SQLite

**
*************************************************************************
** This file contains SQLite's grammar for SQL.  Process this file
** using the lemon parser generator to generate C code that runs
** the parser.  Lemon will also generate a header file containing
** numeric codes for all of the tokens.
**
** @(#) $Id: parse.y,v 1.38 2001/11/06 04:00:18 drh Exp $
*/
%token_prefix TK_
%token_type {Token}
%default_type {Token}
%extra_argument {Parse *pParse}
%syntax_error {
  sqliteSetString(&pParse->zErrMsg,"syntax error",0);
  pParse->sErrToken = TOKEN;
}
%name sqliteParser
%include {
#include "sqliteInt.h"
#include "parse.h"

/*
** A structure for holding two integers
*/
struct twoint { int a,b; };
}

// These are extra tokens used by the lexer but never seen by the
// parser.  We put them in a rule so that the parser generator will
// add them to the parse.h output file.
//
%nonassoc END_OF_FILE ILLEGAL SPACE UNCLOSED_STRING COMMENT FUNCTION

id(A) ::= VACUUM(X).     {A = X;}
id(A) ::= BEGIN(X).      {A = X;}
id(A) ::= END(X).        {A = X;}
id(A) ::= PRAGMA(X).     {A = X;}
id(A) ::= CLUSTER(X).    {A = X;}
id(A) ::= ID(X).         {A = X;}
id(A) ::= TEMP(X).       {A = X;}
id(A) ::= OFFSET(X).     {A = X;}

// And "ids" is an identifer-or-string.
//
%type ids {Token}
ids(A) ::= id(X).        {A = X;}
ids(A) ::= STRING(X).    {A = X;}

}
%type joinop {int}
joinop(A) ::= UNION.      {A = TK_UNION;}
joinop(A) ::= UNION ALL.  {A = TK_ALL;}
joinop(A) ::= INTERSECT.  {A = TK_INTERSECT;}
joinop(A) ::= EXCEPT.     {A = TK_EXCEPT;}
oneselect(A) ::= SELECT distinct(D) selcollist(W) from(X) where_opt(Y)
                 groupby_opt(P) having_opt(Q) orderby_opt(Z) limit_opt(L). {
  A = sqliteSelectNew(W,X,Y,P,Q,Z,D,L.a,L.b);
}

// The "distinct" nonterminal is true (1) if the DISTINCT keyword is
// present and false (0) if it is not.
//
%type distinct {int}
distinct(A) ::= DISTINCT.   {A = 1;}

groupby_opt(A) ::= .                      {A = 0;}
groupby_opt(A) ::= GROUP BY exprlist(X).  {A = X;}

%type having_opt {Expr*}
%destructor having_opt {sqliteExprDelete($$);}
having_opt(A) ::= .                {A = 0;}
having_opt(A) ::= HAVING expr(X).  {A = X;}

%type limit_opt {struct twoint}
limit_opt(A) ::= .                  {A.a = -1; A.b = 0;}
limit_opt(A) ::= LIMIT INTEGER(X).  {A.a = atoi(X.z); A.b = 0;}
limit_opt(A) ::= LIMIT INTEGER(X) limit_sep INTEGER(Y). 
                                    {A.a = atoi(X.z); A.b = atoi(Y.z);}
limit_sep ::= OFFSET.
limit_sep ::= COMMA.

/////////////////////////// The DELETE statement /////////////////////////////
//
cmd ::= DELETE FROM ids(X) where_opt(Y).
    {sqliteDeleteFrom(pParse, &X, Y);}

%type where_opt {Expr*}

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle SELECT statements in SQLite.
**
** $Id: select.c,v 1.46 2001/11/06 04:00:19 drh Exp $
*/
#include "sqliteInt.h"

/*
** Allocate a new Select structure and return a pointer to that
** structure.
*/
Select *sqliteSelectNew(
  ExprList *pEList,     /* which columns to include in the result */
  IdList *pSrc,         /* the FROM clause -- which tables to scan */
  Expr *pWhere,         /* the WHERE clause */
  ExprList *pGroupBy,   /* the GROUP BY clause */
  Expr *pHaving,        /* the HAVING clause */
  ExprList *pOrderBy,   /* the ORDER BY clause */
  int isDistinct,       /* true if the DISTINCT keyword is present */
  int nLimit,           /* LIMIT value.  -1 means not used */
  int nOffset           /* OFFSET value.  -1 means not used */
){
  Select *pNew;
  pNew = sqliteMalloc( sizeof(*pNew) );
  if( pNew==0 ){
    sqliteExprListDelete(pEList);
    sqliteIdListDelete(pSrc);
    sqliteExprDelete(pWhere);
    sqliteExprListDelete(pGroupBy);
    sqliteExprDelete(pHaving);
    sqliteExprListDelete(pOrderBy);
  }else{
    pNew->pEList = pEList;
    pNew->pSrc = pSrc;
    pNew->pWhere = pWhere;
    pNew->pGroupBy = pGroupBy;
    pNew->pHaving = pHaving;
    pNew->pOrderBy = pOrderBy;
    pNew->isDistinct = isDistinct;
    pNew->op = TK_SELECT;
    pNew->nLimit = nLimit;
    pNew->nOffset = nOffset;
  }
  return pNew;
}

/*
** Delete the given Select structure and all of its substructures.
*/

    sqliteVdbeAddOp(v, OP_MemStore, iParm, 0);
    sqliteVdbeAddOp(v, OP_Goto, 0, iBreak);
  }else

