/*** 2003 September 6**** The author disclaims copyright to this source code.  In place of** a legal notice, here is a blessing:****    May you do good and not evil.**    May you find forgiveness for yourself and forgive others.**    May you share freely, never taking more than you give.***************************************************************************** This is the header file for information that is private to the** VDBE.  This information used to all be at the top of the single** source code file "vdbe.c".  When that file became too big (over** 6000 lines long) it was split up into several smaller files and** this header information was factored out.*//*** intToKey() and keyToInt() used to transform the rowid.  But with** the latest versions of the design they are no-ops.*/#define keyToInt(X)   (X)#define intToKey(X)   (X)/*** The makefile scans the vdbe.c source file and creates the following** array of string constants which are the names of all VDBE opcodes.  This** array is defined in a separate source code file named opcode.c which is** automatically generated by the makefile.*/extern char *sqlite3OpcodeNames[];/*** SQL is translated into a sequence of instructions to be** executed by a virtual machine.  Each instruction is an instance** of the following structure.*/typedef struct VdbeOp Op;/*** Boolean values*/typedef unsigned char Bool;/*** A cursor is a pointer into a single BTree within a database file.** The cursor can seek to a BTree entry with a particular key, or** loop over all entries of the Btree.  You can also insert new BTree** entries or retrieve the key or data from the entry that the cursor** is currently pointing to.** ** Every cursor that the virtual machine has open is represented by an** instance of the following structure.**** If the Cursor.isTriggerRow flag is set it means that this cursor is** really a single row that represents the NEW or OLD pseudo-table of** a row trigger.  The data for the row is stored in Cursor.pData and** the rowid is in Cursor.iKey.*/struct Cursor {  BtCursor *pCursor;    /* The cursor structure of the backend */  int iDb;              /* Index of cursor database in db->aDb[] (or -1) */  i64 lastRowid;        /* Last rowid from a Next or NextIdx operation */  i64 nextRowid;        /* Next rowid returned by OP_NewRowid */  Bool zeroed;          /* True if zeroed out and ready for reuse */  Bool rowidIsValid;    /* True if lastRowid is valid */  Bool atFirst;         /* True if pointing to first entry */  Bool useRandomRowid;  /* Generate new record numbers semi-randomly */  Bool nullRow;         /* True if pointing to a row with no data */  Bool nextRowidValid;  /* True if the nextRowid field is valid */  Bool pseudoTable;     /* This is a NEW or OLD pseudo-tables of a trigger */  Bool deferredMoveto;  /* A call to sqlite3BtreeMoveto() is needed */  Bool isTable;         /* True if a table requiring integer keys */  Bool isIndex;         /* True if an index containing keys only - no data */  u8 bogusIncrKey;      /* Something for pIncrKey to point to if pKeyInfo==0 */  i64 movetoTarget;     /* Argument to the deferred sqlite3BtreeMoveto() */  Btree *pBt;           /* Separate file holding temporary table */  int nData;            /* Number of bytes in pData */  char *pData;          /* Data for a NEW or OLD pseudo-table */  i64 iKey;             /* Key for the NEW or OLD pseudo-table row */  u8 *pIncrKey;         /* Pointer to pKeyInfo->incrKey */  KeyInfo *pKeyInfo;    /* Info about index keys needed by index cursors */  int nField;           /* Number of fields in the header */  i64 seqCount;         /* Sequence counter */  /* Cached information about the header for the data record that the  ** cursor is currently pointing to.  Only valid if cacheValid is true.  ** aRow might point to (ephemeral) data for the current row, or it might  ** be NULL.  */  int cacheStatus;      /* Cache is valid if this matches Vdbe.cacheCtr */  int payloadSize;      /* Total number of bytes in the record */  u32 *aType;           /* Type values for all entries in the record */  u32 *aOffset;         /* Cached offsets to the start of each columns data */  u8 *aRow;             /* Data for the current row, if all on one page */};typedef struct Cursor Cursor;/*** Number of bytes of string storage space available to each stack** layer without having to malloc.  