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/* Address ranges.

   Copyright (C) 1998, 2007, 2008, 2009, 2010 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 */