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Overview
Comment:The BTree code compiles and links now, but it does not work yet. (CVS 226)
Downloads: Tarball | ZIP archive
Timelines: family | ancestors | descendants | both | trunk
Files: files | file ages | folders
SHA1: b31c49021c260a67b7848bc077b75a7146e31c71
User & Date: drh 2001-06-22 19:15:00.000
Context
2001-06-23
11:36
Fix a bug in pager.c introduced in the previous delta. (CVS 227) (check-in: f4df666403 user: drh tags: trunk)
2001-06-22
19:15
The BTree code compiles and links now, but it does not work yet. (CVS 226) (check-in: b31c49021c user: drh tags: trunk)
2001-06-10
19:56
All BTree code is in place. Now we just have to make it work. (CVS 225) (check-in: d4be4709ee user: drh tags: trunk)
Changes
Unified Diff Ignore Whitespace Patch
Changes to Makefile.in.
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# The library that programs using readline() must link against.
#
LIBREADLINE = @TARGET_READLINE_LIBS@

# Object files for the SQLite library.
#
LIBOBJ = build.o dbbe.o dbbegdbm.o dbbemem.o delete.o expr.o insert.o \
         main.o pager.o parse.o printf.o random.o select.o table.o \
         tokenize.o update.o util.o vdbe.o where.o tclsqlite.o

# All of the source code files.
#
SRC = \

  $(TOP)/src/build.c \
  $(TOP)/src/dbbe.c \
  $(TOP)/src/dbbe.h \
  $(TOP)/src/dbbegdbm.c \
  $(TOP)/src/dbbemem.c \
  $(TOP)/src/delete.c \
  $(TOP)/src/expr.c \







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# The library that programs using readline() must link against.
#
LIBREADLINE = @TARGET_READLINE_LIBS@

# Object files for the SQLite library.
#
LIBOBJ = btree.o build.o dbbe.o dbbegdbm.o dbbemem.o delete.o expr.o insert.o \
         main.o pager.o parse.o printf.o random.o select.o table.o \
         tokenize.o update.o util.o vdbe.o where.o tclsqlite.o

# All of the source code files.
#
SRC = \
  $(TOP)/src/btree.c \
  $(TOP)/src/build.c \
  $(TOP)/src/dbbe.c \
  $(TOP)/src/dbbe.h \
  $(TOP)/src/dbbegdbm.c \
  $(TOP)/src/dbbemem.c \
  $(TOP)/src/delete.c \
  $(TOP)/src/expr.c \
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  $(TOP)/src/vdbe.h \
  $(TOP)/src/where.c

# Source code to the test files.
#
TESTSRC = \
  $(TOP)/src/test1.c \
  $(TOP)/src/test2.c


# This is the default Makefile target.  The objects listed here
# are what get build when you type just "make" with no arguments.
#
all:	sqlite.h libsqlite.a sqlite 

# Generate the file "last_change" which contains the date of change







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  $(TOP)/src/vdbe.h \
  $(TOP)/src/where.c

# Source code to the test files.
#
TESTSRC = \
  $(TOP)/src/test1.c \
  $(TOP)/src/test2.c \
  $(TOP)/src/test3.c

# This is the default Makefile target.  The objects listed here
# are what get build when you type just "make" with no arguments.
#
all:	sqlite.h libsqlite.a sqlite 

# Generate the file "last_change" which contains the date of change
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	cp $(TOP)/tool/lempar.c .

# Header files used by all library source files.
#
HDR = \
   sqlite.h  \
   $(TOP)/src/sqliteInt.h  \

   $(TOP)/src/dbbe.h  \

   $(TOP)/src/vdbe.h  \
   parse.h




build.o:	$(TOP)/src/build.c $(HDR)
	$(TCC) $(GDBM_FLAGS) -c $(TOP)/src/build.c

dbbe.o:	$(TOP)/src/dbbe.c $(HDR)
	$(TCC) $(GDBM_FLAGS) -c $(TOP)/src/dbbe.c

dbbegdbm.o:	$(TOP)/src/dbbegdbm.c $(HDR)







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	cp $(TOP)/tool/lempar.c .

# Header files used by all library source files.
#
HDR = \
   sqlite.h  \
   $(TOP)/src/sqliteInt.h  \
   $(TOP)/src/btree.h \
   $(TOP)/src/dbbe.h  \
   $(TOP)/src/pager.h \
   $(TOP)/src/vdbe.h  \
   parse.h

btree.o:	$(TOP)/src/btree.c $(HDR)
	$(TCC) $(GDBM_FLAGS) -c $(TOP)/src/btree.c

build.o:	$(TOP)/src/build.c $(HDR)
	$(TCC) $(GDBM_FLAGS) -c $(TOP)/src/build.c

dbbe.o:	$(TOP)/src/dbbe.c $(HDR)
	$(TCC) $(GDBM_FLAGS) -c $(TOP)/src/dbbe.c

dbbegdbm.o:	$(TOP)/src/dbbegdbm.c $(HDR)
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tclsqlite:	$(TOP)/src/tclsqlite.c libsqlite.a
	$(TCC) $(TCL_FLAGS) -DTCLSH=1 -o tclsqlite \
		$(TOP)/src/tclsqlite.c libsqlite.a $(LIBGDBM) $(LIBTCL)

testfixture:	$(TOP)/src/tclsqlite.c libsqlite.a $(TESTSRC)
	$(TCC) $(TCL_FLAGS) -DTCLSH=1 -DSQLITE_TEST=1 -o testfixture \
		$(TESTSRC) $(TOP)/src/tclsqlite.c \
		libsqlite.a $(LIBGDBM) $(LIBTCL)

test:	testfixture sqlite
	./testfixture $(TOP)/test/all.test

sqlite.tar.gz:	
	pwd=`pwd`; cd $(TOP)/..; tar czf $$pwd/sqlite.tar.gz sqlite







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tclsqlite:	$(TOP)/src/tclsqlite.c libsqlite.a
	$(TCC) $(TCL_FLAGS) -DTCLSH=1 -o tclsqlite \
		$(TOP)/src/tclsqlite.c libsqlite.a $(LIBGDBM) $(LIBTCL)

testfixture:	$(TOP)/src/tclsqlite.c libsqlite.a $(TESTSRC)
	$(TCC) $(TCL_FLAGS) -DTCLSH=1 -DSQLITE_TEST=1 -o testfixture \
		$(TESTSRC) $(TOP)/src/tclsqlite.c $(TOP)/src/btree.c \
		libsqlite.a $(LIBGDBM) $(LIBTCL)

test:	testfixture sqlite
	./testfixture $(TOP)/test/all.test

sqlite.tar.gz:	
	pwd=`pwd`; cd $(TOP)/..; tar czf $$pwd/sqlite.tar.gz sqlite
Changes to src/btree.c.
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** Boston, MA  02111-1307, USA.
**
** Author contact information:
**   drh@hwaci.com
**   http://www.hwaci.com/drh/
**
*************************************************************************
** $Id: btree.c,v 1.12 2001/06/10 19:56:59 drh Exp $
**
** This file implements a external (disk-based) database using BTrees.
** For a detailed discussion of BTrees, refer to
**
**     Donald E. Knuth, THE ART OF COMPUTER PROGRAMMING, Volume 3:
**     "Sorting And Searching", pages 473-480. Addison-Wesley
**     Publishing Company, Reading, Massachusetts.







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** Boston, MA  02111-1307, USA.
**
** Author contact information:
**   drh@hwaci.com
**   http://www.hwaci.com/drh/
**
*************************************************************************
** $Id: btree.c,v 1.13 2001/06/22 19:15:00 drh Exp $
**
** This file implements a external (disk-based) database using BTrees.
** For a detailed discussion of BTrees, refer to
**
**     Donald E. Knuth, THE ART OF COMPUTER PROGRAMMING, Volume 3:
**     "Sorting And Searching", pages 473-480. Addison-Wesley
**     Publishing Company, Reading, Massachusetts.
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/*
** Primitive data types.  u32 must be 4 bytes and u16 must be 2 bytes.
** The uptr type must be big enough to hold a pointer.
** Change these typedefs when porting to new architectures.
*/
typedef unsigned int uptr;
typedef unsigned int u32;
typedef unsigned short int u16;
typedef unsigned char u8;







/*
** Forward declarations of structures used only in this file.
*/
typedef struct PageOne PageOne;
typedef struct MemPage MemPage;
typedef struct PageHdr PageHdr;
typedef struct Cell Cell;







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/*
** Primitive data types.  u32 must be 4 bytes and u16 must be 2 bytes.
** The uptr type must be big enough to hold a pointer.
** Change these typedefs when porting to new architectures.
*/
typedef unsigned int uptr;
/*  typedef unsigned int u32; -- already defined in sqliteInt.h */
typedef unsigned short int u16;
typedef unsigned char u8;

/*
** This macro casts a pointer to an integer.  Useful for doing
** pointer arithmetic.
*/
#define addr(X)  ((uptr)X)

/*
** Forward declarations of structures used only in this file.
*/
typedef struct PageOne PageOne;
typedef struct MemPage MemPage;
typedef struct PageHdr PageHdr;
typedef struct Cell Cell;
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** This might need to change for computer architectures that require
** and 8-byte alignment boundry for structures.
*/
#define ROUNDUP(X)  ((X+3) & ~3)

/*
** This is a magic string that appears at the beginning of every
** SQLite database in order to identify the fail as a real database.
*/
static const char zMagicHeader[] = 
   "** This file contains an SQLite 2.0 database **"
#define MAGIC_SIZE (sizeof(zMagicHeader))













/*
** The first page of the database file contains a magic header string
** to identify the file as an SQLite database file.  It also contains
** a pointer to the first free page of the file.  Page 2 contains the
** root of the principle BTree.  The file might contain other BTrees
** rooted on pages above 2.
**
** The first page also contains SQLITE_N_BTREE_META integers that
** can be used by higher-level routines.
**
** Remember that pages are numbered beginning with 1.  (See pager.c
** for additional information.)  Page 0 does not exist and a page
** number of 0 is used to mean "no such page".
*/
struct PageOne {
  char zMagic[MAGIC_SIZE]; /* String that identifies the file as a database */

  Pgno firstList;          /* First free page in a list of all free pages */
  int aMeta[SQLITE_N_BTREE_META];  /* User defined integers */
};

/*
** Each database page has a header that is an instance of this
** structure.
**







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** This might need to change for computer architectures that require
** and 8-byte alignment boundry for structures.
*/
#define ROUNDUP(X)  ((X+3) & ~3)

/*
** This is a magic string that appears at the beginning of every
** SQLite database in order to identify the file as a real database.
*/
static const char zMagicHeader[] = 
   "** This file contains an SQLite 2.0 database **";
#define MAGIC_SIZE (sizeof(zMagicHeader))

/*
** This is a magic integer also used to the integrety of the database
** file.  This integer is used in addition to the string above so that
** if the file is written on a little-endian architecture and read
** on a big-endian architectures (or vice versa) we can detect the
** problem.
**
** The number used was obtained at random and has no special
** significance.
*/
#define MAGIC 0xdae37528

/*
** The first page of the database file contains a magic header string
** to identify the file as an SQLite database file.  It also contains
** a pointer to the first free page of the file.  Page 2 contains the
** root of the principle BTree.  The file might contain other BTrees
** rooted on pages above 2.
**
** The first page also contains SQLITE_N_BTREE_META integers that
** can be used by higher-level routines.
**
** Remember that pages are numbered beginning with 1.  (See pager.c
** for additional information.)  Page 0 does not exist and a page
** number of 0 is used to mean "no such page".
*/
struct PageOne {
  char zMagic[MAGIC_SIZE]; /* String that identifies the file as a database */
  int iMagic;              /* Integer to verify correct byte order */
  Pgno freeList;           /* First free page in a list of all free pages */
  int aMeta[SQLITE_N_BTREE_META];  /* User defined integers */
};

/*
** Each database page has a header that is an instance of this
** structure.
**
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/*
** Entries on a page of the database are called "Cells".  Each Cell
** has a header and data.  This structure defines the header.  The
** key and data (collectively the "payload") follow this header on
** the database page.
**
** A definition of the complete Cell structure is given below.  The
** header for the cell must be defined separately in order to do some
** of the sizing #defines that follow.
*/
struct CellHdr {
  Pgno leftChild; /* Child page that comes before this cell */
  u16 nKey;       /* Number of bytes in the key */
  u16 iNext;      /* Index in MemPage.u.aDisk[] of next cell in sorted order */
  u32 nData;      /* Number of bytes of data */
}

/*
** The minimum size of a complete Cell.  The Cell must contain a header
** and at least 4 bytes of payload.
*/
#define MIN_CELL_SIZE  (sizeof(CellHdr)+4)

/*
** The maximum number of database entries that can be held in a single
** page of the database. 
*/
#define MX_CELL ((SQLITE_PAGE_SIZE-sizeof(PageHdr))/MIN_CELL_SIZE)

/*
** The maximum amount of data (in bytes) that can be stored locally for a
** database entry.  If the entry contains more data than this, the
** extra goes onto overflow pages.
**
** This number is chosen so that at least 4 cells will fit on every page.
*/
#define MX_LOCAL_PAYLOAD \
  ((SQLITE_PAGE_SIZE-sizeof(PageHdr))/4-(sizeof(CellHdr)+sizeof(Pgno)))








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/*
** Entries on a page of the database are called "Cells".  Each Cell
** has a header and data.  This structure defines the header.  The
** key and data (collectively the "payload") follow this header on
** the database page.
**
** A definition of the complete Cell structure is given below.  The
** header for the cell must be defined first in order to do some
** of the sizing #defines that follow.
*/
struct CellHdr {
  Pgno leftChild; /* Child page that comes before this cell */
  u16 nKey;       /* Number of bytes in the key */
  u16 iNext;      /* Index in MemPage.u.aDisk[] of next cell in sorted order */
  u32 nData;      /* Number of bytes of data */
};

/*
** The minimum size of a complete Cell.  The Cell must contain a header
** and at least 4 bytes of payload.
*/
#define MIN_CELL_SIZE  (sizeof(CellHdr)+4)

/*
** The maximum number of database entries that can be held in a single
** page of the database. 
*/
#define MX_CELL ((SQLITE_PAGE_SIZE-sizeof(PageHdr))/MIN_CELL_SIZE)

/*
** The maximum amount of payload (in bytes) that can be stored locally for
** a database entry.  If the entry contains more data than this, the
** extra goes onto overflow pages.
**
** This number is chosen so that at least 4 cells will fit on every page.
*/
#define MX_LOCAL_PAYLOAD \
  ((SQLITE_PAGE_SIZE-sizeof(PageHdr))/4-(sizeof(CellHdr)+sizeof(Pgno)))

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/*
** The number of bytes of payload that will fit on a single overflow page.
*/
#define OVERFLOW_SIZE (SQLITE_PAGE_SIZE-sizeof(Pgno))

/*
** When the key and data for a single entry in the BTree will not fit in
** the MX_LOACAL_PAYLOAD bytes of space available on the database page,
** then all extra bytes are written to a linked list of overflow pages.
** Each overflow page is an instance of the following structure.
**
** Unused pages in the database are also represented by instances of
** the OverflowPage structure.  The PageOne.freeList field is the
** page number of the first page in a linked list of unused database
** pages.







