/*
** 2013年11月12日
**
** The author disclaims copyright to this source code. In place of
** a legal notice, here is a blessing:
**
** May you do good and not evil.
** May you find forgiveness for yourself and forgive others.
** May you share freely, never taking more than you give.
**
*************************************************************************
**
** This file contains structure and macro definitions for the query
** planner logic in "where.c". These definitions are broken out into
** a separate source file for easier editing.
*/
#ifndef SQLITE_WHEREINT_H
#define SQLITE_WHEREINT_H


/* Forward references
*/
typedef struct WhereClause WhereClause;
typedef struct WhereMaskSet WhereMaskSet;
typedef struct WhereOrInfo WhereOrInfo;
typedef struct WhereAndInfo WhereAndInfo;
typedef struct WhereLevel WhereLevel;
typedef struct WhereLoop WhereLoop;
typedef struct WherePath WherePath;
typedef struct WhereTerm WhereTerm;
typedef struct WhereLoopBuilder WhereLoopBuilder;
typedef struct WhereScan WhereScan;
typedef struct WhereOrCost WhereOrCost;
typedef struct WhereOrSet WhereOrSet;
typedef struct WhereMemBlock WhereMemBlock;
typedef struct WhereRightJoin WhereRightJoin;

/*
** This object is a header on a block of allocated memory that will be
** automatically freed when its WInfo object is destructed.
*/
struct WhereMemBlock {
 WhereMemBlock *pNext; /* Next block in the chain */
 u64 sz; /* Bytes of space */
};

/*
** Extra information attached to a WhereLevel that is a RIGHT JOIN.
*/
struct WhereRightJoin {
 int iMatch; /* Cursor used to determine prior matched rows */
 int regBloom; /* Bloom filter for iRJMatch */
 int regReturn; /* Return register for the interior subroutine */
 int addrSubrtn; /* Starting address for the interior subroutine */
 int endSubrtn; /* The last opcode in the interior subroutine */
};

/*
** This object contains information needed to implement a single nested
** loop in WHERE clause.
**
** Contrast this object with WhereLoop. This object describes the
** implementation of the loop. WhereLoop describes the algorithm.
** This object contains a pointer to the WhereLoop algorithm as one of
** its elements.
**
** The WhereInfo object contains a single instance of this object for
** each term in the FROM clause (which is to say, for each of the
** nested loops as implemented). The order of WhereLevel objects determines
** the loop nested order, with WhereInfo.a[0] being the outer loop and
** WhereInfo.a[WhereInfo.nLevel-1] being the inner loop.
*/
struct WhereLevel {
 int iLeftJoin; /* Memory cell used to implement LEFT OUTER JOIN */
 int iTabCur; /* The VDBE cursor used to access the table */
 int iIdxCur; /* The VDBE cursor used to access pIdx */
 int addrBrk; /* Jump here to break out of the loop */
 int addrHalt; /* Abort the query due to empty table or similar */
 int addrNxt; /* Jump here to start the next IN combination */
 int addrSkip; /* Jump here for next iteration of skip-scan */
 int addrCont; /* Jump here to continue with the next loop cycle */
 int addrFirst; /* First instruction of interior of the loop */
 int addrBody; /* Beginning of the body of this loop */
 int regBignull; /* big-null flag reg. True if a NULL-scan is needed */
 int addrBignull; /* Jump here for next part of big-null scan */
#ifndef SQLITE_LIKE_DOESNT_MATCH_BLOBS
 u32 iLikeRepCntr; /* LIKE range processing counter register (times 2) */
 int addrLikeRep; /* LIKE range processing address */
#endif
 int regFilter; /* Bloom filter */
 WhereRightJoin *pRJ; /* Extra information for RIGHT JOIN */
 u8 iFrom; /* Which entry in the FROM clause */
 u8 op, p3, p5; /* Opcode, P3 & P5 of the opcode that ends the loop */
 int p1, p2; /* Operands of the opcode used to end the loop */
 union { /* Information that depends on pWLoop->wsFlags */
 struct {
 int nIn; /* Number of entries in aInLoop[] */
 struct InLoop {
 int iCur; /* The VDBE cursor used by this IN operator */
 int addrInTop; /* Top of the IN loop */
 int iBase; /* Base register of multi-key index record */
 int nPrefix; /* Number of prior entries in the key */
 u8 eEndLoopOp; /* IN Loop terminator. OP_Next or OP_Prev */
 } *aInLoop; /* Information about each nested IN operator */
 } in; /* Used when pWLoop->wsFlags&WHERE_IN_ABLE */
 Index *pCoveringIdx; /* Possible covering index for WHERE_MULTI_OR */
 } u;
 struct WhereLoop *pWLoop; /* The selected WhereLoop object */
 Bitmask notReady; /* FROM entries not usable at this level */
#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
 int addrVisit; /* Address at which row is visited */
#endif
};

