gconv_db.c

KPIT GNU Tools is a set of GNU development tools for Renesas microcontrollers.

     or `fromset_expand', ending at that node.  best_cost_lo and
     best_cost_hi represent the minimum over the elements of the
     `solution' list.  */

  if (fromset_expand != NULL)
    {
      first = NEW_STEP (fromset_expand, 0, 0, NULL, NULL);
      first->next = NEW_STEP (fromset, 0, 0, NULL, NULL);
      lastp = &first->next->next;
    }
  else
    {
      first = NEW_STEP (fromset, 0, 0, NULL, NULL);
      lastp = &first->next;
    }

  for (current = first; current != NULL; current = current->next)
    {
      /* Now match all the available module specifications against the
         current charset name.  If any of them matches check whether
         we already have a derivation for this charset.  If yes, use the
         one with the lower costs.  Otherwise add the new charset at the
         end.

	 The module database is organized in a tree form which allows
	 searching for prefixes.  So we search for the first entry with a
	 matching prefix and any other matching entry can be found from
	 this place.  */
      struct gconv_module *node;

      /* Maybe it is not necessary anymore to look for a solution for
	 this entry since the cost is already as high (or higher) as
	 the cost for the best solution so far.  */
      if (current->cost_hi > best_cost_hi
	  || (current->cost_hi == best_cost_hi
	      && current->cost_lo >= best_cost_lo))
	continue;

      node = __gconv_modules_db;
      while (node != NULL)
	{
	  int cmpres = strcmp (current->result_set, node->from_string);
	  if (cmpres == 0)
	    {
	      /* Walk through the list of modules with this prefix and
		 try to match the name.  */
	      struct gconv_module *runp;

	      /* Check all the modules with this prefix.  */
	      runp = node;
	      do
		{
		  const char *result_set = (strcmp (runp->to_string, "-") == 0
					    ? (toset_expand ?: toset)
					    : runp->to_string);
		  int cost_hi = runp->cost_hi + current->cost_hi;
		  int cost_lo = runp->cost_lo + current->cost_lo;
		  struct derivation_step *step;

		  /* We managed to find a derivation.  First see whether
		     we have reached one of the goal nodes.  */
		  if (strcmp (result_set, toset) == 0
		      || (toset_expand != NULL
			  && strcmp (result_set, toset_expand) == 0))
		    {
		      /* Append to the `solution' list if there
			 is no entry with this name.  */
		      for (step = solution; step != NULL; step = step->next)
			if (strcmp (result_set, step->result_set) == 0)
			  break;

		      if (step == NULL)
			{
			  step = NEW_STEP (result_set,
					   cost_hi, cost_lo,
					   runp, current);
			  step->next = solution;
			  solution = step;
			}
		      else if (step->cost_hi > cost_hi
			       || (step->cost_hi == cost_hi
				   && step->cost_lo > cost_lo))
			{
			  /* A better path was found for the node,
			     on the `solution' list.  */
			  step->code = runp;
			  step->last = current;
			  step->cost_hi = cost_hi;
			  step->cost_lo = cost_lo;
			}

		      /* Update best_cost accordingly.  */
		      if (cost_hi < best_cost_hi
			  || (cost_hi == best_cost_hi
			      && cost_lo < best_cost_lo))
			{
			  best_cost_hi = cost_hi;
			  best_cost_lo = cost_lo;
			}
		    }
		  else if (cost_hi < best_cost_hi
			   || (cost_hi == best_cost_hi
			       && cost_lo < best_cost_lo))
		    {
		      /* Append at the end of the `first' list if there
			 is no entry with this name.  */
		      for (step = first; step != NULL; step = step->next)
			if (strcmp (result_set, step->result_set) == 0)
			  break;

		      if (step == NULL)
			{
			  *lastp = NEW_STEP (result_set,
					     cost_hi, cost_lo,
					     runp, current);
			  lastp = &(*lastp)->next;
			}
		      else if (step->cost_hi > cost_hi
			       || (step->cost_hi == cost_hi
				   && step->cost_lo > cost_lo))
			{
			  /* A better path was found for the node,
			     on the `first' list.  */
			  step->code = runp;
			  step->last = current;

			  /* Update the cost for all steps.  */
			  for (step = first; step != NULL;
			       step = step->next)
			    /* But don't update the start nodes.  */
			    if (step->code != NULL)
			      {
				struct derivation_step *back;
				int hi, lo;

				hi = step->code->cost_hi;
				lo = step->code->cost_lo;

				for (back = step->last; back->code != NULL;
				     back = back->last)
				  {
				    hi += back->code->cost_hi;
				    lo += back->code->cost_lo;
				  }

				step->cost_hi = hi;
				step->cost_lo = lo;
			      }

			  /* Likewise for the nodes on the solution list.
			     Also update best_cost accordingly.  */
			  for (step = solution; step != NULL;
			       step = step->next)
			    {
			      step->cost_hi = (step->code->cost_hi
					       + step->last->cost_hi);
			      step->cost_lo = (step->code->cost_lo
					       + step->last->cost_lo);

			      if (step->cost_hi < best_cost_hi
				  || (step->cost_hi == best_cost_hi
				      && step->cost_lo < best_cost_lo))
				{
				  best_cost_hi = step->cost_hi;
				  best_cost_lo = step->cost_lo;
				}
			    }
			}
		    }

		  runp = runp->same;
		}
	      while (runp != NULL);

	      break;
	    }
	  else if (cmpres < 0)
	    node = node->left;
	  else
	    node = node->right;
	}
    }

  if (solution != NULL)
    {
      /* We really found a way to do the transformation.  */

