(print_anchor, print_glyph_positioning): New functions.
[m17n/libotf.git] / src / otfdrive.c
index 7e3ce4b..0b2ef60 100644 (file)
@@ -1,10 +1,45 @@
+/* otfdrive.c -- OpenType font driver.
+
+Copyright (C) 2003, 2004
+  National Institute of Advanced Industrial Science and Technology (AIST)
+  Registration Number H15PRO167
+
+This file is part of libotf.
+
+Libotf is free software; you can redistribute it and/or modify it
+under the terms of the GNU Lesser General Public License as published
+by the Free Software Foundation; either version 2.1 of the License, or
+(at your option) any later version.
+
+Libotf 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 Lesser General Public
+License for more details.
+
+You should have received a copy of the GNU Lesser General Public
+License along with this library, in a file named COPYING; if not,
+write to the Free Software Foundation, Inc., 59 Temple Place, Suite
+330, Boston, MA 02111-1307, USA.  */
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <config.h>
 
 #include "otf.h"
 #include "otferror.h"
 
+extern int debug_flag;
+
+/* Return nonzero (-1 if ID is zero, 1 otherwise) if OTF_Glyph *G
+   should be ignored according to LookupFlag FLAG.  */
+#define IGNORED_GLYPH(g, flag)                         \
+  ((g)->glyph_id == 0 ? -1                             \
+   : (((flag) & (1 << (g)->GlyphClass))                        \
+      || (((flag) & OTF_MarkAttachmentType)            \
+         && (g)->GlyphClass == OTF_GlyphClassMark      \
+         && ((flag) >> 8) != (g)->MarkAttachClass)))
+
 #define GSTRING_DELETE(gstring, from, len)                             \
   do {                                                                 \
     memmove (gstring->glyphs + from, gstring->glyphs + from + len,     \
@@ -20,8 +55,9 @@
        char *errfmt = "GSTRING%s";                                     \
                                                                        \
        gstring->size = gstring->used + len;                            \
-       gstring->glyphs = (OTF_Glyph *) realloc (gstring->glyphs,       \
-                                                gstring->size);        \
+       gstring->glyphs                                                 \
+         = (OTF_Glyph *) realloc (gstring->glyphs,                     \
+                                  sizeof (OTF_Glyph) * gstring->size); \
        if (! gstring->glyphs)                                          \
          OTF_ERROR (OTF_ERROR_MEMORY, "");                             \
       }                                                                        \
   } while (0)
 
 
+static unsigned get_class_def (OTF_ClassDef *, OTF_GlyphID);
+
 static int
-gstring_subst (OTF_GlyphString *gstring, int from, int to,
+gstring_subst (OTF *otf, OTF_GlyphString *gstring, int from, int to, int flag,
               OTF_GlyphID *ids, int num)
 {
   int errret = -1;
   int len = to - from;
   int i;
+  int from_idx = gstring->glyphs[from].f.index.from;
+  int to_idx = gstring->glyphs[to - 1].f.index.to;
+  int non_ignored_idx;
+
+  for (i = non_ignored_idx = to - 1; i >= from; i--)
+    {
+      OTF_Glyph *g = gstring->glyphs + i;
+
+      if (IGNORED_GLYPH (g, flag) == 1)
+       {
+         /* Move this glyph to the next of the current target of
+            substitution.  */
+         OTF_Glyph temp = *g;
+
+         memmove (g, g + 1, sizeof (OTF_Glyph) * (non_ignored_idx - i));
+         temp.f.index.from = from_idx;
+         temp.f.index.to = to_idx;
+         gstring->glyphs[non_ignored_idx--] = temp;
+         len--;
+       }
+    }
 
   if (len < num)
     GSTRING_INSERT (gstring, from, (num - len));
   else if (len > num)
     GSTRING_DELETE (gstring, from, (len - num));
   for (i = 0; i < num; i++)
-    gstring->glyphs[from + i].glyph_id = ids[i];
+    {
+      if (gstring->glyphs[from + i].glyph_id != ids[i])
+       {
+         gstring->glyphs[from + i].c = 0;
+         if (otf->gdef)
+           gstring->glyphs[from + i].GlyphClass
+             = get_class_def (&otf->gdef->glyph_class_def, ids[i]);
+         else
+           gstring->glyphs[from + i].GlyphClass = 0;
+       }
+      gstring->glyphs[from + i].glyph_id = ids[i];
+      gstring->glyphs[from + i].positioning_type = 0;
+      gstring->glyphs[from + i].f.index.from = from_idx;
+      gstring->glyphs[from + i].f.index.to = to_idx;
+    }
   return 0;
 }
 
@@ -94,98 +167,298 @@ get_class_def (OTF_ClassDef *class_def, OTF_GlyphID glyph_id)
 }
 
 static OTF_LangSys *
-get_langsys (OTF_ScriptList *script_list, char *script, char *language)
+get_langsys (OTF_ScriptList *script_list,
+            const char *script, const char *language)
 {
 
   OTF_Tag script_tag = OTF_tag (script);
   OTF_Tag langsys_tag = OTF_tag (language);
   int i, j;
+  OTF_Tag dflt_tag = OTF_tag ("DFLT");
+  OTF_Script *dflt = NULL;
 
   for (i = 0; i < script_list->ScriptCount; i++)
-    if (script_list->Script[i].ScriptTag == script_tag)
-      {
-       OTF_Script *script = script_list->Script + i;
-
-       if (! langsys_tag)
-         return &script->DefaultLangSys;
-       for (j = 0; j < script->LangSysCount; j++)
-         if (script->LangSysRecord[j].LangSysTag == langsys_tag)
-           return script->LangSys + j;
-       return &script->DefaultLangSys; 
-      }
+    {
+      OTF_Script *script = script_list->Script + i;
+
+      if (script_list->Script[i].ScriptTag == dflt_tag)
+       dflt = script;
+      if (script_list->Script[i].ScriptTag == script_tag)
+       {
+         if (! langsys_tag)
+           return &script->DefaultLangSys;
+         for (j = 0; j < script->LangSysCount; j++)
+           if (script->LangSysRecord[j].LangSysTag == langsys_tag)
+             return script->LangSys + j;
+         return &script->DefaultLangSys;       
+       }
+    }
 
-  return NULL;
+  if (! dflt)
+    dflt = script_list->Script;
+  if (! langsys_tag)
+    return &dflt->DefaultLangSys;
+  for (j = 0; j < dflt->LangSysCount; j++)
+    if (dflt->LangSysRecord[j].LangSysTag == langsys_tag)
+      return dflt->LangSys + j;
+  return &dflt->DefaultLangSys;        
 }
 
 static int
-get_feature_index (OTF_LangSys *LangSys, OTF_FeatureList *FeatureList,
-                  char *features, int *feature_index)
+setup_lookup_flags (OTF_LookupList *LookupList, OTF_FeatureList *FeatureList,
+                   OTF_LangSys *LangSys,
+                   const char *features, char *lookup_flags)
 {
-  int nfeatures = 0;
+  int i, j, n = 0;
+  OTF_Feature *feature;
+  int *feature_table = alloca (sizeof (int) * FeatureList->FeatureCount);
+
+  if (! feature_table)
+    return -1;
+  for (i = 0; i < FeatureList->FeatureCount; i++)
+    feature_table[i] = 0;
+  memset (lookup_flags, 0, LookupList->LookupCount);
 
-  if (features)
+  while (*features)
     {
-      char *p0, *p1;
-      int len = strlen (features) + 1;
-
-      p0 = alloca (len);
-      for (p1 = p0; *p1; p1++)
-       if (*p1 == ',')
-         *p1 = '\0';
-      
-      while (len > 0)
-       {
-         int this_len = strlen (p0) + 1;
-         OTF_Tag tag = OTF_tag (p0);
+      char tagname[4];
+      OTF_Tag tag;
+      int use_it = 1;
 
-         if (tag)
+      if (*features == '*')
+       {
+         /* Consume all remaining features.  */
+         for (i = 0; i < LangSys->FeatureCount; i++) 
            {
-             int i;
+             int index = LangSys->FeatureIndex[i];
 