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/*
** The number of bytes of payload that will fit on a single overflow page.
*/
#define OVERFLOW_SIZE (SQLITE_PAGE_SIZE-sizeof(Pgno))

/*
** When the key and data for a single entry in the BTree will not fit in
** the MX_LOCAL_PAYLOAD bytes of space available on the database page,
** then all extra bytes are written to a linked list of overflow pages.
** Each overflow page is an instance of the following structure.
**
** Unused pages in the database are also represented by instances of
** the OverflowPage structure.  The PageOne.freeList field is the
** page number of the first page in a linked list of unused database
** pages.
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  } u;
  int isInit;                    /* True if auxiliary data is initialized */
  MemPage *pParent;              /* The parent of this page.  NULL for root */
  int nFree;                     /* Number of free bytes in u.aDisk[] */
  int nCell;                     /* Number of entries on this page */
  int isOverfull;                /* Some apCell[] points outside u.aDisk[] */
  Cell *apCell[MX_CELL+2];       /* All data entires in sorted order */
}

/*
** The in-memory image of a disk page has the auxiliary information appended
** to the end.  EXTRA_SIZE is the number of bytes of space needed to hold
** that extra information.
*/
#define EXTRA_SIZE (sizeof(MemPage)-SQLITE_PAGE_SIZE)







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  } u;
  int isInit;                    /* True if auxiliary data is initialized */
  MemPage *pParent;              /* The parent of this page.  NULL for root */
  int nFree;                     /* Number of free bytes in u.aDisk[] */
  int nCell;                     /* Number of entries on this page */
  int isOverfull;                /* Some apCell[] points outside u.aDisk[] */
  Cell *apCell[MX_CELL+2];       /* All data entires in sorted order */
};

/*
** The in-memory image of a disk page has the auxiliary information appended
** to the end.  EXTRA_SIZE is the number of bytes of space needed to hold
** that extra information.
*/
#define EXTRA_SIZE (sizeof(MemPage)-SQLITE_PAGE_SIZE)
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** MemPage.apCell[] of the entry.
*/
struct BtCursor {
  Btree *pBt;               /* The Btree to which this cursor belongs */
  BtCursor *pNext, *pPrev;  /* Forms a linked list of all cursors */
  Pgno pgnoRoot;            /* The root page of this tree */
  MemPage *pPage;           /* Page that contains the entry */
  u16 idx;                  /* Index of the entry in pPage->apCell[] */
  u8 bSkipNext;             /* sqliteBtreeNext() is no-op if true */
  u8 iMatch;                /* compare result from last sqliteBtreeMoveto() */
};

/*
** Compute the total number of bytes that a Cell needs on the main
** database page.  The number returned includes the Cell header,
** local payload storage, and the pointer to overflow pages (if
** applicable).  Additional spaced allocated on overflow pages
** is NOT included in the value returned from this routine.
*/
static int cellSize(Cell *pCell){
  int n = pCell->h.nKey + pCell->h.nData;
  if( n>MX_LOCAL_PAYLOAD ){
    n = MX_LOCAL_PAYLOAD + sizeof(Pgno);
  }else{







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** MemPage.apCell[] of the entry.
*/
struct BtCursor {
  Btree *pBt;               /* The Btree to which this cursor belongs */
  BtCursor *pNext, *pPrev;  /* Forms a linked list of all cursors */
  Pgno pgnoRoot;            /* The root page of this tree */
  MemPage *pPage;           /* Page that contains the entry */
  int idx;                  /* Index of the entry in pPage->apCell[] */
  u8 bSkipNext;             /* sqliteBtreeNext() is no-op if true */
  u8 iMatch;                /* compare result from last sqliteBtreeMoveto() */
};

/*
** Compute the total number of bytes that a Cell needs on the main
** database page.  The number returned includes the Cell header,
** local payload storage, and the pointer to overflow pages (if
** applicable).  Additional space allocated on overflow pages
** is NOT included in the value returned from this routine.
*/
static int cellSize(Cell *pCell){
  int n = pCell->h.nKey + pCell->h.nData;
  if( n>MX_LOCAL_PAYLOAD ){
    n = MX_LOCAL_PAYLOAD + sizeof(Pgno);
  }else{
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  FreeBlk *pFBlk;
  char newPage[SQLITE_PAGE_SIZE];

  pc = sizeof(PageHdr);
  pPage->u.hdr.firstCell = pc;
  memcpy(newPage, pPage->u.aDisk, pc);
  for(i=0; i<pPage->nCell; i++){
    Cell *pCell = &pPage->apCell[i];






    n = cellSize(pCell);
    pCell->h.iNext = i<pPage->nCell-1 ? pc + n : 0;
    memcpy(&newPage[pc], pCell, n);
    pPage->apCell[i] = (Cell*)&pPage->u.aDisk[pc];
    pc += n;
  }
  assert( pPage->nFree==SQLITE_PAGE_SIZE-pc );
  memcpy(pPage->u.aDisk, newPage, pc);
  pFBlk = &pPage->u.aDisk[pc];
  pFBlk->iSize = SQLITE_PAGE_SIZE - pc;
  pFBlk->iNext = 0;
  pPage->u.hdr.firstFree = pc;
  memset(&pFBlk[1], 0, SQLITE_PAGE_SIZE - pc - sizeof(FreeBlk));
}

/*







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386
387
388
389
  FreeBlk *pFBlk;
  char newPage[SQLITE_PAGE_SIZE];

  pc = sizeof(PageHdr);
  pPage->u.hdr.firstCell = pc;
  memcpy(newPage, pPage->u.aDisk, pc);
  for(i=0; i<pPage->nCell; i++){
    Cell *pCell = (Cell*)&pPage->apCell[i];

    /* This routine should never be called on an overfull page.  The
    ** following asserts verify that constraint. */
    assert( addr(pCell) > addr(pPage) );
    assert( addr(pCell) < addr(pPage) + SQLITE_PAGE_SIZE );

    n = cellSize(pCell);
    pCell->h.iNext = i<pPage->nCell-1 ? pc + n : 0;
    memcpy(&newPage[pc], pCell, n);
    pPage->apCell[i] = (Cell*)&pPage->u.aDisk[pc];
    pc += n;
  }
  assert( pPage->nFree==SQLITE_PAGE_SIZE-pc );
  memcpy(pPage->u.aDisk, newPage, pc);
  pFBlk = (FreeBlk*)&pPage->u.aDisk[pc];
  pFBlk->iSize = SQLITE_PAGE_SIZE - pc;
  pFBlk->iNext = 0;
  pPage->u.hdr.firstFree = pc;
  memset(&pFBlk[1], 0, SQLITE_PAGE_SIZE - pc - sizeof(FreeBlk));
}

/*
374
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380

381
382
383
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386

387
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389
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391
392
393
394
395
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397
398

399
400
401
402
403
404
405
406
407
** calls defragementPage() to consolidate all free space before 
** allocating the new chunk.
*/
static int allocateSpace(MemPage *pPage, int nByte){
  FreeBlk *p;
  u16 *pIdx;
  int start;


  assert( nByte==ROUNDUP(nByte) );
  if( pPage->nFree<nByte || pPage->isOverfull ) return 0;
  pIdx = &pPage->u.hdr.firstFree;
  p = (FreeBlk*)&pPage->u.aDisk[*pIdx];
  while( p->iSize<nByte ){

    if( p->iNext==0 ){
      defragmentPage(pPage);
      pIdx = &pPage->u.hdr.firstFree;
    }else{
      pIdx = &p->iNext;
    }
    p = (FreeBlk*)&pPage->u.aDisk[*pIdx];
  }
  if( p->iSize==nByte ){
    start = *pIdx;
    *pIdx = p->iNext;
  }else{

    start = *pIdx;
    FreeBlk *pNew = (FreeBlk*)&pPage->u.aDisk[start + nByte];
    pNew->iNext = p->iNext;
    pNew->iSize = p->iSize - nByte;
    *pIdx = start + nByte;
  }
  pPage->nFree -= nByte;
  return start;
}







>






>












>

|







399
400
401
402
403
404
405
406
407
408
409
410
411
412
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419
420
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423
424
425
426
427
428
429
430
431
432
433
434
435
** calls defragementPage() to consolidate all free space before 
** allocating the new chunk.
*/
static int allocateSpace(MemPage *pPage, int nByte){
  FreeBlk *p;
  u16 *pIdx;
  int start;
  int cnt = 0;

  assert( nByte==ROUNDUP(nByte) );
  if( pPage->nFree<nByte || pPage->isOverfull ) return 0;
  pIdx = &pPage->u.hdr.firstFree;
  p = (FreeBlk*)&pPage->u.aDisk[*pIdx];
  while( p->iSize<nByte ){
    assert( cnt++ < SQLITE_PAGE_SIZE/4 );
    if( p->iNext==0 ){
      defragmentPage(pPage);
      pIdx = &pPage->u.hdr.firstFree;
    }else{
      pIdx = &p->iNext;
    }
    p = (FreeBlk*)&pPage->u.aDisk[*pIdx];
  }
  if( p->iSize==nByte ){
    start = *pIdx;
    *pIdx = p->iNext;
  }else{
    FreeBlk *pNew;
    start = *pIdx;
    pNew = (FreeBlk*)&pPage->u.aDisk[start + nByte];
    pNew->iNext = p->iNext;
    pNew->iSize = p->iSize - nByte;
    *pIdx = start + nByte;
  }
  pPage->nFree -= nByte;
  return start;
}
427
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436
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441
  pIdx = &pPage->u.hdr.firstFree;
  idx = *pIdx;
  while( idx!=0 && idx<start ){
    pFBlk = (FreeBlk*)&pPage->u.aDisk[idx];
    if( idx + pFBlk->iSize == start ){
      pFBlk->iSize += size;
      if( idx + pFBlk->iSize == pFBlk->iNext ){
        pNext = (FreeBlk*)&pPage->u.aDisk[pFblk->iNext];
        pFBlk->iSize += pNext->iSize;
        pFBlk->iNext = pNext->iNext;
      }
      pPage->nFree += size;
      return;
    }
    pIdx = &pFBlk->iNext;







|







455
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  pIdx = &pPage->u.hdr.firstFree;
  idx = *pIdx;
  while( idx!=0 && idx<start ){
    pFBlk = (FreeBlk*)&pPage->u.aDisk[idx];
    if( idx + pFBlk->iSize == start ){
      pFBlk->iSize += size;
      if( idx + pFBlk->iSize == pFBlk->iNext ){
        pNext = (FreeBlk*)&pPage->u.aDisk[pFBlk->iNext];
        pFBlk->iSize += pNext->iSize;
        pFBlk->iNext = pNext->iNext;
      }
      pPage->nFree += size;
      return;
    }
    pIdx = &pFBlk->iNext;
485
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491
492
493

494
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500
  }
  if( pPage->isInit ) return SQLITE_OK;
  pPage->isInit = 1;
  pPage->nCell = 0;
  freeSpace = SQLITE_PAGE_SIZE - sizeof(PageHdr);
  idx = pPage->u.hdr.firstCell;
  while( idx!=0 ){
    if( idx>SQLITE_PAGE_SIZE-MN_CELL_SIZE ) goto page_format_error;
    if( idx<sizeof(PageHdr) ) goto page_format_error;

    pCell = (Cell*)&pPage->u.aDisk[idx];
    sz = cellSize(pCell);
    if( idx+sz > SQLITE_PAGE_SIZE ) goto page_format_error;
    freeSpace -= sz;
    pPage->apCell[pPage->nCell++] = pCell;
    idx = pCell->h.iNext;
  }







|

>







513
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  }
  if( pPage->isInit ) return SQLITE_OK;
  pPage->isInit = 1;
  pPage->nCell = 0;
  freeSpace = SQLITE_PAGE_SIZE - sizeof(PageHdr);
  idx = pPage->u.hdr.firstCell;
  while( idx!=0 ){
    if( idx>SQLITE_PAGE_SIZE-MIN_CELL_SIZE ) goto page_format_error;
    if( idx<sizeof(PageHdr) ) goto page_format_error;
    if( idx!=ROUNDUP(idx) ) goto page_format_error;
    pCell = (Cell*)&pPage->u.aDisk[idx];
    sz = cellSize(pCell);
    if( idx+sz > SQLITE_PAGE_SIZE ) goto page_format_error;
    freeSpace -= sz;
    pPage->apCell[pPage->nCell++] = pCell;
    idx = pCell->h.iNext;
  }
530
531
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536



537
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  memset(pPage, 0, SQLITE_PAGE_SIZE);
  pHdr = &pPage->u.hdr;
  pHdr->firstCell = 0;
  pHdr->firstFree = sizeof(*pHdr);
  pFBlk = (FreeBlk*)&pHdr[1];
  pFBlk->iNext = 0;
  pFBlk->iSize = SQLITE_PAGE_SIZE - sizeof(*pHdr);



}

/*
** This routine is called when the reference count for a page
** reaches zero.  We need to unref the pParent pointer when that
** happens.
*/







>
>
>







559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
  memset(pPage, 0, SQLITE_PAGE_SIZE);
  pHdr = &pPage->u.hdr;
  pHdr->firstCell = 0;
  pHdr->firstFree = sizeof(*pHdr);
  pFBlk = (FreeBlk*)&pHdr[1];
  pFBlk->iNext = 0;
  pFBlk->iSize = SQLITE_PAGE_SIZE - sizeof(*pHdr);
  pPage->nFree = pFBlk->iSize;
  pPage->nCell = 0;
  pPage->isOverfull = 0;
}

/*
** This routine is called when the reference count for a page
** reaches zero.  We need to unref the pParent pointer when that
** happens.
*/
555
556
557
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559
560
561

562
563
564
565
566
567
568
569
570
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572
573
574
575
**
** Actually, this routine just sets up the internal data structures
** for accessing the database.  We do not open the database file 
** until the first page is loaded.
*/
int sqliteBtreeOpen(const char *zFilename, int mode, Btree **ppBtree){
  Btree *pBt;


  pBt = sqliteMalloc( sizeof(*pBt) );
  if( pBt==0 ){
    **ppBtree = 0;
    return SQLITE_NOMEM;
  }
  rc = sqlitepager_open(&pBt->pPager, zFilename, 100, EXTRA_SPACE);
  if( rc!=SQLITE_OK ){
    if( pBt->pPager ) sqlitepager_close(pBt->pPager);
    sqliteFree(pBt);
    *ppBtree = 0;
    return rc;
  }
  sqlitepager_set_destructor(pBt->pPager, pageDestructor);







>



|


|







587
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595
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600
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608
**
** Actually, this routine just sets up the internal data structures
** for accessing the database.  We do not open the database file 
** until the first page is loaded.
*/
int sqliteBtreeOpen(const char *zFilename, int mode, Btree **ppBtree){
  Btree *pBt;
  int rc;

  pBt = sqliteMalloc( sizeof(*pBt) );
  if( pBt==0 ){
    *ppBtree = 0;
    return SQLITE_NOMEM;
  }
  rc = sqlitepager_open(&pBt->pPager, zFilename, 100, EXTRA_SIZE);
  if( rc!=SQLITE_OK ){
    if( pBt->pPager ) sqlitepager_close(pBt->pPager);
    sqliteFree(pBt);
    *ppBtree = 0;
    return rc;
  }
  sqlitepager_set_destructor(pBt->pPager, pageDestructor);
600
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611
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629

630
631
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633

634
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645

646
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652
** SQLITE_BUSY is returned if the database is locked.  SQLITE_NOMEM
** is returned if we run out of memory.  SQLITE_PROTOCOL is returned
** if there is a locking protocol violation.
*/
static int lockBtree(Btree *pBt){
  int rc;
  if( pBt->page1 ) return SQLITE_OK;
  rc = sqlitepager_get(pBt->pPager, 1, &pBt->page1);
  if( rc!=SQLITE_OK ) return rc;

  /* Do some checking to help insure the file we opened really is
  ** a valid database file. 
  */
  if( sqlitepager_pagecount(pBt->pPager)>0 ){
    PageOne *pP1 = pBt->page1;
    if( strcmp(pP1->zMagic1,zMagicHeader)!=0 ){
      rc = SQLITE_CORRUPT;
      goto page1_init_failed;
    }
  }
  return rc;

page1_init_failed:
  sqlitepager_unref(pBt->page1);
  pBt->page1 = 0;
  return rc;
}

/*
** Create a new database by initializing the first two pages.

