////////////////////////////////////////////////////////////////////////////// | |
// | |
// (C) Copyright Ion Gaztanaga 2005-2009. 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/interprocess for documentation. | |
// | |
////////////////////////////////////////////////////////////////////////////// | |
#ifndef BOOST_INTERPROCESS_MEM_ALGO_DETAIL_SIMPLE_SEQ_FIT_IMPL_HPP | |
#define BOOST_INTERPROCESS_MEM_ALGO_DETAIL_SIMPLE_SEQ_FIT_IMPL_HPP | |
#if (defined _MSC_VER) && (_MSC_VER >= 1200) | |
# pragma once | |
#endif | |
#include <boost/interprocess/detail/config_begin.hpp> | |
#include <boost/interprocess/detail/workaround.hpp> | |
#include <boost/pointer_to_other.hpp> | |
#include <boost/interprocess/interprocess_fwd.hpp> | |
#include <boost/interprocess/containers/allocation_type.hpp> | |
#include <boost/interprocess/offset_ptr.hpp> | |
#include <boost/interprocess/sync/interprocess_mutex.hpp> | |
#include <boost/interprocess/exceptions.hpp> | |
#include <boost/interprocess/detail/utilities.hpp> | |
#include <boost/interprocess/detail/multi_segment_services.hpp> | |
#include <boost/type_traits/alignment_of.hpp> | |
#include <boost/type_traits/type_with_alignment.hpp> | |
#include <boost/interprocess/detail/min_max.hpp> | |
#include <boost/interprocess/sync/scoped_lock.hpp> | |
#include <algorithm> | |
#include <utility> | |
#include <cstring> | |
#include <boost/assert.hpp> | |
#include <new> | |
/*!\file | |
Describes sequential fit algorithm used to allocate objects in shared memory. | |
This class is intended as a base class for single segment and multi-segment | |
implementations. | |
*/ | |
namespace boost { | |
namespace interprocess { | |
namespace detail { | |
/*!This class implements the simple sequential fit algorithm with a simply | |
linked list of free buffers. | |
This class is intended as a base class for single segment and multi-segment | |
implementations.*/ | |
template<class MutexFamily, class VoidPointer> | |
class simple_seq_fit_impl | |
{ | |
//Non-copyable | |
simple_seq_fit_impl(); | |
simple_seq_fit_impl(const simple_seq_fit_impl &); | |
simple_seq_fit_impl &operator=(const simple_seq_fit_impl &); | |
public: | |
/*!Shared interprocess_mutex family used for the rest of the Interprocess framework*/ | |
typedef MutexFamily mutex_family; | |
/*!Pointer type to be used with the rest of the Interprocess framework*/ | |
typedef VoidPointer void_pointer; | |
private: | |
struct block_ctrl; | |
typedef typename boost:: | |
pointer_to_other<void_pointer, block_ctrl>::type block_ctrl_ptr; | |
/*!Block control structure*/ | |
struct block_ctrl | |
{ | |
/*!Offset pointer to the next block.*/ | |
block_ctrl_ptr m_next; | |
/*!This block's memory size (including block_ctrl | |
header) in BasicSize units*/ | |
std::size_t m_size; | |
std::size_t get_user_bytes() const | |
{ return this->m_size*Alignment - BlockCtrlBytes; } | |
std::size_t get_total_bytes() const | |
{ return this->m_size*Alignment; } | |
static block_ctrl *get_block_from_addr(void *addr) | |
{ | |
return reinterpret_cast<block_ctrl*> | |
(reinterpret_cast<char*>(addr) - BlockCtrlBytes); | |
} | |
void *get_addr() const | |
{ | |
return reinterpret_cast<block_ctrl*> | |
(reinterpret_cast<const char*>(this) + BlockCtrlBytes); | |
} | |
}; | |
/*!Shared interprocess_mutex to protect memory allocate/deallocate*/ | |
typedef typename MutexFamily::mutex_type interprocess_mutex; | |
/*!This struct includes needed data and derives from | |
interprocess_mutex to allow EBO when using null interprocess_mutex*/ | |
struct header_t : public interprocess_mutex | |
{ | |
/*!Pointer to the first free block*/ | |
block_ctrl m_root; | |
/*!Allocated bytes for internal checking*/ | |
std::size_t m_allocated; | |
/*!The size of the memory segment*/ | |
std::size_t m_size; | |
} m_header; | |
public: | |
/*!Constructor. "size" is the total size of the managed memory segment, | |
"extra_hdr_bytes" indicates the extra bytes beginning in the sizeof(simple_seq_fit_impl) | |
offset that the allocator should not use at all.*/ | |
simple_seq_fit_impl (std::size_t size, std::size_t extra_hdr_bytes); | |
/*!Destructor.*/ | |
~simple_seq_fit_impl(); | |
/*!Obtains the minimum size needed by the algorithm*/ | |
static std::size_t get_min_size (std::size_t extra_hdr_bytes); | |