  /* If none of the above, send the data to the callback function.
  */
  {
    sqliteVdbeAddOp(v, OP_Callback, nColumn, iBreak);
  }
  return 0;
}

/*
** If the inner loop was generated using a non-null pOrderBy argument,
** then the results were placed in a sorter.  After the loop is terminated
** we need to run the sorter and output the results.  The following
** routine generates the code needed to do that.
*/
static void generateSortTail(Vdbe *v, int nColumn){
  int end = sqliteVdbeMakeLabel(v);
  int addr;
  sqliteVdbeAddOp(v, OP_Sort, 0, 0);
  addr = sqliteVdbeAddOp(v, OP_SortNext, 0, end);
  sqliteVdbeAddOp(v, OP_SortCallback, nColumn, end);
  sqliteVdbeAddOp(v, OP_Goto, 0, addr);
  sqliteVdbeResolveLabel(v, end);
  sqliteVdbeAddOp(v, OP_SortReset, 0, 0);
}

/*
** Generate code that will tell the VDBE how many columns there

    }
  }

  /* Begin generating code.
  */
  v = sqliteGetVdbe(pParse);
  if( v==0 ) return 1;

  /* Set the limiter
  */
  if( p->nLimit<=0 ){
    p->nOffset = 0;
  }else{
    if( p->nOffset<0 ) p->nOffset = 0;
    sqliteVdbeAddOp(v, OP_Limit, p->nLimit, p->nOffset);
  }
    

  /* Identify column names if we will be using in the callback.  This
  ** step is skipped if the output is going to a table or a memory cell.
  */
  if( eDest==SRT_Callback ){
    generateColumnNames(pParse, pTabList, pEList);
  }

/*
** 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 1.67 2001/11/06 04:00:19 drh Exp $
*/
#include "sqlite.h"
#include "hash.h"
#include "vdbe.h"
#include "parse.h"
#include "btree.h"
#include <stdio.h>

  IdList *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 */
  int op;                /* One of: TK_UNION TK_ALL TK_INTERSECT TK_EXCEPT */
  Select *pPrior;        /* Prior select in a compound select statement */
  int nLimit, nOffset;   /* LIMIT and OFFSET values.  -1 means not used */
};

/*
** The results of a select can be distributed in several ways.
*/
#define SRT_Callback     1  /* Invoke a callback with each row of result */
#define SRT_Mem          2  /* Store result in a memory cell */

** Internal function prototypes
*/
int sqliteStrICmp(const char *, const char *);
int sqliteStrNICmp(const char *, const char *, int);
int sqliteHashNoCase(const char *, int);
int sqliteCompare(const char *, const char *);
int sqliteSortCompare(const char *, const char *);
void sqliteRealToSortable(double r, char *);
#ifdef MEMORY_DEBUG
  void *sqliteMalloc_(int,char*,int);
  void sqliteFree_(void*,char*,int);
  void *sqliteRealloc_(void*,int,char*,int);
  char *sqliteStrDup_(const char*,char*,int);
  char *sqliteStrNDup_(const char*, int,char*,int);
#else

void sqliteInsert(Parse*, Token*, ExprList*, Select*, IdList*);
IdList *sqliteIdListAppend(IdList*, Token*);
void sqliteIdListAddAlias(IdList*, Token*);
void sqliteIdListDelete(IdList*);
void sqliteCreateIndex(Parse*, Token*, Token*, IdList*, int, Token*, Token*);
void sqliteDropIndex(Parse*, Token*);
int sqliteSelect(Parse*, Select*, int, int);
Select *sqliteSelectNew(ExprList*,IdList*,Expr*,ExprList*,Expr*,ExprList*,
                        int,int,int);
void sqliteSelectDelete(Select*);
void sqliteDeleteFrom(Parse*, Token*, Expr*);
void sqliteUpdate(Parse*, Token*, ExprList*, Expr*);
WhereInfo *sqliteWhereBegin(Parse*, IdList*, Expr*, int);
void sqliteWhereEnd(WhereInfo*);
void sqliteExprCode(Parse*, Expr*);
void sqliteExprIfTrue(Parse*, Expr*, int);

*************************************************************************
** An tokenizer for SQL
**
** This file contains C code that splits an SQL input string up into
** individual tokens and sends those tokens one-by-one over to the
** parser for analysis.
**
** $Id: tokenize.c,v 1.32 2001/11/06 04:00:19 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include <stdlib.h>

/*

  { "INSERT",            0, TK_INSERT,           0 },
  { "INTERSECT",         0, TK_INTERSECT,        0 },
  { "INTO",              0, TK_INTO,             0 },
  { "IS",                0, TK_IS,               0 },
  { "ISNULL",            0, TK_ISNULL,           0 },
  { "KEY",               0, TK_KEY,              0 },
  { "LIKE",              0, TK_LIKE,             0 },
  { "LIMIT",             0, TK_LIMIT,            0 },
  { "NOT",               0, TK_NOT,              0 },
  { "NOTNULL",           0, TK_NOTNULL,          0 },
  { "NULL",              0, TK_NULL,             0 },
  { "OFFSET",            0, TK_OFFSET,           0 },
  { "ON",                0, TK_ON,               0 },
  { "OR",                0, TK_OR,               0 },
  { "ORDER",             0, TK_ORDER,            0 },
  { "PRAGMA",            0, TK_PRAGMA,           0 },
  { "PRIMARY",           0, TK_PRIMARY,          0 },
  { "ROLLBACK",          0, TK_ROLLBACK,         0 },
  { "SELECT",            0, TK_SELECT,           0 },

