/*@@
  @file      MaskUtils.c
  @date      October 2002
  @author    Denis Pollney
  @desc
             Utilities for registering/setting/checking the mask.
  @desc
  @version   $Header$
@@*/

#include <stdio.h>

#include "cctk.h"
#include "cctk_FortranString.h"

#include "SpaceMask.h"

static const char* rcsid = "$Header$";

CCTK_FILEVERSION(CACTUSEINSTEIN_SPACEMASK_MaskUtils_c);

SpaceMask_Registry* spacemask_registry = NULL;

/*@@
  @routine    SpaceMask_get_bit_nbr
  @author     Denis Pollney
  @date       15 October 2002
  @desc 
              Return the number of bits required to represent a given number.
	      Cheesy divide-by-two method, maybe something else is quicker.
  @enddesc 
@@*/
 
int
SpaceMask_get_bit_nbr(int nstates)
{
  int bstates;
  int bit_nbr;

  bstates = nstates-1;

  for (bit_nbr=0; bstates>0; ++bit_nbr)
    bstates /= 2;

  return bit_nbr;
}

/*@@
  @routine    SpaceMask_get_free_bits
  @author     Denis Pollney
  @date       15 October 2002
  @desc 
              Determine the mask bits which have not yet been allocated.
	      The return value is a bitmask with the requested number of
	      free bits set to 1. If there are not enough free bits left
	      to satisfy the request, stop with an error.
  @enddesc 
@@*/

CCTK_INT8
SpaceMask_get_free_bits(int nbits)
{
  CCTK_INT8 used_bits;
  CCTK_INT8 new_bits;
  int i;
  int j;
  int n;

  used_bits = 0;
  if (spacemask_registry != NULL)
    {
      for (i=0; i<spacemask_registry->ntypes; ++i)
	used_bits |= spacemask_registry->type_list[i]->bitmask;
    }

  n=1;
  new_bits = 0;
  j = 0;
  for (i=0; i<sizeof(CCTK_INT8)*8 & j<nbits; ++i)
    {
      if (!(n & used_bits))
	{
	  ++j;
	  new_bits |= n;
	}
      n *= 2;
    }

  if (j<nbits)
    CCTK_WARN (0, "Cannot allocate mask: Not enough free bits.");

  return new_bits;
}

/*@@
  @routine    SpaceMask_determine_state_mask
  @author     Denis Pollney
  @date       15 October 2002
  @desc 
              Determine appropriate bitmasks to represent a number of
	      states, using the allocated bit mask.
	      That is, if allocated_bits is set to 00111000, then
	      the returned list of states are permutations of the three
	      non-zero (active) bits.
  @enddesc 
@@*/

CCTK_INT8*
SpaceMask_determine_state_mask(CCTK_INT8 allocated_bits, int nstates)
{
  CCTK_INT8* state_mask;
  int n;
  int bit;
  int i;
  int j;

  state_mask =
    (CCTK_INT8*) malloc (nstates*sizeof(CCTK_INT8));

  for (j=0; j<nstates; ++j)
    state_mask[j] = 0;

  n=1;
  bit=1;

  for (i=0; i<sizeof(CCTK_INT8)*8; ++i)
    {
      if (n & allocated_bits)
	{
	  for (j=0; j<nstates; ++j)
	    {
	      if (bit & j)
		state_mask[j] += n;
	    }
	  bit *= 2;
	}
      n *= 2;
    }

  return state_mask;
}

/*@@
  @routine    SpaceMask_setup_new_state
  @author     Denis Pollney
  @date       15 October 2002
  @desc 
              Allocate a new SpaceMask_State, giving it a name and
	      a bit mask.
  @enddesc 
@@*/

SpaceMask_State*
SpaceMask_setup_new_state(CCTK_INT8 state_mask, char* name)
{
  SpaceMask_State* new_state;

  new_state = (SpaceMask_State*) malloc (sizeof(SpaceMask_State));
  new_state->name = name;
  new_state->bitmask = state_mask;

  return new_state;
}

/*@@
  @routine    SpaceMask_setup_new_type
  @author     Denis Pollney
  @date       15 October 2002
  @desc 
              Allocate a new SpaceMask_Type. This involves allocating
	      a set of bits within the mask to the new type, and creating
	      appropriate bitmasks (using the allocated bits) for each of
	      the requested states.
  @enddesc 
@@*/

