SQLite

/*
** 2004 April 6
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** $Id: btree.c,v 1.364 2007/05/02 01:34:31 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.

** later.
*/
static int fillInCell(
  MemPage *pPage,                /* The page that contains the cell */
  unsigned char *pCell,          /* Complete text of the cell */
  const void *pKey, i64 nKey,    /* The key */
  const void *pData,int nData,   /* The data */
  int nZero,                     /* Extra zero bytes to append to pData */
  int *pnSize                    /* Write cell size here */
){
  int nPayload;
  const u8 *pSrc;
  int nSrc, n, rc;
  int spaceLeft;
  MemPage *pOvfl = 0;

  /* Fill in the header. */
  nHeader = 0;
  if( !pPage->leaf ){
    nHeader += 4;
  }
  if( pPage->hasData ){
    nHeader += putVarint(&pCell[nHeader], nData+nZero);
  }else{
    nData = nZero = 0;
  }
  nHeader += putVarint(&pCell[nHeader], *(u64*)&nKey);
  parseCellPtr(pPage, pCell, &info);
  assert( info.nHeader==nHeader );
  assert( info.nKey==nKey );
  assert( info.nData==nData+nZero );
  
  /* Fill in the payload */
  nPayload = nData + nZero;
  if( pPage->intKey ){
    pSrc = pData;
    nSrc = nData;
    nData = 0;
  }else{
    nPayload += nKey;
    pSrc = pKey;

      pPrior = pOvfl->aData;
      put4byte(pPrior, 0);
      pPayload = &pOvfl->aData[4];
      spaceLeft = pBt->usableSize - 4;
    }
    n = nPayload;
    if( n>spaceLeft ) n = spaceLeft;
    if( nSrc>0 ){
      if( n>nSrc ) n = nSrc;
      assert( pSrc );
      memcpy(pPayload, pSrc, n);
    }else{
      memset(pPayload, 0, n);
    }
    nPayload -= n;
    pPayload += n;
    pSrc += n;
    nSrc -= n;
    spaceLeft -= n;
    if( nSrc==0 ){
      nSrc = nData;

  /* pPage is currently the right-child of pParent. Change this
  ** so that the right-child is the new page allocated above and
  ** pPage is the next-to-right child. 
  */
  assert( pPage->nCell>0 );
  parseCellPtr(pPage, findCell(pPage, pPage->nCell-1), &info);
  rc = fillInCell(pParent, parentCell, 0, info.nKey, 0, 0, 0, &parentSize);
  if( rc!=SQLITE_OK ){
    return rc;
  }
  assert( parentSize<64 );
  rc = insertCell(pParent, parentIdx, parentCell, parentSize, 0, 4);
  if( rc!=SQLITE_OK ){
    return rc;

        ** cell consists of the integer key for the right-most cell of 
        ** the sibling-page assembled above only.
        */
        CellInfo info;
        j--;
        parseCellPtr(pNew, apCell[j], &info);
        pCell = &aSpace[iSpace];
        fillInCell(pParent, pCell, 0, info.nKey, 0, 0, 0, &sz);
        iSpace += sz;
        assert( iSpace<=pBt->pageSize*5 );
        pTemp = 0;
      }else{
        pCell -= 4;
        pTemp = &aSpace[iSpace];
        iSpace += sz;

** For an INTKEY table, only the nKey value of the key is used.  pKey is
** ignored.  For a ZERODATA table, the pData and nData are both ignored.
*/
int sqlite3BtreeInsert(
  BtCursor *pCur,                /* Insert data into the table of this cursor */
  const void *pKey, i64 nKey,    /* The key of the new record */
  const void *pData, int nData,  /* The data of the new record */
  int nZero,                     /* Number of extra 0 bytes to append to data */
  int appendBias                 /* True if this is likely an append */
){
  int rc;
  int loc;
  int szNew;
  MemPage *pPage;
  BtShared *pBt = pCur->pBtree->pBt;

