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concurrentqueue/benchmarks/tbb/concurrent_vector.cpp

632 lines
30 KiB
C++

/*
Copyright 2005-2014 Intel Corporation. All Rights Reserved.
This file is part of Threading Building Blocks. Threading Building Blocks is free software;
you can redistribute it and/or modify it under the terms of the GNU General Public License
version 2 as published by the Free Software Foundation. Threading Building Blocks is
distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the
implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the GNU General Public License for more details. You should have received a copy of
the GNU General Public License along with Threading Building Blocks; if not, write to the
Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
As a special exception, you may use this file as part of a free software library without
restriction. Specifically, if other files instantiate templates or use macros or inline
functions from this file, or you compile this file and link it with other files to produce
an executable, this file does not by itself cause the resulting executable to be covered
by the GNU General Public License. This exception does not however invalidate any other
reasons why the executable file might be covered by the GNU General Public License.
*/
#if (_MSC_VER)
//MSVC 10 "deprecated" application of some std:: algorithms to raw pointers as not safe.
//The reason is that destination is not checked against bounds/having enough place.
#define _SCL_SECURE_NO_WARNINGS
#endif
#include "tbb/concurrent_vector.h"
#include "tbb/cache_aligned_allocator.h"
#include "tbb/tbb_exception.h"
#include "tbb_misc.h"
#include "itt_notify.h"
#if !TBB_USE_EXCEPTIONS && _MSC_VER
// Suppress "C++ exception handler used, but unwind semantics are not enabled" warning in STL headers
#pragma warning (push)
#pragma warning (disable: 4530)
#endif
#include <cstring>
#include <memory> //for uninitialized_fill_n
#if !TBB_USE_EXCEPTIONS && _MSC_VER
#pragma warning (pop)
#endif
#if defined(_MSC_VER) && defined(_Wp64)
// Workaround for overzealous compiler warnings in /Wp64 mode
#pragma warning (disable: 4267)
#endif
using namespace std;
namespace tbb {
namespace internal {
class concurrent_vector_base_v3::helper :no_assign {
public:
//! memory page size
static const size_type page_size = 4096;
inline static bool incompact_predicate(size_type size) { // assert size != 0, see source/test/test_vector_layout.cpp
return size < page_size || ((size-1)%page_size < page_size/2 && size < page_size * 128); // for more details
}
inline static size_type find_segment_end(const concurrent_vector_base_v3 &v) {
segment_t *s = v.my_segment;
segment_index_t u = s==v.my_storage? pointers_per_short_table : pointers_per_long_table;
segment_index_t k = 0;
while( k < u && (s[k].load<relaxed>()==segment_allocated() ))
++k;
return k;
}
// TODO: optimize accesses to my_first_block
//! assign first segment size. k - is index of last segment to be allocated, not a count of segments
inline static void assign_first_segment_if_necessary(concurrent_vector_base_v3 &v, segment_index_t k) {
if( !v.my_first_block ) {
/* There was a suggestion to set first segment according to incompact_predicate:
while( k && !helper::incompact_predicate(segment_size( k ) * element_size) )
--k; // while previous vector size is compact, decrement
// reasons to not do it:
// * constructor(n) is not ready to accept fragmented segments
// * backward compatibility due to that constructor
// * current version gives additional guarantee and faster init.
// * two calls to reserve() will give the same effect.
*/
v.my_first_block.compare_and_swap(k+1, 0); // store number of segments
}
}
inline static void *allocate_segment(concurrent_vector_base_v3 &v, size_type n) {
void *ptr = v.vector_allocator_ptr(v, n);
if(!ptr) throw_exception(eid_bad_alloc); // check for bad allocation, throw exception
return ptr;
}
//! Publish segment so other threads can see it.