-             for (i = 0; i < FeatureList->FeatureCount; i++)
-               if (tag == FeatureList->Feature[i].FeatureTag)
-                 {
-                   feature_index[nfeatures++] = i;
-                   if (nfeatures == FeatureList->FeatureCount)
-                     break;
-                 }
+             if (! feature_table[index])
+               {
+                 feature = FeatureList->Feature + index;
+                 for (j = 0; j < feature->LookupCount; j++)
+                   lookup_flags[feature->LookupListIndex[j]] = 1;
+               }
+           }
+         break;
+       }
+
+      if (*features == '~')
+       use_it = -1, features++;
+      for (i = 0; *features && *features != ','; i++, features++)
+       tagname[i] = *features;
+      if (*features)
+       /* Skip ',' */
+       features++;
+      for (; i < 4; i++)
+       tagname[i] = '\0';
+      tag = OTF_tag (tagname);
+      for (i = 0; i < LangSys->FeatureCount; i++)
+       {
+         feature = FeatureList->Feature + LangSys->FeatureIndex[i];
+         if (tag == feature->FeatureTag)
+           {
+             if (feature_table[i])
+               break;
+             if (use_it > 0)
+               for (j = 0; j < feature->LookupCount; j++)
+                 lookup_flags[feature->LookupListIndex[j]] = 1;
+             feature_table[i] = use_it;
+             break;
            }
-         p0 += this_len;
-         len -= this_len;
        }
     }
-  else
+  return 0;
+}
+
+static int
+match_ids (OTF_GlyphString *gstring, int gidx, int flag,
+          int count, OTF_GlyphID *ids)
+{
+  OTF_Glyph *gbeg = gstring->glyphs + gidx;
+  OTF_Glyph *gend = gstring->glyphs + gstring->used;
+  OTF_Glyph *g;
+  int i;
+
+  for (g = gbeg, i = 0; g < gend && i < count; g++)
+    if (! IGNORED_GLYPH (g, flag) && g->glyph_id != ids[i++])
+      return -1;
+  return (i < count ? -1 : g - gbeg);
+}
+
+static int
+match_chain_ids (OTF_GlyphString *gstring, int gidx, int flag,
+                OTF_ChainRule *rule)
+{
+  int i = rule->BacktrackGlyphCount;
+
+  if (i > 0)
+    {
+      int j;
+      OTF_Glyph *g;
+
+      for (j = gidx - 1, g = gstring->glyphs + j; j >= 0; j--, g--)
+       if (! IGNORED_GLYPH (g, flag) && --i == 0)
+         break;
+      if (i > 0)
+       return -1;
+      if (match_ids (gstring, j, flag,
+                    rule->BacktrackGlyphCount, rule->Backtrack)
+         < 0)
+       return -1;
+    }
+  gidx++;
+  i = match_ids (gstring, gidx, flag,
+                rule->InputGlyphCount - 1, rule->Input);
+  if (i < 0)
+    return -1;
+  gidx += i;
+  i = match_ids (gstring, gidx, flag,
+                rule->LookaheadGlyphCount, rule->LookAhead);
+  if (i < 0)
+    return -1;
+  return 0;
+}
+
+static int
+match_classes (OTF_ClassDef *class_def, OTF_GlyphString *gstring, int gidx,
+              int flag, int count, unsigned *classes)
+{
+  OTF_Glyph *gbeg = gstring->glyphs + gidx;
+  OTF_Glyph *gend = gstring->glyphs + gstring->used;
+  OTF_Glyph *g;
+  int i;
+
+  for (g = gbeg, i = 0; g < gend && i < count; g++)
+    if (! IGNORED_GLYPH (g, flag)
+       && get_class_def (class_def, g->glyph_id) != classes[i++])
+      return -1;
+  return (i < count ? -1 : g - gbeg);
+}
+
+static int
+match_chain_classes (OTF_GlyphString *gstring, int gidx, int flag,
+                    OTF_ClassDef *BacktrackClassDef,
+                    OTF_ClassDef *InputClassDef,
+                    OTF_ClassDef *LookaheadClassDef,
+                    OTF_ChainClassRule *rule)
+{
+  int i = rule->BacktrackGlyphCount;
+
+  if (i > 0)
     {
-      for (; nfeatures < LangSys->FeatureCount; nfeatures++)
-       feature_index[nfeatures] = LangSys->FeatureIndex[nfeatures];
+      int j;
+      OTF_Glyph *g;
+
+      for (j = gidx - 1, g = gstring->glyphs + j; j >= 0; j--, g--)
+       if (! IGNORED_GLYPH (g, flag) && i-- == 0)
+         break;
+      if (i > 0)
+       return -1;
+      if (match_classes (BacktrackClassDef, gstring, j, flag,
+                        rule->BacktrackGlyphCount, rule->Backtrack) < 0);
+      return -1;
     }
+  gidx++;
+  i = match_classes (InputClassDef, gstring, gidx, flag,
+                    rule->InputGlyphCount - 1, rule->Input);
+  if (i < 0)
+    return -1;
+  gidx += i;
+  i = match_classes (LookaheadClassDef, gstring, gidx, flag,
+                    rule->LookaheadGlyphCount, rule->LookAhead);
+  if (i < 0)
+    return -1;
+  return 0;
+}
+
+
+static int
+match_coverages (OTF_GlyphString *gstring, int gidx, int flag, int count,
+                OTF_Coverage *coverages)
+{
+  OTF_Glyph *gbeg = gstring->glyphs + gidx;
+  OTF_Glyph *gend = gstring->glyphs + gstring->used;
+  OTF_Glyph *g;
+  int i;
+
+  for (g = gbeg, i = 0; g < gend && i < count; g++)
+    if (! IGNORED_GLYPH (g, flag)
+       && get_coverage_index (coverages + i++, g->glyph_id) < 0)
+      return -1;
+  return (i < count ? -1 : g - gbeg);
+}
 
-  return nfeatures;
+static int
+match_chain_coverages (OTF_GlyphString *gstring, int gidx, int flag,
+                      OTF_GSUB_ChainContext3 *context3)
+{
+  int i = context3->BacktrackGlyphCount;
+
+  if (i > 0)
+    {
+      int j;
+      OTF_Glyph *g;
+
+      for (j = gidx - 1, g= gstring->glyphs +j; j >= 0; j--, g--)
+       if (! IGNORED_GLYPH (g, flag) && --i == 0)
+         break;
+      if (i > 0)
+       return -1;
+      if (match_coverages (gstring, j, flag, context3->BacktrackGlyphCount,
+                          context3->Backtrack) < 0)
+       return -1;
+    }
+  gidx++;
+  if (context3->InputGlyphCount > 1)
+    {
+      i = match_coverages (gstring, gidx, flag, context3->InputGlyphCount - 1,
+                          context3->Input + 1);
+      if (i < 0)
+       return -1;
+      gidx += i;
+    }
+  if (match_coverages (gstring, gidx, flag, context3->LookaheadGlyphCount,
+                      context3->LookAhead) < 0)
+    return -1;
+  return 0;
 }
 
 static int
-lookup_gsub (OTF_LookupList *lookup_list, unsigned lookup_list_index,
-            OTF_GlyphString *gstring, int gidx)
+lookup_gsub (OTF *otf, OTF_LookupList *lookup_list, unsigned lookup_list_index,
+            OTF_GlyphString *gstring, int gidx, int alternate_subst)
 {
   char *errfmt = "GSUB Looking up%s";
   int errret = -1;
   OTF_Lookup *lookup = lookup_list->Lookup + lookup_list_index;
-  unsigned int flag = lookup->LookupFlag;
+  unsigned int flag = (lookup->LookupFlag
+                      & (OTF_LookupFlagIgnoreMask | OTF_MarkAttachmentType));
   int orig_gidx = gidx;
   OTF_Glyph *g = gstring->glyphs + gidx;
   int i;
 
-  if (! g->glyph_id
-      || (g->GlyphClass
-         && (flag & (1 << g->GlyphClass))))
+  if (IGNORED_GLYPH (g, flag))
     return (gidx + 1);
 