/*
** Each instance of this object represents an algorithm for evaluating one
** term of a join. Every term of the FROM clause will have at least
** one corresponding WhereLoop object (unless INDEXED BY constraints
** prevent a query solution - which is an error) and many terms of the
** FROM clause will have multiple WhereLoop objects, each describing a
** potential way of implementing that FROM-clause term, together with
** dependencies and cost estimates for using the chosen algorithm.
**
** Query planning consists of building up a collection of these WhereLoop
** objects, then computing a particular sequence of WhereLoop objects, with
** one WhereLoop object per FROM clause term, that satisfy all dependencies
** and that minimize the overall cost.
*/
struct WhereLoop {
 Bitmask prereq; /* Bitmask of other loops that must run first */
 Bitmask maskSelf; /* Bitmask identifying table iTab */
#ifdef SQLITE_DEBUG
 char cId; /* Symbolic ID of this loop for debugging use */
#endif
 u8 iTab; /* Position in FROM clause of table for this loop */
 u8 iSortIdx; /* Sorting index number. 0==None */
 LogEst rSetup; /* One-time setup cost (ex: create transient index) */
 LogEst rRun; /* Cost of running each loop */
 LogEst nOut; /* Estimated number of output rows */
 union {
 struct { /* Information for internal btree tables */
 u16 nEq; /* Number of equality constraints */
 u16 nBtm; /* Size of BTM vector */
 u16 nTop; /* Size of TOP vector */
 u16 nDistinctCol; /* Index columns used to sort for DISTINCT */
 Index *pIndex; /* Index used, or NULL */
 ExprList *pOrderBy; /* ORDER BY clause if this is really a subquery */
 } btree;
 struct { /* Information for virtual tables */
 int idxNum; /* Index number */
 u32 needFree : 1; /* True if sqlite3_free(idxStr) is needed */
 u32 bOmitOffset : 1; /* True to let virtual table handle offset */
 u32 bIdxNumHex : 1; /* Show idxNum as hex in EXPLAIN QUERY PLAN */
 i8 isOrdered; /* True if satisfies ORDER BY */
 u16 omitMask; /* Terms that may be omitted */
 char *idxStr; /* Index identifier string */
 u32 mHandleIn; /* Terms to handle as IN(...) instead of == */
 } vtab;
 } u;
 u32 wsFlags; /* WHERE_* flags describing the plan */
 u16 nLTerm; /* Number of entries in aLTerm[] */
 u16 nSkip; /* Number of NULL aLTerm[] entries */
 /**** whereLoopXfer() copies fields above ***********************/
# define WHERE_LOOP_XFER_SZ offsetof(WhereLoop,nLSlot)
 u16 nLSlot; /* Number of slots allocated for aLTerm[] */
#ifdef WHERETRACE_ENABLED
 LogEst rStarDelta; /* Cost delta due to star-schema heuristic. Not
 ** initialized unless pWInfo->bStarUsed */
#endif
 WhereTerm **aLTerm; /* WhereTerms used */
 WhereLoop *pNextLoop; /* Next WhereLoop object in the WhereClause */
 WhereTerm *aLTermSpace[3]; /* Initial aLTerm[] space */
};

/* This object holds the prerequisites and the cost of running a
** subquery on one operand of an OR operator in the WHERE clause.
** See WhereOrSet for additional information
*/
struct WhereOrCost {
 Bitmask prereq; /* Prerequisites */
 LogEst rRun; /* Cost of running this subquery */
 LogEst nOut; /* Number of outputs for this subquery */
};