**
*************************************************************************
** Utility functions used throughout sqlite.
**
** This file contains functions for allocating memory, comparing
** strings, and stuff like that.
**
** $Id: util.c,v 1.31 2001/11/06 04:00:19 drh Exp $
*/
#include "sqliteInt.h"
#include <stdarg.h>
#include <ctype.h>

/*
** If malloc() ever fails, this global variable gets set to 1.

      a += len;
      b += len;
    }
  }
  if( *a=='-' ) res = -res;
  return res;
}

/*
** Some powers of 64.  These numbers and their recipricals should
** all have exact representations in the floating point format.
*/
#define _64e3  (64.0 * 64.0 * 64.0)
#define _64e4  (64.0 * 64.0 * 64.0 * 64.0)
#define _64e15 (_64e3 * _64e4 * _64e4 * _64e4)
#define _64e16 (_64e4 * _64e4 * _64e4 * _64e4)
#define _64e63 (_64e15 * _64e16 * _64e16 * _64e16)
#define _64e64 (_64e16 * _64e16 * _64e16 * _64e16)

/*
** The following procedure converts a double-precision floating point
** number into a string.  The resulting string has the property that
** two such strings comparied using strcmp() or memcmp() will give the
** same results as comparing the original floating point numbers.
**
** This routine is used to generate database keys from floating point
** numbers such that the keys sort in the same order as the original
** floating point numbers even though the keys are compared using
** memcmp().
**
** The calling function should have allocated at least 14 characters
** of space for the buffer z[].
*/
void sqliteRealToSortable(double r, char *z){
  int neg;
  int exp;
  int cnt = 0;

  /* This array maps integers between 0 and 63 into base-64 digits.
  ** The digits must be chosen such at their ASCII codes are increasing.
  ** This means we can not use the traditional base-64 digit set. */
  static const char zDigit[] = 
     "0123456789"
     "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
     "abcdefghijklmnopqrstuvwxyz"
     "|~";
  if( r<0.0 ){
    neg = 1;
    r = -r;
    *z++ = '-';
  } else {
    neg = 0;
    *z++ = '0';
  }
  exp = 0;

  if( r==0.0 ){
    exp = -1024;
  }else if( r<(0.5/64.0) ){
    while( r < 0.5/_64e64 && exp > -961  ){ r *= _64e64;  exp -= 64; }
    while( r < 0.5/_64e16 && exp > -1009 ){ r *= _64e16;  exp -= 16; }
    while( r < 0.5/_64e4  && exp > -1021 ){ r *= _64e4;   exp -= 4; }
    while( r < 0.5/64.0   && exp > -1024 ){ r *= 64.0;    exp -= 1; }
  }else if( r>=0.5 ){
    while( r >= 0.5*_64e63 && exp < 960  ){ r *= 1.0/_64e64; exp += 64; }
    while( r >= 0.5*_64e15 && exp < 1008 ){ r *= 1.0/_64e16; exp += 16; }
    while( r >= 0.5*_64e3  && exp < 1020 ){ r *= 1.0/_64e4;  exp += 4; }
    while( r >= 0.5        && exp < 1023 ){ r *= 1.0/64.0;   exp += 1; }
  }
  if( neg ){
    exp = -exp;
    r = -r;
  }
  exp += 1024;
  r += 0.5;
  if( exp<0 ) return;
  if( exp>=2048 || r>=1.0 ){
    strcpy(z, "~~~~~~~~~~~~");
    return;
  }
  *z++ = zDigit[(exp>>6)&0x3f];
  *z++ = zDigit[exp & 0x3f];
  while( r>0.0 && cnt<10 ){
    int digit;
    r *= 64.0;
    digit = r;
    assert( digit>=0 && digit<64 );
    *z++ = zDigit[digit & 0x3f];
    r -= digit;
    cnt++;
  }
  *z = 0;
}

#ifdef SQLITE_UTF8
/*
** X is a pointer to the first byte of a UTF-8 character.  Increment
** X so that it points to the next character.  This only works right
** if X points to a well-formed UTF-8 string.
*/

** type to the other occurs as necessary.
** 
** Most of the code in this file is taken up by the sqliteVdbeExec()
** function which does the work of interpreting a VDBE program.
** But other routines are also provided to help in building up
** a program instruction by instruction.
**
** $Id: vdbe.c,v 1.93 2001/11/06 04:00:19 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** SQL is translated into a sequence of instructions to be
** executed by a virtual machine.  Each instruction is an instance

};

/* 
** 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 30

/*
** A single level of the stack is an instance of the following
** structure.  Except, string values are stored on a separate
** list of of pointers to character.  The reason for storing
** strings separately is so that they can be easily passed
** to the callback function.
*/
struct Stack {
  int i;         /* Integer value */
  int n;         /* Number of characters in string value, including '\0' */
  int flags;     /* Some combination of STK_Null, STK_Str, STK_Dyn, etc. */
  double r;      /* Real value */
  char z[NBFS];  /* Space for short strings */
};
typedef struct Stack Stack;

/*
** Memory cells use the same structure as the stack except that space
** for an arbitrary string is added.
*/

** Allowed values for Stack.flags
*/
#define STK_Null      0x0001   /* Value is NULL */
#define STK_Str       0x0002   /* Value is a string */
#define STK_Int       0x0004   /* Value is an integer */
#define STK_Real      0x0008   /* Value is a real number */
#define STK_Dyn       0x0010   /* Need to call sqliteFree() on zStack[*] */
#define STK_Static    0x0020   /* zStack[] points to a static string */

/*
** 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.

