SQLite4  Check-in [610033d7f5]

  int regTabname = iMem++;     /* Register containing table name */
  int regIdxname = iMem++;     /* Register containing index name */
  int regStat1 = iMem++;       /* The stat column of sqlite_stat1 */
#ifdef SQLITE4_ENABLE_STAT3
  int regNumEq = regStat1;     /* Number of instances.  Same as regStat1 */
  int regNumLt = iMem++;       /* Number of keys less than regSample */
  int regNumDLt = iMem++;      /* Number of distinct keys less than regSample */
#endif
  int regSample = iMem++;      /* The next sample value */
#ifdef SQLITE4_ENABLE_STAT3
  int regAccum = iMem++;       /* Register to hold Stat3Accum object */
  int regLoop = iMem++;        /* Loop counter */
  int regCount = iMem++;       /* Number of rows in the table or index */
  int regTemp1 = iMem++;       /* Intermediate register */
  int regTemp2 = iMem++;       /* Intermediate register */
  int regNewSample = iMem++;
  int once = 1;                /* One-time initialization */

**
** This routine is not threadsafe.  It should be called from a single
** thread to initialized the library in a multi-threaded system.  Other
** threads should avoid using the sqlite4_env object until after it has
** completely initialized.
*/
int sqlite4_initialize(sqlite4_env *pEnv){
  MUTEX_LOGIC( sqlite4_mutex *pMaster; )       /* The main static mutex */
  int rc;                                      /* Result code */

  if( pEnv==0 ) pEnv = &sqlite4DefaultEnv;

  /* If SQLite is already completely initialized, then this call
  ** to sqlite4_initialize() should be a no-op.  But the initialization
  ** must be complete.  So isInit must not be set until the very end

}

/*
** Set the output variable to the number of KB of data written into the
** database file since the most recent checkpoint.
*/
int lsmCheckpointSize(lsm_db *db, int *pnKB){
  ShmHeader *pShm = db->pShmhdr;
  int rc = LSM_OK;
  u32 nSynced;

  /* Set nSynced to the number of pages that had been written when the 
  ** database was last checkpointed. */
  rc = lsmCheckpointSynced(db, 0, 0, &nSynced);

  if( rc==LSM_OK ){
    u32 nPgsz = db->pShmhdr->aSnap1[CKPT_HDR_PGSZ];
    u32 nWrite = db->pShmhdr->aSnap1[CKPT_HDR_NWRITE];
    *pnKB = (int)(( ((i64)(nWrite - nSynced) * nPgsz) + 1023) / 1024);
  }

  return rc;
}

    const int nPagePerBlock = (pFS->nBlocksize / pFS->nPagesize);
    int nSz = pFS->nPagesize;
    u8 *aBuf = 0;
    u8 *aData = 0;

    for(i=0; rc==LSM_OK && i<nPagePerBlock; i++){
      i64 iOff = iFromOff + i*nSz;
      Page *pPg;

      /* Set aData to point to a buffer containing the from page */
      if( (iOff+nSz)<=pFS->nMapLimit ){
        u8 *aMap = (u8 *)(pFS->pMap);
        aData = &aMap[iOff];
      }else{
        if( aBuf==0 ){

    pCsr->nPtr = iPtr;
  }
}

static int multiCursorAddAll(MultiCursor *pCsr, Snapshot *pSnap){
  Level *pLvl;
  int nPtr = 0;
  int iPtr = 0;
  int rc = LSM_OK;

  for(pLvl=pSnap->pLevel; pLvl; pLvl=pLvl->pNext){
    /* If the LEVEL_INCOMPLETE flag is set, then this function is being
    ** called (indirectly) from within a sortedNewToplevel() call to
    ** construct pLvl. In this case ignore pLvl - this cursor is going to
    ** be used to retrieve a freelist entry from the LSM, and the partially