   /* Try all subtables until one of them handles the current glyph.  */
   for (i = 0; i < lookup->SubTableCount && gidx == orig_gidx; i++)
     {
+      unsigned lookup_type = lookup->LookupType;
       OTF_LookupSubTableGSUB *subtable = lookup->SubTable.gsub + i;
       int coverage_idx;
 
+      if (lookup_type == 7)
+       {
+         OTF_GSUB_Extension1 *extension1 = &subtable->u.extension1;
+
+         lookup_type = extension1->ExtensionLookupType;
+         subtable = extension1->ExtensionSubtable;
+       }
+
+      if (alternate_subst
+         ? (lookup_type != 3 && lookup_type != 5 && lookup_type != 6)
+         : (lookup_type == 3))
+       continue;
+
       if (subtable->Coverage.offset)
        {
          coverage_idx = get_coverage_index (&subtable->Coverage,
@@ -194,7 +467,7 @@ lookup_gsub (OTF_LookupList *lookup_list, unsigned lookup_list_index,
            continue;
        }
 
-      switch (lookup->LookupType)
+      switch (lookup_type)
        {
        case 1:
          if (subtable->Format == 1)
@@ -205,40 +478,51 @@ lookup_gsub (OTF_LookupList *lookup_list, unsigned lookup_list_index,
          break;
 
        case 2:
-         {
-           OTF_GSUB_Multiple1 *multiple1 = &subtable->u.multiple1;
-           OTF_Sequence *seq = multiple1->Sequence + coverage_idx;
+         if (subtable->Format == 1)
+           {
+             OTF_GSUB_Multiple1 *multiple1 = &subtable->u.multiple1;
+             OTF_Sequence *seq = multiple1->Sequence + coverage_idx;
 
-           gstring_subst (gstring, gidx, gidx + 1,
-                          seq->Substitute, seq->GlyphCount);
-           gidx += seq->GlyphCount;
-         }
+             gstring_subst (otf, gstring, gidx, gidx + 1, flag,
+                            seq->Substitute, seq->GlyphCount);
+             gidx += seq->GlyphCount;
+           }
+         else
+           OTF_ERROR (OTF_ERROR_GSUB_DRIVE, " (invalid SubFormat)");
          break;
 
        case 3:
-         OTF_ERROR (OTF_ERROR_GSUB_DRIVE, " (LookupType not yet supported)");
+         if (subtable->Format == 1)
+           {
+             OTF_GSUB_Alternate1 *alt1 = &subtable->u.alternate1;
+             OTF_AlternateSet *altset = alt1->AlternateSet + coverage_idx;
+
+             gstring_subst (otf, gstring, gidx, gidx + 1, flag,
+                            altset->Alternate, altset->GlyphCount);
+             gidx += altset->GlyphCount;;
+           }
+         else
+           OTF_ERROR (OTF_ERROR_GSUB_DRIVE, " (invalid SubFormat)");
+         break;
 
        case 4:
          if (subtable->Format == 1)
            {
              OTF_GSUB_Ligature1 *lig1 = &subtable->u.ligature1;
              OTF_LigatureSet *ligset = lig1->LigatureSet + coverage_idx;
+             OTF_Ligature *lig;
              int j;
 
              for (j = 0; j < ligset->LigatureCount; j++)
                {
-                 OTF_Ligature *lig = ligset->Ligature + j;
-                 int k;
+                 int n;
 
-                 if (gstring->used - gidx < lig->CompCount)
-                   continue;
-                 for (k = 1; k < lig->CompCount; k++)
-                   if (gstring->glyphs[gidx + k].glyph_id
-                       != lig->Component[k - 1])
-                     break;
-                 if (k < lig->CompCount)
+                 lig = ligset->Ligature + j;
+                 n = match_ids (gstring, gidx + 1, flag,
+                                lig->CompCount - 1, lig->Component);
+                 if (n < 0)
                    continue;
-                 gstring_subst (gstring, gidx, gidx + lig->CompCount,
+                 gstring_subst (otf, gstring, gidx, gidx + 1 + n, flag,
                                 &lig->LigGlyph, 1);
                  gidx++;
                  break;
@@ -247,75 +531,207 @@ lookup_gsub (OTF_LookupList *lookup_list, unsigned lookup_list_index,
          else
            OTF_ERROR (OTF_ERROR_GSUB_DRIVE, " (invalid SubFormat)");
          break;
-             
-       case 6:
+
+       case 5:
          if (subtable->Format == 1)
-           OTF_ERROR (OTF_ERROR_GSUB_DRIVE, " (not yet supported)");
+           {
+             OTF_GSUB_Context1 *context1 = &subtable->u.context1;
+             OTF_RuleSet *set = context1->RuleSet + coverage_idx;
+             OTF_Rule *rule;
+             int orig_used;
+             int j, k;
+
+             for (j = 0; j < set->RuleCount; j++)
+               {
+                 rule = set->Rule + j;
+                 if (match_ids (gstring, gidx + 1, flag,
+                                rule->GlyphCount - 1, rule->Input) < 0)
+                   continue;
+                 orig_used = gstring->used;
+                 for (k = 0; k < rule->LookupCount; k++)
+                   lookup_gsub (otf, lookup_list,
+                                rule->LookupRecord[k].LookupListIndex,
+                                gstring,
+                                gidx + rule->LookupRecord[k].SequenceIndex,
+                                alternate_subst);
+                 gidx += rule->GlyphCount + (gstring->used - orig_used);
+                 break;
+               }
+           }
          else if (subtable->Format == 2)
-           OTF_ERROR (OTF_ERROR_GSUB_DRIVE, " (not yet supported)");
-         else
            {
-             OTF_GSUB_ChainContext3 *context3
-               = &subtable->u.chain_context3;
-             int back_gidx = gidx - context3->BacktrackGlyphCount;
-             int fore_gidx = gidx + context3->InputGlyphCount;
+             OTF_GSUB_Context2 *context2 = &subtable->u.context2;
+             OTF_ClassSet *set;
+             OTF_ClassRule *rule;
+             unsigned class;
              int orig_used;
-             int j;
+             int j, k;
 
-             if (back_gidx < 0
-                 || fore_gidx + context3->LookaheadGlyphCount > gstring->used)
-               break;
+             class = get_class_def (&context2->ClassDef, g->glyph_id);
+             set = context2->ClassSet + class;
+             if (set)
+               for (j = 0; j < set->ClassRuleCnt; j++)
+                 {
+                   rule = set->ClassRule + j;
+                   if (match_classes (&context2->ClassDef,
+                                      gstring, gidx + 1, flag,
+                                      rule->GlyphCount - 1, rule->Class)
+                       < 0)
+                     continue;
+                   orig_used = gstring->used;
+                   for (k = 0; k < rule->LookupCount; k++)
+                     lookup_gsub (otf, lookup_list,
+                                  rule->LookupRecord[k].LookupListIndex,
+                                  gstring,
+                                  gidx + rule->LookupRecord[k].SequenceIndex,
+                                  alternate_subst);
+                   gidx += rule->GlyphCount + (gstring->used - orig_used);
+                   break;
+                 }
+           }
+         else                  /* subtable->Format == 3 */
+           {
+             OTF_GSUB_Context3 *context3 = &subtable->u.context3;
+             int orig_used;
+             int j;
 
-             for (j = 0; j < context3->BacktrackGlyphCount; j++)
-               if (get_coverage_index (context3->Backtrack + j,
-                                       gstring->glyphs[back_gidx + j].glyph_id)
-                   < 0)
-                 break;
-             if (j < context3->BacktrackGlyphCount)
+             if (match_coverages (gstring, gidx + 1, flag,
+                                  context3->GlyphCount - 1,
+                                  context3->Coverage + 1) < 0)
                continue;
+             orig_used = gstring->used;
+             for (j = 0; j < context3->LookupCount; j++)
+               lookup_gsub (otf, lookup_list,
+                            context3->LookupRecord[j].LookupListIndex,
+                            gstring,
+                            gidx + context3->LookupRecord[j].SequenceIndex,
+                            alternate_subst);
+             gidx += context3->GlyphCount + (gstring->used - orig_used);
+           }
+         break;
+
+       case 6:
+         if (subtable->Format == 1)
+           {
+             OTF_GSUB_ChainContext1 *context1 = &subtable->u.chain_context1;
+             OTF_ChainRuleSet *set = context1->ChainRuleSet + coverage_idx;
+             int orig_used;
+             int j, k;
+             
+             for (j = 0; j < set->ChainRuleCount; j++)
+               {
+                 OTF_ChainRule *rule = set->ChainRule + j;
 
