/* Address ranges.
   Copyright (C) 1998, 2007, 2008, 2009, 2010, 2011
   Free Software Foundation, Inc.
   Contributed by Cygnus Solutions.

This file is part of the GNU Simulators.

This program 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 3 of the License, or
(at your option) any later version.

This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.  */

/* Tell sim-arange.h it's us.  */
#define SIM_ARANGE_C

#include "libiberty.h"
#include "sim-basics.h"
#include "sim-assert.h"

#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif

#ifdef HAVE_STRING_H
#include <string.h>
#endif

#define DEFINE_INLINE_P (! defined (SIM_ARANGE_C_INCLUDED))
#define DEFINE_NON_INLINE_P defined (SIM_ARANGE_C_INCLUDED)

#if DEFINE_NON_INLINE_P

/* Insert a range.  */

static void
insert_range (ADDR_SUBRANGE **pos, ADDR_SUBRANGE *asr)
{
  asr->next = *pos;
  *pos = asr;
}

/* Delete a range.  */

static void
delete_range (ADDR_SUBRANGE **thisasrp)
{
  ADDR_SUBRANGE *thisasr;

  thisasr = *thisasrp;
  *thisasrp = thisasr->next;

  free (thisasr);
}

/* Add or delete an address range.
   This code was borrowed from linux's locks.c:posix_lock_file().
   ??? Todo: Given our simpler needs this could be simplified
   (split into two fns).  */

static void
frob_range (ADDR_RANGE *ar, address_word start, address_word end, int delete_p)
{
  ADDR_SUBRANGE *asr;
  ADDR_SUBRANGE *new_asr, *new_asr2;
  ADDR_SUBRANGE *left = NULL;
  ADDR_SUBRANGE *right = NULL;
  ADDR_SUBRANGE **before;
  ADDR_SUBRANGE init_caller;
  ADDR_SUBRANGE *caller = &init_caller;
  int added_p = 0;

  memset (caller, 0, sizeof (ADDR_SUBRANGE));
  new_asr = ZALLOC (ADDR_SUBRANGE);
  new_asr2 = ZALLOC (ADDR_SUBRANGE);

  caller->start = start;
  caller->end = end;
  before = &ar->ranges;

  while ((asr = *before) != NULL)
    {
      if (! delete_p)
	{
	  /* Try next range if current range preceeds new one and not
	     adjacent or overlapping.  */
	  if (asr->end < caller->start - 1)
	    goto next_range;

	  /* Break out if new range preceeds current one and not
	     adjacent or overlapping.  */
	  if (asr->start > caller->end + 1)
	    break;

	  /* If we come here, the new and current ranges are adjacent or
	     overlapping. Make one range yielding from the lower start address
	     of both ranges to the higher end address.  */
	  if (asr->start > caller->start)
	    asr->start = caller->start;
	  else
	    caller->start = asr->start;
	  if (asr->end < caller->end)
	    asr->end = caller->end;
	  else
	    caller->end = asr->end;

	  if (added_p)
	    {
	      delete_range (before);
	      continue;
	    }
	  caller = asr;
	  added_p = 1;
	}
      else /* deleting a range */
	{
	  /* Try next range if current range preceeds new one.  */
	  if (asr->end < caller->start)
	    goto next_range;

	  /* Break out if new range preceeds current one.  */
	  if (asr->start > caller->end)
	    break;

	  added_p = 1;

	  if (asr->start < caller->start)
	    left = asr;

	  /* If the next range in the list has a higher end
	     address than the new one, insert the new one here.  */
	  if (asr->end > caller->end)
	    {
	      right = asr;
	      break;
	    }
	  if (asr->start >= caller->start)
	    {
	      /* The new range completely replaces an old
	         one (This may happen several times).  */
	      if (added_p)
		{
		  delete_range (before);
		  continue;
		}

	      /* Replace the old range with the new one.  */
	      asr->start = caller->start;
	      asr->end = caller->end;
	      caller = asr;
	      added_p = 1;
	    }
	}

