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Diffstat (limited to 'ext/rtree/rtree.c')
| -rw-r--r-- | ext/rtree/rtree.c | 3285 |
1 files changed, 3285 insertions, 0 deletions
diff --git a/ext/rtree/rtree.c b/ext/rtree/rtree.c new file mode 100644 index 0000000..884482e --- /dev/null +++ b/ext/rtree/rtree.c @@ -0,0 +1,3285 @@ +/* +** 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. +*/ + +/* +** Database Format of R-Tree Tables +** -------------------------------- +** +** The data structure for a single virtual r-tree table is stored in three +** native SQLite tables declared as follows. In each case, the '%' character +** in the table name is replaced with the user-supplied name of the r-tree +** table. +** +** CREATE TABLE %_node(nodeno INTEGER PRIMARY KEY, data BLOB) +** CREATE TABLE %_parent(nodeno INTEGER PRIMARY KEY, parentnode INTEGER) +** CREATE TABLE %_rowid(rowid INTEGER PRIMARY KEY, nodeno INTEGER) +** +** The data for each node of the r-tree structure is stored in the %_node +** table. For each node that is not the root node of the r-tree, there is +** an entry in the %_parent table associating the node with its parent. +** And for each row of data in the table, there is an entry in the %_rowid +** table that maps from the entries rowid to the id of the node that it +** is stored on. +** +** The root node of an r-tree always exists, even if the r-tree table is +** empty. The nodeno of the root node is always 1. All other nodes in the +** table must be the same size as the root node. The content of each node +** is formatted as follows: +** +** 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. +*/ + +#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 + +#if !defined(NDEBUG) && !defined(SQLITE_DEBUG) +# define NDEBUG 1 +#endif + +#ifndef SQLITE_CORE + #include "sqlite3ext.h" + SQLITE_EXTENSION_INIT1 +#else + #include "sqlite3.h" +#endif + +#include <string.h> +#include <assert.h> + +#ifndef SQLITE_AMALGAMATION +#include "sqlite3rtree.h" +typedef sqlite3_int64 i64; +typedef unsigned char u8; +typedef unsigned int u32; +#endif + +/* The following macro is used to suppress compiler warnings. +*/ +#ifndef UNUSED_PARAMETER +# define UNUSED_PARAMETER(x) (void)(x) +#endif + +typedef struct Rtree Rtree; +typedef struct RtreeCursor RtreeCursor; +typedef struct RtreeNode RtreeNode; +typedef struct RtreeCell RtreeCell; +typedef struct RtreeConstraint RtreeConstraint; +typedef struct RtreeMatchArg RtreeMatchArg; +typedef struct RtreeGeomCallback RtreeGeomCallback; +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 + +/* +** The smallest possible node-size is (512-64)==448 bytes. And the largest +** supported cell size is 48 bytes (8 byte rowid + ten 4 byte coordinates). +** Therefore all non-root nodes must contain at least 3 entries. Since +** 2^40 is greater than 2^64, an r-tree structure always has a depth of +** 40 or less. +*/ +#define RTREE_MAX_DEPTH 40 + +/* +** 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. */ + int (*xGeom)(sqlite3_rtree_geometry *, int, double *, int *); + sqlite3_rtree_geometry *pGeom; /* Constraint callback argument for a MATCH */ +}; + +/* 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 +#define RTREE_MATCH 0x46 + +/* +** An rtree structure node. +*/ +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]; +}; + + +/* +** Value for the first field of every RtreeMatchArg object. The MATCH +** operator tests that the first field of a blob operand matches this +** value to avoid operating on invalid blobs (which could cause a segfault). +*/ +#define RTREE_GEOMETRY_MAGIC 0x891245AB + +/* +** An instance of this structure must be supplied as a blob argument to +** the right-hand-side of an SQL MATCH operator used to constrain an +** r-tree query. +*/ +struct RtreeMatchArg { + u32 magic; /* Always RTREE_GEOMETRY_MAGIC */ + int (*xGeom)(sqlite3_rtree_geometry *, int, double *, int *); + void *pContext; + int nParam; + double aParam[1]; +}; + +/* +** When a geometry callback is created (see sqlite3_rtree_geometry_callback), +** a single instance of the following structure is allocated. It is used +** as the context for the user-function created by by s_r_g_c(). The object +** is eventually deleted by the destructor mechanism provided by +** sqlite3_create_function_v2() (which is called by s_r_g_c() to create +** the geometry callback function). +*/ +struct RtreeGeomCallback { + int (*xGeom)(sqlite3_rtree_geometry *, int, double *, int *); + void *pContext; +}; + +#ifndef MAX +# define MAX(x,y) ((x) < (y) ? (y) : (x)) +#endif +#ifndef MIN +# define MIN(x,y) ((x) > (y) ? (y) : (x)) +#endif + +/* +** 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){ + 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; + 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){ + 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){ + RtreeNode *pNode; + pNode = (RtreeNode *)sqlite3_malloc(sizeof(RtreeNode) + pRtree->iNodeSize); + if( pNode ){ + memset(pNode, 0, sizeof(RtreeNode) + pRtree->iNodeSize); + 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; + int rc2 = SQLITE_OK; + 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 ){ + nodeReference(pParent); + pNode->pParent = pParent; + } + pNode->nRef++; + *ppNode = pNode; + return SQLITE_OK; + } + + 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); + if( pRtree->iNodeSize==sqlite3_column_bytes(pRtree->pReadNode, 0) ){ + pNode = (RtreeNode *)sqlite3_malloc(sizeof(RtreeNode)+pRtree->iNodeSize); + if( !pNode ){ + rc2 = SQLITE_NOMEM; + }else{ + pNode->pParent = pParent; + pNode->zData = (u8 *)&pNode[1]; + pNode->nRef = 1; + pNode->iNode = iNode; + pNode->isDirty = 0; + pNode->pNext = 0; + memcpy(pNode->zData, zBlob, pRtree->iNodeSize); + nodeReference(pParent); + } + } + } + rc = sqlite3_reset(pRtree->pReadNode); + if( rc==SQLITE_OK ) rc = rc2; + + /* If the root node was just loaded, set pRtree->iDepth to the height + ** of the r-tree structure. A height of zero means all data is stored on + ** the root node. A height of one means the children of the root node + ** are the leaves, and so on. If the depth as specified on the root node + ** is greater than RTREE_MAX_DEPTH, the r-tree structure must be corrupt. + */ + if( pNode && iNode==1 ){ + pRtree->iDepth = readInt16(pNode->zData); + if( pRtree->iDepth>RTREE_MAX_DEPTH ){ + rc = SQLITE_CORRUPT_VTAB; + } + } + + /* If no error has occurred so far, check if the "number of entries" + ** field on the node is too large. If so, set the return code to + ** SQLITE_CORRUPT_VTAB. + */ + if( pNode && rc==SQLITE_OK ){ + if( NCELL(pNode)>((pRtree->iNodeSize-4)/pRtree->nBytesPerCell) ){ + rc = SQLITE_CORRUPT_VTAB; + } + } + + if( rc==SQLITE_OK ){ + if( pNode!=0 ){ + nodeHashInsert(pRtree, pNode); + }else{ + rc = SQLITE_CORRUPT_VTAB; + } + *ppNode = pNode; + }else{ + sqlite3_free(pNode); + *ppNode = 0; + } + + 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 +); + +/* +** 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); +} + +/* +** 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); +} + +/* +** 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; +} + + +/* +** Free the RtreeCursor.aConstraint[] array and its contents. +*/ +static void freeCursorConstraints(RtreeCursor *pCsr){ + if( pCsr->aConstraint ){ + int i; /* Used to iterate through constraint array */ + for(i=0; i<pCsr->nConstraint; i++){ + sqlite3_rtree_geometry *pGeom = pCsr->aConstraint[i].pGeom; + if( pGeom ){ + if( pGeom->xDelUser ) pGeom->xDelUser(pGeom->pUser); + sqlite3_free(pGeom); + } + } + sqlite3_free(pCsr->aConstraint); + pCsr->aConstraint = 0; + } +} + +/* +** Rtree virtual table module xClose method. +*/ +static int rtreeClose(sqlite3_vtab_cursor *cur){ + Rtree *pRtree = (Rtree *)(cur->pVtab); + int rc; + RtreeCursor *pCsr = (RtreeCursor *)cur; + freeCursorConstraints(pCsr); + 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); +} + +/* +** The r-tree constraint passed as the second argument to this function is +** guaranteed to be a MATCH constraint. +*/ +static int testRtreeGeom( + Rtree *pRtree, /* R-Tree object */ + RtreeConstraint *pConstraint, /* MATCH constraint to test */ + RtreeCell *pCell, /* Cell to test */ + int *pbRes /* OUT: Test result */ +){ + int i; + double aCoord[RTREE_MAX_DIMENSIONS*2]; + int nCoord = pRtree->nDim*2; + + assert( pConstraint->op==RTREE_MATCH ); + assert( pConstraint->pGeom ); + + for(i=0; i<nCoord; i++){ + aCoord[i] = DCOORD(pCell->aCoord[i]); + } + return pConstraint->xGeom(pConstraint->pGeom, nCoord, aCoord, pbRes); +} + +/* +** Cursor pCursor currently points to a cell in a non-leaf page. +** Set *pbEof to true if the sub-tree headed by the cell is filtered +** (excluded) by the constraints in the pCursor->aConstraint[] +** array, or false otherwise. +** +** Return SQLITE_OK if successful or an SQLite error code if an error +** occurs within a geometry callback. +*/ +static int testRtreeCell(Rtree *pRtree, RtreeCursor *pCursor, int *pbEof){ + RtreeCell cell; + int ii; + int bRes = 0; + int rc = SQLITE_OK; + + 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 || p->op==RTREE_MATCH + ); + + 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; + + default: { + assert( p->op==RTREE_MATCH ); + rc = testRtreeGeom(pRtree, p, &cell, &bRes); + bRes = !bRes; + break; + } + } + } + + *pbEof = bRes; + return rc; +} + +/* +** Test if the cell that cursor pCursor currently points to +** would be filtered (excluded) by the constraints in the +** pCursor->aConstraint[] array. If so, set *pbEof to true before +** returning. If the cell is not filtered (excluded) by the constraints, +** set pbEof to zero. +** +** Return SQLITE_OK if successful or an SQLite error code if an error +** occurs within a geometry callback. +** +** This function assumes that the cell is part of a leaf node. +*/ +static int testRtreeEntry(Rtree *pRtree, RtreeCursor *pCursor, int *pbEof){ + RtreeCell cell; + int ii; + *pbEof = 0; + + 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 || p->op==RTREE_MATCH + ); + 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; + default: { + int rc; + assert( p->op==RTREE_MATCH ); + rc = testRtreeGeom(pRtree, p, &cell, &res); + if( rc!=SQLITE_OK ){ + return rc; + } + break; + } + } + + if( !res ){ + *pbEof = 1; + return SQLITE_OK; + } + } + + return SQLITE_OK; +} + +/* +** 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 ){ + rc = testRtreeEntry(pRtree, pCursor, &isEof); + }else{ + rc = testRtreeCell(pRtree, pCursor, &isEof); + } + if( rc!=SQLITE_OK || isEof || iHeight==0 ){ + goto descend_to_cell_out; + } + + iRowid = nodeGetRowid(pRtree, pCursor->pNode, pCursor->iCell); + rc = nodeAcquire(pRtree, iRowid, pCursor->pNode, &pChild); + if( rc!=SQLITE_OK ){ + goto descend_to_cell_out; + } + + 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 ){ + goto descend_to_cell_out; + } + } + + if( isEof ){ + assert( pCursor->pNode==pChild ); + nodeReference(pSavedNode); + nodeRelease(pRtree, pChild); + pCursor->pNode = pSavedNode; + pCursor->iCell = iSavedCell; + } + +descend_to_cell_out: + *pEof = isEof; + return rc; +} + +/* +** 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 *piIndex +){ + int ii; + int nCell = NCELL(pNode); + for(ii=0; ii<nCell; ii++){ + if( nodeGetRowid(pRtree, pNode, ii)==iRowid ){ + *piIndex = ii; + return SQLITE_OK; + } + } + return SQLITE_CORRUPT_VTAB; +} + +/* +** 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, int *piIndex){ + RtreeNode *pParent = pNode->pParent; + if( pParent ){ + return nodeRowidIndex(pRtree, pParent, pNode->iNode, piIndex); + } + *piIndex = -1; + return SQLITE_OK; +} + +/* +** 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; + + /* RtreeCursor.pNode must not be NULL. If is is NULL, then this cursor is + ** already at EOF. It is against the rules to call the xNext() method of + ** a cursor that has already reached EOF. + */ + assert( pCsr->pNode ); + + 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{ + /* 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; + rc = nodeParentIndex(pRtree, pNode, &pCsr->iCell); + if( rc!