//Functions for single segment management | |
/*!Allocates bytes, returns 0 if there is not more memory*/ | |
void* allocate (std::size_t nbytes); | |
/*!Deallocates previously allocated bytes*/ | |
void deallocate (void *addr); | |
/*!Returns the size of the memory segment*/ | |
std::size_t get_size() const; | |
/*!Increases managed memory in extra_size bytes more*/ | |
void grow(std::size_t extra_size); | |
/*!Returns true if all allocated memory has been deallocated*/ | |
bool all_memory_deallocated(); | |
/*!Makes an internal sanity check and returns true if success*/ | |
bool check_sanity(); | |
//!Initializes to zero all the memory that's not in use. | |
//!This function is normally used for security reasons. | |
void clear_free_memory(); | |
std::pair<void *, bool> | |
allocation_command (boost::interprocess::allocation_type command, std::size_t limit_size, | |
std::size_t preferred_size,std::size_t &received_size, | |
void *reuse_ptr = 0, std::size_t backwards_multiple = 1); | |
/*!Returns the size of the buffer previously allocated pointed by ptr*/ | |
std::size_t size(void *ptr) const; | |
/*!Allocates aligned bytes, returns 0 if there is not more memory. | |
Alignment must be power of 2*/ | |
void* allocate_aligned (std::size_t nbytes, std::size_t alignment); | |
/*!Allocates bytes, if there is no more memory, it executes functor | |
f(std::size_t) to allocate a new segment to manage. The functor returns | |
std::pair<void*, std::size_t> indicating the base address and size of | |
the new segment. If the new segment can't be allocated, allocate | |
it will return 0.*/ | |
void* multi_allocate(std::size_t nbytes); | |
private: | |
/*!Real allocation algorithm with min allocation option*/ | |
std::pair<void *, bool> priv_allocate(boost::interprocess::allocation_type command | |
,std::size_t min_size | |
,std::size_t preferred_size | |
,std::size_t &received_size | |
,void *reuse_ptr = 0); | |
/*!Returns next block if it's free. | |
Returns 0 if next block is not free.*/ | |
block_ctrl *priv_next_block_if_free(block_ctrl *ptr); | |
/*!Returns previous block's if it's free. | |
Returns 0 if previous block is not free.*/ | |
std::pair<block_ctrl*, block_ctrl*>priv_prev_block_if_free(block_ctrl *ptr); | |
/*!Real expand function implementation*/ | |
bool priv_expand(void *ptr | |
,std::size_t min_size, std::size_t preferred_size | |
,std::size_t &received_size); | |
/*!Real expand to both sides implementation*/ | |
void* priv_expand_both_sides(boost::interprocess::allocation_type command | |
,std::size_t min_size | |
,std::size_t preferred_size | |
,std::size_t &received_size | |
,void *reuse_ptr | |
,bool only_preferred_backwards); | |
/*!Real shrink function implementation*/ | |
bool priv_shrink(void *ptr | |
,std::size_t max_size, std::size_t preferred_size | |
,std::size_t &received_size); | |
//!Real private aligned allocation function | |
void* priv_allocate_aligned (std::size_t nbytes, std::size_t alignment); | |
/*!Checks if block has enough memory and splits/unlinks the block | |
returning the address to the users*/ | |
void* priv_check_and_allocate(std::size_t units | |
,block_ctrl* prev | |
,block_ctrl* block | |
,std::size_t &received_size); | |
/*!Real deallocation algorithm*/ | |
void priv_deallocate(void *addr); | |
/*!Makes a new memory portion available for allocation*/ | |
void priv_add_segment(void *addr, std::size_t size); | |
enum { Alignment = boost::alignment_of<boost::detail::max_align>::value }; | |
enum { BlockCtrlBytes = detail::ct_rounded_size<sizeof(block_ctrl), Alignment>::value }; | |
enum { BlockCtrlSize = BlockCtrlBytes/Alignment }; | |
enum { MinBlockSize = BlockCtrlSize + Alignment }; | |
public: | |
enum { PayloadPerAllocation = BlockCtrlBytes }; | |
}; | |
template<class MutexFamily, class VoidPointer> | |
inline simple_seq_fit_impl<MutexFamily, VoidPointer>:: | |
simple_seq_fit_impl(std::size_t size, std::size_t extra_hdr_bytes) | |
{ | |
//Initialize sizes and counters | |
m_header.m_allocated = 0; | |
m_header.m_size = size; | |
//Initialize pointers | |
std::size_t block1_off = detail::get_rounded_size(sizeof(*this)+extra_hdr_bytes, Alignment); | |
m_header.m_root.m_next = reinterpret_cast<block_ctrl*> | |
(reinterpret_cast<char*>(this) + block1_off); | |