*/
static int mergeWorkerPushHierarchy(
  MergeWorker *pMW,               /* Merge worker object */
  int iTopic,                     /* Topic value for this key */
  void *pKey,                     /* Pointer to key buffer */
  int nKey                        /* Size of pKey buffer in bytes */
){
  lsm_db *pDb = pMW->pDb;         /* Database handle */
  int rc = LSM_OK;                /* Return Code */
  int iLevel;                     /* Level of b-tree hierachy to write to */
  int nData;                      /* Size of aData[] in bytes */
  u8 *aData;                      /* Page data for level iLevel */
  int iOff;                       /* Offset on b-tree page to write record to */
  int nRec;                       /* Initial number of records on b-tree page */
  Pgno iPtr;                      /* Pointer value to accompany pKey/nKey */

  assert( pMW->aSave[0].bStore==0 );
  assert( pMW->aSave[1].bStore==0 );
  rc = mergeWorkerBtreeIndirect(pMW);

  /* Obtain the absolute pointer value to store along with the key in the

static int mergeWorkerNextPage(
  MergeWorker *pMW,               /* Merge worker object to append page to */
  Pgno iFPtr                      /* Pointer value for footer of new page */
){
  int rc = LSM_OK;                /* Return code */
  Page *pNext = 0;                /* New page appended to run */
  lsm_db *pDb = pMW->pDb;         /* Database handle */
  Segment *pSeg;                  /* Run to append to */

  rc = lsmFsSortedAppend(pDb->pFS, pDb->pWorker, pMW->pLevel, 0, &pNext);
  assert( rc || pMW->pLevel->lhs.iFirst>0 || pMW->pDb->compress.xCompress );

  if( rc==LSM_OK ){
    u8 *aData;                    /* Data buffer belonging to page pNext */
    int nData;                    /* Size of aData[] in bytes */

/*
** Free all resources allocated by mergeWorkerInit().
*/
static void mergeWorkerShutdown(MergeWorker *pMW, int *pRc){
  int i;                          /* Iterator variable */
  int rc = *pRc;
  MultiCursor *pCsr = pMW->pCsr;
  Hierarchy *p = &pMW->hier;

  /* Unless the merge has finished, save the cursor position in the
  ** Merge.aInput[] array. See function mergeWorkerInit() for the 
  ** code to restore a cursor position based on aInput[].  */
  if( rc==LSM_OK && pCsr && lsmMCursorValid(pCsr) ){
    Merge *pMerge = pMW->pLevel->pMerge;
    int bBtree = (pCsr->pBtCsr!=0);

static int mergeWorkerStep(MergeWorker *pMW){
  lsm_db *pDb = pMW->pDb;       /* Database handle */
  MultiCursor *pCsr;            /* Cursor to read input data from */
  int rc = LSM_OK;              /* Return code */
  int eType;                    /* SORTED_SEPARATOR, WRITE or DELETE */
  void *pKey; int nKey;         /* Key */
  Segment *pSeg;                /* Output segment */
  Pgno iPtr;
  int iVal;

  pCsr = pMW->pCsr;
  pSeg = &pMW->pLevel->lhs;

  /* Pull the next record out of the source cursor. */
  lsmMCursorKey(pCsr, &pKey, &nKey);
  eType = pCsr->eType;

  if( eType & LSM_SYSTEMKEY ){
    int i;
    i = 1;
  }

  /* Figure out if the output record may have a different pointer value
  ** than the previous. This is the case if the current key is identical to
  ** a key that appears in the lowest level run being merged. If so, set 
  ** iPtr to the absolute pointer value. If not, leave iPtr set to zero, 
  ** indicating that the output pointer value should be a copy of the pointer 
  ** value written with the previous key.  */
  iPtr = (pCsr->pPrevMergePtr ? *pCsr->pPrevMergePtr : 0);

static void assertIsWorkingChild(
  lsm_db *db, 
  TreeNode *pNode, 
  TreeNode *pParent, 
  int iCell
){
  TreeNode *p;
  int rc = LSM_OK;
  u32 iPtr = getChildPtr(pParent, WORKING_VERSION, iCell);
  p = treeShmptr(db, iPtr);
  assert( p==pNode );
}
#else
# define assertIsWorkingChild(w,x,y,z)
#endif

