/**
* Decide whether rectangle r is contained in rectangle s.
*/
int RTreeContained( RTREEMBR *r, RTREEMBR *s)
{
int i, j, result;
assert(r && s);
/* undefined mbr is contained in any other */
if (INVALID_RECT(r))
return TRUE;
/* no mbr (except an undefined one) is contained in an undef mbr */
if (INVALID_RECT(s))
return FALSE;
result = TRUE;
for (i = 0; i < DIMS_NUMB; i++)
{
j = i + DIMS_NUMB; /* index for high sides */
result = result && r->bound[i] >= s->bound[i] && r->bound[j] <= s->bound[j];
}
return result;
}
/**
* Split a node.
* Divides the nodes branches and the extra one between two nodes.
* Old node is one of the new ones, and one really new one is created.
* Tries more than one method for choosing a partition, uses best result.
*/
void RTreeSplitNode( RTREENODE *node, RTREEBRANCH *br, RTREENODE **new_node)
{
RTREEPARTITION *p;
int level;
assert(node && br);
/* load all the branches into a buffer, initialize old node */
level = node->level;
_RTreeGetBranches(node, br);
/* find partition */
p = &Partitions[0];
/* Note: can't use MINFILL(n) below since node was cleared by GetBranches() */
_RTreeMethodZero(p, level>0 ? MINNODEFILL : MINLEAFFILL);
/* put branches from buffer into 2 nodes according to chosen partition */
*new_node = RTreeNewNode();
(*new_node)->level = node->level = level;
_RTreeLoadNodes(node, *new_node, p);
assert(node->count+(*new_node)->count == p->total);
}
/**
* Initialize a RTREENODE structure.
*/
void RTreeInitNode( RTREENODE *node )
{
int i;
node->count = 0;
node->level = -1;
for (i = 0; i < MAXCARD; i++)
_RTreeInitBranch(&(node->branch[i]));
}
/**
* Make a new node and initialize to have all branch cells empty.
*/
RTREENODE *RTreeNewNode(void)
{
RTREENODE *node = (RTREENODE*) malloc(sizeof(RTREENODE));
assert(node);
RTreeInitNode(node);
return node;
}
void RTreeFreeNode( RTREENODE *node )
{
assert(node);
free(node);
}
/**
* Print out the data in a node.
*/
void RTreePrintNode( RTREENODE *node, int depth )
{
int i;
assert(node);
_RTreeTabIn(depth);
fprintf (stdout, "node");
if (node->level == 0)
fprintf (stdout, " LEAF");
else if (node->level > 0)
fprintf (stdout, " NONLEAF");
else
fprintf (stdout, " TYPE=?");
#pragma warning(push) /* C4311 */
#pragma warning( disable : 4311 )
fprintf (stdout, " level=%d count=%d address=%o ", node->level, node->count, (unsigned int) node);
#pragma warning(pop)
for (i=0; i<node->count; i++)
{
if(node->level == 0) {
/* _RTreeTabIn(depth); */
/* fprintf (stdout, " %d: data = %d ", i, n->branch[i].child); */
}
else {
_RTreeTabIn(depth);
fprintf (stdout, "branch %d ", i);
_RTreePrintBranch(&node->branch[i], depth+1);
}
}
}
/**
* Find the smallest rectangle that includes all rectangles in branches of a node.
*/
RTREEMBR RTreeNodeCover( RTREENODE *node )
{
int i, first_time=1;
RTREEMBR rc;
assert(node);
RTreeInitRect(&rc);
for (i = 0; i < MAXKIDS(node); i++)
{
if (node->branch[i].child)
{
if (first_time)
{
rc = node->branch[i].mbr;
first_time = 0;
}
else
rc = RTreeCombineRect(&rc, &(node->branch[i].mbr));
}
}
return rc;
}
/**
* Pick a branch. Pick the one that will need the smallest increase
* in area to accomodate the new rectangle. This will result in the
* least total area for the covering rectangles in the current node.
* In case of a tie, pick the one which was smaller before, to get
* the best resolution when searching.
*/
int RTreePickBranch( RTREEMBR *rc, RTREENODE *node)
{
RTREEMBR *r;
int i, first_time = 1;
REALTYPE increase, bestIncr=(REALTYPE)-1, area, bestArea=0;
int best=0;
RTREEMBR tmp_rect;
assert(rc && node);
for (i=0; i<MAXKIDS(node); i++)
{
if (node->branch[i].child)
{
r = &node->branch[i].mbr;
area = RTreeRectSphericalVolume(r);
tmp_rect = RTreeCombineRect(rc, r);
increase = RTreeRectSphericalVolume(&tmp_rect) - area;
if (increase < bestIncr || first_time)
{
best = i;
bestArea = area;
bestIncr = increase;
first_time = 0;
}
else if (increase == bestIncr && area < bestArea)
{
best = i;
bestArea = area;
bestIncr = increase;
}
}
}
return best;
}
/**
* Add a branch to a node. Split the node if necessary.
* Returns 0 if node not split. Old node updated.
* Returns 1 if node split, sets *new_node to address of new node.
* Old node updated, becomes one of two.
*/
int RTreeAddBranch( RTREEBRANCH *br, RTREENODE *node, RTREENODE **new_node)
{
int i;
assert(br && node);
if (node->count < MAXKIDS(node)) /* split won't be necessary */
{
for (i = 0; i < MAXKIDS(node); i++) /* find empty branch */
{
if (node->branch[i].child == NULL)
{
node->branch[i] = *br;
node->count++;
break;
}
}
return 0;
}
assert(new_node);
RTreeSplitNode(node, br, new_node);
return 1;
}
/**
* Disconnect a dependent node.