m_header.m_root.m_next->m_size = (size - block1_off)/Alignment; | |
m_header.m_root.m_next->m_next = &m_header.m_root; | |
} | |
template<class MutexFamily, class VoidPointer> | |
inline simple_seq_fit_impl<MutexFamily, VoidPointer>::~simple_seq_fit_impl() | |
{ | |
//There is a memory leak! | |
// BOOST_ASSERT(m_header.m_allocated == 0); | |
// BOOST_ASSERT(m_header.m_root.m_next->m_next == block_ctrl_ptr(&m_header.m_root)); | |
} | |
template<class MutexFamily, class VoidPointer> | |
inline void simple_seq_fit_impl<MutexFamily, VoidPointer>::grow(std::size_t extra_size) | |
{ | |
//Old highest address block's end offset | |
std::size_t old_end = m_header.m_size/Alignment*Alignment; | |
//Update managed buffer's size | |
m_header.m_size += extra_size; | |
//We need at least MinBlockSize blocks to create a new block | |
if((m_header.m_size - old_end) < MinBlockSize){ | |
return; | |
} | |
//We'll create a new free block with extra_size bytes | |
block_ctrl *new_block = reinterpret_cast<block_ctrl*> | |
(reinterpret_cast<char*>(this) + old_end); | |
new_block->m_next = 0; | |
new_block->m_size = (m_header.m_size - old_end)/Alignment; | |
m_header.m_allocated += new_block->m_size*Alignment; | |
this->priv_deallocate(reinterpret_cast<char*>(new_block) + BlockCtrlBytes); | |
} | |
template<class MutexFamily, class VoidPointer> | |
inline void simple_seq_fit_impl<MutexFamily, VoidPointer>::priv_add_segment(void *addr, std::size_t size) | |
{ | |
//Check size | |
BOOST_ASSERT(!(size < MinBlockSize)); | |
if(size < MinBlockSize) | |
return; | |
//Construct big block using the new segment | |
block_ctrl *new_block = static_cast<block_ctrl *>(addr); | |
new_block->m_size = size/Alignment; | |
new_block->m_next = 0; | |
//Simulate this block was previously allocated | |
m_header.m_allocated += new_block->m_size*Alignment; | |
//Return block and insert it in the free block list | |
this->priv_deallocate(reinterpret_cast<char*>(new_block) + BlockCtrlBytes); | |
} | |
template<class MutexFamily, class VoidPointer> | |
inline std::size_t simple_seq_fit_impl<MutexFamily, VoidPointer>::get_size() const | |
{ return m_header.m_size; } | |
template<class MutexFamily, class VoidPointer> | |
inline std::size_t simple_seq_fit_impl<MutexFamily, VoidPointer>:: | |
get_min_size (std::size_t extra_hdr_bytes) | |
{ | |
return detail::get_rounded_size(sizeof(simple_seq_fit_impl)+extra_hdr_bytes | |
,Alignment) | |
+ MinBlockSize; | |
} | |
template<class MutexFamily, class VoidPointer> | |
inline bool simple_seq_fit_impl<MutexFamily, VoidPointer>:: | |
all_memory_deallocated() | |
{ | |
//----------------------- | |
boost::interprocess::scoped_lock<interprocess_mutex> guard(m_header); | |
//----------------------- | |
return m_header.m_allocated == 0 && | |
detail::get_pointer(m_header.m_root.m_next->m_next) == &m_header.m_root; | |
} | |
template<class MutexFamily, class VoidPointer> | |
inline void simple_seq_fit_impl<MutexFamily, VoidPointer>::clear_free_memory() | |
{ | |
//----------------------- | |
boost::interprocess::scoped_lock<interprocess_mutex> guard(m_header); | |
//----------------------- | |
block_ctrl *block = detail::get_pointer(m_header.m_root.m_next); | |
//Iterate through all free portions | |
do{ | |
//Just clear user the memory part reserved for the user | |
std::memset( reinterpret_cast<char*>(block) + BlockCtrlBytes | |
, 0 | |
, block->m_size*Alignment - BlockCtrlBytes); | |
block = detail::get_pointer(block->m_next); | |
} | |
while(block != &m_header.m_root); | |
} | |
template<class MutexFamily, class VoidPointer> | |
inline bool simple_seq_fit_impl<MutexFamily, VoidPointer>:: | |
check_sanity() | |
{ | |
//----------------------- | |
boost::interprocess::scoped_lock<interprocess_mutex> guard(m_header); | |
//----------------------- | |
block_ctrl *block = detail::get_pointer(m_header.m_root.m_next); | |
std::size_t free_memory = 0; | |
//Iterate through all blocks obtaining their size | |
do{ | |
//Free blocks's next must be always valid | |
block_ctrl *next = detail::get_pointer(block->m_next); | |
if(!next){ | |
return false; | |
} | |
free_memory += block->m_size*Alignment; | |
block = next; | |
} | |
while(block != &m_header.m_root); | |
//Check allocated bytes are less than size | |
