--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/persistentstorage/sqlite3api/SQLite/rtree.c Fri Jan 22 11:06:30 2010 +0200
@@ -0,0 +1,2854 @@
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code. In place of
+** a legal notice, here is a blessing:
+**
+** May you do good and not evil.
+** May you find forgiveness for yourself and forgive others.
+** May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains code for implementations of the r-tree and r*-tree
+** algorithms packaged as an SQLite virtual table module.
+**
+** $Id: rtree.c,v 1.9 2008/09/08 11:07:03 danielk1977 Exp $
+*/
+
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_RTREE)
+
+/*
+** This file contains an implementation of a couple of different variants
+** of the r-tree algorithm. See the README file for further details. The
+** same data-structure is used for all, but the algorithms for insert and
+** delete operations vary. The variants used are selected at compile time
+** by defining the following symbols:
+*/
+
+/* Either, both or none of the following may be set to activate
+** r*tree variant algorithms.
+*/
+#define VARIANT_RSTARTREE_CHOOSESUBTREE 0
+#define VARIANT_RSTARTREE_REINSERT 1
+
+/*
+** Exactly one of the following must be set to 1.
+*/
+#define VARIANT_GUTTMAN_QUADRATIC_SPLIT 0
+#define VARIANT_GUTTMAN_LINEAR_SPLIT 0
+#define VARIANT_RSTARTREE_SPLIT 1
+
+#define VARIANT_GUTTMAN_SPLIT \
+ (VARIANT_GUTTMAN_LINEAR_SPLIT||VARIANT_GUTTMAN_QUADRATIC_SPLIT)
+
+#if VARIANT_GUTTMAN_QUADRATIC_SPLIT
+ #define PickNext QuadraticPickNext
+ #define PickSeeds QuadraticPickSeeds
+ #define AssignCells splitNodeGuttman
+#endif
+#if VARIANT_GUTTMAN_LINEAR_SPLIT
+ #define PickNext LinearPickNext
+ #define PickSeeds LinearPickSeeds
+ #define AssignCells splitNodeGuttman
+#endif
+#if VARIANT_RSTARTREE_SPLIT
+ #define AssignCells splitNodeStartree
+#endif
+
+
+#ifndef SQLITE_CORE
+ #include "sqlite3ext.h"
+ SQLITE_EXTENSION_INIT1
+#else
+ #include "sqlite3.h"
+#endif
+
+#include <string.h>
+#include <assert.h>
+
+#ifndef SQLITE_AMALGAMATION
+typedef sqlite3_int64 i64;
+typedef unsigned char u8;
+typedef unsigned int u32;
+#endif
+
+typedef struct Rtree Rtree;
+typedef struct RtreeCursor RtreeCursor;
+typedef struct RtreeNode RtreeNode;
+typedef struct RtreeCell RtreeCell;
+typedef struct RtreeConstraint RtreeConstraint;
+typedef union RtreeCoord RtreeCoord;
+
+/* The rtree may have between 1 and RTREE_MAX_DIMENSIONS dimensions. */
+#define RTREE_MAX_DIMENSIONS 5
+
+/* Size of hash table Rtree.aHash. This hash table is not expected to
+** ever contain very many entries, so a fixed number of buckets is
+** used.
+*/
+#define HASHSIZE 128
+
+/*
+** An rtree virtual-table object.
+*/
+struct Rtree {
+ sqlite3_vtab base;
+ sqlite3 *db; /* Host database connection */
+ int iNodeSize; /* Size in bytes of each node in the node table */
+ int nDim; /* Number of dimensions */
+ int nBytesPerCell; /* Bytes consumed per cell */
+ int iDepth; /* Current depth of the r-tree structure */
+ char *zDb; /* Name of database containing r-tree table */
+ char *zName; /* Name of r-tree table */
+ RtreeNode *aHash[HASHSIZE]; /* Hash table of in-memory nodes. */
+ int nBusy; /* Current number of users of this structure */
+
+ /* List of nodes removed during a CondenseTree operation. List is
+ ** linked together via the pointer normally used for hash chains -
+ ** RtreeNode.pNext. RtreeNode.iNode stores the depth of the sub-tree
+ ** headed by the node (leaf nodes have RtreeNode.iNode==0).
+ */
+ RtreeNode *pDeleted;
+ int iReinsertHeight; /* Height of sub-trees Reinsert() has run on */
+
+ /* Statements to read/write/delete a record from xxx_node */
+ sqlite3_stmt *pReadNode;
+ sqlite3_stmt *pWriteNode;
+ sqlite3_stmt *pDeleteNode;
+
+ /* Statements to read/write/delete a record from xxx_rowid */
+ sqlite3_stmt *pReadRowid;
+ sqlite3_stmt *pWriteRowid;
+ sqlite3_stmt *pDeleteRowid;
+
+ /* Statements to read/write/delete a record from xxx_parent */
+ sqlite3_stmt *pReadParent;
+ sqlite3_stmt *pWriteParent;
+ sqlite3_stmt *pDeleteParent;
+
+ int eCoordType;
+};
+
+/* Possible values for eCoordType: */
+#define RTREE_COORD_REAL32 0
+#define RTREE_COORD_INT32 1
+
+/*
+** The minimum number of cells allowed for a node is a third of the
+** maximum. In Gutman's notation:
+**
+** m = M/3
+**
+** If an R*-tree "Reinsert" operation is required, the same number of
+** cells are removed from the overfull node and reinserted into the tree.
+*/
+#define RTREE_MINCELLS(p) ((((p)->iNodeSize-4)/(p)->nBytesPerCell)/3)
+#define RTREE_REINSERT(p) RTREE_MINCELLS(p)
+#define RTREE_MAXCELLS 51
+
+/*
+** An rtree cursor object.
+*/
+struct RtreeCursor {
+ sqlite3_vtab_cursor base;
+ RtreeNode *pNode; /* Node cursor is currently pointing at */
+ int iCell; /* Index of current cell in pNode */
+ int iStrategy; /* Copy of idxNum search parameter */
+ int nConstraint; /* Number of entries in aConstraint */
+ RtreeConstraint *aConstraint; /* Search constraints. */
+};
+
+union RtreeCoord {
+ float f;
+ int i;
+};
+
+/*
+** The argument is an RtreeCoord. Return the value stored within the RtreeCoord
+** formatted as a double. This macro assumes that local variable pRtree points
+** to the Rtree structure associated with the RtreeCoord.
+*/
+#define DCOORD(coord) ( \
+ (pRtree->eCoordType==RTREE_COORD_REAL32) ? \
+ ((double)coord.f) : \
+ ((double)coord.i) \
+)
+
+/*
+** A search constraint.
+*/
+struct RtreeConstraint {
+ int iCoord; /* Index of constrained coordinate */
+ int op; /* Constraining operation */
+ double rValue; /* Constraint value. */
+};
+
+/* Possible values for RtreeConstraint.op */
+#define RTREE_EQ 0x41
+#define RTREE_LE 0x42
+#define RTREE_LT 0x43
+#define RTREE_GE 0x44
+#define RTREE_GT 0x45
+
+/*
+** An rtree structure node.
+**
+** Data format (RtreeNode.zData):
+**
+** 1. If the node is the root node (node 1), then the first 2 bytes
+** of the node contain the tree depth as a big-endian integer.
+** For non-root nodes, the first 2 bytes are left unused.
+**
+** 2. The next 2 bytes contain the number of entries currently
+** stored in the node.
+**
+** 3. The remainder of the node contains the node entries. Each entry
+** consists of a single 8-byte integer followed by an even number
+** of 4-byte coordinates. For leaf nodes the integer is the rowid
+** of a record. For internal nodes it is the node number of a
+** child page.
+*/
+struct RtreeNode {
+ RtreeNode *pParent; /* Parent node */
+ i64 iNode;
+ int nRef;
+ int isDirty;
+ u8 *zData;
+ RtreeNode *pNext; /* Next node in this hash chain */
+};
+#define NCELL(pNode) readInt16(&(pNode)->zData[2])
+
+/*
+** Structure to store a deserialized rtree record.
+*/
+struct RtreeCell {
+ i64 iRowid;
+ RtreeCoord aCoord[RTREE_MAX_DIMENSIONS*2];
+};
+
+#define MAX(x,y) ((x) < (y) ? (y) : (x))
+#define MIN(x,y) ((x) > (y) ? (y) : (x))
+
+/*
+** Functions to deserialize a 16 bit integer, 32 bit real number and
+** 64 bit integer. The deserialized value is returned.
+*/
+static int readInt16(u8 *p){
+ return (p[0]<<8) + p[1];
+}
+static void readCoord(u8 *p, RtreeCoord *pCoord){
+ u32 i = (
+ (((u32)p[0]) << 24) +
+ (((u32)p[1]) << 16) +
+ (((u32)p[2]) << 8) +
+ (((u32)p[3]) << 0)
+ );
+ *(u32 *)pCoord = i;
+}
+static i64 readInt64(u8 *p){
+ return (
+ (((i64)p[0]) << 56) +
+ (((i64)p[1]) << 48) +
+ (((i64)p[2]) << 40) +
+ (((i64)p[3]) << 32) +
+ (((i64)p[4]) << 24) +
+ (((i64)p[5]) << 16) +
+ (((i64)p[6]) << 8) +
+ (((i64)p[7]) << 0)
+ );
+}
+
+/*
+** Functions to serialize a 16 bit integer, 32 bit real number and
+** 64 bit integer. The value returned is the number of bytes written
+** to the argument buffer (always 2, 4 and 8 respectively).
+*/
+static int writeInt16(u8 *p, int i){
+ p[0] = (i>> 8)&0xFF;
+ p[1] = (i>> 0)&0xFF;
+ return 2;
+}
+static int writeCoord(u8 *p, RtreeCoord *pCoord){
+ u32 i;
+ assert( sizeof(RtreeCoord)==4 );
+ assert( sizeof(u32)==4 );
+ i = *(u32 *)pCoord;
+ p[0] = (i>>24)&0xFF;
+ p[1] = (i>>16)&0xFF;
+ p[2] = (i>> 8)&0xFF;
+ p[3] = (i>> 0)&0xFF;
+ return 4;
+}
+static int writeInt64(u8 *p, i64 i){
+ p[0] = (i>>56)&0xFF;
+ p[1] = (i>>48)&0xFF;
+ p[2] = (i>>40)&0xFF;
+ p[3] = (i>>32)&0xFF;
+ p[4] = (i>>24)&0xFF;
+ p[5] = (i>>16)&0xFF;
+ p[6] = (i>> 8)&0xFF;
+ p[7] = (i>> 0)&0xFF;
+ return 8;
+}
+
+/*
+** Increment the reference count of node p.
+*/
+static void nodeReference(RtreeNode *p){
+ if( p ){
+ p->nRef++;
+ }
+}
+
+/*
+** Clear the content of node p (set all bytes to 0x00).
+*/
+static void nodeZero(Rtree *pRtree, RtreeNode *p){
+ if( p ){
+ memset(&p->zData[2], 0, pRtree->iNodeSize-2);
+ p->isDirty = 1;
+ }
+}
+
+/*
+** Given a node number iNode, return the corresponding key to use
+** in the Rtree.aHash table.
+*/
+static int nodeHash(i64 iNode){
+ return (
+ (iNode>>56) ^ (iNode>>48) ^ (iNode>>40) ^ (iNode>>32) ^
+ (iNode>>24) ^ (iNode>>16) ^ (iNode>> 8) ^ (iNode>> 0)
+ ) % HASHSIZE;
+}
+
+/*
+** Search the node hash table for node iNode. If found, return a pointer
+** to it. Otherwise, return 0.
+*/
+static RtreeNode *nodeHashLookup(Rtree *pRtree, i64 iNode){
+ RtreeNode *p;
+ assert( iNode!=0 );
+ for(p=pRtree->aHash[nodeHash(iNode)]; p && p->iNode!=iNode; p=p->pNext);
+ return p;
+}
+
+/*
+** Add node pNode to the node hash table.
+*/
+static void nodeHashInsert(Rtree *pRtree, RtreeNode *pNode){
+ if( pNode ){
+ int iHash;
+ assert( pNode->pNext==0 );
+ iHash = nodeHash(pNode->iNode);
+ pNode->pNext = pRtree->aHash[iHash];
+ pRtree->aHash[iHash] = pNode;
+ }
+}
+
+/*
+** Remove node pNode from the node hash table.
+*/
+static void nodeHashDelete(Rtree *pRtree, RtreeNode *pNode){
+ RtreeNode **pp;
+ if( pNode->iNode!=0 ){
+ pp = &pRtree->aHash[nodeHash(pNode->iNode)];
+ for( ; (*pp)!=pNode; pp = &(*pp)->pNext){ assert(*pp); }
+ *pp = pNode->pNext;
+ pNode->pNext = 0;
+ }
+}
+
+/*
+** Allocate and return new r-tree node. Initially, (RtreeNode.iNode==0),
+** indicating that node has not yet been assigned a node number. It is
+** assigned a node number when nodeWrite() is called to write the
+** node contents out to the database.
+*/
+static RtreeNode *nodeNew(Rtree *pRtree, RtreeNode *pParent, int zero){
+ RtreeNode *pNode;
+ pNode = (RtreeNode *)sqlite3_malloc(sizeof(RtreeNode) + pRtree->iNodeSize);
+ if( pNode ){
+ memset(pNode, 0, sizeof(RtreeNode) + (zero?pRtree->iNodeSize:0));
+ pNode->zData = (u8 *)&pNode[1];
+ pNode->nRef = 1;
+ pNode->pParent = pParent;
+ pNode->isDirty = 1;
+ nodeReference(pParent);
+ }
+ return pNode;
+}
+
+/*
+** Obtain a reference to an r-tree node.