  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 nFetch;         /* Number of OP_Fetch instructions executed */
  int nCallback;      /* Number of callbacks invoked so far */
  int iLimit;         /* Limit on the number of callbacks remaining */
  int iOffset;        /* Offset before beginning to do callbacks */
};

/*
** Create a new virtual database engine.
*/
Vdbe *sqliteVdbeCreate(sqlite *db){
  Vdbe *p;

** NULLs are converted into an empty string.
*/
#define Stringify(P,I) \
   ((P->aStack[I].flags & STK_Str)==0 ? hardStringify(P,I) : 0)
static int hardStringify(Vdbe *p, int i){
  Stack *pStack = &p->aStack[i];
  char **pzStack = &p->zStack[i];

  int fg = pStack->flags;
  if( fg & STK_Real ){
    sprintf(pStack->z,"%.15g",pStack->r);
  }else if( fg & STK_Int ){
    sprintf(pStack->z,"%d",pStack->i);
  }else{

    pStack->z[0] = 0;


  }
  *pzStack = pStack->z;

  pStack->n = strlen(*pzStack)+1;
  pStack->flags = STK_Str;
  return 0;
}

/*
** Release the memory associated with the given stack level
*/
#define Release(P,I)  if((P)->aStack[I].flags&STK_Dyn){ hardRelease(P,I); }
static void hardRelease(Vdbe *p, int i){
  sqliteFree(p->zStack[i]);
  p->zStack[i] = 0;
  p->aStack[i].flags &= ~(STK_Str|STK_Dyn|STK_Static);
}

/*
** Convert the given stack entity into a integer if it isn't one
** already.
**
** Any prior string or real representation is invalidated.  

    for(i=oldAlloc; i<p->nStackAlloc; i++){
      p->zStack[i] = 0;
      p->aStack[i].flags = 0;
    }
  }
  return 0;
}

/*
** Return TRUE if zNum is a floating-point or integer number.
*/
static int isNumber(const char *zNum){
  if( *zNum=='-' || *zNum=='+' ) zNum++;
  if( !isdigit(*zNum) ) return 0;
  while( isdigit(*zNum) ) zNum++;
  if( *zNum==0 ) return 1;
  if( *zNum!='.' ) return 0;
  zNum++;
  if( !isdigit(*zNum) ) return 0;
  while( isdigit(*zNum) ) zNum++;
  if( *zNum==0 ) return 1;
  if( *zNum!='e' && *zNum!='E' ) return 0;
  zNum++;
  if( *zNum=='-' || *zNum=='+' ) zNum++;
  if( !isdigit(*zNum) ) return 0;
  while( isdigit(*zNum) ) zNum++;
  return *zNum==0;
}

/*
** Delete a keylist
*/
static void KeylistFree(Keylist *p){
  while( p ){
    Keylist *pNext = p->pNext;

  "Column",            "KeyAsData",         "Recno",             "FullKey",
  "Rewind",            "Next",              "Destroy",           "Clear",
  "CreateIndex",       "CreateTable",       "Reorganize",        "BeginIdx",
  "NextIdx",           "PutIdx",            "DeleteIdx",         "MemLoad",
  "MemStore",          "ListWrite",         "ListRewind",        "ListRead",
  "ListReset",         "SortPut",           "SortMakeRec",       "SortMakeKey",
  "Sort",              "SortNext",          "SortCallback",      "SortReset",
  "FileOpen",          "FileRead",          "FileColumn",        "AggReset",
  "AggFocus",          "AggIncr",           "AggNext",           "AggSet",
  "AggGet",            "SetInsert",         "SetFound",          "SetNotFound",
  "MakeRecord",        "MakeKey",           "MakeIdxKey",        "Goto",
  "If",                "Halt",              "ColumnCount",       "ColumnName",
  "Callback",          "NullCallback",      "Integer",           "String",

  "Pop",               "Dup",               "Pull",              "Add",
  "AddImm",            "Subtract",          "Multiply",          "Divide",
  "Remainder",         "BitAnd",            "BitOr",             "BitNot",
  "ShiftLeft",         "ShiftRight",        "AbsValue",          "Precision",
  "Min",               "Max",               "Like",              "Glob",
  "Eq",                "Ne",                "Lt",                "Le",
  "Gt",                "Ge",                "IsNull",            "NotNull",
  "Negative",          "And",               "Or",                "Not",
  "Concat",            "Noop",              "Strlen",            "Substr",
  "Limit",
};

/*
** Given the name of an opcode, return its number.  Return 0 if
** there is no match.
**
** This routine is used for testing and debugging.

  z = pOp->p3;
  if( z==0 ){
    zStack[i] = 0;
    aStack[i].flags = STK_Null;
  }else{
    zStack[i] = z;
    aStack[i].n = strlen(z) + 1;
    aStack[i].flags = STK_Str | STK_Static;
  }
  break;
}















/* Opcode: Pop P1 * *
**
** P1 elements are popped off of the top of stack and discarded.
*/
case OP_Pop: {
  PopStack(p, pOp->p1);
  break;