if(m_header.m_allocated > m_header.m_size){ | |
return false; | |
} | |
//Check free bytes are less than size | |
if(free_memory > m_header.m_size){ | |
return false; | |
} | |
return true; | |
} | |
template<class MutexFamily, class VoidPointer> | |
inline void* simple_seq_fit_impl<MutexFamily, VoidPointer>:: | |
allocate(std::size_t nbytes) | |
{ | |
//----------------------- | |
boost::interprocess::scoped_lock<interprocess_mutex> guard(m_header); | |
//----------------------- | |
std::size_t ignore; | |
return priv_allocate(boost::interprocess::allocate_new, nbytes, nbytes, ignore).first; | |
} | |
template<class MutexFamily, class VoidPointer> | |
inline void* simple_seq_fit_impl<MutexFamily, VoidPointer>:: | |
allocate_aligned(std::size_t nbytes, std::size_t alignment) | |
{ | |
//----------------------- | |
boost::interprocess::scoped_lock<interprocess_mutex> guard(m_header); | |
//----------------------- | |
return priv_allocate_aligned(nbytes, alignment); | |
} | |
template<class MutexFamily, class VoidPointer> | |
inline std::pair<void *, bool> simple_seq_fit_impl<MutexFamily, VoidPointer>:: | |
allocation_command (boost::interprocess::allocation_type command, std::size_t min_size, | |
std::size_t preferred_size,std::size_t &received_size, | |
void *reuse_ptr, std::size_t backwards_multiple) | |
{ | |
//----------------------- | |
boost::interprocess::scoped_lock<interprocess_mutex> guard(m_header); | |
//----------------------- | |
(void)backwards_multiple; | |
command &= ~boost::interprocess::expand_bwd; | |
if(!command) | |
return std::pair<void *, bool>(0, false); | |
return priv_allocate(command, min_size, preferred_size, received_size, reuse_ptr); | |
} | |
template<class MutexFamily, class VoidPointer> | |
inline std::size_t simple_seq_fit_impl<MutexFamily, VoidPointer>:: | |
size(void *ptr) const | |
{ | |
//We need no synchronization since this block is not going | |
//to be modified | |
//Obtain the real size of the block | |
block_ctrl *block = reinterpret_cast<block_ctrl*> | |
(reinterpret_cast<char*>(ptr) - BlockCtrlBytes); | |
return block->m_size*Alignment - BlockCtrlBytes; | |
} | |
template<class MutexFamily, class VoidPointer> | |
inline void* simple_seq_fit_impl<MutexFamily, VoidPointer>:: | |
multi_allocate(std::size_t nbytes) | |
{ | |
//----------------------- | |
boost::interprocess::scoped_lock<interprocess_mutex> guard(m_header); | |
//----------------------- | |
//Multisegment pointer. Let's try first the normal allocation | |
//since it's faster. | |
std::size_t ignore; | |
void *addr = this->priv_allocate(boost::interprocess::allocate_new, nbytes, nbytes, ignore).first; | |
if(!addr){ | |
//If this fails we will try the allocation through the segment | |
//creator. | |
std::size_t group, id; | |
//Obtain the segment group of this segment | |
void_pointer::get_group_and_id(this, group, id); | |
if(group == 0){ | |
//Ooops, group 0 is not valid. | |
return 0; | |
} | |
//Now obtain the polymorphic functor that creates | |
//new segments and try to allocate again. | |
boost::interprocess::multi_segment_services *p_services = | |
static_cast<boost::interprocess::multi_segment_services*> | |
(void_pointer::find_group_data(group)); | |
BOOST_ASSERT(p_services); | |
std::pair<void *, std::size_t> ret = | |
p_services->create_new_segment(MinBlockSize > nbytes ? MinBlockSize : nbytes); | |
if(ret.first){ | |
priv_add_segment(ret.first, ret.second); | |
addr = this->priv_allocate(boost::interprocess::allocate_new, nbytes, nbytes, ignore).first; | |
} | |
} | |
return addr; | |
} | |
template<class MutexFamily, class VoidPointer> | |
void* simple_seq_fit_impl<MutexFamily, VoidPointer>:: | |
priv_expand_both_sides(boost::interprocess::allocation_type command | |
,std::size_t min_size | |
,std::size_t preferred_size | |
,std::size_t &received_size | |
,void *reuse_ptr | |
,bool only_preferred_backwards) | |
{ | |
typedef std::pair<block_ctrl *, block_ctrl *> prev_block_t; | |
block_ctrl *reuse = block_ctrl::get_block_from_addr(reuse_ptr); | |
received_size = 0; | |
if(this->size(reuse_ptr) > min_size){ | |
received_size = this->size(reuse_ptr); | |
return reuse_ptr; | |
} | |
if(command & boost::interprocess::expand_fwd){ | |
if(priv_expand(reuse_ptr, min_size, preferred_size, received_size)) | |