/* The WhereOrSet object holds a set of possible WhereOrCosts that
** correspond to the subquery(s) of OR-clause processing. Only the
** best N_OR_COST elements are retained.
*/
#define N_OR_COST 3
struct WhereOrSet {
 u16 n; /* Number of valid a[] entries */
 WhereOrCost a[N_OR_COST]; /* Set of best costs */
};

/*
** Each instance of this object holds a sequence of WhereLoop objects
** that implement some or all of a query plan.
**
** Think of each WhereLoop object as a node in a graph with arcs
** showing dependencies and costs for travelling between nodes. (That is
** not a completely accurate description because WhereLoop costs are a
** vector, not a scalar, and because dependencies are many-to-one, not
** one-to-one as are graph nodes. But it is a useful visualization aid.)
** Then a WherePath object is a path through the graph that visits some
** or all of the WhereLoop objects once.
**
** The "solver" works by creating the N best WherePath objects of length
** 1. Then using those as a basis to compute the N best WherePath objects
** of length 2. And so forth until the length of WherePaths equals the
** number of nodes in the FROM clause. The best (lowest cost) WherePath
** at the end is the chosen query plan.
*/
struct WherePath {
 Bitmask maskLoop; /* Bitmask of all WhereLoop objects in this path */
 Bitmask revLoop; /* aLoop[]s that should be reversed for ORDER BY */
 LogEst nRow; /* Estimated number of rows generated by this path */
 LogEst rCost; /* Total cost of this path */
 LogEst rUnsort; /* Total cost of this path ignoring sorting costs */
 i8 isOrdered; /* No. of ORDER BY terms satisfied. -1 for unknown */
 WhereLoop **aLoop; /* Array of WhereLoop objects implementing this path */
};

/*
** The query generator uses an array of instances of this structure to
** help it analyze the subexpressions of the WHERE clause. Each WHERE
** clause subexpression is separated from the others by AND operators,
** usually, or sometimes subexpressions separated by OR.
**
** All WhereTerms are collected into a single WhereClause structure. 
** The following identity holds:
**
** WhereTerm.pWC->a[WhereTerm.idx] == WhereTerm
**
** When a term is of the form:
**
** X <op> <expr>
**
** where X is a column name and <op> is one of certain operators,
** then WhereTerm.leftCursor and WhereTerm.u.leftColumn record the
** cursor number and column number for X. WhereTerm.eOperator records
** the <op> using a bitmask encoding defined by WO_xxx below. The
** use of a bitmask encoding for the operator allows us to search
** quickly for terms that match any of several different operators.
**
** A WhereTerm might also be two or more subterms connected by OR:
**
** (t1.X <op> <expr>) OR (t1.Y <op> <expr>) OR ....
**
** In this second case, wtFlag has the TERM_ORINFO bit set and eOperator==WO_OR
** and the WhereTerm.u.pOrInfo field points to auxiliary information that
** is collected about the OR clause.
**
** If a term in the WHERE clause does not match either of the two previous
** categories, then eOperator==0. The WhereTerm.pExpr field is still set
** to the original subexpression content and wtFlags is set up appropriately
** but no other fields in the WhereTerm object are meaningful.
**
** When eOperator!=0, prereqRight and prereqAll record sets of cursor numbers,
** but they do so indirectly. A single WhereMaskSet structure translates
** cursor number into bits and the translated bit is stored in the prereq
** fields. The translation is used in order to maximize the number of
** bits that will fit in a Bitmask. The VDBE cursor numbers might be
** spread out over the non-negative integers. For example, the cursor
** numbers might be 3, 8, 9, 10, 20, 23, 41, and 45. The WhereMaskSet
** translates these sparse cursor numbers into consecutive integers
** beginning with 0 in order to make the best possible use of the available
** bits in the Bitmask. So, in the example above, the cursor numbers
** would be mapped into integers 0 through 7.
**
** The number of terms in a join is limited by the number of bits
** in prereqRight and prereqAll. The default is 64 bits, hence SQLite
** is only able to process joins with 64 or fewer tables.
*/
struct WhereTerm {
 Expr *pExpr; /* Pointer to the subexpression that is this term */
 WhereClause *pWC; /* The clause this term is part of */
 LogEst truthProb; /* Probability of truth for this expression */
 u16 wtFlags; /* TERM_xxx bit flags. See below */
 u16 eOperator; /* A WO_xx value describing <op> */
 u8 nChild; /* Number of children that must disable us */
 u8 eMatchOp; /* Op for vtab MATCH/LIKE/GLOB/REGEXP terms */
 int iParent; /* Disable pWC->a[iParent] when this term disabled */
 int leftCursor; /* Cursor number of X in "X <op> <expr>" */
#ifdef SQLITE_DEBUG
 int iTerm; /* Which WhereTerm is this, for debug purposes */
#endif
 union {
 struct {
 int leftColumn; /* Column number of X in "X <op> <expr>" */
 int iField; /* Field in (?,?,?) IN (SELECT...) vector */
 } x; /* Opcode other than OP_OR or OP_AND */
 WhereOrInfo *pOrInfo; /* Extra information if (eOperator & WO_OR)!=0 */
 WhereAndInfo *pAndInfo; /* Extra information if (eOperator& WO_AND)!=0 */
 } u;
 Bitmask prereqRight; /* Bitmask of tables used by pExpr->pRight */
 Bitmask prereqAll; /* Bitmask of tables referenced by pExpr */
};

