SQLite

      callStatGet(v, regStat4, STAT_GET_ROWID, regSampleRowid);
      addrIsNull = sqlite3VdbeAddOp1(v, OP_IsNull, regSampleRowid);
      VdbeCoverage(v);
      callStatGet(v, regStat4, STAT_GET_NEQ, regEq);
      callStatGet(v, regStat4, STAT_GET_NLT, regLt);
      callStatGet(v, regStat4, STAT_GET_NDLT, regDLt);
      sqlite3VdbeAddOp4Int(v, seekOp, iTabCur, addrNext, regSampleRowid, 0);
      /* We know that the regSampleRowid row exists because it was read by
      ** the previous loop.  Thus the not-found jump of seekOp will never
      ** be taken */
      VdbeCoverageNeverTaken(v);
#ifdef SQLITE_ENABLE_STAT3
      sqlite3ExprCodeGetColumnOfTable(v, pTab, iTabCur, 
                                      pIdx->aiColumn[0], regSample);
#else
      for(i=0; i<nCol; i++){
        i16 iCol = pIdx->aiColumn[i];
        sqlite3ExprCodeGetColumnOfTable(v, pTab, iTabCur, iCol, regCol+i);
      }
      sqlite3VdbeAddOp3(v, OP_MakeRecord, regCol, nCol+1, regSample);
#endif
      sqlite3VdbeAddOp3(v, OP_MakeRecord, regTabname, 6, regTemp);
      sqlite3VdbeAddOp2(v, OP_NewRowid, iStatCur+1, regNewRowid);
      sqlite3VdbeAddOp3(v, OP_Insert, iStatCur+1, regTemp, regNewRowid);
      sqlite3VdbeAddOp2(v, OP_Goto, 1, addrNext); /* P1==1 for end-of-loop */
      sqlite3VdbeJumpHere(v, addrIsNull);
    }
#endif /* SQLITE_ENABLE_STAT3_OR_STAT4 */

    /* End of analysis */
    sqlite3VdbeJumpHere(v, addrRewind);
    sqlite3DbFree(db, aGotoChng);

  if( pIdxKey ){
    xRecordCompare = sqlite3VdbeFindCompare(pIdxKey);
    assert( pIdxKey->default_rc==1 
         || pIdxKey->default_rc==0 
         || pIdxKey->default_rc==-1
    );
  }else{
    xRecordCompare = 0; /* All keys are integers */
  }

  rc = moveToRoot(pCur);
  if( rc ){
    return rc;
  }
  assert( pCur->pgnoRoot==0 || pCur->apPage[pCur->iPage] );

  return pIdx->zColAff;
}

/*
** Compute the affinity string for table pTab, if it has not already been
** computed.  As an optimization, omit trailing SQLITE_AFF_NONE affinities.
**
** If the affinity exists (if it is no entirely SQLITE_AFF_NONE values) and
** if iReg>0 then code an OP_Affinity opcode that will set the affinities
** for register iReg and following.  Or if affinities exists and iReg==0,
** then just set the P4 operand of the previous opcode (which should  be
** an OP_MakeRecord) to the affinity string.
**
** A column affinity string has one character per column:
**
**  Character      Column affinity
**  ------------------------------
**  'a'            TEXT
**  'b'            NONE
**  'c'            NUMERIC
**  'd'            INTEGER

      sqlite3VdbeChangeP4(v, -1, zColAff, i);
    }
  }
}

/*
** Return non-zero if the table pTab in database iDb or any of its indices
** have been opened at any point in the VDBE program. This is used to see if 

** a statement of the form  "INSERT INTO <iDb, pTab> SELECT ..." can 
** run without using a temporary table for the results of the SELECT. 
*/
static int readsTable(Parse *p, int iDb, Table *pTab){
  Vdbe *v = sqlite3GetVdbe(p);
  int i;
  int iEnd = sqlite3VdbeCurrentAddr(v);
#ifndef SQLITE_OMIT_VIRTUALTABLE
  VTable *pVTab = IsVirtual(pTab) ? sqlite3GetVTable(p->db, pTab) : 0;