+*/
+static int
+nodeAcquire(
+ Rtree *pRtree, /* R-tree structure */
+ i64 iNode, /* Node number to load */
+ RtreeNode *pParent, /* Either the parent node or NULL */
+ RtreeNode **ppNode /* OUT: Acquired node */
+){
+ int rc;
+ RtreeNode *pNode;
+
+ /* Check if the requested node is already in the hash table. If so,
+ ** increase its reference count and return it.
+ */
+ if( (pNode = nodeHashLookup(pRtree, iNode)) ){
+ assert( !pParent || !pNode->pParent || pNode->pParent==pParent );
+ if( pParent ){
+ pNode->pParent = pParent;
+ }
+ pNode->nRef++;
+ *ppNode = pNode;
+ return SQLITE_OK;
+ }
+
+ pNode = (RtreeNode *)sqlite3_malloc(sizeof(RtreeNode) + pRtree->iNodeSize);
+ if( !pNode ){
+ *ppNode = 0;
+ return SQLITE_NOMEM;
+ }
+ pNode->pParent = pParent;
+ pNode->zData = (u8 *)&pNode[1];
+ pNode->nRef = 1;
+ pNode->iNode = iNode;
+ pNode->isDirty = 0;
+ pNode->pNext = 0;
+
+ sqlite3_bind_int64(pRtree->pReadNode, 1, iNode);
+ rc = sqlite3_step(pRtree->pReadNode);
+ if( rc==SQLITE_ROW ){
+ const u8 *zBlob = sqlite3_column_blob(pRtree->pReadNode, 0);
+ memcpy(pNode->zData, zBlob, pRtree->iNodeSize);
+ nodeReference(pParent);
+ }else{
+ sqlite3_free(pNode);
+ pNode = 0;
+ }
+
+ *ppNode = pNode;
+ rc = sqlite3_reset(pRtree->pReadNode);
+
+ if( rc==SQLITE_OK && iNode==1 ){
+ pRtree->iDepth = readInt16(pNode->zData);
+ }
+
+ assert( (rc==SQLITE_OK && pNode) || (pNode==0 && rc!=SQLITE_OK) );
+ nodeHashInsert(pRtree, pNode);
+
+ return rc;
+}
+
+/*
+** Overwrite cell iCell of node pNode with the contents of pCell.
+*/
+static void nodeOverwriteCell(
+ Rtree *pRtree,
+ RtreeNode *pNode,
+ RtreeCell *pCell,
+ int iCell
+){
+ int ii;
+ u8 *p = &pNode->zData[4 + pRtree->nBytesPerCell*iCell];
+ p += writeInt64(p, pCell->iRowid);
+ for(ii=0; ii<(pRtree->nDim*2); ii++){
+ p += writeCoord(p, &pCell->aCoord[ii]);
+ }
+ pNode->isDirty = 1;
+}
+
+/*
+** Remove cell the cell with index iCell from node pNode.
+*/
+static void nodeDeleteCell(Rtree *pRtree, RtreeNode *pNode, int iCell){
+ u8 *pDst = &pNode->zData[4 + pRtree->nBytesPerCell*iCell];
+ u8 *pSrc = &pDst[pRtree->nBytesPerCell];
+ int nByte = (NCELL(pNode) - iCell - 1) * pRtree->nBytesPerCell;
+ memmove(pDst, pSrc, nByte);
+ writeInt16(&pNode->zData[2], NCELL(pNode)-1);
+ pNode->isDirty = 1;
+}
+
+/*
+** Insert the contents of cell pCell into node pNode. If the insert
+** is successful, return SQLITE_OK.
+**
+** If there is not enough free space in pNode, return SQLITE_FULL.
+*/
+static int
+nodeInsertCell(
+ Rtree *pRtree,
+ RtreeNode *pNode,
+ RtreeCell *pCell
+){
+ int nCell; /* Current number of cells in pNode */
+ int nMaxCell; /* Maximum number of cells for pNode */
+
+ nMaxCell = (pRtree->iNodeSize-4)/pRtree->nBytesPerCell;
+ nCell = NCELL(pNode);
+
+ assert(nCell<=nMaxCell);
+
+ if( nCell<nMaxCell ){
+ nodeOverwriteCell(pRtree, pNode, pCell, nCell);
+ writeInt16(&pNode->zData[2], nCell+1);
+ pNode->isDirty = 1;
+ }
+
+ return (nCell==nMaxCell);
+}
+
+/*
+** If the node is dirty, write it out to the database.
+*/
+static int
+nodeWrite(Rtree *pRtree, RtreeNode *pNode){
+ int rc = SQLITE_OK;
+ if( pNode->isDirty ){
+ sqlite3_stmt *p = pRtree->pWriteNode;
+ if( pNode->iNode ){
+ sqlite3_bind_int64(p, 1, pNode->iNode);
+ }else{
+ sqlite3_bind_null(p, 1);
+ }
+ sqlite3_bind_blob(p, 2, pNode->zData, pRtree->iNodeSize, SQLITE_STATIC);
+ sqlite3_step(p);
+ pNode->isDirty = 0;
+ rc = sqlite3_reset(p);
+ if( pNode->iNode==0 && rc==SQLITE_OK ){
+ pNode->iNode = sqlite3_last_insert_rowid(pRtree->db);
+ nodeHashInsert(pRtree, pNode);
+ }
+ }
+ return rc;
+}
+
+/*
+** Release a reference to a node. If the node is dirty and the reference
+** count drops to zero, the node data is written to the database.
+*/
+static int
+nodeRelease(Rtree *pRtree, RtreeNode *pNode){
+ int rc = SQLITE_OK;
+ if( pNode ){
+ assert( pNode->nRef>0 );
+ pNode->nRef--;
+ if( pNode->nRef==0 ){
+ if( pNode->iNode==1 ){
+ pRtree->iDepth = -1;
+ }
+ if( pNode->pParent ){
+ rc = nodeRelease(pRtree, pNode->pParent);
+ }
+ if( rc==SQLITE_OK ){
+ rc = nodeWrite(pRtree, pNode);
+ }
+ nodeHashDelete(pRtree, pNode);
+ sqlite3_free(pNode);
+ }
+ }
+ return rc;
+}
+
+/*
+** Return the 64-bit integer value associated with cell iCell of
+** node pNode. If pNode is a leaf node, this is a rowid. If it is
+** an internal node, then the 64-bit integer is a child page number.
+*/
+static i64 nodeGetRowid(
+ Rtree *pRtree,
+ RtreeNode *pNode,
+ int iCell
+){
+ assert( iCell<NCELL(pNode) );
+ return readInt64(&pNode->zData[4 + pRtree->nBytesPerCell*iCell]);
+}
+
+/*
+** Return coordinate iCoord from cell iCell in node pNode.
+*/
+static void nodeGetCoord(
+ Rtree *pRtree,
+ RtreeNode *pNode,
+ int iCell,
+ int iCoord,
+ RtreeCoord *pCoord /* Space to write result to */
+){
+ readCoord(&pNode->zData[12 + pRtree->nBytesPerCell*iCell + 4*iCoord], pCoord);
+}
+
+/*
+** Deserialize cell iCell of node pNode. Populate the structure pointed
+** to by pCell with the results.
+*/
+static void nodeGetCell(
+ Rtree *pRtree,
+ RtreeNode *pNode,
+ int iCell,
+ RtreeCell *pCell
+){
+ int ii;
+ pCell->iRowid = nodeGetRowid(pRtree, pNode, iCell);
+ for(ii=0; ii<pRtree->nDim*2; ii++){
+ nodeGetCoord(pRtree, pNode, iCell, ii, &pCell->aCoord[ii]);
+ }
+}
+
+
+/* Forward declaration for the function that does the work of
+** the virtual table module xCreate() and xConnect() methods.
+*/
+static int rtreeInit(
+ sqlite3 *, void *, int, const char *const*, sqlite3_vtab **, char **, int, int
+);
+
+/*
+** Rtree virtual table module xCreate method.
+*/
+static int rtreeCreate(
+ sqlite3 *db,
+ void *pAux,
+ int argc, const char *const*argv,
+ sqlite3_vtab **ppVtab,
+ char **pzErr
+){
+ return rtreeInit(db, pAux, argc, argv, ppVtab, pzErr, 1, (int)pAux);
+}
+
+/*
+** Rtree virtual table module xConnect method.
+*/
+static int rtreeConnect(
+ sqlite3 *db,
+ void *pAux,
+ int argc, const char *const*argv,
+ sqlite3_vtab **ppVtab,
+ char **pzErr
+){
+ return rtreeInit(db, pAux, argc, argv, ppVtab, pzErr, 0, (int)pAux);
+}
+
+/*
+** Increment the r-tree reference count.
+*/
+static void rtreeReference(Rtree *pRtree){
+ pRtree->nBusy++;
+}
+
+/*
+** Decrement the r-tree reference count. When the reference count reaches
+** zero the structure is deleted.
+*/
+static void rtreeRelease(Rtree *pRtree){
+ pRtree->nBusy--;
+ if( pRtree->nBusy==0 ){
+ sqlite3_finalize(pRtree->pReadNode);
+ sqlite3_finalize(pRtree->pWriteNode);
+ sqlite3_finalize(pRtree->pDeleteNode);
+ sqlite3_finalize(pRtree->pReadRowid);
+ sqlite3_finalize(pRtree->pWriteRowid);
+ sqlite3_finalize(pRtree->pDeleteRowid);
+ sqlite3_finalize(pRtree->pReadParent);
+ sqlite3_finalize(pRtree->pWriteParent);
+ sqlite3_finalize(pRtree->pDeleteParent);
+ sqlite3_free(pRtree);
+ }
+}
+
+/*
+** Rtree virtual table module xDisconnect method.
+*/
+static int rtreeDisconnect(sqlite3_vtab *pVtab){
+ rtreeRelease((Rtree *)pVtab);
+ return SQLITE_OK;
+}
+
+/*
+** Rtree virtual table module xDestroy method.
+*/
+static int rtreeDestroy(sqlite3_vtab *pVtab){
+ Rtree *pRtree = (Rtree *)pVtab;
+ int rc;
+ char *zCreate = sqlite3_mprintf(
+ "DROP TABLE '%q'.'%q_node';"
+ "DROP TABLE '%q'.'%q_rowid';"
+ "DROP TABLE '%q'.'%q_parent';",
+ pRtree->zDb, pRtree->zName,
+ pRtree->zDb, pRtree->zName,
+ pRtree->zDb, pRtree->zName
+ );
+ if( !zCreate ){
+ rc = SQLITE_NOMEM;
+ }else{
+ rc = sqlite3_exec(pRtree->db, zCreate, 0, 0, 0);
+ sqlite3_free(zCreate);
+ }
+ if( rc==SQLITE_OK ){
+ rtreeRelease(pRtree);
+ }
+
+ return rc;
+}
+
+/*
+** Rtree virtual table module xOpen method.
+*/
+static int rtreeOpen(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor){
+ int rc = SQLITE_NOMEM;
+ RtreeCursor *pCsr;
+
+ pCsr = (RtreeCursor *)sqlite3_malloc(sizeof(RtreeCursor));
+ if( pCsr ){
+ memset(pCsr, 0, sizeof(RtreeCursor));
+ pCsr->base.pVtab = pVTab;
+ rc = SQLITE_OK;
+ }
+ *ppCursor = (sqlite3_vtab_cursor *)pCsr;
+
+ return rc;
+}
+
+/*
+** Rtree virtual table module xClose method.
+*/
+static int rtreeClose(sqlite3_vtab_cursor *cur){
+ Rtree *pRtree = (Rtree *)(cur->pVtab);
+ int rc;
+ RtreeCursor *pCsr = (RtreeCursor *)cur;
+ sqlite3_free(pCsr->aConstraint);
+ rc = nodeRelease(pRtree, pCsr->pNode);
+ sqlite3_free(pCsr);
+ return rc;
+}
+
+/*
+** Rtree virtual table module xEof method.
+**
+** Return non-zero if the cursor does not currently point to a valid
+** record (i.e if the scan has finished), or zero otherwise.
+*/
+static int rtreeEof(sqlite3_vtab_cursor *cur){
+ RtreeCursor *pCsr = (RtreeCursor *)cur;
+ return (pCsr->pNode==0);
+}
+
+/*
+** Cursor pCursor currently points to a cell in a non-leaf page.
+** Return true if the sub-tree headed by the cell is filtered
+** (excluded) by the constraints in the pCursor->aConstraint[]
+** array, or false otherwise.
+*/
+static int testRtreeCell(Rtree *pRtree, RtreeCursor *pCursor){
+ RtreeCell cell;
+ int ii;
+ int bRes = 0;
+
+ nodeGetCell(pRtree, pCursor->pNode, pCursor->iCell, &cell);
+ for(ii=0; bRes==0 && ii<pCursor->nConstraint; ii++){
+ RtreeConstraint *p = &pCursor->aConstraint[ii];
+ double cell_min = DCOORD(cell.aCoord[(p->iCoord>>1)*2]);
+ double cell_max = DCOORD(cell.aCoord[(p->iCoord>>1)*2+1]);
+
+ assert(p->op==RTREE_LE || p->op==RTREE_LT || p->op==RTREE_GE
+ || p->op==RTREE_GT || p->op==RTREE_EQ
+ );
+
+ switch( p->op ){
+ case RTREE_LE: case RTREE_LT: bRes = p->rValue<cell_min; break;
+ case RTREE_GE: case RTREE_GT: bRes = p->rValue>cell_max; break;
+ case RTREE_EQ:
+ bRes = (p->rValue>cell_max || p->rValue<cell_min);
+ break;
+ }
+ }
+
+ return bRes;
+}
+
+/*
+** Return true if the cell that cursor pCursor currently points to
+** would be filtered (excluded) by the constraints in the
+** pCursor->aConstraint[] array, or false otherwise.