return reuse_ptr; | |
} | |
else{ | |
received_size = this->size(reuse_ptr); | |
} | |
if(command & boost::interprocess::expand_bwd){ | |
std::size_t extra_forward = !received_size ? 0 : received_size + BlockCtrlBytes; | |
prev_block_t prev_pair = priv_prev_block_if_free(reuse); | |
block_ctrl *prev = prev_pair.second; | |
if(!prev){ | |
return 0; | |
} | |
std::size_t needs_backwards = | |
detail::get_rounded_size(preferred_size - extra_forward, Alignment); | |
if(!only_preferred_backwards){ | |
needs_backwards = | |
max_value(detail::get_rounded_size(min_size - extra_forward, Alignment) | |
,min_value(prev->get_user_bytes(), needs_backwards)); | |
} | |
//Check if previous block has enough size | |
if((prev->get_user_bytes()) >= needs_backwards){ | |
//Now take all next space. This will succeed | |
if(!priv_expand(reuse_ptr, received_size, received_size, received_size)){ | |
BOOST_ASSERT(0); | |
} | |
//We need a minimum size to split the previous one | |
if((prev->get_user_bytes() - needs_backwards) > 2*BlockCtrlBytes){ | |
block_ctrl *new_block = reinterpret_cast<block_ctrl *> | |
(reinterpret_cast<char*>(reuse) - needs_backwards - BlockCtrlBytes); | |
new_block->m_next = 0; | |
new_block->m_size = | |
BlockCtrlSize + (needs_backwards + extra_forward)/Alignment; | |
prev->m_size = | |
(prev->get_total_bytes() - needs_backwards)/Alignment - BlockCtrlSize; | |
received_size = needs_backwards + extra_forward; | |
m_header.m_allocated += needs_backwards + BlockCtrlBytes; | |
return new_block->get_addr(); | |
} | |
else{ | |
//Just merge the whole previous block | |
block_ctrl *prev_2_block = prev_pair.first; | |
//Update received size and allocation | |
received_size = extra_forward + prev->get_user_bytes(); | |
m_header.m_allocated += prev->get_total_bytes(); | |
//Now unlink it from previous block | |
prev_2_block->m_next = prev->m_next; | |
prev->m_size = reuse->m_size + prev->m_size; | |
prev->m_next = 0; | |
return prev->get_addr(); | |
} | |
} | |
} | |
return 0; | |
} | |
template<class MutexFamily, class VoidPointer> | |
std::pair<void *, bool> simple_seq_fit_impl<MutexFamily, VoidPointer>:: | |
priv_allocate(boost::interprocess::allocation_type command | |
,std::size_t limit_size | |
,std::size_t preferred_size | |
,std::size_t &received_size | |
,void *reuse_ptr) | |
{ | |
if(command & boost::interprocess::shrink_in_place){ | |
bool success = | |
this->priv_shrink(reuse_ptr, limit_size, preferred_size, received_size); | |
return std::pair<void *, bool> ((success ? reuse_ptr : 0), true); | |
} | |
typedef std::pair<void *, bool> return_type; | |
received_size = 0; | |
if(limit_size > preferred_size) | |
return return_type(0, false); | |
//Number of units to request (including block_ctrl header) | |
std::size_t nunits = detail::get_rounded_size(preferred_size, Alignment)/Alignment + BlockCtrlSize; | |
//Get the root and the first memory block | |
block_ctrl *prev = &m_header.m_root; | |
block_ctrl *block = detail::get_pointer(prev->m_next); | |
block_ctrl *root = &m_header.m_root; | |
block_ctrl *biggest_block = 0; | |
block_ctrl *prev_biggest_block = 0; | |
std::size_t biggest_size = limit_size; | |
//Expand in place | |
//reuse_ptr, limit_size, preferred_size, received_size | |
// | |
if(reuse_ptr && (command & (boost::interprocess::expand_fwd | boost::interprocess::expand_bwd))){ | |
void *ret = priv_expand_both_sides | |
(command, limit_size, preferred_size, received_size, reuse_ptr, true); | |
if(ret) | |
return return_type(ret, true); | |
} | |
if(command & boost::interprocess::allocate_new){ | |
received_size = 0; | |
while(block != root){ | |
//Update biggest block pointers | |
if(block->m_size > biggest_size){ | |
prev_biggest_block = prev; | |
biggest_size = block->m_size; | |
biggest_block = block; | |
} | |
void *addr = this->priv_check_and_allocate(nunits, prev, block, received_size); | |
if(addr) return return_type(addr, false); | |
//Bad luck, let's check next block | |
prev = block; | |
block = detail::get_pointer(block->m_next); | |
} | |
//Bad luck finding preferred_size, now if we have any biggest_block | |
//try with this block | |
if(biggest_block){ | |
received_size = biggest_block->m_size*Alignment - BlockCtrlSize; | |
nunits = detail::get_rounded_size(limit_size, Alignment)/Alignment + BlockCtrlSize; | |