template<typename argument_type>
inline static void publish_segment( segment_t& s, argument_type rhs ) {
// see also itt_store_pointer_with_release_v3()
ITT_NOTIFY( sync_releasing, &s );
s.store<release>(rhs);
}
static size_type enable_segment(concurrent_vector_base_v3 &v, size_type k, size_type element_size, bool mark_as_not_used_on_failure = false);
// TODO: rename as get_segments_table() and return segment pointer
inline static void extend_table_if_necessary(concurrent_vector_base_v3 &v, size_type k, size_type start ) {
if(k >= pointers_per_short_table && v.my_segment == v.my_storage)
extend_segment_table(v, start );
}
static void extend_segment_table(concurrent_vector_base_v3 &v, size_type start);
struct segment_not_used_predicate: no_assign {
segment_t &s;
segment_not_used_predicate(segment_t &segment) : s(segment) {}
bool operator()() const { return s.load<relaxed>() == segment_not_used ();}
};
inline static segment_t& acquire_segment(concurrent_vector_base_v3 &v, size_type index, size_type element_size, bool owner) {
segment_t &s = v.my_segment[index]; // TODO: pass v.my_segment as argument
if( s.load<acquire>() == segment_not_used() ) { // do not check for segment_allocation_failed state
if( owner ) {
enable_segment( v, index, element_size );
} else {
ITT_NOTIFY(sync_prepare, &s);
spin_wait_while(segment_not_used_predicate(s));
ITT_NOTIFY(sync_acquired, &s);
}
} else {
ITT_NOTIFY(sync_acquired, &s);
}
if(s.load<relaxed>() != segment_allocated())
throw_exception(eid_bad_last_alloc); // throw custom exception, because it's hard to recover correctly after segment_allocation_failed state
return s;
}
///// non-static fields of helper for exception-safe iteration across segments
segment_t *table;// TODO: review all segment_index_t as just short type
size_type first_block, k, sz, start, finish, element_size;
helper(segment_t *segments, size_type fb, size_type esize, size_type index, size_type s, size_type f) throw()
: table(segments), first_block(fb), k(index), sz(0), start(s), finish(f), element_size(esize) {}
inline void first_segment() throw() {
__TBB_ASSERT( start <= finish, NULL );
__TBB_ASSERT( first_block || !finish, NULL );
if( k < first_block ) k = 0; // process solid segment at a time
size_type base = segment_base( k );
__TBB_ASSERT( base <= start, NULL );
finish -= base; start -= base; // rebase as offsets from segment k
sz = k ? base : segment_size( first_block ); // sz==base for k>0
}
inline void next_segment() throw() {
finish -= sz; start = 0; // offsets from next segment
if( !k ) k = first_block;
else { ++k; sz = segment_size( k ); }
}
template<typename F>
inline size_type apply(const F &func) {
first_segment();
while( sz < finish ) { // work for more than one segment
//TODO: remove extra load() of table[k] inside func
func( table[k], table[k].load<relaxed>().pointer<char>() + element_size*start, sz - start );
next_segment();
}
func( table[k], table[k].load<relaxed>().pointer<char>() + element_size*start, finish - start );
return k;
}
inline segment_value_t get_segment_value(size_type index, bool wait) {
segment_t &s = table[index];
if( wait && (s.load<acquire>() == segment_not_used()) ) {
ITT_NOTIFY(sync_prepare, &s);
spin_wait_while(segment_not_used_predicate(s));
ITT_NOTIFY(sync_acquired, &s);
}
return s.load<relaxed>();
}
~helper() {
if( sz >= finish ) return; // the work is done correctly
cleanup();
}
//! Out of line code to assists destructor in infrequent cases.
