// Copyright (C) 2004 Davis E. King (davis@dlib.net)
// License: Boost Software License See LICENSE.txt for the full license.
#ifndef DLIB_MEMORY_MANAGER_KERNEl_3_
#define DLIB_MEMORY_MANAGER_KERNEl_3_
#include "../algs.h"
#include "memory_manager_kernel_abstract.h"
#include "../assert.h"
#include <new>
#include "memory_manager_kernel_2.h"
#include "../binary_search_tree/binary_search_tree_kernel_2.h"
namespace dlib
{
template <
typename T,
unsigned long chunk_size
>
class memory_manager_kernel_3
{
/*!
INITIAL VALUE
allocations == 0
next == 0
first_chunk == 0
bst_of_arrays == 0
REQUIREMENTS ON chunk_size
chunk_size is the number of items of type T we will allocate at a time. so
it must be > 0.
CONVENTION
This memory manager implementation allocates memory in blocks of chunk_size*sizeof(T)
bytes. All the sizeof(T) subblocks are kept in a linked list of free memory blocks
and are given out whenever an allocation request occurs. Also, memory is not freed
until this object is destructed.
allocations == get_number_of_allocations()
- if (next != 0) then
- next == the next pointer to return from allocate()
and next == pointer to the first node in a linked list. each node
is one item in the memory pool.
- the last node in the linked list has next set to 0
- else
- we need to call new to get the next pointer to return from allocate()
- if (arrays != 0) then
- someone has called allocate_array()
- (*arrays)[size] == an array of size bytes of memory
- if (first_chunk != 0) then
- first_chunk == the first node in a linked list that contains pointers
to all the chunks we have ever allocated. The last link in the list
has its next pointer set to 0.
!*/
union node
{
node* next;
char item[sizeof(T)];
};
struct chunk_node
{
node* chunk;
chunk_node* next;
};
typedef binary_search_tree_kernel_2<
size_t,
char*,
memory_manager_kernel_2<char,5>
> bst_of_arrays;
public:
typedef T type;
template <typename U>
struct rebind {
typedef memory_manager_kernel_3<U,chunk_size> other;
};
memory_manager_kernel_3(
) :
allocations(0),
next(0),
first_chunk(0),
arrays(0)
{
// You FOOL! You can't have a zero chunk_size.
COMPILE_TIME_ASSERT(chunk_size > 0);
}
virtual ~memory_manager_kernel_3(
)
{
if (allocations == 0)
{
while (first_chunk != 0)
{
chunk_node* temp = first_chunk;
first_chunk = first_chunk->next;
// delete the memory chunk
::operator delete ( static_cast<void*>(temp->chunk));
// delete the chunk_node
delete temp;
}
}
if (arrays)
{
arrays->reset();
while (arrays->move_next())
{
::operator delete (arrays->element().value());
}
delete arrays;
}
}
unsigned long get_number_of_allocations (
) const { return allocations; }
T* allocate_array (
unsigned long size
)
{
size_t block_size = sizeof(T)*size + sizeof(size_t)*2;
// make sure we have initialized the arrays object.
if (arrays == 0)
{
arrays = new bst_of_arrays;
}
char* temp;
// see if we have a suitable block of memory already.
arrays->position_enumerator(block_size);
if (arrays->current_element_valid())
{
// we have a suitable block of memory already so use that one.
arrays->remove_current_element(block_size,temp);
}
else
{
temp = static_cast<char*>(::operator new(block_size));
}
reinterpret_cast<size_t*>(temp)[0] = block_size;
reinterpret_cast<size_t*>(temp)[1] = size;
temp += sizeof(size_t)*2;
try
{
initialize_array(reinterpret_cast<T*>(temp),size);
}
catch (...)
{
// something was thrown while we were initializing the array so
// stick our memory block into arrays and rethrow the exception
temp -= sizeof(size_t)*2;
arrays->add(block_size,temp);
throw;
}
++allocations;
return reinterpret_cast<T*>(temp);
}
void deallocate_array (
T* item
)
{
char* temp = reinterpret_cast<char*>(item);
temp -= sizeof(size_t)*2;
size_t block_size = reinterpret_cast<size_t*>(temp)[0];
size_t size = reinterpret_cast<size_t*>(temp)[1];
deinitialize_array(item,size);
arrays->add(block_size,temp);
--allocations;
}
T* allocate (
)
{
T* temp;
if (next != 0)
{
temp = reinterpret_cast<T*>(next);
node* n = next->next;
try
{
// construct this new T object with placement new.
new (static_cast<void*>(temp))T();
}
catch (...)
