transmission/libtransmission/bitfield.c

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/*
* This file Copyright (C) 2009 Charles Kerr <charles@transmissionbt.com>
*
* This file is licensed by the GPL version 2. Works owned by the
* Transmission project are granted a special exemption to clause 2(b)
* so that the bulk of its code can remain under the MIT license.
* This exemption does not extend to derived works not owned by
* the Transmission project.
*
* $Id: utils.c 8686 2009-06-14 01:01:46Z charles $
*/
#include <assert.h>
#include <string.h> /* memset */
#include "transmission.h"
#include "bitfield.h"
tr_bitfield*
tr_bitfieldConstruct( tr_bitfield * b, size_t bitCount )
{
b->bitCount = bitCount;
b->byteCount = ( bitCount + 7u ) / 8u;
b->bits = tr_new0( uint8_t, b->byteCount );
return b;
}
tr_bitfield*
tr_bitfieldDestruct( tr_bitfield * b )
{
if( b )
tr_free( b->bits );
return b;
}
tr_bitfield*
tr_bitfieldDup( const tr_bitfield * in )
{
tr_bitfield * ret = tr_new0( tr_bitfield, 1 );
ret->bitCount = in->bitCount;
ret->byteCount = in->byteCount;
ret->bits = tr_memdup( in->bits, in->byteCount );
return ret;
}
void
tr_bitfieldClear( tr_bitfield * bitfield )
{
memset( bitfield->bits, 0, bitfield->byteCount );
}
int
tr_bitfieldIsEmpty( const tr_bitfield * bitfield )
{
size_t i;
for( i = 0; i < bitfield->byteCount; ++i )
if( bitfield->bits[i] )
return 0;
return 1;
}
int
tr_bitfieldAdd( tr_bitfield * bitfield,
size_t nth )
{
assert( bitfield );
assert( bitfield->bits );
if( nth >= bitfield->bitCount )
return -1;
bitfield->bits[nth >> 3u] |= ( 0x80 >> ( nth & 7u ) );
return 0;
}
/* Sets bit range [begin, end) to 1 */
int
tr_bitfieldAddRange( tr_bitfield * b,
size_t begin,
size_t end )
{
size_t sb, eb;
unsigned char sm, em;
end--;
if( ( end >= b->bitCount ) || ( begin > end ) )
return -1;
sb = begin >> 3;
sm = ~( 0xff << ( 8 - ( begin & 7 ) ) );
eb = end >> 3;
em = 0xff << ( 7 - ( end & 7 ) );
if( sb == eb )
{
b->bits[sb] |= ( sm & em );
}
else
{
b->bits[sb] |= sm;
b->bits[eb] |= em;
if( ++sb < eb )
memset ( b->bits + sb, 0xff, eb - sb );
}
return 0;
}
int
tr_bitfieldRem( tr_bitfield * bitfield,
size_t nth )
{
assert( bitfield );
assert( bitfield->bits );
if( nth >= bitfield->bitCount )
return -1;
bitfield->bits[nth >> 3u] &= ( 0xff7f >> ( nth & 7u ) );
return 0;
}
/* Clears bit range [begin, end) to 0 */
int
tr_bitfieldRemRange( tr_bitfield * b,
size_t begin,
size_t end )
{
size_t sb, eb;
unsigned char sm, em;
end--;
if( ( end >= b->bitCount ) || ( begin > end ) )
return -1;
sb = begin >> 3;
sm = 0xff << ( 8 - ( begin & 7 ) );
eb = end >> 3;
em = ~( 0xff << ( 7 - ( end & 7 ) ) );
if( sb == eb )
{
b->bits[sb] &= ( sm | em );
}
else
{
b->bits[sb] &= sm;
b->bits[eb] &= em;
if( ++sb < eb )
memset ( b->bits + sb, 0, eb - sb );
}
return 0;
}
tr_bitfield*
tr_bitfieldOr( tr_bitfield * a,
const tr_bitfield * b )
{
uint8_t * ait;
const uint8_t *aend, *bit, *bend;
for( ait = a->bits, aend = ait + a->byteCount,
bit = b->bits, bend = bit + b->byteCount;
ait != aend && bit != bend; )
{
*ait++ |= *bit++;
}
return a;
}
/* set 'a' to all the flags that were in 'a' but not 'b' */
void
tr_bitfieldDifference( tr_bitfield * a,
const tr_bitfield * b )
{
uint8_t * ait;
const uint8_t *aend, *bit;
assert( a->byteCount == b->byteCount );
for( ait = a->bits, bit = b->bits, aend = ait + a->byteCount;
ait != aend; )
*ait++ &= ~( *bit++ );
}
size_t
tr_bitfieldCountTrueBits( const tr_bitfield* b )
{
size_t ret = 0;
const uint8_t * it, *end;
static const int trueBitCount[512] = {
0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4, 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7, 4, 5, 5, 6, 5, 6, 6, 7, 5, 6, 6, 7, 6, 7, 7, 8,
1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7, 4, 5, 5, 6, 5, 6, 6, 7, 5, 6, 6, 7, 6, 7, 7, 8,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7, 4, 5, 5, 6, 5, 6, 6, 7, 5, 6, 6, 7, 6, 7, 7, 8,
3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7, 4, 5, 5, 6, 5, 6, 6, 7, 5, 6, 6, 7, 6, 7, 7, 8,
4, 5, 5, 6, 5, 6, 6, 7, 5, 6, 6, 7, 6, 7, 7, 8, 5, 6, 6, 7, 6, 7, 7, 8, 6, 7, 7, 8, 7, 8, 8, 9
};
if( !b )
return 0;
for( it = b->bits, end = it + b->byteCount; it != end; ++it )
ret += trueBitCount[*it];
return ret;
}