*/
void RTreeDisconnectBranch( RTREENODE *node, int i )
{
assert(node && i>=0 && i<MAXKIDS(node));
assert(node->branch[i].child);
_RTreeInitBranch(&(node->branch[i]));
node->count--;
}
/**
* Destroy (free) node recursively.
*/
void RTreeDestroyNode ( RTREENODE *node )
{
int i;
if (node->level > 0)
{
/* it is not leaf -> destroy childs */
for ( i = 0; i < NODECARD; i++)
{
if ( node->branch[i].child )
RTreeDestroyNode ( node->branch[i].child );
}
}
/* Free this node */
RTreeFreeNode( node );
}
/**
* Create a new rtree index, empty. Consists of a single node.
*/
RTREENODE * RTreeCreate(void)
{
RTREENODE * root = RTreeNewNode();
root->level = 0; /* leaf */
return root;
}
/**
* Destroy a rtree root must be a root of rtree. Free all memory.
*/
void RTreeDestroy(RTREENODE *root)
{
RTreeDestroyNode (root);
}
/**
* Search in an index tree or subtree for all data rectangles that overlap the argument rectangle.
* Return the number of qualifying data rects.
*/
int RTreeSearch( RTREENODE *node, RTREEMBR *rc, pfnSearchHitCallback pfnSHCB, void* pfnParam)
{
/* Fix not yet tested. */
int hitCount = 0;
int i;
assert(node && rc);
assert(node->level >= 0);
if (node->level > 0) /* this is an internal node in the tree */
{
for (i=0; i<NODECARD; i++){
if (node->branch[i].child && RTreeOverlap(rc, &node->branch[i].mbr))
hitCount += RTreeSearch(node->branch[i].child, rc, pfnSHCB, pfnParam);
}
}
else /* this is a leaf node */
{
#pragma warning(push) /* C4311 */
#pragma warning( disable : 4311 )
for (i=0; i<LEAFCARD; i++)
{
if (node->branch[i].child && RTreeOverlap(rc, &node->branch[i].mbr))
{
hitCount++;
/* call the user-provided callback and return if callback wants to terminate search early */
if(pfnSHCB && ! pfnSHCB((int)node->branch[i].child, pfnParam) )
return hitCount;
}
}
#pragma warning(pop)
}
return hitCount;
}
/**
* Insert a data rectangle into an index structure.
* RTreeInsertRect provides for splitting the root;
* returns 1 if root was split, 0 if it was not.
* The level argument specifies the number of steps up from the leaf
* level to insert; e.g. a data rectangle goes in at level = 0.
* _RTreeInsertRect does the recursion.
*/
int RTreeInsertRect( RTREEMBR *rc, int tid, RTREENODE **root, int level)
{
#ifdef _DEBUG
int i;
#endif
RTREENODE *newroot;
RTREENODE *newnode;
RTREEBRANCH b;
assert(rc && root);
assert(level >= 0 && level <= (*root)->level);
#ifdef _DEBUG
for (i=0; i<DIMS_NUMB; i++)
assert(rc->bound[i] <= rc->bound[DIMS_NUMB+i]);
#endif
/* root split */
if (_RTreeInsertRect(rc, tid, *root, &newnode, level))
{
newroot = RTreeNewNode(); /* grow a new root, & tree taller */
newroot->level = (*root)->level + 1;
b.mbr = RTreeNodeCover(*root);
b.child = *root;
RTreeAddBranch(&b, newroot, NULL);
b.mbr = RTreeNodeCover(newnode);
b.child = newnode;
RTreeAddBranch(&b, newroot, NULL);
*root = newroot;
return 1;
}
return 0;
}
/**
* Delete a data rectangle from an index structure.
* Pass in a pointer to a RTREEMBR, the tid of the record, ptr to ptr to root node.
* Returns 1 if record not found, 0 if success.
* RTreeDeleteRect provides for eliminating the root.
*/
int RTreeDeleteRect( RTREEMBR *rc, int tid, RTREENODE **root)
{
int i;
RTREENODE *tmp_nptr = NULL;
RTREELISTNODE *reInsertList = NULL;
RTREELISTNODE *e;
assert(rc && root);
assert(*root);
assert(tid >= 0);
if (!_RTreeDeleteRect(rc, tid, *root, &reInsertList))
{
/* found and deleted a data item */
/* reinsert any branches from eliminated nodes */
while (reInsertList)
{
tmp_nptr = reInsertList->node;
#pragma warning(push) /* C4311 */
#pragma warning( disable : 4311 )
for (i = 0; i < MAXKIDS(tmp_nptr); i++)
{
if (tmp_nptr->branch[i].child)
{
RTreeInsertRect(&(tmp_nptr->branch[i].mbr), (int)tmp_nptr->branch[i].child, root, tmp_nptr->level);
}
}
#pragma warning(pop)
e = reInsertList;
reInsertList = reInsertList->next;
RTreeFreeNode(e->node);
_RTreeFreeListNode(e);
}
/* check for redundant root (not leaf, 1 child) and eliminate */
if ((*root)->count == 1 && (*root)->level > 0)
{
for (i = 0; i < NODECARD; i++)
{
tmp_nptr = (*root)->branch[i].child;
if(tmp_nptr)
break;
}
assert(tmp_nptr);
RTreeFreeNode(*root);
*root = tmp_nptr;
}
return 0;
}
return 1;
}
* RTree.C
*
* MODULE: R-Tree library
*
* AUTHOR(S): Antonin Guttman - original code
* Daniel Green (green@superliminal.com) - major clean-up
* and implementation of bounding spheres
*
* PURPOSE: Multi Dimensional Index
*
* COPYRIGHT: (C) 2001 by the GRASS Development Team
*
* This program is free software under the GNU General Public
* License (>=v2). Read the file COPYING that comes with GRASS
* for details.