-             /* Start from the secoding coverage_idx because the
-                first one is the same as subtable->Coverage and thus
-                already tested */
-             for (j = 1; j < context3->InputGlyphCount; j++)
-               if (get_coverage_index (context3->Input + j - 1,
-                                       gstring->glyphs[gidx + j].glyph_id)
-                   < 0)
+                 if (gidx < rule->BacktrackGlyphCount
+                     || (gidx + rule->InputGlyphCount
+                         + rule->LookaheadGlyphCount) > gstring->used)
+                   continue;
+                 if (match_chain_ids (gstring, gidx, flag, rule) < 0)
+                   continue;
+                 orig_used = gstring->used;
+                 for (k = 0; k < rule->LookupCount; k++)
+                   lookup_gsub (otf, lookup_list,
+                                rule->LookupRecord[k].LookupListIndex,
+                                gstring,
+                                gidx + rule->LookupRecord[k].SequenceIndex,
+                                alternate_subst);
+                 gidx += rule->InputGlyphCount + (gstring->used - orig_used);
                  break;
-             if (j < context3->InputGlyphCount)
-               continue;
+               }
+           }
+         else if (subtable->Format == 2)
+           {
+             OTF_GSUB_ChainContext2 *context2 = &subtable->u.chain_context2;
+             OTF_ChainClassSet *set;
+             unsigned class;
+             int j;
+             int orig_used;
+
+             class = get_class_def (&context2->InputClassDef, g->glyph_id);
+             set = context2->ChainClassSet + class;
+             for (j = 0; j < set->ChainClassRuleCnt; j++)
+               {
+                 OTF_ChainClassRule *rule = set->ChainClassRule + j;
+                 int k;
 
-             for (j = 0; j < context3->LookaheadGlyphCount; j++)
-               if (get_coverage_index (context3->LookAhead + j,
-                                       gstring->glyphs[fore_gidx + j].glyph_id)
-                   < 0)
+                 if (gidx < rule->BacktrackGlyphCount
+                     || (gidx + rule->InputGlyphCount
+                         + rule->LookaheadGlyphCount) > gstring->used)
+                   continue;
+                 if (match_chain_classes (gstring, gidx, flag,
+                                          &context2->BacktrackClassDef,
+                                          &context2->InputClassDef,
+                                          &context2->LookaheadClassDef,
+                                          rule) < 0)
+                   continue;
+                 orig_used = gstring->used;
+                 for (k = 0; k < rule->LookupCount; k++)
+                   lookup_gsub (otf, lookup_list,
+                                rule->LookupRecord[k].LookupListIndex,
+                                gstring,
+                                gidx + rule->LookupRecord[k].SequenceIndex,
+                                alternate_subst);
+                 gidx += rule->InputGlyphCount + (gstring->used - orig_used);
                  break;
-             if (j < context3->LookaheadGlyphCount)
-               continue;
+               }
+           }
+         else
+           {
+             OTF_GSUB_ChainContext3 *context3 = &subtable->u.chain_context3;
+             int orig_used;
+             int j;
 
+             if (gidx < context3->BacktrackGlyphCount
+                 || (gidx + context3->InputGlyphCount
+                     + context3->LookaheadGlyphCount) > gstring->used)
+               continue;
+             if (match_chain_coverages (gstring, gidx, flag, context3) < 0)
+               continue;
              orig_used = gstring->used;
-             for (j = 0; j < context3->SubstCount; j++)
-               lookup_gsub (lookup_list,
-                            context3->SubstLookupRecord[j].LookupListIndex,
+             for (j = 0; j < context3->LookupCount; j++)
+               lookup_gsub (otf, lookup_list,
+                            context3->LookupRecord[j].LookupListIndex,
                             gstring,
-                            gidx + context3->SubstLookupRecord[j].SequenceIndex);
+                            gidx + context3->LookupRecord[j].SequenceIndex,
+                            alternate_subst);
              gidx += context3->InputGlyphCount + (gstring->used - orig_used);
            }
          break;
 
+       case 8:
+         {
+           OTF_GSUB_ReverseChain1 *reverse = &subtable->u.reverse_chain1;
+           int back_gidx = gidx + 1 + reverse->BacktrackGlyphCount;
+           int ahead_gidx = gidx - reverse->LookaheadGlyphCount;
+           int j;
+
+           if (back_gidx > gstring->used || ahead_gidx < 0)
+             break;
+
+           for (j = 0; j < reverse->BacktrackGlyphCount; j++)
+             if (get_coverage_index (reverse->Backtrack + j,
+                                     gstring->glyphs[gidx + 1 + j].glyph_id)
+                 < 0)
+               break;
+           if (j < reverse->BacktrackGlyphCount)
+             continue;
+           for (j = 0; j < reverse->LookaheadGlyphCount; j++)
+             if (get_coverage_index (reverse->LookAhead + j,
+                                     gstring->glyphs[gidx - 1 - j].glyph_id)
+                 < 0)
+               break;
+           if (j < reverse->LookaheadGlyphCount)
+             continue;
+           g->glyph_id = reverse->Substitute[coverage_idx];
+           gidx--;
+         }
+
        default:
          continue;
        }
     }
   if (gidx == orig_gidx)
-    {
-      //printf ("not applied\n");
-      gidx++;
-    }
-  else
-    {
-      // printf ("done\n");
-    }
+    gidx++;
   return gidx;
 }
 
@@ -341,78 +757,274 @@ get_anchor (OTF_Anchor *anchor, OTF_ValueRecord *rec)
   return value_format;
 }
 
+static int
+gstring_insert_for_gpos (OTF_GlyphString *gstring, int gidx)
+{
+  int errret = -1;
+  int orig_gidx = gidx++;
+
+  while (gidx < gstring->used
+        && ! gstring->glyphs[gidx].glyph_id
+        && gstring->glyphs[gidx].positioning_type)
+    gidx++;
+  GSTRING_INSERT (gstring, gidx, 1);
+  gstring->glyphs[gidx] = gstring->glyphs[orig_gidx];
+  gstring->glyphs[gidx].glyph_id = 0;
+  return gidx;
+}
+
+static void
+print_anchor (char *head, OTF_Anchor *anchor)
+{
+  if (anchor->AnchorFormat == 1)
+    fprintf (stderr, " %s(X:%d Y:%d)", head,
+            anchor->XCoordinate, anchor->YCoordinate);
+  else if (anchor->AnchorFormat == 2)
+    fprintf (stderr, " %s(X:%d Y:%d AP:%d)", head,
+            anchor->XCoordinate, anchor->YCoordinate,
+            anchor->f.f1.AnchorPoint);
+  else
+    fprintf (stderr, " %s(X:%d Y:%d +alpha)", head,
+            anchor->XCoordinate, anchor->YCoordinate);
+}
+
+static void
+print_glyph_positioning (OTF_Glyph *g, int type)
+{
+  if (type)
+    fprintf (stderr, " %0X=", g->glyph_id);
+  switch (g->positioning_type)
+    {
+    case 1: case 2:
+      {
+       int format = g->f.f1.format;
+
+       if (format & OTF_XPlacement)
+         fprintf (stderr, "X:%d", g->f.f1.value->XPlacement);
+       if (format & OTF_XPlaDevice)
+         fprintf (stderr, "+alpha");
+       if (format & OTF_YPlacement)
+         fprintf (stderr, "Y:%d", g->f.f1.value->YPlacement);
+       if (format & OTF_YPlaDevice)
+         fprintf (stderr, "+alpha");
+       if (format & OTF_XAdvance)
+         fprintf (stderr, "X+:%d", g->f.f1.value->XAdvance);
+       if (format & OTF_XAdvDevice)
+         fprintf (stderr, "+alpha");
+       break;
+      }
+    case 3:
+      print_anchor ("entry", g->f.f3.entry_anchor);
+      print_anchor ("exit", g->f.f3.entry_anchor);
+      break;
+    case 4:
+      print_anchor ("mark", g->f.f4.mark_anchor);
+      print_anchor ("base", g->f.f4.base_anchor);
+      break;
+    case 5:
+      print_anchor ("mark", g->f.f5.mark_anchor);
+      print_anchor ("lig", g->f.f5.ligature_anchor);
+      break;
+    case 6:
+      print_anchor ("mark1", g->f.f6.mark1_anchor);
+      print_anchor ("mark2", g->f.f6.mark2_anchor);
+      break;
+    }
+}
 