=SQLITE_OK ){ + return rc; + } + 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; +} + +/* +** This function is called to configure the RtreeConstraint object passed +** as the second argument for a MATCH constraint. The value passed as the +** first argument to this function is the right-hand operand to the MATCH +** operator. +*/ +static int deserializeGeometry(sqlite3_value *pValue, RtreeConstraint *pCons){ + RtreeMatchArg *p; + sqlite3_rtree_geometry *pGeom; + int nBlob; + + /* Check that value is actually a blob. */ + if( !sqlite3_value_type(pValue)==SQLITE_BLOB ) return SQLITE_ERROR; + + /* Check that the blob is roughly the right size. */ + nBlob = sqlite3_value_bytes(pValue); + if( nBlob<(int)sizeof(RtreeMatchArg) + || ((nBlob-sizeof(RtreeMatchArg))%sizeof(double))!=0 + ){ + return SQLITE_ERROR; + } + + pGeom = (sqlite3_rtree_geometry *)sqlite3_malloc( + sizeof(sqlite3_rtree_geometry) + nBlob + ); + if( !pGeom ) return SQLITE_NOMEM; + memset(pGeom, 0, sizeof(sqlite3_rtree_geometry)); + p = (RtreeMatchArg *)&pGeom[1]; + + memcpy(p, sqlite3_value_blob(pValue), nBlob); + if( p->magic!=RTREE_GEOMETRY_MAGIC + || nBlob!=(int)(sizeof(RtreeMatchArg) + (p->nParam-1)*sizeof(double)) + ){ + sqlite3_free(pGeom); + return SQLITE_ERROR; + } + + pGeom->pContext = p->pContext; + pGeom->nParam = p->nParam; + pGeom->aParam = p->aParam; + + pCons->xGeom = p->xGeom; + pCons->pGeom = pGeom; + return SQLITE_OK; +} + +/* +** 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); + + freeCursorConstraints(pCsr); + 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 ){ + assert( rc==SQLITE_OK ); + rc = nodeRowidIndex(pRtree, pLeaf, iRowid, &pCsr->iCell); + } + }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{ + memset(pCsr->aConstraint, 0, sizeof(RtreeConstraint)*argc); + assert( (idxStr==0 && argc==0) + || (idxStr && (int)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'; + if( p->op==RTREE_MATCH ){ + /* A MATCH operator. The right-hand-side must be a blob that + ** can be cast into an RtreeMatchArg object. One created using + ** an sqlite3_rtree_geometry_callback() SQL user function. + */ + rc = deserializeGeometry(argv[ii], p); + if( rc!=SQLITE_OK ){ + break; + } + }else{ + 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 or full-table scan. +** ------------------------------------------------ +** +** If strategy 1 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') +** MATCH 0x46 ('F') +** ---------------------- +** +** 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; + + int iIdx = 0; + char zIdxStr[RTREE_MAX_DIMENSIONS*8+1]; + memset(zIdxStr, 0, sizeof(zIdxStr)); + UNUSED_PARAMETER(tab); + + assert( pIdxInfo->idxStr==0 ); + for(ii=0; ii<pIdxInfo->nConstraint && iIdx<(int)(sizeof(zIdxStr)-1); 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 || p->op==SQLITE_INDEX_CONSTRAINT_MATCH) ){ + u8 op; + 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; + default: + assert( p->op==SQLITE_INDEX_CONSTRAINT_MATCH ); + op = RTREE_MATCH; + break; + } + zIdxStr[iIdx++] = op; + zIdxStr[iIdx++] = p->iColumn - 1 + 'a'; + 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 = (float)(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 += (float)(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 VARIANT_RSTARTREE_CHOOSESUBTREE + if( ii!