+**
+** This function assumes that the cell is part of a leaf node.
+*/
+static int testRtreeEntry(Rtree *pRtree, RtreeCursor *pCursor){
+ RtreeCell cell;
+ int ii;
+
+ nodeGetCell(pRtree, pCursor->pNode, pCursor->iCell, &cell);
+ for(ii=0; ii<pCursor->nConstraint; ii++){
+ RtreeConstraint *p = &pCursor->aConstraint[ii];
+ double coord = DCOORD(cell.aCoord[p->iCoord]);
+ int res;
+ assert(p->op==RTREE_LE || p->op==RTREE_LT || p->op==RTREE_GE
+ || p->op==RTREE_GT || p->op==RTREE_EQ
+ );
+ switch( p->op ){
+ case RTREE_LE: res = (coord<=p->rValue); break;
+ case RTREE_LT: res = (coord<p->rValue); break;
+ case RTREE_GE: res = (coord>=p->rValue); break;
+ case RTREE_GT: res = (coord>p->rValue); break;
+ case RTREE_EQ: res = (coord==p->rValue); break;
+ }
+
+ if( !res ) return 1;
+ }
+
+ return 0;
+}
+
+/*
+** Cursor pCursor currently points at a node that heads a sub-tree of
+** height iHeight (if iHeight==0, then the node is a leaf). Descend
+** to point to the left-most cell of the sub-tree that matches the
+** configured constraints.
+*/
+static int descendToCell(
+ Rtree *pRtree,
+ RtreeCursor *pCursor,
+ int iHeight,
+ int *pEof /* OUT: Set to true if cannot descend */
+){
+ int isEof;
+ int rc;
+ int ii;
+ RtreeNode *pChild;
+ sqlite3_int64 iRowid;
+
+ RtreeNode *pSavedNode = pCursor->pNode;
+ int iSavedCell = pCursor->iCell;
+
+ assert( iHeight>=0 );
+
+ if( iHeight==0 ){
+ isEof = testRtreeEntry(pRtree, pCursor);
+ }else{
+ isEof = testRtreeCell(pRtree, pCursor);
+ }
+ if( isEof || iHeight==0 ){
+ *pEof = isEof;
+ return SQLITE_OK;
+ }
+
+ iRowid = nodeGetRowid(pRtree, pCursor->pNode, pCursor->iCell);
+ rc = nodeAcquire(pRtree, iRowid, pCursor->pNode, &pChild);
+ if( rc!=SQLITE_OK ){
+ return rc;
+ }
+
+ nodeRelease(pRtree, pCursor->pNode);
+ pCursor->pNode = pChild;
+ isEof = 1;
+ for(ii=0; isEof && ii<NCELL(pChild); ii++){
+ pCursor->iCell = ii;
+ rc = descendToCell(pRtree, pCursor, iHeight-1, &isEof);
+ if( rc!=SQLITE_OK ){
+ return rc;
+ }
+ }
+
+ if( isEof ){
+ assert( pCursor->pNode==pChild );
+ nodeReference(pSavedNode);
+ nodeRelease(pRtree, pChild);
+ pCursor->pNode = pSavedNode;
+ pCursor->iCell = iSavedCell;
+ }
+
+ *pEof = isEof;
+ return SQLITE_OK;
+}
+
+/*
+** One of the cells in node pNode is guaranteed to have a 64-bit
+** integer value equal to iRowid. Return the index of this cell.
+*/
+static int nodeRowidIndex(Rtree *pRtree, RtreeNode *pNode, i64 iRowid){
+ int ii;
+ for(ii=0; nodeGetRowid(pRtree, pNode, ii)!=iRowid; ii++){
+ assert( ii<(NCELL(pNode)-1) );
+ }
+ return ii;
+}
+
+/*
+** Return the index of the cell containing a pointer to node pNode
+** in its parent. If pNode is the root node, return -1.
+*/
+static int nodeParentIndex(Rtree *pRtree, RtreeNode *pNode){
+ RtreeNode *pParent = pNode->pParent;
+ if( pParent ){
+ return nodeRowidIndex(pRtree, pParent, pNode->iNode);
+ }
+ return -1;
+}
+
+/*
+** Rtree virtual table module xNext method.
+*/
+static int rtreeNext(sqlite3_vtab_cursor *pVtabCursor){
+ Rtree *pRtree = (Rtree *)(pVtabCursor->pVtab);
+ RtreeCursor *pCsr = (RtreeCursor *)pVtabCursor;
+ int rc = SQLITE_OK;
+
+ if( pCsr->iStrategy==1 ){
+ /* This "scan" is a direct lookup by rowid. There is no next entry. */
+ nodeRelease(pRtree, pCsr->pNode);
+ pCsr->pNode = 0;
+ }
+
+ else if( pCsr->pNode ){
+ /* Move to the next entry that matches the configured constraints. */
+ int iHeight = 0;
+ while( pCsr->pNode ){
+ RtreeNode *pNode = pCsr->pNode;
+ int nCell = NCELL(pNode);
+ for(pCsr->iCell++; pCsr->iCell<nCell; pCsr->iCell++){
+ int isEof;
+ rc = descendToCell(pRtree, pCsr, iHeight, &isEof);
+ if( rc!=SQLITE_OK || !isEof ){
+ return rc;
+ }
+ }
+ pCsr->pNode = pNode->pParent;
+ pCsr->iCell = nodeParentIndex(pRtree, pNode);
+ nodeReference(pCsr->pNode);
+ nodeRelease(pRtree, pNode);
+ iHeight++;
+ }
+ }
+
+ return rc;
+}
+
+/*
+** Rtree virtual table module xRowid method.
+*/
+static int rtreeRowid(sqlite3_vtab_cursor *pVtabCursor, sqlite_int64 *pRowid){
+ Rtree *pRtree = (Rtree *)pVtabCursor->pVtab;
+ RtreeCursor *pCsr = (RtreeCursor *)pVtabCursor;
+
+ assert(pCsr->pNode);
+ *pRowid = nodeGetRowid(pRtree, pCsr->pNode, pCsr->iCell);
+
+ return SQLITE_OK;
+}
+
+/*
+** Rtree virtual table module xColumn method.
+*/
+static int rtreeColumn(sqlite3_vtab_cursor *cur, sqlite3_context *ctx, int i){
+ Rtree *pRtree = (Rtree *)cur->pVtab;
+ RtreeCursor *pCsr = (RtreeCursor *)cur;
+
+ if( i==0 ){
+ i64 iRowid = nodeGetRowid(pRtree, pCsr->pNode, pCsr->iCell);
+ sqlite3_result_int64(ctx, iRowid);
+ }else{
+ RtreeCoord c;
+ nodeGetCoord(pRtree, pCsr->pNode, pCsr->iCell, i-1, &c);
+ if( pRtree->eCoordType==RTREE_COORD_REAL32 ){
+ sqlite3_result_double(ctx, c.f);
+ }else{
+ assert( pRtree->eCoordType==RTREE_COORD_INT32 );
+ sqlite3_result_int(ctx, c.i);
+ }
+ }
+
+ return SQLITE_OK;
+}
+
+/*
+** Use nodeAcquire() to obtain the leaf node containing the record with
+** rowid iRowid. If successful, set *ppLeaf to point to the node and
+** return SQLITE_OK. If there is no such record in the table, set
+** *ppLeaf to 0 and return SQLITE_OK. If an error occurs, set *ppLeaf
+** to zero and return an SQLite error code.
+*/
+static int findLeafNode(Rtree *pRtree, i64 iRowid, RtreeNode **ppLeaf){
+ int rc;
+ *ppLeaf = 0;
+ sqlite3_bind_int64(pRtree->pReadRowid, 1, iRowid);
+ if( sqlite3_step(pRtree->pReadRowid)==SQLITE_ROW ){
+ i64 iNode = sqlite3_column_int64(pRtree->pReadRowid, 0);
+ rc = nodeAcquire(pRtree, iNode, 0, ppLeaf);
+ sqlite3_reset(pRtree->pReadRowid);
+ }else{
+ rc = sqlite3_reset(pRtree->pReadRowid);
+ }
+ return rc;
+}
+
+
+/*
+** Rtree virtual table module xFilter method.
+*/
+static int rtreeFilter(
+ sqlite3_vtab_cursor *pVtabCursor,
+ int idxNum, const char *idxStr,
+ int argc, sqlite3_value **argv
+){
+ Rtree *pRtree = (Rtree *)pVtabCursor->pVtab;
+ RtreeCursor *pCsr = (RtreeCursor *)pVtabCursor;
+
+ RtreeNode *pRoot = 0;
+ int ii;
+ int rc = SQLITE_OK;
+
+ rtreeReference(pRtree);
+
+ sqlite3_free(pCsr->aConstraint);
+ pCsr->aConstraint = 0;
+ pCsr->iStrategy = idxNum;
+
+ if( idxNum==1 ){
+ /* Special case - lookup by rowid. */
+ RtreeNode *pLeaf; /* Leaf on which the required cell resides */
+ i64 iRowid = sqlite3_value_int64(argv[0]);
+ rc = findLeafNode(pRtree, iRowid, &pLeaf);
+ pCsr->pNode = pLeaf;
+ if( pLeaf && rc==SQLITE_OK ){
+ pCsr->iCell = nodeRowidIndex(pRtree, pLeaf, iRowid);
+ }
+ }else{
+ /* Normal case - r-tree scan. Set up the RtreeCursor.aConstraint array
+ ** with the configured constraints.
+ */
+ if( argc>0 ){
+ pCsr->aConstraint = sqlite3_malloc(sizeof(RtreeConstraint)*argc);
+ pCsr->nConstraint = argc;
+ if( !pCsr->aConstraint ){
+ rc = SQLITE_NOMEM;
+ }else{
+ assert( (idxStr==0 && argc==0) || strlen(idxStr)==argc*2 );
+ for(ii=0; ii<argc; ii++){
+ RtreeConstraint *p = &pCsr->aConstraint[ii];
+ p->op = idxStr[ii*2];
+ p->iCoord = idxStr[ii*2+1]-'a';
+ p->rValue = sqlite3_value_double(argv[ii]);
+ }
+ }
+ }
+
+ if( rc==SQLITE_OK ){
+ pCsr->pNode = 0;
+ rc = nodeAcquire(pRtree, 1, 0, &pRoot);
+ }
+ if( rc==SQLITE_OK ){
+ int isEof = 1;
+ int nCell = NCELL(pRoot);
+ pCsr->pNode = pRoot;
+ for(pCsr->iCell=0; rc==SQLITE_OK && pCsr->iCell<nCell; pCsr->iCell++){
+ assert( pCsr->pNode==pRoot );
+ rc = descendToCell(pRtree, pCsr, pRtree->iDepth, &isEof);
+ if( !isEof ){
+ break;
+ }
+ }
+ if( rc==SQLITE_OK && isEof ){
+ assert( pCsr->pNode==pRoot );
+ nodeRelease(pRtree, pRoot);
+ pCsr->pNode = 0;
+ }
+ assert( rc!=SQLITE_OK || !pCsr->pNode || pCsr->iCell<NCELL(pCsr->pNode) );
+ }
+ }
+
+ rtreeRelease(pRtree);
+ return rc;
+}
+
+/*
+** Rtree virtual table module xBestIndex method. There are three
+** table scan strategies to choose from (in order from most to
+** least desirable):
+**
+** idxNum idxStr Strategy
+** ------------------------------------------------
+** 1 Unused Direct lookup by rowid.
+** 2 See below R-tree query.
+** 3 Unused Full table scan.
+** ------------------------------------------------
+**
+** If strategy 1 or 3 is used, then idxStr is not meaningful. If strategy
+** 2 is used, idxStr is formatted to contain 2 bytes for each
+** constraint used. The first two bytes of idxStr correspond to
+** the constraint in sqlite3_index_info.aConstraintUsage[] with
+** (argvIndex==1) etc.
+**
+** The first of each pair of bytes in idxStr identifies the constraint
+** operator as follows:
+**
+** Operator Byte Value
+** ----------------------
+** = 0x41 ('A')
+** <= 0x42 ('B')
+** < 0x43 ('C')
+** >= 0x44 ('D')
+** > 0x45 ('E')
+** ----------------------
+**
+** The second of each pair of bytes identifies the coordinate column
+** to which the constraint applies. The leftmost coordinate column
+** is 'a', the second from the left 'b' etc.
+*/
+static int rtreeBestIndex(sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo){
+ int rc = SQLITE_OK;
+ int ii, cCol;
+
+ int iIdx = 0;
+ char zIdxStr[RTREE_MAX_DIMENSIONS*8+1];
+ memset(zIdxStr, 0, sizeof(zIdxStr));
+
+ assert( pIdxInfo->idxStr==0 );
+ for(ii=0; ii<pIdxInfo->nConstraint; ii++){
+ struct sqlite3_index_constraint *p = &pIdxInfo->aConstraint[ii];
+
+ if( p->usable && p->iColumn==0 && p->op==SQLITE_INDEX_CONSTRAINT_EQ ){
+ /* We have an equality constraint on the rowid. Use strategy 1. */
+ int jj;
+ for(jj=0; jj<ii; jj++){
+ pIdxInfo->aConstraintUsage[jj].argvIndex = 0;
+ pIdxInfo->aConstraintUsage[jj].omit = 0;
+ }
+ pIdxInfo->idxNum = 1;
+ pIdxInfo->aConstraintUsage[ii].argvIndex = 1;
+ pIdxInfo->aConstraintUsage[jj].omit = 1;
+
+ /* This strategy involves a two rowid lookups on an B-Tree structures
+ ** and then a linear search of an R-Tree node. This should be
+ ** considered almost as quick as a direct rowid lookup (for which
+ ** sqlite uses an internal cost of 0.0).