          pCur->pgnoRoot, nKey, nData, pPage->pgno,
          loc==0 ? "overwrite" : "new entry"));
  assert( pPage->isInit );
  rc = sqlite3PagerWrite(pPage->pDbPage);
  if( rc ) return rc;
  newCell = sqliteMallocRaw( MX_CELL_SIZE(pBt) );
  if( newCell==0 ) return SQLITE_NOMEM;
  rc = fillInCell(pPage, newCell, pKey, nKey, pData, nData, nZero, &szNew);
  if( rc ) goto end_insert;
  assert( szNew==cellSizePtr(pPage, newCell) );
  assert( szNew<=MX_CELL_SIZE(pBt) );
  if( loc==0 && CURSOR_VALID==pCur->eState ){
    int szOld;
    assert( pCur->idx>=0 && pCur->idx<pPage->nCell );
    oldCell = findCell(pPage, pCur->idx);

  nCopy = amt;
  if( nCopy>(nData-offset) ){
    nCopy = nData-offset;
  }
  if( nCopy>0 ){
    memcpy(&zData[offset], z, amt);
    rc = sqlite3BtreeInsert(pCsr, 0, iKey, zData, nData, 0, 0);
  }

  sqliteFree(zData);
  return rc;
}
#endif

**    May you share freely, never taking more than you give.
**
*************************************************************************
** This header file defines the interface that the sqlite B-Tree file
** subsystem.  See comments in the source code for a detailed description
** of what each interface routine does.
**
** @(#) $Id: btree.h,v 1.77 2007/05/02 01:34:31 drh Exp $
*/
#ifndef _BTREE_H_
#define _BTREE_H_

/* TODO: This definition is just included so other modules compile. It
** needs to be revisited.
*/

  void*
);

int sqlite3BtreeCloseCursor(BtCursor*);
int sqlite3BtreeMoveto(BtCursor*,const void *pKey,i64 nKey,int bias,int *pRes);
int sqlite3BtreeDelete(BtCursor*);
int sqlite3BtreeInsert(BtCursor*, const void *pKey, i64 nKey,
                                  const void *pData, int nData,
                                  int nZero, int bias);
int sqlite3BtreeFirst(BtCursor*, int *pRes);
int sqlite3BtreeLast(BtCursor*, int *pRes);
int sqlite3BtreeNext(BtCursor*, int *pRes);
int sqlite3BtreeEof(BtCursor*);
int sqlite3BtreeFlags(BtCursor*);
int sqlite3BtreePrevious(BtCursor*, int *pRes);
int sqlite3BtreeKeySize(BtCursor*, i64 *pSize);

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This header file defines the interface that the SQLite library
** presents to client programs.
**
** @(#) $Id: sqlite.h.in,v 1.203 2007/05/02 01:34:31 drh Exp $
*/
#ifndef _SQLITE3_H_
#define _SQLITE3_H_
#include <stdarg.h>     /* Needed for the definition of va_list */

/*
** Make sure we can call this stuff from C++.

int sqlite3_bind_double(sqlite3_stmt*, int, double);
int sqlite3_bind_int(sqlite3_stmt*, int, int);
int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite_int64);
int sqlite3_bind_null(sqlite3_stmt*, int);
int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*));
int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);

/*
** Return the number of host parameters in a compiled SQL statement.  This
** routine was added to support DBD::SQLite.
*/
int sqlite3_bind_parameter_count(sqlite3_stmt*);

void sqlite3_result_int64(sqlite3_context*, sqlite_int64);
void sqlite3_result_null(sqlite3_context*);
void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
void sqlite3_result_zeroblob(sqlite3_context*, int n);

/*
** These are the allowed values for the eTextRep argument to
** sqlite3_create_collation and sqlite3_create_function.
*/
#define SQLITE_UTF8           1
#define SQLITE_UTF16LE        2

**    May you share freely, never taking more than you give.
**
*************************************************************************
** Code for testing all sorts of SQLite interfaces.  This code
** is not included in the SQLite library.  It is used for automated
** testing of the SQLite library.
**
** $Id: test1.c,v 1.241 2007/05/02 01:34:31 drh Exp $
*/
#include "sqliteInt.h"
#include "tcl.h"
#include "os.h"
#include <stdlib.h>
#include <string.h>

  void *NotUsed,
  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
  int argc,              /* Number of arguments */
  char **argv            /* Text of each argument */
){
  return TCL_OK;         /* Do nothing */
}

