SQLite

** Prepare a crude estimate of the logarithm of the input value.
** The results need not be exact.  This is only used for estimating
** the total cost of performing operations with O(logN) or O(NlogN)
** complexity.  Because N is just a guess, it is no great tragedy if
** logN is a little off.
*/
static WhereCost estLog(WhereCost N){
  WhereCost logN = 1;
  WhereCost x = 10;
  while( N>x ){
    logN += 1;
  u32 a;
  assert( sizeof(WhereCost)==4 );  /* 32-bit float input */
  if( N<=0.0 ) return 0.0;
  memcpy(&a, &N, 4);
    x *= 10;
  }
  return logN;
  return ((a >>= 23)-127)*0.3;
}

/*
** Two routines for printing the content of an sqlite3_index_info
** structure.  Used for testing and debugging only.  If neither
** SQLITE_TEST or SQLITE_DEBUG are defined, then these routines
** are no-ops.

  if( pDistinct && isDistinctRedundant(pParse,pTabList,&pWInfo->sWC,pDistinct) ){
    pDistinct = 0;
    pWInfo->eDistinct = WHERE_DISTINCT_UNIQUE;
  }

  /* Construct the WhereLoop objects */
  WHERETRACE(("*** Optimizer Start ***\n"));
  /* TBD: if( nTablist==1 ) whereCommonCase(&sWLB); */
  rc = whereLoopAddAll(&sWLB);
  if( rc ) goto whereBeginError;

  /* Display all of the WhereLoop objects if wheretrace is enabled */
#ifdef WHERETRACE_ENABLED
  if( sqlite3WhereTrace ){
    WhereLoop *p;