/*

 ** 2001 September 15

 **

 ** The author disclaims copyright to this source code.  In place of

 ** a legal notice, here is a blessing:

 **

 **    May you do good and not evil.

 **    May you find forgiveness for yourself and forgive others.

 **    May you share freely, never taking more than you give.

 **

 *************************************************************************

 ** Internal interface definitions for SQLite.

 **

 ** @(#) $Id: sqliteInt.h,v 1.784 2008/10/13 15:35:09 drh Exp $

 */

 #ifndef _SQLITEINT_H_

 #define _SQLITEINT_H_

 /*

 ** Include the configuration header output by 'configure' if we're using the

 ** autoconf-based build

 */

 #ifdef _HAVE_SQLITE_CONFIG_H

 #include "config.h"

 #endif

 #include "sqliteLimit.h"

 /* Disable nuisance warnings on Borland compilers */

 #if defined(__BORLANDC__)

 #pragma warn -rch /* unreachable code */

 #pragma warn -ccc /* Condition is always true or false */

 #pragma warn -aus /* Assigned value is never used */

 #pragma warn -csu /* Comparing signed and unsigned */

 #pragma warn -spa /* Suspicous pointer arithmetic */

 #endif

 /* Needed for various definitions... */

 #ifndef _GNU_SOURCE

 # define _GNU_SOURCE

 #endif

 /*

 ** Include standard header files as necessary

 */

 #ifdef HAVE_STDINT_H

 #include <stdint.h>

 #endif

 #ifdef HAVE_INTTYPES_H

 #include <inttypes.h>

 #endif

 /*

 ** A macro used to aid in coverage testing.  When doing coverage

 ** testing, the condition inside the argument must be evaluated 

 ** both true and false in order to get full branch coverage.

 ** This macro can be inserted to ensure adequate test coverage

 ** in places where simple condition/decision coverage is inadequate.

 */

 #ifdef SQLITE_COVERAGE_TEST

   void sqlite3Coverage(int);

 # define testcase(X)  if( X ){ sqlite3Coverage(__LINE__); }

 #else

 # define testcase(X)

 #endif

 /*

 ** The ALWAYS and NEVER macros surround boolean expressions which 

 ** are intended to always be true or false, respectively.  Such

 ** expressions could be omitted from the code completely.  But they

 ** are included in a few cases in order to enhance the resilience

 ** of SQLite to unexpected behavior - to make the code "self-healing"

 ** or "ductile" rather than being "brittle" and crashing at the first

 ** hint of unplanned behavior.

 **

 ** When doing coverage testing ALWAYS and NEVER are hard-coded to

 ** be true and false so that the unreachable code then specify will

 ** not be counted as untested code.

 */

 #ifdef SQLITE_COVERAGE_TEST

 # define ALWAYS(X)      (1)

 # define NEVER(X)       (0)

 #else

 # define ALWAYS(X)      (X)

 # define NEVER(X)       (X)

 #endif

 /*

 ** The macro unlikely() is a hint that surrounds a boolean

 ** expression that is usually false.  Macro likely() surrounds

 ** a boolean expression that is usually true.  GCC is able to

 ** use these hints to generate better code, sometimes.

 */

 #if defined(__GNUC__) && 0

 # define likely(X)    __builtin_expect((X),1)

 # define unlikely(X)  __builtin_expect((X),0)

 #else

 # define likely(X)    !!(X)

 # define unlikely(X)  !!(X)

 #endif

 /*

  * This macro is used to "hide" some ugliness in casting an int

  * value to a ptr value under the MSVC 64-bit compiler.   Casting

  * non 64-bit values to ptr types results in a "hard" error with 

  * the MSVC 64-bit compiler which this attempts to avoid.  

  *

  * A simple compiler pragma or casting sequence could not be found

  * to correct this in all situations, so this macro was introduced.

  *

  * It could be argued that the intptr_t type could be used in this

  * case, but that type is not available on all compilers, or 

  * requires the #include of specific headers which differs between

  * platforms.

  */

 #define SQLITE_INT_TO_PTR(X)   ((void*)&((char*)0)[X])

 #define SQLITE_PTR_TO_INT(X)   ((int)(((char*)X)-(char*)0))

 /*

 ** These #defines should enable >2GB file support on Posix if the

 ** underlying operating system supports it.  If the OS lacks

 ** large file support, or if the OS is windows, these should be no-ops.

 **

 ** Ticket #2739:  The _LARGEFILE_SOURCE macro must appear before any

 ** system #includes.  Hence, this block of code must be the very first

 ** code in all source files.

 **

 ** Large file support can be disabled using the -DSQLITE_DISABLE_LFS switch

 ** on the compiler command line.  This is necessary if you are compiling

 ** on a recent machine (ex: RedHat 7.2) but you want your code to work

 ** on an older machine (ex: RedHat 6.0).  If you compile on RedHat 7.2

 ** without this option, LFS is enable.  But LFS does not exist in the kernel

 ** in RedHat 6.0, so the code won't work.  Hence, for maximum binary

 ** portability you should omit LFS.

 **

 ** Similar is true for MacOS.  LFS is only supported on MacOS 9 and later.

 */

 #ifndef SQLITE_DISABLE_LFS

 # define _LARGE_FILE       1

 # ifndef _FILE_OFFSET_BITS

 #   define _FILE_OFFSET_BITS 64

 # endif

 # define _LARGEFILE_SOURCE 1

 #endif

 /*

 ** The SQLITE_THREADSAFE macro must be defined as either 0 or 1.

 ** Older versions of SQLite used an optional THREADSAFE macro.

 ** We support that for legacy

 */

 #if !defined(SQLITE_THREADSAFE)

 #if defined(THREADSAFE)

 # define SQLITE_THREADSAFE THREADSAFE

 #else

 # define SQLITE_THREADSAFE 1

 #endif

 #endif

 /*

 ** The SQLITE_DEFAULT_MEMSTATUS macro must be defined as either 0 or 1.

 ** It determines whether or not the features related to 

 ** SQLITE_CONFIG_MEMSTATUS are availabe by default or not. This value can

 ** be overridden at runtime using the sqlite3_config() API.

 */

 #if !defined(SQLITE_DEFAULT_MEMSTATUS)

 # define SQLITE_DEFAULT_MEMSTATUS 1

 #endif

 /*

 ** Exactly one of the following macros must be defined in order to

 ** specify which memory allocation subsystem to use.

 **

 **     SQLITE_SYSTEM_MALLOC          // Use normal system malloc()

 **     SQLITE_MEMDEBUG               // Debugging version of system malloc()

 **     SQLITE_MEMORY_SIZE            // internal allocator #1

 **     SQLITE_MMAP_HEAP_SIZE         // internal mmap() allocator

 **     SQLITE_POW2_MEMORY_SIZE       // internal power-of-two allocator

 **

 ** If none of the above are defined, then set SQLITE_SYSTEM_MALLOC as

 ** the default.

 */

 #if defined(SQLITE_SYSTEM_MALLOC)+defined(SQLITE_MEMDEBUG)+\

     defined(SQLITE_MEMORY_SIZE)+defined(SQLITE_MMAP_HEAP_SIZE)+\

     defined(SQLITE_POW2_MEMORY_SIZE)>1

 # error "At most one of the following compile-time configuration options\

  is allows: SQLITE_SYSTEM_MALLOC, SQLITE_MEMDEBUG, SQLITE_MEMORY_SIZE,\

  SQLITE_MMAP_HEAP_SIZE, SQLITE_POW2_MEMORY_SIZE"

 #endif

 #if defined(SQLITE_SYSTEM_MALLOC)+defined(SQLITE_MEMDEBUG)+\

     defined(SQLITE_MEMORY_SIZE)+defined(SQLITE_MMAP_HEAP_SIZE)+\

     defined(SQLITE_POW2_MEMORY_SIZE)==0

 # define SQLITE_SYSTEM_MALLOC 1

 #endif

 /*

 ** If SQLITE_MALLOC_SOFT_LIMIT is defined, then try to keep the

 ** sizes of memory allocations below this value where possible.

 */

 #if defined(SQLITE_POW2_MEMORY_SIZE) && !defined(SQLITE_MALLOC_SOFT_LIMIT)

 # define SQLITE_MALLOC_SOFT_LIMIT 1024

 #endif

 /*

 ** We need to define _XOPEN_SOURCE as follows in order to enable

 ** recursive mutexes on most unix systems.  But Mac OS X is different.

 ** The _XOPEN_SOURCE define causes problems for Mac OS X we are told,

 ** so it is omitted there.  See ticket #2673.

 **

 ** Later we learn that _XOPEN_SOURCE is poorly or incorrectly

 ** implemented on some systems.  So we avoid defining it at all

 ** if it is already defined or if it is unneeded because we are

 ** not doing a threadsafe build.  Ticket #2681.

 **

 ** See also ticket #2741.

 */

 #if !defined(_XOPEN_SOURCE) && !defined(__DARWIN__) && !defined(__APPLE__) && SQLITE_THREADSAFE

 #  define _XOPEN_SOURCE 500  /* Needed to enable pthread recursive mutexes */

 #endif

 /*

 ** The TCL headers are only needed when compiling the TCL bindings.

 */

 #if defined(SQLITE_TCL) || defined(TCLSH)

 # include <tcl.h>

 #endif

 /*

 ** Many people are failing to set -DNDEBUG=1 when compiling SQLite.

 ** Setting NDEBUG makes the code smaller and run faster.  So the following

 ** lines are added to automatically set NDEBUG unless the -DSQLITE_DEBUG=1

 ** option is set.  Thus NDEBUG becomes an opt-in rather than an opt-out

 ** feature.

 */

 #if !defined(NDEBUG) && !defined(SQLITE_DEBUG) 

 # define NDEBUG 1

 #endif

 #include "sqlite3.h"

 #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 SQLITE_OMIT_FLOATING_POINT

 # define double sqlite_int64

 # define LONGDOUBLE_TYPE sqlite_int64

 # ifndef SQLITE_BIG_DBL

 #   define SQLITE_BIG_DBL (0x7fffffffffffffff)

 # endif

 # define SQLITE_OMIT_DATETIME_FUNCS 1

 # define SQLITE_OMIT_TRACE 1

 # undef SQLITE_MIXED_ENDIAN_64BIT_FLOAT

 #endif

 #ifndef SQLITE_BIG_DBL

 # define SQLITE_BIG_DBL (1e99)

 #endif

 /*

 ** OMIT_TEMPDB is set to 1 if SQLITE_OMIT_TEMPDB is defined, or 0

 ** afterward. Having this macro allows us to cause the C compiler 

 ** to omit code used by TEMP tables without messy #ifndef statements.

 */

 #ifdef SQLITE_OMIT_TEMPDB

 #define OMIT_TEMPDB 1

 #else

 #define OMIT_TEMPDB 0

 #endif

 /*

 ** If the following macro is set to 1, then NULL values are considered

 ** distinct when determining whether or not two entries are the same

 ** in a UNIQUE index.  This is the way PostgreSQL, Oracle, DB2, MySQL,

 ** OCELOT, and Firebird all work.  The SQL92 spec explicitly says this

 ** is the way things are suppose to work.

 **

 ** If the following macro is set to 0, the NULLs are indistinct for

 ** a UNIQUE index.  In this mode, you can only have a single NULL entry

 ** for a column declared UNIQUE.  This is the way Informix and SQL Server

 ** work.

 */

 #define NULL_DISTINCT_FOR_UNIQUE 1

 /*

 ** The "file format" number is an integer that is incremented whenever

 ** the VDBE-level file format changes.  The following macros define the

 ** the default file format for new databases and the maximum file format

 ** that the library can read.

 */

 #define SQLITE_MAX_FILE_FORMAT 4

 #ifndef SQLITE_DEFAULT_FILE_FORMAT

 # define SQLITE_DEFAULT_FILE_FORMAT 1

 #endif

 /*

 ** Provide a default value for SQLITE_TEMP_STORE in case it is not specified

 ** on the command-line

 */

 #ifndef SQLITE_TEMP_STORE

 # define SQLITE_TEMP_STORE 1

 #endif

 /*

 ** GCC does not define the offsetof() macro so we'll have to do it

 ** ourselves.

 */

 #ifndef offsetof

 #define offsetof(STRUCTURE,FIELD) ((int)((char*)&((STRUCTURE*)0)->FIELD))

 #endif

 /*

 ** Check to see if this machine uses EBCDIC.  (Yes, believe it or

 ** not, there are still machines out there that use EBCDIC.)

 */

 #if 'A' == '\301'

 # define SQLITE_EBCDIC 1

 #else

 # define SQLITE_ASCII 1

 #endif

 /*

 ** Integers of known sizes.  These typedefs might change for architectures

 ** where the sizes very.  Preprocessor macros are available so that the

 ** types can be conveniently redefined at compile-type.  Like this:

 **

 **         cc '-DUINTPTR_TYPE=long long int' ...

 */

 #ifndef UINT32_TYPE

 # ifdef HAVE_UINT32_T

 #  define UINT32_TYPE uint32_t

 # else

 #  define UINT32_TYPE unsigned int

 # endif

 #endif

 #ifndef UINT16_TYPE

 # ifdef HAVE_UINT16_T

 #  define UINT16_TYPE uint16_t

 # else

 #  define UINT16_TYPE unsigned short int

 # endif

 #endif

 #ifndef INT16_TYPE

 # ifdef HAVE_INT16_T

 #  define INT16_TYPE int16_t

 # else

 #  define INT16_TYPE short int

 # endif

 #endif

 #ifndef UINT8_TYPE

 # ifdef HAVE_UINT8_T

 #  define UINT8_TYPE uint8_t

 # else

 #  define UINT8_TYPE unsigned char

 # endif

 #endif

 #ifndef INT8_TYPE

 # ifdef HAVE_INT8_T

 #  define INT8_TYPE int8_t

 # else

 #  define INT8_TYPE signed char

 # endif

 #endif

 #ifndef LONGDOUBLE_TYPE

 # define LONGDOUBLE_TYPE long double

 #endif

 typedef sqlite_int64 i64;          /* 8-byte signed integer */

 typedef sqlite_uint64 u64;         /* 8-byte unsigned integer */

 typedef UINT32_TYPE u32;           /* 4-byte unsigned integer */

 typedef UINT16_TYPE u16;           /* 2-byte unsigned integer */

 typedef INT16_TYPE i16;            /* 2-byte signed integer */

 typedef UINT8_TYPE u8;             /* 1-byte unsigned integer */

 typedef INT8_TYPE i8;              /* 1-byte signed integer */

 /*

 ** Macros to determine whether the machine is big or little endian,

 ** evaluated at runtime.

 */

 #ifdef SQLITE_AMALGAMATION

 const int sqlite3one;

 #else

 extern const int sqlite3one;

 #endif

 #if defined(i386) || defined(__i386__) || defined(_M_IX86)\

                              || defined(__x86_64) || defined(__x86_64__)