*/
static TreeKey *csrGetKey(TreeCursor *pCsr, TreeBlob *pBlob, int *pRc){
  TreeKey *pRet;
  lsm_db *pDb = pCsr->pDb;
  u32 iPtr = pCsr->apTreeNode[pCsr->iNode]->aiKeyPtr[pCsr->aiCell[pCsr->iNode]];

  assert( iPtr );
  pRet = treeShmptrUnsafe(pDb, iPtr);
  if( !(pRet->flags & LSM_CONTIGUOUS) ){
    pRet = treeShmkey(pDb, iPtr, TKV_LOADVAL, pBlob, pRc);
  }

  return pRet;
}

** If either of the conditions are untrue, LSM_CORRUPT is returned. Or, if
** an error is encountered before the checks are completed, another LSM error
** code (i.e. LSM_IOERR or LSM_NOMEM) may be returned.
*/
static int treeCheckLinkedList(lsm_db *db){
  int rc = LSM_OK;
  int nVisit = 0;
  u32 iShmid;
  ShmChunk *p;

  p = treeShmChunkRc(db, db->treehdr.iFirst, &rc);
  iShmid = p->iShmid;
  while( rc==LSM_OK && p ){
    if( p->iNext ){
      if( p->iNext>=db->treehdr.nChunk ){
        rc = LSM_CORRUPT_BKPT;
      }else{
        ShmChunk *pNext = treeShmChunkRc(db, p->iNext, &rc);
        if( rc==LSM_OK ){

      pCsr->iNode--;
      treeUpdatePtr(db, pCsr, iNew);
    }
  }
}

static int treeNextIsEndDelete(lsm_db *db, TreeCursor *pCsr){
  TreeNode *pNode;
  int iNode = pCsr->iNode;
  int iCell = pCsr->aiCell[iNode]+1;

  /* Cursor currently points to a leaf node. */
  assert( pCsr->iNode==(db->treehdr.root.nHeight-1) );

  while( iNode>=0 ){

    iCell = pCsr->aiCell[iNode];
  }

  return 0;
}

static int treePrevIsStartDelete(lsm_db *db, TreeCursor *pCsr){
  TreeNode *pNode;
  int iNode = pCsr->iNode;

  /* Cursor currently points to a leaf node. */
  assert( pCsr->iNode==(db->treehdr.root.nHeight-1) );

  while( iNode>=0 ){
    TreeNode *pNode = pCsr->apTreeNode[iNode];

      pNode = (TreeNode *)treeShmptrUnsafe(pDb, iNodePtr);
      iNode++;
      pCsr->apTreeNode[iNode] = pNode;

      /* Compare (pKey/nKey) with the key in the middle slot of B-tree node
      ** pNode. The middle slot is never empty. If the comparison is a match,
      ** then the search is finished. Break out of the loop. */
      pTreeKey = treeShmptrUnsafe(pDb, pNode->aiKeyPtr[1]);
      if( !(pTreeKey->flags & LSM_CONTIGUOUS) ){
        pTreeKey = treeShmkey(pDb, pNode->aiKeyPtr[1], TKV_LOADKEY, &b, &rc);
        if( rc!=LSM_OK ) break;
      }
      res = treeKeycmp((void *)&pTreeKey[1], pTreeKey->nKey, pKey, nKey);
      if( res==0 ){
        pCsr->aiCell[iNode] = 1;
        break;
      }

      /* Based on the results of the previous comparison, compare (pKey/nKey)
      ** to either the left or right key of the B-tree node, if such a key
      ** exists. */
      iTest = (res>0 ? 0 : 2);
      iTreeKey = pNode->aiKeyPtr[iTest];
      if( iTreeKey ){
        pTreeKey = treeShmptrUnsafe(pDb, iTreeKey);
        if( !(pTreeKey->flags & LSM_CONTIGUOUS) ){
          pTreeKey = treeShmkey(pDb, iTreeKey, TKV_LOADKEY, &b, &rc);
          if( rc ) break;
        }
        res = treeKeycmp((void *)&pTreeKey[1], pTreeKey->nKey, pKey, nKey);
        if( res==0 ){
          pCsr->aiCell[iNode] = iTest;

*/
void sqlite4_profile(
  sqlite4 *db,
  void *pArg,
  void (*xProfile)(void*,const char*,sqlite4_uint64),
  void (*xDestroy)(void*)
){
  void *pOld;
  sqlite4_mutex_enter(db->mutex);
  if( db->xProfileDestroy ){
    db->xProfileDestroy(db->pProfileArg);
  }
  db->xProfile = xProfile;
  db->xProfileDestroy = xDestroy;
  db->pProfileArg = pArg;
  sqlite4_mutex_leave(db->mutex);
}
#endif /* SQLITE4_OMIT_TRACE */

