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//////////////////////////////////////////////////////////////////////////////
//
// (C) Copyright Ion Gaztanaga 2015-2015. Distributed under the Boost
// Software License, Version 1.0. (See accompanying file
// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
// See http://www.boost.org/libs/container for documentation.
//
//////////////////////////////////////////////////////////////////////////////
#define BOOST_CONTAINER_SOURCE
#include <boost/container/detail/config_begin.hpp>
#include <boost/container/detail/workaround.hpp>
#include <boost/container/pmr/monotonic_buffer_resource.hpp>
#include <boost/container/pmr/global_resource.hpp>
#include <boost/container/detail/min_max.hpp>
#include <boost/intrusive/detail/math.hpp>
#include <boost/container/throw_exception.hpp>
#include <cstddef>
namespace {
#ifdef BOOST_HAS_INTPTR_T
typedef boost::uintptr_t uintptr_type;
#else
typedef std::size_t uintptr_type;
#endif
static const std::size_t minimum_buffer_size = 2*sizeof(void*);
} //namespace {
namespace boost {
namespace container {
namespace pmr {
void monotonic_buffer_resource::increase_next_buffer()
{
m_next_buffer_size = (std::size_t(-1)/2 < m_next_buffer_size) ? std::size_t(-1) : m_next_buffer_size*2;
}
void monotonic_buffer_resource::increase_next_buffer_at_least_to(std::size_t minimum_size)
{
if(m_next_buffer_size < minimum_size){
if(bi::detail::is_pow2(minimum_size)){
m_next_buffer_size = minimum_size;
}
else if(std::size_t(-1)/2 < minimum_size){
m_next_buffer_size = minimum_size;
}
else{
m_next_buffer_size = bi::detail::ceil_pow2(minimum_size);
}
}
}
monotonic_buffer_resource::monotonic_buffer_resource(memory_resource* upstream) BOOST_NOEXCEPT
: m_memory_blocks(upstream ? *upstream : *get_default_resource())
, m_current_buffer(0)
, m_current_buffer_size(0u)
, m_next_buffer_size(initial_next_buffer_size)
{}
monotonic_buffer_resource::monotonic_buffer_resource(std::size_t initial_size, memory_resource* upstream) BOOST_NOEXCEPT
: m_memory_blocks(upstream ? *upstream : *get_default_resource())
, m_current_buffer(0)
, m_current_buffer_size(0u)
, m_next_buffer_size(minimum_buffer_size)
{ //In case initial_size is zero
this->increase_next_buffer_at_least_to(initial_size + !initial_size);
}
monotonic_buffer_resource::monotonic_buffer_resource(void* buffer, std::size_t buffer_size, memory_resource* upstream) BOOST_NOEXCEPT
: m_memory_blocks(upstream ? *upstream : *get_default_resource())
, m_current_buffer(buffer)
, m_current_buffer_size(buffer_size)
, m_next_buffer_size
(bi::detail::previous_or_equal_pow2
(boost::container::dtl::max_value(buffer_size, std::size_t(initial_next_buffer_size))))
{ this->increase_next_buffer(); }
monotonic_buffer_resource::~monotonic_buffer_resource()
{ this->release(); }
void monotonic_buffer_resource::release() BOOST_NOEXCEPT
{
m_memory_blocks.release();
m_current_buffer = 0u;
m_current_buffer_size = 0u;
m_next_buffer_size = initial_next_buffer_size;
}
memory_resource* monotonic_buffer_resource::upstream_resource() const BOOST_NOEXCEPT
{ return &m_memory_blocks.upstream_resource(); }
std::size_t monotonic_buffer_resource::remaining_storage(std::size_t alignment, std::size_t &wasted_due_to_alignment) const BOOST_NOEXCEPT
{
const uintptr_type up_alignment_minus1 = alignment - 1u;
const uintptr_type up_alignment_mask = ~up_alignment_minus1;
const uintptr_type up_addr = uintptr_type(m_current_buffer);
const uintptr_type up_aligned_addr = (up_addr + up_alignment_minus1) & up_alignment_mask;
wasted_due_to_alignment = std::size_t(up_aligned_addr - up_addr);
return m_current_buffer_size <= wasted_due_to_alignment ? 0u : m_current_buffer_size - wasted_due_to_alignment;
}
std::size_t monotonic_buffer_resource::remaining_storage(std::size_t alignment) const BOOST_NOEXCEPT
{
std::size_t ignore_this;
return this->remaining_storage(alignment, ignore_this);
}
const void *monotonic_buffer_resource::current_buffer() const BOOST_NOEXCEPT
{ return m_current_buffer; }
std::size_t monotonic_buffer_resource::next_buffer_size() const BOOST_NOEXCEPT
{ return m_next_buffer_size; }
void *monotonic_buffer_resource::allocate_from_current(std::size_t aligner, std::size_t bytes)
{
char * p = (char*)m_current_buffer + aligner;
m_current_buffer = p + bytes;
m_current_buffer_size -= aligner + bytes;
return p;
}
void* monotonic_buffer_resource::do_allocate(std::size_t bytes, std::size_t alignment)
{
if(alignment > memory_resource::max_align)
throw_bad_alloc();
//See if there is room in current buffer
std::size_t aligner = 0u;
if(this->remaining_storage(alignment, aligner) < bytes){
//Update next_buffer_size to at least bytes
this->increase_next_buffer_at_least_to(bytes);
//Now allocate and update internal data
m_current_buffer = (char*)m_memory_blocks.allocate(m_next_buffer_size);
m_current_buffer_size = m_next_buffer_size;
this->increase_next_buffer();
}
//Enough internal storage, extract from it
return this->allocate_from_current(aligner, bytes);
}
void monotonic_buffer_resource::do_deallocate(void* p, std::size_t bytes, std::size_t alignment) BOOST_NOEXCEPT
{ (void)p; (void)bytes; (void)alignment; }
bool monotonic_buffer_resource::do_is_equal(const memory_resource& other) const BOOST_NOEXCEPT
{ return this == dynamic_cast<const monotonic_buffer_resource*>(&other); }
} //namespace pmr {
} //namespace container {
} //namespace boost {
#include <boost/container/detail/config_end.hpp>
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