*
* LAST MODIFY: ZhangLiang (cheungmine@gmail.com) - 2007-11
*****************************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <float.h>
#include <math.h>
#include "rtree.h"
#define METHODS 1
/* variables for finding a partition */
typedef struct _RTREEPARTITION
{
int partition[MAXCARD+1];
int total;
int minfill;
int taken[MAXCARD+1];
int count[2];
RTREEMBR cover[2];
REALTYPE area[2];
} RTREEPARTITION;
RTREEBRANCH BranchBuf[MAXCARD+1];
int BranchCount;
RTREEMBR CoverSplit;
REALTYPE CoverSplitArea;
RTREEPARTITION Partitions[METHODS];
#define BIG_NUM (FLT_MAX/4.0)
#define INVALID_RECT(x) ((x)->bound[0] > (x)->bound[DIMS_NUMB])
#define MIN(a, b) ((a) < (b) ? (a) : (b))
#define MAX(a, b) ((a) > (b) ? (a) : (b))
int NODECARD = MAXCARD;
int LEAFCARD = MAXCARD;
/* balance criteria for node splitting */
/* NOTE: can be changed if needed. */
#define MINNODEFILL (NODECARD / 2)
#define MINLEAFFILL (LEAFCARD / 2)
#define MAXKIDS(n) ((n)->level > 0 ? NODECARD : LEAFCARD)
#define MINFILL(n) ((n)->level > 0 ? MINNODEFILL : MINLEAFFILL)
static int set_max(int *which, int new_max)
{
if(2 > new_max || new_max > MAXCARD)
return 0;
*which = new_max;
return 1;
}
/**
* Load branch buffer with branches from full node plus the extra branch.
*/
static void _RTreeGetBranches( RTREENODE *node, RTREEBRANCH *br)
{
int i;
assert(node && br);
/* load the branch buffer */
for (i=0; i<MAXKIDS(node); i++)
{
assert(node->branch[i].child); /* n should have every entry full */
BranchBuf[i] = node->branch[i];
}
BranchBuf[MAXKIDS(node)] = *br;
BranchCount = MAXKIDS(node) + 1;
/* calculate mbr containing all in the set */
CoverSplit = BranchBuf[0].mbr;
for (i=1; i<MAXKIDS(node)+1; i++)
{
CoverSplit = RTreeCombineRect(&CoverSplit, &BranchBuf[i].mbr);
}
CoverSplitArea = RTreeRectSphericalVolume(&CoverSplit);
RTreeInitNode(node);
}
/**
* Put a branch in one of the groups.
*/
static void _RTreeClassify(int i, int group, RTREEPARTITION *p)
{
assert(p);
assert(!p->taken[i]);
p->partition[i] = group;
p->taken[i] = TRUE;
if (p->count[group] == 0)
p->cover[group] = BranchBuf[i].mbr;
else
p->cover[group] = RTreeCombineRect(&BranchBuf[i].mbr, &p->cover[group]);
p->area[group] = RTreeRectSphericalVolume(&p->cover[group]);
p->count[group]++;
}
/**
* Pick two rects from set to be the first elements of the two groups.
* Pick the two that waste the most area if covered by a single rectangle.
*/
static void _RTreePickSeeds(RTREEPARTITION *p)
{
int i, j, seed0=0, seed1=0;
REALTYPE worst, waste, area[MAXCARD+1];
for (i=0; i<p->total; i++)
area[i] = RTreeRectSphericalVolume(&BranchBuf[i].mbr);
worst = -CoverSplitArea - 1;
for (i=0; i<p->total-1; i++)
{
for (j=i+1; j<p->total; j++)
{
RTREEMBR one_rect;
one_rect = RTreeCombineRect(&BranchBuf[i].mbr, &BranchBuf[j].mbr);
waste = RTreeRectSphericalVolume(&one_rect) - area[i] - area[j];
if (waste > worst)
{
worst = waste;
seed0 = i;
seed1 = j;
}
}
}
_RTreeClassify(seed0, 0, p);
_RTreeClassify(seed1, 1, p);
}
/**
* Copy branches from the buffer into two nodes according to the partition.
*/
static void _RTreeLoadNodes( RTREENODE *n, RTREENODE *q, RTREEPARTITION *p)
{
int i;
assert(n && q && p);
for (i=0; i<p->total; i++)
{
assert(p->partition[i] == 0 || p->partition[i] == 1);
if (p->partition[i] == 0)
RTreeAddBranch(&BranchBuf[i], n, NULL);
else if (p->partition[i] == 1)
RTreeAddBranch(&BranchBuf[i], q, NULL);
}
}
/**
* Initialize a RTREEPARTITION structure.
*/
static void _RTreeInitPart( RTREEPARTITION *p, int maxrects, int minfill)
{
int i;
assert(p);
p->count[0] = p->count[1] = 0;
p->cover[0] = p->cover[1] = RTreeNullRect();
p->area[0] = p->area[1] = (REALTYPE)0;
p->total = maxrects;
p->minfill = minfill;
for (i=0; i<maxrects; i++)
{
p->taken[i] = FALSE;
p->partition[i] = -1;
}
}
/**
* Print out data for a partition from RTREEPARTITION struct.