#ifndef SQLITE_OMIT_LOAD_EXTENSION
/*
** Interfaces for opening a shared library, finding entry points
** within the shared library, and closing the shared library.
*/
static void *winDlOpen(sqlite3_vfs *pVfs, const char *zFilename){
  HANDLE h;
#if defined(__CYGWIN__)
  int nFull = pVfs->mxPathname+1;
  char *zFull = sqlite3MallocZero( nFull );
  void *zConverted = 0;
  if( zFull==0 ){
    OSTRACE(("DLOPEN name=%s, handle=%p\n", zFilename, (void*)0));
    return 0;
  }
  if( winFullPathname(pVfs, zFilename, nFull, zFull)!=SQLITE_OK ){
    sqlite3_free(zFull);
    OSTRACE(("DLOPEN name=%s, handle=%p\n", zFilename, (void*)0));
    return 0;
  }
  zConverted = winConvertFromUtf8Filename(zFull);
  sqlite3_free(zFull);
#else
  void *zConverted = winConvertFromUtf8Filename(zFilename);
  UNUSED_PARAMETER(pVfs);
#endif
  if( zConverted==0 ){
    OSTRACE(("DLOPEN name=%s, handle=%p\n", zFilename, (void*)0));
    return 0;
  }
  if( osIsNT() ){
#if SQLITE_OS_WINRT
    h = osLoadPackagedLibrary((LPCWSTR)zConverted, 0);

**     * For each "Next", "Prev", "VNext" or "VPrev" instruction, indent
**       all opcodes that occur between the p2 jump destination and the opcode
**       itself by 2 spaces.
**
**     * For each "Goto", if the jump destination is earlier in the program
**       and ends on one of:
**          Yield  SeekGt  SeekLt  RowSetRead  Rewind
**       or if the P1 parameter is one instead of zero,
**       then indent all opcodes between the earlier instruction
**       and "Goto" by 2 spaces.
*/
static void explain_data_prepare(struct callback_data *p, sqlite3_stmt *pSql){
  const char *zSql;               /* The text of the SQL statement */
  const char *z;                  /* Used to check if this is an EXPLAIN */
  int *abYield = 0;               /* True if op is an OP_Yield */

    abYield[iOp] = str_in_array(zOp, azYield);
    p->aiIndent[iOp] = 0;
    p->nIndent = iOp+1;

    if( str_in_array(zOp, azNext) ){
      for(i=p2op; i<iOp; i++) p->aiIndent[i] += 2;
    }
    if( str_in_array(zOp, azGoto) && p2op<p->nIndent
     && (abYield[p2op] || sqlite3_column_int(pSql, 2))
    ){
      for(i=p2op+1; i<iOp; i++) p->aiIndent[i] += 2;
    }
  }

  p->iIndent = 0;
  sqlite3_free(abYield);
  sqlite3_reset(pSql);

      printf(
        "SQLite version %s %.19s\n" /*extra-version-info*/
        "Enter \".help\" for usage hints.\n",
        sqlite3_libversion(), sqlite3_sourceid()
      );
      if( warnInmemoryDb ){
        printf("Connected to a ");
        printBold("transient in-memory database");
        printf(".\nUse \".open FILENAME\" to reopen on a "
               "persistent database.\n");
      }
      zHome = find_home_dir();
      if( zHome ){
        nHistory = strlen30(zHome) + 20;
        if( (zHistory = malloc(nHistory))!=0 ){
          sqlite3_snprintf(nHistory, zHistory,"%s/.sqlite_history", zHome);

# define _LARGE_FILE       1
# ifndef _FILE_OFFSET_BITS
#   define _FILE_OFFSET_BITS 64
# endif
# define _LARGEFILE_SOURCE 1
#endif

/*
** For MinGW, check to see if we can include the header file containing its
** version information, among other things.  Normally, this internal MinGW
** header file would [only] be included automatically by other MinGW header
** files; however, the contained version information is now required by this
** header file to work around binary compatibility issues (see below) and
** this is the only known way to reliably obtain it.  This entire #if block
** would be completely unnecessary if there was any other way of detecting
** MinGW via their preprocessor (e.g. if they customized their GCC to define
** some MinGW-specific macros).  When compiling for MinGW, either the
** _HAVE_MINGW_H or _HAVE__MINGW_H (note the extra underscore) macro must be
** defined; otherwise, detection of conditions specific to MinGW will be
** disabled.
*/
#if defined(_HAVE_MINGW_H)
# include "mingw.h"
#elif defined(_HAVE__MINGW_H)
# include "_mingw.h"
#endif