** Also see the Pull instruction.
*/
case OP_Dup: {
  int i = p->tos - pOp->p1;
  int j = ++p->tos;
  VERIFY( if( i<0 ) goto not_enough_stack; )
  VERIFY( if( NeedStack(p, p->tos) ) goto no_mem; )
  memcpy(&aStack[j], &aStack[i], sizeof(aStack[i])-NBFS);
  if( aStack[j].flags & STK_Str ){
    if( aStack[j].flags & STK_Static ){
      zStack[j] = zStack[i];
      aStack[j].flags = STK_Str | STK_Static;
    }else if( aStack[i].n<=NBFS ){
      memcpy(aStack[j].z, zStack[i], aStack[j].n);
      zStack[j] = aStack[j].z;
      aStack[j].flags = STK_Str;
    }else{
      zStack[j] = sqliteMalloc( aStack[j].n );
      if( zStack[j]==0 ) goto no_mem;
      memcpy(zStack[j], zStack[i], aStack[j].n);

      aStack[j].flags = STK_Str | STK_Dyn;
    }
  }
  break;
}

/* Opcode: Pull P1 * *
**
** The P1-th element is removed from its current location on 

  Stack ts;
  char *tz;
  VERIFY( if( from<0 ) goto not_enough_stack; )
  ts = aStack[from];
  tz = zStack[from];
  for(i=from; i<to; i++){
    aStack[i] = aStack[i+1];
    if( aStack[i].flags & (STK_Dyn|STK_Static) ){
      zStack[i] = zStack[i+1];
    }else{
      zStack[i] = aStack[i].z;
    }
  }
  aStack[to] = ts;
  if( aStack[to].flags & (STK_Dyn|STK_Static) ){
    zStack[to] = tz;
  }else{
    zStack[to] = aStack[to].z;
  }
  break;
}

/* Opcode: ColumnCount P1 * *
**
** Specify the number of column values that will appear in the
** array passed as the 4th parameter to the callback.  No checking

*/
case OP_ColumnName: {
  p->azColName[pOp->p1] = pOp->p3 ? pOp->p3 : "";
  p->nCallback = 0;
  break;
}

/* Opcode: Callback P1 P2 *
**
** Pop P1 values off the stack and form them into an array.  Then
** invoke the callback function using the newly formed array as the
** 3rd parameter.
**
** If the offset counter (set by the OP_Limit opcode) is positive,
** then decrement the counter and do not invoke the callback.
** 
** If the callback is invoked, then after the callback returns
** decrement the limit counter.  When the limit counter reaches
** zero, jump to address P2.
*/
case OP_Callback: {
  int i = p->tos - pOp->p1 + 1;
  int j;
  VERIFY( if( i<0 ) goto not_enough_stack; )
  VERIFY( if( NeedStack(p, p->tos+2) ) goto no_mem; )
  for(j=i; j<=p->tos; j++){
    if( (aStack[j].flags & STK_Null)==0 ){
      if( Stringify(p, j) ) goto no_mem;
    }
  }
  zStack[p->tos+1] = 0;
  if( xCallback!=0 ){
    if( p->iOffset>0 ){
      p->iOffset--;
    }else{
      if( xCallback(pArg, pOp->p1, &zStack[i], p->azColName)!=0 ){
        rc = SQLITE_ABORT;
      }
      p->nCallback++;
      if( p->iLimit>0 ){
        p->iLimit--;
        if( p->iLimit==0 ){
          pc = pOp->p2 - 1;
        }
      }
    }
  }
  PopStack(p, pOp->p1);
  if( sqlite_malloc_failed ) goto no_mem;
  break;
}

/* Opcode: NullCallback P1 * *

** specified by the integer and push the floating-point number back onto
** the stack. 
*/
case OP_Precision: {
  int tos = p->tos;
  int nos = tos - 1;
  int nDigit;
  int len;
  double v;
  char *zNew;

  VERIFY( if( nos<0 ) goto not_enough_stack; )
  Realify(p, tos);
  Integerify(p, nos);
  nDigit = aStack[nos].i;
  if( nDigit<0 ) nDigit = 0;
  if( nDigit>30 ) nDigit = 30;
  v = aStack[tos].r;
  zNew = sqlite_mprintf("%.*f", nDigit, v);
  if( zNew==0 ) goto no_mem;
  POPSTACK;
  Release(p, nos);
  aStack[nos].n = len = strlen(zNew) + 1;
  if( len<=NBFS ){
    strcpy(aStack[nos].z, zNew);
    zStack[nos] = aStack[nos].z;
    aStack[nos].flags = STK_Str;
    sqliteFree(zNew);
  }else{
    zStack[nos] = zNew;
    aStack[nos].flags = STK_Str | STK_Dyn;
  }
  break;
}

/* Opcode: Max * * *
**
** Pop the top two elements from the stack then push back the
** largest of the two.
*/
/* Opcode: Min * * *
**
** Pop the top two elements from the stack then push back the
** smaller of the two. 
*/
case OP_Min:
case OP_Max: {
  int tos = p->tos;
  int nos = tos - 1;
  int a,b;
  int ft, fn;
  int copy = 0;
  VERIFY( if( nos<0 ) goto not_enough_stack; )
  ft = aStack[tos].flags;
  fn = aStack[nos].flags;
  if( pOp->opcode==OP_Max ){
    a = tos;




    b = nos;