/*
** Usage:   sqlite3_bind_zeroblob  STMT IDX N
**
** Test the sqlite3_bind_zeroblob interface.  STMT is a prepared statement.
** IDX is the index of a wildcard in the prepared statement.  This command
** binds a N-byte zero-filled BLOB to the wildcard.
*/
static int test_bind_zeroblob(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  sqlite3_stmt *pStmt;
  int idx;
  int n;
  int rc;

  if( objc!=4 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"",
        Tcl_GetStringFromObj(objv[0], 0), " STMT N VALUE", 0);
    return TCL_ERROR;
  }

  if( getStmtPointer(interp, Tcl_GetString(objv[1]), &pStmt) ) return TCL_ERROR;
  if( Tcl_GetIntFromObj(interp, objv[2], &idx) ) return TCL_ERROR;
  if( Tcl_GetIntFromObj(interp, objv[3], &n) ) return TCL_ERROR;

  rc = sqlite3_bind_zeroblob(pStmt, idx, n);
  if( sqlite3TestErrCode(interp, StmtToDb(pStmt), rc) ) return TCL_ERROR;
  if( rc!=SQLITE_OK ){
    return TCL_ERROR;
  }

  return TCL_OK;
}

/*
** Usage:   sqlite3_bind_int  STMT N VALUE
**
** Test the sqlite3_bind_int interface.  STMT is a prepared statement.
** N is the index of a wildcard in the prepared statement.  This command
** binds a 32-bit integer VALUE to that wildcard.

  static struct {
     char *zName;
     Tcl_ObjCmdProc *xProc;
     void *clientData;
  } aObjCmd[] = {
     { "sqlite3_connection_pointer",    get_sqlite_pointer, 0 },
     { "sqlite3_bind_int",              test_bind_int,      0 },
     { "sqlite3_bind_zeroblob",         test_bind_zeroblob, 0 },
     { "sqlite3_bind_int64",            test_bind_int64,    0 },
     { "sqlite3_bind_double",           test_bind_double,   0 },
     { "sqlite3_bind_null",             test_bind_null     ,0 },
     { "sqlite3_bind_text",             test_bind_text     ,0 },
     { "sqlite3_bind_text16",           test_bind_text16   ,0 },
     { "sqlite3_bind_blob",             test_bind_blob     ,0 },
     { "sqlite3_bind_parameter_count",  test_bind_parameter_count, 0},

**    May you share freely, never taking more than you give.
**
*************************************************************************
** 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 1.74 2007/05/02 01:34:32 drh Exp $
*/
#include "sqliteInt.h"
#include "pager.h"
#include "btree.h"
#include "tcl.h"
#include <stdlib.h>
#include <string.h>

    Tcl_AppendResult(interp, errorName(rc), 0);
    return TCL_ERROR;
  }
  return SQLITE_OK;
}

/*
** Usage:   btree_insert ID KEY DATA ?NZERO?
**
** 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 * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  BtCursor *pCur;
  int rc;
  int nZero;

  if( objc!=4 && objc!=5 ){
    Tcl_WrongNumArgs(interp, 1, objv, "ID KEY DATA ?NZERO?");
    return TCL_ERROR;
  }
  pCur = sqlite3TextToPtr(Tcl_GetString(objv[1]));
  if( objc==5 ){
    if( Tcl_GetIntFromObj(interp, objv[4], &nZero) ) return TCL_ERROR;
  }else{
    nZero = 0;
  }
  if( sqlite3BtreeFlags(pCur) & BTREE_INTKEY ){
    i64 iKey;
    int len;
    unsigned char *pBuf;
    if( Tcl_GetWideIntFromObj(interp, objv[2], &iKey) ) return TCL_ERROR;
    pBuf = Tcl_GetByteArrayFromObj(objv[3], &len);
    rc = sqlite3BtreeInsert(pCur, 0, iKey, pBuf, len, nZero, 0);
  }else{
    int keylen;
    int dlen;
    unsigned char *pKBuf;
    unsigned char *pDBuf;
    pKBuf = Tcl_GetByteArrayFromObj(objv[2], &keylen);
    pDBuf = Tcl_GetByteArrayFromObj(objv[3], &dlen);
    rc = sqlite3BtreeInsert(pCur, pKBuf, keylen, pDBuf, dlen, nZero, 0);
  }
  if( rc ){
    Tcl_AppendResult(interp, errorName(rc), 0);
    return TCL_ERROR;
  }
  return SQLITE_OK;
}