/*
** This function returns true if main-memory should be used instead of
** a temporary file for transient pager files and statement journals.
** The value returned depends on the value of db->temp_store (runtime
** parameter) and the compile time value of SQLITE4_TEMP_STORE. The
** following table describes the relationship between these two values
** and this functions return value.
**
**   SQLITE4_TEMP_STORE     db->temp_store     Location of temporary database
**   -----------------     --------------     ------------------------------
**   0                     any                file      (return 0)
**   1                     1                  file      (return 0)
**   1                     2                  memory    (return 1)
**   1                     0                  file      (return 0)
**   2                     1                  file      (return 0)
**   2                     2                  memory    (return 1)
**   2                     0                  memory    (return 1)
**   3                     any                memory    (return 1)
*/
int sqlite4TempInMemory(const sqlite4 *db){
#if SQLITE4_TEMP_STORE==1
  return ( db->temp_store==2 );
#endif
#if SQLITE4_TEMP_STORE==2
  return ( db->temp_store!=1 );
#endif
#if SQLITE4_TEMP_STORE==3
  return 1;
#endif
#if SQLITE4_TEMP_STORE<1 || SQLITE4_TEMP_STORE>3
  return 0;
#endif
}

/*
** Return UTF-8 encoded English language explanation of the most recent
** error.
*/
const char *sqlite4_errmsg(sqlite4 *db){
  const char *z;
  if( !db ){

static int debugMutexEnd(void *p){ UNUSED_PARAMETER(p); return SQLITE4_OK; }

/*
** The sqlite4_mutex_alloc() routine allocates a new
** mutex and returns a pointer to it.  If it returns NULL
** that means that a mutex could not be allocated. 
*/
static sqlite4_mutex *debugMutexAlloc(sqlite4_env *pEnv, int id){

  sqlite4DebugMutex *pNew = 0;
  pNew = sqlite4Malloc(pEnv, sizeof(*pNew));
  if( pNew ){
    pNew->id = id;
    pNew->cnt = 0;
    pNew->pEnv = pEnv;
  }

#include "hash.h"
#include "parse.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <stddef.h>


/*
** If compiling for a processor that lacks floating point support,
** substitute integer for floating-point
*/
#ifdef SQLITE4_OMIT_FLOATING_POINT
# define double sqlite4_int64

typedef struct SrcListItem SrcListItem;
typedef struct StrAccum StrAccum;
typedef struct Table Table;
typedef struct Token Token;
typedef struct Trigger Trigger;
typedef struct TriggerPrg TriggerPrg;
typedef struct TriggerStep TriggerStep;
typedef struct UnpackedRecord UnpackedRecord;
typedef struct VTable VTable;
typedef struct VtabCtx VtabCtx;
typedef struct Walker Walker;
typedef struct WherePlan WherePlan;
typedef struct WhereInfo WhereInfo;
typedef struct WhereLevel WhereLevel;

  u16 nField;         /* Total number of entries in aColl[] */
  u16 nPK;            /* Number of primary key entries at the end of aColl[] */
  u16 nData;          /* Number of columns of data in KV entry value */
  u8 *aSortOrder;     /* Sort order for each column.  May be NULL */
  CollSeq *aColl[1];  /* Collating sequence for each term of the key */
};

/*
** An instance of the following structure holds information about a
** single index record that has already been parsed out into individual
** values.
**
** A record is an object that contains one or more fields of data.
** Records are used to store the content of a table row and to store
** the key of an index.  A blob encoding of a record is created by
** the OP_MakeRecord opcode of the VDBE and is disassembled by the
** OP_Column opcode.
**
** This structure holds a record that has already been disassembled
** into its constituent fields.
*/
struct UnpackedRecord {
  KeyInfo *pKeyInfo;  /* Collation and sort-order information */
  u16 nField;         /* Number of entries in apMem[] */
  u8 flags;           /* Boolean settings.  UNPACKED_... below */
  i64 rowid;          /* Used by UNPACKED_PREFIX_SEARCH */
  Mem *aMem;          /* Values */
};