  }else{












    a = nos;
    b = tos;
  }














  if( fn & STK_Null ){
    copy = 1;
  }else if( ft & STK_Null ){
    copy = 0;
  }else if( (ft & fn & STK_Int)==STK_Int ){
    copy = aStack[a].i>aStack[b].i;
  }else if( ( (ft|fn) & (STK_Int|STK_Real) ) !=0 ){
    Realify(p, tos);
    Realify(p, nos);
    copy = aStack[a].r>aStack[b].r;
  }else{
    if( Stringify(p, tos) || Stringify(p, nos) ) goto no_mem;
    copy = sqliteCompare(zStack[a],zStack[b])>0;
  }
  if( copy ){
    Release(p, nos);
    aStack[nos] = aStack[tos];
    if( aStack[nos].flags & (STK_Dyn|STK_Static) ){
      zStack[nos] = zStack[tos];
    }else{
      zStack[nos] = aStack[nos].z;
    }
    zStack[tos] = 0;
    aStack[tos].flags = 0;
  }else{
    Release(p, tos);
  }
  p->tos = nos;
  break;

** If P2 is not zero, then the original entries remain on the stack
** and the new key is pushed on top.  If P2 is zero, the original
** data is popped off the stack first then the new key is pushed
** back in its place.
**
** See also: MakeIdxKey, SortMakeKey
*/









































/* Opcode: MakeIdxKey P1 * *
**
** Convert the top P1 entries of the stack into a single entry suitable
** for use as the key in an index.  In addition, take one additional integer
** off of the stack, treat that integer as a four-byte record number, and
** append the four bytes to the key.  Thus a total of P1+1 entries are
** popped from the stack for this instruction and a single entry is pushed
** back.  The first P1 entries that are popped are strings and the last
** entry (the lowest on the stack) is an integer record number.
**
** The converstion of the first P1 string entries occurs just like in
** MakeKey.  Each entry is separated from the others by a null.
** The entire concatenation is null-terminated.  The lowest entry
** in the stack is the first field and the top of the stack becomes the
** last.
**
** See also:  MakeKey, SortMakeKey
*/
case OP_MakeIdxKey:
case OP_MakeKey: {
  char *zNewKey;
  int nByte;
  int nField;
  int addRowid;
  int i, j;


  addRowid = pOp->opcode==OP_MakeIdxKey;
  nField = pOp->p1;
  VERIFY( if( p->tos+1+addRowid<nField ) goto not_enough_stack; )
  nByte = 0;
  for(i=p->tos-nField+1; i<=p->tos; i++){
    int flags = aStack[i].flags;
    int len;
    char *z;
    if( flags & STK_Null ){
      nByte += 2;
    }else if( flags & STK_Real ){
      z = aStack[i].z;
      sqliteRealToSortable(aStack[i].r, &z[1]);
      z[0] = 0;
      Release(p, i);
      len = strlen(&z[1]);
      zStack[i] = 0;
      aStack[i].flags = STK_Real;
      aStack[i].n = len+2;
      nByte += aStack[i].n;
    }else if( flags & STK_Int ){
      z = aStack[i].z;
      aStack[i].r = aStack[i].i;
      sqliteRealToSortable(aStack[i].r, &z[1]);
      z[0] = 0;
      Release(p, i);
      len = strlen(&z[1]);
      zStack[i] = 0;
      aStack[i].flags = STK_Int;
      aStack[i].n = len+2;
      nByte += aStack[i].n;
    }else{
      assert( flags & STK_Str );
      if( isNumber(zStack[i]) ){
        aStack[i].r = atof(zStack[i]);
        Release(p, i);
        z = aStack[i].z;
        sqliteRealToSortable(aStack[i].r, &z[1]);
        z[0] = 0;
        len = strlen(&z[1]);
        zStack[i] = 0;
        aStack[i].flags = STK_Real;
        aStack[i].n = len+2;
      }
      nByte += aStack[i].n;
    }
  }
  if( nByte+sizeof(u32)>MAX_BYTES_PER_ROW ){
    rc = SQLITE_TOOBIG;
    goto abort_due_to_error;
  }
  if( addRowid ) nByte += sizeof(u32);
  zNewKey = sqliteMalloc( nByte );
  if( zNewKey==0 ) goto no_mem;
  j = 0;
  for(i=p->tos-nField+1; i<=p->tos; i++){
    if( aStack[i].flags & STK_Null ){
      zNewKey[j++] = 0;
      zNewKey[j++] = 0;
    }else{
      memcpy(&zNewKey[j], zStack[i] ? zStack[i] : aStack[i].z, aStack[i].n);
      j += aStack[i].n;
    }
  }
  if( addRowid ){
    u32 iKey;
    Integerify(p, p->tos-nField);
    iKey = bigEndian(aStack[p->tos-nField].i);
    memcpy(&zNewKey[j], &iKey, sizeof(u32));
  }
  if( pOp->p2==0 ) PopStack(p, nField+addRowid);
  VERIFY( NeedStack(p, p->tos+1); )
  p->tos++;
  aStack[p->tos].n = nByte;
  aStack[p->tos].flags = STK_Str|STK_Dyn;
  zStack[p->tos] = zNewKey;
  break;
}

** in the data.
**
** If the KeyAsData opcode has previously executed on this cursor,
** then the field might be extracted from the key rather than the
** data.
*/
case OP_Column: {
  int amt, offset, end, payloadSize;
  int i = pOp->p1;
  int p2 = pOp->p2;
  int tos = p->tos+1;
  Cursor *pC;
  BtCursor *pCrsr;
  int idxWidth;
  unsigned char aHdr[10];

