/*
* GNU MP Memory Handlers
* (C) 1999-2010 Jack Lloyd
*
* Distributed under the terms of the Botan license
*/

#include <botan/internal/gnump_engine.h>
#include <cstring>
#include <atomic>
#include <gmp.h>

namespace Botan {

namespace {

/*
* For keeping track of existing GMP_Engines and only
* resetting the memory when none are in use.
*/
std::atomic<size_t> gmp_alloc_refcnt(0);

/*
* Allocation Function for GNU MP
*/
void* gmp_malloc(size_t n)
   {
   // Maintain alignment, mlock goes for sizeof(T) alignment
   if(n % 8 == 0)
      return secure_allocator<u64bit>().allocate(n / 8);
   else if(n % 4 == 0)
      return secure_allocator<u32bit>().allocate(n / 4);
   else if(n % 2 == 0)
      return secure_allocator<u16bit>().allocate(n / 2);

   return secure_allocator<byte>().allocate(n);
   }

/*
* Deallocation Function for GNU MP
*/
void gmp_free(void* ptr, size_t n)
   {
   secure_allocator<byte>().deallocate(static_cast<byte*>(ptr), n);
   }

/*
* Reallocation Function for GNU MP
*/
void* gmp_realloc(void* ptr, size_t old_n, size_t new_n)
   {
   void* new_buf = gmp_malloc(new_n);
   std::memcpy(new_buf, ptr, std::min(old_n, new_n));
   gmp_free(ptr, old_n);
   return new_buf;
   }

}

/*
* GMP_Engine Constructor
*/
GMP_Engine::GMP_Engine()
   {
   /*
   if(gmp_alloc_refcnt == 0)
      mp_set_memory_functions(gmp_malloc, gmp_realloc, gmp_free);

   gmp_alloc_refcnt++;
   */
   }

GMP_Engine::~GMP_Engine()
   {
   /*
   --gmp_alloc_refcnt;

   if(gmp_alloc_refcnt == 0)
      mp_set_memory_functions(NULL, NULL, NULL);
   */
   }

}