1 files changed, 280 insertions, 173 deletions

diff --git a/iconv/gconv_db.c b/iconv/gconv_db.c
index e6253b8..5269d79 100644
--- a/iconv/gconv_db.c
+++ b/iconv/gconv_db.c
@@ -1,5 +1,5 @@
 /* Provide access to the collection of available transformation modules.
-   Copyright (C) 1997, 1998 Free Software Foundation, Inc.
+   Copyright (C) 1997, 1998, 1999 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
 
@@ -18,9 +18,11 @@
    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
    Boston, MA 02111-1307, USA.  */
 
+#include <limits.h>
 #include <search.h>
 #include <stdlib.h>
 #include <string.h>
+#include <sys/param.h>
 #include <bits/libc-lock.h>
 
 #include <ldsodefs.h>
@@ -32,8 +34,7 @@
 void *__gconv_alias_db;
 
 /* Array with available modules.  */
-size_t __gconv_nmodules;
-struct gconv_module **__gconv_modules_db;
+struct gconv_module *__gconv_modules_db;
 
 /* We modify global data.   */
 __libc_lock_define_initialized (static, lock)
@@ -55,14 +56,20 @@ __gconv_alias_compare (const void *p1, const void *p2)
 struct derivation_step
 {
   const char *result_set;
+  size_t result_set_len;
+  int cost_lo;
+  int cost_hi;
   struct gconv_module *code;
   struct derivation_step *last;
   struct derivation_step *next;
 };
 
-#define NEW_STEP(result, module, last_mod) \
+#define NEW_STEP(result, hi, lo, module, last_mod) \
   ({ struct derivation_step *newp = alloca (sizeof (struct derivation_step)); \
      newp->result_set = result;						      \
+     newp->result_set_len = strlen (result);				      \
+     newp->cost_hi = hi;						      \
+     newp->cost_lo = lo;						      \
      newp->code = module;						      \
      newp->last = last_mod;						      \
      newp->next = NULL;							      \
@@ -224,7 +231,7 @@ gen_steps (struct derivation_step *best, const char *toset,
 	     {
 	       status = _CALL_DL_FCT (result[step_cnt].init_fct,
 				      (&result[step_cnt]));
-	       
+
 	       if (status != GCONV_OK)
 		 {
 		   failed = 1;
@@ -276,9 +283,9 @@ find_derivation (const char *toset, const char *toset_expand,
 		 struct gconv_step **handle, size_t *nsteps)
 {
   __libc_lock_define_initialized (static, lock)
-  struct derivation_step *first, *current, **lastp, *best = NULL;
-  int best_cost_hi = 0;
-  int best_cost_lo = 0;
+  struct derivation_step *first, *current, **lastp, *solution = NULL;
+  int best_cost_hi = INT_MAX;
+  int best_cost_lo = INT_MAX;
   int result;
 
   result = derivation_lookup (fromset_expand ?: fromset, toset_expand ?: toset,
@@ -299,202 +306,287 @@ find_derivation (const char *toset, const char *toset_expand,
       return result;
     }
 
-  /* ### TODO
-     For now we use a simple algorithm with quadratic runtime behaviour.
+  /* For now we use a simple algorithm with quadratic runtime behaviour.
      The task is to match the `toset' with any of the available rules,
      starting from FROMSET.  */
   if (fromset_expand != NULL)
     {
-      first = NEW_STEP (fromset_expand, NULL, NULL);
-      first->next = NEW_STEP (fromset, NULL, 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, NULL, NULL);
+      first = NEW_STEP (fromset, 0, 0, NULL, NULL);
       lastp = &first->next;
     }
 
-  current = first;
-  while (current != NULL)
+  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.  */
-      size_t cnt;
-
-      for (cnt = 0; cnt < __gconv_nmodules; ++cnt)
-        {
-	  const char *result_set = NULL;
+         end.
+
+	 The module database is organized in a tree form which allows to
+	 search 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 = __gconv_modules_db;
+
+      /* Maybe it is not necessary anymore to look for a solution for
+	 this entry since the cost is already as high (or heigher) 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;
+
+      while (node != NULL)
+	{
+	  int cmpres = strncmp (current->result_set, node->from_constpfx,
+				MIN (current->result_set_len,
+				     node->from_constpfx_len));
 