    }

    /* amt and offset now hold the offset to the start of data and the
    ** amount of data.  Go get the data and put it on the stack.
    */
    if( amt==0 ){
      aStack[tos].flags = STK_Null;
    }else if( amt<=NBFS ){
      (*xRead)(pCrsr, offset, amt, aStack[tos].z);
      aStack[tos].flags = STK_Str;
      zStack[tos] = aStack[tos].z;
      aStack[tos].n = amt;
    }else{
      char *z = sqliteMalloc( amt );
      if( z==0 ) goto no_mem;
      (*xRead)(pCrsr, offset, amt, z);
      aStack[tos].flags = STK_Str | STK_Dyn;
      zStack[tos] = z;
      aStack[tos].n = amt;

    char *z;

    sqliteBtreeKeySize(pCrsr, &amt);
    if( amt<=0 ){
      rc = SQLITE_CORRUPT;
      goto abort_due_to_error;
    }
    if( amt>NBFS ){
      z = sqliteMalloc( amt );
      aStack[tos].flags = STK_Str | STK_Dyn;
    }else{
      z = aStack[tos].z;
      aStack[tos].flags = STK_Str;
    }
    sqliteBtreeKey(pCrsr, 0, amt, z);
    zStack[tos] = z;

    aStack[tos].n = amt;
  }
  break;
}

/* Opcode: Rewind P1 * *
**

**
** In the current implementation, this is a no-op.
*/
case OP_Reorganize: {
  /* This is currently a no-op */
  break;
}

/* Opcode:  Limit P1 P2 *
**
** Set a limit and offset on callbacks.  P1 is the limit and P2 is
** the offset.  If the offset counter is positive, no callbacks are
** invoked but instead the counter is decremented.  Once the offset
** counter reaches zero, callbacks are invoked and the limit
** counter is decremented.  When the limit counter reaches zero,
** the OP_Callback or OP_SortCallback instruction executes a jump
** that should end the query.
**
** This opcode is used to implement the "LIMIT x OFFSET y" clause
** of a SELECT statement.
*/
case OP_Limit: {
  p->iLimit = pOp->p1;
  p->iOffset = pOp->p2;
  break;
}

/* Opcode: ListWrite * * *
**
** Write the integer on the top of the stack
** into the temporary storage list.
*/
case OP_ListWrite: {

  }
  break;
}

/* Opcode: SortPut * * *
**
** The TOS is the key and the NOS is the data.  Pop both from the stack
** and put them on the sorter.  The key and data should have been
** made using SortMakeKey and SortMakeRec, respectively.
*/
case OP_SortPut: {
  int tos = p->tos;
  int nos = tos - 1;
  Sorter *pSorter;
  VERIFY( if( tos<1 ) goto not_enough_stack; )
  if( Stringify(p, tos) || Stringify(p, nos) ) goto no_mem;
  pSorter = sqliteMalloc( sizeof(Sorter) );
  if( pSorter==0 ) goto no_mem;
  pSorter->pNext = p->pSort;
  p->pSort = pSorter;
  assert( aStack[tos].flags & STK_Dyn );
  assert( aStack[nos].flags & STK_Dyn );
  pSorter->nKey = aStack[tos].n;
  pSorter->zKey = zStack[tos];
  pSorter->nData = aStack[nos].n;
  pSorter->pData = zStack[nos];
  aStack[tos].flags = 0;
  aStack[nos].flags = 0;
  zStack[tos] = 0;

    sqliteFree(pSorter);
  }else{
    pc = pOp->p2 - 1;
  }
  break;
}

/* Opcode: SortCallback P1 P2 *
**
** The top of the stack contains a callback record built using
** the SortMakeRec operation with the same P1 value as this
** instruction.  Pop this record from the stack and invoke the
** callback on it.
**
** If the offset counter (set by the OP_Limit opcode) is positive,
** then decrement the counter and do not invoke the callback.
** 
** If the callback is invoked, then after the callback returns
** decrement the limit counter.  When the limit counter reaches
** zero, jump to address P2.
*/
case OP_SortCallback: {
  int i = p->tos;
  VERIFY( if( i<0 ) goto not_enough_stack; )
  if( xCallback!=0 ){
    if( p->iOffset>0 ){
      p->iOffset--;
    }else{
      if( xCallback(pArg, pOp->p1, (char**)zStack[i], p->azColName)!=0 ){
        rc = SQLITE_ABORT;
      }
      p->nCallback++;
      if( p->iLimit>0 ){
        p->iLimit--;
        if( p->iLimit==0 ){
          pc = pOp->p2 - 1;
        }
      }
    }
    p->nCallback++;
  }
  POPSTACK;
  if( sqlite_malloc_failed ) goto no_mem;
  break;
}

    sqliteSetString(pzErrMsg,"unable to open file: ", pOp->p3, 0);
    rc = SQLITE_ERROR;
    goto cleanup;
  }
  break;
}


























/* Opcode: FileRead P1 P2 P3
**
** Read a single line of input from the open file (the file opened using
** FileOpen).  If we reach end-of-file, jump immediately to P2.  If
** we are able to get another line, split the line apart using P3 as
** a delimiter.  There should be P1 fields.  If the input line contains
** more than P1 fields, ignore the excess.  If the input line contains