/*
** Allowed values of UnpackedRecord.flags
*/
#define UNPACKED_INCRKEY       0x01  /* Make this key an epsilon larger */
#define UNPACKED_PREFIX_MATCH  0x02  /* A prefix match is considered OK */
#define UNPACKED_PREFIX_SEARCH 0x04  /* Ignore final (rowid) field */

/*
** Each SQL index is represented in memory by an
** instance of the following structure.
**
** The columns of the table that are to be indexed are described
** by the aiColumn[] field of this structure.  For example, suppose
** we have the following table and index:

** SQLITE4_ENABLE_FTS3 macro.  But to avoid confusion we also all
** the SQLITE4_ENABLE_FTS4 macro to serve as an alisse for SQLITE4_ENABLE_FTS3.
*/
#if defined(SQLITE4_ENABLE_FTS4) && !defined(SQLITE4_ENABLE_FTS3)
# define SQLITE4_ENABLE_FTS3
#endif

/*
** The ctype.h header is needed for non-ASCII systems.  It is also
** needed by FTS3 when FTS3 is included in the amalgamation.
*/
#if !defined(SQLITE4_ASCII) || \
    (defined(SQLITE4_ENABLE_FTS3) && defined(SQLITE4_AMALGAMATION))
# include <ctype.h>
#endif

/*
** The following macros mimic the standard library functions toupper(),
** isspace(), isalnum(), isdigit() and isxdigit(), respectively. The
** sqlite versions only work for ASCII characters, regardless of locale.
*/
#ifdef SQLITE4_ASCII

int sqlite4RunVacuum(char**, sqlite4*);
char *sqlite4NameFromToken(sqlite4*, Token*);
int sqlite4ExprCompare(Expr*, Expr*);
int sqlite4ExprListCompare(ExprList*, ExprList*);
void sqlite4ExprAnalyzeAggregates(NameContext*, Expr*);
void sqlite4ExprAnalyzeAggList(NameContext*,ExprList*);
Vdbe *sqlite4GetVdbe(Parse*);
void sqlite4PrngSaveState(void);
void sqlite4PrngRestoreState(void);
void sqlite4PrngResetState(void);
void sqlite4CodeVerifySchema(Parse*, int);
void sqlite4CodeVerifyNamedSchema(Parse*, const char *zDb);
void sqlite4BeginTransaction(Parse*, int);
void sqlite4EndTransaction(Parse *, int);
void sqlite4Savepoint(Parse*, int, Token*);
void sqlite4CloseSavepoints(sqlite4 *);
int sqlite4ExprIsConstant(Expr*);

void sqlite4Detach(Parse*, Expr*);
int sqlite4FixInit(DbFixer*, Parse*, int, const char*, const Token*);
int sqlite4FixSrcList(DbFixer*, SrcList*);
int sqlite4FixSelect(DbFixer*, Select*);
int sqlite4FixExpr(DbFixer*, Expr*);
int sqlite4FixExprList(DbFixer*, ExprList*);
int sqlite4FixTriggerStep(DbFixer*, TriggerStep*);
int sqlite4AtoF(const char *z, double*, int, u8);
int sqlite4GetInt32(const char *, int*);
int sqlite4Atoi(const char*);
int sqlite4Utf16ByteLen(const void *pData, int nChar);
int sqlite4Utf8CharLen(const char *pData, int nByte);
u32 sqlite4Utf8Read(const char*, const char**);

/*

extern const unsigned char sqlite4OpcodeProperty[];
extern const unsigned char sqlite4UpperToLower[];
extern const unsigned char sqlite4CtypeMap[];
extern const Token sqlite4IntTokens[];
extern struct sqlite4_env sqlite4DefaultEnv;
extern struct KVFactory sqlite4BuiltinFactory;
#endif
void sqlite4RootPageMoved(sqlite4*, int, int, int);
void sqlite4Reindex(Parse*, Token*, Token*);
void sqlite4AlterFunctions(sqlite4_env*);
void sqlite4AlterRenameTable(Parse*, SrcList*, Token*);
int sqlite4GetToken(const unsigned char *, int *);
void sqlite4NestedParse(Parse*, const char*, ...);
void sqlite4ExpirePreparedStatements(sqlite4*);
int sqlite4CodeSubselect(Parse *, Expr *, int, int);

void *sqlite4ParserAlloc(void*(*)(void*,size_t), void*);
void sqlite4ParserFree(void*, void(*)(void*,void*));
void sqlite4Parser(void*, int, Token, Parse*);
#ifdef YYTRACKMAXSTACKDEPTH
  int sqlite4ParserStackPeak(void*);
#endif

void sqlite4AutoLoadExtensions(sqlite4*);
#ifndef SQLITE4_OMIT_LOAD_EXTENSION
  void sqlite4CloseExtensions(sqlite4*);
#else
# define sqlite4CloseExtensions(X)
#endif