+ */
+ pIdxInfo->estimatedCost = 10.0;
+ return SQLITE_OK;
+ }
+
+ if( p->usable && p->iColumn>0 ){
+ u8 op = 0;
+ switch( p->op ){
+ case SQLITE_INDEX_CONSTRAINT_EQ: op = RTREE_EQ; break;
+ case SQLITE_INDEX_CONSTRAINT_GT: op = RTREE_GT; break;
+ case SQLITE_INDEX_CONSTRAINT_LE: op = RTREE_LE; break;
+ case SQLITE_INDEX_CONSTRAINT_LT: op = RTREE_LT; break;
+ case SQLITE_INDEX_CONSTRAINT_GE: op = RTREE_GE; break;
+ }
+ if( op ){
+ /* Make sure this particular constraint has not been used before.
+ ** If it has been used before, ignore it.
+ **
+ ** A <= or < can be used if there is a prior >= or >.
+ ** A >= or > can be used if there is a prior < or <=.
+ ** A <= or < is disqualified if there is a prior <=, <, or ==.
+ ** A >= or > is disqualified if there is a prior >=, >, or ==.
+ ** A == is disqualifed if there is any prior constraint.
+ */
+ int j, opmsk;
+ static const unsigned char compatible[] = { 0, 0, 1, 1, 2, 2 };
+ assert( compatible[RTREE_EQ & 7]==0 );
+ assert( compatible[RTREE_LT & 7]==1 );
+ assert( compatible[RTREE_LE & 7]==1 );
+ assert( compatible[RTREE_GT & 7]==2 );
+ assert( compatible[RTREE_GE & 7]==2 );
+ cCol = p->iColumn - 1 + 'a';
+ opmsk = compatible[op & 7];
+ for(j=0; j<iIdx; j+=2){
+ if( zIdxStr[j+1]==cCol && (compatible[zIdxStr[j] & 7] & opmsk)!=0 ){
+ op = 0;
+ break;
+ }
+ }
+ }
+ if( op ){
+ assert( iIdx<sizeof(zIdxStr)-1 );
+ zIdxStr[iIdx++] = op;
+ zIdxStr[iIdx++] = cCol;
+ pIdxInfo->aConstraintUsage[ii].argvIndex = (iIdx/2);
+ pIdxInfo->aConstraintUsage[ii].omit = 1;
+ }
+ }
+ }
+
+ pIdxInfo->idxNum = 2;
+ pIdxInfo->needToFreeIdxStr = 1;
+ if( iIdx>0 && 0==(pIdxInfo->idxStr = sqlite3_mprintf("%s", zIdxStr)) ){
+ return SQLITE_NOMEM;
+ }
+ assert( iIdx>=0 );
+ pIdxInfo->estimatedCost = (2000000.0 / (double)(iIdx + 1));
+ return rc;
+}
+
+/*
+** Return the N-dimensional volumn of the cell stored in *p.
+*/
+static float cellArea(Rtree *pRtree, RtreeCell *p){
+ float area = 1.0;
+ int ii;
+ for(ii=0; ii<(pRtree->nDim*2); ii+=2){
+ area = area * (DCOORD(p->aCoord[ii+1]) - DCOORD(p->aCoord[ii]));
+ }
+ return area;
+}
+
+/*
+** Return the margin length of cell p. The margin length is the sum
+** of the objects size in each dimension.
+*/
+static float cellMargin(Rtree *pRtree, RtreeCell *p){
+ float margin = 0.0;
+ int ii;
+ for(ii=0; ii<(pRtree->nDim*2); ii+=2){
+ margin += (DCOORD(p->aCoord[ii+1]) - DCOORD(p->aCoord[ii]));
+ }
+ return margin;
+}
+
+/*
+** Store the union of cells p1 and p2 in p1.
+*/
+static void cellUnion(Rtree *pRtree, RtreeCell *p1, RtreeCell *p2){
+ int ii;
+ if( pRtree->eCoordType==RTREE_COORD_REAL32 ){
+ for(ii=0; ii<(pRtree->nDim*2); ii+=2){
+ p1->aCoord[ii].f = MIN(p1->aCoord[ii].f, p2->aCoord[ii].f);
+ p1->aCoord[ii+1].f = MAX(p1->aCoord[ii+1].f, p2->aCoord[ii+1].f);
+ }
+ }else{
+ for(ii=0; ii<(pRtree->nDim*2); ii+=2){
+ p1->aCoord[ii].i = MIN(p1->aCoord[ii].i, p2->aCoord[ii].i);
+ p1->aCoord[ii+1].i = MAX(p1->aCoord[ii+1].i, p2->aCoord[ii+1].i);
+ }
+ }
+}
+
+/*
+** Return true if the area covered by p2 is a subset of the area covered
+** by p1. False otherwise.
+*/
+static int cellContains(Rtree *pRtree, RtreeCell *p1, RtreeCell *p2){
+ int ii;
+ int isInt = (pRtree->eCoordType==RTREE_COORD_INT32);
+ for(ii=0; ii<(pRtree->nDim*2); ii+=2){
+ RtreeCoord *a1 = &p1->aCoord[ii];
+ RtreeCoord *a2 = &p2->aCoord[ii];
+ if( (!isInt && (a2[0].f<a1[0].f || a2[1].f>a1[1].f))
+ || ( isInt && (a2[0].i<a1[0].i || a2[1].i>a1[1].i))
+ ){
+ return 0;
+ }
+ }
+ return 1;
+}
+
+/*
+** Return the amount cell p would grow by if it were unioned with pCell.
+*/
+static float cellGrowth(Rtree *pRtree, RtreeCell *p, RtreeCell *pCell){
+ float area;
+ RtreeCell cell;
+ memcpy(&cell, p, sizeof(RtreeCell));
+ area = cellArea(pRtree, &cell);
+ cellUnion(pRtree, &cell, pCell);
+ return (cellArea(pRtree, &cell)-area);
+}
+
+#if VARIANT_RSTARTREE_CHOOSESUBTREE || VARIANT_RSTARTREE_SPLIT
+static float cellOverlap(
+ Rtree *pRtree,
+ RtreeCell *p,
+ RtreeCell *aCell,
+ int nCell,
+ int iExclude
+){
+ int ii;
+ float overlap = 0.0;
+ for(ii=0; ii<nCell; ii++){
+ if( ii!=iExclude ){
+ int jj;
+ float o = 1.0;
+ for(jj=0; jj<(pRtree->nDim*2); jj+=2){
+ double x1;
+ double x2;
+
+ x1 = MAX(DCOORD(p->aCoord[jj]), DCOORD(aCell[ii].aCoord[jj]));
+ x2 = MIN(DCOORD(p->aCoord[jj+1]), DCOORD(aCell[ii].aCoord[jj+1]));
+
+ if( x2<x1 ){
+ o = 0.0;
+ break;
+ }else{
+ o = o * (x2-x1);
+ }
+ }
+ overlap += o;
+ }
+ }
+ return overlap;
+}
+#endif
+
+#if VARIANT_RSTARTREE_CHOOSESUBTREE
+static float cellOverlapEnlargement(
+ Rtree *pRtree,
+ RtreeCell *p,
+ RtreeCell *pInsert,
+ RtreeCell *aCell,
+ int nCell,
+ int iExclude
+){
+ float before;
+ float after;
+ before = cellOverlap(pRtree, p, aCell, nCell, iExclude);
+ cellUnion(pRtree, p, pInsert);
+ after = cellOverlap(pRtree, p, aCell, nCell, iExclude);
+ return after-before;
+}
+#endif
+
+
+/*
+** This function implements the ChooseLeaf algorithm from Gutman[84].
+** ChooseSubTree in r*tree terminology.
+*/
+static int ChooseLeaf(
+ Rtree *pRtree, /* Rtree table */
+ RtreeCell *pCell, /* Cell to insert into rtree */
+ int iHeight, /* Height of sub-tree rooted at pCell */
+ RtreeNode **ppLeaf /* OUT: Selected leaf page */
+){
+ int rc;
+ int ii;
+ RtreeNode *pNode;
+ rc = nodeAcquire(pRtree, 1, 0, &pNode);
+
+ for(ii=0; rc==SQLITE_OK && ii<(pRtree->iDepth-iHeight); ii++){
+ int iCell;
+ sqlite3_int64 iBest;
+
+ float fMinGrowth;
+ float fMinArea;
+ float fMinOverlap;
+
+ int nCell = NCELL(pNode);
+ RtreeCell cell;
+ RtreeNode *pChild;
+
+ RtreeCell *aCell = 0;
+
+#if VARIANT_RSTARTREE_CHOOSESUBTREE
+ if( ii==(pRtree->iDepth-1) ){
+ int jj;
+ aCell = sqlite3_malloc(sizeof(RtreeCell)*nCell);
+ if( !aCell ){
+ rc = SQLITE_NOMEM;
+ nodeRelease(pRtree, pNode);
+ pNode = 0;
+ continue;
+ }
+ for(jj=0; jj<nCell; jj++){
+ nodeGetCell(pRtree, pNode, jj, &aCell[jj]);
+ }
+ }
+#endif
+
+ /* Select the child node which will be enlarged the least if pCell
+ ** is inserted into it. Resolve ties by choosing the entry with
+ ** the smallest area.
+ */
+ for(iCell=0; iCell<nCell; iCell++){
+ float growth;
+ float area;
+ float overlap = 0.0;
+ nodeGetCell(pRtree, pNode, iCell, &cell);
+ growth = cellGrowth(pRtree, &cell, pCell);
+ area = cellArea(pRtree, &cell);
+#if VARIANT_RSTARTREE_CHOOSESUBTREE
+ if( ii==(pRtree->iDepth-1) ){
+ overlap = cellOverlapEnlargement(pRtree,&cell,pCell,aCell,nCell,iCell);
+ }
+#endif
+ if( (iCell==0)
+ || (overlap<fMinOverlap)
+ || (overlap==fMinOverlap && growth<fMinGrowth)
+ || (overlap==fMinOverlap && growth==fMinGrowth && area<fMinArea)
+ ){
+ fMinOverlap = overlap;
+ fMinGrowth = growth;
+ fMinArea = area;
+ iBest = cell.iRowid;
+ }
+ }
+
+ sqlite3_free(aCell);
+ rc = nodeAcquire(pRtree, iBest, pNode, &pChild);
+ nodeRelease(pRtree, pNode);
+ pNode = pChild;
+ }
+
+ *ppLeaf = pNode;
+ return rc;
+}
+
+/*
+** A cell with the same content as pCell has just been inserted into
+** the node pNode. This function updates the bounding box cells in
+** all ancestor elements.
+*/
+static void AdjustTree(
+ Rtree *pRtree, /* Rtree table */
+ RtreeNode *pNode, /* Adjust ancestry of this node. */
+ RtreeCell *pCell /* This cell was just inserted */
+){
+ RtreeNode *p = pNode;
+ while( p->pParent ){
+ RtreeCell cell;
+ RtreeNode *pParent = p->pParent;
+ int iCell = nodeParentIndex(pRtree, p);
+
+ nodeGetCell(pRtree, pParent, iCell, &cell);
+ if( !cellContains(pRtree, &cell, pCell) ){
+ cellUnion(pRtree, &cell, pCell);
+ nodeOverwriteCell(pRtree, pParent, &cell, iCell);
+ }
+
+ p = pParent;
+ }
+}
+
+/*
+** Write mapping (iRowid->iNode) to the <rtree>_rowid table.
+*/
+static int rowidWrite(Rtree *pRtree, sqlite3_int64 iRowid, sqlite3_int64 iNode){
+ sqlite3_bind_int64(pRtree->pWriteRowid, 1, iRowid);
+ sqlite3_bind_int64(pRtree->pWriteRowid, 2, iNode);
+ sqlite3_step(pRtree->pWriteRowid);
+ return sqlite3_reset(pRtree->pWriteRowid);
+}
+
+/*
+** Write mapping (iNode->iPar) to the <rtree>_parent table.
+*/
+static int parentWrite(Rtree *pRtree, sqlite3_int64 iNode, sqlite3_int64 iPar){
+ sqlite3_bind_int64(pRtree->pWriteParent, 1, iNode);
+ sqlite3_bind_int64(pRtree->pWriteParent, 2, iPar);
+ sqlite3_step(pRtree->pWriteParent);
+ return sqlite3_reset(pRtree->pWriteParent);
+}
+
+static int rtreeInsertCell(Rtree *, RtreeNode *, RtreeCell *, int);
+
+#if VARIANT_GUTTMAN_LINEAR_SPLIT
+/*
+** Implementation of the linear variant of the PickNext() function from
+** Guttman[84].
+*/
+static RtreeCell *LinearPickNext(
+ Rtree *pRtree,
+ RtreeCell *aCell,
+ int nCell,
+ RtreeCell *pLeftBox,
+ RtreeCell *pRightBox,
+ int *aiUsed
+){
+ int ii;
+ for(ii=0; aiUsed[ii]; ii++);
+ aiUsed[ii] = 1;
+ return &aCell[ii];
+}
+
+/*
+** Implementation of the linear variant of the PickSeeds() function from
+** Guttman[84].