 # define SQLITE_BIGENDIAN    0

 # define SQLITE_LITTLEENDIAN 1

 # define SQLITE_UTF16NATIVE  SQLITE_UTF16LE

 #else

 # define SQLITE_BIGENDIAN    (*(char *)(&sqlite3one)==0)

 # define SQLITE_LITTLEENDIAN (*(char *)(&sqlite3one)==1)

 # define SQLITE_UTF16NATIVE (SQLITE_BIGENDIAN?SQLITE_UTF16BE:SQLITE_UTF16LE)

 #endif

 /*

 ** Constants for the largest and smallest possible 64-bit signed integers.

 ** These macros are designed to work correctly on both 32-bit and 64-bit

 ** compilers.

 */

 #define LARGEST_INT64  (0xffffffff|(((i64)0x7fffffff)<<32))

 #define SMALLEST_INT64 (((i64)-1) - LARGEST_INT64)

 /*

 ** An instance of the following structure is used to store the busy-handler

 ** callback for a given sqlite handle. 

 **

 ** The sqlite.busyHandler member of the sqlite struct contains the busy

 ** callback for the database handle. Each pager opened via the sqlite

 ** handle is passed a pointer to sqlite.busyHandler. The busy-handler

 ** callback is currently invoked only from within pager.c.

 */

 typedef struct BusyHandler BusyHandler;

 struct BusyHandler {

   int (*xFunc)(void *,int);  /* The busy callback */

   void *pArg;                /* First arg to busy callback */

   int nBusy;                 /* Incremented with each busy call */

 };

 /*

 ** Name of the master database table.  The master database table

 ** is a special table that holds the names and attributes of all

 ** user tables and indices.

 */

 #define MASTER_NAME       "sqlite_master"

 #define TEMP_MASTER_NAME  "sqlite_temp_master"

 /*

 ** The root-page of the master database table.

 */

 #define MASTER_ROOT       1

 /*

 ** The name of the schema table.

 */

 #define SCHEMA_TABLE(x)  ((!OMIT_TEMPDB)&&(x==1)?TEMP_MASTER_NAME:MASTER_NAME)

 /*

 ** A convenience macro that returns the number of elements in

 ** an array.

 */

 #define ArraySize(X)    (sizeof(X)/sizeof(X[0]))

 /*

 ** The following value as a destructor means to use sqlite3DbFree().

 ** This is an internal extension to SQLITE_STATIC and SQLITE_TRANSIENT.

 */

 #define SQLITE_DYNAMIC   ((sqlite3_destructor_type)sqlite3DbFree)

 /*

 ** When SQLITE_OMIT_WSD is defined, it means that the target platform does

 ** not support Writable Static Data (WSD) such as global and static variables.

 ** All variables must either be on the stack or dynamically allocated from

 ** the heap.  When WSD is unsupported, the variable declarations scattered

 ** throughout the SQLite code must become constants instead.  The SQLITE_WSD

 ** macro is used for this purpose.  And instead of referencing the variable

 ** directly, we use its constant as a key to lookup the run-time allocated

 ** buffer that holds real variable.  The constant is also the initializer

 ** for the run-time allocated buffer.

 **

 ** In the usually case where WSD is supported, the SQLITE_WSD and GLOBAL

 ** macros become no-ops and have zero performance impact.

 */

 #ifdef SQLITE_OMIT_WSD

   #define SQLITE_WSD const

   #define GLOBAL(t,v) (*(t*)sqlite3_wsd_find((void*)&(v), sizeof(v)))

   #define sqlite3GlobalConfig GLOBAL(struct Sqlite3Config, sqlite3Config)

   int sqlite3_wsd_init(int N, int J);

   void *sqlite3_wsd_find(void *K, int L);

 #else

   #define SQLITE_WSD 

   #define GLOBAL(t,v) v

   #define sqlite3GlobalConfig sqlite3Config

 #endif

 /*

 ** Forward references to structures

 */

 typedef struct AggInfo AggInfo;

 typedef struct AuthContext AuthContext;

 typedef struct Bitvec Bitvec;

 typedef struct CollSeq CollSeq;

 typedef struct Column Column;

 typedef struct Db Db;

 typedef struct Schema Schema;

 typedef struct Expr Expr;

 typedef struct ExprList ExprList;

 typedef struct FKey FKey;

 typedef struct FuncDef FuncDef;

 typedef struct FuncDefHash FuncDefHash;

 typedef struct IdList IdList;

 typedef struct Index Index;

 typedef struct KeyClass KeyClass;

 typedef struct KeyInfo KeyInfo;

 typedef struct Lookaside Lookaside;

 typedef struct LookasideSlot LookasideSlot;

 typedef struct Module Module;

 typedef struct NameContext NameContext;

 typedef struct Parse Parse;

 typedef struct Select Select;

 typedef struct SrcList SrcList;

 typedef struct StrAccum StrAccum;

 typedef struct Table Table;

 typedef struct TableLock TableLock;

 typedef struct Token Token;

 typedef struct TriggerStack TriggerStack;

 typedef struct TriggerStep TriggerStep;

 typedef struct Trigger Trigger;

 typedef struct UnpackedRecord UnpackedRecord;

 typedef struct Walker Walker;

 typedef struct WhereInfo WhereInfo;

 typedef struct WhereLevel WhereLevel;

 /*

 ** Defer sourcing vdbe.h and btree.h until after the "u8" and 

 ** "BusyHandler" typedefs. vdbe.h also requires a few of the opaque

 ** pointer types (i.e. FuncDef) defined above.

 */

 #include "btree.h"

 #include "vdbe.h"

 #include "pager.h"

 #include "pcache.h"

 #include "os.h"

 #include "mutex.h"

 /*

 ** Each database file to be accessed by the system is an instance

 ** of the following structure.  There are normally two of these structures

 ** in the sqlite.aDb[] array.  aDb[0] is the main database file and

 ** aDb[1] is the database file used to hold temporary tables.  Additional

 ** databases may be attached.

 */

 struct Db {

   char *zName;         /* Name of this database */

   Btree *pBt;          /* The B*Tree structure for this database file */

   u8 inTrans;          /* 0: not writable.  1: Transaction.  2: Checkpoint */

   u8 safety_level;     /* How aggressive at synching data to disk */

   void *pAux;               /* Auxiliary data.  Usually NULL */

   void (*xFreeAux)(void*);  /* Routine to free pAux */

   Schema *pSchema;     /* Pointer to database schema (possibly shared) */

 };

 /*

 ** An instance of the following structure stores a database schema.

 **

 ** If there are no virtual tables configured in this schema, the

 ** Schema.db variable is set to NULL. After the first virtual table

 ** has been added, it is set to point to the database connection 

 ** used to create the connection. Once a virtual table has been

 ** added to the Schema structure and the Schema.db variable populated, 

 ** only that database connection may use the Schema to prepare 

 ** statements.

 */

 struct Schema {

   int schema_cookie;   /* Database schema version number for this file */

   Hash tblHash;        /* All tables indexed by name */

   Hash idxHash;        /* All (named) indices indexed by name */

   Hash trigHash;       /* All triggers indexed by name */

   Hash aFKey;          /* Foreign keys indexed by to-table */

   Table *pSeqTab;      /* The sqlite_sequence table used by AUTOINCREMENT */

   u8 file_format;      /* Schema format version for this file */

   u8 enc;              /* Text encoding used by this database */

   u16 flags;           /* Flags associated with this schema */

   int cache_size;      /* Number of pages to use in the cache */

 #ifndef SQLITE_OMIT_VIRTUALTABLE

   sqlite3 *db;         /* "Owner" connection. See comment above */

 #endif

 };

 /*

 ** These macros can be used to test, set, or clear bits in the 

 ** Db.flags field.

 */

 #define DbHasProperty(D,I,P)     (((D)->aDb[I].pSchema->flags&(P))==(P))

 #define DbHasAnyProperty(D,I,P)  (((D)->aDb[I].pSchema->flags&(P))!=0)

 #define DbSetProperty(D,I,P)     (D)->aDb[I].pSchema->flags|=(P)

 #define DbClearProperty(D,I,P)   (D)->aDb[I].pSchema->flags&=~(P)

 /*

 ** Allowed values for the DB.flags field.

 **

 ** The DB_SchemaLoaded flag is set after the database schema has been

 ** read into internal hash tables.

 **

 ** DB_UnresetViews means that one or more views have column names that

 ** have been filled out.  If the schema changes, these column names might

 ** changes and so the view will need to be reset.

 */

 #define DB_SchemaLoaded    0x0001  /* The schema has been loaded */

 #define DB_UnresetViews    0x0002  /* Some views have defined column names */

 #define DB_Empty           0x0004  /* The file is empty (length 0 bytes) */

 /*

 ** The number of different kinds of things that can be limited

 ** using the sqlite3_limit() interface.

 */

 #define SQLITE_N_LIMIT (SQLITE_LIMIT_VARIABLE_NUMBER+1)

 /*

 ** Lookaside malloc is a set of fixed-size buffers that can be used

 ** to satisify small transient memory allocation requests for objects

 ** associated with a particular database connection.  The use of

 ** lookaside malloc provides a significant performance enhancement

 ** (approx 10%) by avoiding numerous malloc/free requests while parsing

 ** SQL statements.

 **

 ** The Lookaside structure holds configuration information about the

 ** lookaside malloc subsystem.  Each available memory allocation in

 ** the lookaside subsystem is stored on a linked list of LookasideSlot

 ** objects.

 */

 struct Lookaside {

   u16 sz;                 /* Size of each buffer in bytes */

   u8 bEnabled;            /* True if use lookaside.  False to ignore it */

   u8 bMalloced;           /* True if pStart obtained from sqlite3_malloc() */

   int nOut;               /* Number of buffers currently checked out */

   int mxOut;              /* Highwater mark for nOut */

   LookasideSlot *pFree;   /* List of available buffers */

   void *pStart;           /* First byte of available memory space */

   void *pEnd;             /* First byte past end of available space */

 };

 struct LookasideSlot {

   LookasideSlot *pNext;    /* Next buffer in the list of free buffers */

 };

 /*

 ** A hash table for function definitions.

 **

 ** Hash each FuncDef structure into one of the FuncDefHash.a[] slots.

 ** Collisions are on the FuncDef.pHash chain.

 */

 struct FuncDefHash {

   FuncDef *a[23];       /* Hash table for functions */

 };

 /*

 ** Each database is an instance of the following structure.

 **

 ** The sqlite.lastRowid records the last insert rowid generated by an

 ** insert statement.  Inserts on views do not affect its value.  Each

 ** trigger has its own context, so that lastRowid can be updated inside

 ** triggers as usual.  The previous value will be restored once the trigger

 ** exits.  Upon entering a before or instead of trigger, lastRowid is no

 ** longer (since after version 2.8.12) reset to -1.

 **

 ** The sqlite.nChange does not count changes within triggers and keeps no

 ** context.  It is reset at start of sqlite3_exec.

 ** The sqlite.lsChange represents the number of changes made by the last

 ** insert, update, or delete statement.  It remains constant throughout the

 ** length of a statement and is then updated by OP_SetCounts.  It keeps a

 ** context stack just like lastRowid so that the count of changes

 ** within a trigger is not seen outside the trigger.  Changes to views do not

 ** affect the value of lsChange.

 ** The sqlite.csChange keeps track of the number of current changes (since

 ** the last statement) and is used to update sqlite_lsChange.

 **

 ** The member variables sqlite.errCode, sqlite.zErrMsg and sqlite.zErrMsg16

 ** store the most recent error code and, if applicable, string. The

 ** internal function sqlite3Error() is used to set these variables

 ** consistently.

 */

 struct sqlite3 {

   sqlite3_vfs *pVfs;            /* OS Interface */

   int nDb;                      /* Number of backends currently in use */

   Db *aDb;                      /* All backends */

   int flags;                    /* Miscellanous flags. See below */

   int openFlags;                /* Flags passed to sqlite3_vfs.xOpen() */

   int errCode;                  /* Most recent error code (SQLITE_*) */

   int errMask;                  /* & result codes with this before returning */

   u8 autoCommit;                /* The auto-commit flag. */

   u8 temp_store;                /* 1: file 2: memory 0: default */

   u8 mallocFailed;              /* True if we have seen a malloc failure */

   u8 dfltLockMode;              /* Default locking-mode for attached dbs */

   u8 dfltJournalMode;           /* Default journal mode for attached dbs */

   signed char nextAutovac;      /* Autovac setting after VACUUM if >=0 */

   int nextPagesize;             /* Pagesize after VACUUM if >0 */

   int nTable;                   /* Number of tables in the database */

   CollSeq *pDfltColl;           /* The default collating sequence (BINARY) */

   i64 lastRowid;                /* ROWID of most recent insert (see above) */

   i64 priorNewRowid;            /* Last randomly generated ROWID */

   int magic;                    /* Magic number for detect library misuse */

   int nChange;                  /* Value returned by sqlite3_changes() */

   int nTotalChange;             /* Value returned by sqlite3_total_changes() */

   sqlite3_mutex *mutex;         /* Connection mutex */

   int aLimit[SQLITE_N_LIMIT];   /* Limits */

   struct sqlite3InitInfo {      /* Information used during initialization */

     int iDb;                    /* When back is being initialized */

     int newTnum;                /* Rootpage of table being initialized */

     u8 busy;                    /* TRUE if currently initializing */

   } init;

   int nExtension;               /* Number of loaded extensions */

   void **aExtension;            /* Array of shared libraray handles */

   struct Vdbe *pVdbe;           /* List of active virtual machines */

   int activeVdbeCnt;            /* Number of vdbes currently executing */

   void (*xTrace)(void*,const char*);        /* Trace function */

   void *pTraceArg;                          /* Argument to the trace function */

   void (*xProfile)(void*,const char*,u64);  /* Profiling function */

   void *pProfileArg;                        /* Argument to profile function */

   void *pCommitArg;                 /* Argument to xCommitCallback() */   

   int (*xCommitCallback)(void*);    /* Invoked at every commit. */

   void *pRollbackArg;               /* Argument to xRollbackCallback() */   

   void (*xRollbackCallback)(void*); /* Invoked at every commit. */

   void *pUpdateArg;

   void (*xUpdateCallback)(void*,int, const char*,const char*,sqlite_int64);

   void(*xCollNeeded)(void*,sqlite3*,int eTextRep,const char*);

   void(*xCollNeeded16)(void*,sqlite3*,int eTextRep,const void*);

   void *pCollNeededArg;

   sqlite3_value *pErr;          /* Most recent error message */

   char *zErrMsg;                /* Most recent error message (UTF-8 encoded) */

   char *zErrMsg16;              /* Most recent error message (UTF-16 encoded) */

   union {

     volatile int isInterrupted; /* True if sqlite3_interrupt has been called */

     double notUsed1;            /* Spacer */

   } u1;

   Lookaside lookaside;          /* Lookaside malloc configuration */

 #ifndef SQLITE_OMIT_AUTHORIZATION

   int (*xAuth)(void*,int,const char*,const char*,const char*,const char*);