#ifdef SQLITE4_TEST
  int sqlite4Utf8To8(char*);
#endif

#ifdef SQLITE4_OMIT_VIRTUALTABLE
#  define sqlite4VtabClear(Y)
#  define sqlite4VtabSync(X,Y) SQLITE4_OK

FuncDef *sqlite4VtabOverloadFunction(sqlite4 *,FuncDef*, int nArg, Expr*);
void sqlite4InvalidFunction(sqlite4_context*,int,sqlite4_value**);
int sqlite4VdbeParameterIndex(Vdbe*, const char*, int);
int sqlite4TransferBindings(sqlite4_stmt *, sqlite4_stmt *);
int sqlite4Reprepare(Vdbe*);
void sqlite4ExprListCheckLength(Parse*, ExprList*, const char*);
CollSeq *sqlite4BinaryCompareCollSeq(Parse *, Expr *, Expr *);
int sqlite4TempInMemory(const sqlite4*);
const char *sqlite4JournalModename(int);
int sqlite4Checkpoint(sqlite4*, int, int, int*, int*);
int sqlite4WalDefaultHook(void*,sqlite4*,const char*,int);

/* Declarations for functions in fkey.c. All of these are replaced by
** no-op macros if OMIT_FOREIGN_KEY is defined. In this case no foreign
** key functionality is available. If OMIT_TRIGGER is defined but
** OMIT_FOREIGN_KEY is not, only some of the functions are no-oped. In
** this case foreign keys are parsed, but no other functionality is 
** provided (enforcement of FK constraints requires the triggers sub-system).

sqlite4_value *sqlite4VdbeGetValue(Vdbe*, int, u8);
void sqlite4VdbeSetVarmask(Vdbe*, int);
#ifndef SQLITE4_OMIT_TRACE
  char *sqlite4VdbeExpandSql(Vdbe*, const char*);
#endif
sqlite4_value *sqlite4ColumnValue(sqlite4_stmt *pStmt, int iCol);

void sqlite4VdbeRecordUnpack(KeyInfo*,int,const void*,UnpackedRecord*);
UnpackedRecord *sqlite4VdbeAllocUnpackedRecord(KeyInfo *, char *, int, char **);

#ifndef SQLITE4_OMIT_TRIGGER
void sqlite4VdbeLinkSubProgram(Vdbe *, SubProgram *);
#endif


#ifndef NDEBUG
  void sqlite4VdbeComment(Vdbe*, const char*, ...);

** Function prototypes
*/
void sqlite4VdbeFreeCursor(Vdbe *, VdbeCursor*);
void sqliteVdbePopStack(Vdbe*,int);
#if defined(SQLITE4_DEBUG) || defined(VDBE_PROFILE)
void sqlite4VdbePrintOp(FILE*, int, Op*);
#endif
u32 sqlite4VdbeSerialTypeLen(u32);
u32 sqlite4VdbeSerialType(Mem*, int);
u32 sqlite4VdbeSerialPut(unsigned char*, int, Mem*, int);
u32 sqlite4VdbeSerialGet(const unsigned char*, u32, Mem*);
void sqlite4VdbeDeleteAuxData(VdbeFunc*, int);

int sqlite4VdbeCreateDecoder(
  sqlite4 *db,                /* The database connection */
  const unsigned char *aIn,   /* The input data blob */
  int nIn,                    /* Number of bytes in aIn[] */
  int mxCol,                  /* Maximum number of columns in aIn[] */

  return u.r;
}
# define swapMixedEndianFloat(X)  X = floatSwap(X)
#else
# define swapMixedEndianFloat(X)
#endif


