SQLite

#define testcase(x)
#define ALWAYS(x) 1
#define NEVER(x) 0

#define MIN(x,y) (((x) < (y)) ? (x) : (y))
#define MAX(x,y) (((x) > (y)) ? (x) : (y))

/*
** Constants for the largest and smallest possible 64-bit signed integers.
*/
# define LARGEST_INT64  (0xffffffff|(((i64)0x7fffffff)<<32))
# define SMALLEST_INT64 (((i64)-1) - LARGEST_INT64)

#endif


/*
** Maximum number of prefix indexes on single FTS5 table. This must be
** less than 32. If it is set to anything large than that, an #error
** directive in fts5_index.c will cause the build to fail.

  Fts5Structure *pStruct;         /* Database structure for this iterator */
  Fts5Buffer poslist;             /* Buffer containing current poslist */

  int nSeg;                       /* Size of aSeg[] array */
  int bRev;                       /* True to iterate in reverse order */
  int bSkipEmpty;                 /* True to skip deleted entries */
  int bEof;                       /* True at EOF */

  i64 iSwitchRowid;               /* Firstest rowid of other than aFirst[1] */
  Fts5CResult *aFirst;            /* Current merge state (see above) */
  Fts5SegIter aSeg[1];            /* Array of segment iterators */
};


/*
** Object for iterating through the conents of a single internal node in 

** This function is a no-op unless SQLITE_DEBUG is defined when this module
** is compiled. In that case, this function is essentially an assert() 
** statement used to verify that the contents of the pIter->aFirst[] array
** are correct.
*/
static void fts5AssertMultiIterSetup(Fts5Index *p, Fts5IndexIter *pIter){
  if( p->rc==SQLITE_OK ){
    Fts5SegIter *pFirst = &pIter->aSeg[ pIter->aFirst[1].iFirst ];
    int i;

    assert( (pFirst->pLeaf==0)==pIter->bEof );

    /* Check that pIter->iSwitchRowid is set correctly. */
    for(i=0; i<pIter->nSeg; i++){
      Fts5SegIter *p1 = &pIter->aSeg[i];
      assert( p1==pFirst 
           || p1->pLeaf==0 
           || fts5BufferCompare(&pFirst->term, &p1->term) 
           || p1->iRowid==pIter->iSwitchRowid
           || (p1->iRowid<pIter->iSwitchRowid)==pIter->bRev
      );
    }

    for(i=0; i<pIter->nSeg; i+=2){
      Fts5SegIter *p1 = &pIter->aSeg[i];
      Fts5SegIter *p2 = &pIter->aSeg[i+1];
      Fts5CResult *pRes = &pIter->aFirst[(pIter->nSeg + i) / 2];
      fts5AssertComparisonResult(pIter, p1, p2, pRes);
    }

** that it deals with more complicated cases as well.
*/ 
static int fts5MultiIterAdvanceRowid(
  Fts5Index *p,                   /* FTS5 backend to iterate within */
  Fts5IndexIter *pIter,           /* Iterator to update aFirst[] array for */
  int iChanged                    /* Index of sub-iterator just advanced */
){

  Fts5SegIter *pNew = &pIter->aSeg[iChanged];

  if( pNew->iRowid==pIter->iSwitchRowid
   || (pNew->iRowid<pIter->iSwitchRowid)==pIter->bRev
  ){
    int i;
    Fts5SegIter *pOther = &pIter->aSeg[iChanged ^ 0x0001];
    pIter->iSwitchRowid = pIter->bRev ? SMALLEST_INT64 : LARGEST_INT64;
    for(i=(pIter->nSeg+iChanged)/2; 1; i=i/2){
      Fts5CResult *pRes = &pIter->aFirst[i];

      assert( pNew->pLeaf );
      assert( pRes->bTermEq==0 || pOther->pLeaf );

      if( pRes->bTermEq ){
        if( pNew->iRowid==pOther->iRowid ){
          return 1;
        }else if( (pOther->iRowid>pNew->iRowid)==pIter->bRev ){
          pIter->iSwitchRowid = pOther->iRowid;
          pNew = pOther;
        }else if( (pOther->iRowid>pIter->iSwitchRowid)==pIter->bRev ){
          pIter->iSwitchRowid = pOther->iRowid;
        }
      }
      pRes->iFirst = (pNew - pIter->aSeg);
      if( i==1 ) break;

      pOther = &pIter->aSeg[ pIter->aFirst[i ^ 0x0001].iFirst ];
    }
  }

  return 0;
}

/*
** Set the pIter->bEof variable based on the state of the sub-iterators.
*/
static void fts5MultiIterSetEof(Fts5IndexIter *pIter){
  Fts5SegIter *pSeg = &pIter->aSeg[ pIter->aFirst[1].iFirst ];
  pIter->bEof = pSeg->pLeaf==0;
  pIter->iSwitchRowid = pSeg->iRowid;
}

/*
** Move the iterator to the next entry. 
**
** If an error occurs, an error code is left in Fts5Index.rc. It is not 
** considered an error if the iterator reaches EOF, or if it is already at 

#define FTS5CSR_EOF               0x08
#define FTS5CSR_FREE_ZRANK        0x10
#define FTS5CSR_REQUIRE_RESEEK    0x20

#define BitFlagAllTest(x,y) (((x) & (y))==(y))
#define BitFlagTest(x,y)    (((x) & (y))!=0)










/*
** Macros to Set(), Clear() and Test() cursor flags.
*/
#define CsrFlagSet(pCsr, flag)   ((pCsr)->csrflags |= (flag))
#define CsrFlagClear(pCsr, flag) ((pCsr)->csrflags &= ~(flag))
#define CsrFlagTest(pCsr, flag)  ((pCsr)->csrflags & (flag))