*/
static int newDatabase(Btree *pBt){
  MemPage *pRoot;
  PageOne *pP1;

  if( sqlitepager_pagecount(pBt->pPager)>0 ) return SQLITE_OK;
  pP1 = pBt->page1;
  rc = sqlitepager_write(pBt->page1);
  if( rc ) return rc;
  rc = sqlitepager_get(pBt->pPager, 2, &pRoot);
  if( rc ) return rc;
  rc = sqlitepager_write(pRoot);
  if( rc ){
    sqlitepager_unref(pRoot);
    return rc;
  }
  strcpy(pP1->zMagic, zMagicHeader);

  zeroPage(pRoot);
  sqlitepager_unref(pRoot);
  return SQLITE_OK;
}

/*
** Attempt to start a new transaction.







|







|













|
>




>




|







>







633
634
635
636
637
638
639
640
641
642
643
644
645
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648
649
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651
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653
654
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656
657
658
659
660
661
662
663
664
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679
680
681
682
683
684
685
686
687
688
** SQLITE_BUSY is returned if the database is locked.  SQLITE_NOMEM
** is returned if we run out of memory.  SQLITE_PROTOCOL is returned
** if there is a locking protocol violation.
*/
static int lockBtree(Btree *pBt){
  int rc;
  if( pBt->page1 ) return SQLITE_OK;
  rc = sqlitepager_get(pBt->pPager, 1, (void**)&pBt->page1);
  if( rc!=SQLITE_OK ) return rc;

  /* Do some checking to help insure the file we opened really is
  ** a valid database file. 
  */
  if( sqlitepager_pagecount(pBt->pPager)>0 ){
    PageOne *pP1 = pBt->page1;
    if( strcmp(pP1->zMagic,zMagicHeader)!=0 || pP1->iMagic!=MAGIC ){
      rc = SQLITE_CORRUPT;
      goto page1_init_failed;
    }
  }
  return rc;

page1_init_failed:
  sqlitepager_unref(pBt->page1);
  pBt->page1 = 0;
  return rc;
}

/*
** Create a new database by initializing the first two pages of the
** file.
*/
static int newDatabase(Btree *pBt){
  MemPage *pRoot;
  PageOne *pP1;
  int rc;
  if( sqlitepager_pagecount(pBt->pPager)>0 ) return SQLITE_OK;
  pP1 = pBt->page1;
  rc = sqlitepager_write(pBt->page1);
  if( rc ) return rc;
  rc = sqlitepager_get(pBt->pPager, 2, (void**)&pRoot);
  if( rc ) return rc;
  rc = sqlitepager_write(pRoot);
  if( rc ){
    sqlitepager_unref(pRoot);
    return rc;
  }
  strcpy(pP1->zMagic, zMagicHeader);
  pP1->iMagic = MAGIC;
  zeroPage(pRoot);
  sqlitepager_unref(pRoot);
  return SQLITE_OK;
}

/*
** Attempt to start a new transaction.
660
661
662
663
664
665
666
667
668
669
670
671

672

673
674
675

676

677

678
679
680
681
682
683
684
**      sqliteBtreeDropTable()
**      sqliteBtreeInsert()
**      sqliteBtreeDelete()
**      sqliteBtreeUpdateMeta()
*/
int sqliteBtreeBeginTrans(Btree *pBt){
  int rc;
  PageOne *pP1;
  if( pBt->inTrans ) return SQLITE_ERROR;
  if( pBt->page1==0 ){
    rc = lockBtree(pBt);
    if( rc!=SQLITE_OK ) return rc;

  }

  rc = sqlitepager_write(pBt->page1);
  if( rc==SQLITE_OK ){
    pBt->inTrans = 1;

  }

  return newDatabase(pBt);

}

/*
** Remove the last reference to the database file.  This will
** remove the read lock.
*/
static void unlockBtree(Btree *pBt){







<



|
>
|
>

|
<
>

>
|
>







696
697
698
699
700
701
702

703
704
705
706
707
708
709
710
711

712
713
714
715
716
717
718
719
720
721
722
723
**      sqliteBtreeDropTable()
**      sqliteBtreeInsert()
**      sqliteBtreeDelete()
**      sqliteBtreeUpdateMeta()
*/
int sqliteBtreeBeginTrans(Btree *pBt){
  int rc;

  if( pBt->inTrans ) return SQLITE_ERROR;
  if( pBt->page1==0 ){
    rc = lockBtree(pBt);
    if( rc!=SQLITE_OK ){
      return rc;
    }
  }
  rc = sqlitepager_write(pBt->page1);
  if( rc!=SQLITE_OK ){

    return rc;
  }
  pBt->inTrans = 1;
  rc = newDatabase(pBt);
  return rc;
}

/*
** Remove the last reference to the database file.  This will
** remove the read lock.
*/
static void unlockBtree(Btree *pBt){
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
  }
  pCur = sqliteMalloc( sizeof(*pCur) );
  if( pCur==0 ){
    rc = SQLITE_NOMEM;
    goto create_cursor_exception;
  }
  pCur->pgnoRoot = (Pgno)iTable;
  rc = sqlitepager_get(pBt->pPager, pCur->pgnoRoot, &pCur->pPage);
  if( rc!=SQLITE_OK ){
    goto create_cursor_exception;
  }
  rc = initPage(pCur->pPage, pCur->pgnoRoot, 0);
  if( rc!=SQLITE_OK ){
    goto create_cursor_exception;
  }







|







769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
  }
  pCur = sqliteMalloc( sizeof(*pCur) );
  if( pCur==0 ){
    rc = SQLITE_NOMEM;
    goto create_cursor_exception;
  }
  pCur->pgnoRoot = (Pgno)iTable;
  rc = sqlitepager_get(pBt->pPager, pCur->pgnoRoot, (void**)&pCur->pPage);
  if( rc!=SQLITE_OK ){
    goto create_cursor_exception;
  }
  rc = initPage(pCur->pPage, pCur->pgnoRoot, 0);
  if( rc!=SQLITE_OK ){
    goto create_cursor_exception;
  }
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783

784
785
786
787
788
789
790

create_cursor_exception:
  *ppCur = 0;
  if( pCur ){
    if( pCur->pPage ) sqlitepager_unref(pCur->pPage);
    sqliteFree(pCur);
  }
  unlinkBtree(pBt);
  return rc;
}

/*
** Close a cursor.  The lock on the database file is released
** when the last cursor is closed.
*/
int sqliteBtreeCloseCursor(BtCursor *pCur){
  Btree *pBt = pCur->pBt;
  int i;
  if( pCur->pPrev ){
    pCur->pPrev->pNext = pCur->pNext;
  }else{
    pBt->pCursor = pCur->pNext;
  }
  if( pCur->pNext ){
    pCur->pNext->pPrev = pCur->pPrev;
  }
  sqlitepager_unref(pCur->pPage);
  unlockBtree(pBt);
  sqliteFree(pCur);

}

/*
** Make a temporary cursor by filling in the fields of pTempCur.
** The temporary cursor is not on the cursor list for the Btree.
*/
static void getTempCursor(BtCursor *pCur, BtCursor *pTempCur){







|









<











>







794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810

811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829

create_cursor_exception:
  *ppCur = 0;
  if( pCur ){
    if( pCur->pPage ) sqlitepager_unref(pCur->pPage);
    sqliteFree(pCur);
  }
  unlockBtree(pBt);
  return rc;
}

/*
** Close a cursor.  The lock on the database file is released
** when the last cursor is closed.
*/
int sqliteBtreeCloseCursor(BtCursor *pCur){
  Btree *pBt = pCur->pBt;

  if( pCur->pPrev ){
    pCur->pPrev->pNext = pCur->pNext;
  }else{
    pBt->pCursor = pCur->pNext;
  }
  if( pCur->pNext ){
    pCur->pNext->pPrev = pCur->pPrev;
  }
  sqlitepager_unref(pCur->pPage);
  unlockBtree(pBt);
  sqliteFree(pCur);
  return SQLITE_OK;
}

/*
** Make a temporary cursor by filling in the fields of pTempCur.
** The temporary cursor is not on the cursor list for the Btree.
*/
static void getTempCursor(BtCursor *pCur, BtCursor *pTempCur){
815
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819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837

838
839
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844
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849
850
851
852
853
854
855
856
857
858
859
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861
862
863
864
865
866

  pPage = pCur->pPage;
  assert( pPage!=0 );
  if( pCur->idx >= pPage->nCell ){
    *pSize = 0;
  }else{
    pCell = pPage->apCell[pCur->idx];
    *psize = pCell->h.nKey;
  }
  return SQLITE_OK;
}

/*
** Read payload information from the entry that the pCur cursor is
** pointing to.  Begin reading the payload at "offset" and read
** a total of "amt" bytes.  Put the result in zBuf.
**
** This routine does not make a distinction between key and data.
** It just reads bytes from the payload area.
*/
static int getPayload(BtCursor *pCur, int offset, int amt, char *zBuf){
  char *aPayload;
  Pgno nextPage;

  assert( pCur!=0 && pCur->pPage!=0 );
  assert( pCur->idx>=0 && pCur->idx<pCur->nCell );
  aPayload = pCur->pPage->apCell[pCur->idx].aPayload;
  if( offset<MX_LOCAL_PAYLOAD ){
    int a = amt;
    if( a+offset>MX_LOCAL_PAYLOAD ){
      a = MX_LOCAL_PAYLOAD - offset;
    }
    memcpy(zBuf, &aPayload[offset], a);
    if( a==amt ){
      return SQLITE_OK;
    }
    offset += a;
    zBuf += a;
    amt -= a;
  }
  if( amt>0 ){
    nextPage = pCur->pPage->apCell[pCur->idx].ovfl;
  }
  while( amt>0 && nextPage ){
    OverflowPage *pOvfl;
    rc = sqlitepager_get(pCur->pBt->pPager, nextPage, &pOvfl);
    if( rc!=0 ){
      return rc;
    }
    nextPage = pOvfl->iNext;
    if( offset<OVERFLOW_SIZE ){
      int a = amt;
      if( a + offset > OVERFLOW_SIZE ){







|















>

|
|














|



|







854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
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878
879
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883
884
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886
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888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906

  pPage = pCur->pPage;
  assert( pPage!=0 );
  if( pCur->idx >= pPage->nCell ){
    *pSize = 0;
  }else{
    pCell = pPage->apCell[pCur->idx];
    *pSize = pCell->h.nKey;
  }
  return SQLITE_OK;
}

/*
** Read payload information from the entry that the pCur cursor is
** pointing to.  Begin reading the payload at "offset" and read
** a total of "amt" bytes.  Put the result in zBuf.
**
** This routine does not make a distinction between key and data.
** It just reads bytes from the payload area.
*/
static int getPayload(BtCursor *pCur, int offset, int amt, char *zBuf){
  char *aPayload;
  Pgno nextPage;
  int rc;
  assert( pCur!=0 && pCur->pPage!=0 );
  assert( pCur->idx>=0 && pCur->idx<pCur->pPage->nCell );
  aPayload = pCur->pPage->apCell[pCur->idx]->aPayload;
  if( offset<MX_LOCAL_PAYLOAD ){
    int a = amt;
    if( a+offset>MX_LOCAL_PAYLOAD ){
      a = MX_LOCAL_PAYLOAD - offset;
    }
    memcpy(zBuf, &aPayload[offset], a);
    if( a==amt ){
      return SQLITE_OK;
    }
    offset += a;
    zBuf += a;
    amt -= a;
  }
  if( amt>0 ){
    nextPage = pCur->pPage->apCell[pCur->idx]->ovfl;
  }
  while( amt>0 && nextPage ){
    OverflowPage *pOvfl;
    rc = sqlitepager_get(pCur->pBt->pPager, nextPage, (void**)&pOvfl);
    if( rc!=0 ){
      return rc;
    }
    nextPage = pOvfl->iNext;
    if( offset<OVERFLOW_SIZE ){
      int a = amt;
      if( a + offset > OVERFLOW_SIZE ){
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
** is on overflow pages and we are unable to access those overflow
** pages, then some other value might be returned to indicate the
** reason for the error.
*/
static int compareKey(BtCursor *pCur, char *pKey, int nKeyOrig, int *pResult){
  Pgno nextPage;
  int nKey = nKeyOrig;
  int n;
  Cell *pCell;

  assert( pCur->pPage );
  assert( pCur->idx>=0 && pCur->idx<pCur->pPage->nCell );
  pCell = pCur->pPage->apCell[pCur->idx];
  if( nKey > pCell->h.nKey ){
    nKey = pCell->h.nKey;







|







1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
** is on overflow pages and we are unable to access those overflow
** pages, then some other value might be returned to indicate the
** reason for the error.
*/
static int compareKey(BtCursor *pCur, char *pKey, int nKeyOrig, int *pResult){
  Pgno nextPage;
  int nKey = nKeyOrig;
  int n, c, rc;
  Cell *pCell;

  assert( pCur->pPage );
  assert( pCur->idx>=0 && pCur->idx<pCur->pPage->nCell );
  pCell = pCur->pPage->apCell[pCur->idx];
  if( nKey > pCell->h.nKey ){
    nKey = pCell->h.nKey;
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
  nKey -= n;
  nextPage = pCell->ovfl;
  while( nKey>0 ){
    OverflowPage *pOvfl;
    if( nextPage==0 ){
      return SQLITE_CORRUPT;
    }
    rc = sqlitepager_get(pCur->pBt->pPager, nextPage, &pOvfl);
    if( rc ){
      return rc;
    }
    nextPage = pOvfl->iNext;
    n = nKey;
    if( n>OVERFLOW_SIZE ){
      n = OVERFLOW_SIZE;