+*/
+static void LinearPickSeeds(
+ Rtree *pRtree,
+ RtreeCell *aCell,
+ int nCell,
+ int *piLeftSeed,
+ int *piRightSeed
+){
+ int i;
+ int iLeftSeed = 0;
+ int iRightSeed = 1;
+ float maxNormalInnerWidth = 0.0;
+
+ /* Pick two "seed" cells from the array of cells. The algorithm used
+ ** here is the LinearPickSeeds algorithm from Gutman[1984]. The
+ ** indices of the two seed cells in the array are stored in local
+ ** variables iLeftSeek and iRightSeed.
+ */
+ for(i=0; i<pRtree->nDim; i++){
+ float x1 = aCell[0].aCoord[i*2];
+ float x2 = aCell[0].aCoord[i*2+1];
+ float x3 = x1;
+ float x4 = x2;
+ int jj;
+
+ int iCellLeft = 0;
+ int iCellRight = 0;
+
+ for(jj=1; jj<nCell; jj++){
+ float left = aCell[jj].aCoord[i*2];
+ float right = aCell[jj].aCoord[i*2+1];
+
+ if( left<x1 ) x1 = left;
+ if( right>x4 ) x4 = right;
+ if( left>x3 ){
+ x3 = left;
+ iCellRight = jj;
+ }
+ if( right<x2 ){
+ x2 = right;
+ iCellLeft = jj;
+ }
+ }
+
+ if( x4!=x1 ){
+ float normalwidth = (x3 - x2) / (x4 - x1);
+ if( normalwidth>maxNormalInnerWidth ){
+ iLeftSeed = iCellLeft;
+ iRightSeed = iCellRight;
+ }
+ }
+ }
+
+ *piLeftSeed = iLeftSeed;
+ *piRightSeed = iRightSeed;
+}
+#endif /* VARIANT_GUTTMAN_LINEAR_SPLIT */
+
+#if VARIANT_GUTTMAN_QUADRATIC_SPLIT
+/*
+** Implementation of the quadratic variant of the PickNext() function from
+** Guttman[84].
+*/
+static RtreeCell *QuadraticPickNext(
+ Rtree *pRtree,
+ RtreeCell *aCell,
+ int nCell,
+ RtreeCell *pLeftBox,
+ RtreeCell *pRightBox,
+ int *aiUsed
+){
+ #define FABS(a) ((a)<0.0?-1.0*(a):(a))
+
+ int iSelect = -1;
+ float fDiff;
+ int ii;
+ for(ii=0; ii<nCell; ii++){
+ if( aiUsed[ii]==0 ){
+ float left = cellGrowth(pRtree, pLeftBox, &aCell[ii]);
+ float right = cellGrowth(pRtree, pLeftBox, &aCell[ii]);
+ float diff = FABS(right-left);
+ if( iSelect<0 || diff>fDiff ){
+ fDiff = diff;
+ iSelect = ii;
+ }
+ }
+ }
+ aiUsed[iSelect] = 1;
+ return &aCell[iSelect];
+}
+
+/*
+** Implementation of the quadratic variant of the PickSeeds() function from
+** Guttman[84].
+*/
+static void QuadraticPickSeeds(
+ Rtree *pRtree,
+ RtreeCell *aCell,
+ int nCell,
+ int *piLeftSeed,
+ int *piRightSeed
+){
+ int ii;
+ int jj;
+
+ int iLeftSeed = 0;
+ int iRightSeed = 1;
+ float fWaste = 0.0;
+
+ for(ii=0; ii<nCell; ii++){
+ for(jj=ii+1; jj<nCell; jj++){
+ float right = cellArea(pRtree, &aCell[jj]);
+ float growth = cellGrowth(pRtree, &aCell[ii], &aCell[jj]);
+ float waste = growth - right;
+
+ if( waste>fWaste ){
+ iLeftSeed = ii;
+ iRightSeed = jj;
+ fWaste = waste;
+ }
+ }
+ }
+
+ *piLeftSeed = iLeftSeed;
+ *piRightSeed = iRightSeed;
+}
+#endif /* VARIANT_GUTTMAN_QUADRATIC_SPLIT */
+
+/*
+** Arguments aIdx, aDistance and aSpare all point to arrays of size
+** nIdx. The aIdx array contains the set of integers from 0 to
+** (nIdx-1) in no particular order. This function sorts the values
+** in aIdx according to the indexed values in aDistance. For
+** example, assuming the inputs:
+**
+** aIdx = { 0, 1, 2, 3 }
+** aDistance = { 5.0, 2.0, 7.0, 6.0 }
+**
+** this function sets the aIdx array to contain:
+**
+** aIdx = { 0, 1, 2, 3 }
+**
+** The aSpare array is used as temporary working space by the
+** sorting algorithm.
+*/
+static void SortByDistance(
+ int *aIdx,
+ int nIdx,
+ float *aDistance,
+ int *aSpare
+){
+ if( nIdx>1 ){
+ int iLeft = 0;
+ int iRight = 0;
+
+ int nLeft = nIdx/2;
+ int nRight = nIdx-nLeft;
+ int *aLeft = aIdx;
+ int *aRight = &aIdx[nLeft];
+
+ SortByDistance(aLeft, nLeft, aDistance, aSpare);
+ SortByDistance(aRight, nRight, aDistance, aSpare);
+
+ memcpy(aSpare, aLeft, sizeof(int)*nLeft);
+ aLeft = aSpare;
+
+ while( iLeft<nLeft || iRight<nRight ){
+ if( iLeft==nLeft ){
+ aIdx[iLeft+iRight] = aRight[iRight];
+ iRight++;
+ }else if( iRight==nRight ){
+ aIdx[iLeft+iRight] = aLeft[iLeft];
+ iLeft++;
+ }else{
+ float fLeft = aDistance[aLeft[iLeft]];
+ float fRight = aDistance[aRight[iRight]];
+ if( fLeft<fRight ){
+ aIdx[iLeft+iRight] = aLeft[iLeft];
+ iLeft++;
+ }else{
+ aIdx[iLeft+iRight] = aRight[iRight];
+ iRight++;
+ }
+ }
+ }
+
+#if 0
+ /* Check that the sort worked */
+ {
+ int jj;
+ for(jj=1; jj<nIdx; jj++){
+ float left = aDistance[aIdx[jj-1]];
+ float right = aDistance[aIdx[jj]];
+ assert( left<=right );
+ }
+ }
+#endif
+ }
+}
+
+/*
+** Arguments aIdx, aCell and aSpare all point to arrays of size
+** nIdx. The aIdx array contains the set of integers from 0 to
+** (nIdx-1) in no particular order. This function sorts the values
+** in aIdx according to dimension iDim of the cells in aCell. The
+** minimum value of dimension iDim is considered first, the
+** maximum used to break ties.
+**
+** The aSpare array is used as temporary working space by the
+** sorting algorithm.
+*/
+static void SortByDimension(
+ Rtree *pRtree,
+ int *aIdx,
+ int nIdx,
+ int iDim,
+ RtreeCell *aCell,
+ int *aSpare
+){
+ if( nIdx>1 ){
+
+ int iLeft = 0;
+ int iRight = 0;
+
+ int nLeft = nIdx/2;
+ int nRight = nIdx-nLeft;
+ int *aLeft = aIdx;
+ int *aRight = &aIdx[nLeft];
+
+ SortByDimension(pRtree, aLeft, nLeft, iDim, aCell, aSpare);
+ SortByDimension(pRtree, aRight, nRight, iDim, aCell, aSpare);
+
+ memcpy(aSpare, aLeft, sizeof(int)*nLeft);
+ aLeft = aSpare;
+ while( iLeft<nLeft || iRight<nRight ){
+ double xleft1 = DCOORD(aCell[aLeft[iLeft]].aCoord[iDim*2]);
+ double xleft2 = DCOORD(aCell[aLeft[iLeft]].aCoord[iDim*2+1]);
+ double xright1 = DCOORD(aCell[aRight[iRight]].aCoord[iDim*2]);
+ double xright2 = DCOORD(aCell[aRight[iRight]].aCoord[iDim*2+1]);
+ if( (iLeft!=nLeft) && ((iRight==nRight)
+ || (xleft1<xright1)
+ || (xleft1==xright1 && xleft2<xright2)
+ )){
+ aIdx[iLeft+iRight] = aLeft[iLeft];
+ iLeft++;
+ }else{
+ aIdx[iLeft+iRight] = aRight[iRight];
+ iRight++;
+ }
+ }
+
+#if 0
+ /* Check that the sort worked */
+ {
+ int jj;
+ for(jj=1; jj<nIdx; jj++){
+ float xleft1 = aCell[aIdx[jj-1]].aCoord[iDim*2];
+ float xleft2 = aCell[aIdx[jj-1]].aCoord[iDim*2+1];
+ float xright1 = aCell[aIdx[jj]].aCoord[iDim*2];
+ float xright2 = aCell[aIdx[jj]].aCoord[iDim*2+1];
+ assert( xleft1<=xright1 && (xleft1<xright1 || xleft2<=xright2) );
+ }
+ }
+#endif
+ }
+}
+
+#if VARIANT_RSTARTREE_SPLIT
+/*
+** Implementation of the R*-tree variant of SplitNode from Beckman[1990].
+*/
+static int splitNodeStartree(
+ Rtree *pRtree,
+ RtreeCell *aCell,
+ int nCell,
+ RtreeNode *pLeft,
+ RtreeNode *pRight,
+ RtreeCell *pBboxLeft,
+ RtreeCell *pBboxRight
+){
+ int **aaSorted;
+ int *aSpare;
+ int ii;
+
+ int iBestDim;
+ int iBestSplit;
+ float fBestMargin;
+
+ int nByte = (pRtree->nDim+1)*(sizeof(int*)+nCell*sizeof(int));
+
+ aaSorted = (int **)sqlite3_malloc(nByte);
+ if( !aaSorted ){
+ return SQLITE_NOMEM;
+ }
+
+ aSpare = &((int *)&aaSorted[pRtree->nDim])[pRtree->nDim*nCell];
+ memset(aaSorted, 0, nByte);
+ for(ii=0; ii<pRtree->nDim; ii++){
+ int jj;
+ aaSorted[ii] = &((int *)&aaSorted[pRtree->nDim])[ii*nCell];
+ for(jj=0; jj<nCell; jj++){
+ aaSorted[ii][jj] = jj;
+ }
+ SortByDimension(pRtree, aaSorted[ii], nCell, ii, aCell, aSpare);
+ }
+
+ for(ii=0; ii<pRtree->nDim; ii++){
+ float margin = 0.0;
+ float fBestOverlap;
+ float fBestArea;
+ int iBestLeft;
+ int nLeft;
+
+ for(
+ nLeft=RTREE_MINCELLS(pRtree);
+ nLeft<=(nCell-RTREE_MINCELLS(pRtree));
+ nLeft++
+ ){
+ RtreeCell left;
+ RtreeCell right;
+ int kk;
+ float overlap;
+ float area;
+
+ memcpy(&left, &aCell[aaSorted[ii][0]], sizeof(RtreeCell));
+ memcpy(&right, &aCell[aaSorted[ii][nCell-1]], sizeof(RtreeCell));
+ for(kk=1; kk<(nCell-1); kk++){
+ if( kk<nLeft ){
+ cellUnion(pRtree, &left, &aCell[aaSorted[ii][kk]]);
+ }else{
+ cellUnion(pRtree, &right, &aCell[aaSorted[ii][kk]]);
+ }
+ }
+ margin += cellMargin(pRtree, &left);
+ margin += cellMargin(pRtree, &right);
+ overlap = cellOverlap(pRtree, &left, &right, 1, -1);
+ area = cellArea(pRtree, &left) + cellArea(pRtree, &right);
+ if( (nLeft==RTREE_MINCELLS(pRtree))
+ || (overlap<fBestOverlap)
+ || (overlap==fBestOverlap && area<fBestArea)
+ ){
+ iBestLeft = nLeft;
+ fBestOverlap = overlap;
+ fBestArea = area;
+ }
+ }
+
+ if( ii==0 || margin<fBestMargin ){
+ iBestDim = ii;
+ fBestMargin = margin;
+ iBestSplit = iBestLeft;
+ }
+ }
+
+ memcpy(pBboxLeft, &aCell[aaSorted[iBestDim][0]], sizeof(RtreeCell));
+ memcpy(pBboxRight, &aCell[aaSorted[iBestDim][iBestSplit]], sizeof(RtreeCell));
+ for(ii=0; ii<nCell; ii++){
+ RtreeNode *pTarget = (ii<iBestSplit)?pLeft:pRight;
+ RtreeCell *pBbox = (ii<iBestSplit)?pBboxLeft:pBboxRight;
+ RtreeCell *pCell = &aCell[aaSorted[iBestDim][ii]];
+ nodeInsertCell(pRtree, pTarget, pCell);
+ cellUnion(pRtree, pBbox, pCell);
+ }
+
+ sqlite3_free(aaSorted);
+ return SQLITE_OK;
+}
+#endif
+
+#if VARIANT_GUTTMAN_SPLIT
+/*
+** Implementation of the regular R-tree SplitNode from Guttman[1984].