-	  if (__gconv_modules_db[cnt]->from_pattern == NULL)
+	  if (cmpres == 0)
 	    {
-	      if (__strcasecmp (current->result_set,
-				__gconv_modules_db[cnt]->from_constpfx) == 0)
+	      /* Walk through the list of modules with this prefix and
+		 try to match the name.  */
+	      struct gconv_module *runp;
+
+	      if (current->result_set_len < node->from_constpfx_len)
+		/* Cannot possibly match.  */
+		break;
+
+	      /* Check all the modules with this prefix.  */
+	      runp = node;
+	      do
 		{
-		  if (strcmp (__gconv_modules_db[cnt]->to_string, "-") == 0)
-		    result_set = toset_expand ?: toset;
+		  const char *result_set = NULL;
+
+		  if (runp->from_pattern == NULL)
+		    {
+		      /* This is a simple entry and therefore we have a
+			 found an matching entry if the strings are really
+			 equal.  */
+		      if (current->result_set_len == runp->from_constpfx_len)
+			{
+			  if (strcmp (runp->to_string, "-") == 0)
+			    result_set = toset_expand ?: toset;
+			  else
+			    result_set = runp->to_string;
+			}
+		    }
 		  else
-		    result_set = __gconv_modules_db[cnt]->to_string;
-		}
-	    }
-	  else
-	    /* We have a regular expression.  First see if the prefix
-	       matches.  */
-	    if (__strncasecmp (current->result_set,
-			       __gconv_modules_db[cnt]->from_constpfx,
-			       __gconv_modules_db[cnt]->from_constpfx_len)
-		== 0)
-	      {
-		/* First compile the regex if not already done.  */
-		if (__gconv_modules_db[cnt]->from_regex == NULL)
-		  {
-		    if (__regcomp (&__gconv_modules_db[cnt]->from_regex_mem,
-				   __gconv_modules_db[cnt]->from_pattern,
-				   REG_EXTENDED | REG_ICASE) != 0)
-		      /* Something is wrong.  Remember this.  */
-		      __gconv_modules_db[cnt]->from_regex = (regex_t *) -1L;
-		    else
-		      __gconv_modules_db[cnt]->from_regex
-			= &__gconv_modules_db[cnt]->from_regex_mem;
-		  }
-
-		if (__gconv_modules_db[cnt]->from_regex != (regex_t *) -1L)
-		  {
-		    /* Try to match the from name.  */
-		    regmatch_t match[4];
-
-		    if (__regexec (__gconv_modules_db[cnt]->from_regex,
-				   current->result_set, 4, match, 0) == 0
-			&& match[0].rm_so == 0
-			&& current->result_set[match[0].rm_eo] == '\0')
-		      {
-			/* At least the whole <from> string is matched.
-			   We must now match sed-like possible
-			   subexpressions from the match to the
-			   toset expression.  */
+		    {
+		      /* Compile the regular expression if necessary.  */
+		      if (runp->from_regex == NULL)
+			{
+			  if (__regcomp (&runp->from_regex_mem,
+					 runp->from_pattern,
+					 REG_EXTENDED | REG_ICASE) != 0)
+			    /* Something is wrong.  Remember this.  */
+			    runp->from_regex = (regex_t *) -1L;
+			  else
+			    runp->from_regex = &runp->from_regex_mem;
+			}
+
+		      if (runp->from_regex != (regex_t *) -1L)
+			{
+			  regmatch_t match[4];
+
+			  /* Try to match the regular expression.  */
+			  if (__regexec (runp->from_regex, current->result_set,
+					 4, match, 0) == 0
+			      && match[0].rm_so == 0
+			      && current->result_set[match[0].rm_eo] == '\0')
+			    {
+			      /* At least the whole <from> string is matched.
+				 We must now match sed-like possible
+				 subexpressions from the match to the
+				 toset expression.  */
 #define ENSURE_LEN(LEN) \
   if (wp + (LEN) >= constr + len - 1)					      \
     {									      \
       char *newp = alloca (len += 128);					      \
-      memcpy (newp, constr, wp - constr);				      \
-      wp = newp + (wp - constr);					      \
+      wp = __mempcpy (newp, constr, wp - constr);			      \
       constr = newp;							      \
     }
-			size_t len = 128;
-			char *constr = alloca (len);
-			char *wp = constr;
-			const char *cp = __gconv_modules_db[cnt]->to_string;
-
-			while (*cp != '\0')
-			  {
-			    if (*cp != '\\')
-			      {
-				ENSURE_LEN (1);
-				*wp++ = *cp++;
-			      }
-			    else if (cp[1] == '\0')
-			      /* Backslash at end of string.  */
-			      break;
-			    else
-			      {
-				++cp;
-				if (*cp == '\\')
-				  {
-				    *wp++ = *cp++;
-				    ENSURE_LEN (1);
-				  }
-				else if (*cp < '1' || *cp > '3')
-				  break;
-				else
-				  {
-				    int idx = *cp - '0';
-				    if (match[idx].rm_so == -1)
-				      /* No match.  */
-				      break;
-
-				    ENSURE_LEN (match[idx].rm_eo
-						- match[idx].rm_so);
-				    wp = __mempcpy (wp,
-						    &current->result_set[match[idx].rm_so],
-						    match[idx].rm_eo
-						    - match[idx].rm_so);