=iExclude ) +#else + assert( iExclude==-1 ); + UNUSED_PARAMETER(iExclude); +#endif + { + 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 * (float)(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 +){ + double before; + double after; + before = cellOverlap(pRtree, p, aCell, nCell, iExclude); + cellUnion(pRtree, p, pInsert); + after = cellOverlap(pRtree, p, aCell, nCell, iExclude); + return (float)(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 = 0; + + float fMinGrowth = 0.0; + float fMinArea = 0.0; +#if VARIANT_RSTARTREE_CHOOSESUBTREE + float fMinOverlap = 0.0; + float overlap; +#endif + + 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++){ + int bBest = 0; + float growth; + float area; + 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); + }else{ + overlap = 0.0; + } + if( (iCell==0) + || (overlap<fMinOverlap) + || (overlap==fMinOverlap && growth<fMinGrowth) + || (overlap==fMinOverlap && growth==fMinGrowth && area<fMinArea) + ){ + bBest = 1; + fMinOverlap = overlap; + } +#else + if( iCell==0||growth<fMinGrowth||(growth==fMinGrowth && area<fMinArea) ){ + bBest = 1; + } +#endif + if( bBest ){ + 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 int 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 ){ + RtreeNode *pParent = p->pParent; + RtreeCell cell; + int iCell; + + if( nodeParentIndex(pRtree, p, &iCell) ){ + return SQLITE_CORRUPT_VTAB; + } + + nodeGetCell(pRtree, pParent, iCell, &cell); + if( !cellContains(pRtree, &cell, pCell) ){ + cellUnion(pRtree, &cell, pCell); + nodeOverwriteCell(pRtree, pParent, &cell, iCell); + } + + p = pParent; + } + return SQLITE_OK; +} + +/* +** 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 = DCOORD(aCell[0].aCoord[i*2]); + float x2 = DCOORD(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 = DCOORD(aCell[jj].aCoord[i*2]); + float right = DCOORD(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 = 0; + int iBestSplit = 0; + float fBestMargin = 0.0; + + 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 = 0.0; + float fBestArea = 0.0; + int iBestLeft = 0; + 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); + if( !aiUsed ){ + return SQLITE_NOMEM; + } + 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); + pLeft = nodeNew(pRtree, pNode); + pRtree->iDepth++; + pNode->isDirty = 1; + writeInt16(pNode->zData, pRtree->iDepth); + }else{ + pLeft = pNode; + pRight = nodeNew(pRtree, pLeft->pParent); + 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 by calling + ** nodeWrite(). Node pRight always needs a node number, as it was created + ** by nodeNew() above. But node pLeft sometimes already has a node number. + ** In this case avoid the all to nodeWrite(). + */ + if( 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; + rc = nodeParentIndex(pRtree, pLeft, &iCell); + if( rc==SQLITE_OK ){ + nodeOverwriteCell(pRtree, pParent, &leftbbox, iCell); + rc = AdjustTree(pRtree, pParent, &leftbbox); + } + if( rc!=SQLITE_OK ){ + goto splitnode_out; + } + } + 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; +} + +/* +** If node pLeaf is not the root of the r-tree and its pParent pointer is +** still NULL, load all ancestor nodes of pLeaf into memory and populate +** the pLeaf->pParent chain all the way up to the root node. +** +** This operation is required when a row is deleted (or updated - an update +** is implemented as a delete followed by an insert). SQLite provides the +** rowid of the row to delete, which can be used to find the leaf on which +** the entry resides (argument pLeaf). Once the leaf is located, this +** function is called to determine its ancestry. +*/ +static int fixLeafParent(Rtree *pRtree, RtreeNode *pLeaf){ + int rc = SQLITE_OK; + RtreeNode *pChild = pLeaf; + while( rc==SQLITE_OK && pChild->iNode!