|







1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
  nKey -= n;
  nextPage = pCell->ovfl;
  while( nKey>0 ){
    OverflowPage *pOvfl;
    if( nextPage==0 ){
      return SQLITE_CORRUPT;
    }
    rc = sqlitepager_get(pCur->pBt->pPager, nextPage, (void**)&pOvfl);
    if( rc ){
      return rc;
    }
    nextPage = pOvfl->iNext;
    n = nKey;
    if( n>OVERFLOW_SIZE ){
      n = OVERFLOW_SIZE;
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
/*
** Move the cursor down to a new child page.
*/
static int moveToChild(BtCursor *pCur, int newPgno){
  int rc;
  MemPage *pNewPage;

  rc = sqlitepager_get(pCur->pBt->pPager, newPgno, &pNewPage);
  if( rc ){
    return rc;
  }
  initPage(pNewPage, newPgno, pCur->pPage);
  sqlitepager_unref(pCur->pPage);
  pCur->pPage = pNewPage;
  pCur->idx = 0;







|







1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
/*
** Move the cursor down to a new child page.
*/
static int moveToChild(BtCursor *pCur, int newPgno){
  int rc;
  MemPage *pNewPage;

  rc = sqlitepager_get(pCur->pBt->pPager, newPgno, (void**)&pNewPage);
  if( rc ){
    return rc;
  }
  initPage(pNewPage, newPgno, pCur->pPage);
  sqlitepager_unref(pCur->pPage);
  pCur->pPage = pNewPage;
  pCur->idx = 0;
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
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1074
1075
1076
** to the page we are coming from.  If we are coming from the
** right-most child page then pCur->idx is set to one more than
** the largest cell index.
*/
static int moveToParent(BtCursor *pCur){
  Pgno oldPgno;
  MemPage *pParent;

  pParent = pCur->pPage->pParent;
  if( pParent==0 ) return SQLITE_INTERNAL;
  oldPgno = sqlitepager_pagenumber(pCur->pPage);
  sqlitepager_ref(pParent);
  sqlitepager_unref(pCur->pPage);
  pCur->pPage = pParent;
  pCur->idx = pPage->nCell;
  for(i=0; i<pPage->nCell; i++){
    if( pPage->apCell[i].h.leftChild==oldPgno ){
      pCur->idx = i;
      break;
    }
  }
  return SQLITE_OK;
}

/*
** Move the cursor to the root page
*/
static int moveToRoot(BtCursor *pCur){
  MemPage *pNew;
  int rc;

  rc = sqlitepager_get(pCur->pBt->pPager, pCur->pgnoRoot, &pNew);
  if( rc ) return rc;
  sqlitepager_unref(pCur->pPage);
  pCur->pPage = pNew;
  pCur->idx = 0;
  return SQLITE_OK;
}








|






|
|
|














|







1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
** to the page we are coming from.  If we are coming from the
** right-most child page then pCur->idx is set to one more than
** the largest cell index.
*/
static int moveToParent(BtCursor *pCur){
  Pgno oldPgno;
  MemPage *pParent;
  int i;
  pParent = pCur->pPage->pParent;
  if( pParent==0 ) return SQLITE_INTERNAL;
  oldPgno = sqlitepager_pagenumber(pCur->pPage);
  sqlitepager_ref(pParent);
  sqlitepager_unref(pCur->pPage);
  pCur->pPage = pParent;
  pCur->idx = pParent->nCell;
  for(i=0; i<pParent->nCell; i++){
    if( pParent->apCell[i]->h.leftChild==oldPgno ){
      pCur->idx = i;
      break;
    }
  }
  return SQLITE_OK;
}

/*
** Move the cursor to the root page
*/
static int moveToRoot(BtCursor *pCur){
  MemPage *pNew;
  int rc;

  rc = sqlitepager_get(pCur->pBt->pPager, pCur->pgnoRoot, (void**)&pNew);
  if( rc ) return rc;
  sqlitepager_unref(pCur->pPage);
  pCur->pPage = pNew;
  pCur->idx = 0;
  return SQLITE_OK;
}

1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
  if( pCur->bSkipNext ){
    pCur->bSkipNext = 0;
    if( pRes ) *pRes = 0;
    return SQLITE_OK;
  }
  pCur->idx++;
  if( pCur->idx>=pCur->pPage->nCell ){
    if( pPage->u.hdr.rightChild ){
      rc = moveToChild(pCur, pPage->u.hdr.rightChild);
      if( rc ) return rc;
      rc = moveToLeftmost(pCur);
      if( rc ) return rc;
      if( pRes ) *pRes = 0;
      return SQLITE_OK;
    }
    do{
      if( pCur->pParent==0 ){
        if( pRes ) *pRes = 1;
        return SQLITE_OK;
      }
      rc = moveToParent(pCur);
      if( rc ) return rc;
    }while( pCur->idx>=pCur->pPage->nCell );
    if( pRes ) *pRes = 0;







|
|







|







1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
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1221
1222
1223
1224
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1226
1227
1228
1229
  if( pCur->bSkipNext ){
    pCur->bSkipNext = 0;
    if( pRes ) *pRes = 0;
    return SQLITE_OK;
  }
  pCur->idx++;
  if( pCur->idx>=pCur->pPage->nCell ){
    if( pCur->pPage->u.hdr.rightChild ){
      rc = moveToChild(pCur, pCur->pPage->u.hdr.rightChild);
      if( rc ) return rc;
      rc = moveToLeftmost(pCur);
      if( rc ) return rc;
      if( pRes ) *pRes = 0;
      return SQLITE_OK;
    }
    do{
      if( pCur->pPage->pParent==0 ){
        if( pRes ) *pRes = 1;
        return SQLITE_OK;
      }
      rc = moveToParent(pCur);
      if( rc ) return rc;
    }while( pCur->idx>=pCur->pPage->nCell );
    if( pRes ) *pRes = 0;
1205
1206
1207
1208
1209
1210
1211

1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
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1229
1230
1231
1232
1233
1234
1235
**
** SQLITE_OK is returned on success.  Any other return value indicates
** an error.  *ppPage and *pPgno are undefined in the event of an error.
** Do not invoke sqlitepager_unref() on *ppPage if an error is returned.
*/
static int allocatePage(Btree *pBt, MemPage **ppPage, Pgno *pPgno){
  PageOne *pPage1 = pBt->page1;

  if( pPage1->freeList ){
    OverflowPage *pOvfl;
    rc = sqlitepager_write(pPage1);
    if( rc ) return rc;
    *pPgno = pPage1->freeList;
    rc = sqlitepager_get(pBt->pPager, pPage1->freeList, &pOvfl);
    if( rc ) return rc;
    rc = sqlitepager_write(pOvfl);
    if( rc ){
      sqlitepager_unref(pOvfl);
      return rc;
    }
    pPage1->freeList = pOvfl->iNext;
    *ppPage = (MemPage*)pOvfl;
  }else{
    *pPgno = sqlitepager_pagecount(pBt->pPager);
    rc = sqlitepager_get(pBt->pPager, *pPgno, ppPage);
    if( rc ) return rc;
    rc = sqlitepager_write(*ppPage);
  }
  return rc;
}

/*







>





|










|







1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
**
** SQLITE_OK is returned on success.  Any other return value indicates
** an error.  *ppPage and *pPgno are undefined in the event of an error.
** Do not invoke sqlitepager_unref() on *ppPage if an error is returned.
*/
static int allocatePage(Btree *pBt, MemPage **ppPage, Pgno *pPgno){
  PageOne *pPage1 = pBt->page1;
  int rc;
  if( pPage1->freeList ){
    OverflowPage *pOvfl;
    rc = sqlitepager_write(pPage1);
    if( rc ) return rc;
    *pPgno = pPage1->freeList;
    rc = sqlitepager_get(pBt->pPager, pPage1->freeList, (void**)&pOvfl);
    if( rc ) return rc;
    rc = sqlitepager_write(pOvfl);
    if( rc ){
      sqlitepager_unref(pOvfl);
      return rc;
    }
    pPage1->freeList = pOvfl->iNext;
    *ppPage = (MemPage*)pOvfl;
  }else{
    *pPgno = sqlitepager_pagecount(pBt->pPager);
    rc = sqlitepager_get(pBt->pPager, *pPgno, (void**)ppPage);
    if( rc ) return rc;
    rc = sqlitepager_write(*ppPage);
  }
  return rc;
}

/*
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
  }
  rc = sqlitepager_write(pPage1);
  if( rc ){
    return rc;
  }
  if( pOvfl==0 ){
    assert( pgno>0 );
    rc = sqlitepager_get(pBt->pPager, pgno, &pOvfl);
    if( rc ) return rc;
    needOvflUnref = 1;
  }
  rc = sqlitepager_write(pOvfl);
  if( rc ){
    if( needOvflUnref ) sqlitepager_unref(pOvfl);
    return rc;
  }
  pOvfl->iNext = pPage1->freeList;
  pPage1->freeList = pgno;
  memset(pOvfl->aPayload, 0, OVERFLOW_SIZE);
  pPage->isInit = 0;
  assert( pPage->pParent==0 );
  rc = sqlitepager_unref(pOvfl);
  return rc;
}

/*
** Erase all the data out of a cell.  This involves returning overflow
** pages back the freelist.
*/
static int clearCell(Btree *pBt, Cell *pCell){
  Pager *pPager = pBt->pPager;
  OverflowPage *pOvfl;
  Pgno ovfl, nextOvfl;
  int rc;

  if( pCell->h.nKey + pCell->h.nData <= MX_LOCAL_PAYLOAD ){
    return SQLITE_OK;
  }
  ovfl = pCell->ovfl;
  pCell->ovfl = 0;
  while( ovfl ){
    rc = sqlitepager_get(pPager, ovfl, &pOvfl);
    if( rc ) return rc;
    nextOvfl = pOvfl->iNext;
    rc = freePage(pBt, pOvfl, ovfl);
    if( rc ) return rc;
    ovfl = nextOvfl;
    sqlitepager_unref(pOvfl);
  }
  return SQLITE_OK;
}

/*
** Create a new cell from key and data.  Overflow pages are allocated as
** necessary and linked to this cell.  
*/
static int fillInCell(
  Btree *pBt,              /* The whole Btree.  Needed to allocate pages */
  Cell *pCell,             /* Populate this Cell structure */
  void *pKey, int nKey,    /* The key */
  void *pData,int nData    /* The data */
){
  int OverflowPage *pOvfl;
  Pgno *pNext;
  int spaceLeft;
  int n;
  int nPayload;
  char *pPayload;
  char *pSpace;

  pCell->h.leftChild = 0;
  pCell->h.nKey = nKey;
  pCell->h.nData = nData;
  pCell->h.iNext = 0;

  pNext = &pCell->ovfl;
  pSpace = pCell->aPayload;
  spaceLeft = MX_LOCAL_PAYLOAD;
  pPayload = pKey;
  pKey = 0;
  nPayload = nKey;
  while( nPayload>0 ){
    if( spaceLeft==0 ){
      rc = allocatePage(pBt, &pOvfl, pNext);
      if( rc ){
        *pNext = 0;
        clearCell(pBt, pCell);
        return rc;
      }
      spaceLeft = OVERFLOW_SIZE;
      pSpace = pOvfl->aPayload;
      pNextPg = &pOvfl->iNext;
    }
    n = nPayload;
    if( n>spaceLeft ) n = spaceLeft;
    memcpy(pSpace, pPayload, n);
    nPayload -= n;
    if( nPayload==0 && pData ){
      pPayload = pData;







|











|
|




















|




















|


|

















|







|







1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
  }
  rc = sqlitepager_write(pPage1);
  if( rc ){
    return rc;
  }
  if( pOvfl==0 ){
    assert( pgno>0 );
    rc = sqlitepager_get(pBt->pPager, pgno, (void**)&pOvfl);
    if( rc ) return rc;
    needOvflUnref = 1;
  }
  rc = sqlitepager_write(pOvfl);
  if( rc ){
    if( needOvflUnref ) sqlitepager_unref(pOvfl);
    return rc;
  }
  pOvfl->iNext = pPage1->freeList;
  pPage1->freeList = pgno;
  memset(pOvfl->aPayload, 0, OVERFLOW_SIZE);
  ((MemPage*)pPage)->isInit = 0;
  assert( ((MemPage*)pPage)->pParent==0 );
  rc = sqlitepager_unref(pOvfl);
  return rc;
}

/*
** Erase all the data out of a cell.  This involves returning overflow
** pages back the freelist.
*/
static int clearCell(Btree *pBt, Cell *pCell){
  Pager *pPager = pBt->pPager;
  OverflowPage *pOvfl;
  Pgno ovfl, nextOvfl;
  int rc;

  if( pCell->h.nKey + pCell->h.nData <= MX_LOCAL_PAYLOAD ){
    return SQLITE_OK;
  }
  ovfl = pCell->ovfl;
  pCell->ovfl = 0;
  while( ovfl ){
    rc = sqlitepager_get(pPager, ovfl, (void**)&pOvfl);
    if( rc ) return rc;
    nextOvfl = pOvfl->iNext;
    rc = freePage(pBt, pOvfl, ovfl);
    if( rc ) return rc;
    ovfl = nextOvfl;
    sqlitepager_unref(pOvfl);
  }
  return SQLITE_OK;
}

/*
** Create a new cell from key and data.  Overflow pages are allocated as
** necessary and linked to this cell.  
*/
static int fillInCell(
  Btree *pBt,              /* The whole Btree.  Needed to allocate pages */
  Cell *pCell,             /* Populate this Cell structure */
  void *pKey, int nKey,    /* The key */
  void *pData,int nData    /* The data */
){
  OverflowPage *pOvfl;
  Pgno *pNext;
  int spaceLeft;
  int n, rc;
  int nPayload;
  char *pPayload;
  char *pSpace;

  pCell->h.leftChild = 0;
  pCell->h.nKey = nKey;
  pCell->h.nData = nData;
  pCell->h.iNext = 0;

  pNext = &pCell->ovfl;
  pSpace = pCell->aPayload;
  spaceLeft = MX_LOCAL_PAYLOAD;
  pPayload = pKey;
  pKey = 0;
  nPayload = nKey;
  while( nPayload>0 ){
    if( spaceLeft==0 ){
      rc = allocatePage(pBt, (MemPage**)&pOvfl, pNext);
      if( rc ){
        *pNext = 0;
        clearCell(pBt, pCell);
        return rc;
      }
      spaceLeft = OVERFLOW_SIZE;
      pSpace = pOvfl->aPayload;
      pNext = &pOvfl->iNext;
    }
    n = nPayload;
    if( n>spaceLeft ) n = spaceLeft;
    memcpy(pSpace, pPayload, n);
    nPayload -= n;
    if( nPayload==0 && pData ){
      pPayload = pData;
1379
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** Reparent all children of the given page to be the given page.
** In other words, for every child of pPage, invoke reparentPage()
** to make sure that child knows that pPage is its parent.
**
** This routine gets called after you memcpy() one page into
** another.
*/
static void reparentChildPages(Pager *pPager, Page *pPage){
  int i;
  for(i=0; i<pPage->nCell; i++){
    reparentPage(pPager, pPage->apCell[i]->leftChild, pPage);
  }
  reparentPage(pPager, pPage->u.hdr.rightChild, pPage);
}