                                 /* Access authorization function */

   void *pAuthArg;               /* 1st argument to the access auth function */

 #endif

 #ifndef SQLITE_OMIT_PROGRESS_CALLBACK

   int (*xProgress)(void *);     /* The progress callback */

   void *pProgressArg;           /* Argument to the progress callback */

   int nProgressOps;             /* Number of opcodes for progress callback */

 #endif

 #ifndef SQLITE_OMIT_VIRTUALTABLE

   Hash aModule;                 /* populated by sqlite3_create_module() */

   Table *pVTab;                 /* vtab with active Connect/Create method */

   sqlite3_vtab **aVTrans;       /* Virtual tables with open transactions */

   int nVTrans;                  /* Allocated size of aVTrans */

 #endif

   FuncDefHash aFunc;            /* Hash table of connection functions */

   Hash aCollSeq;                /* All collating sequences */

   BusyHandler busyHandler;      /* Busy callback */

   int busyTimeout;              /* Busy handler timeout, in msec */

   Db aDbStatic[2];              /* Static space for the 2 default backends */

 #ifdef SQLITE_SSE

   sqlite3_stmt *pFetch;         /* Used by SSE to fetch stored statements */

 #endif

 };

 /*

 ** A macro to discover the encoding of a database.

 */

 #define ENC(db) ((db)->aDb[0].pSchema->enc)

 /*

 ** Possible values for the sqlite.flags and or Db.flags fields.

 **

 ** On sqlite.flags, the SQLITE_InTrans value means that we have

 ** executed a BEGIN.  On Db.flags, SQLITE_InTrans means a statement

 ** transaction is active on that particular database file.

 */

 #define SQLITE_VdbeTrace      0x00000001  /* True to trace VDBE execution */

 #define SQLITE_InTrans        0x00000008  /* True if in a transaction */

 #define SQLITE_InternChanges  0x00000010  /* Uncommitted Hash table changes */

 #define SQLITE_FullColNames   0x00000020  /* Show full column names on SELECT */

 #define SQLITE_ShortColNames  0x00000040  /* Show short columns names */

 #define SQLITE_CountRows      0x00000080  /* Count rows changed by INSERT, */

                                           /*   DELETE, or UPDATE and return */

                                           /*   the count using a callback. */

 #define SQLITE_NullCallback   0x00000100  /* Invoke the callback once if the */

                                           /*   result set is empty */

 #define SQLITE_SqlTrace       0x00000200  /* Debug print SQL as it executes */

 #define SQLITE_VdbeListing    0x00000400  /* Debug listings of VDBE programs */

 #define SQLITE_WriteSchema    0x00000800  /* OK to update SQLITE_MASTER */

 #define SQLITE_NoReadlock     0x00001000  /* Readlocks are omitted when 

                                           ** accessing read-only databases */

 #define SQLITE_IgnoreChecks   0x00002000  /* Do not enforce check constraints */

 #define SQLITE_ReadUncommitted 0x00004000 /* For shared-cache mode */

 #define SQLITE_LegacyFileFmt  0x00008000  /* Create new databases in format 1 */

 #define SQLITE_FullFSync      0x00010000  /* Use full fsync on the backend */

 #define SQLITE_LoadExtension  0x00020000  /* Enable load_extension */

 #define SQLITE_RecoveryMode   0x00040000  /* Ignore schema errors */

 #define SQLITE_SharedCache    0x00080000  /* Cache sharing is enabled */

 #define SQLITE_Vtab           0x00100000  /* There exists a virtual table */

 /*

 ** Possible values for the sqlite.magic field.

 ** The numbers are obtained at random and have no special meaning, other

 ** than being distinct from one another.

 */

 #define SQLITE_MAGIC_OPEN     0xa029a697  /* Database is open */

 #define SQLITE_MAGIC_CLOSED   0x9f3c2d33  /* Database is closed */

 #define SQLITE_MAGIC_SICK     0x4b771290  /* Error and awaiting close */

 #define SQLITE_MAGIC_BUSY     0xf03b7906  /* Database currently in use */

 #define SQLITE_MAGIC_ERROR    0xb5357930  /* An SQLITE_MISUSE error occurred */

 /*

 ** Each SQL function is defined by an instance of the following

 ** structure.  A pointer to this structure is stored in the sqlite.aFunc

 ** hash table.  When multiple functions have the same name, the hash table

 ** points to a linked list of these structures.

 */

 struct FuncDef {

   i16 nArg;            /* Number of arguments.  -1 means unlimited */

   u8 iPrefEnc;         /* Preferred text encoding (SQLITE_UTF8, 16LE, 16BE) */

   u8 flags;            /* Some combination of SQLITE_FUNC_* */

   void *pUserData;     /* User data parameter */

   FuncDef *pNext;      /* Next function with same name */

   void (*xFunc)(sqlite3_context*,int,sqlite3_value**); /* Regular function */

   void (*xStep)(sqlite3_context*,int,sqlite3_value**); /* Aggregate step */

   void (*xFinalize)(sqlite3_context*);                /* Aggregate finializer */

   char *zName;         /* SQL name of the function. */

   FuncDef *pHash;      /* Next with a different name but the same hash */

 };

 /*

 ** Possible values for FuncDef.flags

 */

 #define SQLITE_FUNC_LIKE     0x01 /* Candidate for the LIKE optimization */

 #define SQLITE_FUNC_CASE     0x02 /* Case-sensitive LIKE-type function */

 #define SQLITE_FUNC_EPHEM    0x04 /* Ephermeral.  Delete with VDBE */

 #define SQLITE_FUNC_NEEDCOLL 0x08 /* sqlite3GetFuncCollSeq() might be called */

 /*

 ** The following three macros, FUNCTION(), LIKEFUNC() and AGGREGATE() are

 ** used to create the initializers for the FuncDef structures.

 **

 **   FUNCTION(zName, nArg, iArg, bNC, xFunc)

 **     Used to create a scalar function definition of a function zName 

 **     implemented by C function xFunc that accepts nArg arguments. The

 **     value passed as iArg is cast to a (void*) and made available

 **     as the user-data (sqlite3_user_data()) for the function. If 

 **     argument bNC is true, then the FuncDef.needCollate flag is set.

 **

 **   AGGREGATE(zName, nArg, iArg, bNC, xStep, xFinal)

 **     Used to create an aggregate function definition implemented by

 **     the C functions xStep and xFinal. The first four parameters

 **     are interpreted in the same way as the first 4 parameters to

 **     FUNCTION().

 **

 **   LIKEFUNC(zName, nArg, pArg, flags)

 **     Used to create a scalar function definition of a function zName 

 **     that accepts nArg arguments and is implemented by a call to C 

 **     function likeFunc. Argument pArg is cast to a (void *) and made

 **     available as the function user-data (sqlite3_user_data()). The

 **     FuncDef.flags variable is set to the value passed as the flags

 **     parameter.

 */

 #define FUNCTION(zName, nArg, iArg, bNC, xFunc) \

   {nArg, SQLITE_UTF8, bNC*8, SQLITE_INT_TO_PTR(iArg), 0, xFunc, 0, 0, #zName}

 #define STR_FUNCTION(zName, nArg, pArg, bNC, xFunc) \

   {nArg, SQLITE_UTF8, bNC*8, pArg, 0, xFunc, 0, 0, #zName}

 #define LIKEFUNC(zName, nArg, arg, flags) \

   {nArg, SQLITE_UTF8, flags, (void *)arg, 0, likeFunc, 0, 0, #zName}

 #define AGGREGATE(zName, nArg, arg, nc, xStep, xFinal) \

   {nArg, SQLITE_UTF8, nc*8, SQLITE_INT_TO_PTR(arg), 0, 0, xStep,xFinal, #zName}

 /*

 ** Each SQLite module (virtual table definition) is defined by an

 ** instance of the following structure, stored in the sqlite3.aModule

 ** hash table.

 */

 struct Module {

   const sqlite3_module *pModule;       /* Callback pointers */

   const char *zName;                   /* Name passed to create_module() */

   void *pAux;                          /* pAux passed to create_module() */

   void (*xDestroy)(void *);            /* Module destructor function */

 };

 /*

 ** information about each column of an SQL table is held in an instance

 ** of this structure.

 */

 struct Column {

   char *zName;     /* Name of this column */

   Expr *pDflt;     /* Default value of this column */

   char *zType;     /* Data type for this column */

   char *zColl;     /* Collating sequence.  If NULL, use the default */

   u8 notNull;      /* True if there is a NOT NULL constraint */

   u8 isPrimKey;    /* True if this column is part of the PRIMARY KEY */

   char affinity;   /* One of the SQLITE_AFF_... values */

 #ifndef SQLITE_OMIT_VIRTUALTABLE

   u8 isHidden;     /* True if this column is 'hidden' */

 #endif

 };

 /*

 ** A "Collating Sequence" is defined by an instance of the following

 ** structure. Conceptually, a collating sequence consists of a name and

 ** a comparison routine that defines the order of that sequence.

 **

 ** There may two seperate implementations of the collation function, one

 ** that processes text in UTF-8 encoding (CollSeq.xCmp) and another that

 ** processes text encoded in UTF-16 (CollSeq.xCmp16), using the machine

 ** native byte order. When a collation sequence is invoked, SQLite selects

 ** the version that will require the least expensive encoding

 ** translations, if any.

 **

 ** The CollSeq.pUser member variable is an extra parameter that passed in

 ** as the first argument to the UTF-8 comparison function, xCmp.

 ** CollSeq.pUser16 is the equivalent for the UTF-16 comparison function,

 ** xCmp16.

 **

 ** If both CollSeq.xCmp and CollSeq.xCmp16 are NULL, it means that the

 ** collating sequence is undefined.  Indices built on an undefined

 ** collating sequence may not be read or written.

 */

 struct CollSeq {

   char *zName;          /* Name of the collating sequence, UTF-8 encoded */

   u8 enc;               /* Text encoding handled by xCmp() */

   u8 type;              /* One of the SQLITE_COLL_... values below */

   void *pUser;          /* First argument to xCmp() */

   int (*xCmp)(void*,int, const void*, int, const void*);

   void (*xDel)(void*);  /* Destructor for pUser */

 };

 /*

 ** Allowed values of CollSeq.type:

 */

 #define SQLITE_COLL_BINARY  1  /* The default memcmp() collating sequence */

 #define SQLITE_COLL_NOCASE  2  /* The built-in NOCASE collating sequence */

 #define SQLITE_COLL_REVERSE 3  /* The built-in REVERSE collating sequence */

 #define SQLITE_COLL_USER    0  /* Any other user-defined collating sequence */

 /*

 ** A sort order can be either ASC or DESC.

 */

 #define SQLITE_SO_ASC       0  /* Sort in ascending order */

 #define SQLITE_SO_DESC      1  /* Sort in ascending order */

 /*

 ** Column affinity types.

 **

 ** These used to have mnemonic name like 'i' for SQLITE_AFF_INTEGER and

 ** 't' for SQLITE_AFF_TEXT.  But we can save a little space and improve

 ** the speed a little by numbering the values consecutively.  

 **

 ** But rather than start with 0 or 1, we begin with 'a'.  That way,

 ** when multiple affinity types are concatenated into a string and

 ** used as the P4 operand, they will be more readable.

 **

 ** Note also that the numeric types are grouped together so that testing

 ** for a numeric type is a single comparison.

 */

 #define SQLITE_AFF_TEXT     'a'

 #define SQLITE_AFF_NONE     'b'

 #define SQLITE_AFF_NUMERIC  'c'

 #define SQLITE_AFF_INTEGER  'd'

 #define SQLITE_AFF_REAL     'e'

 #define sqlite3IsNumericAffinity(X)  ((X)>=SQLITE_AFF_NUMERIC)

 /*

 ** The SQLITE_AFF_MASK values masks off the significant bits of an

 ** affinity value. 

 */

 #define SQLITE_AFF_MASK     0x67

 /*

 ** Additional bit values that can be ORed with an affinity without

 ** changing the affinity.

 */

 #define SQLITE_JUMPIFNULL   0x08  /* jumps if either operand is NULL */

 #define SQLITE_STOREP2      0x10  /* Store result in reg[P2] rather than jump */

 /*

 ** Each SQL table is represented in memory by an instance of the

 ** following structure.

 **

 ** Table.zName is the name of the table.  The case of the original

 ** CREATE TABLE statement is stored, but case is not significant for

 ** comparisons.

 **

 ** Table.nCol is the number of columns in this table.  Table.aCol is a

 ** pointer to an array of Column structures, one for each column.

 **

 ** If the table has an INTEGER PRIMARY KEY, then Table.iPKey is the index of

 ** the column that is that key.   Otherwise Table.iPKey is negative.  Note

 ** that the datatype of the PRIMARY KEY must be INTEGER for this field to

 ** be set.  An INTEGER PRIMARY KEY is used as the rowid for each row of

 ** the table.  If a table has no INTEGER PRIMARY KEY, then a random rowid

 ** is generated for each row of the table.  TF_HasPrimaryKey is set if

 ** the table has any PRIMARY KEY, INTEGER or otherwise.

 **

 ** Table.tnum is the page number for the root BTree page of the table in the

 ** database file.  If Table.iDb is the index of the database table backend

 ** in sqlite.aDb[].  0 is for the main database and 1 is for the file that

 ** holds temporary tables and indices.  If TF_Ephemeral is set

 ** then the table is stored in a file that is automatically deleted

 ** when the VDBE cursor to the table is closed.  In this case Table.tnum 

 ** refers VDBE cursor number that holds the table open, not to the root

 ** page number.  Transient tables are used to hold the results of a

 ** sub-query that appears instead of a real table name in the FROM clause 

 ** of a SELECT statement.

 */

 struct Table {

   sqlite3 *db;         /* Associated database connection.  Might be NULL. */

   char *zName;         /* Name of the table or view */

   int iPKey;           /* If not negative, use aCol[iPKey] as the primary key */

   int nCol;            /* Number of columns in this table */

   Column *aCol;        /* Information about each column */

   Index *pIndex;       /* List of SQL indexes on this table. */

   int tnum;            /* Root BTree node for this table (see note above) */

   Select *pSelect;     /* NULL for tables.  Points to definition if a view. */

   u16 nRef;            /* Number of pointers to this Table */

   u8 tabFlags;         /* Mask of TF_* values */

   u8 keyConf;          /* What to do in case of uniqueness conflict on iPKey */

   Trigger *pTrigger;   /* List of SQL triggers on this table */

   FKey *pFKey;         /* Linked list of all foreign keys in this table */

   char *zColAff;       /* String defining the affinity of each column */

 #ifndef SQLITE_OMIT_CHECK

   Expr *pCheck;        /* The AND of all CHECK constraints */

 #endif

 #ifndef SQLITE_OMIT_ALTERTABLE

   int addColOffset;    /* Offset in CREATE TABLE stmt to add a new column */

 #endif

 #ifndef SQLITE_OMIT_VIRTUALTABLE

   Module *pMod;        /* Pointer to the implementation of the module */

   sqlite3_vtab *pVtab; /* Pointer to the module instance */

   int nModuleArg;      /* Number of arguments to the module */

   char **azModuleArg;  /* Text of all module args. [0] is module name */

 #endif

   Schema *pSchema;     /* Schema that contains this table */

   Table *pNextZombie;  /* Next on the Parse.pZombieTab list */

 };