/*
** Allowed values of WhereTerm.wtFlags
*/
#define TERM_DYNAMIC 0x0001 /* Need to call sqlite3ExprDelete(db, pExpr) */
#define TERM_VIRTUAL 0x0002 /* Added by the optimizer. Do not code */
#define TERM_CODED 0x0004 /* This term is already coded */
#define TERM_COPIED 0x0008 /* Has a child */
#define TERM_ORINFO 0x0010 /* Need to free the WhereTerm.u.pOrInfo object */
#define TERM_ANDINFO 0x0020 /* Need to free the WhereTerm.u.pAndInfo obj */
#define TERM_OK 0x0040 /* Used during OR-clause processing */
#define TERM_VNULL 0x0080 /* Manufactured x>NULL or x<=NULL term */
#define TERM_LIKEOPT 0x0100 /* Virtual terms from the LIKE optimization */
#define TERM_LIKECOND 0x0200 /* Conditionally this LIKE operator term */
#define TERM_LIKE 0x0400 /* The original LIKE operator */
#define TERM_IS 0x0800 /* Term.pExpr is an IS operator */
#define TERM_VARSELECT 0x1000 /* Term.pExpr contains a correlated sub-query */
#define TERM_HEURTRUTH 0x2000 /* Heuristic truthProb used */
#ifdef SQLITE_ENABLE_STAT4
# define TERM_HIGHTRUTH 0x4000 /* Term excludes few rows */
#else
# define TERM_HIGHTRUTH 0 /* Only used with STAT4 */
#endif
#define TERM_SLICE 0x8000 /* One slice of a row-value/vector comparison */

/*
** An instance of the WhereScan object is used as an iterator for locating
** terms in the WHERE clause that are useful to the query planner.
*/
struct WhereScan {
 WhereClause *pOrigWC; /* Original, innermost WhereClause */
 WhereClause *pWC; /* WhereClause currently being scanned */
 const char *zCollName; /* Required collating sequence, if not NULL */
 Expr *pIdxExpr; /* Search for this index expression */
 int k; /* Resume scanning at this->pWC->a[this->k] */
 u32 opMask; /* Acceptable operators */
 char idxaff; /* Must match this affinity, if zCollName!=NULL */
 unsigned char iEquiv; /* Current slot in aiCur[] and aiColumn[] */
 unsigned char nEquiv; /* Number of entries in aiCur[] and aiColumn[] */
 int aiCur[11]; /* Cursors in the equivalence class */
 i16 aiColumn[11]; /* Corresponding column number in the eq-class */
};