void cleanup();
/// TODO: turn into lambda functions when available
struct init_body {
internal_array_op2 func;
const void *arg;
init_body(internal_array_op2 init, const void *src) : func(init), arg(src) {}
void operator()(segment_t &, void *begin, size_type n) const {
func( begin, arg, n );
}
};
struct safe_init_body {
internal_array_op2 func;
const void *arg;
safe_init_body(internal_array_op2 init, const void *src) : func(init), arg(src) {}
void operator()(segment_t &s, void *begin, size_type n) const {
if(s.load<relaxed>() != segment_allocated())
throw_exception(eid_bad_last_alloc); // throw custom exception
func( begin, arg, n );
}
};
struct destroy_body {
internal_array_op1 func;
destroy_body(internal_array_op1 destroy) : func(destroy) {}
void operator()(segment_t &s, void *begin, size_type n) const {
if(s.load<relaxed>() == segment_allocated())
func( begin, n );
}
};
};
void concurrent_vector_base_v3::helper::extend_segment_table(concurrent_vector_base_v3 &v, concurrent_vector_base_v3::size_type start) {
if( start > segment_size(pointers_per_short_table) ) start = segment_size(pointers_per_short_table);
// If other threads are trying to set pointers in the short segment, wait for them to finish their
// assignments before we copy the short segment to the long segment. Note: grow_to_at_least depends on it
for( segment_index_t i = 0; segment_base(i) < start && v.my_segment == v.my_storage; i++ ){
if(v.my_storage[i].load<relaxed>() == segment_not_used()) {
ITT_NOTIFY(sync_prepare, &v.my_storage[i]);
atomic_backoff backoff(true);
while( v.my_segment == v.my_storage && (v.my_storage[i].load<relaxed>() == segment_not_used()) )
backoff.pause();
ITT_NOTIFY(sync_acquired, &v.my_storage[i]);
}
}
if( v.my_segment != v.my_storage ) return;
segment_t* new_segment_table = (segment_t*)NFS_Allocate( pointers_per_long_table, sizeof(segment_t), NULL );
__TBB_ASSERT(new_segment_table, "NFS_Allocate should throws exception if it cannot allocate the requested storage, and not returns zero pointer" );
std::uninitialized_fill_n(new_segment_table,size_t(pointers_per_long_table),segment_t()); //init newly allocated table
//TODO: replace with static assert
__TBB_STATIC_ASSERT(pointers_per_long_table >= pointers_per_short_table, "size of the big table should be not lesser than of the small one, as we copy values to it" );
std::copy(v.my_storage, v.my_storage+pointers_per_short_table, new_segment_table);//copy values from old table, here operator= of segment_t is used
if( v.my_segment.compare_and_swap( new_segment_table, v.my_storage ) != v.my_storage )
NFS_Free( new_segment_table );
// else TODO: add ITT_NOTIFY signals for v.my_segment?
}
concurrent_vector_base_v3::size_type concurrent_vector_base_v3::helper::enable_segment(concurrent_vector_base_v3 &v, concurrent_vector_base_v3::size_type k, concurrent_vector_base_v3::size_type element_size,
bool mark_as_not_used_on_failure ) {
struct segment_scope_guard : no_copy{
segment_t* my_segment_ptr;
bool my_mark_as_not_used;
segment_scope_guard(segment_t& segment, bool mark_as_not_used) : my_segment_ptr(&segment), my_mark_as_not_used(mark_as_not_used){}
void dismiss(){ my_segment_ptr = 0;}
~segment_scope_guard(){
if (my_segment_ptr){
if (!my_mark_as_not_used){
publish_segment(*my_segment_ptr, segment_allocation_failed());
}else{
publish_segment(*my_segment_ptr, segment_not_used());
}
}
}
};
segment_t* s = v.my_segment; // TODO: optimize out as argument? Optimize accesses to my_first_block
__TBB_ASSERT(s[k].load<relaxed>() != segment_allocated(), "concurrent operation during growth?");
size_type size_of_enabled_segment = segment_size(k);
size_type size_to_allocate = size_of_enabled_segment;
if( !k ) {
assign_first_segment_if_necessary(v, default_initial_segments-1);
size_of_enabled_segment = 2 ;
size_to_allocate = segment_size(v.my_first_block);
} else {
spin_wait_while_eq( v.my_first_block, segment_index_t(0) );
}
if( k && (k < v.my_first_block)){ //no need to allocate anything