*/
static void _RTreePrintPart( RTREEPARTITION *p)
{
int i;
assert(p);
fprintf (stdout, " partition: ");
for (i=0; i<p->total; i++)
{
fprintf (stdout, "%3d ", i);
}
fprintf (stdout, " ");
for (i=0; i<p->total; i++)
{
if (p->taken[i])
fprintf (stdout, " t ");
else
fprintf (stdout, " ");
}
fprintf (stdout, " ");
for (i=0; i<p->total; i++)
{
fprintf (stdout, "%3d ", p->partition[i]);
}
fprintf (stdout, " ");
fprintf (stdout, "count[0] = %d area = %f ", p->count[0], p->area[0]);
fprintf (stdout, "count[1] = %d area = %f ", p->count[1], p->area[1]);
if (p->area[0] + p->area[1] > 0)
{
fprintf (stdout, "total area = %f effectiveness = %3.2f ",
p->area[0] + p->area[1], (float)CoverSplitArea / (p->area[0] + p->area[1]));
}
fprintf (stdout, "cover[0]: ");
RTreePrintRect(&p->cover[0], 0);
fprintf (stdout, "cover[1]: ");
RTreePrintRect(&p->cover[1], 0);
}
/**
* Method #0 for choosing a partition:
* As the seeds for the two groups, pick the two rects that would waste the
* most area if covered by a single rectangle, i.e. evidently the worst pair
* to have in the same group.
* Of the remaining, one at a time is chosen to be put in one of the two groups.
* The one chosen is the one with the greatest difference in area expansion
* depending on which group - the mbr most strongly attracted to one group
* and repelled from the other.
* If one group gets too full (more would force other group to violate min
* fill requirement) then other group gets the rest.
* These last are the ones that can go in either group most easily.
*/
static void _RTreeMethodZero( RTREEPARTITION *p, int minfill )
{
int i;
REALTYPE biggestDiff;
int group, chosen=0, betterGroup=0;
assert(p);
_RTreeInitPart(p, BranchCount, minfill);
_RTreePickSeeds(p);
while (p->count[0] + p->count[1] < p->total &&
p->count[0] < p->total - p->minfill &&
p->count[1] < p->total - p->minfill)
{
biggestDiff = (REALTYPE)-1.;
for (i=0; i<p->total; i++)
{
if (!p->taken[i])
{
RTREEMBR *r, rect_0, rect_1;
REALTYPE growth0, growth1, diff;
r = &BranchBuf[i].mbr;
rect_0 = RTreeCombineRect(r, &p->cover[0]);
rect_1 = RTreeCombineRect(r, &p->cover[1]);
growth0 = RTreeRectSphericalVolume(&rect_0) - p->area[0];
growth1 = RTreeRectSphericalVolume(&rect_1) - p->area[1];
diff = growth1 - growth0;
if (diff >= 0)
group = 0;
else
{
group = 1;
diff = -diff;
}
if (diff > biggestDiff)
{
biggestDiff = diff;
chosen = i;
betterGroup = group;
}
else if (diff==biggestDiff && p->count[group]<p->count[betterGroup])
{
chosen = i;
betterGroup = group;
}
}
}
_RTreeClassify(chosen, betterGroup, p);
}
/* if one group too full, put remaining rects in the other */
if (p->count[0] + p->count[1] < p->total)
{
if (p->count[0] >= p->total - p->minfill)
group = 1;
else
group = 0;
for (i=0; i<p->total; i++)
{
if (!p->taken[i])
_RTreeClassify(i, group, p);
}
}
assert(p->count[0] + p->count[1] == p->total);
assert(p->count[0] >= p->minfill && p->count[1] >= p->minfill);
}
/**
* Initialize one branch cell in a node.
*/
static void _RTreeInitBranch( RTREEBRANCH *br )
{
RTreeInitRect(&(br->mbr));
br->child = NULL;
}
static void _RTreePrintBranch( RTREEBRANCH *br, int depth )
{
RTreePrintRect(&(br->mbr), depth);
RTreePrintNode(br->child, depth);
}
/**
* Inserts a new data rectangle into the index structure.
* Recursively descends tree, propagates splits back up.
* Returns 0 if node was not split. Old node updated.
* If node was split, returns 1 and sets the pointer pointed to by
* new_node to point to the new node. Old node updated to become one of two.
* The level argument specifies the number of steps up from the leaf
* level to insert; e.g. a data rectangle goes in at level = 0.
*/
static int _RTreeInsertRect( RTREEMBR *rc, int tid, RTREENODE *node, RTREENODE **new_node, int level)
{
int i;
RTREEBRANCH b;
RTREENODE *n2;
assert(rc && node && new_node);
assert(level >= 0 && level <= node->level);
/* Still above level for insertion, go down tree recursively */
if (node->level > level)
{
i = RTreePickBranch(rc, node);
if (!_RTreeInsertRect(rc, tid, node->branch[i].child, &n2, level))
{
/* child was not split */
node->branch[i].mbr = RTreeCombineRect(rc, &(node->branch[i].mbr));
return 0;
}
/* child was split */
node->branch[i].mbr = RTreeNodeCover(node->branch[i].child);
b.child = n2;
b.mbr = RTreeNodeCover(n2);
return RTreeAddBranch(&b, node, new_node);
}
else if (node->level == level) /* Have reached level for insertion. Add mbr, split if necessary */
{
b.mbr = *rc;
#pragma warning(push) /* C4312 */
#pragma warning( disable : 4312 )
b.child = ( RTREENODE *) tid;
#pragma warning(pop)
/* child field of leaves contains tid of data record */
return RTreeAddBranch(&b, node, new_node);
}
/* Not supposed to happen */
assert (FALSE);
return 0;
}
/**
* Allocate space for a node in the list used in DeletRect to
* store Nodes that are too empty.