/*
** An instance of the following structure holds all information about a
** WHERE clause. Mostly this is a container for one or more WhereTerms.
**
** Explanation of pOuter: For a WHERE clause of the form
**
** a AND ((b AND c) OR (d AND e)) AND f
**
** There are separate WhereClause objects for the whole clause and for
** the subclauses "(b AND c)" and "(d AND e)". The pOuter field of the
** subclauses points to the WhereClause object for the whole clause.
*/
struct WhereClause {
 WhereInfo *pWInfo; /* WHERE clause processing context */
 WhereClause *pOuter; /* Outer conjunction */
 u8 op; /* Split operator. TK_AND or TK_OR */
 u8 hasOr; /* True if any a[].eOperator is WO_OR */
 int nTerm; /* Number of terms */
 int nSlot; /* Number of entries in a[] */
 int nBase; /* Number of terms through the last non-Virtual */
 WhereTerm *a; /* Each a[] describes a term of the WHERE clause */
#if defined(SQLITE_SMALL_STACK)
 WhereTerm aStatic[1]; /* Initial static space for a[] */
#else
 WhereTerm aStatic[8]; /* Initial static space for a[] */
#endif
};

/*
** A WhereTerm with eOperator==WO_OR has its u.pOrInfo pointer set to
** a dynamically allocated instance of the following structure.
*/
struct WhereOrInfo {
 WhereClause wc; /* Decomposition into subterms */
 Bitmask indexable; /* Bitmask of all indexable tables in the clause */
};

/*
** A WhereTerm with eOperator==WO_AND has its u.pAndInfo pointer set to
** a dynamically allocated instance of the following structure.
*/
struct WhereAndInfo {
 WhereClause wc; /* The subexpression broken out */
};

/*
** An instance of the following structure keeps track of a mapping
** between VDBE cursor numbers and bits of the bitmasks in WhereTerm.
**
** The VDBE cursor numbers are small integers contained in
** SrcItem.iCursor and Expr.iTable fields. For any given WHERE
** clause, the cursor numbers might not begin with 0 and they might
** contain gaps in the numbering sequence. But we want to make maximum
** use of the bits in our bitmasks. This structure provides a mapping
** from the sparse cursor numbers into consecutive integers beginning
** with 0.
**
** If WhereMaskSet.ix[A]==B it means that The A-th bit of a Bitmask
** corresponds VDBE cursor number B. The A-th bit of a bitmask is 1<<A.
**
** For example, if the WHERE clause expression used these VDBE
** cursors: 4, 5, 8, 29, 57, 73. Then the WhereMaskSet structure
** would map those cursor numbers into bits 0 through 5.
**
** Note that the mapping is not necessarily ordered. In the example
** above, the mapping might go like this: 4->3, 5->1, 8->2, 29->0,
** 57->5, 73->4. Or one of 719 other combinations might be used. It
** does not really matter. What is important is that sparse cursor
** numbers all get mapped into bit numbers that begin with 0 and contain
** no gaps.
*/
struct WhereMaskSet {
 int bVarSelect; /* Used by sqlite3WhereExprUsage() */
 int n; /* Number of assigned cursor values */
 int ix[BMS]; /* Cursor assigned to each bit */
};

/*
** This object is a convenience wrapper holding all information needed
** to construct WhereLoop objects for a particular query.
*/
struct WhereLoopBuilder {
 WhereInfo *pWInfo; /* Information about this WHERE */
 WhereClause *pWC; /* WHERE clause terms */
 WhereLoop *pNew; /* Template WhereLoop */
 WhereOrSet *pOrSet; /* Record best loops here, if not NULL */
#ifdef SQLITE_ENABLE_STAT4
 UnpackedRecord *pRec; /* Probe for stat4 (if required) */
 int nRecValid; /* Number of valid fields currently in pRec */
#endif
 unsigned char bldFlags1; /* First set of SQLITE_BLDF_* flags */
 unsigned char bldFlags2; /* Second set of SQLITE_BLDF_* flags */
 unsigned int iPlanLimit; /* Search limiter */
};

/* Allowed values for WhereLoopBuider.bldFlags */
#define SQLITE_BLDF1_INDEXED 0x0001 /* An index is used */
#define SQLITE_BLDF1_UNIQUE 0x0002 /* All keys of a UNIQUE index used */