      /* Go on to next range.  */
    next_range:
      before = &asr->next;
    }

  if (!added_p)
    {
      if (delete_p)
	goto out;
      new_asr->start = caller->start;
      new_asr->end = caller->end;
      insert_range (before, new_asr);
      new_asr = NULL;
    }
  if (right)
    {
      if (left == right)
	{
	  /* The new range breaks the old one in two pieces,
	     so we have to use the second new range.  */
	  new_asr2->start = right->start;
	  new_asr2->end = right->end;
	  left = new_asr2;
	  insert_range (before, left);
	  new_asr2 = NULL;
	}
      right->start = caller->end + 1;
    }
  if (left)
    {
      left->end = caller->start - 1;
    }

 out:
  if (new_asr)
    free (new_asr);
  if (new_asr2)
    free (new_asr2);
}

/* Free T and all subtrees.  */

static void
free_search_tree (ADDR_RANGE_TREE *t)
{
  if (t != NULL)
    {
      free_search_tree (t->lower);
      free_search_tree (t->higher);
      free (t);
    }
}

/* Subroutine of build_search_tree to recursively build a balanced tree.
   ??? It's not an optimum tree though.  */

static ADDR_RANGE_TREE *
build_tree_1 (ADDR_SUBRANGE **asrtab, unsigned int n)
{
  unsigned int mid = n / 2;
  ADDR_RANGE_TREE *t;

  if (n == 0)
    return NULL;
  t = (ADDR_RANGE_TREE *) xmalloc (sizeof (ADDR_RANGE_TREE));
  t->start = asrtab[mid]->start;
  t->end = asrtab[mid]->end;
  if (mid != 0)
    t->lower = build_tree_1 (asrtab, mid);
  else
    t->lower = NULL;
  if (n > mid + 1)
    t->higher = build_tree_1 (asrtab + mid + 1, n - mid - 1);
  else
    t->higher = NULL;
  return t;
}

/* Build a search tree for address range AR.  */

static void
build_search_tree (ADDR_RANGE *ar)
{
  /* ??? Simple version for now.  */
  ADDR_SUBRANGE *asr,**asrtab;
  unsigned int i, n;

  for (n = 0, asr = ar->ranges; asr != NULL; ++n, asr = asr->next)
    continue;
  asrtab = (ADDR_SUBRANGE **) xmalloc (n * sizeof (ADDR_SUBRANGE *));
  for (i = 0, asr = ar->ranges; i < n; ++i, asr = asr->next)
    asrtab[i] = asr;
  ar->range_tree = build_tree_1 (asrtab, n);
  free (asrtab);
}

void
sim_addr_range_add (ADDR_RANGE *ar, address_word start, address_word end)
{
  frob_range (ar, start, end, 0);

  /* Rebuild the search tree.  */
  /* ??? Instead of rebuilding it here it could be done in a module resume
     handler, say by first checking for a `changed' flag, assuming of course
     this would never be done while the simulation is running.  */
  free_search_tree (ar->range_tree);
  build_search_tree (ar);
}

void
sim_addr_range_delete (ADDR_RANGE *ar, address_word start, address_word end)
{
  frob_range (ar, start, end, 1);

  /* Rebuild the search tree.  */
  /* ??? Instead of rebuilding it here it could be done in a module resume
     handler, say by first checking for a `changed' flag, assuming of course
     this would never be done while the simulation is running.  */
  free_search_tree (ar->range_tree);
  build_search_tree (ar);
}

#endif /* DEFINE_NON_INLINE_P */

#if DEFINE_INLINE_P

SIM_ARANGE_INLINE int
sim_addr_range_hit_p (ADDR_RANGE *ar, address_word addr)
{
  ADDR_RANGE_TREE *t = ar->range_tree;

  while (t != NULL)
    {
      if (addr < t->start)
	t = t->lower;
      else if (addr > t->end)
	t = t->higher;
      else
	return 1;
    }
  return 0;
}

#endif /* DEFINE_INLINE_P */