transmission/libtransmission/bitfield.h

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/*
* This file Copyright (C) Mnemosyne LLC
*
* This file is licensed by the GPL version 2. Works owned by the
* Transmission project are granted a special exemption to clause 2(b)
2009-08-10 20:04:08 +00:00
* 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.
*
* $Id$
*/
#ifndef __TRANSMISSION__
#error only libtransmission should #include this header.
#endif
#ifndef TR_BITFIELD_H
#define TR_BITFIELD_H 1
#include "transmission.h"
#include "utils.h" /* tr_new0 */
/** @brief Implementation of the BitTorrent spec's Bitfield array of bits */
typedef struct tr_bitfield
{
uint8_t * bits;
size_t bitCount;
size_t byteCount;
}
tr_bitfield;
tr_bitfield* tr_bitfieldConstruct( tr_bitfield*, size_t bitcount );
tr_bitfield* tr_bitfieldDestruct( tr_bitfield* );
static inline tr_bitfield* tr_bitfieldNew( size_t bitcount )
{
return tr_bitfieldConstruct( tr_new0( tr_bitfield, 1 ), bitcount );
}
static inline void tr_bitfieldFree( tr_bitfield * b )
{
tr_free( tr_bitfieldDestruct( b ) );
}
tr_bitfield* tr_bitfieldDup( const tr_bitfield* ) TR_GNUC_MALLOC;
void tr_bitfieldClear( tr_bitfield* );
int tr_bitfieldAdd( tr_bitfield*, size_t bit );
int tr_bitfieldRem( tr_bitfield*, size_t bit );
int tr_bitfieldAddRange( tr_bitfield *, size_t begin, size_t end );
int tr_bitfieldRemRange( tr_bitfield*, size_t begin, size_t end );
void tr_bitfieldDifference( tr_bitfield *, const tr_bitfield * );
int tr_bitfieldIsEmpty( const tr_bitfield* );
size_t tr_bitfieldCountTrueBits( const tr_bitfield* );
tr_bitfield* tr_bitfieldOr( tr_bitfield*, const tr_bitfield* );
/** A stripped-down version of bitfieldHas to be used
for speed when you're looping quickly. This version
has none of tr_bitfieldHas()'s safety checks, so you
need to call tr_bitfieldTestFast() first before you
start looping. */
static inline tr_bool tr_bitfieldHasFast( const tr_bitfield * b, const size_t nth )
{
return ( b->bits[nth>>3u] << ( nth & 7u ) & 0x80 ) != 0;
}
/** @param high the highest nth bit you're going to access */
static inline tr_bool tr_bitfieldTestFast( const tr_bitfield * b, const size_t high )
{
return ( b != NULL )
&& ( b->bits != NULL )
&& ( high < b->bitCount );
}
static inline tr_bool tr_bitfieldHas( const tr_bitfield * b, size_t nth )
{
return tr_bitfieldTestFast( b, nth ) && tr_bitfieldHasFast( b, nth );
}
#endif