NBFS is short for Number of Bytes** For Strings.*/#define NBFS 32/*** A value for Cursor.cacheValid that means the cache is always invalid.*/#define CACHE_STALE 0/*** Internally, the vdbe manipulates nearly all SQL values as Mem** structures. Each Mem struct may cache multiple representations (string,** integer etc.) of the same value.  A value (and therefore Mem structure)** has the following properties:**** Each value has a manifest type. The manifest type of the value stored** in a Mem struct is returned by the MemType(Mem*) macro. The type is** one of SQLITE_NULL, SQLITE_INTEGER, SQLITE_REAL, SQLITE_TEXT or** SQLITE_BLOB.*/struct Mem {  i64 i;              /* Integer value. Or FuncDef* when flags==MEM_Agg */  double r;           /* Real value */  char *z;            /* String or BLOB value */  int n;              /* Number of characters in string value, including '\0' */  u16 flags;          /* Some combination of MEM_Null, MEM_Str, MEM_Dyn, etc. */  u8  type;           /* One of MEM_Null, MEM_Str, etc. */  u8  enc;            /* TEXT_Utf8, TEXT_Utf16le, or TEXT_Utf16be */  void (*xDel)(void *);  /* If not null, call this function to delete Mem.z */  char zShort[NBFS];  /* Space for short strings */};typedef struct Mem Mem;/* One or more of the following flags are set to indicate the validOK** representations of the value stored in the Mem struct.**** If the MEM_Null flag is set, then the value is an SQL NULL value.** No other flags may be set in this case.**** If the MEM_Str flag is set then Mem.z points at a string representation.** Usually this is encoded in the same unicode encoding as the main** database (see below for exceptions). If the MEM_Term flag is also** set, then the string is nul terminated. The MEM_Int and MEM_Real ** flags may coexist with the MEM_Str flag.**** Multiple of these values can appear in Mem.flags.  But only one** at a time can appear in Mem.type.*/#define MEM_Null      0x0001   /* Value is NULL */#define MEM_Str       0x0002   /* Value is a string */#define MEM_Int       0x0004   /* Value is an integer */#define MEM_Real      0x0008   /* Value is a real number */#define MEM_Blob      0x0010   /* Value is a BLOB *//* Whenever Mem contains a valid string or blob representation, one of** the following flags must be set to determine the memory management** policy for Mem.z.  The MEM_Term flag tells us whether or not the** string is \000 or \u0000 terminated*/#define MEM_Term      0x0020   /* String rep is nul terminated */#define MEM_Dyn       0x0040   /* Need to call sqliteFree() on Mem.z */#define MEM_Static    0x0080   /* Mem.z points to a static string */#define MEM_Ephem     0x0100   /* Mem.z points to an ephemeral string */#define MEM_Short     0x0200   /* Mem.z points to Mem.zShort */#define MEM_Agg       0x0400   /* Mem.z points to an agg function context *//* A VdbeFunc is just a FuncDef (defined in sqliteInt.h) that contains** additional information about auxiliary information bound to arguments** of the function.  This is used to implement the sqlite3_get_auxdata()** and sqlite3_set_auxdata() APIs.  The "auxdata" is some auxiliary data** that can be associated with a constant argument to a function.  This** allows functions such as "regexp" to compile their constant regular** expression argument once and reused the compiled code for multiple** invocations.*/struct VdbeFunc {  FuncDef *pFunc;               /* The definition of the function */  int nAux;                     /* Number of entries allocated for apAux[] */  struct AuxData {    void *pAux;                   /* Aux data for the i-th argument */    void (*xDelete)(void *);      /* Destructor for the aux data */  } apAux[1];                   /* One slot for each function argument */};typedef struct VdbeFunc VdbeFunc;/*** The "context" argument for a installable function.  A pointer to an** instance of this structure is the first argument to the routines used** implement the SQL functions.**** There is a typedef for this structure in sqlite.h.  So all routines,** even the public interface to SQLite, can use a pointer to this structure.** But this file is the only place where the internal details of this** structure are known.