SpaceMask_Type*
SpaceMask_setup_new_type(CCTK_INT8 new_bits, char* type_name,
			 int nstates, char** state_list, 
			 CCTK_INT8* state_mask)
{
  SpaceMask_Type* new_type;
  int j;

  new_type = (SpaceMask_Type*) malloc (sizeof(SpaceMask_Type));
  new_type->bitmask = new_bits;
  new_type->nstates = nstates;
  new_type->name = type_name;
  new_type->state_list =
    (SpaceMask_State**) malloc (nstates*sizeof(SpaceMask_State*));

  for (j=0; j<nstates; ++j)
    new_type->state_list[j] = SpaceMask_setup_new_state(state_mask[j],
							state_list[j]);
  return new_type;
}

/*@@
  @routine    SpaceMask_append_type_to_registry
  @author     Denis Pollney
  @date       15 October 2002
  @desc 
              Adds a new type to the spacemask_registry.
  @enddesc 
@@*/

void
SpaceMask_append_type_to_registry(SpaceMask_Type* new_type)
{
  SpaceMask_Type** new_type_list;
  int ntypes;
  int i;

  if (spacemask_registry == NULL)
    {
      spacemask_registry =
	(SpaceMask_Registry*) malloc (sizeof(SpaceMask_Registry));
      ntypes = 1;
      new_type_list = (SpaceMask_Type**) malloc (sizeof(SpaceMask_Type*));
      new_type_list[0] = new_type;
    }
  else
    {
      ntypes = spacemask_registry->ntypes + 1;
      new_type_list = 
	(SpaceMask_Type**) malloc (ntypes*sizeof(SpaceMask_Type*));
      for (i=0; i<ntypes-1; ++i)
	new_type_list[i] = spacemask_registry->type_list[i];
      new_type_list[ntypes-1] = new_type;
      free(spacemask_registry->type_list);
    }

  spacemask_registry->ntypes = ntypes;
  spacemask_registry->type_list = new_type_list;
}

/*@@
  @routine    SpaceMask_RegisterType
  @author     Denis Pollney
  @date       15 October 2002
  @desc 
              Allocates a set of bits of the SpaceMask to represent
	      a set of states of the named type.
  @enddesc 
@@*/

int
SpaceMask_RegisterType(char* type_name, int nstates, char** state_list)
{
  SpaceMask_Type* new_type;
  CCTK_INT8 new_bits;
  CCTK_INT8* state_mask;
  int bit_nbr;

  bit_nbr = SpaceMask_get_bit_nbr(nstates);
  new_bits = SpaceMask_get_free_bits(bit_nbr);
  state_mask = SpaceMask_determine_state_mask(new_bits, nstates);

  new_type = SpaceMask_setup_new_type(new_bits, type_name, nstates, 
				      state_list, state_mask);

  SpaceMask_append_type_to_registry (new_type);

  return 0;
}

/*@@
  @routine    SpaceMask_AppendStatesToType
  @author     Denis Pollney
  @date       15 October 2002
  @desc 
              Adds a new set of possible states to an already existing
	      type. If required, new bits of the mask are allocated to the
	      given state. If bits are not available for this, then an
	      error is returned.
  @enddesc 
@@*/

int
SpaceMask_AppendStatesToType(char* type_name, int nstates, char** state_list)
{
  CCTK_INT8 new_bits;
  CCTK_INT8 allocated_bits;
  CCTK_INT8* state_mask;
  SpaceMask_Type* old_type;
  SpaceMask_Type* new_type;
  char** new_state_list;
  int i;
  int j;
  int old_type_idx;
  int new_bit_nbr;
  int total_nstates;
  
  old_type = NULL;
  for (i=0; i<spacemask_registry->ntypes; ++i)
    {
      if (!strcmp(spacemask_registry->type_list[i]->name, type_name))
	{
	  old_type = spacemask_registry->type_list[i];
	  old_type_idx = i;
	}
    }

  if (old_type == NULL)
    {
      CCTK_VWarn(0, __LINE__, __FILE__, CCTK_THORNSTRING,
		 "Mask type \"%s\" has not been registered", type_name);
      return -1;
    }

  total_nstates = old_type->nstates + nstates;
  new_bit_nbr = SpaceMask_get_bit_nbr(total_nstates) - 
    SpaceMask_get_bit_nbr(old_type->nstates);

  new_bits = SpaceMask_get_free_bits(new_bit_nbr);
  allocated_bits = old_type->bitmask | new_bits;

  state_mask = SpaceMask_determine_state_mask(allocated_bits, total_nstates);

  new_state_list = (char**) malloc (total_nstates*sizeof(char*));

  i = 0;
  for (j=0; j<old_type->nstates; ++j, ++i)
    new_state_list[i] = old_type->state_list[j]->name;
  for (j=0; j<nstates; ++j, ++i)
    new_state_list[i] = state_list[j];

  new_type = SpaceMask_setup_new_type(allocated_bits, type_name, total_nstates,
				      new_state_list, state_mask);
  free(old_type);

  spacemask_registry->type_list[old_type_idx] = new_type;

  return 0;
}

/*@@
  @routine    SpaceMask_GetTypeBits
  @author     Denis Pollney
  @date       15 October 2002
  @desc 
              Returns the bitmask corresponding to the given type. Bits
	      which are allocated to the given type are set to 1, all other
	      bits are 0.
  @enddesc 
@@*/