/*
** Remove the i-th cell from pPage.  This routine effects pPage only.
** The cell content is not freed or deallocated.  It is assumed that
** the cell content has been copied someplace else.  This routine just
** removes the reference to the cell from pPage.
**
** "sz" must be the number of bytes in the cell.
**
** Do not bother maintaining the integrity of the linked list of Cells.
** Only pPage->apCell[] is important.  The relinkCellList() routine
** will be called soon after this routine in order to rebuild the
** linked list.
*/
static void dropCell(MemPage *pPage, int i, int sz){
  int j;
  assert( i>=0 && i<pPage->nCell );
  assert( sz==cellSize(pPage->apCell[i]);
  freeSpace(pPage, idx, sz);
  for(j=i, j<pPage->nCell-2; j++){
    pPage->apCell[j] = pPage->apCell[j+1];
  }
  pPage->nCell--;
}

/*
** Insert a new cell on pPage at cell index "i".  pCell points to the
** content of the cell.
**
** If the cell content will fit on the page, then put it there.  If it
** will not fit, then just make pPage->apCell[i] point to the content
** and set pPage->isOverfull.  
**
** Do not bother maintaining the integrity of the linked list of Cells.
** Only pPage->apCell[] is important.  The relinkCellList() routine
** will be called soon after this routine in order to rebuild the
** linked list.
*/
static void insertCell(MemPage *pPage, int i, Cell *pCell, int sz){
  int idx, j;
  assert( i>=0 && i<=pPage->nCell );
  assert( sz==cellSize(pCell) );
  for(j=pPage->nCell; j>i; j--){
    pPage->apCell[j] = pPage->apCell[j-1];
  }
  pPage->nCell++;
  idx = allocateSpace(pPage, sz);
  if( idx<=0 ){
    pPage->isOverfull = 1;
    pPage->apCell[i] = pCell;
  }else{
    memcpy(&pPage->u.aDisk[idx], pCell, sz);
    pPage->apCell[i] = (Cell*)&pPage->u.aDisk[idx]);
  }
}

/*
** Rebuild the linked list of cells on a page so that the cells
** occur in the order specified by pPage->apCell[].  Invoke this
** routine once to repair damage after one or more invocations
** of either insertCell() or dropCell().
*/
static void relinkCellList(MemPage *pPage){
  int i;
  u16 *pIdx;
  pIdx = &pPage->u.hdr.firstCell;
  for(i=0; i<pPage->nCell; i++){
    int idx = ((uptr)pPage->apCell[i]) - (uptr)pPage;

    *pIdx = idx;
    pIdx = &pPage->apCell[i]->h.iNext;
  }
  *pIdx = 0;
}

/*







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** Reparent all children of the given page to be the given page.
** In other words, for every child of pPage, invoke reparentPage()
** to make sure that child knows that pPage is its parent.
**
** This routine gets called after you memcpy() one page into
** another.
*/
static void reparentChildPages(Pager *pPager, MemPage *pPage){
  int i;
  for(i=0; i<pPage->nCell; i++){
    reparentPage(pPager, pPage->apCell[i]->h.leftChild, pPage);
  }
  reparentPage(pPager, pPage->u.hdr.rightChild, pPage);
}

/*
** Remove the i-th cell from pPage.  This routine effects pPage only.
** The cell content is not freed or deallocated.  It is assumed that
** the cell content has been copied someplace else.  This routine just
** removes the reference to the cell from pPage.
**
** "sz" must be the number of bytes in the cell.
**
** Do not bother maintaining the integrity of the linked list of Cells.
** Only the pPage->apCell[] array is important.  The relinkCellList() 
** routine will be called soon after this routine in order to rebuild 
** the linked list.
*/
static void dropCell(MemPage *pPage, int idx, int sz){
  int j;
  assert( idx>=0 && idx<pPage->nCell );
  assert( sz==cellSize(pPage->apCell[idx]) );
  freeSpace(pPage, idx, sz);
  for(j=idx; j<pPage->nCell-2; j++){
    pPage->apCell[j] = pPage->apCell[j+1];
  }
  pPage->nCell--;
}

/*
** Insert a new cell on pPage at cell index "i".  pCell points to the
** content of the cell.
**
** If the cell content will fit on the page, then put it there.  If it
** will not fit, then just make pPage->apCell[i] point to the content
** and set pPage->isOverfull.  
**
** Do not bother maintaining the integrity of the linked list of Cells.
** Only the pPage->apCell[] array is important.  The relinkCellList() 
** routine will be called soon after this routine in order to rebuild 
** the linked list.
*/
static void insertCell(MemPage *pPage, int i, Cell *pCell, int sz){
  int idx, j;
  assert( i>=0 && i<=pPage->nCell );
  assert( sz==cellSize(pCell) );
  for(j=pPage->nCell; j>i; j--){
    pPage->apCell[j] = pPage->apCell[j-1];
  }
  pPage->nCell++;
  idx = allocateSpace(pPage, sz);
  if( idx<=0 ){
    pPage->isOverfull = 1;
    pPage->apCell[i] = pCell;
  }else{
    memcpy(&pPage->u.aDisk[idx], pCell, sz);
    pPage->apCell[i] = (Cell*)&pPage->u.aDisk[idx];
  }
}

/*
** Rebuild the linked list of cells on a page so that the cells
** occur in the order specified by the pPage->apCell[] array.  
** Invoke this routine once to repair damage after one or more
** invocations of either insertCell() or dropCell().
*/
static void relinkCellList(MemPage *pPage){
  int i;
  u16 *pIdx;
  pIdx = &pPage->u.hdr.firstCell;
  for(i=0; i<pPage->nCell; i++){
    int idx = addr(pPage->apCell[i]) - addr(pPage);
    assert( idx>0 && idx<SQLITE_PAGE_SIZE );
    *pIdx = idx;
    pIdx = &pPage->apCell[i]->h.iNext;
  }
  *pIdx = 0;
}

/*
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1503
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1515
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1519




1520
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1543


1544
1545
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1548
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1550
  int i;
  memcpy(pTo->u.aDisk, pFrom->u.aDisk, SQLITE_PAGE_SIZE);
  pTo->pParent = pFrom->pParent;
  pTo->isInit = 1;
  pTo->nCell = pFrom->nCell;
  pTo->nFree = pFrom->nFree;
  pTo->isOverfull = pFrom->isOverfull;
  to = (unsigned int)pTo;
  from = (unsigned int)pFrom;
  for(i=0; i<pTo->nCell; i++){
    uptr addr = (uptr)(pFrom->apCell[i]);
    if( addr>from && addr<from+SQLITE_PAGE_SIZE ){
      *((uptr*)&pTo->apCell[i]) = addr + to - from;
    }
  }
}

/*
** This routine redistributes Cells on pPage and up to two siblings
** of pPage so that all pages have about the same amount of free space.
** Usually one sibling on either side of pPage is used in the balancing,
** though both siblings might come from one side if pPage is the first
** or last child of its parent.  If pPage has fewer than two siblings
** (something which can only happen if pPage is the root page or a 
** child of root) then all available siblings participate in the balancing.
**
** The number of siblings of pPage might be increased or decreased by
** one in order to keep all pages between 2/3 and completely full.  If

** pPage is the root page, then the depth of the tree might be increased
** or decreased by one, as necessary, to keep the root page from being
** overfull or empty.
**
** This routine calls relinkCellList() on its input page regardless of
** whether or not it does any real balancing.  Client routines will typically
** invoke insertCell() or dropCell() before calling this routine, so we
** need to call relinkCellList() to clean up the mess that those other
** routines left behind.
**
** pCur is left pointing to the same cell as when this routine was called
** event if that cell gets moved to a different page.  pCur may be NULL.


**
** Note that when this routine is called, some of the Cells on pPage
** might not actually be stored in pPage->u.aDisk[].  This can happen
** if the page is overfull.  Part of the job of this routine is to
** make sure all Cells for pPage once again fit in pPage->u.aDisk[].




**
** If this routine fails for any reason, it means the database may have
** been left in a corrupted state and should be rolled back.
*/
static int balance(Btree *pBt, MemPage *pPage, BtCursor *pCur){
  MemPage *pParent;            /* The parent of pPage */
  MemPage *apOld[3];           /* pPage and up to two siblings */
  Pgno pgnoOld[3];             /* Page numbers for each page in apOld[] */
  MemPage *apNew[4];           /* pPage and up to 3 siblings after balancing */
  Pgno pgnoNew[4];             /* Page numbers for each page in apNew[] */
  int idxDiv[3];               /* Indices of divider cells in pParent */
  Cell *apDiv[3];              /* Divider cells in pParent */
  int nCell;                   /* Number of cells in apCell[] */
  int nOld;                    /* Number of pages in apOld[] */
  int nNew;                    /* Number of pages in apNew[] */
  int perPage;                 /* Approximate number of bytes per page */
  int nDiv;                    /* Number of cells in apDiv[] */
  int i, j, k;                 /* Loop counters */
  int idx;                     /* Index of pPage in pParent->apCell[] */
  int nxDiv;                   /* Next divider slot in pParent->apCell[] */
  int rc;                      /* The return code */
  int iCur;                    /* apCell[iCur] is the cell of the cursor */
  int usedPerPage;             /* Memory needed for each page */
  int freePerPage;             /* Average free space per page */


  Cell *apCell[MX_CELL*3+5];   /* All cells from pages being balanceed */
  int szCell[MX_CELL*3+5];     /* Local size of all cells */
  Cell aTemp[2];               /* Temporary holding area for apDiv[] */
  MemPage aOld[3];             /* Temporary copies of pPage and its siblings */

  /* 
  ** Return without doing any work if pPage is neither overfull nor







|
|

|
|
|














|
>
|










|
>
>





>
>
>
>















<








>
>







1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583

1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
  int i;
  memcpy(pTo->u.aDisk, pFrom->u.aDisk, SQLITE_PAGE_SIZE);
  pTo->pParent = pFrom->pParent;
  pTo->isInit = 1;
  pTo->nCell = pFrom->nCell;
  pTo->nFree = pFrom->nFree;
  pTo->isOverfull = pFrom->isOverfull;
  to = addr(pTo);
  from = addr(pFrom);
  for(i=0; i<pTo->nCell; i++){
    uptr x = addr(pFrom->apCell[i]);
    if( x>from && x<from+SQLITE_PAGE_SIZE ){
      *((uptr*)&pTo->apCell[i]) = x + to - from;
    }
  }
}

/*
** This routine redistributes Cells on pPage and up to two siblings
** of pPage so that all pages have about the same amount of free space.
** Usually one sibling on either side of pPage is used in the balancing,
** though both siblings might come from one side if pPage is the first
** or last child of its parent.  If pPage has fewer than two siblings
** (something which can only happen if pPage is the root page or a 
** child of root) then all available siblings participate in the balancing.
**
** The number of siblings of pPage might be increased or decreased by
** one in an effort to keep pages between 66% and 100% full. The root page
** is special and is allowed to be less than 66% full. If pPage is 
** the root page, then the depth of the tree might be increased
** or decreased by one, as necessary, to keep the root page from being
** overfull or empty.
**
** This routine calls relinkCellList() on its input page regardless of
** whether or not it does any real balancing.  Client routines will typically
** invoke insertCell() or dropCell() before calling this routine, so we
** need to call relinkCellList() to clean up the mess that those other
** routines left behind.
**
** pCur is left pointing to the same cell as when this routine was called
** even if that cell gets moved to a different page.  pCur may be NULL.
** Set the pCur parameter to NULL if you do not care about keeping track
** of a cell as that will save this routine the work of keeping track of it.
**
** Note that when this routine is called, some of the Cells on pPage
** might not actually be stored in pPage->u.aDisk[].  This can happen
** if the page is overfull.  Part of the job of this routine is to
** make sure all Cells for pPage once again fit in pPage->u.aDisk[].
**
** In the course of balancing the siblings of pPage, the parent of pPage
** might become overfull or underfull.  If that happens, then this routine
** is called recursively on the parent.
**
** If this routine fails for any reason, it means the database may have
** been left in a corrupted state and should be rolled back.
*/
static int balance(Btree *pBt, MemPage *pPage, BtCursor *pCur){
  MemPage *pParent;            /* The parent of pPage */
  MemPage *apOld[3];           /* pPage and up to two siblings */
  Pgno pgnoOld[3];             /* Page numbers for each page in apOld[] */
  MemPage *apNew[4];           /* pPage and up to 3 siblings after balancing */
  Pgno pgnoNew[4];             /* Page numbers for each page in apNew[] */
  int idxDiv[3];               /* Indices of divider cells in pParent */
  Cell *apDiv[3];              /* Divider cells in pParent */
  int nCell;                   /* Number of cells in apCell[] */
  int nOld;                    /* Number of pages in apOld[] */
  int nNew;                    /* Number of pages in apNew[] */

  int nDiv;                    /* Number of cells in apDiv[] */
  int i, j, k;                 /* Loop counters */
  int idx;                     /* Index of pPage in pParent->apCell[] */
  int nxDiv;                   /* Next divider slot in pParent->apCell[] */
  int rc;                      /* The return code */
  int iCur;                    /* apCell[iCur] is the cell of the cursor */
  int usedPerPage;             /* Memory needed for each page */
  int freePerPage;             /* Average free space per page */
  int totalSize;               /* Total bytes for all cells */
  Pgno pgno;                   /* Page number */
  Cell *apCell[MX_CELL*3+5];   /* All cells from pages being balanceed */
  int szCell[MX_CELL*3+5];     /* Local size of all cells */
  Cell aTemp[2];               /* Temporary holding area for apDiv[] */
  MemPage aOld[3];             /* Temporary copies of pPage and its siblings */

