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construct/include/ircd/allocator/state.h

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// Matrix Construct
//
// Copyright (C) Matrix Construct Developers, Authors & Contributors
// Copyright (C) 2016-2023 Jason Volk <jason@zemos.net>
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice is present in all copies. The
// full license for this software is available in the LICENSE file.
#pragma once
#define HAVE_IRCD_ALLOCATOR_STATE_H
namespace ircd::allocator
{
struct state;
}
struct ircd::allocator::state
{
using word_t = unsigned long long;
using size_type = std::size_t;
size_t size { 0 };
word_t *avail { nullptr };
size_t last { 0 };
static uint byte(const uint &i) { return i / (sizeof(word_t) * 8); }
static uint bit(const uint &i) { return i % (sizeof(word_t) * 8); }
static word_t mask(const uint &pos) { return word_t(1) << bit(pos); }
bool test(const uint &pos) const { return avail[byte(pos)] & mask(pos); }
void bts(const uint &pos) { avail[byte(pos)] |= mask(pos); }
void btc(const uint &pos) { avail[byte(pos)] &= ~mask(pos); }
uint next(const size_t &n) const;
public:
bool available(const size_t &n = 1) const;
void deallocate(const uint &p, const size_t &n);
uint allocate(std::nothrow_t, const size_t &n, const uint &hint = -1);
uint allocate(const size_t &n, const uint &hint = -1);
state(const size_t &size = 0,
word_t *const &avail = nullptr)
:size{size}
,avail{avail}
,last{0}
{}
};