libcruft-util/alloc/raw/stack.cpp

/*
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * Copyright 2015-2016 Danny Robson <danny@nerdcruft.net>
 */

#include "stack.hpp"

#include "../../debug.hpp"
#include "../../pointer.hpp"
#include "../../cast.hpp"

using util::alloc::raw::stack;


///////////////////////////////////////////////////////////////////////////////
stack::stack (util::view<std::byte*> _data):
    m_begin  (_data.begin ()),
    m_end    (_data.end ()),
    m_cursor (m_begin)
{
    CHECK_LE (m_begin, m_end);
}


//-----------------------------------------------------------------------------
std::byte*
stack::begin (void)
{
    return m_begin;
}


//-----------------------------------------------------------------------------
const std::byte*
stack::begin (void) const
{
    return m_begin;
}


//-----------------------------------------------------------------------------
size_t
stack::offset (const void *_ptr) const
{
    auto ptr = reinterpret_cast<const std::byte*> (_ptr);

    CHECK_GE (ptr, m_begin);
    return ptr - m_begin;
}


//-----------------------------------------------------------------------------
void
stack::reset (void)
{
    m_cursor = m_begin;
}


///////////////////////////////////////////////////////////////////////////////
size_t
stack::capacity (void) const
{
    return m_end - m_begin;
}


//-----------------------------------------------------------------------------
size_t
stack::used (void) const
{
    return m_cursor - m_begin;
}


//-----------------------------------------------------------------------------
size_t
stack::remain (void) const
{
    return capacity () - used ();
}