libcruft-util/alloc/raw/linear.cpp

135 lines
3.0 KiB
C++

/*
* 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 Danny Robson <danny@nerdcruft.net>
*/
#include "linear.hpp"
#include "../../pointer.hpp"
#include "../../debug.hpp"
using util::alloc::raw::linear;
///////////////////////////////////////////////////////////////////////////////
linear::linear (void *begin, void *end):
m_begin (reinterpret_cast<char*> (begin)),
m_end (reinterpret_cast<char*> (end)),
m_cursor (reinterpret_cast<char*> (begin))
{
CHECK_NEZ (begin);
CHECK_NEZ (end);
CHECK_LE (begin, end);
}
///////////////////////////////////////////////////////////////////////////////
void*
linear::allocate (size_t bytes)
{
return allocate (bytes, alignof (std::max_align_t));
}
//-----------------------------------------------------------------------------
void*
linear::allocate (size_t bytes, size_t alignment)
{
auto ptr = align (m_cursor, alignment);
if (ptr + bytes > m_end)
throw std::bad_alloc ();
m_cursor = ptr + bytes;
CHECK_NEZ (ptr);
return ptr;
}
//-----------------------------------------------------------------------------
void
linear::deallocate (void *ptr, size_t bytes)
{
deallocate (ptr, bytes, alignof (std::max_align_t));
}
//-----------------------------------------------------------------------------
void
linear::deallocate (void *ptr, size_t bytes, size_t alignment)
{
(void)ptr;
(void)bytes;
(void)alignment;
}
//-----------------------------------------------------------------------------
void*
linear::begin (void)
{
return m_begin;
}
//-----------------------------------------------------------------------------
const void*
linear::begin (void) const
{
return m_begin;
}
//-----------------------------------------------------------------------------
size_t
linear::offset (const void *_ptr) const
{
auto ptr = reinterpret_cast<const char*> (_ptr);
CHECK_GE (ptr, m_begin);
return ptr - m_begin;
}
///////////////////////////////////////////////////////////////////////////////
void
linear::reset (void)
{
m_cursor = m_begin;
}
///////////////////////////////////////////////////////////////////////////////
size_t
linear::capacity (void) const
{
return m_end - m_begin;
}
//-----------------------------------------------------------------------------
size_t
linear::used (void) const
{
return m_cursor - m_begin;
}
//-----------------------------------------------------------------------------
size_t
linear::remain (void) const
{
return capacity () - used ();
}