  /* 
  ** Return without doing any work if pPage is neither overfull nor
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
  ** Find the parent of the page to be balanceed.
  ** If there is no parent, it means this page is the root page and
  ** special rules apply.
  */
  pParent = pPage->pParent;
  if( pParent==0 ){
    Pgno pgnoChild;
    Page *pChild;
    if( pPage->nCell==0 ){
      if( pPage->u.hdr.rightChild ){
        /*
        ** The root page is empty.  Copy the one child page
        ** into the root page and return.  This reduces the depth
        ** of the BTree by one.
        */
        rc = sqlitepager_write(pPage);
        if( rc ) return rc;
        pgnoChild = pPage->u.hdr.rightChild;
        rc = sqlitepager_get(pBt, pgnoChild, &pChild);
        if( rc ) return rc;
        memcpy(pPage, pChild, SQLITE_PAGE_SIZE);
        pPage->isInit = 0;
        initPage(pPage, sqlitepager_pagenumber(pPage), 0);
        reparentChildPages(pBt->pPager, pPage);
        freePage(pBt, pChild, pgnoChild);
        sqlitepager_unref(pChild);







|










|







1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
  ** Find the parent of the page to be balanceed.
  ** If there is no parent, it means this page is the root page and
  ** special rules apply.
  */
  pParent = pPage->pParent;
  if( pParent==0 ){
    Pgno pgnoChild;
    MemPage *pChild;
    if( pPage->nCell==0 ){
      if( pPage->u.hdr.rightChild ){
        /*
        ** The root page is empty.  Copy the one child page
        ** into the root page and return.  This reduces the depth
        ** of the BTree by one.
        */
        rc = sqlitepager_write(pPage);
        if( rc ) return rc;
        pgnoChild = pPage->u.hdr.rightChild;
        rc = sqlitepager_get(pBt->pPager, pgnoChild, (void**)&pChild);
        if( rc ) return rc;
        memcpy(pPage, pChild, SQLITE_PAGE_SIZE);
        pPage->isInit = 0;
        initPage(pPage, sqlitepager_pagenumber(pPage), 0);
        reparentChildPages(pBt->pPager, pPage);
        freePage(pBt, pChild, pgnoChild);
        sqlitepager_unref(pChild);
1664
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1669
1670
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1672
1673
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1681
1682
  for(i=0, k=nxDiv; i<3; i++, k++){
    if( k<pParent->nCell ){
      idxDiv[i] = k;
      apDiv[i] = pParent->apCell[k];
      nDiv++;
      pgnoOld[i] = apDiv[i]->h.leftChild;
    }else if( k==pParent->nCell ){
      pgnoOld[i] = pParent->rightChild;
    }else{
      break;
    }
    rc = sqlitepager_get(pBt, pgnoOld[i], &apOld[i]);
    if( rc ) goto balance_cleanup;
    nOld++;
  }

  /*
  ** Set iCur to be the index in apCell[] of the cell that the cursor
  ** is pointing to.  We will need this later on in order to keep the







|



|







1714
1715
1716
1717
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1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
  for(i=0, k=nxDiv; i<3; i++, k++){
    if( k<pParent->nCell ){
      idxDiv[i] = k;
      apDiv[i] = pParent->apCell[k];
      nDiv++;
      pgnoOld[i] = apDiv[i]->h.leftChild;
    }else if( k==pParent->nCell ){
      pgnoOld[i] = pParent->u.hdr.rightChild;
    }else{
      break;
    }
    rc = sqlitepager_get(pBt->pPager, pgnoOld[i], (void**)&apOld[i]);
    if( rc ) goto balance_cleanup;
    nOld++;
  }

  /*
  ** Set iCur to be the index in apCell[] of the cell that the cursor
  ** is pointing to.  We will need this later on in order to keep the
1715
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1717
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1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
    for(j=0; j<pOld->nCell; j++){
      apCell[nCell] = pOld->apCell[j];
      szCell[nCell] = cellSize(apCell[nCell]);
      nCell++;
    }
    if( i<nOld-1 ){
      szCell[nCell] = cellSize(apDiv[i]);
      memcpy(aTemp[i], apDiv[i], szCell[nCell]);
      apCell[nCell] = &aTemp[i];
      dropCell(pParent, nxDiv, szCell[nCell]);
      assert( apCell[nCell]->h.leftChild==pgnoOld[i] );
      apCell[nCell]->h.leftChild = pOld->u.hdr.rightChild;
      nCell++;
    }
  }







|







1765
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1767
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1770
1771
1772
1773
1774
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1776
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1778
1779
    for(j=0; j<pOld->nCell; j++){
      apCell[nCell] = pOld->apCell[j];
      szCell[nCell] = cellSize(apCell[nCell]);
      nCell++;
    }
    if( i<nOld-1 ){
      szCell[nCell] = cellSize(apDiv[i]);
      memcpy(&aTemp[i], apDiv[i], szCell[nCell]);
      apCell[nCell] = &aTemp[i];
      dropCell(pParent, nxDiv, szCell[nCell]);
      assert( apCell[nCell]->h.leftChild==pgnoOld[i] );
      apCell[nCell]->h.leftChild = pOld->u.hdr.rightChild;
      nCell++;
    }
  }
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** sqliteBtreeNext() after a delete and the cursor will be left
** pointing to the first entry after the deleted entry.
*/
int sqliteBtreeDelete(BtCursor *pCur){
  MemPage *pPage = pCur->pPage;
  Cell *pCell;
  int rc;


  if( !pCur->pBt->inTrans ){
    return SQLITE_ERROR;  /* Must start a transaction first */
  }
  if( pCur->idx >= pPage->nCell ){
    return SQLITE_ERROR;  /* The cursor is not pointing to anything */
  }
  rc = sqlitepager_write(pPage);
  if( rc ) return rc;
  pCell = pPage->apCell[pCur->idx];
  pgnoChild = pCell->h.leftChild;
  clearCell(pCell);
  dropCell(pPage, pCur->idx, cellSize(pCell));
  if( pgnoChild ){
    /*
    ** If the entry we just deleted is not a leaf, then we've left a
    ** whole in an internal page.  We have to fill the whole by moving
    ** in a page from a leaf.  The next Cell after the one just deleted
    ** is guaranteed to exist and to be a leaf so we can use it.
    */
    BtCursor leafCur;
    Cell *pNext;
    int szNext;
    getTempCursor(pCur, &leafCur);
    rc = sqliteBtreeNext(&leafCur, 0);
    if( rc!=SQLITE_OK ){
      return SQLITE_CORRUPT;
    }
    pNext = leafCur.pPage->apCell[leafCur.idx]
    szNext = cellSize(pNext);

    insertCell(pPage, pCur->idx, pNext, szNext);
    rc = balance(pCur->pBt, pPage, pCur);
    if( rc ) return rc;
    pCur->bSkipNext = 1;
    dropCell(leafCur.pPage, leafCur.idx, szNext);
    rc = balance(pCur->pBt, leafCur.pPage, 0);
    releaseTempCur(&leafCur);
  }else{
    rc = balance(pCur->pBt, pPage, pCur);
    pCur->bSkipNext = 1;
  }
  return rc;
}








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** sqliteBtreeNext() after a delete and the cursor will be left
** pointing to the first entry after the deleted entry.
*/
int sqliteBtreeDelete(BtCursor *pCur){
  MemPage *pPage = pCur->pPage;
  Cell *pCell;
  int rc;
  Pgno pgnoChild;

  if( !pCur->pBt->inTrans ){
    return SQLITE_ERROR;  /* Must start a transaction first */
  }
  if( pCur->idx >= pPage->nCell ){
    return SQLITE_ERROR;  /* The cursor is not pointing to anything */
  }
  rc = sqlitepager_write(pPage);
  if( rc ) return rc;
  pCell = pPage->apCell[pCur->idx];
  pgnoChild = pCell->h.leftChild;
  clearCell(pCur->pBt, pCell);
  dropCell(pPage, pCur->idx, cellSize(pCell));
  if( pgnoChild ){
    /*
    ** If the entry we just deleted is not a leaf, then we've left a
    ** hole in an internal page.  We have to fill the hole by moving
    ** in a cell from a leaf.  The next Cell after the one just deleted
    ** is guaranteed to exist and to be a leaf so we can use it.
    */
    BtCursor leafCur;
    Cell *pNext;
    int szNext;
    getTempCursor(pCur, &leafCur);
    rc = sqliteBtreeNext(&leafCur, 0);
    if( rc!=SQLITE_OK ){
      return SQLITE_CORRUPT;
    }
    pNext = leafCur.pPage->apCell[leafCur.idx];
    szNext = cellSize(pNext);
    pNext->h.leftChild = pgnoChild;
    insertCell(pPage, pCur->idx, pNext, szNext);
    rc = balance(pCur->pBt, pPage, pCur);
    if( rc ) return rc;
    pCur->bSkipNext = 1;
    dropCell(leafCur.pPage, leafCur.idx, szNext);
    rc = balance(pCur->pBt, leafCur.pPage, 0);
    releaseTempCursor(&leafCur);
  }else{
    rc = balance(pCur->pBt, pPage, pCur);
    pCur->bSkipNext = 1;
  }
  return rc;
}

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/*
** Erase the given database page and all its children.  Return
** the page to the freelist.
*/
static int clearDatabasePage(Btree *pBt, Pgno pgno){
  MemPage *pPage;
  int rc;
  int i;
  Cell *pCell;
  int idx;

  rc = sqlitepager_get(pBt->pPager, pgno, &pPage);
  if( rc ) return rc;
  idx = pPage->u.hdr.firstCell;
  while( idx>0 ){
    pCell = (Cell*)&pPage->u.aDisk[idx];
    idx = pCell->h.iNext;
    if( pCell->h.leftChild ){
      rc = clearDatabasePage(pBt, pCell->h.leftChild);
      if( rc ) return rc;
    }
    rc = clearCell(pCell);
    if( rc ) return rc;
  }


  return freePage(pBt, pPage, pgno);
}

/*
** Delete all information from a single table in the database.
*/
int sqliteBtreeClearTable(Btree *pBt, int iTable){
  int rc;
  if( !pBt->inTrans ){
    return SQLITE_ERROR;  /* Must start a transaction first */
  }
  rc = clearDatabasePage(pBt, (Pgno)iTable);
  if( rc ){
    sqliteBtreeRollback(pBt);
    return rc;
  }

}

/*
** Erase all information in a table and add the root of the table to
** the freelist.  Except, the root of the principle table (the one on
** page 2) is never added to the freelist.
*/
int sqliteBtreeDropTable(Btree *pBt, int iTable){
  int rc;
  MemPage *pPage;
  if( !pBt->inTrans ){
    return SQLITE_ERROR;  /* Must start a transaction first */
  }
  rc = sqlitepager_get(pBt->pPager, (Pgno)iTable, &pPage);
  if( rc==SQLITE_OK ){
    rc = sqliteBtreeClearTable(pBt, iTable);
  }
  if( rc==SQLITE_OK && iTable!=2 ){
    rc = freePage(pBt, pPage, (Pgno)iTable);
  }
  sqlitepager_unref(pPage);
  return rc;  
}

/*
** Read the meta-information out of a database file.
*/
int sqliteBtreeGetMeta(Btree *pBt, int *aMeta){
  PageOne *pP1;
  int rc;

  rc = sqlitepager_get(pBt->pPager, 1, &pP1);
  if( rc ) return rc;
  memcpy(aMeta, pP1->aMeta, sizeof(pP1->aMeta));
  sqlitepager_unref(pP1);
  return SQLITE_OK;
}

/*







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/*
** Erase the given database page and all its children.  Return
** the page to the freelist.
*/
static int clearDatabasePage(Btree *pBt, Pgno pgno){
  MemPage *pPage;
  int rc;

  Cell *pCell;
  int idx;

  rc = sqlitepager_get(pBt->pPager, pgno, (void**)&pPage);
  if( rc ) return rc;
  idx = pPage->u.hdr.firstCell;
  while( idx>0 ){
    pCell = (Cell*)&pPage->u.aDisk[idx];
    idx = pCell->h.iNext;
    if( pCell->h.leftChild ){
      rc = clearDatabasePage(pBt, pCell->h.leftChild);
      if( rc ) return rc;
    }
    rc = clearCell(pBt, pCell);
    if( rc ) return rc;
  }
  rc = clearDatabasePage(pBt, pPage->u.hdr.rightChild);
  if( rc ) return rc;
  return freePage(pBt, pPage, pgno);
}

/*
** Delete all information from a single table in the database.
*/
int sqliteBtreeClearTable(Btree *pBt, int iTable){
  int rc;
  if( !pBt->inTrans ){
    return SQLITE_ERROR;  /* Must start a transaction first */
  }
  rc = clearDatabasePage(pBt, (Pgno)iTable);
  if( rc ){
    sqliteBtreeRollback(pBt);

  }
  return rc;
}

/*
** Erase all information in a table and add the root of the table to
** the freelist.  Except, the root of the principle table (the one on
** page 2) is never added to the freelist.
*/
int sqliteBtreeDropTable(Btree *pBt, int iTable){
  int rc;
  MemPage *pPage;
  if( !pBt->inTrans ){
    return SQLITE_ERROR;  /* Must start a transaction first */
  }
  rc = sqlitepager_get(pBt->pPager, (Pgno)iTable, (void**)&pPage);
  if( rc==SQLITE_OK ){
    rc = sqliteBtreeClearTable(pBt, iTable);
  }
  if( rc==SQLITE_OK && iTable!=2 ){
    rc = freePage(pBt, pPage, (Pgno)iTable);
  }
  sqlitepager_unref(pPage);
  return rc;  
}

/*
** Read the meta-information out of a database file.
*/
int sqliteBtreeGetMeta(Btree *pBt, int *aMeta){
  PageOne *pP1;
  int rc;

  rc = sqlitepager_get(pBt->pPager, 1, (void**)&pP1);
  if( rc ) return rc;
  memcpy(aMeta, pP1->aMeta, sizeof(pP1->aMeta));
  sqlitepager_unref(pP1);
  return SQLITE_OK;
}

/*
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  }
  pP1 = pBt->page1;
  rc = sqlitepager_write(pP1);
  if( rc ) return rc;
  memcpy(pP1->aMeta, aMeta, sizeof(pP1->aMeta));
  return SQLITE_OK;
}














































































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  }
  pP1 = pBt->page1;
  rc = sqlitepager_write(pP1);
  if( rc ) return rc;
  memcpy(pP1->aMeta, aMeta, sizeof(pP1->aMeta));
  return SQLITE_OK;
}

#ifdef SQLITE_TEST
/*
** Print a disassembly of the given page on standard output.  This routine
** is used for debugging and testing only.
*/
int sqliteBtreePageDump(Btree *pBt, int pgno){
  int rc;
  MemPage *pPage;
  int i, j;
  int nFree;
  u16 idx;
  char range[20];
  unsigned char payload[20];
  rc = sqlitepager_get(pBt->pPager, (Pgno)pgno, (void**)&pPage);
  if( rc ){
    return rc;
  }
  i = 0;
  idx = pPage->u.hdr.firstCell;
  while( idx>0 && idx<=SQLITE_PAGE_SIZE-MIN_CELL_SIZE ){
    Cell *pCell = (Cell*)&pPage->u.aDisk[idx];
    int sz = cellSize(pCell);
    sprintf(range,"%d..%d", idx, idx+sz-1);
    if( sz>sizeof(payload)-1 ) sz = sizeof(payload)-1;
    memcpy(payload, pCell->aPayload, sz);
    for(j=0; j<sz; j++){
      if( payload[j]<0x20 || payload[j]>0x7f ) payload[j] = '.';
    }
    payload[sz] = 0;
    printf(
      "cell %2d: i=%-10s chld=%-4d nk=%-3d nd=%-3d payload=%s\n",
      i, range, (int)pCell->h.leftChild, pCell->h.nKey, pCell->h.nData,
      pCell->aPayload
    );
    idx = pCell->h.iNext;
  }
  if( idx!=0 ){
    printf("ERROR: next cell index out of range: %d\n", idx);
  }
  printf("right_child: %d\n", pPage->u.hdr.rightChild);
  nFree = 0;
  i = 0;
  idx = pPage->u.hdr.firstFree;
  while( idx>0 && idx<SQLITE_PAGE_SIZE ){
    FreeBlk *p = (FreeBlk*)&pPage->u.aDisk[idx];
    sprintf(range,"%d..%d", idx, idx+p->iSize-1);
    nFree += p->iSize;
    printf("freeblock %2d: i=%-10s size=%-4d total=%d\n",
       i, range, p->iSize, nFree);
    idx = p->iNext;
  }
  if( idx!=0 ){
    printf("ERROR: next freeblock index out of range: %d\n", idx);
  }
  sqlitepager_unref(pPage);
  return SQLITE_OK;
}
#endif