void *ret = this->priv_check_and_allocate | |
(nunits, prev_biggest_block, biggest_block, received_size); | |
if(ret) | |
return return_type(ret, false); | |
} | |
} | |
//Now try to expand both sides with min size | |
if(reuse_ptr && (command & (boost::interprocess::expand_fwd | boost::interprocess::expand_bwd))){ | |
return return_type(priv_expand_both_sides | |
(command, limit_size, preferred_size, received_size, reuse_ptr, false), true); | |
} | |
return return_type(0, false); | |
} | |
template<class MutexFamily, class VoidPointer> | |
inline typename simple_seq_fit_impl<MutexFamily, VoidPointer>::block_ctrl * | |
simple_seq_fit_impl<MutexFamily, VoidPointer>:: | |
priv_next_block_if_free | |
(typename simple_seq_fit_impl<MutexFamily, VoidPointer>::block_ctrl *ptr) | |
{ | |
//Take the address where the next block should go | |
block_ctrl *next_block = reinterpret_cast<block_ctrl*> | |
(reinterpret_cast<char*>(ptr) + ptr->m_size*Alignment); | |
//Check if the adjacent block is in the managed segment | |
std::size_t distance = (reinterpret_cast<char*>(next_block) - reinterpret_cast<char*>(this))/Alignment; | |
if(distance >= (m_header.m_size/Alignment)){ | |
//"next_block" does not exist so we can't expand "block" | |
return 0; | |
} | |
if(!next_block->m_next) | |
return 0; | |
return next_block; | |
} | |
template<class MutexFamily, class VoidPointer> | |
inline | |
std::pair<typename simple_seq_fit_impl<MutexFamily, VoidPointer>::block_ctrl * | |
,typename simple_seq_fit_impl<MutexFamily, VoidPointer>::block_ctrl *> | |
simple_seq_fit_impl<MutexFamily, VoidPointer>:: | |
priv_prev_block_if_free | |
(typename simple_seq_fit_impl<MutexFamily, VoidPointer>::block_ctrl *ptr) | |
{ | |
typedef std::pair<block_ctrl *, block_ctrl *> prev_pair_t; | |
//Take the address where the previous block should go | |
block_ctrl *root = &m_header.m_root; | |
block_ctrl *prev_2_block = root; | |
block_ctrl *prev_block = detail::get_pointer(root->m_next); | |
while((reinterpret_cast<char*>(prev_block) + prev_block->m_size*Alignment) | |
!= (reinterpret_cast<char*>(ptr)) | |
&& prev_block != root){ | |
prev_2_block = prev_block; | |
prev_block = detail::get_pointer(prev_block->m_next); | |
} | |
if(prev_block == root || !prev_block->m_next) | |
return prev_pair_t(0, 0); | |
//Check if the previous block is in the managed segment | |
std::size_t distance = (reinterpret_cast<char*>(prev_block) - reinterpret_cast<char*>(this))/Alignment; | |
if(distance >= (m_header.m_size/Alignment)){ | |
//"previous_block" does not exist so we can't expand "block" | |
return prev_pair_t(0, 0); | |
} | |
return prev_pair_t(prev_2_block, prev_block); | |
} | |
template<class MutexFamily, class VoidPointer> | |
inline bool simple_seq_fit_impl<MutexFamily, VoidPointer>:: | |
priv_expand (void *ptr | |
,std::size_t min_size | |
,std::size_t preferred_size | |
,std::size_t &received_size) | |
{ | |
//Obtain the real size of the block | |
block_ctrl *block = reinterpret_cast<block_ctrl*> | |
(reinterpret_cast<char*>(ptr) - BlockCtrlBytes); | |
std::size_t old_block_size = block->m_size; | |
//All used blocks' next is marked with 0 so check it | |
BOOST_ASSERT(block->m_next == 0); | |
//Put this to a safe value | |
received_size = old_block_size*Alignment - BlockCtrlBytes; | |
//Now translate it to Alignment units | |
min_size = detail::get_rounded_size(min_size, Alignment)/Alignment; | |
preferred_size = detail::get_rounded_size(preferred_size, Alignment)/Alignment; | |
//Some parameter checks | |
if(min_size > preferred_size) | |
return false; | |
std::size_t data_size = old_block_size - BlockCtrlSize; | |
if(data_size >= min_size) | |
return true; | |
block_ctrl *next_block = priv_next_block_if_free(block); | |
if(!next_block){ | |
return false; | |
} | |
//Is "block" + "next_block" big enough? | |
std::size_t merged_size = old_block_size + next_block->m_size; | |
//Now we can expand this block further than before | |
received_size = merged_size*Alignment - BlockCtrlBytes; | |
if(merged_size < (min_size + BlockCtrlSize)){ | |
return false; | |
} | |
//We can fill expand. Merge both blocks, | |
block->m_next = next_block->m_next; | |
block->m_size = merged_size; | |
//Find the previous free block of next_block | |