      /* Choose the best solution.  This is easy because we know that
	 the solution list has at most length 2 (one for every possible
	 goal node).  */
      if (solution->next != NULL)
	{
	  struct derivation_step *solution2 = solution->next;

	  if (solution2->cost_hi < solution->cost_hi
	      || (solution2->cost_hi == solution->cost_hi
		  && solution2->cost_lo < solution->cost_lo))
	    solution = solution2;
	}

      /* Now build a data structure describing the transformation steps.  */
      result = gen_steps (solution, toset_expand ?: toset,
			  fromset_expand ?: fromset, handle, nsteps);
    }
  else
    {
      /* We haven't found a transformation.  Clear the result values.  */
      *handle = NULL;
      *nsteps = 0;
    }

  /* Add result in any case to list of known derivations.  */
  add_derivation (fromset_expand ?: fromset, toset_expand ?: toset,
		  *handle, *nsteps);

  return result;
}


/* Control of initialization.  */
__libc_once_define (static, once);


static const char *
do_lookup_alias (const char *name)
{
  struct gconv_alias key;
  struct gconv_alias **found;

  key.fromname = (char *) name;
  found = tfind (&key, &__gconv_alias_db, __gconv_alias_compare);
  return found != NULL ? (*found)->toname : NULL;
}


int
internal_function
__gconv_compare_alias (const char *name1, const char *name2)
{
  int result;

  /* Ensure that the configuration data is read.  */
  __libc_once (once, __gconv_read_conf);

  if (__gconv_compare_alias_cache (name1, name2, &result) != 0)
    result = strcmp (do_lookup_alias (name1) ?: name1,
		     do_lookup_alias (name2) ?: name2);

  return result;
}


int
internal_function
__gconv_find_transform (const char *toset, const char *fromset,
			struct __gconv_step **handle, size_t *nsteps,
			int flags)
{
  const char *fromset_expand;
  const char *toset_expand;
  int result;

  /* Ensure that the configuration data is read.  */
  __libc_once (once, __gconv_read_conf);

  /* Acquire the lock.  */
#ifdef HAVE_DD_LOCK
  __lock_acquire(lock);
#endif

  result = __gconv_lookup_cache (toset, fromset, handle, nsteps, flags);
  if (result != __GCONV_NODB)
    {
      /* We have a cache and could resolve the request, successful or not.  */
#ifdef HAVE_DD_LOCK
      __lock_release(lock);
#endif

      return result;
    }

  /* If we don't have a module database return with an error.  */
  if (__gconv_modules_db == NULL)
    {
#ifdef HAVE_DD_LOCK
  __lock_release(lock);
#endif

      return __GCONV_NOCONV;
    }

  /* See whether the names are aliases.  */
  fromset_expand = do_lookup_alias (fromset);
  toset_expand = do_lookup_alias (toset);

  if (__builtin_expect (flags & GCONV_AVOID_NOCONV, 0)
      /* We are not supposed to create a pseudo transformation (means
	 copying) when the input and output character set are the same.  */
      && (strcmp (toset, fromset) == 0
	  || (toset_expand != NULL && strcmp (toset_expand, fromset) == 0)
	  || (fromset_expand != NULL
	      && (strcmp (toset, fromset_expand) == 0
		  || (toset_expand != NULL
		      && strcmp (toset_expand, fromset_expand) == 0)))))
    {
      /* Both character sets are the same.  */
#ifdef HAVE_DD_LOCK
  __lock_release(lock);
#endif

      return __GCONV_NOCONV;
    }

  result = find_derivation (toset, toset_expand, fromset, fromset_expand,
			    handle, nsteps);

  /* Release the lock.  */
#ifdef HAVE_DD_LOCK
  __lock_release(lock);
#endif


  /* The following code is necessary since `find_derivation' will return
     GCONV_OK even when no derivation was found but the same request
     was processed before.  I.e., negative results will also be cached.  */
  return (result == __GCONV_OK
	  ? (*handle == NULL ? __GCONV_NOCONV : __GCONV_OK)
	  : result);
}


/* Release the entries of the modules list.  */
int
internal_function
__gconv_close_transform (struct __gconv_step *steps, size_t nsteps)
{
  int result = __GCONV_OK;
  size_t cnt;

  /* Acquire the lock.  */
#ifdef HAVE_DD_LOCK
  __lock_acquire(lock);
#endif


#ifndef STATIC_GCONV
  cnt = nsteps;
  while (cnt-- > 0)
    __gconv_release_step (&steps[cnt]);
#endif

  /* If we use the cache we free a bit more since we don't keep any
     transformation records around, they are cheap enough to
     recreate.  */
  __gconv_release_cache (steps, nsteps);

  /* Release the lock.  */
#ifdef HAVE_DD_LOCK
  __lock_release(lock);
#endif


  return result;
}


/* Free the modules mentioned.  */
static void
internal_function
free_modules_db (struct gconv_module *node)
{
  if (node->left != NULL)
    free_modules_db (node->left);
  if (node->right != NULL)
    free_modules_db (node->right);
  do
    {
      struct gconv_module *act = node;
      node = node->same;
      if (act->module_name[0] == '/')
	free (act);
    }
  while (node != NULL);
}


/* Free all resources if necessary.  */
static void __attribute__ ((unused))
free_mem (void)
{
  if (__gconv_alias_db != NULL)
    tdestroy (__gconv_alias_db, free);

  if (__gconv_modules_db != NULL)
    free_modules_db (__gconv_modules_db);

  if (known_derivations != NULL)
    tdestroy (known_derivations, free_derivation);
}

text_set_element (__libc_subfreeres, free_mem);