+*/
+static int splitNodeGuttman(
+ Rtree *pRtree,
+ RtreeCell *aCell,
+ int nCell,
+ RtreeNode *pLeft,
+ RtreeNode *pRight,
+ RtreeCell *pBboxLeft,
+ RtreeCell *pBboxRight
+){
+ int iLeftSeed = 0;
+ int iRightSeed = 1;
+ int *aiUsed;
+ int i;
+
+ aiUsed = sqlite3_malloc(sizeof(int)*nCell);
+ memset(aiUsed, 0, sizeof(int)*nCell);
+
+ PickSeeds(pRtree, aCell, nCell, &iLeftSeed, &iRightSeed);
+
+ memcpy(pBboxLeft, &aCell[iLeftSeed], sizeof(RtreeCell));
+ memcpy(pBboxRight, &aCell[iRightSeed], sizeof(RtreeCell));
+ nodeInsertCell(pRtree, pLeft, &aCell[iLeftSeed]);
+ nodeInsertCell(pRtree, pRight, &aCell[iRightSeed]);
+ aiUsed[iLeftSeed] = 1;
+ aiUsed[iRightSeed] = 1;
+
+ for(i=nCell-2; i>0; i--){
+ RtreeCell *pNext;
+ pNext = PickNext(pRtree, aCell, nCell, pBboxLeft, pBboxRight, aiUsed);
+ float diff =
+ cellGrowth(pRtree, pBboxLeft, pNext) -
+ cellGrowth(pRtree, pBboxRight, pNext)
+ ;
+ if( (RTREE_MINCELLS(pRtree)-NCELL(pRight)==i)
+ || (diff>0.0 && (RTREE_MINCELLS(pRtree)-NCELL(pLeft)!=i))
+ ){
+ nodeInsertCell(pRtree, pRight, pNext);
+ cellUnion(pRtree, pBboxRight, pNext);
+ }else{
+ nodeInsertCell(pRtree, pLeft, pNext);
+ cellUnion(pRtree, pBboxLeft, pNext);
+ }
+ }
+
+ sqlite3_free(aiUsed);
+ return SQLITE_OK;
+}
+#endif
+
+static int updateMapping(
+ Rtree *pRtree,
+ i64 iRowid,
+ RtreeNode *pNode,
+ int iHeight
+){
+ int (*xSetMapping)(Rtree *, sqlite3_int64, sqlite3_int64);
+ xSetMapping = ((iHeight==0)?rowidWrite:parentWrite);
+ if( iHeight>0 ){
+ RtreeNode *pChild = nodeHashLookup(pRtree, iRowid);
+ if( pChild ){
+ nodeRelease(pRtree, pChild->pParent);
+ nodeReference(pNode);
+ pChild->pParent = pNode;
+ }
+ }
+ return xSetMapping(pRtree, iRowid, pNode->iNode);
+}
+
+static int SplitNode(
+ Rtree *pRtree,
+ RtreeNode *pNode,
+ RtreeCell *pCell,
+ int iHeight
+){
+ int i;
+ int newCellIsRight = 0;
+
+ int rc = SQLITE_OK;
+ int nCell = NCELL(pNode);
+ RtreeCell *aCell;
+ int *aiUsed;
+
+ RtreeNode *pLeft = 0;
+ RtreeNode *pRight = 0;
+
+ RtreeCell leftbbox;
+ RtreeCell rightbbox;
+
+ /* Allocate an array and populate it with a copy of pCell and
+ ** all cells from node pLeft. Then zero the original node.
+ */
+ aCell = sqlite3_malloc((sizeof(RtreeCell)+sizeof(int))*(nCell+1));
+ if( !aCell ){
+ rc = SQLITE_NOMEM;
+ goto splitnode_out;
+ }
+ aiUsed = (int *)&aCell[nCell+1];
+ memset(aiUsed, 0, sizeof(int)*(nCell+1));
+ for(i=0; i<nCell; i++){
+ nodeGetCell(pRtree, pNode, i, &aCell[i]);
+ }
+ nodeZero(pRtree, pNode);
+ memcpy(&aCell[nCell], pCell, sizeof(RtreeCell));
+ nCell++;
+
+ if( pNode->iNode==1 ){
+ pRight = nodeNew(pRtree, pNode, 1);
+ pLeft = nodeNew(pRtree, pNode, 1);
+ pRtree->iDepth++;
+ pNode->isDirty = 1;
+ writeInt16(pNode->zData, pRtree->iDepth);
+ }else{
+ pLeft = pNode;
+ pRight = nodeNew(pRtree, pLeft->pParent, 1);
+ nodeReference(pLeft);
+ }
+
+ if( !pLeft || !pRight ){
+ rc = SQLITE_NOMEM;
+ goto splitnode_out;
+ }
+
+ memset(pLeft->zData, 0, pRtree->iNodeSize);
+ memset(pRight->zData, 0, pRtree->iNodeSize);
+
+ rc = AssignCells(pRtree, aCell, nCell, pLeft, pRight, &leftbbox, &rightbbox);
+ if( rc!=SQLITE_OK ){
+ goto splitnode_out;
+ }
+
+ /* Ensure both child nodes have node numbers assigned to them. */
+ if( (0==pRight->iNode && SQLITE_OK!=(rc = nodeWrite(pRtree, pRight)))
+ || (0==pLeft->iNode && SQLITE_OK!=(rc = nodeWrite(pRtree, pLeft)))
+ ){
+ goto splitnode_out;
+ }
+
+ rightbbox.iRowid = pRight->iNode;
+ leftbbox.iRowid = pLeft->iNode;
+
+ if( pNode->iNode==1 ){
+ rc = rtreeInsertCell(pRtree, pLeft->pParent, &leftbbox, iHeight+1);
+ if( rc!=SQLITE_OK ){
+ goto splitnode_out;
+ }
+ }else{
+ RtreeNode *pParent = pLeft->pParent;
+ int iCell = nodeParentIndex(pRtree, pLeft);
+ nodeOverwriteCell(pRtree, pParent, &leftbbox, iCell);
+ AdjustTree(pRtree, pParent, &leftbbox);
+ }
+ if( (rc = rtreeInsertCell(pRtree, pRight->pParent, &rightbbox, iHeight+1)) ){
+ goto splitnode_out;
+ }
+
+ for(i=0; i<NCELL(pRight); i++){
+ i64 iRowid = nodeGetRowid(pRtree, pRight, i);
+ rc = updateMapping(pRtree, iRowid, pRight, iHeight);
+ if( iRowid==pCell->iRowid ){
+ newCellIsRight = 1;
+ }
+ if( rc!=SQLITE_OK ){
+ goto splitnode_out;
+ }
+ }
+ if( pNode->iNode==1 ){
+ for(i=0; i<NCELL(pLeft); i++){
+ i64 iRowid = nodeGetRowid(pRtree, pLeft, i);
+ rc = updateMapping(pRtree, iRowid, pLeft, iHeight);
+ if( rc!=SQLITE_OK ){
+ goto splitnode_out;
+ }
+ }
+ }else if( newCellIsRight==0 ){
+ rc = updateMapping(pRtree, pCell->iRowid, pLeft, iHeight);
+ }
+
+ if( rc==SQLITE_OK ){
+ rc = nodeRelease(pRtree, pRight);
+ pRight = 0;
+ }
+ if( rc==SQLITE_OK ){
+ rc = nodeRelease(pRtree, pLeft);
+ pLeft = 0;
+ }
+
+splitnode_out:
+ nodeRelease(pRtree, pRight);
+ nodeRelease(pRtree, pLeft);
+ sqlite3_free(aCell);
+ return rc;
+}
+
+static int fixLeafParent(Rtree *pRtree, RtreeNode *pLeaf){
+ int rc = SQLITE_OK;
+ if( pLeaf->iNode!=1 && pLeaf->pParent==0 ){
+ sqlite3_bind_int64(pRtree->pReadParent, 1, pLeaf->iNode);
+ if( sqlite3_step(pRtree->pReadParent)==SQLITE_ROW ){
+ i64 iNode = sqlite3_column_int64(pRtree->pReadParent, 0);
+ rc = nodeAcquire(pRtree, iNode, 0, &pLeaf->pParent);
+ }else{
+ rc = SQLITE_ERROR;
+ }
+ sqlite3_reset(pRtree->pReadParent);
+ if( rc==SQLITE_OK ){
+ rc = fixLeafParent(pRtree, pLeaf->pParent);
+ }
+ }
+ return rc;
+}
+
+static int deleteCell(Rtree *, RtreeNode *, int, int);
+
+static int removeNode(Rtree *pRtree, RtreeNode *pNode, int iHeight){
+ int rc;
+ RtreeNode *pParent;
+ int iCell;
+
+ assert( pNode->nRef==1 );
+
+ /* Remove the entry in the parent cell. */
+ iCell = nodeParentIndex(pRtree, pNode);
+ pParent = pNode->pParent;
+ pNode->pParent = 0;
+ if( SQLITE_OK!=(rc = deleteCell(pRtree, pParent, iCell, iHeight+1))
+ || SQLITE_OK!=(rc = nodeRelease(pRtree, pParent))
+ ){
+ return rc;
+ }
+
+ /* Remove the xxx_node entry. */
+ sqlite3_bind_int64(pRtree->pDeleteNode, 1, pNode->iNode);
+ sqlite3_step(pRtree->pDeleteNode);
+ if( SQLITE_OK!=(rc = sqlite3_reset(pRtree->pDeleteNode)) ){
+ return rc;
+ }
+
+ /* Remove the xxx_parent entry. */
+ sqlite3_bind_int64(pRtree->pDeleteParent, 1, pNode->iNode);
+ sqlite3_step(pRtree->pDeleteParent);
+ if( SQLITE_OK!=(rc = sqlite3_reset(pRtree->pDeleteParent)) ){
+ return rc;
+ }
+
+ /* Remove the node from the in-memory hash table and link it into
+ ** the Rtree.pDeleted list. Its contents will be re-inserted later on.
+ */
+ nodeHashDelete(pRtree, pNode);
+ pNode->iNode = iHeight;
+ pNode->pNext = pRtree->pDeleted;
+ pNode->nRef++;
+ pRtree->pDeleted = pNode;
+
+ return SQLITE_OK;
+}
+
+static void fixBoundingBox(Rtree *pRtree, RtreeNode *pNode){
+ RtreeNode *pParent = pNode->pParent;
+ if( pParent ){
+ int ii;
+ int nCell = NCELL(pNode);
+ RtreeCell box; /* Bounding box for pNode */
+ nodeGetCell(pRtree, pNode, 0, &box);
+ for(ii=1; ii<nCell; ii++){
+ RtreeCell cell;
+ nodeGetCell(pRtree, pNode, ii, &cell);
+ cellUnion(pRtree, &box, &cell);
+ }
+ box.iRowid = pNode->iNode;
+ ii = nodeParentIndex(pRtree, pNode);
+ nodeOverwriteCell(pRtree, pParent, &box, ii);
+ fixBoundingBox(pRtree, pParent);
+ }
+}
+
+/*
+** Delete the cell at index iCell of node pNode. After removing the
+** cell, adjust the r-tree data structure if required.
+*/
+static int deleteCell(Rtree *pRtree, RtreeNode *pNode, int iCell, int iHeight){
+ int rc;
+
+ if( SQLITE_OK!=(rc = fixLeafParent(pRtree, pNode)) ){
+ return rc;
+ }
+
+ /* Remove the cell from the node. This call just moves bytes around
+ ** the in-memory node image, so it cannot fail.
+ */
+ nodeDeleteCell(pRtree, pNode, iCell);
+
+ /* If the node is not the tree root and now has less than the minimum
+ ** number of cells, remove it from the tree. Otherwise, update the
+ ** cell in the parent node so that it tightly contains the updated
+ ** node.
+ */
+ if( pNode->iNode!=1 ){
+ RtreeNode *pParent = pNode->pParent;
+ if( (pParent->iNode!=1 || NCELL(pParent)!=1)
+ && (NCELL(pNode)<RTREE_MINCELLS(pRtree))
+ ){
+ rc = removeNode(pRtree, pNode, iHeight);
+ }else{
+ fixBoundingBox(pRtree, pNode);
+ }
+ }
+
+ return rc;
+}
+
+static int Reinsert(
+ Rtree *pRtree,
+ RtreeNode *pNode,
+ RtreeCell *pCell,
+ int iHeight
+){
+ int *aOrder;
+ int *aSpare;
+ RtreeCell *aCell;
+ float *aDistance;
+ int nCell;
+ float aCenterCoord[RTREE_MAX_DIMENSIONS];
+ int iDim;
+ int ii;
+ int rc = SQLITE_OK;
+
+ memset(aCenterCoord, 0, sizeof(float)*RTREE_MAX_DIMENSIONS);
+
+ nCell = NCELL(pNode)+1;
+
+ /* Allocate the buffers used by this operation. The allocation is
+ ** relinquished before this function returns.