#define SQLITE_BLDF2_2NDPASS 0x0004 /* Second builder pass needed */

/* The WhereLoopBuilder.iPlanLimit is used to limit the number of
** index+constraint combinations the query planner will consider for a
** particular query. If this parameter is unlimited, then certain
** pathological queries can spend excess time in the sqlite3WhereBegin()
** routine. The limit is high enough that is should not impact real-world
** queries.
**
** SQLITE_QUERY_PLANNER_LIMIT is the baseline limit. The limit is
** increased by SQLITE_QUERY_PLANNER_LIMIT_INCR before each term of the FROM
** clause is processed, so that every table in a join is guaranteed to be
** able to propose a some index+constraint combinations even if the initial
** baseline limit was exhausted by prior tables of the join.
*/
#ifndef SQLITE_QUERY_PLANNER_LIMIT
# define SQLITE_QUERY_PLANNER_LIMIT 20000
#endif
#ifndef SQLITE_QUERY_PLANNER_LIMIT_INCR
# define SQLITE_QUERY_PLANNER_LIMIT_INCR 1000
#endif

/*
** The WHERE clause processing routine has two halves. The
** first part does the start of the WHERE loop and the second
** half does the tail of the WHERE loop. An instance of
** this structure is returned by the first half and passed
** into the second half to give some continuity.
**
** An instance of this object holds the complete state of the query
** planner.
*/
struct WhereInfo {
 Parse *pParse; /* Parsing and code generating context */
 SrcList *pTabList; /* List of tables in the join */
 ExprList *pOrderBy; /* The ORDER BY clause or NULL */
 ExprList *pResultSet; /* Result set of the query */
#if WHERETRACE_ENABLED
 Expr *pWhere; /* The complete WHERE clause */
#endif
 Select *pSelect; /* The entire SELECT statement containing WHERE */
 int aiCurOnePass[2]; /* OP_OpenWrite cursors for the ONEPASS opt */
 int iContinue; /* Jump here to continue with next record */
 int iBreak; /* Jump here to break out of the loop */
 int savedNQueryLoop; /* pParse->nQueryLoop outside the WHERE loop */
 u16 wctrlFlags; /* Flags originally passed to sqlite3WhereBegin() */
 LogEst iLimit; /* LIMIT if wctrlFlags has WHERE_USE_LIMIT */
 u8 nLevel; /* Number of nested loop */
 i8 nOBSat; /* Number of ORDER BY terms satisfied by indices */
 u8 eOnePass; /* ONEPASS_OFF, or _SINGLE, or _MULTI */
 u8 eDistinct; /* One of the WHERE_DISTINCT_* values */
 unsigned bDeferredSeek :1; /* Uses OP_DeferredSeek */
 unsigned untestedTerms :1; /* Not all WHERE terms resolved by outer loop */
 unsigned bOrderedInnerLoop:1;/* True if only the inner-most loop is ordered */
 unsigned sorted :1; /* True if really sorted (not just grouped) */
 unsigned bStarDone :1; /* True if check for star-query is complete */
 unsigned bStarUsed :1; /* True if star-query heuristic is used */
 LogEst nRowOut; /* Estimated number of output rows */
#ifdef WHERETRACE_ENABLED
 LogEst rTotalCost; /* Total cost of the solution */
#endif
 int iTop; /* The very beginning of the WHERE loop */
 int iEndWhere; /* End of the WHERE clause itself */
 WhereLoop *pLoops; /* List of all WhereLoop objects */
 WhereMemBlock *pMemToFree;/* Memory to free when this object destroyed */
 Bitmask revMask; /* Mask of ORDER BY terms that need reversing */
 WhereClause sWC; /* Decomposition of the WHERE clause */
 WhereMaskSet sMaskSet; /* Map cursor numbers to bitmasks */
 WhereLevel a[FLEXARRAY]; /* Information about each nest loop in WHERE */
};

/*
** The size (in bytes) of a WhereInfo object that holds N WhereLevels.
*/
#define SZ_WHEREINFO(N) ROUND8(offsetof(WhereInfo,a)+(N)*sizeof(WhereLevel))