/*
** This routine is used to allocate sufficient space for an UnpackedRecord
** structure large enough to be used with sqlite4VdbeRecordUnpack() if
** the first argument is a pointer to KeyInfo structure pKeyInfo.
**
** The space is either allocated using sqlite4DbMallocRaw() or from within
** the unaligned buffer passed via the second and third arguments (presumably
** stack space). If the former, then *ppFree is set to a pointer that should
** be eventually freed by the caller using sqlite4DbFree(). Or, if the 
** allocation comes from the pSpace/szSpace buffer, *ppFree is set to NULL
** before returning.
**
** If an OOM error occurs, NULL is returned.
*/
UnpackedRecord *sqlite4VdbeAllocUnpackedRecord(
  KeyInfo *pKeyInfo,              /* Description of the record */
  char *pSpace,                   /* Unaligned space available */
  int szSpace,                    /* Size of pSpace[] in bytes */
  char **ppFree                   /* OUT: Caller should free this pointer */
){
  UnpackedRecord *p;              /* Unpacked record to return */
  int nOff;                       /* Increment pSpace by nOff to align it */
  int nByte;                      /* Number of bytes required for *p */

  /* We want to shift the pointer pSpace up such that it is 8-byte aligned.
  ** Thus, we need to calculate a value, nOff, between 0 and 7, to shift 
  ** it by.  If pSpace is already 8-byte aligned, nOff should be zero.
  */
  nOff = (8 - (SQLITE4_PTR_TO_INT(pSpace) & 7)) & 7;
  nByte = ROUND8(sizeof(UnpackedRecord)) + sizeof(Mem)*(pKeyInfo->nField+1);
  if( nByte>szSpace+nOff ){
    p = (UnpackedRecord *)sqlite4DbMallocRaw(pKeyInfo->db, nByte);
    *ppFree = (char *)p;
    if( !p ) return 0;
  }else{
    p = (UnpackedRecord*)&pSpace[nOff];
    *ppFree = 0;
  }

  p->aMem = (Mem*)&((char*)p)[ROUND8(sizeof(UnpackedRecord))];
  p->pKeyInfo = pKeyInfo;
  p->nField = pKeyInfo->nField + 1;
  return p;
}


/*
** This routine sets the value to be returned by subsequent calls to
** sqlite4_changes() on the database handle 'db'. 
*/
void sqlite4VdbeSetChanges(sqlite4 *db, int nChange){
  assert( sqlite4_mutex_held(db->mutex) );

        }
        /* Loop through table entries that match term pOrTerm. */
        pSubWInfo = sqlite4WhereBegin(pParse, pOrTab, pOrExpr, 0, 0,
                        WHERE_OMIT_OPEN_CLOSE | WHERE_AND_ONLY |
                        WHERE_FORCE_TABLE | WHERE_ONETABLE_ONLY, iCovCur);
        assert( pSubWInfo || pParse->nErr || pParse->db->mallocFailed );
        if( pSubWInfo ){
          WhereLoop *pSubLoop;
          explainOneScan(
              pParse, pOrTab, &pSubWInfo->a[0], iLevel, pLevel->iFrom, 0
          );
          if( (pWInfo->wctrlFlags & WHERE_DUPLICATES_OK)==0 ){
            int iSet = ((ii==pOrWc->nTerm-1)?-1:ii);
            sqlite4VdbeAddOp2(v, OP_RowKey, iCur, regKey);
            sqlite4VdbeAddOp4Int(v, OP_RowSetTest, regKeyset,

static int whereLoopAddBtree(
  WhereLoopBuilder *pBuilder, /* WHERE clause information */
  Bitmask mExtra              /* Extra prerequesites for using this table */
){
  WhereInfo *pWInfo;          /* WHERE analysis context */
  Index *pProbe;              /* An index we are evaluating */
  Index *pPk;                 /* Primary key index for table pSrc */
  tRowcnt aiRowEstPk[2];      /* The aiRowEst[] value for the sPk index */
  int aiColumnPk = -1;        /* The aColumn[] value for the sPk index */
  SrcList *pTabList;          /* The FROM clause */
  struct SrcListItem *pSrc;   /* The FROM clause btree term to add */
  WhereLoop *pNew;            /* Template WhereLoop object */
  int rc = SQLITE4_OK;        /* Return code */
  int iSortIdx = 1;           /* Index number */
  int b;                      /* A boolean value */
  WhereCost rSize;            /* number of rows in the table */