+ */
+ aCell = (RtreeCell *)sqlite3_malloc(nCell * (
+ sizeof(RtreeCell) + /* aCell array */
+ sizeof(int) + /* aOrder array */
+ sizeof(int) + /* aSpare array */
+ sizeof(float) /* aDistance array */
+ ));
+ if( !aCell ){
+ return SQLITE_NOMEM;
+ }
+ aOrder = (int *)&aCell[nCell];
+ aSpare = (int *)&aOrder[nCell];
+ aDistance = (float *)&aSpare[nCell];
+
+ for(ii=0; ii<nCell; ii++){
+ if( ii==(nCell-1) ){
+ memcpy(&aCell[ii], pCell, sizeof(RtreeCell));
+ }else{
+ nodeGetCell(pRtree, pNode, ii, &aCell[ii]);
+ }
+ aOrder[ii] = ii;
+ for(iDim=0; iDim<pRtree->nDim; iDim++){
+ aCenterCoord[iDim] += DCOORD(aCell[ii].aCoord[iDim*2]);
+ aCenterCoord[iDim] += DCOORD(aCell[ii].aCoord[iDim*2+1]);
+ }
+ }
+ for(iDim=0; iDim<pRtree->nDim; iDim++){
+ aCenterCoord[iDim] = aCenterCoord[iDim]/((float)nCell*2.0);
+ }
+
+ for(ii=0; ii<nCell; ii++){
+ aDistance[ii] = 0.0;
+ for(iDim=0; iDim<pRtree->nDim; iDim++){
+ float coord = DCOORD(aCell[ii].aCoord[iDim*2+1]) -
+ DCOORD(aCell[ii].aCoord[iDim*2]);
+ aDistance[ii] += (coord-aCenterCoord[iDim])*(coord-aCenterCoord[iDim]);
+ }
+ }
+
+ SortByDistance(aOrder, nCell, aDistance, aSpare);
+ nodeZero(pRtree, pNode);
+
+ for(ii=0; rc==SQLITE_OK && ii<(nCell-(RTREE_MINCELLS(pRtree)+1)); ii++){
+ RtreeCell *p = &aCell[aOrder[ii]];
+ nodeInsertCell(pRtree, pNode, p);
+ if( p->iRowid==pCell->iRowid ){
+ if( iHeight==0 ){
+ rc = rowidWrite(pRtree, p->iRowid, pNode->iNode);
+ }else{
+ rc = parentWrite(pRtree, p->iRowid, pNode->iNode);
+ }
+ }
+ }
+ if( rc==SQLITE_OK ){
+ fixBoundingBox(pRtree, pNode);
+ }
+ for(; rc==SQLITE_OK && ii<nCell; ii++){
+ /* Find a node to store this cell in. pNode->iNode currently contains
+ ** the height of the sub-tree headed by the cell.
+ */
+ RtreeNode *pInsert;
+ RtreeCell *p = &aCell[aOrder[ii]];
+ rc = ChooseLeaf(pRtree, p, iHeight, &pInsert);
+ if( rc==SQLITE_OK ){
+ int rc2;
+ rc = rtreeInsertCell(pRtree, pInsert, p, iHeight);
+ rc2 = nodeRelease(pRtree, pInsert);
+ if( rc==SQLITE_OK ){
+ rc = rc2;
+ }
+ }
+ }
+
+ sqlite3_free(aCell);
+ return rc;
+}
+
+/*
+** Insert cell pCell into node pNode. Node pNode is the head of a
+** subtree iHeight high (leaf nodes have iHeight==0).
+*/
+static int rtreeInsertCell(
+ Rtree *pRtree,
+ RtreeNode *pNode,
+ RtreeCell *pCell,
+ int iHeight
+){
+ int rc = SQLITE_OK;
+ if( iHeight>0 ){
+ RtreeNode *pChild = nodeHashLookup(pRtree, pCell->iRowid);
+ if( pChild ){
+ nodeRelease(pRtree, pChild->pParent);
+ nodeReference(pNode);
+ pChild->pParent = pNode;
+ }
+ }
+ if( nodeInsertCell(pRtree, pNode, pCell) ){
+#if VARIANT_RSTARTREE_REINSERT
+ if( iHeight<=pRtree->iReinsertHeight || pNode->iNode==1){
+ rc = SplitNode(pRtree, pNode, pCell, iHeight);
+ }else{
+ pRtree->iReinsertHeight = iHeight;
+ rc = Reinsert(pRtree, pNode, pCell, iHeight);
+ }
+#else
+ rc = SplitNode(pRtree, pNode, pCell, iHeight);
+#endif
+ }else{
+ AdjustTree(pRtree, pNode, pCell);
+ if( iHeight==0 ){
+ rc = rowidWrite(pRtree, pCell->iRowid, pNode->iNode);
+ }else{
+ rc = parentWrite(pRtree, pCell->iRowid, pNode->iNode);
+ }
+ }
+ return rc;
+}
+
+static int reinsertNodeContent(Rtree *pRtree, RtreeNode *pNode){
+ int ii;
+ int rc = SQLITE_OK;
+ int nCell = NCELL(pNode);
+
+ for(ii=0; rc==SQLITE_OK && ii<nCell; ii++){
+ RtreeNode *pInsert;
+ RtreeCell cell;
+ nodeGetCell(pRtree, pNode, ii, &cell);
+
+ /* Find a node to store this cell in. pNode->iNode currently contains
+ ** the height of the sub-tree headed by the cell.
+ */
+ rc = ChooseLeaf(pRtree, &cell, pNode->iNode, &pInsert);
+ if( rc==SQLITE_OK ){
+ int rc2;
+ rc = rtreeInsertCell(pRtree, pInsert, &cell, pNode->iNode);
+ rc2 = nodeRelease(pRtree, pInsert);
+ if( rc==SQLITE_OK ){
+ rc = rc2;
+ }
+ }
+ }
+ return rc;
+}
+
+/*
+** Select a currently unused rowid for a new r-tree record.
+*/
+static int newRowid(Rtree *pRtree, i64 *piRowid){
+ int rc;
+ sqlite3_bind_null(pRtree->pWriteRowid, 1);
+ sqlite3_bind_null(pRtree->pWriteRowid, 2);
+ sqlite3_step(pRtree->pWriteRowid);
+ rc = sqlite3_reset(pRtree->pWriteRowid);
+ *piRowid = sqlite3_last_insert_rowid(pRtree->db);
+ return rc;
+}
+
+#ifndef NDEBUG
+static int hashIsEmpty(Rtree *pRtree){
+ int ii;
+ for(ii=0; ii<HASHSIZE; ii++){
+ assert( !pRtree->aHash[ii] );
+ }
+ return 1;
+}
+#endif
+
+/*
+** The xUpdate method for rtree module virtual tables.
+*/
+int rtreeUpdate(
+ sqlite3_vtab *pVtab,
+ int nData,
+ sqlite3_value **azData,
+ sqlite_int64 *pRowid
+){
+ Rtree *pRtree = (Rtree *)pVtab;
+ int rc = SQLITE_OK;
+
+ rtreeReference(pRtree);
+
+ assert(nData>=1);
+ assert(hashIsEmpty(pRtree));
+
+ /* If azData[0] is not an SQL NULL value, it is the rowid of a
+ ** record to delete from the r-tree table. The following block does
+ ** just that.
+ */
+ if( sqlite3_value_type(azData[0])!=SQLITE_NULL ){
+ i64 iDelete; /* The rowid to delete */
+ RtreeNode *pLeaf; /* Leaf node containing record iDelete */
+ int iCell; /* Index of iDelete cell in pLeaf */
+ RtreeNode *pRoot;
+
+ /* Obtain a reference to the root node to initialise Rtree.iDepth */
+ rc = nodeAcquire(pRtree, 1, 0, &pRoot);
+
+ /* Obtain a reference to the leaf node that contains the entry
+ ** about to be deleted.
+ */
+ if( rc==SQLITE_OK ){
+ iDelete = sqlite3_value_int64(azData[0]);
+ rc = findLeafNode(pRtree, iDelete, &pLeaf);
+ }
+
+ /* Delete the cell in question from the leaf node. */
+ if( rc==SQLITE_OK ){
+ int rc2;
+ iCell = nodeRowidIndex(pRtree, pLeaf, iDelete);
+ rc = deleteCell(pRtree, pLeaf, iCell, 0);
+ rc2 = nodeRelease(pRtree, pLeaf);
+ if( rc==SQLITE_OK ){
+ rc = rc2;
+ }
+ }
+
+ /* Delete the corresponding entry in the <rtree>_rowid table. */
+ if( rc==SQLITE_OK ){
+ sqlite3_bind_int64(pRtree->pDeleteRowid, 1, iDelete);
+ sqlite3_step(pRtree->pDeleteRowid);
+ rc = sqlite3_reset(pRtree->pDeleteRowid);
+ }
+
+ /* Check if the root node now has exactly one child. If so, remove
+ ** it, schedule the contents of the child for reinsertion and
+ ** reduce the tree height by one.
+ **
+ ** This is equivalent to copying the contents of the child into
+ ** the root node (the operation that Gutman's paper says to perform
+ ** in this scenario).
+ */
+ if( rc==SQLITE_OK && pRtree->iDepth>0 ){
+ if( rc==SQLITE_OK && NCELL(pRoot)==1 ){
+ RtreeNode *pChild;
+ i64 iChild = nodeGetRowid(pRtree, pRoot, 0);
+ rc = nodeAcquire(pRtree, iChild, pRoot, &pChild);
+ if( rc==SQLITE_OK ){
+ rc = removeNode(pRtree, pChild, pRtree->iDepth-1);
+ }
+ if( rc==SQLITE_OK ){
+ pRtree->iDepth--;
+ writeInt16(pRoot->zData, pRtree->iDepth);
+ pRoot->isDirty = 1;
+ }
+ }
+ }
+
+ /* Re-insert the contents of any underfull nodes removed from the tree. */
+ for(pLeaf=pRtree->pDeleted; pLeaf; pLeaf=pRtree->pDeleted){
+ if( rc==SQLITE_OK ){
+ rc = reinsertNodeContent(pRtree, pLeaf);
+ }
+ pRtree->pDeleted = pLeaf->pNext;
+ sqlite3_free(pLeaf);
+ }
+
+ /* Release the reference to the root node. */
+ if( rc==SQLITE_OK ){
+ rc = nodeRelease(pRtree, pRoot);
+ }else{
+ nodeRelease(pRtree, pRoot);
+ }
+ }
+
+ /* If the azData[] array contains more than one element, elements
+ ** (azData[2]..azData[argc-1]) contain a new record to insert into
+ ** the r-tree structure.
+ */
+ if( rc==SQLITE_OK && nData>1 ){
+ /* Insert a new record into the r-tree */
+ RtreeCell cell;
+ int ii;
+ RtreeNode *pLeaf;
+
+ /* Populate the cell.aCoord[] array. The first coordinate is azData[3]. */
+ assert( nData==(pRtree->nDim*2 + 3) );
+ if( pRtree->eCoordType==RTREE_COORD_REAL32 ){
+ for(ii=0; ii<(pRtree->nDim*2); ii+=2){
+ cell.aCoord[ii].f = (float)sqlite3_value_double(azData[ii+3]);
+ cell.aCoord[ii+1].f = (float)sqlite3_value_double(azData[ii+4]);
+ if( cell.aCoord[ii].f>cell.aCoord[ii+1].f ){
+ rc = SQLITE_CONSTRAINT;
+ goto constraint;
+ }
+ }
+ }else{
+ for(ii=0; ii<(pRtree->nDim*2); ii+=2){
+ cell.aCoord[ii].i = sqlite3_value_int(azData[ii+3]);
+ cell.aCoord[ii+1].i = sqlite3_value_int(azData[ii+4]);
+ if( cell.aCoord[ii].i>cell.aCoord[ii+1].i ){
+ rc = SQLITE_CONSTRAINT;
+ goto constraint;
+ }
+ }
+ }
+
+ /* Figure out the rowid of the new row. */
+ if( sqlite3_value_type(azData[2])==SQLITE_NULL ){
+ rc = newRowid(pRtree, &cell.iRowid);
+ }else{
+ cell.iRowid = sqlite3_value_int64(azData[2]);
+ sqlite3_bind_int64(pRtree->pReadRowid, 1, cell.iRowid);
+ if( SQLITE_ROW==sqlite3_step(pRtree->pReadRowid) ){
+ sqlite3_reset(pRtree->pReadRowid);
+ rc = SQLITE_CONSTRAINT;
+ goto constraint;
+ }
+ rc = sqlite3_reset(pRtree->pReadRowid);
+ }
+
+ if( rc==SQLITE_OK ){
+ rc = ChooseLeaf(pRtree, &cell, 0, &pLeaf);
+ }
+ if( rc==SQLITE_OK ){
+ int rc2;
+ pRtree->iReinsertHeight = -1;
+ rc = rtreeInsertCell(pRtree, pLeaf, &cell, 0);
+ rc2 = nodeRelease(pRtree, pLeaf);
+ if( rc==SQLITE_OK ){
+ rc = rc2;
+ }
+ }
+ }
+
+constraint:
+ rtreeRelease(pRtree);
+ return rc;
+}
+
+/*
+** The xRename method for rtree module virtual tables.