/*
** Private interfaces - callable only by other where.c routines.
**
** where.c:
*/
Bitmask sqlite3WhereGetMask(WhereMaskSet*,int);
#ifdef WHERETRACE_ENABLED
void sqlite3WhereClausePrint(WhereClause *pWC);
void sqlite3WhereTermPrint(WhereTerm *pTerm, int iTerm);
void sqlite3WhereLoopPrint(const WhereLoop *p, const WhereClause *pWC);
#endif
WhereTerm *sqlite3WhereFindTerm(
 WhereClause *pWC, /* The WHERE clause to be searched */
 int iCur, /* Cursor number of LHS */
 int iColumn, /* Column number of LHS */
 Bitmask notReady, /* RHS must not overlap with this mask */
 u32 op, /* Mask of WO_xx values describing operator */
 Index *pIdx /* Must be compatible with this index, if not NULL */
);
void *sqlite3WhereMalloc(WhereInfo *pWInfo, u64 nByte);
void *sqlite3WhereRealloc(WhereInfo *pWInfo, void *pOld, u64 nByte);

/* wherecode.c: */
#ifndef SQLITE_OMIT_EXPLAIN
int sqlite3WhereExplainOneScan(
 Parse *pParse, /* Parse context */
 SrcList *pTabList, /* Table list this loop refers to */
 WhereLevel *pLevel, /* Scan to write OP_Explain opcode for */
 u16 wctrlFlags /* Flags passed to sqlite3WhereBegin() */
);
int sqlite3WhereExplainBloomFilter(
 const Parse *pParse, /* Parse context */
 const WhereInfo *pWInfo, /* WHERE clause */
 const WhereLevel *pLevel /* Bloom filter on this level */
);
void sqlite3WhereAddExplainText(
 Parse *pParse, /* Parse context */
 int addr, 
 SrcList *pTabList, /* Table list this loop refers to */
 WhereLevel *pLevel, /* Scan to write OP_Explain opcode for */
 u16 wctrlFlags /* Flags passed to sqlite3WhereBegin() */
);
#else
# define sqlite3WhereExplainOneScan(u,v,w,x) 0
# define sqlite3WhereExplainBloomFilter(u,v,w) 0
# define sqlite3WhereAddExplainText(u,v,w,x,y)
#endif /* SQLITE_OMIT_EXPLAIN */
#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
void sqlite3WhereAddScanStatus(
 Vdbe *v, /* Vdbe to add scanstatus entry to */
 SrcList *pSrclist, /* FROM clause pLvl reads data from */
 WhereLevel *pLvl, /* Level to add scanstatus() entry for */
 int addrExplain /* Address of OP_Explain (or 0) */
);
#else
# define sqlite3WhereAddScanStatus(a, b, c, d) ((void)d)
#endif
Bitmask sqlite3WhereCodeOneLoopStart(
 Parse *pParse, /* Parsing context */
 Vdbe *v, /* Prepared statement under construction */
 WhereInfo *pWInfo, /* Complete information about the WHERE clause */
 int iLevel, /* Which level of pWInfo->a[] should be coded */
 WhereLevel *pLevel, /* The current level pointer */
 Bitmask notReady /* Which tables are currently available */
);
SQLITE_NOINLINE void sqlite3WhereRightJoinLoop(
 WhereInfo *pWInfo,
 int iLevel,
 WhereLevel *pLevel
);

/* whereexpr.c: */
void sqlite3WhereClauseInit(WhereClause*,WhereInfo*);
void sqlite3WhereClauseClear(WhereClause*);
void sqlite3WhereSplit(WhereClause*,Expr*,u8);
void sqlite3WhereAddLimit(WhereClause*, Select*);
Bitmask sqlite3WhereExprUsage(WhereMaskSet*, Expr*);
Bitmask sqlite3WhereExprUsageNN(WhereMaskSet*, Expr*);
Bitmask sqlite3WhereExprListUsage(WhereMaskSet*, ExprList*);
void sqlite3WhereExprAnalyze(SrcList*, WhereClause*);
void sqlite3WhereTabFuncArgs(Parse*, SrcItem*, WhereClause*);