 /*

 ** Allowed values for Tabe.tabFlags.

 */

 #define TF_Readonly        0x01    /* Read-only system table */

 #define TF_Ephemeral       0x02    /* An emphermal table */

 #define TF_HasPrimaryKey   0x04    /* Table has a primary key */

 #define TF_Autoincrement   0x08    /* Integer primary key is autoincrement */

 #define TF_Virtual         0x10    /* Is a virtual table */

 #define TF_NeedMetadata    0x20    /* aCol[].zType and aCol[].pColl missing */

 /*

 ** Test to see whether or not a table is a virtual table.  This is

 ** done as a macro so that it will be optimized out when virtual

 ** table support is omitted from the build.

 */

 #ifndef SQLITE_OMIT_VIRTUALTABLE

 #  define IsVirtual(X)      (((X)->tabFlags & TF_Virtual)!=0)

 #  define IsHiddenColumn(X) ((X)->isHidden)

 #else

 #  define IsVirtual(X)      0

 #  define IsHiddenColumn(X) 0

 #endif

 /*

 ** Each foreign key constraint is an instance of the following structure.

 **

 ** A foreign key is associated with two tables.  The "from" table is

 ** the table that contains the REFERENCES clause that creates the foreign

 ** key.  The "to" table is the table that is named in the REFERENCES clause.

 ** Consider this example:

 **

 **     CREATE TABLE ex1(

 **       a INTEGER PRIMARY KEY,

 **       b INTEGER CONSTRAINT fk1 REFERENCES ex2(x)

 **     );

 **

 ** For foreign key "fk1", the from-table is "ex1" and the to-table is "ex2".

 **

 ** Each REFERENCES clause generates an instance of the following structure

 ** which is attached to the from-table.  The to-table need not exist when

 ** the from-table is created.  The existance of the to-table is not checked

 ** until an attempt is made to insert data into the from-table.

 **

 ** The sqlite.aFKey hash table stores pointers to this structure

 ** given the name of a to-table.  For each to-table, all foreign keys

 ** associated with that table are on a linked list using the FKey.pNextTo

 ** field.

 */

 struct FKey {

   Table *pFrom;     /* The table that constains the REFERENCES clause */

   FKey *pNextFrom;  /* Next foreign key in pFrom */

   char *zTo;        /* Name of table that the key points to */

   FKey *pNextTo;    /* Next foreign key that points to zTo */

   int nCol;         /* Number of columns in this key */

   struct sColMap {  /* Mapping of columns in pFrom to columns in zTo */

     int iFrom;         /* Index of column in pFrom */

     char *zCol;        /* Name of column in zTo.  If 0 use PRIMARY KEY */

   } *aCol;          /* One entry for each of nCol column s */

   u8 isDeferred;    /* True if constraint checking is deferred till COMMIT */

   u8 updateConf;    /* How to resolve conflicts that occur on UPDATE */

   u8 deleteConf;    /* How to resolve conflicts that occur on DELETE */

   u8 insertConf;    /* How to resolve conflicts that occur on INSERT */

 };

 /*

 ** SQLite supports many different ways to resolve a constraint

 ** error.  ROLLBACK processing means that a constraint violation

 ** causes the operation in process to fail and for the current transaction

 ** to be rolled back.  ABORT processing means the operation in process

 ** fails and any prior changes from that one operation are backed out,

 ** but the transaction is not rolled back.  FAIL processing means that

 ** the operation in progress stops and returns an error code.  But prior

 ** changes due to the same operation are not backed out and no rollback

 ** occurs.  IGNORE means that the particular row that caused the constraint

 ** error is not inserted or updated.  Processing continues and no error

 ** is returned.  REPLACE means that preexisting database rows that caused

 ** a UNIQUE constraint violation are removed so that the new insert or

 ** update can proceed.  Processing continues and no error is reported.

 **

 ** RESTRICT, SETNULL, and CASCADE actions apply only to foreign keys.

 ** RESTRICT is the same as ABORT for IMMEDIATE foreign keys and the

 ** same as ROLLBACK for DEFERRED keys.  SETNULL means that the foreign

 ** key is set to NULL.  CASCADE means that a DELETE or UPDATE of the

 ** referenced table row is propagated into the row that holds the

 ** foreign key.

 ** 

 ** The following symbolic values are used to record which type

 ** of action to take.

 */

 #define OE_None     0   /* There is no constraint to check */

 #define OE_Rollback 1   /* Fail the operation and rollback the transaction */

 #define OE_Abort    2   /* Back out changes but do no rollback transaction */

 #define OE_Fail     3   /* Stop the operation but leave all prior changes */

 #define OE_Ignore   4   /* Ignore the error. Do not do the INSERT or UPDATE */

 #define OE_Replace  5   /* Delete existing record, then do INSERT or UPDATE */

 #define OE_Restrict 6   /* OE_Abort for IMMEDIATE, OE_Rollback for DEFERRED */

 #define OE_SetNull  7   /* Set the foreign key value to NULL */

 #define OE_SetDflt  8   /* Set the foreign key value to its default */

 #define OE_Cascade  9   /* Cascade the changes */

 #define OE_Default  99  /* Do whatever the default action is */

 /*

 ** An instance of the following structure is passed as the first

 ** argument to sqlite3VdbeKeyCompare and is used to control the 

 ** comparison of the two index keys.

 */

 struct KeyInfo {

   sqlite3 *db;        /* The database connection */

   u8 enc;             /* Text encoding - one of the TEXT_Utf* values */

   u16 nField;         /* Number of entries in aColl[] */

   u8 *aSortOrder;     /* If defined an aSortOrder[i] is true, sort DESC */

   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 disassemblied by the

 ** OP_Column opcode.

 **

 ** This structure holds a record that has already been disassembled

 ** into its constitutent fields.

 */

 struct UnpackedRecord {

   KeyInfo *pKeyInfo;  /* Collation and sort-order information */

   u16 nField;         /* Number of entries in apMem[] */

   u16 flags;          /* Boolean settings.  UNPACKED_... below */

   Mem *aMem;          /* Values */

 };

 /*

 ** Allowed values of UnpackedRecord.flags

 */

 #define UNPACKED_NEED_FREE     0x0001  /* Memory is from sqlite3Malloc() */

 #define UNPACKED_NEED_DESTROY  0x0002  /* apMem[]s should all be destroyed */

 #define UNPACKED_IGNORE_ROWID  0x0004  /* Ignore trailing rowid on key1 */

 #define UNPACKED_INCRKEY       0x0008  /* Make this key an epsilon larger */

 #define UNPACKED_PREFIX_MATCH  0x0010  /* A prefix match is considered OK */

 /*

 ** 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:

 **

 **     CREATE TABLE Ex1(c1 int, c2 int, c3 text);

 **     CREATE INDEX Ex2 ON Ex1(c3,c1);

 **

 ** In the Table structure describing Ex1, nCol==3 because there are

 ** three columns in the table.  In the Index structure describing

 ** Ex2, nColumn==2 since 2 of the 3 columns of Ex1 are indexed.

 ** The value of aiColumn is {2, 0}.  aiColumn[0]==2 because the 

 ** first column to be indexed (c3) has an index of 2 in Ex1.aCol[].

 ** The second column to be indexed (c1) has an index of 0 in

 ** Ex1.aCol[], hence Ex2.aiColumn[1]==0.

 **

 ** The Index.onError field determines whether or not the indexed columns

 ** must be unique and what to do if they are not.  When Index.onError=OE_None,

 ** it means this is not a unique index.  Otherwise it is a unique index

 ** and the value of Index.onError indicate the which conflict resolution 

 ** algorithm to employ whenever an attempt is made to insert a non-unique

 ** element.

 */

 struct Index {

   char *zName;     /* Name of this index */

   int nColumn;     /* Number of columns in the table used by this index */

   int *aiColumn;   /* Which columns are used by this index.  1st is 0 */

   unsigned *aiRowEst; /* Result of ANALYZE: Est. rows selected by each column */

   Table *pTable;   /* The SQL table being indexed */

   int tnum;        /* Page containing root of this index in database file */

   u8 onError;      /* OE_Abort, OE_Ignore, OE_Replace, or OE_None */

   u8 autoIndex;    /* True if is automatically created (ex: by UNIQUE) */

   char *zColAff;   /* String defining the affinity of each column */

   Index *pNext;    /* The next index associated with the same table */

   Schema *pSchema; /* Schema containing this index */

   u8 *aSortOrder;  /* Array of size Index.nColumn. True==DESC, False==ASC */

   char **azColl;   /* Array of collation sequence names for index */

 };

 /*

 ** Each token coming out of the lexer is an instance of

 ** this structure.  Tokens are also used as part of an expression.

 **

 ** Note if Token.z==0 then Token.dyn and Token.n are undefined and

 ** may contain random values.  Do not make any assuptions about Token.dyn

 ** and Token.n when Token.z==0.

 */

 struct Token {

   const unsigned char *z; /* Text of the token.  Not NULL-terminated! */

   unsigned dyn  : 1;      /* True for malloced memory, false for static */

   unsigned n    : 31;     /* Number of characters in this token */

 };

 /*

 ** An instance of this structure contains information needed to generate

 ** code for a SELECT that contains aggregate functions.

 **

 ** If Expr.op==TK_AGG_COLUMN or TK_AGG_FUNCTION then Expr.pAggInfo is a

 ** pointer to this structure.  The Expr.iColumn field is the index in

 ** AggInfo.aCol[] or AggInfo.aFunc[] of information needed to generate

 ** code for that node.

 **

 ** AggInfo.pGroupBy and AggInfo.aFunc.pExpr point to fields within the

 ** original Select structure that describes the SELECT statement.  These

 ** fields do not need to be freed when deallocating the AggInfo structure.

 */

 struct AggInfo {

   u8 directMode;          /* Direct rendering mode means take data directly

                           ** from source tables rather than from accumulators */

   u8 useSortingIdx;       /* In direct mode, reference the sorting index rather

                           ** than the source table */

   int sortingIdx;         /* Cursor number of the sorting index */

   ExprList *pGroupBy;     /* The group by clause */

   int nSortingColumn;     /* Number of columns in the sorting index */

   struct AggInfo_col {    /* For each column used in source tables */

     Table *pTab;             /* Source table */

     int iTable;              /* Cursor number of the source table */

     int iColumn;             /* Column number within the source table */

     int iSorterColumn;       /* Column number in the sorting index */

     int iMem;                /* Memory location that acts as accumulator */

     Expr *pExpr;             /* The original expression */

   } *aCol;

   int nColumn;            /* Number of used entries in aCol[] */

   int nColumnAlloc;       /* Number of slots allocated for aCol[] */

   int nAccumulator;       /* Number of columns that show through to the output.

                           ** Additional columns are used only as parameters to

                           ** aggregate functions */

   struct AggInfo_func {   /* For each aggregate function */

     Expr *pExpr;             /* Expression encoding the function */

     FuncDef *pFunc;          /* The aggregate function implementation */

     int iMem;                /* Memory location that acts as accumulator */

     int iDistinct;           /* Ephermeral table used to enforce DISTINCT */

   } *aFunc;

   int nFunc;              /* Number of entries in aFunc[] */

   int nFuncAlloc;         /* Number of slots allocated for aFunc[] */

 };

 /*

 ** Each node of an expression in the parse tree is an instance

 ** of this structure.

 **

 ** Expr.op is the opcode.  The integer parser token codes are reused

 ** as opcodes here.  For example, the parser defines TK_GE to be an integer

 ** code representing the ">=" operator.  This same integer code is reused

 ** to represent the greater-than-or-equal-to operator in the expression

 ** tree.

 **

 ** Expr.pRight and Expr.pLeft are subexpressions.  Expr.pList is a list

 ** of argument if the expression is a function.

 **

 ** Expr.token is the operator token for this node.  For some expressions

 ** that have subexpressions, Expr.token can be the complete text that gave

 ** rise to the Expr.  In the latter case, the token is marked as being

 ** a compound token.

 **

 ** An expression of the form ID or ID.ID refers to a column in a table.

 ** For such expressions, Expr.op is set to TK_COLUMN and Expr.iTable is

 ** the integer cursor number of a VDBE cursor pointing to that table and

 ** Expr.iColumn is the column number for the specific column.  If the

 ** expression is used as a result in an aggregate SELECT, then the

 ** value is also stored in the Expr.iAgg column in the aggregate so that

 ** it can be accessed after all aggregates are computed.

 **

 ** If the expression is a function, the Expr.iTable is an integer code

 ** representing which function.  If the expression is an unbound variable

 ** marker (a question mark character '?' in the original SQL) then the

 ** Expr.iTable holds the index number for that variable.

 **

 ** If the expression is a subquery then Expr.iColumn holds an integer

 ** register number containing the result of the subquery.  If the

 ** subquery gives a constant result, then iTable is -1.  If the subquery

 ** gives a different answer at different times during statement processing

 ** then iTable is the address of a subroutine that computes the subquery.

 **

 ** The Expr.pSelect field points to a SELECT statement.  The SELECT might

 ** be the right operand of an IN operator.  Or, if a scalar SELECT appears

 ** in an expression the opcode is TK_SELECT and Expr.pSelect is the only

 ** operand.

 **

 ** If the Expr is of type OP_Column, and the table it is selecting from

 ** is a disk table or the "old.*" pseudo-table, then pTab points to the

 ** corresponding table definition.

 */

 struct Expr {

   u8 op;                 /* Operation performed by this node */

   char affinity;         /* The affinity of the column or 0 if not a column */

   u16 flags;             /* Various flags.  See below */

   CollSeq *pColl;        /* The collation type of the column or 0 */

   Expr *pLeft, *pRight;  /* Left and right subnodes */

   ExprList *pList;       /* A list of expressions used as function arguments

                          ** or in "<expr> IN (<expr-list)" */

   Token token;           /* An operand token */

   Token span;            /* Complete text of the expression */

   int iTable, iColumn;   /* When op==TK_COLUMN, then this expr node means the

                          ** iColumn-th field of the iTable-th table. */

   AggInfo *pAggInfo;     /* Used by TK_AGG_COLUMN and TK_AGG_FUNCTION */

   int iAgg;              /* Which entry in pAggInfo->aCol[] or ->aFunc[] */

   int iRightJoinTable;   /* If EP_FromJoin, the right table of the join */

   Select *pSelect;       /* When the expression is a sub-select.  Also the

                          ** right side of "<expr> IN (<select>)" */

   Table *pTab;           /* Table for TK_COLUMN expressions. */

 #if SQLITE_MAX_EXPR_DEPTH>0

   int nHeight;           /* Height of the tree headed by this node */

 #endif

 };

 /*

 ** The following are the meanings of bits in the Expr.flags field.

 */

 #define EP_FromJoin   0x0001  /* Originated in ON or USING clause of a join */

 #define EP_Agg        0x0002  /* Contains one or more aggregate functions */

 #define EP_Resolved   0x0004  /* IDs have been resolved to COLUMNs */

 #define EP_Error      0x0008  /* Expression contains one or more errors */

 #define EP_Distinct   0x0010  /* Aggregate function with DISTINCT keyword */

 #define EP_VarSelect  0x0020  /* pSelect is correlated, not constant */

 #define EP_Dequoted   0x0040  /* True if the string has been dequoted */

 #define EP_InfixFunc  0x0080  /* True for an infix function: LIKE, GLOB, etc */

 #define EP_ExpCollate 0x0100  /* Collating sequence specified explicitly */

 #define EP_AnyAff     0x0200  /* Can take a cached column of any affinity */

 #define EP_FixedDest  0x0400  /* Result needed in a specific register */

 #define EP_IntValue   0x0800  /* Integer value contained in iTable */

 /*

 ** These macros can be used to test, set, or clear bits in the 

 ** Expr.flags field.

 */

 #define ExprHasProperty(E,P)     (((E)->flags&(P))==(P))