-				    ++cp;
-				  }
-			      }
-			  }
-			if (*cp == '\0' && wp != constr)
-			  {
-                                /* Terminate the constructed string.  */
-			    *wp = '\0';
-			    result_set = constr;
-			  }
-		      }
-		  }
-	      }
-
-	  if (result_set != NULL)
-	    {
-	      /* We managed to find a derivation.  First see whether
-		 this is what we are looking for.  */
-	      if (__strcasecmp (result_set, toset) == 0
-		  || (toset_expand != NULL
-		      && __strcasecmp (result_set, toset_expand) == 0))
-		{
-		  /* Determine the costs.  If they are lower than the
-		     previous solution (or this is the first solution)
-		     remember this solution.  */
-		  int cost_hi = __gconv_modules_db[cnt]->cost_hi;
-		  int cost_lo = __gconv_modules_db[cnt]->cost_lo;
-		  struct derivation_step *runp = current;
-		  while (runp->code != NULL)
-		    {
-		      cost_hi += runp->code->cost_hi;
-		      cost_lo += runp->code->cost_lo;
-		      runp = runp->last;
+			      size_t len = 128;
+			      char *constr = alloca (len);
+			      char *wp = constr;
+			      const char *cp = runp->to_string;
+
+			      while (*cp != '\0')
+				{
+				  if (*cp != '\\')
+				    {
+				      ENSURE_LEN (1);
+				      *wp++ = *cp++;
+				    }
+				  else if (cp[1] == '\0')
+				    /* Backslash at end of string.  */
+				    break;
+				  else
+				    {
+				      ++cp;
+				      if (*cp == '\\')
+					{
+					  *wp++ = *cp++;
+					  ENSURE_LEN (1);
+					}
+				      else if (*cp < '1' || *cp > '3')
+					break;
+				      else
+					{
+					  int idx = *cp - '0';
+					  if (match[idx].rm_so == -1)
+					    /* No match.  */
+					    break;
+
+					  ENSURE_LEN (match[idx].rm_eo
+						      - match[idx].rm_so);
+					  wp = __mempcpy (wp,
+							  &current->result_set[match[idx].rm_so],
+							  match[idx].rm_eo
+							  - match[idx].rm_so);
+					  ++cp;
+					}
+				    }
+				}
+			      if (*cp == '\0' && wp != constr)
+				{
+				  /* Terminate the constructed string.  */
+				  *wp = '\0';
+				  result_set = constr;
+				}
+			    }
+			}
 		    }
-		  if (best == NULL || cost_hi < best_cost_hi
-		      || (cost_hi == best_cost_hi && cost_lo < best_cost_lo))
+
+		  if (result_set != NULL)
 		    {
-		      best = NEW_STEP (result_set, __gconv_modules_db[cnt],
-				       current);
-		      best_cost_hi = cost_hi;
-		      best_cost_lo = cost_lo;
+		      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
+			 this is what we are looking for.  */
+		      if (__strcasecmp (result_set, toset) == 0
+			  || (toset_expand != NULL
+			      && __strcasecmp (result_set, toset_expand) == 0))
+			{
+			  if (solution == NULL || 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;
+			    }
+
+			  /* Append this solution to list.  */
+			  if (solution == NULL)
+			    solution = NEW_STEP (result_set, 0, 0, runp,
+						 current);
+			  else
+			    {
+			      while (solution->next != NULL)
+				solution = solution->next;
+
+			      solution->next = NEW_STEP (result_set, 0, 0,
+							 runp, current);
+			    }
+			}
+		      else if (cost_hi < best_cost_hi
+			       || (cost_hi == best_cost_hi
+				   && cost_lo < best_cost_lo))
+			{
+			  /* Append at the end if there is no entry with
+			     this name.  */
+			  for (step = first; step != NULL; step = step->next)
+			    if (__strcasecmp (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))
+			    {
+			      step->code = runp;
+			      step->last = current;
+
+			      /* Update the cost for all steps.  */
+			      for (step = first; step != NULL;
+				   step = step->next)
+				{
+				  struct derivation_step *back;
+
+				  if (step->code == NULL)
+				    /* This is one of the entries we started
+				       from.  */
+				    continue;
+
+				  step->cost_hi = step->code->cost_hi;
+				  step->cost_lo = step->code->cost_lo;
+
+				  for (back = step->last; back->code != NULL;
+				       back = back->last)
+				    {
+				      step->cost_hi += back->code->cost_hi;
+				      step->cost_lo += back->code->cost_lo;
+				    }
+				}
+
+			      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))
+				    {
+				      solution = step;
+				      best_cost_hi = step->cost_hi;
+				      best_cost_lo = step->cost_lo;
+				    }
+				}
+			    }
+			}
 		    }
+
+		  runp = runp->same;
 		}
-	      else
-		{
-		  /* Append at the end if there is no entry with this name.  */
-		  struct derivation_step *runp = first;
+	      while (runp != NULL);
 