// s[0].array is changed only once ( 0 -> !0 ) and points to uninitialized memory
segment_value_t array0 = s[0].load<acquire>();
if(array0 == segment_not_used()){
// sync_prepare called only if there is a wait
ITT_NOTIFY(sync_prepare, &s[0]);
spin_wait_while( segment_not_used_predicate(s[0]));
array0 = s[0].load<acquire>();
}
ITT_NOTIFY(sync_acquired, &s[0]);
if(array0 != segment_allocated()) { // check for segment_allocation_failed state of initial segment
publish_segment(s[k], segment_allocation_failed()); // and assign segment_allocation_failed state here
throw_exception(eid_bad_last_alloc); // throw custom exception
}
publish_segment( s[k],
static_cast<void*>(array0.pointer<char>() + segment_base(k)*element_size )
);
} else {
segment_scope_guard k_segment_guard(s[k], mark_as_not_used_on_failure);
publish_segment(s[k], allocate_segment(v, size_to_allocate));
k_segment_guard.dismiss();
}
return size_of_enabled_segment;
}
void concurrent_vector_base_v3::helper::cleanup() {
if( !sz ) { // allocation failed, restore the table
segment_index_t k_start = k, k_end = segment_index_of(finish-1);
if( segment_base( k_start ) < start )
get_segment_value(k_start++, true); // wait
if( k_start < first_block ) {
segment_value_t segment0 = get_segment_value(0, start>0); // wait if necessary
if((segment0 != segment_not_used()) && !k_start ) ++k_start;
if(segment0 != segment_allocated())
for(; k_start < first_block && k_start <= k_end; ++k_start )
publish_segment(table[k_start], segment_allocation_failed());
else for(; k_start < first_block && k_start <= k_end; ++k_start )
publish_segment(table[k_start], static_cast<void*>(
(segment0.pointer<char>()) + segment_base(k_start)*element_size) );
}
for(; k_start <= k_end; ++k_start ) // not in first block
if(table[k_start].load<acquire>() == segment_not_used())
publish_segment(table[k_start], segment_allocation_failed());
// fill allocated items
first_segment();
goto recover;
}
while( sz <= finish ) { // there is still work for at least one segment
next_segment();
recover:
segment_value_t array = table[k].load<relaxed>();
if(array == segment_allocated())
std::memset( (array.pointer<char>()) + element_size*start, 0, ((sz<finish?sz:finish) - start)*element_size );
else __TBB_ASSERT( array == segment_allocation_failed(), NULL );
}
}
concurrent_vector_base_v3::~concurrent_vector_base_v3() {
segment_t* s = my_segment;
if( s != my_storage ) {
#if TBB_USE_ASSERT
//to please assert in segment_t destructor
std::fill_n(my_storage,size_t(pointers_per_short_table),segment_t());
#endif /* TBB_USE_ASSERT */
#if TBB_USE_DEBUG
for( segment_index_t i = 0; i < pointers_per_long_table; i++)
__TBB_ASSERT( my_segment[i].load<relaxed>() != segment_allocated(), "Segment should have been freed. Please recompile with new TBB before using exceptions.");
#endif
my_segment = my_storage;
NFS_Free( s );
}
}
concurrent_vector_base_v3::size_type concurrent_vector_base_v3::internal_capacity() const {
return segment_base( helper::find_segment_end(*this) );
}
void concurrent_vector_base_v3::internal_throw_exception(size_type t) const {
switch(t) {
case 0: throw_exception(eid_out_of_range);
case 1: throw_exception(eid_segment_range_error);
case 2: throw_exception(eid_index_range_error);
}
}
void concurrent_vector_base_v3::internal_reserve( size_type n, size_type element_size, size_type max_size ) {
if( n>max_size )
throw_exception(eid_reservation_length_error);
__TBB_ASSERT( n, NULL );
helper::assign_first_segment_if_necessary(*this, segment_index_of(n-1));
segment_index_t k = helper::find_segment_end(*this);
for( ; segment_base(k)<n; ++k ) {
helper::extend_table_if_necessary(*this, k, 0);
if(my_segment[k].load<relaxed>() != segment_allocated())
helper::enable_segment(*this, k, element_size, true ); //in case of failure mark segments as not used
}
}
//TODO: Looks like atomic loads can be done relaxed here, as the only place this method is called from
//is the constructor, which does not require synchronization (for more details see comment in the
// concurrent_vector_base constructor).