/*
** For MinGW version 4.x (and higher), check to see if the _USE_32BIT_TIME_T
** define is required to maintain binary compatibility with the MSVC runtime
** library in use (e.g. for Windows XP).
*/
#if !defined(_USE_32BIT_TIME_T) && !defined(_USE_64BIT_TIME_T) && \
    defined(_WIN32) && !defined(_WIN64) && \
    defined(__MINGW_MAJOR_VERSION) && __MINGW_MAJOR_VERSION >= 4 && \
    defined(__MSVCRT__)
# define _USE_32BIT_TIME_T
#endif

/* The public SQLite interface.  The _FILE_OFFSET_BITS macro must appear
** first in QNX.  Also, the _USE_32BIT_TIME_T macro must appear first for
** MinGW.
*/
#include "sqlite3.h"

/*
** Include the configuration header output by 'configure' if we're using the
** autoconf-based build
*/

/*
** Invoke this macro on memory cells just prior to changing the
** value of the cell.  This macro verifies that shallow copies are
** not misused.  A shallow copy of a string or blob just copies a
** pointer to the string or blob, not the content.  If the original
** is changed while the copy is still in use, the string or blob might
** be changed out from under the copy.  This macro verifies that nothing
** like that ever happens.
*/
#ifdef SQLITE_DEBUG
# define memAboutToChange(P,M) sqlite3VdbeMemAboutToChange(P,M)
#else
# define memAboutToChange(P,M)
#endif

/* Opcode:  Goto * P2 * * *
**
** An unconditional jump to address P2.
** The next instruction executed will be 
** the one at index P2 from the beginning of
** the program.
**
** The P1 parameter is not actually used by this opcode.  However, it
** is sometimes set to 1 instead of 0 as a hint to the command-line shell
** that this Goto is the bottom of a loop and that the lines from P2 down
** to the current line should be indented for EXPLAIN output.
*/
case OP_Goto: {             /* jump */
  pc = pOp->p2 - 1;

  /* Opcodes that are used as the bottom of a loop (OP_Next, OP_Prev,
  ** OP_VNext, OP_RowSetNext, or OP_SorterNext) all jump here upon
  ** completion.  Check to see if sqlite3_interrupt() has been called

  break;
}

/* Opcode: Once P1 P2 * * *
**
** Check if OP_Once flag P1 is set. If so, jump to instruction P2. Otherwise,
** set the flag and fall through to the next instruction.  In other words,
** this opcode causes all following opcodes up through P2 (but not including
** P2) to run just once and to be skipped on subsequent times through the loop.
*/
case OP_Once: {             /* jump */
  assert( pOp->p1<p->nOnceFlag );
  VdbeBranchTaken(p->aOnceFlag[pOp->p1]!=0, 2);
  if( p->aOnceFlag[pOp->p1] ){
    pc = pOp->p2-1;
  }else{

      ** callgrind, this causes a certain test case to hit the CPU 4.7 
      ** percent less (x86 linux, gcc version 4.1.2, -O6) than if 
      ** sqlite3MemRelease() were called from here. With -O2, this jumps
      ** to 6.6 percent. The test case is inserting 1000 rows into a table 
      ** with no indexes using a single prepared INSERT statement, bind() 
      ** and reset(). Inserts are grouped into a transaction.
      */
      testcase( p->flags & MEM_Agg );
      testcase( p->flags & MEM_Dyn );
      testcase( p->flags & MEM_Frame );
      testcase( p->flags & MEM_RowSet );
      if( p->flags&(MEM_Agg|MEM_Dyn|MEM_Frame|MEM_RowSet) ){
        sqlite3VdbeMemRelease(p);
      }else if( p->zMalloc ){
        sqlite3DbFree(db, p->zMalloc);
        p->zMalloc = 0;
      }

