** Clear operations are exceedingly rare.  There are usually between
** 5 and 500 set operations per Bitvec object, though the number of sets can
** sometimes grow into tens of thousands or larger.  The size of the
** Bitvec object is the number of pages in the database file at the
** start of a transaction, and is thus usually less than a few thousand,
** but can be as large as 2 billion for a really big database.
**
** @(#) $Id: bitvec.c,v 1.13 2009/01/20 17:06:27 danielk1977 Exp $
*/
#include "sqliteInt.h"

/* Size of the Bitvec structure in bytes. */
#define BITVEC_SZ        512

/* Round the union size down to the nearest pointer boundary, since that's how 
................................................................................
** values between 1 and iDivisor.  apSub[1] holds values between
** iDivisor+1 and 2*iDivisor.  apSub[N] holds values between
** N*iDivisor+1 and (N+1)*iDivisor.  Each subbitmap is normalized
** to hold deal with values between 1 and iDivisor.
*/
struct Bitvec {
  u32 iSize;      /* Maximum bit index.  Max iSize is 4,294,967,296. */
  u32 nSet;       /* Number of bits that are set - only valid for aHash element */
                  /* Max nSet is BITVEC_NINT.  For BITVEC_SZ of 512, this would be 125. */

  u32 iDivisor;   /* Number of bits handled by each apSub[] entry. */
                  /* Should >=0 for apSub element. */
                  /* Max iDivisor is max(u32) / BITVEC_NPTR + 1.  */
                  /* For a BITVEC_SZ of 512, this would be 34,359,739. */
  union {
    BITVEC_TELEM aBitmap[BITVEC_NELEM];    /* Bitmap representation */
    u32 aHash[BITVEC_NINT];      /* Hash table representation */
................................................................................

  /* Test to make sure the linear array exactly matches the
  ** Bitvec object.  Start with the assumption that they do
  ** match (rc==0).  Change rc to non-zero if a discrepancy
  ** is found.
  */
  rc = sqlite3BitvecTest(0,0) + sqlite3BitvecTest(pBitvec, sz+1)
          + sqlite3BitvecTest(pBitvec, 0);

  for(i=1; i<=sz; i++){
    if(  (TESTBIT(pV,i))!=sqlite3BitvecTest(pBitvec,i) ){
      rc = i;
      break;
    }
  }

** Clear operations are exceedingly rare.  There are usually between
** 5 and 500 set operations per Bitvec object, though the number of sets can
** sometimes grow into tens of thousands or larger.  The size of the
** Bitvec object is the number of pages in the database file at the
** start of a transaction, and is thus usually less than a few thousand,
** but can be as large as 2 billion for a really big database.
**
** @(#) $Id: bitvec.c,v 1.14 2009/04/01 23:49:04 drh Exp $
*/
#include "sqliteInt.h"

/* Size of the Bitvec structure in bytes. */
#define BITVEC_SZ        512

/* Round the union size down to the nearest pointer boundary, since that's how 
................................................................................
** values between 1 and iDivisor.  apSub[1] holds values between
** iDivisor+1 and 2*iDivisor.  apSub[N] holds values between
** N*iDivisor+1 and (N+1)*iDivisor.  Each subbitmap is normalized
** to hold deal with values between 1 and iDivisor.
*/
struct Bitvec {
  u32 iSize;      /* Maximum bit index.  Max iSize is 4,294,967,296. */
  u32 nSet;       /* Number of bits that are set - only valid for aHash
                  ** element.  Max is BITVEC_NINT.  For BITVEC_SZ of 512,
                  ** this would be 125. */
  u32 iDivisor;   /* Number of bits handled by each apSub[] entry. */
                  /* Should >=0 for apSub element. */
                  /* Max iDivisor is max(u32) / BITVEC_NPTR + 1.  */
                  /* For a BITVEC_SZ of 512, this would be 34,359,739. */
  union {
    BITVEC_TELEM aBitmap[BITVEC_NELEM];    /* Bitmap representation */
    u32 aHash[BITVEC_NINT];      /* Hash table representation */
................................................................................

  /* Test to make sure the linear array exactly matches the
  ** Bitvec object.  Start with the assumption that they do
  ** match (rc==0).  Change rc to non-zero if a discrepancy
  ** is found.
  */
  rc = sqlite3BitvecTest(0,0) + sqlite3BitvecTest(pBitvec, sz+1)
          + sqlite3BitvecTest(pBitvec, 0)
          + (sqlite3BitvecSize(pBitvec) - sz);
  for(i=1; i<=sz; i++){
    if(  (TESTBIT(pV,i))!=sqlite3BitvecTest(pBitvec,i) ){
      rc = i;
      break;
    }
  }

#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
#
# Unit testing of the Bitvec object.
#
# $Id: bitvec.test,v 1.3 2008/11/19 18:30:35 shane Exp $
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl

# The built-in test logic must be operational in order for
# this test to work.
................................................................................
  sqlite3BitvecBuiltinTest 4000 {3 10 2 4000 1 1 0}
} 0
do_test bitvec-2.5 {
  sqlite3BitvecBuiltinTest 5000 {3 20 2 5000 1 1 0}
} 0
do_test bitvec-2.6 {
  sqlite3BitvecBuiltinTest 50000 {3 60 2 50000 1 1 0}








} 0

# This procedure runs sqlite3BitvecBuiltinTest with argments "n" and
# "program".  But it also causes a malloc error to occur after the
# "failcnt"-th malloc.  The result should be "0" if no malloc failure
# occurs or "-1" if there is a malloc failure.
#

#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
#
# Unit testing of the Bitvec object.
#
# $Id: bitvec.test,v 1.4 2009/04/01 23:49:04 drh Exp $
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl

# The built-in test logic must be operational in order for
# this test to work.
................................................................................
  sqlite3BitvecBuiltinTest 4000 {3 10 2 4000 1 1 0}
} 0
do_test bitvec-2.5 {
  sqlite3BitvecBuiltinTest 5000 {3 20 2 5000 1 1 0}
} 0
do_test bitvec-2.6 {
  sqlite3BitvecBuiltinTest 50000 {3 60 2 50000 1 1 0}
} 0
do_test bitvec-2.7 {
  sqlite3BitvecBuiltinTest 5000 {
          1 25 121 125
          1 50 121 125
          2 25 121 125
          0
  }
} 0

# This procedure runs sqlite3BitvecBuiltinTest with argments "n" and
# "program".  But it also causes a malloc error to occur after the
# "failcnt"-th malloc.  The result should be "0" if no malloc failure
# occurs or "-1" if there is a malloc failure.
#