=1 && pChild->pParent==0 ){ + int rc2 = SQLITE_OK; /* sqlite3_reset() return code */ + sqlite3_bind_int64(pRtree->pReadParent, 1, pChild->iNode); + rc = sqlite3_step(pRtree->pReadParent); + if( rc==SQLITE_ROW ){ + RtreeNode *pTest; /* Used to test for reference loops */ + i64 iNode; /* Node number of parent node */ + + /* Before setting pChild->pParent, test that we are not creating a + ** loop of references (as we would if, say, pChild==pParent). We don't + ** want to do this as it leads to a memory leak when trying to delete + ** the referenced counted node structures. + */ + iNode = sqlite3_column_int64(pRtree->pReadParent, 0); + for(pTest=pLeaf; pTest && pTest->iNode!=iNode; pTest=pTest->pParent); + if( !pTest ){ + rc2 = nodeAcquire(pRtree, iNode, 0, &pChild->pParent); + } + } + rc = sqlite3_reset(pRtree->pReadParent); + if( rc==SQLITE_OK ) rc = rc2; + if( rc==SQLITE_OK && !pChild->pParent ) rc = SQLITE_CORRUPT_VTAB; + pChild = pChild->pParent; + } + return rc; +} + +static int deleteCell(Rtree *, RtreeNode *, int, int); + +static int removeNode(Rtree *pRtree, RtreeNode *pNode, int iHeight){ + int rc; + int rc2; + RtreeNode *pParent = 0; + int iCell; + + assert( pNode->nRef==1 ); + + /* Remove the entry in the parent cell. */ + rc = nodeParentIndex(pRtree, pNode, &iCell); + if( rc==SQLITE_OK ){ + pParent = pNode->pParent; + pNode->pParent = 0; + rc = deleteCell(pRtree, pParent, iCell, iHeight+1); + } + rc2 = nodeRelease(pRtree, pParent); + if( rc==SQLITE_OK ){ + rc = rc2; + } + if( rc!=SQLITE_OK ){ + 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 int fixBoundingBox(Rtree *pRtree, RtreeNode *pNode){ + RtreeNode *pParent = pNode->pParent; + int rc = SQLITE_OK; + 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; + rc = nodeParentIndex(pRtree, pNode, &ii); + if( rc==SQLITE_OK ){ + nodeOverwriteCell(pRtree, pParent, &box, ii); + rc = fixBoundingBox(pRtree, pParent); + } + } + return rc; +} + +/* +** 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){ + RtreeNode *pParent; + 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. + */ + pParent = pNode->pParent; + assert( pParent || pNode->iNode==1 ); + if( pParent ){ + if( NCELL(pNode)<RTREE_MINCELLS(pRtree) ){ + rc = removeNode(pRtree, pNode, iHeight); + }else{ + rc = 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] += (float)DCOORD(aCell[ii].aCoord[iDim*2]); + aCenterCoord[iDim] += (float)DCOORD(aCell[ii].aCoord[iDim*2+1]); + } + } + for(iDim=0; iDim<pRtree->nDim; iDim++){ + aCenterCoord[iDim] = (float)(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 = (float)(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 ){ + rc = 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{ + rc = AdjustTree(pRtree, pNode, pCell); + if( rc==SQLITE_OK ){ + 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, (int)pNode->iNode, &pInsert); + if( rc==SQLITE_OK ){ + int rc2; + rc = rtreeInsertCell(pRtree, pInsert, &cell, (int)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; +} + +/* +** Remove the entry with rowid=iDelete from the r-tree structure. +*/ +static int rtreeDeleteRowid(Rtree *pRtree, sqlite3_int64 iDelete){ + int rc; /* Return code */ + RtreeNode *pLeaf; /* Leaf node containing record iDelete */ + int iCell; /* Index of iDelete cell in pLeaf */ + RtreeNode *pRoot; /* Root node of rtree structure */ + + + /* 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 ){ + rc = findLeafNode(pRtree, iDelete, &pLeaf); + } + + /* Delete the cell in question from the leaf node. */ + if( rc==SQLITE_OK ){ + int rc2; + rc = nodeRowidIndex(pRtree, pLeaf, iDelete, &iCell); + if( rc==SQLITE_OK ){ + 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 && NCELL(pRoot)==1 ){ + int rc2; + 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); + } + rc2 = nodeRelease(pRtree, pChild); + if( rc==SQLITE_OK ) rc = rc2; + 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); + } + + return rc; +} + +/* +** The xUpdate method for rtree module virtual tables. +*/ +static int rtreeUpdate( + sqlite3_vtab *pVtab, + int nData, + sqlite3_value **azData, + sqlite_int64 *pRowid +){ + Rtree *pRtree = (Rtree *)pVtab; + int rc = SQLITE_OK; + RtreeCell cell; /* New cell to insert if