sample6.cpp

This example demonstrates using of custom memory allocators.

This example demonstrates using of custom memory allocators.In this case allocator works as a memory checker, counts number of allocations and deallocations to make sure that there is no memory leaks.

/*
Copyright(c) 2002-2017 Anatoliy Kuznetsov(anatoliy_kuznetsov at yahoo.com)
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.
For more information please visit: http://bitmagic.io
*/
/** \example sample6.cpp
This example demonstrates using of custom memory allocators.
In this case allocator works as a memory checker, counts number of
allocations and deallocations to make sure that there is no memory leaks.
*/
/*! \file sample6.cpp
\brief Example: bvector<> custom memory allocator
*/
#include <iostream>
#include <cassert>
#include "bm.h"
#include "bmundef.h" /* clear the pre-proc defines from BM */
using namespace std;
// Custom allocator keeps number of all alloc/free calls.
// It also reservs the front word of the allocated block and saves
// number of elements allocated. On deallocation it makes sure
// it deallocates the same size as allocated
//
// Please note, that this sample allocator is NOT compatible with SIMD
// optimizations, requiring special address alignment
//
class dbg_block_allocator
{
public:
static unsigned na_;
static unsigned nf_;
static bm::word_t* allocate(size_t n, const void *)
{
++na_;
assert(n);
bm::word_t* p =
(bm::word_t*) ::malloc((n+1) * sizeof(bm::word_t));
*p = (unsigned)n;
return ++p;
}
static void deallocate(bm::word_t* p, size_t /* n */)
{
++nf_;
--p;
::free(p);
}
static int balance()
{
return int(nf_ - na_);
}
};
unsigned dbg_block_allocator::na_ = 0;
unsigned dbg_block_allocator::nf_ = 0;
class dbg_ptr_allocator
{
public:
static unsigned na_;
static unsigned nf_;
static void* allocate(size_t n, const void *)
{
++na_;
assert(sizeof(size_t) == sizeof(void*));
void* p = ::malloc((n+1) * sizeof(void*));
size_t* s = (size_t*) p;
*s = n;
return (void*)++s;
}
static void deallocate(void* p, size_t /* n */)
{
++nf_;
size_t* s = (size_t*) p;
--s;
::free(s);
}
static int balance()
{
return int(nf_ - na_);
}
};
unsigned dbg_ptr_allocator::na_ = 0;
unsigned dbg_ptr_allocator::nf_ = 0;
typedef
bm::mem_alloc<dbg_block_allocator, dbg_ptr_allocator,
bm::alloc_pool<dbg_block_allocator, dbg_ptr_allocator>> dbg_alloc;
typedef bm::bvector<dbg_alloc> bvect;
int main(void)
{
try
{
{
bvect bv;
bv[10] = true;
bv[100000] = true;
bv[10000000] = false;
}
cout << "Number of BLOCK allocations = " << dbg_block_allocator::na_ << endl;
cout << "Number of PTR allocations = " << dbg_ptr_allocator::na_ << endl;
}
catch(std::exception& ex)
{
std::cerr << ex.what() << std::endl;
return 1;
}
assert(dbg_block_allocator::balance() == 0);
assert(dbg_ptr_allocator::balance() == 0);
return 0;
}
bm.h
Compressed bit-vector bvector<> container, set algebraic methods, traversal iterators.
bmundef.h
pre-processor un-defines to avoid global space pollution (internal)
bm::alloc_pool
Allocation pool object.
Definition bmalloc.h:223
bm::bvector
Bitvector Bit-vector container with runtime compression of bits.
Definition bm.h:115
bm::mem_alloc
BM style allocator adapter.
Definition bmalloc.h:290
dbg_block_allocator
Definition sample6.cpp:46
dbg_block_allocator::na_
static unsigned na_
Definition sample6.cpp:48
dbg_block_allocator::balance
static int balance()
Definition sample6.cpp:68
dbg_block_allocator::allocate
static bm::word_t * allocate(size_t n, const void *)
Definition sample6.cpp:51
dbg_block_allocator::nf_
static unsigned nf_
Definition sample6.cpp:49
dbg_block_allocator::deallocate
static void deallocate(bm::word_t *p, size_t)
Definition sample6.cpp:61
dbg_ptr_allocator
Definition sample6.cpp:78
dbg_ptr_allocator::na_
static unsigned na_
Definition sample6.cpp:80
dbg_ptr_allocator::balance
static int balance()
Definition sample6.cpp:101
dbg_ptr_allocator::deallocate
static void deallocate(void *p, size_t)
Definition sample6.cpp:93
dbg_ptr_allocator::allocate
static void * allocate(size_t n, const void *)
Definition sample6.cpp:83
dbg_ptr_allocator::nf_
static unsigned nf_
Definition sample6.cpp:81
bm::word_t
unsigned int word_t
Definition bmconst.h:39
main
int main(void)
Definition sample1.cpp:43
bvect
bm::bvector< dbg_alloc > bvect
Definition sample6.cpp:116
dbg_alloc
bm::mem_alloc< dbg_block_allocator, dbg_ptr_allocator, bm::alloc_pool< dbg_block_allocator, dbg_ptr_allocator > > dbg_alloc
Definition sample6.cpp:114