void concurrent_vector_base_v3::internal_copy( const concurrent_vector_base_v3& src, size_type element_size, internal_array_op2 copy ) {
size_type n = src.my_early_size;
__TBB_ASSERT( my_segment == my_storage, NULL);
if( n ) {
helper::assign_first_segment_if_necessary(*this, segment_index_of(n-1));
size_type b;
for( segment_index_t k=0; (b=segment_base(k))<n; ++k ) {
if( (src.my_segment.load<acquire>() == src.my_storage && k >= pointers_per_short_table)
|| (src.my_segment[k].load<relaxed>() != segment_allocated())) {
my_early_size = b; break;
}
helper::extend_table_if_necessary(*this, k, 0);
size_type m = helper::enable_segment(*this, k, element_size);
if( m > n-b ) m = n-b;
my_early_size = b+m;
copy( my_segment[k].load<relaxed>().pointer<void>(), src.my_segment[k].load<relaxed>().pointer<void>(), m );
}
}
}
void concurrent_vector_base_v3::internal_assign( const concurrent_vector_base_v3& src, size_type element_size, internal_array_op1 destroy, internal_array_op2 assign, internal_array_op2 copy ) {
size_type n = src.my_early_size;
while( my_early_size>n ) { // TODO: improve
segment_index_t k = segment_index_of( my_early_size-1 );
size_type b=segment_base(k);
size_type new_end = b>=n ? b : n;
__TBB_ASSERT( my_early_size>new_end, NULL );
if( my_segment[k].load<relaxed>() != segment_allocated()) // check vector was broken before
throw_exception(eid_bad_last_alloc); // throw custom exception
// destructors are supposed to not throw any exceptions
destroy( my_segment[k].load<relaxed>().pointer<char>() + element_size*(new_end-b), my_early_size-new_end );
my_early_size = new_end;
}
size_type dst_initialized_size = my_early_size;
my_early_size = n;
helper::assign_first_segment_if_necessary(*this, segment_index_of(n));
size_type b;
for( segment_index_t k=0; (b=segment_base(k))<n; ++k ) {
if( (src.my_segment.load<acquire>() == src.my_storage && k >= pointers_per_short_table)
|| src.my_segment[k].load<relaxed>() != segment_allocated() ) { // if source is damaged
my_early_size = b; break; // TODO: it may cause undestructed items
}
helper::extend_table_if_necessary(*this, k, 0);
if( my_segment[k].load<relaxed>() == segment_not_used())
helper::enable_segment(*this, k, element_size);
else if( my_segment[k].load<relaxed>() != segment_allocated() )
throw_exception(eid_bad_last_alloc); // throw custom exception
size_type m = k? segment_size(k) : 2;
if( m > n-b ) m = n-b;
size_type a = 0;
if( dst_initialized_size>b ) {
a = dst_initialized_size-b;
if( a>m ) a = m;
assign( my_segment[k].load<relaxed>().pointer<void>(), src.my_segment[k].load<relaxed>().pointer<void>(), a );
m -= a;
a *= element_size;
}
if( m>0 )
copy( my_segment[k].load<relaxed>().pointer<char>() + a, src.my_segment[k].load<relaxed>().pointer<char>() + a, m );
}
__TBB_ASSERT( src.my_early_size==n, "detected use of concurrent_vector::operator= with right side that was concurrently modified" );
}
void* concurrent_vector_base_v3::internal_push_back( size_type element_size, size_type& index ) {
__TBB_ASSERT( sizeof(my_early_size)==sizeof(uintptr_t), NULL );
size_type tmp = my_early_size.fetch_and_increment<acquire>();
index = tmp;
segment_index_t k_old = segment_index_of( tmp );
size_type base = segment_base(k_old);
helper::extend_table_if_necessary(*this, k_old, tmp);
segment_t& s = helper::acquire_segment(*this, k_old, element_size, base==tmp);
size_type j_begin = tmp-base;
return (void*)(s.load<relaxed>().pointer<char>() + element_size*j_begin);
}
void concurrent_vector_base_v3::internal_grow_to_at_least( size_type new_size, size_type element_size, internal_array_op2 init, const void *src ) {
internal_grow_to_at_least_with_result( new_size, element_size, init, src );
}