nData>1 */ + int bHaveRowid = 0; /* Set to 1 after new rowid is determined */ + + rtreeReference(pRtree); + assert(nData>=1); + + /* Constraint handling. A write operation on an r-tree table may return + ** SQLITE_CONSTRAINT for two reasons: + ** + ** 1. A duplicate rowid value, or + ** 2. The supplied data violates the "x2>=x1" constraint. + ** + ** In the first case, if the conflict-handling mode is REPLACE, then + ** the conflicting row can be removed before proceeding. In the second + ** case, SQLITE_CONSTRAINT must be returned regardless of the + ** conflict-handling mode specified by the user. + */ + if( nData>1 ){ + int ii; + + /* 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; + } + } + } + + /* If a rowid value was supplied, check if it is already present in + ** the table. If so, the constraint has failed. */ + if( sqlite3_value_type(azData[2])!=SQLITE_NULL ){ + cell.iRowid = sqlite3_value_int64(azData[2]); + if( sqlite3_value_type(azData[0])==SQLITE_NULL + || sqlite3_value_int64(azData[0])!=cell.iRowid + ){ + int steprc; + sqlite3_bind_int64(pRtree->pReadRowid, 1, cell.iRowid); + steprc = sqlite3_step(pRtree->pReadRowid); + rc = sqlite3_reset(pRtree->pReadRowid); + if( SQLITE_ROW==steprc ){ + if( sqlite3_vtab_on_conflict(pRtree->db)==SQLITE_REPLACE ){ + rc = rtreeDeleteRowid(pRtree, cell.iRowid); + }else{ + rc = SQLITE_CONSTRAINT; + goto constraint; + } + } + } + bHaveRowid = 1; + } + } + + /* 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 ){ + rc = rtreeDeleteRowid(pRtree, sqlite3_value_int64(azData[0])); + } + + /* 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 the new record into the r-tree */ + RtreeNode *pLeaf; + + /* Figure out the rowid of the new row. */ + if( bHaveRowid==0 ){ + rc = newRowid(pRtree, &cell.iRowid); + } + *pRowid = cell.iRowid; + + 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 */ + 0, /* xSavepoint */ + 0, /* xRelease */ + 0 /* xRollbackTo */ +}; + +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; +} + +/* +** The second argument to this function contains the text of an SQL statement +** that returns a single integer value. The statement is compiled and executed +** using database connection db. If successful, the integer value returned +** is written to *piVal and SQLITE_OK returned. Otherwise, an SQLite error +** code is returned and the value of *piVal after returning is not defined. +*/ +static int getIntFromStmt(sqlite3 *db, const char *zSql, int *piVal){ + int rc = SQLITE_NOMEM; + if( zSql ){ + sqlite3_stmt *pStmt = 0; + rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0); + if( rc==SQLITE_OK ){ + if( SQLITE_ROW==sqlite3_step(pStmt) ){ + *piVal = sqlite3_column_int(pStmt, 0); + } + rc = sqlite3_finalize(pStmt); + } + } + return rc; +} + +/* +** This function is called from within the xConnect() or xCreate() method to +** determine the node-size used by the rtree table being created or connected +** to. If successful, pRtree->iNodeSize is populated and SQLITE_OK returned. +** Otherwise, an SQLite error code is returned. +** +** If this function is being called as part of an xConnect(), then the rtree +** table already exists. In this case the node-size is determined by inspecting +** the root node of the tree. +** +** Otherwise, for an xCreate(), use 64 bytes less than the database page-size. +** This ensures that each node is stored on a single database page. If the +** database page-size is so large that more than RTREE_MAXCELLS entries +** would fit in a single node, use a smaller node-size. +*/ +static int getNodeSize( + sqlite3 *db, /* Database handle */ + Rtree *pRtree, /* Rtree handle */ + int isCreate /* True for xCreate, false for xConnect */ +){ + int rc; + char *zSql; + if( isCreate ){ + int iPageSize = 0; + zSql = sqlite3_mprintf("PRAGMA %Q.page_size", pRtree->zDb); + rc = getIntFromStmt(db, zSql, &iPageSize); + if( rc==SQLITE_OK ){ + pRtree->iNodeSize = iPageSize-64; + if( (4+pRtree->nBytesPerCell*RTREE_MAXCELLS)<pRtree->iNodeSize ){ + pRtree->iNodeSize = 4+pRtree->nBytesPerCell*RTREE_MAXCELLS; + } + } + }else{ + zSql = sqlite3_mprintf( + "SELECT length(data) FROM '%q'.'