*/
static RTREELISTNODE * _RTreeNewListNode(void)
{
return (RTREELISTNODE *) malloc(sizeof(RTREELISTNODE));
}
static void _RTreeFreeListNode(RTREELISTNODE *p)
{
free(p);
}
/**
* Add a node to the reinsertion list. All its branches will later
* be reinserted into the index structure.
*/
static void _RTreeReInsert(RTREENODE *node, RTREELISTNODE **ne)
{
RTREELISTNODE *ln = _RTreeNewListNode();
ln->node = node;
ln->next = *ne;
*ne = ln;
}
/**
* Delete a rectangle from non-root part of an index structure.
* Called by RTreeDeleteRect. Descends tree recursively,
* merges branches on the way back up.
* Returns 1 if record not found, 0 if success.
*/
static int _RTreeDeleteRect( RTREEMBR *rc, int tid, RTREENODE *node, RTREELISTNODE **ee)
{
int i;
assert(rc && node && ee);
assert(tid >= 0);
assert(node->level >= 0);
if (node->level > 0) /* not a leaf node */
{
for (i = 0; i < NODECARD; i++)
{
if (node->branch[i].child && RTreeOverlap( rc, &(node->branch[i].mbr )))
{
if (!_RTreeDeleteRect( rc, tid, node->branch[i].child, ee ))
{
if (node->branch[i].child->count >= MINNODEFILL)
node->branch[i].mbr = RTreeNodeCover( node->branch[i].child );
else{ /* not enough entries in child, eliminate child node */
_RTreeReInsert(node->branch[i].child, ee);
RTreeDisconnectBranch(node, i);
}
return 0;
}
}
}
return 1;
}
#pragma warning(push) /* C4312 */
#pragma warning( disable : 4312 )
/* a leaf node */
for (i = 0; i < LEAFCARD; i++)
{
if ( node->branch[i].child && node->branch[i].child == (RTREENODE *) tid )
{
RTreeDisconnectBranch( node, i );
return 0;
}
}
#pragma warning(pop)
return 1;
}
static void _RTreeTabIn(int depth)
{
int i;
for(i=0; i<depth; i++)
putchar(' ');
}
/*=============================================================================
Public functions:
=============================================================================*/
int RTreeSetNodeMax(int new_max) { return set_max(&NODECARD, new_max); }
int RTreeSetLeafMax(int new_max) { return set_max(&LEAFCARD, new_max); }
int RTreeGetNodeMax(void) { return NODECARD; }
int RTreeGetLeafMax(void) { return LEAFCARD; }
/**
* Initialize a rectangle to have all 0 coordinates.
*/
void RTreeInitRect( RTREEMBR *rc)
{
int i;
for (i=0; i<SIDES_NUMB; i++)
rc->bound[i] = (REALTYPE) 0;
}
/**
* Return a mbr whose first low side is higher than its opposite side -
* interpreted as an undefined mbr.
*/
RTREEMBR RTreeNullRect(void)
{
RTREEMBR rc;
int i;
rc.bound[0] = (REALTYPE) 1;
rc.bound[DIMS_NUMB] = (REALTYPE)-1;
for (i=1; i<DIMS_NUMB; i++)
rc.bound[i] = rc.bound[i+DIMS_NUMB] = (REALTYPE) 0;
return rc;
}
/**
* Print out the data for a rectangle.
*/
void RTreePrintRect( RTREEMBR *rc, int depth)
{
int i;
_RTreeTabIn(depth);
fprintf (stdout, "mbr: ");
for (i = 0; i < DIMS_NUMB; i++)
{
_RTreeTabIn(depth+1);
fprintf (stdout, "%f %f ", rc->bound[i], rc->bound[i + DIMS_NUMB]);
}
}
/**
* Calculate the 2-dimensional area of a rectangle
*/
REALTYPE RTreeRectArea( RTREEMBR *rc )
{
if (INVALID_RECT(rc))
return (REALTYPE) 0;
return (rc->bound[DIMS_NUMB] - rc->bound[0]) * (rc->bound[DIMS_NUMB+1] - rc->bound[1]);
}
/**
* Calculate the n-dimensional volume of a rectangle
*/
REALTYPE RTreeRectVolume( RTREEMBR *rc )
{
int i;
REALTYPE vol = (REALTYPE) 1;
if (INVALID_RECT(rc))
return (REALTYPE) 0;
for(i=0; i<DIMS_NUMB; i++)
vol *= (rc->bound[i+DIMS_NUMB] - rc->bound[i]);
assert(vol >= 0.0);
return vol;
}
/**
* Precomputed volumes of the unit spheres for the first few dimensions
*/
const double UnitSphereVolumes[] = {
0.000000, /* dimension 0 */
2.000000, /* dimension 1 */
3.141593, /* dimension 2 */
4.188790, /* dimension 3 */
4.934802, /* dimension 4 */
5.263789, /* dimension 5 */
5.167713, /* dimension 6 */
4.724766, /* dimension 7 */
4.058712, /* dimension 8 */
3.298509, /* dimension 9 */
2.550164, /* dimension 10 */
1.884104, /* dimension 11 */
1.335263, /* dimension 12 */
0.910629, /* dimension 13 */
0.599265, /* dimension 14 */
0.381443, /* dimension 15 */
0.235331, /* dimension 16 */
0.140981, /* dimension 17 */
0.082146, /* dimension 18 */
0.046622, /* dimension 19 */
0.025807, /* dimension 20 */
};
#if DIMS_NUMB > 20
#error "not enough precomputed sphere volumes"
#endif
#define UnitSphereVolume UnitSphereVolumes[DIMS_NUMB]
/**
* Calculate the n-dimensional volume of the bounding sphere of a rectangle.