**
** Various scripts scan this source file in order to generate HTML
** documentation, headers files, or other derived files.  The formatting
** of the code in this file is, therefore, important.  See other comments
** in this file for details.  If in doubt, do not deviate from existing
** commenting and indentation practices when changing or adding code.
**
** $Id: vdbe.c,v 1.603 2007/05/02 01:34:32 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include "vdbeInt.h"

/*

        if( !pC->pData ) goto no_mem;
        memcpy(pC->pData, pTos->z, pC->nData);
        pC->pData[pC->nData] = 0;
        pC->pData[pC->nData+1] = 0;
      }
      pC->nullRow = 0;
    }else{
      int nZero;
      if( pTos->flags & MEM_Zero ){
        nZero = pTos->u.i;
      }else{
        nZero = 0;
      }
      rc = sqlite3BtreeInsert(pC->pCursor, 0, iKey,
                              pTos->z, pTos->n, nZero,
                              pOp->p2 & OPFLAG_APPEND);
    }
    
    pC->rowidIsValid = 0;
    pC->deferredMoveto = 0;
    pC->cacheStatus = CACHE_STALE;

  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=0 );
  assert( pTos->flags & MEM_Blob );
  if( (pCrsr = (pC = p->apCsr[i])->pCursor)!=0 ){
    int nKey = pTos->n;
    const char *zKey = pTos->z;
    assert( pC->isTable==0 );
    rc = sqlite3BtreeInsert(pCrsr, zKey, nKey, "", 0, 0, pOp->p2);
    assert( pC->deferredMoveto==0 );
    pC->cacheStatus = CACHE_STALE;
  }
  Release(pTos);
  pTos--;
  break;
}

*/
#define MEM_Term      0x0020   /* String rep is nul terminated */
#define MEM_Dyn       0x0040   /* Need to call sqliteFree() on Mem.z */
#define MEM_Static    0x0080   /* Mem.z points to a static string */
#define MEM_Ephem     0x0100   /* Mem.z points to an ephemeral string */
#define MEM_Short     0x0200   /* Mem.z points to Mem.zShort */
#define MEM_Agg       0x0400   /* Mem.z points to an agg function context */
#define MEM_Zero      0x0800   /* Mem.i contains count of 0s appended to blob */


/* A VdbeFunc is just a FuncDef (defined in sqliteInt.h) that contains
** additional information about auxiliary information bound to arguments
** of the function.  This is used to implement the sqlite3_get_auxdata()
** and sqlite3_set_auxdata() APIs.  The "auxdata" is some auxiliary data
** that can be associated with a constant argument to a function.  This

void sqlite3VdbeMemShallowCopy(Mem*, const Mem*, int);
int sqlite3VdbeMemMove(Mem*, Mem*);
int sqlite3VdbeMemNulTerminate(Mem*);
int sqlite3VdbeMemSetStr(Mem*, const char*, int, u8, void(*)(void*));
void sqlite3VdbeMemSetInt64(Mem*, i64);
void sqlite3VdbeMemSetDouble(Mem*, double);
void sqlite3VdbeMemSetNull(Mem*);
void sqlite3VdbeMemSetZeroBlob(Mem*,int);
int sqlite3VdbeMemMakeWriteable(Mem*);
int sqlite3VdbeMemDynamicify(Mem*);
int sqlite3VdbeMemStringify(Mem*, int);
i64 sqlite3VdbeIntValue(Mem*);
int sqlite3VdbeMemIntegerify(Mem*);
double sqlite3VdbeRealValue(Mem*);
void sqlite3VdbeIntegerAffinity(Mem*);

/**************************** sqlite3_value_  *******************************
** The following routines extract information from a Mem or sqlite3_value
** structure.
*/
const void *sqlite3_value_blob(sqlite3_value *pVal){
  Mem *p = (Mem*)pVal;
  if( p->flags & (MEM_Blob|MEM_Str) ){
    sqlite3VdbeMemExpandBlob(p);
    if( (p->flags & MEM_Term)==0 ){
      p->flags &= ~MEM_Str;
    }
    return p->z;
  }else{
    return sqlite3_value_text(pVal);
  }

  void (*xDel)(void *)
){
  sqlite3VdbeMemSetStr(&pCtx->s, z, n, SQLITE_UTF16LE, xDel);
}
#endif /* SQLITE_OMIT_UTF16 */
void sqlite3_result_value(sqlite3_context *pCtx, sqlite3_value *pValue){
  sqlite3VdbeMemCopy(&pCtx->s, pValue);
}
void sqlite3_result_zeroblob(sqlite3_context *pCtx, int n){
  sqlite3VdbeMemSetZeroBlob(&pCtx->s, n);
}


