/*** 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.*//*** When converting from the native format to the key format and back** again, in addition to changing the byte order we invert the high-order** bit of the most significant byte.  This causes negative numbers to** sort before positive numbers in the memcmp() function.*/#define keyToInt(X)   (sqliteVdbeByteSwap(X) ^ 0x80000000)#define intToKey(X)   (sqliteVdbeByteSwap((X) ^ 0x80000000))/*** The makefile scans this 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 *sqliteOpcodeNames[];/*** 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 lastRecno;        /* Last recno from a Next or NextIdx operation */  int nextRowid;        /* Next rowid returned by OP_NewRowid */  Bool recnoIsValid;    /* True if lastRecno is valid */  Bool keyAsData;       /* The OP_Column command works on key instead of data */  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 sqliteBtreeMoveto() is needed */  int movetoTarget;     /* Argument to the deferred sqliteBtreeMoveto() */  Btree *pBt;           /* Separate file holding temporary table */  int nData;            /* Number of bytes in pData */  char *pData;          /* Data for a NEW or OLD pseudo-table */  int iKey;             /* Key for the NEW or OLD pseudo-table row */};typedef struct Cursor Cursor;/*** A sorter builds a list of elements to be sorted.  Each element of** the list is an instance of the following structure.*/typedef struct Sorter Sorter;struct Sorter {  int nKey;           /* Number of bytes in the key */  char *zKey;         /* The key by which we will sort */  int nData;          /* Number of bytes in the data */  char *pData;        /* The data associated with this key */  Sorter *pNext;      /* Next in the list */};/* ** Number of buckets used for merge-sort.  */#define NSORT 30/*** 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 single level of the stack or a single memory cell** is an instance of the following structure. */struct Mem {  int i;              /* Integer value */  int n;              /* Number of characters in string value, including '\0' */  int flags;          /* Some combination of MEM_Null, MEM_Str, MEM_Dyn, etc. */  double r;           /* Real value */  char *z;            /* String value */  char zShort[NBFS];  /* Space for short strings */};typedef struct Mem Mem;/*** Allowed values for Mem.flags*/#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_Dyn       0x0010   /* Need to call sqliteFree() on Mem.z */#define MEM_Static    0x0020   /* Mem.z points to a static string */#define MEM_Ephem     0x0040   /* Mem.z points to an ephemeral string */#define MEM_Short     0x0080   /* Mem.z points to Mem.zShort *//* The following MEM_ value appears only in AggElem.aMem.s.flag fields.** It indicates that the corresponding AggElem.aMem.z points to a** aggregate function context that needs to be finalized.*/#define MEM_AggCtx    0x0100   /* Mem.z points to an agg function context *//*** 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.**** This structure is defined inside of vdbe.c because it uses substructures** (Mem) which are only defined there.*/struct sqlite_func {  FuncDef *pFunc;   /* Pointer to function information.  MUST BE FIRST */  Mem s;            /* The return value is stored here */  void *pAgg;       /* Aggregate context */  u8 isError;       /* Set to true for an error */  u8 isStep;        /* Current in the step function */  int cnt;          /* Number of times that the step function has been called */};/*** An Agg structure describes an Aggregator.  Each Agg consists of** zero or more Aggregator elements (AggElem).  Each AggElem contains** a key and one or more values.  The values are used in processing** aggregate functions in a SELECT.  The key is used to implement** the GROUP BY clause of a select.*/typedef struct Agg Agg;typedef struct AggElem AggElem;struct Agg {  int nMem;            /* Number of values stored in each AggElem */  AggElem *pCurrent;   /* The AggElem currently in focus */  HashElem *pSearch;   /* The hash element for pCurrent */  Hash hash;           /* Hash table of all aggregate elements */  FuncDef **apFunc;    /* Information about aggregate functions */};struct AggElem {  char *zKey;          /* The key to this AggElem */  int nKey;            /* Number of bytes in the key, including '\0' at end */  Mem aMem[1];         /* The values for this AggElem */};/*** A Set structure is used for quick testing to see if a value** is part of a small set.  Sets are used to implement code like** this:**            x.y IN ('hi','hoo','hum')*/typedef struct Set Set;struct Set {  Hash hash;             /* A set is just a hash table */  HashElem *prev;        /* Previously accessed hash elemen */};/*** A Keylist is a bunch of keys into a table.  The keylist can** grow without bound.  The keylist stores the ROWIDs of database** records that need to be deleted or updated.