* The exact volume of the bounding sphere for the given RTREEMBR.
*/
REALTYPE RTreeRectSphericalVolume( RTREEMBR *rc )
{
int i;
double sum_of_squares=0, radius;
if (INVALID_RECT(rc))
return (REALTYPE) 0;
for (i=0; i<DIMS_NUMB; i++) {
double half_extent = (rc->bound[i+DIMS_NUMB] - rc->bound[i]) / 2;
sum_of_squares += half_extent * half_extent;
}
radius = sqrt(sum_of_squares);
return (REALTYPE)(pow(radius, DIMS_NUMB) * UnitSphereVolume);
}
/**
* Calculate the n-dimensional surface area of a rectangle
*/
REALTYPE RTreeRectSurfaceArea( RTREEMBR *rc )
{
int i, j;
REALTYPE sum = (REALTYPE) 0;
if (INVALID_RECT(rc))
return (REALTYPE) 0;
for (i=0; i<DIMS_NUMB; i++) {
REALTYPE face_area = (REALTYPE)1;
for (j=0; j<DIMS_NUMB; j++)
/* exclude i extent from product in this dimension */
if(i != j) {
REALTYPE j_extent = rc->bound[j+DIMS_NUMB] - rc->bound[j];
face_area *= j_extent;
}
sum += face_area;
}
return 2 * sum;
}
/**
* Combine two rectangles, make one that includes both.
*/
RTREEMBR RTreeCombineRect( RTREEMBR *rc1, RTREEMBR *rc2 )
{
int i, j;
RTREEMBR new_rect;
assert(rc1 && rc2);
if (INVALID_RECT(rc1))
return *rc2;
if (INVALID_RECT(rc2))
return *rc1;
for (i = 0; i < DIMS_NUMB; i++)
{
new_rect.bound[i] = MIN(rc1->bound[i], rc2->bound[i]);
j = i + DIMS_NUMB;
new_rect.bound[j] = MAX(rc1->bound[j], rc2->bound[j]);
}
return new_rect;
}
/**
* Decide whether two rectangles overlap.
*/
int RTreeOverlap( RTREEMBR *rc1, RTREEMBR *rc2)
{
int i, j;
assert(rc1 && rc2);
for (i=0; i<DIMS_NUMB; i++)
{
j = i + DIMS_NUMB; /* index for high sides */
if (rc1->bound[i] > rc2->bound[j] || rc2->bound[i] > rc1->bound[j])
return FALSE;
}
return TRUE;
}
/**
* Decide whether rectangle r is contained in rectangle s.
*/
int RTreeContained( RTREEMBR *r, RTREEMBR *s)
{
int i, j, result;
assert(r && s);
/* undefined mbr is contained in any other */
if (INVALID_RECT(r))
return TRUE;
/* no mbr (except an undefined one) is contained in an undef mbr */
if (INVALID_RECT(s))
return FALSE;
result = TRUE;
for (i = 0; i < DIMS_NUMB; i++)
{
j = i + DIMS_NUMB; /* index for high sides */
result = result && r->bound[i] >= s->bound[i] && r->bound[j] <= s->bound[j];
}
return result;
}
/**
* Split a node.
* Divides the nodes branches and the extra one between two nodes.
* Old node is one of the new ones, and one really new one is created.
* Tries more than one method for choosing a partition, uses best result.
*/
void RTreeSplitNode( RTREENODE *node, RTREEBRANCH *br, RTREENODE **new_node)
{
RTREEPARTITION *p;
int level;
assert(node && br);
/* load all the branches into a buffer, initialize old node */
level = node->level;
_RTreeGetBranches(node, br);
/* find partition */
p = &Partitions[0];
/* Note: can't use MINFILL(n) below since node was cleared by GetBranches() */
_RTreeMethodZero(p, level>0 ? MINNODEFILL : MINLEAFFILL);
/* put branches from buffer into 2 nodes according to chosen partition */
*new_node = RTreeNewNode();
(*new_node)->level = node->level = level;
_RTreeLoadNodes(node, *new_node, p);
assert(node->count+(*new_node)->count == p->total);
}
/**
* Initialize a RTREENODE structure.
*/
void RTreeInitNode( RTREENODE *node )
{
int i;
node->count = 0;
node->level = -1;
for (i = 0; i < MAXCARD; i++)
_RTreeInitBranch(&(node->branch[i]));
}
/**
* Make a new node and initialize to have all branch cells empty.
*/
RTREENODE *RTreeNewNode(void)
{
RTREENODE *node = (RTREENODE*) malloc(sizeof(RTREENODE));
assert(node);
RTreeInitNode(node);
return node;
}
void RTreeFreeNode( RTREENODE *node )
{
assert(node);
free(node);
}
/**
* Print out the data in a node.
*/
void RTreePrintNode( RTREENODE *node, int depth )
{
int i;
assert(node);
_RTreeTabIn(depth);
fprintf (stdout, "node");
if (node->level == 0)
fprintf (stdout, " LEAF");
else if (node->level > 0)
fprintf (stdout, " NONLEAF");
else
fprintf (stdout, " TYPE=?");
#pragma warning(push) /* C4311 */
#pragma warning( disable : 4311 )
fprintf (stdout, " level=%d count=%d address=%o ", node->level, node->count, (unsigned int) node);
#pragma warning(pop)
for (i=0; i<node->count; i++)
{
if(node->level == 0) {
/* _RTreeTabIn(depth); */
/* fprintf (stdout, " %d: data = %d ", i, n->branch[i].child); */
}
else {
_RTreeTabIn(depth);
fprintf (stdout, "branch %d ", i);
_RTreePrintBranch(&node->branch[i], depth+1);
}
}
}
/**
* Find the smallest rectangle that includes all rectangles in branches of a node.
