Danny Robson
c2265b9ed2
sometimes we need to ensure memory allocation has a particular alignment in an _offset_ buffer (which we have no control over, eg renderdoc's OpenGL buffers). this applies an offset to various operations that make the aligned::direct allocator correctly align allocations for buffers that aren't themselves aligned.
162 lines
3.4 KiB
C++
162 lines
3.4 KiB
C++
/*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* Copyright 2015 Danny Robson <danny@nerdcruft.net>
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*/
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#include "linear.hpp"
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#include "../../pointer.hpp"
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#include "../../debug.hpp"
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using util::alloc::raw::linear;
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///////////////////////////////////////////////////////////////////////////////
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linear::linear (util::view<std::byte*> _data):
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m_begin (_data.begin ()),
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m_end (_data.end ()),
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m_cursor (_data.begin ())
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{ ; }
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///////////////////////////////////////////////////////////////////////////////
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void*
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linear::allocate (size_t bytes)
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{
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return allocate (bytes, alignof (std::max_align_t));
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}
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//-----------------------------------------------------------------------------
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void*
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linear::allocate (size_t bytes, size_t alignment)
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{
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auto ptr = align (m_cursor, alignment);
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if (ptr + bytes > m_end)
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throw std::bad_alloc ();
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m_cursor = ptr + bytes;
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return ptr;
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}
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//-----------------------------------------------------------------------------
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void
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linear::deallocate (void *ptr, size_t bytes)
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{
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deallocate (ptr, bytes, alignof (std::max_align_t));
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}
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//-----------------------------------------------------------------------------
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void
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linear::deallocate (void *ptr, size_t bytes, size_t alignment)
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{
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(void)ptr;
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(void)bytes;
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(void)alignment;
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}
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//-----------------------------------------------------------------------------
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std::byte*
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linear::data (void)
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{
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return m_begin;
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}
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//-----------------------------------------------------------------------------
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const std::byte*
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linear::data (void) const
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{
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return m_begin;
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}
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//-----------------------------------------------------------------------------
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std::byte*
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linear::begin (void)
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{
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return m_begin;
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}
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//-----------------------------------------------------------------------------
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const std::byte*
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linear::begin (void) const
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{
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return m_begin;
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}
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//-----------------------------------------------------------------------------
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std::byte*
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linear::end (void)
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{
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return m_end;
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}
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//-----------------------------------------------------------------------------
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const std::byte*
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linear::end (void) const
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{
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return m_end;
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}
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//-----------------------------------------------------------------------------
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size_t
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linear::offset (const void *_ptr) const
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{
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auto ptr = reinterpret_cast<const std::byte*> (_ptr);
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CHECK_GE (ptr, m_begin);
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return ptr - m_begin;
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}
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///////////////////////////////////////////////////////////////////////////////
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void
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linear::reset (void)
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{
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m_cursor = m_begin;
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}
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///////////////////////////////////////////////////////////////////////////////
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size_t
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linear::capacity (void) const
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{
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return m_end - m_begin;
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}
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//-----------------------------------------------------------------------------
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size_t
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linear::used (void) const
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{
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return m_cursor - m_begin;
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}
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//-----------------------------------------------------------------------------
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size_t
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linear::remain (void) const
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{
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return capacity () - used ();
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}
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