BitMagic-C++: sample6.cpp

BitMagic-C++

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.

/*
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"
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;
}
dbg_block_allocator::balance
static int balance()
Definition: sample6.cpp:66
dbg_ptr_allocator
Definition: sample6.cpp:75
bm::alloc_pool
Allocation pool object.
Definition: bmalloc.h:200
dbg_ptr_allocator::na_
static unsigned na_
Definition: sample6.cpp:78
bm::bvector
Bitvector Bit-vector container with runtime compression of bits.
Definition: bm.h:107
dbg_block_allocator::nf_
static unsigned nf_
Definition: sample6.cpp:47
dbg_ptr_allocator::balance
static int balance()
Definition: sample6.cpp:99
dbg_ptr_allocator::nf_
static unsigned nf_
Definition: sample6.cpp:79
dbg_block_allocator
Definition: sample6.cpp:43
main
int main(void)
Definition: sample6.cpp:116
bm::word_t
unsigned int word_t
Definition: bmconst.h:38
dbg_block_allocator::na_
static unsigned na_
Definition: sample6.cpp:46
bvect
bm::bvector< dbg_alloc > bvect
Definition: sample6.cpp:114
bm.h
Compressed bit-vector bvector<> container, set algebraic methods, traversal iterators.
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:112
bm::mem_alloc
BM style allocator adapter.
Definition: bmalloc.h:254