    case 0: {  /* NULL */
      pMem->flags = MEM_Null;
      break;
    }
    case 1: { /* 1-byte signed integer */
      pMem->u.i = ONE_BYTE_INT(buf);
      pMem->flags = MEM_Int;
      testcase( pMem->u.i<0 );
      return 1;
    }
    case 2: { /* 2-byte signed integer */
      pMem->u.i = TWO_BYTE_INT(buf);
      pMem->flags = MEM_Int;
      testcase( pMem->u.i<0 );
      return 2;
    }
    case 3: { /* 3-byte signed integer */
      pMem->u.i = THREE_BYTE_INT(buf);
      pMem->flags = MEM_Int;
      testcase( pMem->u.i<0 );
      return 3;
    }
    case 4: { /* 4-byte signed integer */
      y = FOUR_BYTE_UINT(buf);
      pMem->u.i = (i64)*(int*)&y;
      pMem->flags = MEM_Int;
      testcase( pMem->u.i<0 );
      return 4;
    }
    case 5: { /* 6-byte signed integer */
      pMem->u.i = FOUR_BYTE_UINT(buf+2) + (((i64)1)<<32)*TWO_BYTE_INT(buf);
      pMem->flags = MEM_Int;
      testcase( pMem->u.i<0 );
      return 6;
    }
    case 6:   /* 8-byte signed integer */
    case 7: { /* IEEE floating point */
#if !defined(NDEBUG) && !defined(SQLITE_OMIT_FLOATING_POINT)
      /* Verify that integers and floating point values use the same
      ** byte order.  Or, that if SQLITE_MIXED_ENDIAN_64BIT_FLOAT is

#endif
      x = FOUR_BYTE_UINT(buf);
      y = FOUR_BYTE_UINT(buf+4);
      x = (x<<32) | y;
      if( serial_type==6 ){
        pMem->u.i = *(i64*)&x;
        pMem->flags = MEM_Int;
        testcase( pMem->u.i<0 );
      }else{
        assert( sizeof(x)==8 && sizeof(pMem->r)==8 );
        swapMixedEndianFloat(x);
        memcpy(&pMem->r, &x, sizeof(x));
        pMem->flags = sqlite3IsNaN(pMem->r) ? MEM_Null : MEM_Real;
      }
      return 8;

*/
static i64 vdbeRecordDecodeInt(u32 serial_type, const u8 *aKey){
  u32 y;
  assert( CORRUPT_DB || (serial_type>=1 && serial_type<=9 && serial_type!=7) );
  switch( serial_type ){
    case 0:
    case 1:
      testcase( aKey[0]&0x80 );
      return ONE_BYTE_INT(aKey);
    case 2:
      testcase( aKey[0]&0x80 );
      return TWO_BYTE_INT(aKey);
    case 3:
      testcase( aKey[0]&0x80 );
      return THREE_BYTE_INT(aKey);
    case 4: {
      testcase( aKey[0]&0x80 );
      y = FOUR_BYTE_UINT(aKey);
      return (i64)*(int*)&y;
    }
    case 5: {
      testcase( aKey[0]&0x80 );
      return FOUR_BYTE_UINT(aKey+2) + (((i64)1)<<32)*TWO_BYTE_INT(aKey);
    }
    case 6: {
      u64 x = FOUR_BYTE_UINT(aKey);
      testcase( aKey[0]&0x80 );
      x = (x<<32) | FOUR_BYTE_UINT(aKey+4);
      return (i64)*(i64*)&x;
    }
  }

  return (serial_type - 8);
}

  assert( idx1<=szHdr1 || CORRUPT_DB );
  do{
    u32 serial_type;

    /* RHS is an integer */
    if( pRhs->flags & MEM_Int ){
      serial_type = aKey1[idx1];
      testcase( serial_type==12 );
      if( serial_type>=12 ){
        rc = +1;
      }else if( serial_type==0 ){
        rc = -1;
      }else if( serial_type==7 ){
        double rhs = (double)pRhs->u.i;
        sqlite3VdbeSerialGet(&aKey1[d1], serial_type, &mem1);

        }
      }
    }

    /* RHS is a string */
    else if( pRhs->flags & MEM_Str ){
      getVarint32(&aKey1[idx1], serial_type);
      testcase( serial_type==12 );
      if( serial_type<12 ){
        rc = -1;
      }else if( !(serial_type & 0x01) ){
        rc = +1;
      }else{
        mem1.n = (serial_type - 12) / 2;
        testcase( (d1+mem1.n)==(unsigned)nKey1 );
        testcase( (d1+mem1.n+1)==(unsigned)nKey1 );
        if( (d1+mem1.n) > (unsigned)nKey1 ){
          rc = 1;                /* Corruption */
        }else if( pKeyInfo->aColl[i] ){
          mem1.enc = pKeyInfo->enc;
          mem1.db = pKeyInfo->db;
          mem1.flags = MEM_Str;
          mem1.z = (char*)&aKey1[d1];
          rc = vdbeCompareMemString(&mem1, pRhs, pKeyInfo->aColl[i]);
        }else{
          int nCmp = MIN(mem1.n, pRhs->n);
          rc = memcmp(&aKey1[d1], pRhs->z, nCmp);
          if( rc==0 ) rc = mem1.n - pRhs->n; 
        }
      }
    }