{
next->next = n;
throw;
}
next = n;
}
else
{
// the linked list is empty so we need to allocate some more memory
node* block = static_cast<node*>(::operator new (sizeof(node)*chunk_size));
// the first part of this block can be our new object
temp = reinterpret_cast<T*>(block);
try
{
// construct this new T object with placement new.
new (static_cast<void*>(temp))T();
}
catch (...)
{
// construction of the new object threw so delete the block of memory
::operator delete ( static_cast<void*>(block));
throw;
}
// allocate a new chunk_node
chunk_node* chunk;
try {chunk = new chunk_node; }
catch (...)
{
temp->~T();
::operator delete ( static_cast<void*>(block));
throw;
}
// add this block into the chunk list
chunk->chunk = block;
chunk->next = first_chunk;
first_chunk = chunk;
++block;
// now add the rest of the block into the linked list of free nodes.
for (unsigned long i = 0; i < chunk_size-1; ++i)
{
block->next = next;
next = block;
++block;
}
}
++allocations;
return temp;
}
void deallocate (
T* item
)
{
--allocations;
item->~T();
// add this memory into our linked list.
node* temp = reinterpret_cast<node*>(item);
temp->next = next;
next = temp;
}
void swap (
memory_manager_kernel_3& item
)
{
exchange(allocations,item.allocations);
exchange(next,item.next);
exchange(first_chunk,item.first_chunk);
exchange(arrays,item.arrays);
}
private:
// data members
unsigned long allocations;
node* next;
chunk_node* first_chunk;
bst_of_arrays* arrays;
void initialize_array (
T* array,
size_t size
) const
{
size_t i;
try
{
for (i = 0; i < size; ++i)
{
// construct this new T object with placement new.
new (static_cast<void*>(array+i))T();
}
}
catch (...)
{
// Catch any exceptions thrown during the construction process
// and then destruct any T objects that actually were successfully
// constructed.
for (size_t j = 0; j < i; ++j)
{
array[i].~T();
}
throw;
}
}
void deinitialize_array (
T* array,
size_t size
) const
{
for (size_t i = 0; i < size; ++i)
{
array[i].~T();
}
}
// don't do any initialization for the built in types
void initialize_array(unsigned char*, size_t) {}
void deinitialize_array(unsigned char*, size_t) {}
void initialize_array(signed char*, size_t) {}
void deinitialize_array(signed char*, size_t) {}
void initialize_array(char*, size_t) {}
void deinitialize_array(char*, size_t) {}
void initialize_array(int*, size_t) {}
void deinitialize_array(int*, size_t) {}
void initialize_array(unsigned int*, size_t) {}
void deinitialize_array(unsigned int*, size_t) {}
void initialize_array(unsigned long*, size_t) {}
void deinitialize_array(unsigned long*, size_t) {}
void initialize_array(long*, size_t) {}
void deinitialize_array(long*, size_t) {}
void initialize_array(float*, size_t) {}
void deinitialize_array(float*, size_t) {}
void initialize_array(double*, size_t) {}
void deinitialize_array(double*, size_t) {}
void initialize_array(short*, size_t) {}
void deinitialize_array(short*, size_t) {}
void initialize_array(unsigned short*, size_t) {}
void deinitialize_array(unsigned short*, size_t) {}
// restricted functions
memory_manager_kernel_3(memory_manager_kernel_3&); // copy constructor
memory_manager_kernel_3& operator=(memory_manager_kernel_3&); // assignment operator
};
template <
typename T,
unsigned long chunk_size
>
inline void swap (
memory_manager_kernel_3<T,chunk_size>& a,
memory_manager_kernel_3<T,chunk_size>& b
) { a.swap(b); }
// ----------------------------------------------------------------------------------------
}
#endif // DLIB_MEMORY_MANAGER_KERNEl_3_