/*
** Execute the statement pStmt, either until a row of data is ready, the
** statement is completely executed or an error occurs.
**

  int rc;
  Vdbe *p = (Vdbe *)pStmt;
  rc = vdbeUnbind(p, i);
  if( rc==SQLITE_OK ){
    sqlite3VdbeMemCopy(&p->aVar[i-1], pValue);
  }
  return rc;
}
int sqlite3_bind_zeroblob(sqlite3_stmt *pStmt, int i, int n){
  int rc;
  Vdbe *p = (Vdbe *)pStmt;
  rc = vdbeUnbind(p, i);
  if( rc==SQLITE_OK ){
    sqlite3VdbeMemSetZeroBlob(&p->aVar[i-1], n);
  }
  return rc;
}

/*
** Return the number of wildcards that can be potentially bound to.
** This routine is added to support DBD::SQLite.  
*/
int sqlite3_bind_parameter_count(sqlite3_stmt *pStmt){

/*
** Make the given Mem object MEM_Dyn.
**
** Return SQLITE_OK on success or SQLITE_NOMEM if malloc fails.
*/
int sqlite3VdbeMemDynamicify(Mem *pMem){
  int n;
  u8 *z;
  sqlite3VdbeMemExpandBlob(pMem);
  if( (pMem->flags & (MEM_Ephem|MEM_Static|MEM_Short))==0 ){
    return SQLITE_OK;
  }
  assert( (pMem->flags & MEM_Dyn)==0 );
  n = pMem->n;
  assert( pMem->flags & (MEM_Str|MEM_Blob) );
  z = sqliteMallocRaw( n+2 );
  if( z==0 ){
    return SQLITE_NOMEM;
  }
  pMem->flags |= MEM_Dyn|MEM_Term;
  pMem->xDel = 0;
  memcpy(z, pMem->z, n );
  z[n] = 0;
  z[n+1] = 0;
  pMem->z = (char*)z;
  pMem->flags &= ~(MEM_Ephem|MEM_Static|MEM_Short);
  return SQLITE_OK;
}

/*
** If the given Mem* is a zero-filled blob, turn it into an ordinary
** blob stored in dynamically allocated space.
*/
int sqlite3VdbeMemExpandBlob(Mem *pMem){
  if( pMem->flags & MEM_Zero ){
    char *pNew;
    assert( (pMem->flags & MEM_Blob)!=0 );
    pNew = sqliteMalloc(pMem->n+pMem->u.i+1);
    if( pNew==0 ){ 
      return SQLITE_NOMEM;
    }
    memcpy(pNew, pMem->z, pMem->n);
    memset(&pNew[pMem->n], 0, pMem->u.i+1);
    sqlite3VdbeMemRelease(pMem);
    pMem->z = pNew;
    pMem->u.i = 0;
    pMem->flags &= MEM_Zero|MEM_Static|MEM_Ephem|MEM_Short;
    pMem->flags |= MEM_Term|MEM_Dyn;
  }
  return SQLITE_OK;
}


/*
** Make the given Mem object either MEM_Short or MEM_Dyn so that bytes
** of the Mem.z[] array can be modified.
**
** Return SQLITE_OK on success or SQLITE_NOMEM if malloc fails.
*/
int sqlite3VdbeMemMakeWriteable(Mem *pMem){
  int n;
  u8 *z;
  sqlite3VdbeMemExpandBlob(pMem);
  if( (pMem->flags & (MEM_Ephem|MEM_Static))==0 ){
    return SQLITE_OK;
  }
  assert( (pMem->flags & MEM_Dyn)==0 );
  assert( pMem->flags & (MEM_Str|MEM_Blob) );
  if( (n = pMem->n)+2<sizeof(pMem->zShort) ){
    z = (u8*)pMem->zShort;

*/
void sqlite3VdbeMemSetNull(Mem *pMem){
  sqlite3VdbeMemRelease(pMem);
  pMem->flags = MEM_Null;
  pMem->type = SQLITE_NULL;
  pMem->n = 0;
}