block_ctrl *prev = &m_header.m_root; | |
while(detail::get_pointer(prev->m_next) != next_block){ | |
prev = detail::get_pointer(prev->m_next); | |
} | |
//Now insert merged block in the free list | |
//This allows reusing allocation logic in this function | |
m_header.m_allocated -= old_block_size*Alignment; | |
prev->m_next = block; | |
//Now use check and allocate to do the allocation logic | |
preferred_size += BlockCtrlSize; | |
std::size_t nunits = preferred_size < merged_size ? preferred_size : merged_size; | |
//This must success since nunits is less than merged_size! | |
if(!this->priv_check_and_allocate (nunits, prev, block, received_size)){ | |
//Something very ugly is happening here. This is a bug | |
//or there is memory corruption | |
BOOST_ASSERT(0); | |
return false; | |
} | |
return true; | |
} | |
template<class MutexFamily, class VoidPointer> | |
inline bool simple_seq_fit_impl<MutexFamily, VoidPointer>:: | |
priv_shrink (void *ptr | |
,std::size_t max_size | |
,std::size_t preferred_size | |
,std::size_t &received_size) | |
{ | |
//Obtain the real size of the block | |
block_ctrl *block = reinterpret_cast<block_ctrl*> | |
(reinterpret_cast<char*>(ptr) - BlockCtrlBytes); | |
std::size_t block_size = block->m_size; | |
//All used blocks' next is marked with 0 so check it | |
BOOST_ASSERT(block->m_next == 0); | |
//Put this to a safe value | |
received_size = block_size*Alignment - BlockCtrlBytes; | |
//Now translate it to Alignment units | |
max_size = max_size/Alignment; | |
preferred_size = detail::get_rounded_size(preferred_size, Alignment)/Alignment; | |
//Some parameter checks | |
if(max_size < preferred_size) | |
return false; | |
std::size_t data_size = block_size - BlockCtrlSize; | |
if(data_size < preferred_size) | |
return false; | |
if(data_size == preferred_size) | |
return true; | |
//We must be able to create at least a new empty block | |
if((data_size - preferred_size) < BlockCtrlSize){ | |
return false; | |
} | |
//Now we can just rewrite the size of the old buffer | |
block->m_size = preferred_size + BlockCtrlSize; | |
//Update new size | |
received_size = preferred_size*Alignment; | |
//We create the new block | |
block = reinterpret_cast<block_ctrl*> | |
(reinterpret_cast<char*>(block) + block->m_size*Alignment); | |
//Write control data to simulate this new block was previously allocated | |
block->m_next = 0; | |
block->m_size = data_size - preferred_size; | |
//Now deallocate the new block to insert it in the free list | |
this->priv_deallocate(reinterpret_cast<char*>(block)+BlockCtrlBytes); | |
return true; | |
} | |
template<class MutexFamily, class VoidPointer> | |
inline void* simple_seq_fit_impl<MutexFamily, VoidPointer>:: | |
priv_allocate_aligned(std::size_t nbytes, std::size_t alignment) | |
{ | |
//Ensure power of 2 | |
if ((alignment & (alignment - std::size_t(1u))) != 0){ | |
//Alignment is not power of two | |
BOOST_ASSERT((alignment & (alignment - std::size_t(1u))) != 0); | |
return 0; | |
} | |
std::size_t ignore; | |
if(alignment <= Alignment){ | |
return priv_allocate(boost::interprocess::allocate_new, nbytes, nbytes, ignore).first; | |
} | |
std::size_t request = | |
nbytes + alignment + MinBlockSize*Alignment - BlockCtrlBytes; | |
void *buffer = priv_allocate(boost::interprocess::allocate_new, request, request, ignore).first; | |
if(!buffer) | |
return 0; | |
else if ((((std::size_t)(buffer)) % alignment) == 0) | |
return buffer; | |
char *aligned_portion = reinterpret_cast<char*> | |
(reinterpret_cast<std::size_t>(static_cast<char*>(buffer) + alignment - 1) & -alignment); | |
char *pos = ((aligned_portion - reinterpret_cast<char*>(buffer)) >= (MinBlockSize*Alignment)) ? | |
aligned_portion : (aligned_portion + alignment); | |
block_ctrl *first = reinterpret_cast<block_ctrl*> | |
(reinterpret_cast<char*>(buffer) - BlockCtrlBytes); | |
block_ctrl *second = reinterpret_cast<block_ctrl*>(pos - BlockCtrlBytes); | |
std::size_t old_size = first->m_size; | |
first->m_size = (reinterpret_cast<char*>(second) - reinterpret_cast<char*>(first))/Alignment; | |
second->m_size = old_size - first->m_size; | |
//Write control data to simulate this new block was previously allocated | |
second->m_next = 0; | |
//Now deallocate the new block to insert it in the free list | |