 #define ExprHasAnyProperty(E,P)  (((E)->flags&(P))!=0)

 #define ExprSetProperty(E,P)     (E)->flags|=(P)

 #define ExprClearProperty(E,P)   (E)->flags&=~(P)

 /*

 ** A list of expressions.  Each expression may optionally have a

 ** name.  An expr/name combination can be used in several ways, such

 ** as the list of "expr AS ID" fields following a "SELECT" or in the

 ** list of "ID = expr" items in an UPDATE.  A list of expressions can

 ** also be used as the argument to a function, in which case the a.zName

 ** field is not used.

 */

 struct ExprList {

   int nExpr;             /* Number of expressions on the list */

   int nAlloc;            /* Number of entries allocated below */

   int iECursor;          /* VDBE Cursor associated with this ExprList */

   struct ExprList_item {

     Expr *pExpr;           /* The list of expressions */

     char *zName;           /* Token associated with this expression */

     u8 sortOrder;          /* 1 for DESC or 0 for ASC */

     u8 done;               /* A flag to indicate when processing is finished */

     u16 iCol;              /* For ORDER BY, column number in result set */

     u16 iAlias;            /* Index into Parse.aAlias[] for zName */

   } *a;                  /* One entry for each expression */

 };

 /*

 ** An instance of this structure can hold a simple list of identifiers,

 ** such as the list "a,b,c" in the following statements:

 **

 **      INSERT INTO t(a,b,c) VALUES ...;

 **      CREATE INDEX idx ON t(a,b,c);

 **      CREATE TRIGGER trig BEFORE UPDATE ON t(a,b,c) ...;

 **

 ** The IdList.a.idx field is used when the IdList represents the list of

 ** column names after a table name in an INSERT statement.  In the statement

 **

 **     INSERT INTO t(a,b,c) ...

 **

 ** If "a" is the k-th column of table "t", then IdList.a[0].idx==k.

 */

 struct IdList {

   struct IdList_item {

     char *zName;      /* Name of the identifier */

     int idx;          /* Index in some Table.aCol[] of a column named zName */

   } *a;

   int nId;         /* Number of identifiers on the list */

   int nAlloc;      /* Number of entries allocated for a[] below */

 };

 /*

 ** The bitmask datatype defined below is used for various optimizations.

 **

 ** Changing this from a 64-bit to a 32-bit type limits the number of

 ** tables in a join to 32 instead of 64.  But it also reduces the size

 ** of the library by 738 bytes on ix86.

 */

 typedef u64 Bitmask;

 /*

 ** The following structure describes the FROM clause of a SELECT statement.

 ** Each table or subquery in the FROM clause is a separate element of

 ** the SrcList.a[] array.

 **

 ** With the addition of multiple database support, the following structure

 ** can also be used to describe a particular table such as the table that

 ** is modified by an INSERT, DELETE, or UPDATE statement.  In standard SQL,

 ** such a table must be a simple name: ID.  But in SQLite, the table can

 ** now be identified by a database name, a dot, then the table name: ID.ID.

 **

 ** The jointype starts out showing the join type between the current table

 ** and the next table on the list.  The parser builds the list this way.

 ** But sqlite3SrcListShiftJoinType() later shifts the jointypes so that each

 ** jointype expresses the join between the table and the previous table.

 */

 struct SrcList {

   i16 nSrc;        /* Number of tables or subqueries in the FROM clause */

   i16 nAlloc;      /* Number of entries allocated in a[] below */

   struct SrcList_item {

     char *zDatabase;  /* Name of database holding this table */

     char *zName;      /* Name of the table */

     char *zAlias;     /* The "B" part of a "A AS B" phrase.  zName is the "A" */

     Table *pTab;      /* An SQL table corresponding to zName */

     Select *pSelect;  /* A SELECT statement used in place of a table name */

     u8 isPopulated;   /* Temporary table associated with SELECT is populated */

     u8 jointype;      /* Type of join between this able and the previous */

     int iCursor;      /* The VDBE cursor number used to access this table */

     Expr *pOn;        /* The ON clause of a join */

     IdList *pUsing;   /* The USING clause of a join */

     Bitmask colUsed;  /* Bit N (1<<N) set if column N or pTab is used */

     u8 notIndexed;    /* True if there is a NOT INDEXED clause */

     char *zIndex;     /* Identifier from "INDEXED BY <zIndex>" clause */

     Index *pIndex;    /* Index structure corresponding to zIndex, if any */

   } a[1];             /* One entry for each identifier on the list */

 };

 /*

 ** Permitted values of the SrcList.a.jointype field

 */

 #define JT_INNER     0x0001    /* Any kind of inner or cross join */

 #define JT_CROSS     0x0002    /* Explicit use of the CROSS keyword */

 #define JT_NATURAL   0x0004    /* True for a "natural" join */

 #define JT_LEFT      0x0008    /* Left outer join */

 #define JT_RIGHT     0x0010    /* Right outer join */

 #define JT_OUTER     0x0020    /* The "OUTER" keyword is present */

 #define JT_ERROR     0x0040    /* unknown or unsupported join type */

 /*

 ** For each nested loop in a WHERE clause implementation, the WhereInfo

 ** structure contains a single instance of this structure.  This structure

 ** is intended to be private the the where.c module and should not be

 ** access or modified by other modules.

 **

 ** The pIdxInfo and pBestIdx fields are used to help pick the best

 ** index on a virtual table.  The pIdxInfo pointer contains indexing

 ** information for the i-th table in the FROM clause before reordering.

 ** All the pIdxInfo pointers are freed by whereInfoFree() in where.c.

 ** The pBestIdx pointer is a copy of pIdxInfo for the i-th table after

 ** FROM clause ordering.  This is a little confusing so I will repeat

 ** it in different words.  WhereInfo.a[i].pIdxInfo is index information 

 ** for WhereInfo.pTabList.a[i].  WhereInfo.a[i].pBestInfo is the

 ** index information for the i-th loop of the join.  pBestInfo is always

 ** either NULL or a copy of some pIdxInfo.  So for cleanup it is 

 ** sufficient to free all of the pIdxInfo pointers.

 ** 

 */

 struct WhereLevel {

   int iFrom;            /* Which entry in the FROM clause */

   int flags;            /* Flags associated with this level */

   int iMem;             /* First memory cell used by this level */

   int iLeftJoin;        /* Memory cell used to implement LEFT OUTER JOIN */

   Index *pIdx;          /* Index used.  NULL if no index */

   int iTabCur;          /* The VDBE cursor used to access the table */

   int iIdxCur;          /* The VDBE cursor used to acesss pIdx */

   int brk;              /* Jump here to break out of the loop */

   int nxt;              /* Jump here to start the next IN combination */

   int cont;             /* Jump here to continue with the next loop cycle */

   int top;              /* First instruction of interior of the loop */

   int op, p1, p2, p5;   /* Opcode used to terminate the loop */

   int nEq;              /* Number of == or IN constraints on this loop */

   int nIn;              /* Number of IN operators constraining this loop */

   struct InLoop {

     int iCur;              /* The VDBE cursor used by this IN operator */

     int topAddr;           /* Top of the IN loop */

   } *aInLoop;           /* Information about each nested IN operator */

   sqlite3_index_info *pBestIdx;  /* Index information for this level */

   /* The following field is really not part of the current level.  But

   ** we need a place to cache index information for each table in the

   ** FROM clause and the WhereLevel structure is a convenient place.

   */

   sqlite3_index_info *pIdxInfo;  /* Index info for n-th source table */

 };

 /*

 ** Flags appropriate for the wflags parameter of sqlite3WhereBegin().

 */

 #define WHERE_ORDERBY_NORMAL     0   /* No-op */

 #define WHERE_ORDERBY_MIN        1   /* ORDER BY processing for min() func */

 #define WHERE_ORDERBY_MAX        2   /* ORDER BY processing for max() func */

 #define WHERE_ONEPASS_DESIRED    4   /* Want to do one-pass UPDATE/DELETE */

 /*

 ** 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.

 */

 struct WhereInfo {

   Parse *pParse;       /* Parsing and code generating context */

   u8 okOnePass;        /* Ok to use one-pass algorithm for UPDATE or DELETE */

   SrcList *pTabList;   /* List of tables in the join */

   int iTop;            /* The very beginning of the WHERE loop */

   int iContinue;       /* Jump here to continue with next record */

   int iBreak;          /* Jump here to break out of the loop */

   int nLevel;          /* Number of nested loop */

   sqlite3_index_info **apInfo;  /* Array of pointers to index info structures */

   WhereLevel a[1];     /* Information about each nest loop in the WHERE */

 };

 /*

 ** A NameContext defines a context in which to resolve table and column

 ** names.  The context consists of a list of tables (the pSrcList) field and

 ** a list of named expression (pEList).  The named expression list may

 ** be NULL.  The pSrc corresponds to the FROM clause of a SELECT or

 ** to the table being operated on by INSERT, UPDATE, or DELETE.  The

 ** pEList corresponds to the result set of a SELECT and is NULL for

 ** other statements.

 **

 ** NameContexts can be nested.  When resolving names, the inner-most 

 ** context is searched first.  If no match is found, the next outer

 ** context is checked.  If there is still no match, the next context

 ** is checked.  This process continues until either a match is found

 ** or all contexts are check.  When a match is found, the nRef member of

 ** the context containing the match is incremented. 

 **

 ** Each subquery gets a new NameContext.  The pNext field points to the

 ** NameContext in the parent query.  Thus the process of scanning the

 ** NameContext list corresponds to searching through successively outer

 ** subqueries looking for a match.

 */

 struct NameContext {

   Parse *pParse;       /* The parser */

   SrcList *pSrcList;   /* One or more tables used to resolve names */

   ExprList *pEList;    /* Optional list of named expressions */

   int nRef;            /* Number of names resolved by this context */

   int nErr;            /* Number of errors encountered while resolving names */

   u8 allowAgg;         /* Aggregate functions allowed here */

   u8 hasAgg;           /* True if aggregates are seen */

   u8 isCheck;          /* True if resolving names in a CHECK constraint */

   int nDepth;          /* Depth of subquery recursion. 1 for no recursion */

   AggInfo *pAggInfo;   /* Information about aggregates at this level */

   NameContext *pNext;  /* Next outer name context.  NULL for outermost */

 };

 /*

 ** An instance of the following structure contains all information

 ** needed to generate code for a single SELECT statement.

 **

 ** nLimit is set to -1 if there is no LIMIT clause.  nOffset is set to 0.

 ** If there is a LIMIT clause, the parser sets nLimit to the value of the

 ** limit and nOffset to the value of the offset (or 0 if there is not

 ** offset).  But later on, nLimit and nOffset become the memory locations

 ** in the VDBE that record the limit and offset counters.

 **

 ** addrOpenEphm[] entries contain the address of OP_OpenEphemeral opcodes.

 ** These addresses must be stored so that we can go back and fill in

 ** the P4_KEYINFO and P2 parameters later.  Neither the KeyInfo nor

 ** the number of columns in P2 can be computed at the same time

 ** as the OP_OpenEphm instruction is coded because not

 ** enough information about the compound query is known at that point.

 ** The KeyInfo for addrOpenTran[0] and [1] contains collating sequences

 ** for the result set.  The KeyInfo for addrOpenTran[2] contains collating

 ** sequences for the ORDER BY clause.

 */

 struct Select {

   ExprList *pEList;      /* The fields of the result */

   u8 op;                 /* One of: TK_UNION TK_ALL TK_INTERSECT TK_EXCEPT */

   char affinity;         /* MakeRecord with this affinity for SRT_Set */

   u16 selFlags;          /* Various SF_* values */

   SrcList *pSrc;         /* The FROM clause */

   Expr *pWhere;          /* The WHERE clause */

   ExprList *pGroupBy;    /* The GROUP BY clause */

   Expr *pHaving;         /* The HAVING clause */

   ExprList *pOrderBy;    /* The ORDER BY clause */

   Select *pPrior;        /* Prior select in a compound select statement */

   Select *pNext;         /* Next select to the left in a compound */

   Select *pRightmost;    /* Right-most select in a compound select statement */

   Expr *pLimit;          /* LIMIT expression. NULL means not used. */

   Expr *pOffset;         /* OFFSET expression. NULL means not used. */

   int iLimit, iOffset;   /* Memory registers holding LIMIT & OFFSET counters */

   int addrOpenEphm[3];   /* OP_OpenEphem opcodes related to this select */

 };

 /*

 ** Allowed values for Select.selFlags.  The "SF" prefix stands for

 ** "Select Flag".

 */

 #define SF_Distinct        0x0001  /* Output should be DISTINCT */

 #define SF_Resolved        0x0002  /* Identifiers have been resolved */

 #define SF_Aggregate       0x0004  /* Contains aggregate functions */

 #define SF_UsesEphemeral   0x0008  /* Uses the OpenEphemeral opcode */

 #define SF_Expanded        0x0010  /* sqlite3SelectExpand() called on this */

 #define SF_HasTypeInfo     0x0020  /* FROM subqueries have Table metadata */

 /*

 ** The results of a select can be distributed in several ways.  The

 ** "SRT" prefix means "SELECT Result Type".

 */

 #define SRT_Union        1  /* Store result as keys in an index */

 #define SRT_Except       2  /* Remove result from a UNION index */

 #define SRT_Exists       3  /* Store 1 if the result is not empty */

 #define SRT_Discard      4  /* Do not save the results anywhere */

 /* The ORDER BY clause is ignored for all of the above */

 #define IgnorableOrderby(X) ((X->eDest)<=SRT_Discard)

 #define SRT_Output       5  /* Output each row of result */

 #define SRT_Mem          6  /* Store result in a memory cell */

 #define SRT_Set          7  /* Store results as keys in an index */

 #define SRT_Table        8  /* Store result as data with an automatic rowid */

 #define SRT_EphemTab     9  /* Create transient tab and store like SRT_Table */

 #define SRT_Coroutine   10  /* Generate a single row of result */

 /*

 ** A structure used to customize the behaviour of sqlite3Select(). See

 ** comments above sqlite3Select() for details.

 */

 typedef struct SelectDest SelectDest;

 struct SelectDest {

   u8 eDest;         /* How to dispose of the results */

   u8 affinity;      /* Affinity used when eDest==SRT_Set */

   int iParm;        /* A parameter used by the eDest disposal method */

   int iMem;         /* Base register where results are written */

   int nMem;         /* Number of registers allocated */

 };