concurrent_vector_base_v3::size_type concurrent_vector_base_v3::internal_grow_to_at_least_with_result( size_type new_size, size_type element_size, internal_array_op2 init, const void *src ) {
size_type e = my_early_size;
while( e<new_size ) {
size_type f = my_early_size.compare_and_swap(new_size,e);
if( f==e ) {
internal_grow( e, new_size, element_size, init, src );
break;
}
e = f;
}
// Check/wait for segments allocation completes
segment_index_t i, k_old = segment_index_of( new_size-1 );
if( k_old >= pointers_per_short_table && my_segment == my_storage ) {
spin_wait_while_eq( my_segment, my_storage );
}
for( i = 0; i <= k_old; ++i ) {
segment_t &s = my_segment[i];
if(s.load<relaxed>() == segment_not_used()) {
ITT_NOTIFY(sync_prepare, &s);
atomic_backoff backoff(true);
while( my_segment[i].load<acquire>() == segment_not_used() ) // my_segment may change concurrently
backoff.pause();
ITT_NOTIFY(sync_acquired, &s);
}
if( my_segment[i].load<relaxed>() != segment_allocated() )
throw_exception(eid_bad_last_alloc);
}
#if TBB_USE_DEBUG
size_type capacity = internal_capacity();
__TBB_ASSERT( capacity >= new_size, NULL);
#endif
return e;
}
concurrent_vector_base_v3::size_type concurrent_vector_base_v3::internal_grow_by( size_type delta, size_type element_size, internal_array_op2 init, const void *src ) {
size_type result = my_early_size.fetch_and_add(delta);
internal_grow( result, result+delta, element_size, init, src );
return result;
}
void concurrent_vector_base_v3::internal_grow( const size_type start, size_type finish, size_type element_size, internal_array_op2 init, const void *src ) {
__TBB_ASSERT( start<finish, "start must be less than finish" );
segment_index_t k_start = segment_index_of(start), k_end = segment_index_of(finish-1);
helper::assign_first_segment_if_necessary(*this, k_end);
helper::extend_table_if_necessary(*this, k_end, start);
helper range(my_segment, my_first_block, element_size, k_start, start, finish);
for(; k_end > k_start && k_end >= range.first_block; --k_end ) // allocate segments in reverse order
helper::acquire_segment(*this, k_end, element_size, true/*for k_end>k_start*/);
for(; k_start <= k_end; ++k_start ) // but allocate first block in straight order
helper::acquire_segment(*this, k_start, element_size, segment_base( k_start ) >= start );
range.apply( helper::init_body(init, src) );
}
void concurrent_vector_base_v3::internal_resize( size_type n, size_type element_size, size_type max_size, const void *src,
internal_array_op1 destroy, internal_array_op2 init ) {
size_type j = my_early_size;
if( n > j ) { // construct items
internal_reserve(n, element_size, max_size);
my_early_size = n;
helper for_each(my_segment, my_first_block, element_size, segment_index_of(j), j, n);
for_each.apply( helper::safe_init_body(init, src) );
} else {
my_early_size = n;
helper for_each(my_segment, my_first_block, element_size, segment_index_of(n), n, j);
for_each.apply( helper::destroy_body(destroy) );
}
}
concurrent_vector_base_v3::segment_index_t concurrent_vector_base_v3::internal_clear( internal_array_op1 destroy ) {
__TBB_ASSERT( my_segment, NULL );
size_type j = my_early_size;
my_early_size = 0;
helper for_each(my_segment, my_first_block, 0, 0, 0, j); // element_size is safe to be zero if 'start' is zero
j = for_each.apply( helper::destroy_body(destroy) );
size_type i = helper::find_segment_end(*this);
return j < i? i : j+1;
}
void *concurrent_vector_base_v3::internal_compact( size_type element_size, void *table, internal_array_op1 destroy, internal_array_op2 copy )
{
const size_type my_size = my_early_size;
const segment_index_t k_end = helper::find_segment_end(*this); // allocated segments
const segment_index_t k_stop = my_size? segment_index_of(my_size-1) + 1 : 0; // number of segments to store existing items: 0=>0; 1,2=>1; 3,4=>2; [5-8]=>3;..