*/
RTREEMBR RTreeNodeCover( RTREENODE *node )
{
int i, first_time=1;
RTREEMBR rc;
assert(node);
RTreeInitRect(&rc);
for (i = 0; i < MAXKIDS(node); i++)
{
if (node->branch[i].child)
{
if (first_time)
{
rc = node->branch[i].mbr;
first_time = 0;
}
else
rc = RTreeCombineRect(&rc, &(node->branch[i].mbr));
}
}
return rc;
}
/**
* Pick a branch. Pick the one that will need the smallest increase
* in area to accomodate the new rectangle. This will result in the
* least total area for the covering rectangles in the current node.
* In case of a tie, pick the one which was smaller before, to get
* the best resolution when searching.
*/
int RTreePickBranch( RTREEMBR *rc, RTREENODE *node)
{
RTREEMBR *r;
int i, first_time = 1;
REALTYPE increase, bestIncr=(REALTYPE)-1, area, bestArea=0;
int best=0;
RTREEMBR tmp_rect;
assert(rc && node);
for (i=0; i<MAXKIDS(node); i++)
{
if (node->branch[i].child)
{
r = &node->branch[i].mbr;
area = RTreeRectSphericalVolume(r);
tmp_rect = RTreeCombineRect(rc, r);
increase = RTreeRectSphericalVolume(&tmp_rect) - area;
if (increase < bestIncr || first_time)
{
best = i;
bestArea = area;
bestIncr = increase;
first_time = 0;
}
else if (increase == bestIncr && area < bestArea)
{
best = i;
bestArea = area;
bestIncr = increase;
}
}
}
return best;
}
/**
* Add a branch to a node. Split the node if necessary.
* Returns 0 if node not split. Old node updated.
* Returns 1 if node split, sets *new_node to address of new node.
* Old node updated, becomes one of two.
*/
int RTreeAddBranch( RTREEBRANCH *br, RTREENODE *node, RTREENODE **new_node)
{
int i;
assert(br && node);
if (node->count < MAXKIDS(node)) /* split won't be necessary */
{
for (i = 0; i < MAXKIDS(node); i++) /* find empty branch */
{
if (node->branch[i].child == NULL)
{
node->branch[i] = *br;
node->count++;
break;
}
}
return 0;
}
assert(new_node);
RTreeSplitNode(node, br, new_node);
return 1;
}
/**
* Disconnect a dependent node.
*/
void RTreeDisconnectBranch( RTREENODE *node, int i )
{
assert(node && i>=0 && i<MAXKIDS(node));
assert(node->branch[i].child);
_RTreeInitBranch(&(node->branch[i]));
node->count--;
}
/**
* Destroy (free) node recursively.
*/
void RTreeDestroyNode ( RTREENODE *node )
{
int i;
if (node->level > 0)
{
/* it is not leaf -> destroy childs */
for ( i = 0; i < NODECARD; i++)
{
if ( node->branch[i].child )
RTreeDestroyNode ( node->branch[i].child );
}
}
/* Free this node */
RTreeFreeNode( node );
}
/**
* Create a new rtree index, empty. Consists of a single node.
*/
RTREENODE * RTreeCreate(void)
{
RTREENODE * root = RTreeNewNode();
root->level = 0; /* leaf */
return root;
}
/**
* Destroy a rtree root must be a root of rtree. Free all memory.
*/
void RTreeDestroy(RTREENODE *root)
{
RTreeDestroyNode (root);
}
/**
* Search in an index tree or subtree for all data rectangles that overlap the argument rectangle.
* Return the number of qualifying data rects.
*/
int RTreeSearch( RTREENODE *node, RTREEMBR *rc, pfnSearchHitCallback pfnSHCB, void* pfnParam)
{
/* Fix not yet tested. */
int hitCount = 0;
int i;
assert(node && rc);
assert(node->level >= 0);
if (node->level > 0) /* this is an internal node in the tree */
{
for (i=0; i<NODECARD; i++){
if (node->branch[i].child && RTreeOverlap(rc, &node->branch[i].mbr))
hitCount += RTreeSearch(node->branch[i].child, rc, pfnSHCB, pfnParam);
}
}
else /* this is a leaf node */
{
#pragma warning(push) /* C4311 */
#pragma warning( disable : 4311 )
for (i=0; i<LEAFCARD; i++)
{
if (node->branch[i].child && RTreeOverlap(rc, &node->branch[i].mbr))
{
hitCount++;
/* call the user-provided callback and return if callback wants to terminate search early */
if(pfnSHCB && ! pfnSHCB((int)node->branch[i].child, pfnParam) )
return hitCount;
}
}
#pragma warning(pop)
}
return hitCount;
}
/**
* Insert a data rectangle into an index structure.
* RTreeInsertRect provides for splitting the root;
* returns 1 if root was split, 0 if it was not.
* The level argument specifies the number of steps up from the leaf
* level to insert; e.g. a data rectangle goes in at level = 0.
* _RTreeInsertRect does the recursion.