 /*

 ** An SQL parser context.  A copy of this structure is passed through

 ** the parser and down into all the parser action routine in order to

 ** carry around information that is global to the entire parse.

 **

 ** The structure is divided into two parts.  When the parser and code

 ** generate call themselves recursively, the first part of the structure

 ** is constant but the second part is reset at the beginning and end of

 ** each recursion.

 **

 ** The nTableLock and aTableLock variables are only used if the shared-cache 

 ** feature is enabled (if sqlite3Tsd()->useSharedData is true). They are

 ** used to store the set of table-locks required by the statement being

 ** compiled. Function sqlite3TableLock() is used to add entries to the

 ** list.

 */

 struct Parse {

   sqlite3 *db;         /* The main database structure */

   int rc;              /* Return code from execution */

   char *zErrMsg;       /* An error message */

   Vdbe *pVdbe;         /* An engine for executing database bytecode */

   u8 colNamesSet;      /* TRUE after OP_ColumnName has been issued to pVdbe */

   u8 nameClash;        /* A permanent table name clashes with temp table name */

   u8 checkSchema;      /* Causes schema cookie check after an error */

   u8 nested;           /* Number of nested calls to the parser/code generator */

   u8 parseError;       /* True after a parsing error.  Ticket #1794 */

   u8 nTempReg;         /* Number of temporary registers in aTempReg[] */

   u8 nTempInUse;       /* Number of aTempReg[] currently checked out */

   int aTempReg[8];     /* Holding area for temporary registers */

   int nRangeReg;       /* Size of the temporary register block */

   int iRangeReg;       /* First register in temporary register block */

   int nErr;            /* Number of errors seen */

   int nTab;            /* Number of previously allocated VDBE cursors */

   int nMem;            /* Number of memory cells used so far */

   int nSet;            /* Number of sets used so far */

   int ckBase;          /* Base register of data during check constraints */

   int disableColCache; /* True to disable adding to column cache */

   int nColCache;       /* Number of entries in the column cache */

   int iColCache;       /* Next entry of the cache to replace */

   struct yColCache {

     int iTable;           /* Table cursor number */

     int iColumn;          /* Table column number */

     char affChange;       /* True if this register has had an affinity change */

     int iReg;             /* Register holding value of this column */

   } aColCache[10];     /* One for each valid column cache entry */

   u32 writeMask;       /* Start a write transaction on these databases */

   u32 cookieMask;      /* Bitmask of schema verified databases */

   int cookieGoto;      /* Address of OP_Goto to cookie verifier subroutine */

   int cookieValue[SQLITE_MAX_ATTACHED+2];  /* Values of cookies to verify */

 #ifndef SQLITE_OMIT_SHARED_CACHE

   int nTableLock;        /* Number of locks in aTableLock */

   TableLock *aTableLock; /* Required table locks for shared-cache mode */

 #endif

   int regRowid;        /* Register holding rowid of CREATE TABLE entry */

   int regRoot;         /* Register holding root page number for new objects */

   /* Above is constant between recursions.  Below is reset before and after

   ** each recursion */

   int nVar;            /* Number of '?' variables seen in the SQL so far */

   int nVarExpr;        /* Number of used slots in apVarExpr[] */

   int nVarExprAlloc;   /* Number of allocated slots in apVarExpr[] */

   Expr **apVarExpr;    /* Pointers to :aaa and $aaaa wildcard expressions */

   int nAlias;          /* Number of aliased result set columns */

   int nAliasAlloc;     /* Number of allocated slots for aAlias[] */

   int *aAlias;         /* Register used to hold aliased result */

   u8 explain;          /* True if the EXPLAIN flag is found on the query */

   Token sErrToken;     /* The token at which the error occurred */

   Token sNameToken;    /* Token with unqualified schema object name */

   Token sLastToken;    /* The last token parsed */

   const char *zSql;    /* All SQL text */

   const char *zTail;   /* All SQL text past the last semicolon parsed */

   Table *pNewTable;    /* A table being constructed by CREATE TABLE */

   Trigger *pNewTrigger;     /* Trigger under construct by a CREATE TRIGGER */

   TriggerStack *trigStack;  /* Trigger actions being coded */

   const char *zAuthContext; /* The 6th parameter to db->xAuth callbacks */

 #ifndef SQLITE_OMIT_VIRTUALTABLE

   Token sArg;                /* Complete text of a module argument */

   u8 declareVtab;            /* True if inside sqlite3_declare_vtab() */

   int nVtabLock;             /* Number of virtual tables to lock */

   Table **apVtabLock;        /* Pointer to virtual tables needing locking */

 #endif

   int nHeight;            /* Expression tree height of current sub-select */

   Table *pZombieTab;      /* List of Table objects to delete after code gen */

 };

 #ifdef SQLITE_OMIT_VIRTUALTABLE

   #define IN_DECLARE_VTAB 0

 #else

   #define IN_DECLARE_VTAB (pParse->declareVtab)

 #endif

 /*

 ** An instance of the following structure can be declared on a stack and used

 ** to save the Parse.zAuthContext value so that it can be restored later.

 */

 struct AuthContext {

   const char *zAuthContext;   /* Put saved Parse.zAuthContext here */

   Parse *pParse;              /* The Parse structure */

 };

 /*

 ** Bitfield flags for P2 value in OP_Insert and OP_Delete

 */

 #define OPFLAG_NCHANGE   1    /* Set to update db->nChange */

 #define OPFLAG_LASTROWID 2    /* Set to update db->lastRowid */

 #define OPFLAG_ISUPDATE  4    /* This OP_Insert is an sql UPDATE */

 #define OPFLAG_APPEND    8    /* This is likely to be an append */

 /*

  * Each trigger present in the database schema is stored as an instance of

  * struct Trigger. 

  *

  * Pointers to instances of struct Trigger are stored in two ways.

  * 1. In the "trigHash" hash table (part of the sqlite3* that represents the 

  *    database). This allows Trigger structures to be retrieved by name.

  * 2. All triggers associated with a single table form a linked list, using the

  *    pNext member of struct Trigger. A pointer to the first element of the

  *    linked list is stored as the "pTrigger" member of the associated

  *    struct Table.

  *

  * The "step_list" member points to the first element of a linked list

  * containing the SQL statements specified as the trigger program.

  */

 struct Trigger {

   char *name;             /* The name of the trigger                        */

   char *table;            /* The table or view to which the trigger applies */

   u8 op;                  /* One of TK_DELETE, TK_UPDATE, TK_INSERT         */

   u8 tr_tm;               /* One of TRIGGER_BEFORE, TRIGGER_AFTER */

   Expr *pWhen;            /* The WHEN clause of the expresion (may be NULL) */

   IdList *pColumns;       /* If this is an UPDATE OF <column-list> trigger,

                              the <column-list> is stored here */

   Token nameToken;        /* Token containing zName. Use during parsing only */

   Schema *pSchema;        /* Schema containing the trigger */

   Schema *pTabSchema;     /* Schema containing the table */

   TriggerStep *step_list; /* Link list of trigger program steps             */

   Trigger *pNext;         /* Next trigger associated with the table */

 };

 /*

 ** A trigger is either a BEFORE or an AFTER trigger.  The following constants

 ** determine which. 

 **

 ** If there are multiple triggers, you might of some BEFORE and some AFTER.

 ** In that cases, the constants below can be ORed together.

 */

 #define TRIGGER_BEFORE  1

 #define TRIGGER_AFTER   2

 /*

  * An instance of struct TriggerStep is used to store a single SQL statement

  * that is a part of a trigger-program. 

  *

  * Instances of struct TriggerStep are stored in a singly linked list (linked

  * using the "pNext" member) referenced by the "step_list" member of the 

  * associated struct Trigger instance. The first element of the linked list is

  * the first step of the trigger-program.

  * 

  * The "op" member indicates whether this is a "DELETE", "INSERT", "UPDATE" or

  * "SELECT" statement. The meanings of the other members is determined by the 

  * value of "op" as follows:

  *

  * (op == TK_INSERT)

  * orconf    -> stores the ON CONFLICT algorithm

  * pSelect   -> If this is an INSERT INTO ... SELECT ... statement, then

  *              this stores a pointer to the SELECT statement. Otherwise NULL.

  * target    -> A token holding the name of the table to insert into.

  * pExprList -> If this is an INSERT INTO ... VALUES ... statement, then

  *              this stores values to be inserted. Otherwise NULL.

  * pIdList   -> If this is an INSERT INTO ... (<column-names>) VALUES ... 

  *              statement, then this stores the column-names to be

  *              inserted into.

  *

  * (op == TK_DELETE)

  * target    -> A token holding the name of the table to delete from.

  * pWhere    -> The WHERE clause of the DELETE statement if one is specified.

  *              Otherwise NULL.

  * 

  * (op == TK_UPDATE)

  * target    -> A token holding the name of the table to update rows of.

  * pWhere    -> The WHERE clause of the UPDATE statement if one is specified.

  *              Otherwise NULL.

  * pExprList -> A list of the columns to update and the expressions to update

  *              them to. See sqlite3Update() documentation of "pChanges"

  *              argument.

  * 

  */

 struct TriggerStep {

   int op;              /* One of TK_DELETE, TK_UPDATE, TK_INSERT, TK_SELECT */

   int orconf;          /* OE_Rollback etc. */

   Trigger *pTrig;      /* The trigger that this step is a part of */

   Select *pSelect;     /* Valid for SELECT and sometimes 

                           INSERT steps (when pExprList == 0) */

   Token target;        /* Valid for DELETE, UPDATE, INSERT steps */

   Expr *pWhere;        /* Valid for DELETE, UPDATE steps */

   ExprList *pExprList; /* Valid for UPDATE statements and sometimes 

                            INSERT steps (when pSelect == 0)         */

   IdList *pIdList;     /* Valid for INSERT statements only */

   TriggerStep *pNext;  /* Next in the link-list */

   TriggerStep *pLast;  /* Last element in link-list. Valid for 1st elem only */

 };

 /*

  * An instance of struct TriggerStack stores information required during code

  * generation of a single trigger program. While the trigger program is being

  * coded, its associated TriggerStack instance is pointed to by the

  * "pTriggerStack" member of the Parse structure.

  *

  * The pTab member points to the table that triggers are being coded on. The 

  * newIdx member contains the index of the vdbe cursor that points at the temp

  * table that stores the new.* references. If new.* references are not valid

  * for the trigger being coded (for example an ON DELETE trigger), then newIdx

  * is set to -1. The oldIdx member is analogous to newIdx, for old.* references.

  *

  * The ON CONFLICT policy to be used for the trigger program steps is stored 

  * as the orconf member. If this is OE_Default, then the ON CONFLICT clause 

  * specified for individual triggers steps is used.

  *

  * struct TriggerStack has a "pNext" member, to allow linked lists to be

  * constructed. When coding nested triggers (triggers fired by other triggers)

  * each nested trigger stores its parent trigger's TriggerStack as the "pNext" 

  * pointer. Once the nested trigger has been coded, the pNext value is restored

  * to the pTriggerStack member of the Parse stucture and coding of the parent

  * trigger continues.

  *

  * Before a nested trigger is coded, the linked list pointed to by the 

  * pTriggerStack is scanned to ensure that the trigger is not about to be coded

  * recursively. If this condition is detected, the nested trigger is not coded.

  */

 struct TriggerStack {

   Table *pTab;         /* Table that triggers are currently being coded on */

   int newIdx;          /* Index of vdbe cursor to "new" temp table */

   int oldIdx;          /* Index of vdbe cursor to "old" temp table */

   u32 newColMask;

   u32 oldColMask;

   int orconf;          /* Current orconf policy */

   int ignoreJump;      /* where to jump to for a RAISE(IGNORE) */

   Trigger *pTrigger;   /* The trigger currently being coded */

   TriggerStack *pNext; /* Next trigger down on the trigger stack */

 };

 /*

 ** The following structure contains information used by the sqliteFix...

 ** routines as they walk the parse tree to make database references

 ** explicit.  

 */

 typedef struct DbFixer DbFixer;

 struct DbFixer {

   Parse *pParse;      /* The parsing context.  Error messages written here */

   const char *zDb;    /* Make sure all objects are contained in this database */

   const char *zType;  /* Type of the container - used for error messages */

   const Token *pName; /* Name of the container - used for error messages */

 };

 /*

 ** An objected used to accumulate the text of a string where we

 ** do not necessarily know how big the string will be in the end.

 */

 struct StrAccum {

   sqlite3 *db;         /* Optional database for lookaside.  Can be NULL */

   char *zBase;         /* A base allocation.  Not from malloc. */

   char *zText;         /* The string collected so far */

   int  nChar;          /* Length of the string so far */

   int  nAlloc;         /* Amount of space allocated in zText */

   int  mxAlloc;        /* Maximum allowed string length */

   u8   mallocFailed;   /* Becomes true if any memory allocation fails */

   u8   useMalloc;      /* True if zText is enlargable using realloc */

   u8   tooBig;         /* Becomes true if string size exceeds limits */

 };

 /*

 ** A pointer to this structure is used to communicate information

 ** from sqlite3Init and OP_ParseSchema into the sqlite3InitCallback.

 */

 typedef struct {

   sqlite3 *db;        /* The database being initialized */

   int iDb;            /* 0 for main database.  1 for TEMP, 2.. for ATTACHed */

   char **pzErrMsg;    /* Error message stored here */

   int rc;             /* Result code stored here */

 } InitData;

 /*

 ** Structure containing global configuration data for the SQLite library.

 **

 ** This structure also contains some state information.

 */

 struct Sqlite3Config {

   int bMemstat;                     /* True to enable memory status */

   int bCoreMutex;                   /* True to enable core mutexing */

   int bFullMutex;                   /* True to enable full mutexing */

   int mxStrlen;                     /* Maximum string length */

   int szLookaside;                  /* Default lookaside buffer size */

   int nLookaside;                   /* Default lookaside buffer count */

   sqlite3_mem_methods m;            /* Low-level memory allocation interface */

   sqlite3_mutex_methods mutex;      /* Low-level mutex interface */

   void *pHeap;                      /* Heap storage space */

   int nHeap;                        /* Size of pHeap[] */

   int mnReq, mxReq;                 /* Min and max heap requests sizes */

   void *pScratch;                   /* Scratch memory */

   int szScratch;                    /* Size of each scratch buffer */

   int nScratch;                     /* Number of scratch buffers */

   void *pPage;                      /* Page cache memory */

   int szPage;                       /* Size of each page in pPage[] */

   int nPage;                        /* Number of pages in pPage[] */

   int isInit;                       /* True after initialization has finished */

   int inProgress;                   /* True while initialization in progress */

   int isMallocInit;                 /* True after malloc is initialized */

   sqlite3_mutex *pInitMutex;        /* Mutex used by sqlite3_initialize() */

   int nRefInitMutex;                /* Number of users of pInitMutex */

   int nSmall;                       /* alloc size threshold used by mem6.c */

   int mxParserStack;                /* maximum depth of the parser stack */

   int sharedCacheEnabled;           /* true if shared-cache mode enabled */

 };

 /*

 ** Context pointer passed down through the tree-walk.

 */

 struct Walker {

   int (*xExprCallback)(Walker*, Expr*);     /* Callback for expressions */

   int (*xSelectCallback)(Walker*,Select*);  /* Callback for SELECTs */

   Parse *pParse;                            /* Parser context.  */

   union {                                   /* Extra data for callback */

     NameContext *pNC;                          /* Naming context */

     int i;                                     /* Integer value */

   } u;

 };

 /* Forward declarations */

 int sqlite3WalkExpr(Walker*, Expr*);

 int sqlite3WalkExprList(Walker*, ExprList*);

 int sqlite3WalkSelect(Walker*, Select*);

 int sqlite3WalkSelectExpr(Walker*, Select*);

 int sqlite3WalkSelectFrom(Walker*, Select*);