/*
** Delete any previous value and set the value to be a BLOB of length
** n containing all zeros.
*/
void sqlite3VdbeMemSetZeroBlob(Mem *pMem, int n){
  sqlite3VdbeMemRelease(pMem);
  pMem->flags = MEM_Blob|MEM_Zero;
  pMem->type = SQLITE_BLOB;
  pMem->n = 0;
  pMem->u.i = n;
}

/*
** Delete any previous value and set the value stored in *pMem to val,
** manifest type INTEGER.
*/
void sqlite3VdbeMemSetInt64(Mem *pMem, i64 val){
  sqlite3VdbeMemRelease(pMem);

/*
** Perform various checks on the memory cell pMem. An assert() will
** fail if pMem is internally inconsistent.
*/
void sqlite3VdbeMemSanity(Mem *pMem){
  int flags = pMem->flags;
  assert( flags!=0 );  /* Must define some type */
  if( flags & (MEM_Str|MEM_Blob) ){
    int x = flags & (MEM_Static|MEM_Dyn|MEM_Ephem|MEM_Short);
    assert( x!=0 );            /* Strings must define a string subtype */
    assert( (x & (x-1))==0 );  /* Only one string subtype can be defined */
    assert( pMem->z!=0 || x==MEM_Zero );      /* Strings must have a value */
    /* Mem.z points to Mem.zShort iff the subtype is MEM_Short */
    assert( (x & MEM_Short)==0 || pMem->z==pMem->zShort );
    assert( (x & MEM_Short)!=0 || pMem->z!=pMem->zShort );
    /* No destructor unless there is MEM_Dyn */
    assert( pMem->xDel==0 || (pMem->flags & MEM_Dyn)!=0 );

    if( (flags & MEM_Str) ){
      assert( pMem->enc==SQLITE_UTF8 || 
              pMem->enc==SQLITE_UTF16BE ||
              pMem->enc==SQLITE_UTF16LE 

  assert( (enc&3)==(enc&~SQLITE_UTF16_ALIGNED) );

  if( pVal->flags&MEM_Null ){
    return 0;
  }
  assert( (MEM_Blob>>3) == MEM_Str );
  pVal->flags |= (pVal->flags & MEM_Blob)>>3;
  sqlite3VdbeMemExpandBlob(pVal);
  if( pVal->flags&MEM_Str ){
    sqlite3VdbeChangeEncoding(pVal, enc & ~SQLITE_UTF16_ALIGNED);
    if( (enc & SQLITE_UTF16_ALIGNED)!=0 && 1==(1&(int)pVal->z) ){
      assert( (pVal->flags & (MEM_Ephem|MEM_Static))!=0 );
      if( sqlite3VdbeMemMakeWriteable(pVal)!=SQLITE_OK ){
        return 0;
      }

/*
** Return the number of bytes in the sqlite3_value object assuming
** that it uses the encoding "enc"
*/
int sqlite3ValueBytes(sqlite3_value *pVal, u8 enc){
  Mem *p = (Mem*)pVal;
  if( (p->flags & MEM_Blob)!=0 || sqlite3ValueText(pVal, enc) ){
    if( p->flags & MEM_Zero ){
      return p->n+p->u.i;
    }else{
      return p->n;
    }
  }
  return 0;
}

# 2007 May 01
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this script is btree database backend.
#
# $Id: btree9.test,v 1.1 2007/05/02 01:34:32 drh Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl

# The sqlite3BtreeInsert() API now has an additional "nZero" parameter
# which specifies the number of zero bytes to append to the end of the
# data.  This feature allows large zero-filled BLOBs to be created without
# having to allocate a big chunk of memory to instantiate the blob.
#
# The following code tests the new feature.
#

# Create the database
#
do_test btree9-1.1 {
  file delete -force test1.bt
  file delete -force test1.bt-journal
  set b1 [btree_open test1.bt 2000 0]
  btree_begin_transaction $b1
  set t1 [btree_create_table $b1 5]
  set c1 [btree_cursor $b1 $t1 1]
  btree_insert $c1 1 data-for-1 20000
  btree_move_to $c1 1
  btree_key $c1
} {1}
do_test btree9-1.2 {
  btree_payload_size $c1
} {20010}


btree_close_cursor $c1
btree_commit $b1
btree_close $b1

finish_test