%q_node' WHERE nodeno = 1", + pRtree->zDb, pRtree->zName + ); + rc = getIntFromStmt(db, zSql, &pRtree->iNodeSize); + } + + sqlite3_free(zSql); + return rc; +} + +/* +** 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, /* One of the RTREE_COORD_* constants */ + 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 rc = SQLITE_OK; + Rtree *pRtree; + int nDb; /* Length of string argv[1] */ + int nName; /* Length of string argv[2] */ + int eCoordType = (pAux ? RTREE_COORD_INT32 : RTREE_COORD_REAL32); + + 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; + } + + sqlite3_vtab_config(db, SQLITE_VTAB_CONSTRAINT_SUPPORT, 1); + + /* 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. */ + rc = getNodeSize(db, pRtree, isCreate); + + /* 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==SQLITE_OK ){ + 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 ){ + rc = SQLITE_NOMEM; + }else if( SQLITE_OK!=(rc = sqlite3_declare_vtab(db, zSql)) ){ + *pzErr = sqlite3_mprintf("%s", sqlite3_errmsg(db)); + } + 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; + + UNUSED_PARAMETER(nArg); + 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],"%lld", 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){ + UNUSED_PARAMETER(nArg); + 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){ + const int utf8 = SQLITE_UTF8; + int rc; + + rc = sqlite3_create_function(db, "rtreenode", 2, utf8, 0, rtreenode, 0, 0); + if( rc==SQLITE_OK ){ + 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; +} + +/* +** A version of sqlite3_free() that can be used as a callback. This is used +** in two places - as the destructor for the blob value returned by the +** invocation of a geometry function, and as the destructor for the geometry +** functions themselves. +*/ +static void doSqlite3Free(void *p){ + sqlite3_free(p); +} + +/* +** Each call to sqlite3_rtree_geometry_callback() creates an ordinary SQLite +** scalar user function. This C function is the callback used for all such +** registered SQL functions. +** +** The scalar user functions return a blob that is interpreted by r-tree +** table MATCH operators. +*/ +static void geomCallback(sqlite3_context *ctx, int nArg, sqlite3_value **aArg){ + RtreeGeomCallback *pGeomCtx = (RtreeGeomCallback *)sqlite3_user_data(ctx); + RtreeMatchArg *pBlob; + int nBlob; + + nBlob = sizeof(RtreeMatchArg) + (nArg-1)*sizeof(double); + pBlob = (RtreeMatchArg *)sqlite3_malloc(nBlob); + if( !pBlob ){ + sqlite3_result_error_nomem(ctx); + }else{ + int i; + pBlob->magic = RTREE_GEOMETRY_MAGIC; + pBlob->xGeom = pGeomCtx->xGeom; + pBlob->pContext = pGeomCtx->pContext; + pBlob->nParam = nArg; + for(i=0; i<nArg; i++){ + pBlob->aParam[i] = sqlite3_value_double(aArg[i]); + } + sqlite3_result_blob(ctx, pBlob, nBlob, doSqlite3Free); + } +} + +/* +** Register a new geometry function for use with the r-tree MATCH operator. +*/ +int sqlite3_rtree_geometry_callback( + sqlite3 *db, + const char *zGeom, + int (*xGeom)(sqlite3_rtree_geometry *, int, double *, int *), + void *pContext +){ + RtreeGeomCallback *pGeomCtx; /* Context object for new user-function */ + + /* Allocate and populate the context object. */ + pGeomCtx = (RtreeGeomCallback *)sqlite3_malloc(sizeof(RtreeGeomCallback)); + if( !pGeomCtx ) return SQLITE_NOMEM; + pGeomCtx->xGeom = xGeom; + pGeomCtx->pContext = pContext; + + /* Create the new user-function. Register a destructor function to delete + ** the context object when it is no longer required. */ + return sqlite3_create_function_v2(db, zGeom, -1, SQLITE_ANY, + (void *)pGeomCtx, geomCallback, 0, 0, doSqlite3Free + ); +} + +#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 |