*/
int RTreeInsertRect( RTREEMBR *rc, int tid, RTREENODE **root, int level)
{
#ifdef _DEBUG
int i;
#endif
RTREENODE *newroot;
RTREENODE *newnode;
RTREEBRANCH b;
assert(rc && root);
assert(level >= 0 && level <= (*root)->level);
#ifdef _DEBUG
for (i=0; i<DIMS_NUMB; i++)
assert(rc->bound[i] <= rc->bound[DIMS_NUMB+i]);
#endif
/* root split */
if (_RTreeInsertRect(rc, tid, *root, &newnode, level))
{
newroot = RTreeNewNode(); /* grow a new root, & tree taller */
newroot->level = (*root)->level + 1;
b.mbr = RTreeNodeCover(*root);
b.child = *root;
RTreeAddBranch(&b, newroot, NULL);
b.mbr = RTreeNodeCover(newnode);
b.child = newnode;
RTreeAddBranch(&b, newroot, NULL);
*root = newroot;
return 1;
}
return 0;
}
/**
* Delete a data rectangle from an index structure.
* Pass in a pointer to a RTREEMBR, the tid of the record, ptr to ptr to root node.
* Returns 1 if record not found, 0 if success.
* RTreeDeleteRect provides for eliminating the root.
*/
int RTreeDeleteRect( RTREEMBR *rc, int tid, RTREENODE **root)
{
int i;
RTREENODE *tmp_nptr = NULL;
RTREELISTNODE *reInsertList = NULL;
RTREELISTNODE *e;
assert(rc && root);
assert(*root);
assert(tid >= 0);
if (!_RTreeDeleteRect(rc, tid, *root, &reInsertList))
{
/* found and deleted a data item */
/* reinsert any branches from eliminated nodes */
while (reInsertList)
{
tmp_nptr = reInsertList->node;
#pragma warning(push) /* C4311 */
#pragma warning( disable : 4311 )
for (i = 0; i < MAXKIDS(tmp_nptr); i++)
{
if (tmp_nptr->branch[i].child)
{
RTreeInsertRect(&(tmp_nptr->branch[i].mbr), (int)tmp_nptr->branch[i].child, root, tmp_nptr->level);
}
}
#pragma warning(pop)
e = reInsertList;
reInsertList = reInsertList->next;
RTreeFreeNode(e->node);
_RTreeFreeListNode(e);
}
/* check for redundant root (not leaf, 1 child) and eliminate */
if ((*root)->count == 1 && (*root)->level > 0)
{
for (i = 0; i < NODECARD; i++)
{
tmp_nptr = (*root)->branch[i].child;
if(tmp_nptr)
break;
}
assert(tmp_nptr);
RTreeFreeNode(*root);
*root = tmp_nptr;
}
return 0;
}
return 1;
}
測試檔案test.c：
/**
rtree lib usage example app.
*/
#include <stdio.h>
#include "rtree.h"
RTREEMBR rects[] = {
{ {0, 0, 0, 2, 2, 0} }, /* xmin, ymin, zmin, xmax, ymax, zmax (for 3 dimensional RTree) */
{ {5, 5, 0, 7, 7, 0} },
{ {8, 5, 0, 9, 6, 0} },
{ {7, 1, 0, 9, 2, 0} }
};
int nrects = sizeof(rects) / sizeof(rects[0]);
RTREEMBR search_rect = {
{6, 4, 0, 10, 6, 0} /* search will find above rects that this one overlaps */
};
int MySearchCallback(int id, void* arg)
{
/* Note: -1 to make up for the +1 when data was inserted */
fprintf (stdout, "Hit data mbr %d ", id-1);
return 1; /* keep going */
}
int main()
{
RTREENODE* root = RTreeCreate();
int i, nhits;
fprintf (stdout, "nrects = %d ", nrects);
/* Insert all the testing data rects */
for(i=0; i<nrects; i++){
RTreeInsertRect(&rects[i], /* the mbr being inserted */
i+10, /* i+1 is mbr ID. ID MUST NEVER BE ZERO */
&root, /* the address of rtree's root since root can change undernieth*/
0 /* always zero which means to add from the root */
);
}
nhits = RTreeSearch(root, &search_rect, MySearchCallback, 0);
fprintf (stdout, "Search resulted in %d hits ", nhits);
RTreeDestroy (root);
return 0;
}
rtree lib usage example app.
*/
#include <stdio.h>
#include "rtree.h"
RTREEMBR rects[] = {
{ {0, 0, 0, 2, 2, 0} }, /* xmin, ymin, zmin, xmax, ymax, zmax (for 3 dimensional RTree) */
{ {5, 5, 0, 7, 7, 0} },
{ {8, 5, 0, 9, 6, 0} },
{ {7, 1, 0, 9, 2, 0} }
};
int nrects = sizeof(rects) / sizeof(rects[0]);
RTREEMBR search_rect = {
{6, 4, 0, 10, 6, 0} /* search will find above rects that this one overlaps */
};
int MySearchCallback(int id, void* arg)
{
/* Note: -1 to make up for the +1 when data was inserted */
fprintf (stdout, "Hit data mbr %d ", id-1);
return 1; /* keep going */
}
int main()
{
RTREENODE* root = RTreeCreate();
int i, nhits;
fprintf (stdout, "nrects = %d ", nrects);
/* Insert all the testing data rects */
for(i=0; i<nrects; i++){
RTreeInsertRect(&rects[i], /* the mbr being inserted */
i+10, /* i+1 is mbr ID. ID MUST NEVER BE ZERO */
&root, /* the address of rtree's root since root can change undernieth*/
0 /* always zero which means to add from the root */
);
}
nhits = RTreeSearch(root, &search_rect, MySearchCallback, 0);
fprintf (stdout, "Search resulted in %d hits ", nhits);
RTreeDestroy (root);
return 0;
}
使用VS2005，新建一個Console專案test，選為空專案。然後把這3個檔案加入進來，就可以使用了。必要的話，把RTree.h和RTree.C建立成連線庫，就更方便了。
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