 static int
 lookup_gpos (OTF_LookupList *lookup_list, unsigned lookup_list_index,
-            OTF_GlyphString *gstring, int gidx)
+            OTF_GlyphString *gstring, int gidx, int accumulate)
 {
   char *errfmt = "GPOS Looking up%s";
   int errret = -1;
   OTF_Lookup *lookup = lookup_list->Lookup + lookup_list_index;
-  unsigned int flag = lookup->LookupFlag;
+  unsigned int flag = (lookup->LookupFlag
+                      & (OTF_LookupFlagIgnoreMask | OTF_MarkAttachmentType));
   int orig_gidx = gidx;
   OTF_Glyph *g = gstring->glyphs + gidx;
   int i;
 
-  if (! g->glyph_id
-      || (g->GlyphClass
-         && (flag & (1 << g->GlyphClass))))
-    return (gidx + 1);
+  if (debug_flag)
+    fprintf (stderr, "[GPOS] glyph:%04X lookup:%02d",
+            g->glyph_id, lookup_list_index);
+  if (IGNORED_GLYPH (g, flag))
+    {
+      if (debug_flag)
+       fprintf (stderr, " glyph ignored\n");
+      return (gidx + 1);
+    }
 
   /* Try all subtables until one of them handles the current glyph.  */
   for (i = 0; i < lookup->SubTableCount && gidx == orig_gidx; i++)
     {
+      unsigned lookup_type = lookup->LookupType;
       OTF_LookupSubTableGPOS *subtable = lookup->SubTable.gpos + i;
       int coverage_idx;
+      int positioning_type;
+      enum OTF_ValueFormat format;
+      OTF_ValueRecord *value;
+      OTF_Anchor *anchor1, *anchor2;
+
+      if (lookup_type == 9)
+       {
+         OTF_GPOS_Extension1 *extension1 = &subtable->u.extension1;
 
-      // printf ("subtype:%d ", subtable->Format);
+         lookup_type = extension1->ExtensionLookupType;
+         subtable = extension1->ExtensionSubtable;
+       }
+
+      if (debug_flag)
+       fprintf (stderr, "/%d", lookup_type);
       if (subtable->Coverage.offset)
        {
          coverage_idx = get_coverage_index (&subtable->Coverage,
                                             g->glyph_id);
          if (coverage_idx < 0)
-           {
-             // printf ("not covererd ");
-             continue;
-           }
+           continue;
        }
 
-      switch (lookup->LookupType)
+      switch (lookup_type)
        {
        case 1:
-         OTF_ERROR (OTF_ERROR_GPOS_DRIVE, " (not yet supported)");
-
-       case 2:
-         if (gidx + 1 >= gstring->used)
-           continue;
+         positioning_type = lookup_type;
          if (subtable->Format == 1)
-           OTF_ERROR (OTF_ERROR_GPOS_DRIVE, " (not yet supported)");
+           {
+             OTF_GPOS_Single1 *single1 = &subtable->u.single1;
+
+             format = single1->ValueFormat;
+             value = &single1->Value;
+           }
          else if (subtable->Format == 2)
            {
-             OTF_GPOS_Pair2 *pair2 = &subtable->u.pair2;
-             unsigned class1, class2;
+             OTF_GPOS_Single2 *single2 = &subtable->u.single2;
 
-             printf ("GPOS 2-2: c:0x%x g:0x%x\n", g->c, g->glyph_id);
-             gidx++;
-             class1 = get_class_def (&pair2->ClassDef1, g->glyph_id);
-             class2 = get_class_def (&pair2->ClassDef2, g[1].glyph_id);
-             g->positioning_type = lookup->LookupType;
-             g->f.f2.format = pair2->ValueFormat1;
-             g->f.f2.value
-               = &pair2->Class1Record[class1].Class2Record[class2].Value1;
-             if (pair2->ValueFormat2)
-               {
-                 g++, gidx++;
-                 g->positioning_type = lookup->LookupType;
-                 g->f.f2.format = pair2->ValueFormat2;
-                 g->f.f2.value
-                   = &pair2->Class1Record[class1].Class2Record[class2].Value2;
-               }
+             format = single2->ValueFormat;
+             value = single2->Value + coverage_idx;
+           }
+         if (accumulate && g->positioning_type)
+           {
+             gidx = gstring_insert_for_gpos (gstring, gidx);         
+             g = gstring->glyphs + gidx;
            }
+         g->positioning_type = positioning_type;
+         g->f.f1.format = format;
+         g->f.f1.value = value;
+         if (debug_flag)
+           print_glyph_positioning (g, 0);
+         gidx++;
+         break;
+
+       case 2:
+         {
+           int next_gidx;
+           OTF_Glyph *nextg;
+
+           for (next_gidx = gidx + 1, nextg = gstring->glyphs + next_gidx;
+                next_gidx < gstring->used && IGNORED_GLYPH (nextg, flag);
+                next_gidx++, nextg++);
+
+           if (next_gidx >= gstring->used)
+             continue;
+           if (subtable->Format == 1)
+             {
+               OTF_GPOS_Pair1 *pair1 = &subtable->u.pair1;
+               OTF_PairSet *set = pair1->PairSet + coverage_idx;
+               int j;
+
+               for (j = 0; j < set->PairValueCount; j++)
+                 if (set->PairValueRecord[j].SecondGlyph == nextg->glyph_id)
+                   {
+                     if (pair1->ValueFormat1)
+                       {
+                         if (accumulate && g->positioning_type)
+                           {
+                             gidx = gstring_insert_for_gpos (gstring, gidx);
+                             g = gstring->glyphs + gidx;
+                             next_gidx += gidx - orig_gidx;
+                             nextg = gstring->glyphs + next_gidx;
+                           }
+                         g->positioning_type = lookup_type;
+                         g->f.f2.format = pair1->ValueFormat1;
+                         g->f.f2.value = &set->PairValueRecord[j].Value1;
+                         if (debug_flag)
+                           print_glyph_positioning (g, 1);
+                       }
+                     gidx = next_gidx;
+                     g = nextg;
+                     if (pair1->ValueFormat2)
+                       {
+                         if (accumulate && g->positioning_type)
+                           {
+                             gidx = gstring_insert_for_gpos (gstring, gidx);
+                             g = gstring->glyphs + gidx;
+                           }
+                         g->positioning_type = lookup_type;
+                         g->f.f2.format = pair1->ValueFormat2;
+                         g->f.f2.value = &set->PairValueRecord[j].Value2;
+                         if (debug_flag)
+                           print_glyph_positioning (g, 2);
+                       }
+                     break;
+                   }
+             }
+           else if (subtable->Format == 2)
+             {
+               OTF_GPOS_Pair2 *pair2 = &subtable->u.pair2;
+               unsigned class1, class2;
+
+               class1 = get_class_def (&pair2->ClassDef1, g->glyph_id);
+               class2 = get_class_def (&pair2->ClassDef2, nextg->glyph_id);
+               if (pair2->ValueFormat1)
+                 {
+                   if (accumulate && g->positioning_type)
+                     {
+                       gidx = gstring_insert_for_gpos (gstring, gidx);
+                       g = gstring->glyphs + gidx;
+                       next_gidx += gidx - orig_gidx;
+                       nextg = gstring->glyphs + next_gidx;
+                     }
+                   g->positioning_type = lookup_type;
+                   g->f.f2.format = pair2->ValueFormat1;
+                   g->f.f2.value
+                     = &pair2->Class1Record[class1].Class2Record[class2].Value1;
+                   if (debug_flag)
+                     print_glyph_positioning (g, 1);
+                 }
+               gidx = next_gidx;
+               g = nextg;
+               if (pair2->ValueFormat2)
+                 {
+                   if (accumulate && g->positioning_type)
+                     {
+                       gidx = gstring_insert_for_gpos (gstring, gidx);
+                       g = gstring->glyphs + gidx;
+                     }
+                   g->positioning_type = lookup_type;
+                   g->f.f2.format = pair2->ValueFormat2;
+                   g->f.f2.value
+                     = &pair2->Class1Record[class1].Class2Record[class2].Value2;
+                   if (debug_flag)
+                     print_glyph_positioning (g, 2);
+                 }
+             }
+         }
          break;
 