+*/
+static int rtreeRename(sqlite3_vtab *pVtab, const char *zNewName){
+ Rtree *pRtree = (Rtree *)pVtab;
+ int rc = SQLITE_NOMEM;
+ char *zSql = sqlite3_mprintf(
+ "ALTER TABLE %Q.'%q_node' RENAME TO \"%w_node\";"
+ "ALTER TABLE %Q.'%q_parent' RENAME TO \"%w_parent\";"
+ "ALTER TABLE %Q.'%q_rowid' RENAME TO \"%w_rowid\";"
+ , pRtree->zDb, pRtree->zName, zNewName
+ , pRtree->zDb, pRtree->zName, zNewName
+ , pRtree->zDb, pRtree->zName, zNewName
+ );
+ if( zSql ){
+ rc = sqlite3_exec(pRtree->db, zSql, 0, 0, 0);
+ sqlite3_free(zSql);
+ }
+ return rc;
+}
+
+static sqlite3_module rtreeModule = {
+ 0, /* iVersion */
+ rtreeCreate, /* xCreate - create a table */
+ rtreeConnect, /* xConnect - connect to an existing table */
+ rtreeBestIndex, /* xBestIndex - Determine search strategy */
+ rtreeDisconnect, /* xDisconnect - Disconnect from a table */
+ rtreeDestroy, /* xDestroy - Drop a table */
+ rtreeOpen, /* xOpen - open a cursor */
+ rtreeClose, /* xClose - close a cursor */
+ rtreeFilter, /* xFilter - configure scan constraints */
+ rtreeNext, /* xNext - advance a cursor */
+ rtreeEof, /* xEof */
+ rtreeColumn, /* xColumn - read data */
+ rtreeRowid, /* xRowid - read data */
+ rtreeUpdate, /* xUpdate - write data */
+ 0, /* xBegin - begin transaction */
+ 0, /* xSync - sync transaction */
+ 0, /* xCommit - commit transaction */
+ 0, /* xRollback - rollback transaction */
+ 0, /* xFindFunction - function overloading */
+ rtreeRename /* xRename - rename the table */
+};
+
+static int rtreeSqlInit(
+ Rtree *pRtree,
+ sqlite3 *db,
+ const char *zDb,
+ const char *zPrefix,
+ int isCreate
+){
+ int rc = SQLITE_OK;
+
+ #define N_STATEMENT 9
+ static const char *azSql[N_STATEMENT] = {
+ /* Read and write the xxx_node table */
+ "SELECT data FROM '%q'.'%q_node' WHERE nodeno = :1",
+ "INSERT OR REPLACE INTO '%q'.'%q_node' VALUES(:1, :2)",
+ "DELETE FROM '%q'.'%q_node' WHERE nodeno = :1",
+
+ /* Read and write the xxx_rowid table */
+ "SELECT nodeno FROM '%q'.'%q_rowid' WHERE rowid = :1",
+ "INSERT OR REPLACE INTO '%q'.'%q_rowid' VALUES(:1, :2)",
+ "DELETE FROM '%q'.'%q_rowid' WHERE rowid = :1",
+
+ /* Read and write the xxx_parent table */
+ "SELECT parentnode FROM '%q'.'%q_parent' WHERE nodeno = :1",
+ "INSERT OR REPLACE INTO '%q'.'%q_parent' VALUES(:1, :2)",
+ "DELETE FROM '%q'.'%q_parent' WHERE nodeno = :1"
+ };
+ sqlite3_stmt **appStmt[N_STATEMENT];
+ int i;
+
+ pRtree->db = db;
+
+ if( isCreate ){
+ char *zCreate = sqlite3_mprintf(
+"CREATE TABLE \"%w\".\"%w_node\"(nodeno INTEGER PRIMARY KEY, data BLOB);"
+"CREATE TABLE \"%w\".\"%w_rowid\"(rowid INTEGER PRIMARY KEY, nodeno INTEGER);"
+"CREATE TABLE \"%w\".\"%w_parent\"(nodeno INTEGER PRIMARY KEY, parentnode INTEGER);"
+"INSERT INTO '%q'.'%q_node' VALUES(1, zeroblob(%d))",
+ zDb, zPrefix, zDb, zPrefix, zDb, zPrefix, zDb, zPrefix, pRtree->iNodeSize
+ );
+ if( !zCreate ){
+ return SQLITE_NOMEM;
+ }
+ rc = sqlite3_exec(db, zCreate, 0, 0, 0);
+ sqlite3_free(zCreate);
+ if( rc!=SQLITE_OK ){
+ return rc;
+ }
+ }
+
+ appStmt[0] = &pRtree->pReadNode;
+ appStmt[1] = &pRtree->pWriteNode;
+ appStmt[2] = &pRtree->pDeleteNode;
+ appStmt[3] = &pRtree->pReadRowid;
+ appStmt[4] = &pRtree->pWriteRowid;
+ appStmt[5] = &pRtree->pDeleteRowid;
+ appStmt[6] = &pRtree->pReadParent;
+ appStmt[7] = &pRtree->pWriteParent;
+ appStmt[8] = &pRtree->pDeleteParent;
+
+ for(i=0; i<N_STATEMENT && rc==SQLITE_OK; i++){
+ char *zSql = sqlite3_mprintf(azSql[i], zDb, zPrefix);
+ if( zSql ){
+ rc = sqlite3_prepare_v2(db, zSql, -1, appStmt[i], 0);
+ }else{
+ rc = SQLITE_NOMEM;
+ }
+ sqlite3_free(zSql);
+ }
+
+ return rc;
+}
+
+/*
+** This routine queries database handle db for the page-size used by
+** database zDb. If successful, the page-size in bytes is written to
+** *piPageSize and SQLITE_OK returned. Otherwise, and an SQLite error
+** code is returned.
+*/
+static int getPageSize(sqlite3 *db, const char *zDb, int *piPageSize){
+ int rc = SQLITE_NOMEM;
+ char *zSql;
+ sqlite3_stmt *pStmt = 0;
+
+ zSql = sqlite3_mprintf("PRAGMA %Q.page_size", zDb);
+ if( !zSql ){
+ return SQLITE_NOMEM;
+ }
+
+ rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0);
+ sqlite3_free(zSql);
+ if( rc!=SQLITE_OK ){
+ return rc;
+ }
+
+ if( SQLITE_ROW==sqlite3_step(pStmt) ){
+ *piPageSize = sqlite3_column_int(pStmt, 0);
+ }
+ return sqlite3_finalize(pStmt);
+}
+
+/*
+** This function is the implementation of both the xConnect and xCreate
+** methods of the r-tree virtual table.
+**
+** argv[0] -> module name
+** argv[1] -> database name
+** argv[2] -> table name
+** argv[...] -> column names...
+*/
+static int rtreeInit(
+ sqlite3 *db, /* Database connection */
+ void *pAux, /* Pointer to head of rtree list */
+ int argc, const char *const*argv, /* Parameters to CREATE TABLE statement */
+ sqlite3_vtab **ppVtab, /* OUT: New virtual table */
+ char **pzErr, /* OUT: Error message, if any */
+ int isCreate, /* True for xCreate, false for xConnect */
+ int eCoordType /* One of the RTREE_COORD_* constants */
+){
+ int rc = SQLITE_OK;
+ int iPageSize = 0;
+ Rtree *pRtree;
+ int nDb; /* Length of string argv[1] */
+ int nName; /* Length of string argv[2] */
+
+ const char *aErrMsg[] = {
+ 0, /* 0 */
+ "Wrong number of columns for an rtree table", /* 1 */
+ "Too few columns for an rtree table", /* 2 */
+ "Too many columns for an rtree table" /* 3 */
+ };
+
+ int iErr = (argc<6) ? 2 : argc>(RTREE_MAX_DIMENSIONS*2+4) ? 3 : argc%2;
+ if( aErrMsg[iErr] ){
+ *pzErr = sqlite3_mprintf("%s", aErrMsg[iErr]);
+ return SQLITE_ERROR;
+ }
+
+ rc = getPageSize(db, argv[1], &iPageSize);
+ if( rc!=SQLITE_OK ){
+ return rc;
+ }
+
+ /* Allocate the sqlite3_vtab structure */
+ nDb = strlen(argv[1]);
+ nName = strlen(argv[2]);
+ pRtree = (Rtree *)sqlite3_malloc(sizeof(Rtree)+nDb+nName+2);
+ if( !pRtree ){
+ return SQLITE_NOMEM;
+ }
+ memset(pRtree, 0, sizeof(Rtree)+nDb+nName+2);
+ pRtree->nBusy = 1;
+ pRtree->base.pModule = &rtreeModule;
+ pRtree->zDb = (char *)&pRtree[1];
+ pRtree->zName = &pRtree->zDb[nDb+1];
+ pRtree->nDim = (argc-4)/2;
+ pRtree->nBytesPerCell = 8 + pRtree->nDim*4*2;
+ pRtree->eCoordType = eCoordType;
+ memcpy(pRtree->zDb, argv[1], nDb);
+ memcpy(pRtree->zName, argv[2], nName);
+
+ /* Figure out the node size to use. By default, use 64 bytes less than
+ ** the database page-size. This ensures that each node is stored on
+ ** a single database page.
+ **
+ ** If the databasd page-size is so large that more than RTREE_MAXCELLS
+ ** entries would fit in a single node, use a smaller node-size.
+ */
+ pRtree->iNodeSize = iPageSize-64;
+ if( (4+pRtree->nBytesPerCell*RTREE_MAXCELLS)<pRtree->iNodeSize ){
+ pRtree->iNodeSize = 4+pRtree->nBytesPerCell*RTREE_MAXCELLS;
+ }
+
+ /* Create/Connect to the underlying relational database schema. If
+ ** that is successful, call sqlite3_declare_vtab() to configure
+ ** the r-tree table schema.
+ */
+ if( (rc = rtreeSqlInit(pRtree, db, argv[1], argv[2], isCreate)) ){
+ *pzErr = sqlite3_mprintf("%s", sqlite3_errmsg(db));
+ }else{
+ char *zSql = sqlite3_mprintf("CREATE TABLE x(%s", argv[3]);
+ char *zTmp;
+ int ii;
+ for(ii=4; zSql && ii<argc; ii++){
+ zTmp = zSql;
+ zSql = sqlite3_mprintf("%s, %s", zTmp, argv[ii]);
+ sqlite3_free(zTmp);
+ }
+ if( zSql ){
+ zTmp = zSql;
+ zSql = sqlite3_mprintf("%s);", zTmp);
+ sqlite3_free(zTmp);
+ }
+ if( !zSql || sqlite3_declare_vtab(db, zSql) ){
+ rc = SQLITE_NOMEM;
+ }
+ sqlite3_free(zSql);
+ }
+
+ if( rc==SQLITE_OK ){
+ *ppVtab = (sqlite3_vtab *)pRtree;
+ }else{
+ rtreeRelease(pRtree);
+ }
+ return rc;
+}
+
+
+/*
+** Implementation of a scalar function that decodes r-tree nodes to
+** human readable strings. This can be used for debugging and analysis.
+**
+** The scalar function takes two arguments, a blob of data containing
+** an r-tree node, and the number of dimensions the r-tree indexes.
+** For a two-dimensional r-tree structure called "rt", to deserialize
+** all nodes, a statement like:
+**
+** SELECT rtreenode(2, data) FROM rt_node;
+**
+** The human readable string takes the form of a Tcl list with one
+** entry for each cell in the r-tree node. Each entry is itself a
+** list, containing the 8-byte rowid/pageno followed by the
+** <num-dimension>*2 coordinates.
+*/
+static void rtreenode(sqlite3_context *ctx, int nArg, sqlite3_value **apArg){
+ char *zText = 0;
+ RtreeNode node;
+ Rtree tree;
+ int ii;
+
+ memset(&node, 0, sizeof(RtreeNode));
+ memset(&tree, 0, sizeof(Rtree));
+ tree.nDim = sqlite3_value_int(apArg[0]);
+ tree.nBytesPerCell = 8 + 8 * tree.nDim;
+ node.zData = (u8 *)sqlite3_value_blob(apArg[1]);
+
+ for(ii=0; ii<NCELL(&node); ii++){
+ char zCell[512];
+ int nCell = 0;
+ RtreeCell cell;
+ int jj;
+
+ nodeGetCell(&tree, &node, ii, &cell);
+ sqlite3_snprintf(512-nCell,&zCell[nCell],"%d", cell.iRowid);
+ nCell = strlen(zCell);
+ for(jj=0; jj<tree.nDim*2; jj++){
+ sqlite3_snprintf(512-nCell,&zCell[nCell]," %f",(double)cell.aCoord[jj].f);
+ nCell = strlen(zCell);
+ }
+
+ if( zText ){
+ char *zTextNew = sqlite3_mprintf("%s {%s}", zText, zCell);
+ sqlite3_free(zText);
+ zText = zTextNew;
+ }else{
+ zText = sqlite3_mprintf("{%s}", zCell);
+ }
+ }
+
+ sqlite3_result_text(ctx, zText, -1, sqlite3_free);
+}
+
+static void rtreedepth(sqlite3_context *ctx, int nArg, sqlite3_value **apArg){
+ if( sqlite3_value_type(apArg[0])!=SQLITE_BLOB
+ || sqlite3_value_bytes(apArg[0])<2
+ ){
+ sqlite3_result_error(ctx, "Invalid argument to rtreedepth()", -1);
+ }else{
+ u8 *zBlob = (u8 *)sqlite3_value_blob(apArg[0]);
+ sqlite3_result_int(ctx, readInt16(zBlob));
+ }
+}
+
+/*
+** Register the r-tree module with database handle db. This creates the
+** virtual table module "rtree" and the debugging/analysis scalar
+** function "rtreenode".
+*/
+int sqlite3RtreeInit(sqlite3 *db){
+ int rc = SQLITE_OK;
+
+ if( rc==SQLITE_OK ){
+ int utf8 = SQLITE_UTF8;
+ rc = sqlite3_create_function(db, "rtreenode", 2, utf8, 0, rtreenode, 0, 0);
+ }
+ if( rc==SQLITE_OK ){
+ int utf8 = SQLITE_UTF8;
+ rc = sqlite3_create_function(db, "rtreedepth", 1, utf8, 0,rtreedepth, 0, 0);
+ }
+ if( rc==SQLITE_OK ){
+ void *c = (void *)RTREE_COORD_REAL32;
+ rc = sqlite3_create_module_v2(db, "rtree", &rtreeModule, c, 0);
+ }
+ if( rc==SQLITE_OK ){
+ void *c = (void *)RTREE_COORD_INT32;
+ rc = sqlite3_create_module_v2(db, "rtree_i32", &rtreeModule, c, 0);
+ }
+
+ return rc;
+}
+
+#if !SQLITE_CORE
+int sqlite3_extension_init(
+ sqlite3 *db,
+ char **pzErrMsg,
+ const sqlite3_api_routines *pApi
+){
+ SQLITE_EXTENSION_INIT2(pApi)
+ return sqlite3RtreeInit(db);
+}
+#endif
+
+#endif