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#ifndef _RHEOLEF_STACK_ALLOCATOR_H
#define _RHEOLEF_STACK_ALLOCATOR_H
///
/// This file is part of Rheolef.
///
/// Copyright (C) 2000-2009 Pierre Saramito <Pierre.Saramito@imag.fr>
///
/// Rheolef is free software; you can redistribute it and/or modify
/// it under the terms of the GNU General Public License as published by
/// the Free Software Foundation; either version 2 of the License, or
/// (at your option) any later version.
///
/// Rheolef 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 Rheolef; if not, write to the Free Software
/// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
///
/// =========================================================================
/**
* @file stack_allocator - stack-based allocator
*/
#include <memory>
#include <limits>
#include "rheolef/compiler.h"
#include "rheolef/pretty_name.h"
namespace rheolef {
/*Class:stack_allocator
EXAMPLE:
@example
const size_t stack_size = 1024;
vector<unsigned char> stack (stack_size);
stack_allocator<double> stack_alloc (stack.begin().operator->(), stack.size());
typedef map <size_t, double, less<size_t>, stack_allocator<pair<size_t,double> > > map_type;
map_type a (less<size_t>(), stack_alloc);
a.insert (make_pair (0, 3.14));
a.insert (make_pair (1, 1.17));
for (map_type::iterator iter = a.begin(), last = a.end(); iter != last; iter++) @{
cout << (*iter).first << " " << (*iter).second << endl;
@}
@end example
End:
*/
//<begin_verbatim:
template <typename T>
class stack_allocator {
protected:
struct handler_type; // forward declaration:
public:
// typedefs:
typedef size_t size_type;
typedef std::ptrdiff_t difference_type;
typedef T* pointer;
typedef const T* const_pointer;
typedef T& reference;
typedef const T& const_reference;
typedef T value_type;
// constructors:
stack_allocator() throw()
: handler (new handler_type)
{
}
stack_allocator (unsigned char* stack, size_t stack_size) throw()
: handler (new handler_type (stack, stack_size))
{
trace_macro ("stack_allocator cstor");
}
stack_allocator (const stack_allocator& sa) throw()
: handler (sa.handler)
{
++handler->reference_count;
}
template <typename U>
stack_allocator (const stack_allocator<U>& sa) throw()
: handler ((typename stack_allocator<T>::handler_type*)(sa.handler))
{
++handler->reference_count;
}
~stack_allocator() throw()
{
trace_macro ("stack_allocator dstor");
check_macro (handler != NULL, "unexpected null mem_info");
if (--handler->reference_count == 0) delete handler;
}
// Rebind to allocators of other types
template <typename U>
struct rebind {
typedef stack_allocator<U> other;
};
// assignment:
stack_allocator& operator= (const stack_allocator& sa)
{
handler = sa.handler;
++handler->reference_count;
return *this;
}
// utility functions:
pointer address (reference r) const { return &r; }
const_pointer address (const_reference c) const { return &c; }
size_type max_size() const { return std::numeric_limits<size_t>::max() / sizeof(T); }
// in-place construction/destruction
void construct (pointer p, const_reference c)
{
// placement new operator:
new( reinterpret_cast<void*>(p) ) T(c);
}
// C++ 2011: default construct a value of type T at the location referenced by p
void construct (pointer p) { new ( reinterpret_cast<void*>(p) ) T(); }
void destroy (pointer p)
{
// call destructor directly:
(p)->~T();
}
// allocate raw memory
pointer allocate (size_type n, const void* = NULL)
{
trace_macro ("allocate "<<n<<" type " << typename_macro(T));
check_macro (handler->stack != NULL, "unexpected null stack");
void* p = handler->stack + handler->allocated_size;
handler->allocated_size += n*sizeof(T);
if (handler->allocated_size + 1 > handler->max_size) {
trace_macro ("stack is full: throwing...");
throw std::bad_alloc();
}
return pointer (p);
}
void deallocate (pointer p, size_type n)
{
trace_macro ("deallocate "<<n<<" type "<<typename_macro(T));
// No need to free stack memory
}
const handler_type* get_handler() const {
return handler;
}
// data:
protected:
struct handler_type {
unsigned char* stack;
size_t allocated_size;
size_t max_size;
size_t reference_count;
handler_type()
: stack (NULL),
allocated_size (0),
max_size (0),
reference_count (1)
{
trace_macro ("stack_allocator::mem_info cstor NULL");
}
handler_type (unsigned char* stack1, size_t size1)
: stack (stack1),
allocated_size (0),
max_size (size1),
reference_count (1)
{
trace_macro ("stack_allocator::mem_info cstori: size="<<max_size);
}
~handler_type()
{
trace_macro ("stack_allocator::mem_info dstor: size="<<max_size);
}
private:
handler_type (const handler_type&);
handler_type& operator= (const handler_type&);
};
handler_type* handler;
template <typename U> friend class stack_allocator;
};
// Comparison
template <typename T1>
bool operator==( const stack_allocator<T1>& lhs, const stack_allocator<T1>& rhs) throw()
{
return lhs.get_handler() == rhs.get_handler();
}
template <typename T1>
bool operator!=( const stack_allocator<T1>& lhs, const stack_allocator<T1>& rhs) throw()
{
return lhs.get_handler() != rhs.get_handler();
}
//>end_verbatim:
} // namespace rheolef
#endif // STACK_ALLOCATOR_H
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