        case 3:
-         OTF_ERROR (OTF_ERROR_GPOS_DRIVE, " (not yet supported)");
+         {
+           OTF_GPOS_Cursive1 *cursive1 = &subtable->u.cursive1;
+         
+           g->positioning_type = lookup_type;
+           g->f.f3.entry_anchor
+             = &cursive1->EntryExitRecord[coverage_idx].EntryAnchor;
+           g->f.f3.exit_anchor
+             = &cursive1->EntryExitRecord[coverage_idx].ExitAnchor;
+           if (debug_flag)
+             print_glyph_positioning (g, 0);
+           gidx++;
+         }
+         break;
 
        case 4:
          if (gidx < 1)
@@ -421,29 +1033,290 @@ lookup_gpos (OTF_LookupList *lookup_list, unsigned lookup_list_index,
            {
              OTF_GPOS_MarkBase1 *mark_base1 = &subtable->u.mark_base1;
              OTF_MarkRecord *mark_record;
-             OTF_BaseRecord *base_record;
-             int coverage_idx_base
+             OTF_AnchorRecord *base_record;
+             OTF_Glyph *baseg;
+             int coverage_idx_base;
+             unsigned int this_flag = flag | OTF_IgnoreMarks;
+
+             for (baseg = g - 1;
+                  baseg >= gstring->glyphs && IGNORED_GLYPH (baseg, this_flag);
+                  baseg--);
+             if (baseg < gstring->glyphs)
+               continue;
+             coverage_idx_base
                = get_coverage_index (&mark_base1->BaseCoverage,
-                                     g[-1].glyph_id);
-
+                                     baseg->glyph_id);
              if (coverage_idx_base < 0)
                continue;
-             printf ("GPOS 4-1: c:0x%x g:0x%x\n", g->c, g->glyph_id);
              mark_record = mark_base1->MarkArray.MarkRecord + coverage_idx;
              base_record
-               = mark_base1->BaseArray.BaseRecord + coverage_idx_base;
+               = mark_base1->BaseArray.AnchorRecord + coverage_idx_base;
              g->f.f4.mark_anchor = &mark_record->MarkAnchor;
              g->f.f4.base_anchor
-               = &base_record->BaseAnchor[mark_record->Class];
-             g->positioning_type = lookup->LookupType;
+               = &base_record->Anchor[mark_record->Class];
+             g->positioning_type = lookup_type;
+             if (debug_flag)
+               print_glyph_positioning (g, 0);
+             gidx++;
+           }
+         break;
+
+       case 5:
+         if (gidx < 1)
+           continue;
+         if (subtable->Format == 1)
+           {
+             OTF_GPOS_MarkLig1 *mark_lig1 = &subtable->u.mark_lig1;
+             OTF_Glyph *ligg;
+             int coverage_idx_lig;
+             OTF_MarkRecord *mark_record;
+             OTF_LigatureAttach *attach;
+             int *num_class = alloca (sizeof (int) * mark_lig1->ClassCount);
+             int j;
+                                      
+             for (j = 0; j < mark_lig1->ClassCount; j++)
+               num_class[j] = 0;
+
+             for (ligg = g - 1;
+                  (ligg >= gstring->glyphs
+                   && (IGNORED_GLYPH (ligg, flag)
+                       || ligg->GlyphClass > OTF_GlyphClassLigature));
+                  ligg--)
+               if (ligg->positioning_type == 5
+                   && ligg->MarkAttachClass < mark_lig1->ClassCount)
+                 num_class[ligg->MarkAttachClass]++;
+             if (ligg < gstring->glyphs)
+               continue;
+             coverage_idx_lig
+               = get_coverage_index (&mark_lig1->LigatureCoverage,
+                                     ligg->glyph_id);
+             if (coverage_idx_lig < 0)
+               continue;
+             mark_record = mark_lig1->MarkArray.MarkRecord + coverage_idx;
+             g->MarkAttachClass = mark_record->Class;
+             attach = (mark_lig1->LigatureArray.LigatureAttach
+                       + coverage_idx_lig);
+             for (j = 0; j < attach->ComponentCount; j++)
+               {
+                 OTF_Anchor *lig_anchor
+                   = attach->ComponentRecord[j].LigatureAnchor;
+
+                 if (lig_anchor[mark_record->Class].AnchorFormat
+                     && num_class[mark_record->Class]-- == 0)
+                   {
+                     g->positioning_type = lookup_type;
+                     g->f.f5.mark_anchor = &mark_record->MarkAnchor;
+                     g->f.f5.ligature_anchor = lig_anchor + mark_record->Class;
+                     if (debug_flag)
+                       print_glyph_positioning (g, 0);
+                     gidx++;
+                     break;
+                   }
+               }
+           }
+         break;
+
+       case 6:
+         if (gidx < 1)
+           continue;
+         if (subtable->Format == 1)
+           {
+             OTF_GPOS_MarkMark1 *mark_mark1 = &subtable->u.mark_mark1;
+             OTF_MarkRecord *mark1_record;
+             OTF_AnchorRecord *mark2_record;
+             OTF_Glyph *prevg;
+             int coverage_idx_base;
+
+             for (prevg = g - 1;
+                  prevg >= gstring->glyphs && IGNORED_GLYPH (prevg, flag);
+                  prevg--);
+             if (prevg < gstring->glyphs)
+               continue;
+             coverage_idx_base
+               = get_coverage_index (&mark_mark1->Mark2Coverage,
+                                     prevg->glyph_id);
+             if (coverage_idx_base < 0)
+               continue;
+             mark1_record = mark_mark1->Mark1Array.MarkRecord + coverage_idx;
+             mark2_record
+               = mark_mark1->Mark2Array.AnchorRecord + coverage_idx_base;
+             g->f.f6.mark1_anchor = &mark1_record->MarkAnchor;
+             g->f.f6.mark2_anchor
+               = &mark2_record->Anchor[mark1_record->Class];
+             g->positioning_type = lookup_type;
+             if (debug_flag)
+               print_glyph_positioning (g, 0);
+             gidx++;
              break;
            }
-         else
-           OTF_ERROR (OTF_ERROR_GPOS_DRIVE, " (not yet supported)");
          break;
+
+       case 7:
+         if (subtable->Format == 1)
+           {
+             OTF_GPOS_Context1 *context1 = &subtable->u.context1;
+             OTF_RuleSet *set = context1->RuleSet + coverage_idx;
+             OTF_Rule *rule;
+             int orig_used;
+             int j, k;
+
+             for (j = 0; j < set->RuleCount; j++)
+               {
+                 rule = set->Rule + j;
+                 if (match_ids (gstring, gidx + 1, flag,
+                                rule->GlyphCount - 1, rule->Input) < 0)
+                   continue;
+                 orig_used = gstring->used;
+                 for (k = 0; k < rule->LookupCount; k++)
+                   lookup_gpos (lookup_list,
+                                rule->LookupRecord[k].LookupListIndex,
+                                gstring,
+                                gidx + rule->LookupRecord[k].SequenceIndex,
+                                accumulate);
+                 gidx += rule->GlyphCount + (gstring->used - orig_used);
+                 break;
+               }
+           }
+         else if (subtable->Format == 2)
+           {
+             OTF_GPOS_Context2 *context2 = &subtable->u.context2;
+             OTF_ClassSet *set;
+             OTF_ClassRule *rule;
+             unsigned class;
+             int orig_used;
+             int j, k;
+
+             class = get_class_def (&context2->ClassDef, g->glyph_id);
+             set = context2->ClassSet + class;
+             if (set)
+               for (j = 0; j < set->ClassRuleCnt; j++)
+                 {
+                   rule = set->ClassRule + j;
+                   if (match_classes (&context2->ClassDef,
+                                      gstring, gidx + 1, flag,
+                                      rule->GlyphCount - 1, rule->Class)
+                       < 0)
+                     continue;
+                   orig_used = gstring->used;
+                   for (k = 0; k < rule->LookupCount; k++)
+                     lookup_gpos (lookup_list,
+                                  rule->LookupRecord[k].LookupListIndex,
+                                  gstring,
+                                  gidx + rule->LookupRecord[k].SequenceIndex,
+                                  accumulate);
+                   gidx += rule->GlyphCount + (gstring->used - orig_used);
+                   break;
+                 }
+           }
+         else                  /* subtable->Format == 3 */
+           {
+             OTF_GPOS_Context3 *context3 = &subtable->u.context3;
+             int orig_used;
+             int j;
+
+             if (match_coverages (gstring, gidx + 1, flag,
+                                  context3->GlyphCount - 1,
+                                  context3->Coverage + 1) < 0)
+               continue;
+             orig_used = gstring->used;
+             for (j = 0; j < context3->LookupCount; j++)
+               lookup_gpos (lookup_list,
+                            context3->LookupRecord[j].LookupListIndex,
+                            gstring,
+                            gidx + context3->LookupRecord[j].SequenceIndex,
+                            accumulate);
+             gidx += context3->GlyphCount + (gstring->used - orig_used);
+           }
+         break;
+
+       case 8:
+         if (subtable->Format == 1)
+           {
+             OTF_GPOS_ChainContext1 *context1 = &subtable->u.chain_context1;
+             OTF_ChainRuleSet *set = context1->ChainRuleSet + coverage_idx;
+             int orig_used;
+             int j, k;
              