 /*

 ** Return code from the parse-tree walking primitives and their

 ** callbacks.

 */

 #define WRC_Continue    0

 #define WRC_Prune       1

 #define WRC_Abort       2

 /*

 ** Assuming zIn points to the first byte of a UTF-8 character,

 ** advance zIn to point to the first byte of the next UTF-8 character.

 */

 #define SQLITE_SKIP_UTF8(zIn) {                        \

   if( (*(zIn++))>=0xc0 ){                              \

     while( (*zIn & 0xc0)==0x80 ){ zIn++; }             \

   }                                                    \

 }

 /*

 ** The SQLITE_CORRUPT_BKPT macro can be either a constant (for production

 ** builds) or a function call (for debugging).  If it is a function call,

 ** it allows the operator to set a breakpoint at the spot where database

 ** corruption is first detected.

 */

 #ifdef SQLITE_DEBUG

   int sqlite3Corrupt(void);

 # define SQLITE_CORRUPT_BKPT sqlite3Corrupt()

 #else

 # define SQLITE_CORRUPT_BKPT SQLITE_CORRUPT

 #endif

 /*

 ** Internal function prototypes

 */

 int sqlite3StrICmp(const char *, const char *);

 int sqlite3StrNICmp(const char *, const char *, int);

 int sqlite3IsNumber(const char*, int*, u8);

 int sqlite3Strlen(sqlite3*, const char*);

 int sqlite3MallocInit(void);

 void sqlite3MallocEnd(void);

 void *sqlite3Malloc(int);

 void *sqlite3MallocZero(int);

 void *sqlite3DbMallocZero(sqlite3*, int);

 void *sqlite3DbMallocRaw(sqlite3*, int);

 char *sqlite3DbStrDup(sqlite3*,const char*);

 char *sqlite3DbStrNDup(sqlite3*,const char*, int);

 void *sqlite3Realloc(void*, int);

 void *sqlite3DbReallocOrFree(sqlite3 *, void *, int);

 void *sqlite3DbRealloc(sqlite3 *, void *, int);

 void sqlite3DbFree(sqlite3*, void*);

 int sqlite3MallocSize(void*);

 int sqlite3DbMallocSize(sqlite3*, void*);

 void *sqlite3ScratchMalloc(int);

 void sqlite3ScratchFree(void*);

 void *sqlite3PageMalloc(int);

 void sqlite3PageFree(void*);

 void sqlite3MemSetDefault(void);

 const sqlite3_mem_methods *sqlite3MemGetDefault(void);

 const sqlite3_mem_methods *sqlite3MemGetMemsys5(void);

 const sqlite3_mem_methods *sqlite3MemGetMemsys3(void);

 const sqlite3_mem_methods *sqlite3MemGetMemsys6(void);

 void sqlite3BenignMallocHooks(void (*)(void), void (*)(void));

 int sqlite3MemoryAlarm(void (*)(void*, sqlite3_int64, int), void*, sqlite3_int64);

 #ifndef SQLITE_MUTEX_OMIT

   sqlite3_mutex_methods *sqlite3DefaultMutex(void);

   sqlite3_mutex *sqlite3MutexAlloc(int);

   int sqlite3MutexInit(void);

   int sqlite3MutexEnd(void);

 #endif

 int sqlite3StatusValue(int);

 void sqlite3StatusAdd(int, int);

 void sqlite3StatusSet(int, int);

 int sqlite3IsNaN(double);

 void sqlite3VXPrintf(StrAccum*, int, const char*, va_list);

 char *sqlite3MPrintf(sqlite3*,const char*, ...);

 char *sqlite3VMPrintf(sqlite3*,const char*, va_list);

 char *sqlite3MAppendf(sqlite3*,char*,const char*,...);

 #if defined(SQLITE_TEST) || defined(SQLITE_DEBUG)

   void sqlite3DebugPrintf(const char*, ...);

 #endif

 #if defined(SQLITE_TEST)

   void *sqlite3TestTextToPtr(const char*);

 #endif

 void sqlite3SetString(char **, sqlite3*, const char*, ...);

 void sqlite3ErrorMsg(Parse*, const char*, ...);

 void sqlite3ErrorClear(Parse*);

 void sqlite3Dequote(char*);

 void sqlite3DequoteExpr(sqlite3*, Expr*);

 int sqlite3KeywordCode(const unsigned char*, int);

 int sqlite3RunParser(Parse*, const char*, char **);

 void sqlite3FinishCoding(Parse*);

 int sqlite3GetTempReg(Parse*);

 void sqlite3ReleaseTempReg(Parse*,int);

 int sqlite3GetTempRange(Parse*,int);

 void sqlite3ReleaseTempRange(Parse*,int,int);

 Expr *sqlite3Expr(sqlite3*, int, Expr*, Expr*, const Token*);

 Expr *sqlite3PExpr(Parse*, int, Expr*, Expr*, const Token*);

 Expr *sqlite3RegisterExpr(Parse*,Token*);

 Expr *sqlite3ExprAnd(sqlite3*,Expr*, Expr*);

 void sqlite3ExprSpan(Expr*,Token*,Token*);

 Expr *sqlite3ExprFunction(Parse*,ExprList*, Token*);

 void sqlite3ExprAssignVarNumber(Parse*, Expr*);

 void sqlite3ExprClear(sqlite3*, Expr*);

 void sqlite3ExprDelete(sqlite3*, Expr*);

 ExprList *sqlite3ExprListAppend(Parse*,ExprList*,Expr*,Token*);

 void sqlite3ExprListDelete(sqlite3*, ExprList*);

 int sqlite3Init(sqlite3*, char**);

 int sqlite3InitCallback(void*, int, char**, char**);

 void sqlite3Pragma(Parse*,Token*,Token*,Token*,int);

 void sqlite3ResetInternalSchema(sqlite3*, int);

 void sqlite3BeginParse(Parse*,int);

 void sqlite3CommitInternalChanges(sqlite3*);

 Table *sqlite3ResultSetOfSelect(Parse*,Select*);

 void sqlite3OpenMasterTable(Parse *, int);

 void sqlite3StartTable(Parse*,Token*,Token*,int,int,int,int);

 void sqlite3AddColumn(Parse*,Token*);

 void sqlite3AddNotNull(Parse*, int);

 void sqlite3AddPrimaryKey(Parse*, ExprList*, int, int, int);

 void sqlite3AddCheckConstraint(Parse*, Expr*);

 void sqlite3AddColumnType(Parse*,Token*);

 void sqlite3AddDefaultValue(Parse*,Expr*);

 void sqlite3AddCollateType(Parse*, Token*);

 void sqlite3EndTable(Parse*,Token*,Token*,Select*);

 Bitvec *sqlite3BitvecCreate(u32);

 int sqlite3BitvecTest(Bitvec*, u32);

 int sqlite3BitvecSet(Bitvec*, u32);

 void sqlite3BitvecClear(Bitvec*, u32);

 void sqlite3BitvecDestroy(Bitvec*);

 int sqlite3BitvecBuiltinTest(int,int*);

 void sqlite3CreateView(Parse*,Token*,Token*,Token*,Select*,int,int);

 #if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_VIRTUALTABLE)

   int sqlite3ViewGetColumnNames(Parse*,Table*);

 #else

 # define sqlite3ViewGetColumnNames(A,B) 0

 #endif

 void sqlite3DropTable(Parse*, SrcList*, int, int);

 void sqlite3DeleteTable(Table*);

 void sqlite3Insert(Parse*, SrcList*, ExprList*, Select*, IdList*, int);

 void *sqlite3ArrayAllocate(sqlite3*,void*,int,int,int*,int*,int*);

 IdList *sqlite3IdListAppend(sqlite3*, IdList*, Token*);

 int sqlite3IdListIndex(IdList*,const char*);

 SrcList *sqlite3SrcListAppend(sqlite3*, SrcList*, Token*, Token*);

 SrcList *sqlite3SrcListAppendFromTerm(Parse*, SrcList*, Token*, Token*,

                                       Token*, Select*, Expr*, IdList*);

 void sqlite3SrcListIndexedBy(Parse *, SrcList *, Token *);

 int sqlite3IndexedByLookup(Parse *, struct SrcList_item *);

 void sqlite3SrcListShiftJoinType(SrcList*);

 void sqlite3SrcListAssignCursors(Parse*, SrcList*);

 void sqlite3IdListDelete(sqlite3*, IdList*);

 void sqlite3SrcListDelete(sqlite3*, SrcList*);

 void sqlite3CreateIndex(Parse*,Token*,Token*,SrcList*,ExprList*,int,Token*,

                         Token*, int, int);

 void sqlite3DropIndex(Parse*, SrcList*, int);

 int sqlite3Select(Parse*, Select*, SelectDest*);

 Select *sqlite3SelectNew(Parse*,ExprList*,SrcList*,Expr*,ExprList*,

                          Expr*,ExprList*,int,Expr*,Expr*);

 void sqlite3SelectDelete(sqlite3*, Select*);

 Table *sqlite3SrcListLookup(Parse*, SrcList*);

 int sqlite3IsReadOnly(Parse*, Table*, int);

 void sqlite3OpenTable(Parse*, int iCur, int iDb, Table*, int);

 #if defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT) && !defined(SQLITE_OMIT_SUBQUERY)

 Expr *sqlite3LimitWhere(Parse *, SrcList *, Expr *, ExprList *, Expr *, Expr *, char *);

 #endif

 void sqlite3DeleteFrom(Parse*, SrcList*, Expr*);

 void sqlite3Update(Parse*, SrcList*, ExprList*, Expr*, int);

 WhereInfo *sqlite3WhereBegin(Parse*, SrcList*, Expr*, ExprList**, u8);

 void sqlite3WhereEnd(WhereInfo*);

 int sqlite3ExprCodeGetColumn(Parse*, Table*, int, int, int, int);

 void sqlite3ExprCodeMove(Parse*, int, int, int);

 void sqlite3ExprCodeCopy(Parse*, int, int, int);

 void sqlite3ExprClearColumnCache(Parse*, int);

 void sqlite3ExprCacheAffinityChange(Parse*, int, int);

 int sqlite3ExprWritableRegister(Parse*,int,int);

 void sqlite3ExprHardCopy(Parse*,int,int);

 int sqlite3ExprCode(Parse*, Expr*, int);

 int sqlite3ExprCodeTemp(Parse*, Expr*, int*);

 int sqlite3ExprCodeTarget(Parse*, Expr*, int);

 int sqlite3ExprCodeAndCache(Parse*, Expr*, int);

 void sqlite3ExprCodeConstants(Parse*, Expr*);

 int sqlite3ExprCodeExprList(Parse*, ExprList*, int, int);

 void sqlite3ExprIfTrue(Parse*, Expr*, int, int);

 void sqlite3ExprIfFalse(Parse*, Expr*, int, int);

 Table *sqlite3FindTable(sqlite3*,const char*, const char*);

 Table *sqlite3LocateTable(Parse*,int isView,const char*, const char*);

 Index *sqlite3FindIndex(sqlite3*,const char*, const char*);

 void sqlite3UnlinkAndDeleteTable(sqlite3*,int,const char*);

 void sqlite3UnlinkAndDeleteIndex(sqlite3*,int,const char*);

 void sqlite3Vacuum(Parse*);

 int sqlite3RunVacuum(char**, sqlite3*);

 char *sqlite3NameFromToken(sqlite3*, Token*);

 int sqlite3ExprCompare(Expr*, Expr*);

 void sqlite3ExprAnalyzeAggregates(NameContext*, Expr*);

 void sqlite3ExprAnalyzeAggList(NameContext*,ExprList*);

 Vdbe *sqlite3GetVdbe(Parse*);

 Expr *sqlite3CreateIdExpr(Parse *, const char*);

 void sqlite3PrngSaveState(void);

 void sqlite3PrngRestoreState(void);

 void sqlite3PrngResetState(void);

 void sqlite3RollbackAll(sqlite3*);

 void sqlite3CodeVerifySchema(Parse*, int);

 void sqlite3BeginTransaction(Parse*, int);

 void sqlite3CommitTransaction(Parse*);

 void sqlite3RollbackTransaction(Parse*);

 int sqlite3ExprIsConstant(Expr*);

 int sqlite3ExprIsConstantNotJoin(Expr*);

 int sqlite3ExprIsConstantOrFunction(Expr*);

 int sqlite3ExprIsInteger(Expr*, int*);

 int sqlite3IsRowid(const char*);

 void sqlite3GenerateRowDelete(Parse*, Table*, int, int, int);

 void sqlite3GenerateRowIndexDelete(Parse*, Table*, int, int*);

 int sqlite3GenerateIndexKey(Parse*, Index*, int, int, int);

 void sqlite3GenerateConstraintChecks(Parse*,Table*,int,int,

                                      int*,int,int,int,int);

 void sqlite3CompleteInsertion(Parse*, Table*, int, int, int*,int,int,int,int);

 int sqlite3OpenTableAndIndices(Parse*, Table*, int, int);

 void sqlite3BeginWriteOperation(Parse*, int, int);

 Expr *sqlite3ExprDup(sqlite3*,Expr*);

 void sqlite3TokenCopy(sqlite3*,Token*, Token*);

 ExprList *sqlite3ExprListDup(sqlite3*,ExprList*);

 SrcList *sqlite3SrcListDup(sqlite3*,SrcList*);

 IdList *sqlite3IdListDup(sqlite3*,IdList*);

 Select *sqlite3SelectDup(sqlite3*,Select*);

 void sqlite3FuncDefInsert(FuncDefHash*, FuncDef*);

 FuncDef *sqlite3FindFunction(sqlite3*,const char*,int,int,u8,int);

 void sqlite3RegisterBuiltinFunctions(sqlite3*);

 void sqlite3RegisterDateTimeFunctions(void);

 void sqlite3RegisterGlobalFunctions(void);

 int sqlite3GetBuiltinFunction(const char *, int, FuncDef **);

 #ifdef SQLITE_DEBUG

   int sqlite3SafetyOn(sqlite3*);

   int sqlite3SafetyOff(sqlite3*);

 #else

 # define sqlite3SafetyOn(A) 0

 # define sqlite3SafetyOff(A) 0

 #endif

 int sqlite3SafetyCheckOk(sqlite3*);

 int sqlite3SafetyCheckSickOrOk(sqlite3*);

 void sqlite3ChangeCookie(Parse*, int);

 #if !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER)

 void sqlite3MaterializeView(Parse*, Table*, Expr*, int);

 #endif

 #ifndef SQLITE_OMIT_TRIGGER

   void sqlite3BeginTrigger(Parse*, Token*,Token*,int,int,IdList*,SrcList*,

                            Expr*,int, int);

   void sqlite3FinishTrigger(Parse*, TriggerStep*, Token*);

   void sqlite3DropTrigger(Parse*, SrcList*, int);

   void sqlite3DropTriggerPtr(Parse*, Trigger*);

   int sqlite3TriggersExist(Parse*, Table*, int, ExprList*);

   int sqlite3CodeRowTrigger(Parse*, int, ExprList*, int, Table *, int, int, 

                            int, int, u32*, u32*);

   void sqliteViewTriggers(Parse*, Table*, Expr*, int, ExprList*);

   void sqlite3DeleteTriggerStep(sqlite3*, TriggerStep*);