** Pop a single value of the stack and store that value into memory
** location P1.  P1 should be a small integer since space is allocated
** for all memory locations between 0 and P1 inclusive.
*/
case OP_MemStore: {
  int i = pOp->p1;
  int tos = p->tos;

  char *zOld;
  Mem *pMem;
  VERIFY( if( tos<0 ) goto not_enough_stack; )
  if( i>=p->nMem ){
    int nOld = p->nMem;
    Mem *aMem;
    p->nMem = i + 5;
    aMem = sqliteRealloc(p->aMem, p->nMem*sizeof(p->aMem[0]));
    if( aMem==0 ) goto no_mem;
    p->aMem = aMem;
    if( nOld<p->nMem ){
      memset(&p->aMem[nOld], 0, sizeof(p->aMem[0])*(p->nMem-nOld));
    }
  }
  pMem = &p->aMem[i];
  if( pMem->s.flags & STK_Dyn ){
    zOld = pMem->z;
  }else{
    zOld = 0;
  }
  pMem->s = aStack[tos];
  if( pMem->s.flags & (STK_Static|STK_Dyn) ){
    pMem->z = zStack[tos];
  }else{
    pMem->z = pMem->s.z;
  }
  if( zOld ) sqliteFree(zOld);
  zStack[tos] = 0;
  aStack[tos].flags = 0;
  POPSTACK;
  break;
}

/* Opcode: MemLoad P1 * *
**
** Push a copy of the value in memory location P1 onto the stack.
*/
case OP_MemLoad: {
  int tos = ++p->tos;
  int i = pOp->p1;
  VERIFY( if( NeedStack(p, tos) ) goto no_mem; )
  if( i<0 || i>=p->nMem ){
    aStack[tos].flags = STK_Null;
    zStack[tos] = 0;
  }else{
    aStack[tos] = p->aMem[i].s;
    if( aStack[tos].flags & STK_Dyn ){
      char *z = sqliteMalloc(aStack[tos].n);
      if( z==0 ) goto no_mem;
      memcpy(z, p->aMem[i].z, aStack[tos].n);
      zStack[tos] = z;
      aStack[tos].flags |= STK_Dyn;
    }else if( aStack[tos].flags & STK_Static ){
      zStack[tos] = p->aMem[i].z;
    }else if( aStack[tos].flags & STK_Str ){
      zStack[tos] = aStack[tos].z;
    }
  }
  break;
}

/* Opcode: AggReset * P2 *
**

    char *zOld;
    if( pMem->s.flags & STK_Dyn ){
      zOld = pMem->z;
    }else{
      zOld = 0;
    }
    pMem->s = aStack[tos];
    if( pMem->s.flags & STK_Dyn ){
      pMem->z = zStack[tos];
      zStack[tos] = 0;
      aStack[tos].flags = 0;
    }else if( pMem->s.flags & STK_Static ){
      pMem->z = zStack[tos];

    }else if( pMem->s.flags & STK_Str ){
      pMem->z = pMem->s.z;
    }
    if( zOld ) sqliteFree(zOld);
  }
  POPSTACK;
  break;
}

    pc = pOp->p2 - 1;
  } else {
    p->agg.pCurrent = sqliteHashData(p->agg.pSearch);
  }
  break;
}















/* Opcode: SetInsert P1 * P3
**
** If Set P1 does not exist then create it.  Then insert value
** P3 into that set.  If P3 is NULL, then insert the top of the
** stack into the set.
*/
case OP_SetInsert: {

*************************************************************************
** Header file for the Virtual DataBase Engine (VDBE)
**
** This header defines the interface to the virtual database engine
** or VDBE.  The VDBE implements an abstract machine that runs a
** simple program to access and modify the underlying database.
**
** $Id: vdbe.h,v 1.33 2001/11/06 04:00:19 drh Exp $
*/
#ifndef _SQLITE_VDBE_H_
#define _SQLITE_VDBE_H_
#include <stdio.h>

/*
** A single VDBE is an opaque structure named "Vdbe".  Only routines

#define OP_SortNext           46
#define OP_SortCallback       47
#define OP_SortReset          48

#define OP_FileOpen           49
#define OP_FileRead           50
#define OP_FileColumn         51


#define OP_AggReset           52
#define OP_AggFocus           53
#define OP_AggIncr            54
#define OP_AggNext            55
#define OP_AggSet             56
#define OP_AggGet             57

#define OP_SetInsert          58
#define OP_SetFound           59
#define OP_SetNotFound        60


#define OP_MakeRecord         61
#define OP_MakeKey            62
#define OP_MakeIdxKey         63

#define OP_Goto               64
#define OP_If                 65
#define OP_Halt               66

#define OP_ColumnCount        67
#define OP_ColumnName         68
#define OP_Callback           69
#define OP_NullCallback       70

#define OP_Integer            71
#define OP_String             72

#define OP_Pop                73
#define OP_Dup                74
#define OP_Pull               75

#define OP_Add                76
#define OP_AddImm             77
#define OP_Subtract           78
#define OP_Multiply           79
#define OP_Divide             80
#define OP_Remainder          81
#define OP_BitAnd             82
#define OP_BitOr              83
#define OP_BitNot             84
#define OP_ShiftLeft          85
#define OP_ShiftRight         86
#define OP_AbsValue           87
#define OP_Precision          88
#define OP_Min                89
#define OP_Max                90
#define OP_Like               91
#define OP_Glob               92
#define OP_Eq                 93
#define OP_Ne                 94
#define OP_Lt                 95
#define OP_Le                 96
#define OP_Gt                 97
#define OP_Ge                 98
#define OP_IsNull             99
#define OP_NotNull           100
#define OP_Negative          101
#define OP_And               102
#define OP_Or                103
#define OP_Not               104
#define OP_Concat            105
#define OP_Noop              106

#define OP_Strlen            107
#define OP_Substr            108

#define OP_Limit             109

#define OP_MAX               111

/*
** Prototypes for the VDBE interface.  See comments on the implementation
** for a description of what each of these routines does.
*/