this->priv_deallocate(reinterpret_cast<char*>(first) + BlockCtrlBytes); | |
return reinterpret_cast<char*>(second) + BlockCtrlBytes; | |
} | |
template<class MutexFamily, class VoidPointer> inline | |
void* simple_seq_fit_impl<MutexFamily, VoidPointer>::priv_check_and_allocate | |
(std::size_t nunits | |
,typename simple_seq_fit_impl<MutexFamily, VoidPointer>::block_ctrl* prev | |
,typename simple_seq_fit_impl<MutexFamily, VoidPointer>::block_ctrl* block | |
,std::size_t &received_size) | |
{ | |
std::size_t upper_nunits = nunits + BlockCtrlSize; | |
bool found = false; | |
if (block->m_size > upper_nunits){ | |
//This block is bigger than needed, split it in | |
//two blocks, the first's size will be (block->m_size-units) | |
//the second's size (units) | |
std::size_t total_size = block->m_size; | |
block->m_size = nunits; | |
block_ctrl *new_block = reinterpret_cast<block_ctrl*> | |
(reinterpret_cast<char*>(block) + Alignment*nunits); | |
new_block->m_size = total_size - nunits; | |
new_block->m_next = block->m_next; | |
prev->m_next = new_block; | |
found = true; | |
} | |
else if (block->m_size >= nunits){ | |
//This block has exactly the right size with an extra | |
//unusable extra bytes. | |
prev->m_next = block->m_next; | |
found = true; | |
} | |
if(found){ | |
//We need block_ctrl for deallocation stuff, so | |
//return memory user can overwrite | |
m_header.m_allocated += block->m_size*Alignment; | |
received_size = block->m_size*Alignment - BlockCtrlBytes; | |
//Mark the block as allocated | |
block->m_next = 0; | |
//Check alignment | |
BOOST_ASSERT(((reinterpret_cast<char*>(block) - reinterpret_cast<char*>(this)) | |
% Alignment) == 0 ); | |
return reinterpret_cast<char*>(block) + BlockCtrlBytes; | |
} | |
return 0; | |
} | |
template<class MutexFamily, class VoidPointer> | |
void simple_seq_fit_impl<MutexFamily, VoidPointer>::deallocate(void* addr) | |
{ | |
if(!addr) return; | |
//----------------------- | |
boost::interprocess::scoped_lock<interprocess_mutex> guard(m_header); | |
//----------------------- | |
return this->priv_deallocate(addr); | |
} | |
template<class MutexFamily, class VoidPointer> | |
void simple_seq_fit_impl<MutexFamily, VoidPointer>::priv_deallocate(void* addr) | |
{ | |
if(!addr) return; | |
//Let's get free block list. List is always sorted | |
//by memory address to allow block merging. | |
//Pointer next always points to the first | |
//(lower address) block | |
block_ctrl_ptr prev = &m_header.m_root; | |
block_ctrl_ptr pos = m_header.m_root.m_next; | |
block_ctrl_ptr block = reinterpret_cast<block_ctrl*> | |
(reinterpret_cast<char*>(addr) - BlockCtrlBytes); | |
//All used blocks' next is marked with 0 so check it | |
BOOST_ASSERT(block->m_next == 0); | |
//Check if alignment and block size are right | |
BOOST_ASSERT((reinterpret_cast<char*>(addr) - reinterpret_cast<char*>(this)) | |
% Alignment == 0 ); | |
std::size_t total_size = Alignment*block->m_size; | |
BOOST_ASSERT(m_header.m_allocated >= total_size); | |
//Update used memory count | |
m_header.m_allocated -= total_size; | |
//Let's find the previous and the next block of the block to deallocate | |
//This ordering comparison must be done with original pointers | |
//types since their mapping to raw pointers can be different | |
//in each process | |
while((detail::get_pointer(pos) != &m_header.m_root) && (block > pos)){ | |
prev = pos; | |
pos = pos->m_next; | |
} | |
//Try to combine with upper block | |
if ((reinterpret_cast<char*>(detail::get_pointer(block)) | |
+ Alignment*block->m_size) == | |
reinterpret_cast<char*>(detail::get_pointer(pos))){ | |
block->m_size += pos->m_size; | |
block->m_next = pos->m_next; | |
} | |
else{ | |
block->m_next = pos; | |
} | |
//Try to combine with lower block | |
if ((reinterpret_cast<char*>(detail::get_pointer(prev)) | |
+ Alignment*prev->m_size) == | |
reinterpret_cast<char*>(detail::get_pointer(block))){ | |
prev->m_size += block->m_size; | |
prev->m_next = block->m_next; | |
} | |
else{ | |
prev->m_next = block; | |
} | |
} | |
} //namespace detail { | |
} //namespace interprocess { | |
} //namespace boost { | |
#include <boost/interprocess/detail/config_end.hpp> | |
#endif //#ifndef BOOST_INTERPROCESS_MEM_ALGO_DETAIL_SIMPLE_SEQ_FIT_IMPL_HPP | |