#ifdef SQLITE_TEST
/*
** Put the page number and index of a cursor into aResult[0] and aResult[1]
** This routine is used for debugging and testing only.
*/
int sqliteBtreeCursorDump(BtCursor *pCur, int *aResult){
  aResult[0] = sqlitepager_pagenumber(pCur->pPage);
  aResult[1] = pCur->idx;
  return SQLITE_OK;
}
#endif
Changes to src/btree.h.
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**   drh@hwaci.com
**   http://www.hwaci.com/drh/
**
*************************************************************************
** This header file defines the interface that the sqlite B-Tree file
** subsystem.
**
** @(#) $Id: btree.h,v 1.4 2001/06/08 00:21:53 drh Exp $
*/

typedef struct Btree Btree;
typedef struct BtCursor BtCursor;

int sqliteBtreeOpen(const char *zFilename, int mode, Btree **ppBtree);
int sqliteBtreeClose(Btree*);

int sqliteBtreeBeginTrans(Btree*);
int sqliteBtreeCommit(Btree*);
int sqliteBtreeRollback(Btree*);

int sqliteBtreeCreateTable(Btree*, int*);
int sqliteBtreeDropTable(Btree*, int);
int sqliteBtreeClearTable(Btree*, int);

int sqliteBtreeCursor(Btree*, int iTable, BtCursor **ppCur);
int sqliteBtreeMoveto(BtCursor*, void *pKey, int nKey, *pRes);
int sqliteBtreeDelete(BtCursor*);
int sqliteBtreeInsert(BtCursor*, void *pKey, int nKey, void *pData, int nData);
int sqliteBtreeNext(BtCursor*, int *pRes);
int sqliteBtreeKeySize(BtCursor*, int *pSize);
int sqliteBtreeKey(BtCursor*, int offset, int amt, char *zBuf);
int sqliteBtreeDataSize(BtCursor*, int *pSize);
int sqliteBtreeData(BtCursor*, int offset, int amt, char *zBuf);
int sqliteBtreeCloseCursor(BtCursor*);

#define SQLITE_N_BTREE_META 3
int sqliteBtreeGetMeta(Btree*, int*);
int sqliteBtreeUpdateMeta(Btree*, int*);













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>
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**   drh@hwaci.com
**   http://www.hwaci.com/drh/
**
*************************************************************************
** This header file defines the interface that the sqlite B-Tree file
** subsystem.
**
** @(#) $Id: btree.h,v 1.5 2001/06/22 19:15:00 drh Exp $
*/

typedef struct Btree Btree;
typedef struct BtCursor BtCursor;

int sqliteBtreeOpen(const char *zFilename, int mode, Btree **ppBtree);
int sqliteBtreeClose(Btree*);

int sqliteBtreeBeginTrans(Btree*);
int sqliteBtreeCommit(Btree*);
int sqliteBtreeRollback(Btree*);

int sqliteBtreeCreateTable(Btree*, int*);
int sqliteBtreeDropTable(Btree*, int);
int sqliteBtreeClearTable(Btree*, int);

int sqliteBtreeCursor(Btree*, int iTable, BtCursor **ppCur);
int sqliteBtreeMoveto(BtCursor*, void *pKey, int nKey, int *pRes);
int sqliteBtreeDelete(BtCursor*);
int sqliteBtreeInsert(BtCursor*, void *pKey, int nKey, void *pData, int nData);
int sqliteBtreeNext(BtCursor*, int *pRes);
int sqliteBtreeKeySize(BtCursor*, int *pSize);
int sqliteBtreeKey(BtCursor*, int offset, int amt, char *zBuf);
int sqliteBtreeDataSize(BtCursor*, int *pSize);
int sqliteBtreeData(BtCursor*, int offset, int amt, char *zBuf);
int sqliteBtreeCloseCursor(BtCursor*);

#define SQLITE_N_BTREE_META 3
int sqliteBtreeGetMeta(Btree*, int*);
int sqliteBtreeUpdateMeta(Btree*, int*);


#ifdef SQLITE_TEST
int sqliteBtreePageDump(Btree*, int);
int sqliteBtreeCursorDump(BtCursor*, int*);
#endif
Changes to src/pager.c.
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*************************************************************************
** This is the implementation of the page cache subsystem.
** 
** The page cache is used to access a database file.  The pager journals
** all writes in order to support rollback.  Locking is used to limit
** access to one or more reader or one writer.
**
** @(#) $Id: pager.c,v 1.8 2001/06/02 02:40:57 drh Exp $
*/
#include "sqliteInt.h"
#include "pager.h"
#include <fcntl.h>
#include <sys/stat.h>
#include <unistd.h>
#include <assert.h>







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*************************************************************************
** This is the implementation of the page cache subsystem.
** 
** The page cache is used to access a database file.  The pager journals
** all writes in order to support rollback.  Locking is used to limit
** access to one or more reader or one writer.
**
** @(#) $Id: pager.c,v 1.9 2001/06/22 19:15:00 drh Exp $
*/
#include "sqliteInt.h"
#include "pager.h"
#include <fcntl.h>
#include <sys/stat.h>
#include <unistd.h>
#include <assert.h>
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}

/*
** Increment the reference count for a page.  If the page is
** currently on the freelist (the reference count is zero) then
** remove it from the freelist.
*/
static void sqlitepager_ref(PgHdr *pPg){

  if( pPg->nRef==0 ){
    /* The page is currently on the freelist.  Remove it. */
    if( pPg->pPrevFree ){
      pPg->pPrevFree->pNextFree = pPg->pNextFree;
    }else{
      pPg->pPager->pFirst = pPg->pNextFree;
    }
    if( pPg->pNextFree ){
      pPg->pNextFree->pPrevFree = pPg->pPrevFree;
    }else{
      pPg->pPager->pLast = pPg->pPrevFree;
    }
    pPg->pPager->nRef++;
  }
  pPg->nRef++;

}

/*
** Acquire a page.
**
** A read lock is obtained for the first page acquired.  The lock
** is dropped when the last page is released.  







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}

/*
** Increment the reference count for a page.  If the page is
** currently on the freelist (the reference count is zero) then
** remove it from the freelist.
*/
int sqlitepager_ref(void *pData){
  PgHdr *pPg = DATA_TO_PGHDR(pData);
  if( pPg->nRef==0 ){
    /* The page is currently on the freelist.  Remove it. */
    if( pPg->pPrevFree ){
      pPg->pPrevFree->pNextFree = pPg->pNextFree;
    }else{
      pPg->pPager->pFirst = pPg->pNextFree;
    }
    if( pPg->pNextFree ){
      pPg->pNextFree->pPrevFree = pPg->pPrevFree;
    }else{
      pPg->pPager->pLast = pPg->pPrevFree;
    }
    pPg->pPager->nRef++;
  }
  pPg->nRef++;
  return SQLITE_OK;
}

/*
** Acquire a page.
**
** A read lock is obtained for the first page acquired.  The lock
** is dropped when the last page is released.  
Changes to src/pager.h.
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**   http://www.hwaci.com/drh/
**
*************************************************************************
** This header file defines the interface that the sqlite page cache
** subsystem.  The page cache subsystem reads and writes a file a page
** at a time and provides a journal for rollback.
**
** @(#) $Id: pager.h,v 1.4 2001/05/24 21:06:36 drh Exp $
*/

/*
** The size of one page
*/
#define SQLITE_PAGE_SIZE 1024

/*
** The type used to represent a page number.  The first page in a file
** is called page 1.  0 is used to represent "not a page".
*/
typedef unsigned int Pgno;

/*
** Each open file is managed by a separate instance of the "Pager" structure.
*/
typedef struct Pager Pager;

int sqlitepager_open(Pager **ppPager,const char *zFilename,int nPage,int nEx);
void sqiltepager_set_destructor(Pager*, void(*)(void*));
int sqlitepager_close(Pager *pPager);
int sqlitepager_get(Pager *pPager, Pgno pgno, void **ppPage);
void *sqlitepager_lookup(Pager *pPager, Pgno pgno);

int sqlitepager_unref(void*);
Pgno sqlitepager_pagenumber(void*);
int sqlitepager_write(void*);
int sqlitepager_pagecount(Pager*);
int sqlitepager_commit(Pager*);
int sqlitepager_rollback(Pager*);
int *sqlitepager_stats(Pager*);







|



















|



>







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**   http://www.hwaci.com/drh/
**
*************************************************************************
** This header file defines the interface that the sqlite page cache
** subsystem.  The page cache subsystem reads and writes a file a page
** at a time and provides a journal for rollback.
**
** @(#) $Id: pager.h,v 1.5 2001/06/22 19:15:01 drh Exp $
*/

/*
** The size of one page
*/
#define SQLITE_PAGE_SIZE 1024

/*
** The type used to represent a page number.  The first page in a file
** is called page 1.  0 is used to represent "not a page".
*/
typedef unsigned int Pgno;

/*
** Each open file is managed by a separate instance of the "Pager" structure.
*/
typedef struct Pager Pager;

int sqlitepager_open(Pager **ppPager,const char *zFilename,int nPage,int nEx);
void sqlitepager_set_destructor(Pager*, void(*)(void*));
int sqlitepager_close(Pager *pPager);
int sqlitepager_get(Pager *pPager, Pgno pgno, void **ppPage);
void *sqlitepager_lookup(Pager *pPager, Pgno pgno);
int sqlitepager_ref(void*);
int sqlitepager_unref(void*);
Pgno sqlitepager_pagenumber(void*);
int sqlitepager_write(void*);
int sqlitepager_pagecount(Pager*);
int sqlitepager_commit(Pager*);
int sqlitepager_rollback(Pager*);
int *sqlitepager_stats(Pager*);
Changes to src/tclsqlite.c.
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** Author contact information:
**   drh@hwaci.com
**   http://www.hwaci.com/drh/
**
*************************************************************************
** A TCL Interface to SQLite
**
** $Id: tclsqlite.c,v 1.18 2001/04/15 00:37:09 drh Exp $
*/
#ifndef NO_TCL     /* Omit this whole file if TCL is unavailable */

#include "sqlite.h"
#include "tcl.h"
#include <stdlib.h>
#include <string.h>







|







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** Author contact information:
**   drh@hwaci.com
**   http://www.hwaci.com/drh/
**
*************************************************************************
** A TCL Interface to SQLite
**
** $Id: tclsqlite.c,v 1.19 2001/06/22 19:15:01 drh Exp $
*/
#ifndef NO_TCL     /* Omit this whole file if TCL is unavailable */

#include "sqlite.h"
#include "tcl.h"
#include <stdlib.h>
#include <string.h>
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  Tcl_FindExecutable(argv[0]);
  interp = Tcl_CreateInterp();
  Sqlite_Init(interp);
#ifdef SQLITE_TEST
  {
    extern int Sqlitetest1_Init(Tcl_Interp*);
    extern int Sqlitetest2_Init(Tcl_Interp*);

    Sqlitetest1_Init(interp);
    Sqlitetest2_Init(interp);

  }
#endif
  if( argc>=2 ){
    int i;
    Tcl_SetVar(interp,"argv0",argv[1],TCL_GLOBAL_ONLY);
    Tcl_SetVar(interp,"argv", "", TCL_GLOBAL_ONLY);
    for(i=2; i<argc; i++){







>


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  Tcl_FindExecutable(argv[0]);
  interp = Tcl_CreateInterp();
  Sqlite_Init(interp);
#ifdef SQLITE_TEST
  {
    extern int Sqlitetest1_Init(Tcl_Interp*);
    extern int Sqlitetest2_Init(Tcl_Interp*);
    extern int Sqlitetest3_Init(Tcl_Interp*);
    Sqlitetest1_Init(interp);
    Sqlitetest2_Init(interp);
    Sqlitetest3_Init(interp);
  }
#endif
  if( argc>=2 ){
    int i;
    Tcl_SetVar(interp,"argv0",argv[1],TCL_GLOBAL_ONLY);
    Tcl_SetVar(interp,"argv", "", TCL_GLOBAL_ONLY);
    for(i=2; i<argc; i++){
Changes to src/test3.c.
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**   http://www.hwaci.com/drh/
**
*************************************************************************
** Code for testing the btree.c module in SQLite.  This code
** is not included in the SQLite library.  It is used for automated
** testing of the SQLite library.
**
** $Id: test3.c,v 1.1 2001/06/02 02:40:57 drh Exp $
*/
#include "sqliteInt.h"
#include "pager.h"
#include "btree.h"
#include "tcl.h"
#include <stdlib.h>
#include <string.h>







|







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**   http://www.hwaci.com/drh/
**
*************************************************************************
** Code for testing the btree.c module in SQLite.  This code
** is not included in the SQLite library.  It is used for automated
** testing of the SQLite library.
**
** $Id: test3.c,v 1.2 2001/06/22 19:15:01 drh Exp $
*/
#include "sqliteInt.h"
#include "pager.h"
#include "btree.h"
#include "tcl.h"
#include <stdlib.h>
#include <string.h>
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*/
static int btree_open(
  void *NotUsed,
  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
  int argc,              /* Number of arguments */
  char **argv            /* Text of each argument */
){
  BTree *pBt;
  int nPage;
  int rc;
  char zBuf[100];
  if( argc!=2 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " FILENAME\"", 0);
    return TCL_ERROR;
  }







|
<







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*/
static int btree_open(
  void *NotUsed,
  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
  int argc,              /* Number of arguments */
  char **argv            /* Text of each argument */
){
  Btree *pBt;

  int rc;
  char zBuf[100];
  if( argc!=2 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " FILENAME\"", 0);
    return TCL_ERROR;
  }
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*/
static int btree_rollback(
  void *NotUsed,
  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
  int argc,              /* Number of arguments */
  char **argv            /* Text of each argument */
){
  Btree *pBt
  int rc;
  if( argc!=2 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " ID\"", 0);
    return TCL_ERROR;
  }
  if( Tcl_GetInt(interp, argv[1], (int*)&pBt) ) return TCL_ERROR;







|







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*/
static int btree_rollback(
  void *NotUsed,
  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
  int argc,              /* Number of arguments */
  char **argv            /* Text of each argument */
){
  Btree *pBt;
  int rc;
  if( argc!=2 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " ID\"", 0);
    return TCL_ERROR;
  }
  if( Tcl_GetInt(interp, argv[1], (int*)&pBt) ) return TCL_ERROR;
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*/
static int btree_drop_table(
  void *NotUsed,
  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
  int argc,              /* Number of arguments */
  char **argv            /* Text of each argument */
){
  Pager *pPager;
  int iTable;
  char zBuf[100];
  if( argc!=3 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " ID TABLENUM\"", 0);
    return TCL_ERROR;
  }
  if( Tcl_GetInt(interp, argv[1], (int*)&pBt) ) return TCL_ERROR;
  if( Tcl_GetInt(interp, argv[2], &iTable ) return TCL_ERROR;
  rc = sqliteBtreeDropTable(pBt, iTable);
  if( rc!=SQLITE_OK ){
    Tcl_AppendResult(interp, errorName(rc), 0);
    return TCL_ERROR;
  }
  return TCL_OK;
}

































































































































































































































































































































































