-		  while (runp != NULL)
-		    {
-		      if (__strcasecmp (result_set, runp->result_set) == 0)
-			break;
-		      runp = runp->next;
-		    }
+	      if (current->result_set_len == node->from_constpfx_len)
+		break;
 
-		  if (runp == NULL)
-		    {
-		      *lastp = NEW_STEP (result_set, __gconv_modules_db[cnt],
-					 current);
-		      lastp = &(*lastp)->next;
-		    }
-                }
+	      node = node->matching;
 	    }
+	  else if (cmpres < 0)
+	    node = node->left;
+	  else
+	    node = node->right;
 	}
-
-      /* Go on with the next entry.  */
-      current = current->next;
     }
 
-  if (best != NULL)
+  if (solution != NULL)
     /* We really found a way to do the transformation.  Now build a data
        structure describing the transformation steps.*/
-    result = gen_steps (best, toset_expand ?: toset, fromset_expand ?: fromset,
-			handle, nsteps);
+    result = gen_steps (solution, toset_expand ?: toset,
+			fromset_expand ?: fromset, handle, nsteps);
   else
     {
       /* We haven't found a transformation.  Clear the result values.  */
@@ -620,20 +712,35 @@ __gconv_close_transform (struct gconv_step *steps, size_t nsteps)
 }
 
 
+/* 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);
+  if (node->same != NULL)
+    free_modules_db (node->same);
+  do
+    {
+      struct gconv_module *act = node;
+      node = node->matching;
+      free (act);
+    }
+  while (node != NULL);
+}
+
+
 /* Free all resources if necessary.  */
 static void __attribute__ ((unused))
 free_mem (void)
 {
-  size_t cnt;
-
   if (__gconv_alias_db != NULL)
     __tdestroy (__gconv_alias_db, free);
 
-  for (cnt = 0; cnt < __gconv_nmodules; ++cnt)
-    /* Modules which names do not start with a slash are builtin
-       transformations and the memory is not allocated dynamically.  */
-    if (__gconv_modules_db[cnt]->module_name[0] == '/')
-      free (__gconv_modules_db[cnt]);
+  free_modules_db (__gconv_modules_db);
 
   if (known_derivations != NULL)
     __tdestroy (known_derivations, free_derivation);