const segment_index_t first_block = my_first_block; // number of merged segments, getting values from atomics
segment_index_t k = first_block;
if(k_stop < first_block)
k = k_stop;
else
while (k < k_stop && helper::incompact_predicate(segment_size( k ) * element_size) ) k++;
if(k_stop == k_end && k == first_block)
return NULL;
segment_t *const segment_table = my_segment;
internal_segments_table &old = *static_cast<internal_segments_table*>( table );
//this call is left here for sake of backward compatibility, and as a placeholder for table initialization
std::fill_n(old.table,sizeof(old.table)/sizeof(old.table[0]),segment_t());
old.first_block=0;
if ( k != first_block && k ) // first segment optimization
{
// exception can occur here
void *seg = helper::allocate_segment(*this, segment_size(k));
old.table[0].store<relaxed>(seg);
old.first_block = k; // fill info for freeing new segment if exception occurs
// copy items to the new segment
size_type my_segment_size = segment_size( first_block );
for (segment_index_t i = 0, j = 0; i < k && j < my_size; j = my_segment_size) {
__TBB_ASSERT( segment_table[i].load<relaxed>() == segment_allocated(), NULL);
void *s = static_cast<void*>(
static_cast<char*>(seg) + segment_base(i)*element_size );
//TODO: refactor to use std::min
if(j + my_segment_size >= my_size) my_segment_size = my_size - j;
__TBB_TRY { // exception can occur here
copy( s, segment_table[i].load<relaxed>().pointer<void>(), my_segment_size );
} __TBB_CATCH(...) { // destroy all the already copied items
helper for_each(&old.table[0], old.first_block, element_size,
0, 0, segment_base(i)+ my_segment_size);
for_each.apply( helper::destroy_body(destroy) );
__TBB_RETHROW();
}
my_segment_size = i? segment_size( ++i ) : segment_size( i = first_block );
}
// commit the changes
std::copy(segment_table,segment_table + k,old.table);
for (segment_index_t i = 0; i < k; i++) {
segment_table[i].store<relaxed>(static_cast<void*>(
static_cast<char*>(seg) + segment_base(i)*element_size ));
}
old.first_block = first_block; my_first_block = k; // now, first_block != my_first_block
// destroy original copies
my_segment_size = segment_size( first_block ); // old.first_block actually
for (segment_index_t i = 0, j = 0; i < k && j < my_size; j = my_segment_size) {
if(j + my_segment_size >= my_size) my_segment_size = my_size - j;
// destructors are supposed to not throw any exceptions
destroy( old.table[i].load<relaxed>().pointer<void>(), my_segment_size );
my_segment_size = i? segment_size( ++i ) : segment_size( i = first_block );
}
}
// free unnecessary segments allocated by reserve() call
if ( k_stop < k_end ) {
old.first_block = first_block;
std::copy(segment_table+k_stop, segment_table+k_end, old.table+k_stop );
std::fill_n(segment_table+k_stop, (k_end-k_stop), segment_t());
if( !k ) my_first_block = 0;
}
return table;
}
void concurrent_vector_base_v3::internal_swap(concurrent_vector_base_v3& v)
{
size_type my_sz = my_early_size.load<acquire>();
size_type v_sz = v.my_early_size.load<relaxed>();
if(!my_sz && !v_sz) return;
bool my_was_short = (my_segment.load<relaxed>() == my_storage);
bool v_was_short = (v.my_segment.load<relaxed>() == v.my_storage);
//In C++11, this would be: swap(my_storage, v.my_storage);
for (int i=0; i < pointers_per_short_table; ++i){
swap(my_storage[i], v.my_storage[i]);
}
tbb::internal::swap<relaxed>(my_first_block, v.my_first_block);
tbb::internal::swap<relaxed>(my_segment, v.my_segment);
if (my_was_short){
v.my_segment.store<relaxed>(v.my_storage);
}
if(v_was_short){
my_segment.store<relaxed>(my_storage);
}
my_early_size.store<relaxed>(v_sz);
v.my_early_size.store<release>(my_sz);
}
} // namespace internal
} // tbb