-       case 6:
-         OTF_ERROR (OTF_ERROR_GPOS_DRIVE, " (not yet supported)");
+             for (j = 0; j < set->ChainRuleCount; j++)
+               {
+                 OTF_ChainRule *rule = set->ChainRule + j;
+
+                 if (gidx < rule->BacktrackGlyphCount
+                     || (gidx + rule->InputGlyphCount
+                         + rule->LookaheadGlyphCount) > gstring->used)
+                   continue;
+                 if (match_chain_ids (gstring, gidx, flag, rule) < 0)
+                   continue;
+                 orig_used = gstring->used;
+                 for (k = 0; k < rule->LookupCount; k++)
+                   lookup_gpos (lookup_list,
+                                rule->LookupRecord[k].LookupListIndex,
+                                gstring,
+                                gidx + rule->LookupRecord[k].SequenceIndex,
+                                accumulate);
+                 gidx += rule->InputGlyphCount + (gstring->used - orig_used);
+                 break;
+               }
+           }
+         else if (subtable->Format == 2)
+           {
+             OTF_GPOS_ChainContext2 *context2 = &subtable->u.chain_context2;
+             OTF_ChainClassSet *set;
+             unsigned class;
+             int j;
+             int orig_used;
+
+             class = get_class_def (&context2->InputClassDef, g->glyph_id);
+             set = context2->ChainClassSet + class;
+             for (j = 0; j < set->ChainClassRuleCnt; j++)
+               {
+                 OTF_ChainClassRule *rule = set->ChainClassRule + j;
+                 int k;
+
+                 if (gidx < rule->BacktrackGlyphCount
+                     || (gidx + rule->InputGlyphCount
+                         + rule->LookaheadGlyphCount) > gstring->used)
+                   continue;
+                 if (match_chain_classes (gstring, gidx, flag,
+                                          &context2->BacktrackClassDef,
+                                          &context2->InputClassDef,
+                                          &context2->LookaheadClassDef,
+                                          rule) < 0)
+                   continue;
+                 orig_used = gstring->used;
+                 for (k = 0; k < rule->LookupCount; k++)
+                   lookup_gpos (lookup_list,
+                                rule->LookupRecord[k].LookupListIndex,
+                                gstring,
+                                gidx + rule->LookupRecord[k].SequenceIndex,
+                                accumulate);
+                 gidx += rule->InputGlyphCount + (gstring->used - orig_used);
+                 break;
+               }
+           }
+         else if (subtable->Format == 3)
+           {
+             OTF_GPOS_ChainContext3 *context3 = &subtable->u.chain_context3;
+             int orig_used;
+             int j;
+
+             if (gidx < context3->BacktrackGlyphCount
+                 || (gidx + context3->InputGlyphCount
+                     + context3->LookaheadGlyphCount) > gstring->used)
+               continue;
+             if (match_chain_coverages (gstring, gidx, flag, context3) < 0)
+               continue;
+             orig_used = gstring->used;
+             for (j = 0; j < context3->LookupCount; j++)
+               lookup_gpos (lookup_list,
+                            context3->LookupRecord[j].LookupListIndex,
+                            gstring,
+                            gidx + context3->LookupRecord[j].SequenceIndex,
+                            accumulate);
+             gidx += context3->InputGlyphCount + (gstring->used - orig_used);
+           }
+         else
+           OTF_ERROR (OTF_ERROR_GPOS_DRIVE, " (invalid subformat)");
          break;
 
        default:
@@ -452,72 +1325,402 @@ lookup_gpos (OTF_LookupList *lookup_list, unsigned lookup_list_index,
     }
   if (gidx == orig_gidx)
     {
-      // printf ("not applied\n");
+      if (debug_flag)
+       fprintf (stderr, " no match\n");
       gidx++;
     }
-  else
+  else if (debug_flag)
+    fprintf (stderr, "\n");
+  return gidx;
+}
+
+static unsigned
+lookup_encoding_0 (int c, OTF_EncodingSubtable *sub)
+{
+  return ((c < 0 || c >= 256)
+         ? 0
+         : sub->f.f0->glyphIdArray[c]);
+}
+
+static unsigned
+lookup_encoding_2 (int c, OTF_EncodingSubtable *sub)
+{
+  return 0;
+}
+
+static unsigned
+lookup_encoding_4 (int c, OTF_EncodingSubtable *sub)
+{
+  int segCount, i;
+  OTF_EncodingSubtable4 *sub4;
+
+  if (c < 0)
+    return 0;
+  sub4 = sub->f.f4;
+  segCount = sub4->segCountX2 / 2;
+  for (i = 0; i < segCount; i++)
     {
-      // printf ("done\n");
+      OTF_cmapSegment *seg = sub4->segments + i;
+
+      if (c >= seg->startCount && c <= seg->endCount)
+       {
+         if (seg->idRangeOffset == 0xFFFF)
+           return c + seg->idDelta;
+         else
+           return sub4->glyphIdArray[seg->idRangeOffset
+                                     + (c - seg->startCount)];
+       }
     }
-  return gidx;
+  return 0;
 }
 
-static int
-lookup_cmap (OTF_cmap *cmap, int c)
+static unsigned
+lookup_encoding_6 (int c, OTF_EncodingSubtable *sub)
 {
-  int i;
+  return 0;
+}
+
+static unsigned
+lookup_encoding_8 (int c, OTF_EncodingSubtable *sub)
+{
+  return 0;
+}
 
