transmission/libtransmission/bitfield.h

110 lines
2.5 KiB
C

/*
* 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)
* 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 <assert.h>
#include "transmission.h"
/** @brief Implementation of the BitTorrent spec's Bitfield array of bits */
typedef struct tr_bitfield
{
uint8_t * bits;
size_t alloc_count;
size_t bit_count;
size_t true_count;
/* Special cases for when full or empty but we don't know the bitCount.
This occurs when a magnet link's peers send have all / have none */
bool have_all_hint;
bool have_none_hint;
}
tr_bitfield;
/***
****
***/
void tr_bitfieldSetHasAll( tr_bitfield* );
void tr_bitfieldSetHasNone( tr_bitfield* );
void tr_bitfieldAdd( tr_bitfield*, size_t bit );
void tr_bitfieldRem( tr_bitfield*, size_t bit );
void tr_bitfieldAddRange( tr_bitfield*, size_t begin, size_t end );
void tr_bitfieldRemRange( tr_bitfield*, size_t begin, size_t end );
/***
**** life cycle
***/
extern const tr_bitfield TR_BITFIELD_INIT;
void tr_bitfieldConstruct( tr_bitfield*, size_t bit_count );
static inline void
tr_bitfieldDestruct( tr_bitfield * b )
{
tr_bitfieldSetHasNone( b );
}
/***
****
***/
void tr_bitfieldSetFromBitfield( tr_bitfield*, const tr_bitfield* );
void tr_bitfieldSetRaw( tr_bitfield*, const void * bits, size_t byte_count );
void* tr_bitfieldGetRaw( const tr_bitfield * b, size_t * byte_count );
/***
****
***/
size_t tr_bitfieldCountRange( const tr_bitfield*, size_t begin, size_t end );
size_t tr_bitfieldCountTrueBits( const tr_bitfield * b );
static inline bool
tr_bitfieldHasAll( const tr_bitfield * b )
{
return b->bit_count ? ( b->true_count == b->bit_count ) : b->have_all_hint;
}
static inline bool
tr_bitfieldHasNone( const tr_bitfield * b )
{
return b->bit_count ? ( b->true_count == 0 ) : b->have_none_hint;
}
static inline bool
tr_bitfieldHas( const tr_bitfield * b, size_t n )
{
if( tr_bitfieldHasAll( b ) ) return true;
if( tr_bitfieldHasNone( b ) ) return false;
if( n>>3u >= b->alloc_count ) return false;
return ( b->bits[n>>3u] << ( n & 7u ) & 0x80 ) != 0;
}
#endif