   TriggerStep *sqlite3TriggerSelectStep(sqlite3*,Select*);

   TriggerStep *sqlite3TriggerInsertStep(sqlite3*,Token*, IdList*,

                                         ExprList*,Select*,int);

   TriggerStep *sqlite3TriggerUpdateStep(sqlite3*,Token*,ExprList*, Expr*, int);

   TriggerStep *sqlite3TriggerDeleteStep(sqlite3*,Token*, Expr*);

   void sqlite3DeleteTrigger(sqlite3*, Trigger*);

   void sqlite3UnlinkAndDeleteTrigger(sqlite3*,int,const char*);

 #else

 # define sqlite3TriggersExist(A,B,C,D,E,F) 0

 # define sqlite3DeleteTrigger(A,B)

 # define sqlite3DropTriggerPtr(A,B)

 # define sqlite3UnlinkAndDeleteTrigger(A,B,C)

 # define sqlite3CodeRowTrigger(A,B,C,D,E,F,G,H,I,J,K) 0

 #endif

 int sqlite3JoinType(Parse*, Token*, Token*, Token*);

 void sqlite3CreateForeignKey(Parse*, ExprList*, Token*, ExprList*, int);

 void sqlite3DeferForeignKey(Parse*, int);

 #ifndef SQLITE_OMIT_AUTHORIZATION

   void sqlite3AuthRead(Parse*,Expr*,Schema*,SrcList*);

   int sqlite3AuthCheck(Parse*,int, const char*, const char*, const char*);

   void sqlite3AuthContextPush(Parse*, AuthContext*, const char*);

   void sqlite3AuthContextPop(AuthContext*);

 #else

 # define sqlite3AuthRead(a,b,c,d)

 # define sqlite3AuthCheck(a,b,c,d,e)    SQLITE_OK

 # define sqlite3AuthContextPush(a,b,c)

 # define sqlite3AuthContextPop(a)  ((void)(a))

 #endif

 void sqlite3Attach(Parse*, Expr*, Expr*, Expr*);

 void sqlite3Detach(Parse*, Expr*);

 int sqlite3BtreeFactory(const sqlite3 *db, const char *zFilename,

                        int omitJournal, int nCache, int flags, Btree **ppBtree);

 int sqlite3FixInit(DbFixer*, Parse*, int, const char*, const Token*);

 int sqlite3FixSrcList(DbFixer*, SrcList*);

 int sqlite3FixSelect(DbFixer*, Select*);

 int sqlite3FixExpr(DbFixer*, Expr*);

 int sqlite3FixExprList(DbFixer*, ExprList*);

 int sqlite3FixTriggerStep(DbFixer*, TriggerStep*);

 int sqlite3AtoF(const char *z, double*);

 int sqlite3GetInt32(const char *, int*);

 int sqlite3FitsIn64Bits(const char *, int);

 int sqlite3Utf16ByteLen(const void *pData, int nChar);

 int sqlite3Utf8CharLen(const char *pData, int nByte);

 int sqlite3Utf8Read(const u8*, const u8*, const u8**);

 /*

 ** Routines to read and write variable-length integers.  These used to

 ** be defined locally, but now we use the varint routines in the util.c

 ** file.  Code should use the MACRO forms below, as the Varint32 versions

 ** are coded to assume the single byte case is already handled (which 

 ** the MACRO form does).

 */

 int sqlite3PutVarint(unsigned char*, u64);

 int sqlite3PutVarint32(unsigned char*, u32);

 int sqlite3GetVarint(const unsigned char *, u64 *);

 int sqlite3GetVarint32(const unsigned char *, u32 *);

 int sqlite3VarintLen(u64 v);

 /*

 ** The header of a record consists of a sequence variable-length integers.

 ** These integers are almost always small and are encoded as a single byte.

 ** The following macros take advantage this fact to provide a fast encode

 ** and decode of the integers in a record header.  It is faster for the common

 ** case where the integer is a single byte.  It is a little slower when the

 ** integer is two or more bytes.  But overall it is faster.

 **

 ** The following expressions are equivalent:

 **

 **     x = sqlite3GetVarint32( A, &B );

 **     x = sqlite3PutVarint32( A, B );

 **

 **     x = getVarint32( A, B );

 **     x = putVarint32( A, B );

 **

 */

 #define getVarint32(A,B)  ((*(A)<(unsigned char)0x80) ? ((B) = (u32)*(A)),1 : sqlite3GetVarint32((A), &(B)))

 #define putVarint32(A,B)  (((B)<(u32)0x80) ? (*(A) = (unsigned char)(B)),1 : sqlite3PutVarint32((A), (B)))

 #define getVarint    sqlite3GetVarint

 #define putVarint    sqlite3PutVarint

 void sqlite3IndexAffinityStr(Vdbe *, Index *);

 void sqlite3TableAffinityStr(Vdbe *, Table *);

 char sqlite3CompareAffinity(Expr *pExpr, char aff2);

 int sqlite3IndexAffinityOk(Expr *pExpr, char idx_affinity);

 char sqlite3ExprAffinity(Expr *pExpr);

 int sqlite3Atoi64(const char*, i64*);

 void sqlite3Error(sqlite3*, int, const char*,...);

 void *sqlite3HexToBlob(sqlite3*, const char *z, int n);

 int sqlite3TwoPartName(Parse *, Token *, Token *, Token **);

 const char *sqlite3ErrStr(int);

 int sqlite3ReadSchema(Parse *pParse);

 CollSeq *sqlite3FindCollSeq(sqlite3*,u8 enc, const char *,int,int);

 CollSeq *sqlite3LocateCollSeq(Parse *pParse, const char *zName, int nName);

 CollSeq *sqlite3ExprCollSeq(Parse *pParse, Expr *pExpr);

 Expr *sqlite3ExprSetColl(Parse *pParse, Expr *, Token *);

 int sqlite3CheckCollSeq(Parse *, CollSeq *);

 int sqlite3CheckObjectName(Parse *, const char *);

 void sqlite3VdbeSetChanges(sqlite3 *, int);

 const void *sqlite3ValueText(sqlite3_value*, u8);

 int sqlite3ValueBytes(sqlite3_value*, u8);

 void sqlite3ValueSetStr(sqlite3_value*, int, const void *,u8, 

                         void(*)(void*));

 void sqlite3ValueFree(sqlite3_value*);

 sqlite3_value *sqlite3ValueNew(sqlite3 *);

 char *sqlite3Utf16to8(sqlite3 *, const void*, int);

 int sqlite3ValueFromExpr(sqlite3 *, Expr *, u8, u8, sqlite3_value **);

 void sqlite3ValueApplyAffinity(sqlite3_value *, u8, u8);

 #ifndef SQLITE_AMALGAMATION

 extern const unsigned char sqlite3UpperToLower[];

 extern SQLITE_WSD struct Sqlite3Config sqlite3Config;

 extern SQLITE_WSD FuncDefHash sqlite3GlobalFunctions;

 #endif

 void sqlite3RootPageMoved(Db*, int, int);

 void sqlite3Reindex(Parse*, Token*, Token*);

 void sqlite3AlterFunctions(sqlite3*);

 void sqlite3AlterRenameTable(Parse*, SrcList*, Token*);

 int sqlite3GetToken(const unsigned char *, int *);

 void sqlite3NestedParse(Parse*, const char*, ...);

 void sqlite3ExpirePreparedStatements(sqlite3*);

 void sqlite3CodeSubselect(Parse *, Expr *, int, int);

 void sqlite3SelectPrep(Parse*, Select*, NameContext*);

 int sqlite3ResolveExprNames(NameContext*, Expr*);

 void sqlite3ResolveSelectNames(Parse*, Select*, NameContext*);

 int sqlite3ResolveOrderGroupBy(Parse*, Select*, ExprList*, const char*);

 void sqlite3ColumnDefault(Vdbe *, Table *, int);

 void sqlite3AlterFinishAddColumn(Parse *, Token *);

 void sqlite3AlterBeginAddColumn(Parse *, SrcList *);

 CollSeq *sqlite3GetCollSeq(sqlite3*, CollSeq *, const char *, int);

 char sqlite3AffinityType(const Token*);

 void sqlite3Analyze(Parse*, Token*, Token*);

 int sqlite3InvokeBusyHandler(BusyHandler*);

 int sqlite3FindDb(sqlite3*, Token*);

 int sqlite3AnalysisLoad(sqlite3*,int iDB);

 void sqlite3DefaultRowEst(Index*);

 void sqlite3RegisterLikeFunctions(sqlite3*, int);

 int sqlite3IsLikeFunction(sqlite3*,Expr*,int*,char*);

 void sqlite3AttachFunctions(sqlite3 *);

 void sqlite3MinimumFileFormat(Parse*, int, int);

 void sqlite3SchemaFree(void *);

 Schema *sqlite3SchemaGet(sqlite3 *, Btree *);

 int sqlite3SchemaToIndex(sqlite3 *db, Schema *);

 KeyInfo *sqlite3IndexKeyinfo(Parse *, Index *);

 int sqlite3CreateFunc(sqlite3 *, const char *, int, int, void *, 

   void (*)(sqlite3_context*,int,sqlite3_value **),

   void (*)(sqlite3_context*,int,sqlite3_value **), void (*)(sqlite3_context*));

 int sqlite3ApiExit(sqlite3 *db, int);

 int sqlite3OpenTempDatabase(Parse *);

 void sqlite3StrAccumInit(StrAccum*, char*, int, int);

 void sqlite3StrAccumAppend(StrAccum*,const char*,int);

 char *sqlite3StrAccumFinish(StrAccum*);

 void sqlite3StrAccumReset(StrAccum*);

 void sqlite3SelectDestInit(SelectDest*,int,int);

 /*

 ** The interface to the LEMON-generated parser

 */

 void *sqlite3ParserAlloc(void*(*)(size_t));

 void sqlite3ParserFree(void*, void(*)(void*));

 void sqlite3Parser(void*, int, Token, Parse*);

 #ifdef YYTRACKMAXSTACKDEPTH

   int sqlite3ParserStackPeak(void*);

 #endif

 int sqlite3AutoLoadExtensions(sqlite3*);

 #ifndef SQLITE_OMIT_LOAD_EXTENSION

   void sqlite3CloseExtensions(sqlite3*);

 #else

 # define sqlite3CloseExtensions(X)

 #endif

 #ifndef SQLITE_OMIT_SHARED_CACHE

   void sqlite3TableLock(Parse *, int, int, u8, const char *);

 #else

   #define sqlite3TableLock(v,w,x,y,z)

 #endif

 #ifdef SQLITE_TEST

   int sqlite3Utf8To8(unsigned char*);

 #endif

 #ifdef SQLITE_OMIT_VIRTUALTABLE

 #  define sqlite3VtabClear(X)

 #  define sqlite3VtabSync(X,Y) SQLITE_OK

 #  define sqlite3VtabRollback(X)

 #  define sqlite3VtabCommit(X)

 #else

    void sqlite3VtabClear(Table*);

    int sqlite3VtabSync(sqlite3 *db, char **);

    int sqlite3VtabRollback(sqlite3 *db);

    int sqlite3VtabCommit(sqlite3 *db);

 #endif

 void sqlite3VtabMakeWritable(Parse*,Table*);

 void sqlite3VtabLock(sqlite3_vtab*);

 void sqlite3VtabUnlock(sqlite3*, sqlite3_vtab*);

 void sqlite3VtabBeginParse(Parse*, Token*, Token*, Token*);

 void sqlite3VtabFinishParse(Parse*, Token*);

 void sqlite3VtabArgInit(Parse*);

 void sqlite3VtabArgExtend(Parse*, Token*);

 int sqlite3VtabCallCreate(sqlite3*, int, const char *, char **);

 int sqlite3VtabCallConnect(Parse*, Table*);

 int sqlite3VtabCallDestroy(sqlite3*, int, const char *);

 int sqlite3VtabBegin(sqlite3 *, sqlite3_vtab *);

 FuncDef *sqlite3VtabOverloadFunction(sqlite3 *,FuncDef*, int nArg, Expr*);

 void sqlite3InvalidFunction(sqlite3_context*,int,sqlite3_value**);

 int sqlite3TransferBindings(sqlite3_stmt *, sqlite3_stmt *);

 int sqlite3Reprepare(Vdbe*);

 void sqlite3ExprListCheckLength(Parse*, ExprList*, const char*);

 CollSeq *sqlite3BinaryCompareCollSeq(Parse *, Expr *, Expr *);

 /*

 ** Available fault injectors.  Should be numbered beginning with 0.

 */

 #define SQLITE_FAULTINJECTOR_MALLOC     0

 #define SQLITE_FAULTINJECTOR_COUNT      1

 /*

 ** The interface to the code in fault.c used for identifying "benign"

 ** malloc failures. This is only present if SQLITE_OMIT_BUILTIN_TEST

 ** is not defined.

 */

 #ifndef SQLITE_OMIT_BUILTIN_TEST

   void sqlite3BeginBenignMalloc(void);

   void sqlite3EndBenignMalloc(void);

 #else

   #define sqlite3BeginBenignMalloc()

   #define sqlite3EndBenignMalloc()

 #endif

 #define IN_INDEX_ROWID           1

 #define IN_INDEX_EPH             2

 #define IN_INDEX_INDEX           3

 int sqlite3FindInIndex(Parse *, Expr *, int*);

 #ifdef SQLITE_ENABLE_ATOMIC_WRITE

   int sqlite3JournalOpen(sqlite3_vfs *, const char *, sqlite3_file *, int, int);

   int sqlite3JournalSize(sqlite3_vfs *);

   int sqlite3JournalCreate(sqlite3_file *);

 #else

   #define sqlite3JournalSize(pVfs) ((pVfs)->szOsFile)

 #endif

 #if SQLITE_MAX_EXPR_DEPTH>0

   void sqlite3ExprSetHeight(Parse *pParse, Expr *p);

   int sqlite3SelectExprHeight(Select *);

   int sqlite3ExprCheckHeight(Parse*, int);

 #else

   #define sqlite3ExprSetHeight(x,y)

   #define sqlite3SelectExprHeight(x) 0

   #define sqlite3ExprCheckHeight(x,y)

 #endif

 u32 sqlite3Get4byte(const u8*);

 void sqlite3Put4byte(u8*, u32);

 #ifdef SQLITE_SSE

 #include "sseInt.h"

 #endif

 #ifdef SQLITE_DEBUG

   void sqlite3ParserTrace(FILE*, char *);

 #endif

 /*

 ** If the SQLITE_ENABLE IOTRACE exists then the global variable

 ** sqlite3IoTrace is a pointer to a printf-like routine used to

 ** print I/O tracing messages. 

 */

 #ifdef SQLITE_ENABLE_IOTRACE

 # define IOTRACE(A)  if( sqlite3IoTrace ){ sqlite3IoTrace A; }

   void sqlite3VdbeIOTraceSql(Vdbe*);

 SQLITE_EXTERN void (*sqlite3IoTrace)(const char*,...);

 #else

 # define IOTRACE(A)

 # define sqlite3VdbeIOTraceSql(X)

 #endif

 #endif