/*
** Bitmasks for the operators on WhereTerm objects. These are all
** operators that are of interest to the query planner. An
** OR-ed combination of these values can be used when searching for
** particular WhereTerms within a WhereClause.
**
** Value constraints:
** WO_EQ == SQLITE_INDEX_CONSTRAINT_EQ
** WO_LT == SQLITE_INDEX_CONSTRAINT_LT
** WO_LE == SQLITE_INDEX_CONSTRAINT_LE
** WO_GT == SQLITE_INDEX_CONSTRAINT_GT
** WO_GE == SQLITE_INDEX_CONSTRAINT_GE
*/
#define WO_IN 0x0001
#define WO_EQ 0x0002
#define WO_LT (WO_EQ<<(TK_LT-TK_EQ))
#define WO_LE (WO_EQ<<(TK_LE-TK_EQ))
#define WO_GT (WO_EQ<<(TK_GT-TK_EQ))
#define WO_GE (WO_EQ<<(TK_GE-TK_EQ))
#define WO_AUX 0x0040 /* Op useful to virtual tables only */
#define WO_IS 0x0080
#define WO_ISNULL 0x0100
#define WO_OR 0x0200 /* Two or more OR-connected terms */
#define WO_AND 0x0400 /* Two or more AND-connected terms */
#define WO_EQUIV 0x0800 /* Of the form A==B, both columns */
#define WO_NOOP 0x1000 /* This term does not restrict search space */
#define WO_ROWVAL 0x2000 /* A row-value term */

#define WO_ALL 0x3fff /* Mask of all possible WO_* values */
#define WO_SINGLE 0x01ff /* Mask of all non-compound WO_* values */

/*
** These are definitions of bits in the WhereLoop.wsFlags field.
** The particular combination of bits in each WhereLoop help to
** determine the algorithm that WhereLoop represents.
*/
#define WHERE_COLUMN_EQ 0x00000001 /* x=EXPR */
#define WHERE_COLUMN_RANGE 0x00000002 /* x<EXPR and/or x>EXPR */
#define WHERE_COLUMN_IN 0x00000004 /* x IN (...) */
#define WHERE_COLUMN_NULL 0x00000008 /* x IS NULL */
#define WHERE_CONSTRAINT 0x0000000f /* Any of the WHERE_COLUMN_xxx values */
#define WHERE_TOP_LIMIT 0x00000010 /* x<EXPR or x<=EXPR constraint */
#define WHERE_BTM_LIMIT 0x00000020 /* x>EXPR or x>=EXPR constraint */
#define WHERE_BOTH_LIMIT 0x00000030 /* Both x>EXPR and x<EXPR */
#define WHERE_IDX_ONLY 0x00000040 /* Use index only - omit table */
#define WHERE_IPK 0x00000100 /* x is the INTEGER PRIMARY KEY */
#define WHERE_INDEXED 0x00000200 /* WhereLoop.u.btree.pIndex is valid */
#define WHERE_VIRTUALTABLE 0x00000400 /* WhereLoop.u.vtab is valid */
#define WHERE_IN_ABLE 0x00000800 /* Able to support an IN operator */
#define WHERE_ONEROW 0x00001000 /* Selects no more than one row */
#define WHERE_MULTI_OR 0x00002000 /* OR using multiple indices */
#define WHERE_AUTO_INDEX 0x00004000 /* Uses an ephemeral index */
#define WHERE_SKIPSCAN 0x00008000 /* Uses the skip-scan algorithm */
#define WHERE_UNQ_WANTED 0x00010000 /* WHERE_ONEROW would have been helpful*/
#define WHERE_PARTIALIDX 0x00020000 /* The automatic index is partial */
#define WHERE_IN_EARLYOUT 0x00040000 /* Perhaps quit IN loops early */
#define WHERE_BIGNULL_SORT 0x00080000 /* Column nEq of index is BIGNULL */
#define WHERE_IN_SEEKSCAN 0x00100000 /* Seek-scan optimization for IN */
#define WHERE_TRANSCONS 0x00200000 /* Uses a transitive constraint */
#define WHERE_BLOOMFILTER 0x00400000 /* Consider using a Bloom-filter */
#define WHERE_SELFCULL 0x00800000 /* nOut reduced by extra WHERE terms */
#define WHERE_OMIT_OFFSET 0x01000000 /* Set offset counter to zero */
#define WHERE_COROUTINE 0x02000000 /* Implemented by co-routine.
 ** NB: False-negatives are possible */
#define WHERE_EXPRIDX 0x04000000 /* Uses an index-on-expressions */

#endif /* !defined(SQLITE_WHEREINT_H) */