/*
 * 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: bitfield.h 13655 2012-12-13 02:00:45Z jordan $
 */

#ifndef __TRANSMISSION__
 #error only libtransmission should #include this header.
#endif

#ifndef TR_BITFIELD_H
#define TR_BITFIELD_H 1

#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_bitfieldSetFromFlags (tr_bitfield*, const bool * bytes, size_t n);

void   tr_bitfieldSetFromBitfield (tr_bitfield*, const tr_bitfield*);

void   tr_bitfieldSetRaw (tr_bitfield*, const void * bits, size_t byte_count, bool bounded);

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;
}

bool tr_bitfieldHas (const tr_bitfield * b, size_t n);

#endif