    /* RHS is a blob */
    else if( pRhs->flags & MEM_Blob ){
      getVarint32(&aKey1[idx1], serial_type);
      testcase( serial_type==12 );
      if( serial_type<12 || (serial_type & 0x01) ){
        rc = -1;
      }else{
        int nStr = (serial_type - 12) / 2;
        testcase( (d1+nStr)==(unsigned)nKey1 );
        testcase( (d1+nStr+1)==(unsigned)nKey1 );
        if( (d1+nStr) > (unsigned)nKey1 ){
          rc = 1;                /* Corruption */
        }else{
          int nCmp = MIN(nStr, pRhs->n);
          rc = memcmp(&aKey1[d1], pRhs->z, nCmp);
          if( rc==0 ) rc = nStr - pRhs->n;
        }

  i64 lhs;
  UNUSED_PARAMETER(bSkip);

  assert( bSkip==0 );
  switch( serial_type ){
    case 1: { /* 1-byte signed integer */
      lhs = ONE_BYTE_INT(aKey);
      testcase( lhs<0 );
      break;
    }
    case 2: { /* 2-byte signed integer */
      lhs = TWO_BYTE_INT(aKey);
      testcase( lhs<0 );
      break;
    }
    case 3: { /* 3-byte signed integer */
      lhs = THREE_BYTE_INT(aKey);
      testcase( lhs<0 );
      break;
    }
    case 4: { /* 4-byte signed integer */
      y = FOUR_BYTE_UINT(aKey);
      lhs = (i64)*(int*)&y;
      testcase( lhs<0 );
      break;
    }
    case 5: { /* 6-byte signed integer */
      lhs = FOUR_BYTE_UINT(aKey+2) + (((i64)1)<<32)*TWO_BYTE_INT(aKey);
      testcase( lhs<0 );
      break;
    }
    case 6: { /* 8-byte signed integer */
      x = FOUR_BYTE_UINT(aKey);
      x = (x<<32) | FOUR_BYTE_UINT(aKey+4);
      lhs = *(i64*)&x;
      testcase( lhs<0 );
      break;
    }
    case 8: 
      lhs = 0;
      break;
    case 9:
      lhs = 1;

    }else{
      p->r1 = -1;
      p->r2 = 1;
    }
    if( (flags & MEM_Int) ){
      return vdbeRecordCompareInt;
    }
    testcase( flags & MEM_Real );
    testcase( flags & MEM_Null );
    testcase( flags & MEM_Blob );
    if( (flags & (MEM_Real|MEM_Null|MEM_Blob))==0 && p->pKeyInfo->aColl[0]==0 ){

      assert( flags & MEM_Str );
      return vdbeRecordCompareString;
    }
  }

  return sqlite3VdbeRecordCompare;
}

      pRangeStart = pLoop->aLTerm[j++];
      nExtraReg = 1;
    }
    if( pLoop->wsFlags & WHERE_TOP_LIMIT ){
      pRangeEnd = pLoop->aLTerm[j++];
      nExtraReg = 1;
      if( pRangeStart==0

       && (j = pIdx->aiColumn[nEq])>=0 
       && pIdx->pTable->aCol[j].notNull==0
      ){
        bSeekPastNull = 1;
      }
    }
    assert( pRangeEnd==0 || (pRangeEnd->wtFlags & TERM_VNULL)==0 );

    /* Generate code to evaluate all constraint terms using == or IN
    ** and store the values of those terms in an array of registers
    ** starting at regBase.
    */
    regBase = codeAllEqualityTerms(pParse,pLevel,bRev,nExtraReg,&zStartAff);
    assert( zStartAff==0 || sqlite3Strlen30(zStartAff)>=nEq );