/*
** Register commands with the TCL interpreter.
*/
int Sqlitetest3_Init(Tcl_Interp *interp){
  Tcl_CreateCommand(interp, "btree_open", btree_open, 0, 0);
  Tcl_CreateCommand(interp, "btree_close", btree_close, 0, 0);
  Tcl_CreateCommand(interp, "btree_begin_transaction",
      btree_begin_transaction, 0, 0);
  Tcl_CreateCommand(interp, "btree_commit", btree_commit, 0, 0);
  Tcl_CreateCommand(interp, "btree_rollback", btree_rollback, 0, 0);
  Tcl_CreateCommand(interp, "btree_create_table", btree_create_table, 0, 0);
  Tcl_CreateCommand(interp, "btree_drop_table", btree_drop_table, 0, 0);












  return TCL_OK;
}







|

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*/
static int btree_drop_table(
  void *NotUsed,
  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
  int argc,              /* Number of arguments */
  char **argv            /* Text of each argument */
){
  Btree *pBt;
  int iTable;
  int rc;
  if( argc!=3 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " ID TABLENUM\"", 0);
    return TCL_ERROR;
  }
  if( Tcl_GetInt(interp, argv[1], (int*)&pBt) ) return TCL_ERROR;
  if( Tcl_GetInt(interp, argv[2], &iTable) ) return TCL_ERROR;
  rc = sqliteBtreeDropTable(pBt, iTable);
  if( rc!=SQLITE_OK ){
    Tcl_AppendResult(interp, errorName(rc), 0);
    return TCL_ERROR;
  }
  return TCL_OK;
}

/*
** Usage:   btree_get_meta ID
**
** Return meta data
*/
static int btree_get_meta(
  void *NotUsed,
  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
  int argc,              /* Number of arguments */
  char **argv            /* Text of each argument */
){
  Btree *pBt;
  int rc;
  int i;
  int aMeta[SQLITE_N_BTREE_META];
  if( argc!=2 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " ID\"", 0);
    return TCL_ERROR;
  }
  if( Tcl_GetInt(interp, argv[1], (int*)&pBt) ) return TCL_ERROR;
  rc = sqliteBtreeGetMeta(pBt, aMeta);
  if( rc!=SQLITE_OK ){
    Tcl_AppendResult(interp, errorName(rc), 0);
    return TCL_ERROR;
  }
  for(i=0; i<SQLITE_N_BTREE_META; i++){
    char zBuf[30];
    sprintf(zBuf,"%d",aMeta[i]);
    Tcl_AppendElement(interp, zBuf);
  }
  return TCL_OK;
}

/*
** Usage:   btree_update_meta ID METADATA...
**
** Return meta data
*/
static int btree_update_meta(
  void *NotUsed,
  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
  int argc,              /* Number of arguments */
  char **argv            /* Text of each argument */
){
  Btree *pBt;
  int rc;
  int i;
  int aMeta[SQLITE_N_BTREE_META];

  if( argc!=2+SQLITE_N_BTREE_META ){
    char zBuf[30];
    sprintf(zBuf,"%d",SQLITE_N_BTREE_META);
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " ID METADATA...\" (METADATA is ", zBuf, " integers)", 0);
    return TCL_ERROR;
  }
  if( Tcl_GetInt(interp, argv[1], (int*)&pBt) ) return TCL_ERROR;
  for(i=0; i<SQLITE_N_BTREE_META; i++){
    if( Tcl_GetInt(interp, argv[i+2], &aMeta[i]) ) return TCL_ERROR;
  }
  rc = sqliteBtreeUpdateMeta(pBt, aMeta);
  if( rc!=SQLITE_OK ){
    Tcl_AppendResult(interp, errorName(rc), 0);
    return TCL_ERROR;
  }
  return TCL_OK;
}

/*
** Usage:   btree_page_dump ID PAGENUM
**
** Print a disassembly of a page on standard output
*/
static int btree_page_dump(
  void *NotUsed,
  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
  int argc,              /* Number of arguments */
  char **argv            /* Text of each argument */
){
  Btree *pBt;
  int iPage;
  int rc;

  if( argc!=3 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " ID\"", 0);
    return TCL_ERROR;
  }
  if( Tcl_GetInt(interp, argv[1], (int*)&pBt) ) return TCL_ERROR;
  if( Tcl_GetInt(interp, argv[2], &iPage) ) return TCL_ERROR;
  rc = sqliteBtreePageDump(pBt, iPage);
  if( rc!=SQLITE_OK ){
    Tcl_AppendResult(interp, errorName(rc), 0);
    return TCL_ERROR;
  }
  return TCL_OK;
}

/*
** Usage:   btree_cursor ID TABLENUM
**
** Create a new cursor.  Return the ID for the cursor.
*/
static int btree_cursor(
  void *NotUsed,
  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
  int argc,              /* Number of arguments */
  char **argv            /* Text of each argument */
){
  Btree *pBt;
  int iTable;
  BtCursor *pCur;
  int rc;
  char zBuf[30];

  if( argc!=3 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " ID TABLENUM\"", 0);
    return TCL_ERROR;
  }
  if( Tcl_GetInt(interp, argv[1], (int*)&pBt) ) return TCL_ERROR;
  if( Tcl_GetInt(interp, argv[2], &iTable) ) return TCL_ERROR;
  rc = sqliteBtreeCursor(pBt, iTable, &pCur);
  if( rc ){
    Tcl_AppendResult(interp, errorName(rc), 0);
    return TCL_ERROR;
  }
  sprintf(zBuf,"0x%x", (int)pCur);
  Tcl_AppendResult(interp, zBuf, 0);
  return SQLITE_OK;
}

/*
** Usage:   btree_close_cursor ID
**
** Close a cursor opened using btree_cursor.
*/
static int btree_close_cursor(
  void *NotUsed,
  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
  int argc,              /* Number of arguments */
  char **argv            /* Text of each argument */
){
  BtCursor *pCur;
  int rc;

  if( argc!=2 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " ID\"", 0);
    return TCL_ERROR;
  }
  if( Tcl_GetInt(interp, argv[1], (int*)&pCur) ) return TCL_ERROR;
  rc = sqliteBtreeCloseCursor(pCur);
  if( rc ){
    Tcl_AppendResult(interp, errorName(rc), 0);
    return TCL_ERROR;
  }
  return SQLITE_OK;
}

/*
** Usage:   btree_move_to ID KEY
**
** Move the cursor to the entry with the given key.
*/
static int btree_move_to(
  void *NotUsed,
  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
  int argc,              /* Number of arguments */
  char **argv            /* Text of each argument */
){
  BtCursor *pCur;
  int rc;
  int res;
  char zBuf[20];

  if( argc!=3 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " ID KEY\"", 0);
    return TCL_ERROR;
  }
  if( Tcl_GetInt(interp, argv[1], (int*)&pCur) ) return TCL_ERROR;
  rc = sqliteBtreeMoveto(pCur, argv[2], strlen(argv[2]), &res);  
  if( rc ){
    Tcl_AppendResult(interp, errorName(rc), 0);
    return TCL_ERROR;
  }
  sprintf(zBuf,"%d",res);
  Tcl_AppendResult(interp, zBuf, 0);
  return SQLITE_OK;
}

/*
** Usage:   btree_delete ID
**
** Delete the entry that the cursor is pointing to
*/
static int btree_delete(
  void *NotUsed,
  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
  int argc,              /* Number of arguments */
  char **argv            /* Text of each argument */
){
  BtCursor *pCur;
  int rc;

  if( argc!=2 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " ID\"", 0);
    return TCL_ERROR;
  }
  if( Tcl_GetInt(interp, argv[1], (int*)&pCur) ) return TCL_ERROR;
  rc = sqliteBtreeDelete(pCur);
  if( rc ){
    Tcl_AppendResult(interp, errorName(rc), 0);
    return TCL_ERROR;
  }
  return SQLITE_OK;
}

/*
** Usage:   btree_insert ID KEY DATA
**
** Create a new entry with the given key and data.  If an entry already
** exists with the same key the old entry is overwritten.
*/
static int btree_insert(
  void *NotUsed,
  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
  int argc,              /* Number of arguments */
  char **argv            /* Text of each argument */
){
  BtCursor *pCur;
  int rc;

  if( argc!=4 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " ID KEY DATA\"", 0);
    return TCL_ERROR;
  }
  if( Tcl_GetInt(interp, argv[1], (int*)&pCur) ) return TCL_ERROR;
  rc = sqliteBtreeInsert(pCur, argv[2], strlen(argv[2]),
                         argv[3], strlen(argv[3]));
  if( rc ){
    Tcl_AppendResult(interp, errorName(rc), 0);
    return TCL_ERROR;
  }
  return SQLITE_OK;
}

/*
** Usage:   btree_next ID
**
** Move the cursor to the next entry in the table.
*/
static int btree_next(
  void *NotUsed,
  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
  int argc,              /* Number of arguments */
  char **argv            /* Text of each argument */
){
  BtCursor *pCur;
  int rc;

  if( argc!=2 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " ID\"", 0);
    return TCL_ERROR;
  }
  if( Tcl_GetInt(interp, argv[1], (int*)&pCur) ) return TCL_ERROR;
  rc = sqliteBtreeNext(pCur, 0);
  if( rc ){
    Tcl_AppendResult(interp, errorName(rc), 0);
    return TCL_ERROR;
  }
  return SQLITE_OK;
}

/*
** Usage:   btree_key ID
**
** Return the key for the entry at which the cursor is pointing.
*/
static int btree_key(
  void *NotUsed,
  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
  int argc,              /* Number of arguments */
  char **argv            /* Text of each argument */
){
  BtCursor *pCur;
  int rc;
  int n;
  char *zBuf;

  if( argc!=2 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " ID\"", 0);
    return TCL_ERROR;
  }
  if( Tcl_GetInt(interp, argv[1], (int*)&pCur) ) return TCL_ERROR;
  sqliteBtreeKeySize(pCur, &n);
  zBuf = malloc( n+1 );
  rc = sqliteBtreeKey(pCur, 0, n, zBuf);
  if( rc ){
    free(zBuf);
    Tcl_AppendResult(interp, errorName(rc), 0);
    return TCL_ERROR;
  }
  zBuf[n] = 0;
  Tcl_AppendResult(interp, zBuf, 0);
  free(zBuf);
  return SQLITE_OK;
}

/*
** Usage:   btree_data ID
**
** Return the data for the entry at which the cursor is pointing.
*/
static int btree_data(
  void *NotUsed,
  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
  int argc,              /* Number of arguments */
  char **argv            /* Text of each argument */
){
  BtCursor *pCur;
  int rc;
  int n;
  char *zBuf;

  if( argc!=2 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " ID\"", 0);
    return TCL_ERROR;
  }
  if( Tcl_GetInt(interp, argv[1], (int*)&pCur) ) return TCL_ERROR;
  sqliteBtreeDataSize(pCur, &n);
  zBuf = malloc( n+1 );
  rc = sqliteBtreeData(pCur, 0, n, zBuf);
  if( rc ){
    free(zBuf);
    Tcl_AppendResult(interp, errorName(rc), 0);
    return TCL_ERROR;
  }
  zBuf[n] = 0;
  Tcl_AppendResult(interp, zBuf, 0);
  free(zBuf);
  return SQLITE_OK;
}

/*
** Usage:   btree_cursor_dump ID
**
** Return two integers which are the page number and cell index for
** the given cursor.
*/
static int btree_cursor_dump(
  void *NotUsed,
  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
  int argc,              /* Number of arguments */
  char **argv            /* Text of each argument */
){
  BtCursor *pCur;
  int rc;
  int aResult[2];
  char zBuf[50];

  if( argc!=2 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " ID\"", 0);
    return TCL_ERROR;
  }
  if( Tcl_GetInt(interp, argv[1], (int*)&pCur) ) return TCL_ERROR;
  rc = sqliteBtreeCursorDump(pCur, aResult);
  if( rc ){
    Tcl_AppendResult(interp, errorName(rc), 0);
    return TCL_ERROR;
  }
  sprintf(zBuf,"%d %d",aResult[0], aResult[1]);
  Tcl_AppendResult(interp, zBuf, 0);
  return SQLITE_OK;
}

/*
** Register commands with the TCL interpreter.
*/
int Sqlitetest3_Init(Tcl_Interp *interp){
  Tcl_CreateCommand(interp, "btree_open", btree_open, 0, 0);
  Tcl_CreateCommand(interp, "btree_close", btree_close, 0, 0);
  Tcl_CreateCommand(interp, "btree_begin_transaction",
      btree_begin_transaction, 0, 0);
  Tcl_CreateCommand(interp, "btree_commit", btree_commit, 0, 0);
  Tcl_CreateCommand(interp, "btree_rollback", btree_rollback, 0, 0);
  Tcl_CreateCommand(interp, "btree_create_table", btree_create_table, 0, 0);
  Tcl_CreateCommand(interp, "btree_drop_table", btree_drop_table, 0, 0);
  Tcl_CreateCommand(interp, "btree_get_meta", btree_get_meta, 0, 0);
  Tcl_CreateCommand(interp, "btree_update_meta", btree_update_meta, 0, 0);
  Tcl_CreateCommand(interp, "btree_page_dump", btree_page_dump, 0, 0);
  Tcl_CreateCommand(interp, "btree_cursor", btree_cursor, 0, 0);
  Tcl_CreateCommand(interp, "btree_close_cursor", btree_close_cursor, 0, 0);
  Tcl_CreateCommand(interp, "btree_move_to", btree_move_to, 0, 0);
  Tcl_CreateCommand(interp, "btree_delete", btree_delete, 0, 0);
  Tcl_CreateCommand(interp, "btree_insert", btree_insert, 0, 0);
  Tcl_CreateCommand(interp, "btree_next", btree_next, 0, 0);
  Tcl_CreateCommand(interp, "btree_key", btree_key, 0, 0);
  Tcl_CreateCommand(interp, "btree_data", btree_data, 0, 0);
  Tcl_CreateCommand(interp, "btree_cursor_dump", btree_cursor_dump, 0, 0);
  return TCL_OK;
}