CCTK_INT8
SpaceMask_GetTypeBits(char* type_name)
{
  int i;

  for (i=0; i<spacemask_registry->ntypes; ++i)
    {
      if (!strcmp(spacemask_registry->type_list[i]->name, type_name))
	return spacemask_registry->type_list[i]->bitmask;
    }

  CCTK_VInfo (CCTK_THORNSTRING, "Type \"%s\" has not been registered.\n",
	      type_name);

  return 0;
}

/*@@
  @routine    SpaceMask_GetStateBits
  @author     Denis Pollney
  @date       15 October 2002
  @desc 
              Returns the bitmask corresponding to the given state.
  @enddesc 
@@*/

CCTK_INT8
SpaceMask_GetStateBits(char* type_name, char* state_name)
{
  SpaceMask_Type* type;
  int i, j;

  for (i=0; i<spacemask_registry->ntypes; ++i)
    {
      if (!strcmp(spacemask_registry->type_list[i]->name, type_name))
	{
	  type = spacemask_registry->type_list[i];
	  for (j=0; j<type->nstates; ++j)
	    {
	      if (!strcmp(type->state_list[j]->name, state_name))
		return type->state_list[j]->bitmask;
	    }
	}
    }

  CCTK_VInfo (CCTK_THORNSTRING, 
	      "Requested state \"%s\" could not be found in type \"%s\"\n",
	      state_name, type_name);

  return 0;
}

/*@@
  @routine    SpaceMask_SetState
  @author     Denis Pollney
  @date       15 October 2002
  @desc 
              Sets the mask at a point to the given state.
  @enddesc 
@@*/

void
SpaceMask_SetState(CCTK_INT8* mask, int point, char* type_name, char* state)
{
  CCTK_INT8 type_bits;
  CCTK_INT8 state_bits;

  type_bits = SpaceMask_GetTypeBits(type_name);
  state_bits = SpaceMask_GetStateBits(type_name, state);

  SpaceMask_SetStateBits(mask, point, type_bits, state_bits);
}

/*@@
  @routine    SpaceMask_CheckState
  @author     Denis Pollney
  @date       15 October 2002
  @desc 
              Checks that the mask at a point has the given state, in which
	      case return 1, otherwise return 0.
  @enddesc 
@@*/

int
SpaceMask_CheckState(CCTK_INT8* mask, int point, char* type_name, char* state)
{
  CCTK_INT8 type_bits;
  CCTK_INT8 state_bits;

  type_bits = SpaceMask_GetTypeBits(type_name);
  state_bits = SpaceMask_GetStateBits(type_name, state);

  return SpaceMask_CheckStateBits(mask, point, type_bits, state_bits);
}


/********************************************************************
 *********************  Fortran Wrappers  ***************************
 ********************************************************************/

/* How do you pass the char** state list from fortran???
void
CCTK_FCALL CCTK_FNAME(SpaceMask_RegisterType)(int* ierr, char* type_name,
					      int* nstates, char** state_list)
{
  *ierr = SpaceMask_RegisterType(type_name, *nstates, state_list);
}
*/

void
CCTK_FCALL CCTK_FNAME(SpaceMask_GetTypeBits)(CCTK_INT8* type_bits,
					     ONE_FORTSTRING_ARG)
{
  ONE_FORTSTRING_CREATE(type_name)

  *type_bits = SpaceMask_GetTypeBits(type_name);

  free(type_name);
}

void
CCTK_FCALL CCTK_FNAME(SpaceMask_GetStateBits)(CCTK_INT8* state_bits,
					      TWO_FORTSTRING_ARG)
{

  TWO_FORTSTRING_CREATE(type_name, state_name)

  *state_bits = SpaceMask_GetStateBits(type_name, state_name);
}

void
CCTK_FCALL CCTK_FNAME(SpaceMask_SetState)(CCTK_INT8* mask,
					  CCTK_INT* point, TWO_FORTSTRING_ARG)
{
  TWO_FORTSTRING_CREATE(type_name, state)

  SpaceMask_SetState(mask, *point, type_name, state);
}

void
CCTK_FCALL CCTK_FNAME(SpaceMask_CheckState)(int* retval,
					    CCTK_INT8* mask,
					    CCTK_INT* point,
					    TWO_FORTSTRING_ARG)
{
  TWO_FORTSTRING_CREATE(type_name, state)

  *retval = SpaceMask_CheckState(mask, *point, type_name, state);
}