*/typedef struct Keylist Keylist;struct Keylist {  int nKey;         /* Number of slots in aKey[] */  int nUsed;        /* Next unwritten slot in aKey[] */  int nRead;        /* Next unread slot in aKey[] */  Keylist *pNext;   /* Next block of keys */  int aKey[1];      /* One or more keys.  Extra space allocated as needed */};/*** A Context stores the last insert rowid, the last statement change count,** and the current statement change count (i.e. changes since last statement).** Elements of Context structure type make up the ContextStack, which is** updated by the ContextPush and ContextPop opcodes (used by triggers)*/typedef struct Context Context;struct Context {  int lastRowid;    /* Last insert rowid (from db->lastRowid) */  int lsChange;     /* Last statement change count (from db->lsChange) */  int csChange;     /* Current statement change count (from db->csChange) */};/*** An instance of the virtual machine.  This structure contains the complete** state of the virtual machine.**** The "sqlite_vm" structure pointer that is returned by sqlite_compile()** is really a pointer to an instance of this structure.*/struct Vdbe {  sqlite *db;         /* The whole database */  Vdbe *pPrev,*pNext; /* Linked list of VDBEs with the same Vdbe.db */  FILE *trace;        /* Write an execution trace here, if not NULL */  int nOp;            /* Number of instructions in the program */  int nOpAlloc;       /* Number of slots allocated for aOp[] */  Op *aOp;            /* Space to hold the virtual machine's program */  int nLabel;         /* Number of labels used */  int nLabelAlloc;    /* Number of slots allocated in aLabel[] */  int *aLabel;        /* Space to hold the labels */  Mem *aStack;        /* The operand stack, except string values */  Mem *pTos;          /* Top entry in the operand stack */  char **zArgv;       /* Text values used by the callback */  char **azColName;   /* Becomes the 4th parameter to callbacks */  int nCursor;        /* Number of slots in aCsr[] */  Cursor *aCsr;       /* One element of this array for each open cursor */  Sorter *pSort;      /* A linked list of objects to be sorted */  FILE *pFile;        /* At most one open file handler */  int nField;         /* Number of file fields */  char **azField;     /* Data for each file field */  int nVar;           /* Number of entries in azVariable[] */  char **azVar;       /* Values for the OP_Variable opcode */  int *anVar;         /* Length of each value in azVariable[] */  u8 *abVar;          /* TRUE if azVariable[i] needs to be sqliteFree()ed */  char *zLine;            /* A single line from the input file */  int nLineAlloc;         /* Number of spaces allocated for zLine */  int magic;              /* Magic number for sanity checking */  int nMem;               /* Number of memory locations currently allocated */  Mem *aMem;              /* The memory locations */  Agg agg;                /* Aggregate information */  int nSet;               /* Number of sets allocated */  Set *aSet;              /* An array of sets */  int nCallback;          /* Number of callbacks invoked so far */  Keylist *pList;         /* A list of ROWIDs */  int keylistStackDepth;  /* The size of the "keylist" stack */  Keylist **keylistStack; /* The stack used by opcodes ListPush & ListPop */  int contextStackDepth;  /* The size of the "context" stack */  Context *contextStack;  /* Stack used by opcodes ContextPush & ContextPop*/  int pc;                 /* The program counter */  int rc;                 /* Value to return */  unsigned uniqueCnt;     /* Used by OP_MakeRecord when P2!=0 */  int errorAction;        /* Recovery action to do in case of an error */  int undoTransOnError;   /* If error, either ROLLBACK or COMMIT */  int inTempTrans;        /* True if temp database is transactioned */  int returnStack[100];   /* Return address stack for OP_Gosub & OP_Return */  int returnDepth;        /* Next unused element in returnStack[] */  int nResColumn;         /* Number of columns in one row of the result set */  char **azResColumn;     /* Values for one row of result */   int popStack;           /* Pop the stack this much on entry to VdbeExec() */  char *zErrMsg;          /* Error message written here */  u8 explain;             /* True if EXPLAIN present on SQL command */};/*** The following are allowed values for Vdbe.magic*/#define VDBE_MAGIC_INIT     0x26bceaa5    /* Building a VDBE program */#define VDBE_MAGIC_RUN      0xbdf20da3    /* VDBE is ready to execute */#define VDBE_MAGIC_HALT     0x519c2973    /* VDBE has completed execution */#define VDBE_MAGIC_DEAD     0xb606c3c8    /* The VDBE has been deallocated *//*** Function prototypes*/void sqliteVdbeCleanupCursor(Cursor*);void sqliteVdbeSorterReset(Vdbe*);void sqliteVdbeAggReset(Agg*);void sqliteVdbeKeylistFree(Keylist*);void sqliteVdbePopStack(Vdbe*,int);int sqliteVdbeCursorMoveto(Cursor*);int sqliteVdbeByteSwap(int);#if !defined(NDEBUG) || defined(VDBE_PROFILE)void sqliteVdbePrintOp(FILE*, int, Op*);#endif