-  if (! cmap || ! cmap->Unicode)
+static unsigned
+lookup_encoding_10 (int c, OTF_EncodingSubtable *sub)
+{
+  return 0;
+}
+
+static unsigned
+lookup_encoding_12 (int c, OTF_EncodingSubtable *sub)
+{
+  OTF_EncodingSubtable12 *sub12;
+  OTF_cmapGroup *g, *gend;
+
+  if (c < 0)
     return 0;
+  sub12 = sub->f.f12;
+  g = sub12->Groups;
+  gend = sub12->Groups + sub12->nGroups;
+  while (g < gend)
+    {
+      if (g->startCharCode <= c && c <= g->endCharCode)
+       return (g->startGlyphID + (c - g->startCharCode));
+      g++;
+    }
+  return 0;
+}
+
+typedef unsigned (*lookup_cmap_func) (int, OTF_EncodingSubtable *);
+
+static lookup_cmap_func lookup_cmap_func_table[] =
+  {
+    lookup_encoding_0, lookup_encoding_2, lookup_encoding_4, lookup_encoding_6,
+    lookup_encoding_8, lookup_encoding_10, lookup_encoding_12
+  };
+
+static unsigned
+get_GlyphID (OTF_cmap *cmap, int c)
+{
+  OTF_EncodingSubtable *sub;
+  lookup_cmap_func lookupper;
+
+  if (c < 0x10000 && cmap->unicode_table)
+    return cmap->unicode_table[c];
+  if (cmap->table_index < 0)
+    return 0;
+  sub = &cmap->EncodingRecord[cmap->table_index].subtable;
+  lookupper = lookup_cmap_func_table[sub->format / 2];
+  return lookupper (c, sub);
+}
 
-  switch (cmap->Unicode->subtable.format)
+static OTF_GlyphID
+get_uvs_glyph (OTF_cmap *cmap, OTF_EncodingSubtable14 *sub14, int c1, int c2)
+{
+  unsigned nRecords = sub14->nRecords;
+  OTF_VariationSelectorRecord *record;
+  unsigned i;
+
+  for (i = 0; i < nRecords; i++)
     {
-    case 0:
-      break;
+      record = &sub14->Records[i];
+      if (record->varSelector == c2)
+       {
+         if (record->defaultUVSOffset)
+           {
+             OTF_UnicodeValueRange *uVRs = record->unicodeValueRanges;
+             unsigned numUVRs = record->numUnicodeValueRanges;
+             unsigned top = numUVRs, bottom = 0, middle;
 
-    case 4:
-      {
-       OTF_EncodingSubtable4 *sub4 = cmap->Unicode->subtable.f.f4;
-       int segCount = sub4->segCountX2 / 2;
+             if (uVRs[0].startUnicodeValue <= c1)
+               {
+                 unsigned additionalCount, startUnicodeValue;
+
+                 for (;;)
+                   {
+                     middle = (top + bottom) / 2;
+                     if (c1 < uVRs[middle].startUnicodeValue)
+                       top = middle;
+                     else if (bottom == middle)
+                       break;
+                     else
+                       bottom = middle;
+                   }
+                 startUnicodeValue = uVRs[bottom].startUnicodeValue;
+                 additionalCount = uVRs[bottom].additionalCount;
+                 if (c1 <= startUnicodeValue + additionalCount)
+                   return get_GlyphID (cmap, c1);
+               }
+           }
+         if (record->nonDefaultUVSOffset)
+           {
+             OTF_UVSMapping *uvsMappings = record->uvsMappings;
+             unsigned numUVSMs = record->numUVSMappings;
+             unsigned top = numUVSMs, bottom = 0, middle;
 
-       for (i = 0; i < segCount; i++)
-         if (c <= sub4->segments[i].endCount)
-           break;
-       if (i == segCount || c < sub4->segments[i].startCount)
+             if (uvsMappings[0].unicodeValue <= c1)
+               {
+                 for (;;)
+                   {
+                     middle = (top + bottom) / 2;
+                     if (c1 < uvsMappings[middle].unicodeValue)
+                       top = middle;
+                     else if (bottom == middle)
+                       break;
+                     else
+                       bottom = middle;
+                   }
+                 if (uvsMappings[bottom].unicodeValue == c1)
+                   return uvsMappings[bottom].glyphID;
+               }
+           }
          return 0;
-       if (sub4->segments[i].idRangeOffset == 0xFFFF)
-         return c + sub4->segments[i].idDelta;
-       return sub4->glyphIdArray[sub4->segments[i].idRangeOffset
-                                 + (c - sub4->segments[i].startCount)];
-      }
-      break;
+       }
     }
   return 0;
 }
 
+static void
+check_cmap_uvs (OTF_cmap *cmap, OTF_GlyphString *gstring, int idx)
+{  
+  OTF_EncodingSubtable14 *sub14;
+  int c1 = gstring->glyphs[idx - 1].c;
+  int c2 = gstring->glyphs[idx].c;
+  OTF_GlyphID code;
+  int i;
+
+  gstring->glyphs[idx].glyph_id = 0;
+  for (i = 0; i < cmap->numTables; i++)
+    if (cmap->EncodingRecord[i].subtable.format == 14)
+      break;
+  if (i == cmap->numTables)
+    return;
+  code = get_uvs_glyph (cmap, cmap->EncodingRecord[i].subtable.f.f14, c1, c2);
+  if (code == 0)
+    return;
+  gstring->glyphs[idx - 1].glyph_id = code;
+  gstring->glyphs[idx - 1].f.index.to = gstring->glyphs[idx].f.index.to;
+  gstring->used--;
+  memmove (gstring->glyphs + idx, gstring->glyphs + idx + 1,
+          sizeof (OTF_Glyph) * (gstring->used - idx));
+}
+
 \f
 
-/* APIs */
+/* GDEF */
+/* Table of GlyphClass and MarkAttackClass.
+
+   For the Nth element CHAR, CHAR and the succeeding characters
+   (before CHAR of the next element) has GlyphClass C (= (N % 2) ? 3 : 1).
+
+   This table is generated from the General Category (GC) property of
+   characters defined in the Unicode Character Database.  */
+
+static int glyph_class_table[] =
+  { 0x00000, 0x00300, 0x00370, 0x00483, 0x00487, 0x00488, 0x0048A, 0x00591,
+    0x005BE, 0x005BF, 0x005C0, 0x005C1, 0x005C3, 0x005C4, 0x005C6, 0x005C7,
+    0x005C8, 0x00610, 0x00616, 0x0064B, 0x0065F, 0x00670, 0x00671, 0x006D6,
+    0x006DD, 0x006DE, 0x006E5, 0x006E7, 0x006E9, 0x006EA, 0x006EE, 0x00711,
+    0x00712, 0x00730, 0x0074B, 0x007A6, 0x007B1, 0x007EB, 0x007F4, 0x00901,
+    0x00904, 0x0093C, 0x0093D, 0x0093E, 0x0094E, 0x00951, 0x00955, 0x00962,
+    0x00964, 0x00981, 0x00984, 0x009BC, 0x009BD, 0x009BE, 0x009C5, 0x009C7,
+    0x009CE, 0x009D7, 0x009D8, 0x009E2, 0x009E4, 0x00A01, 0x00A04, 0x00A3C,
+    0x00A3D, 0x00A3E, 0x00A4E, 0x00A70, 0x00A72, 0x00A81, 0x00A84, 0x00ABC,
+    0x00ABD, 0x00ABE, 0x00ACE, 0x00AE2, 0x00AE4, 0x00B01, 0x00B04, 0x00B3C,
+    0x00B3D, 0x00B3E, 0x00B44, 0x00B47, 0x00B58, 0x00B82, 0x00B83, 0x00BBE,
+    0x00BCE, 0x00BD7, 0x00BD8, 0x00C01, 0x00C04, 0x00C3E, 0x00C45, 0x00C46,
+    0x00C57, 0x00C82, 0x00C84, 0x00CBC, 0x00CBD, 0x00CBE, 0x00CC5, 0x00CC6,
+    0x00CCE, 0x00CD5, 0x00CD7, 0x00CE2, 0x00CE4, 0x00D02, 0x00D04, 0x00D3E,
+    0x00D44, 0x00D46, 0x00D4E, 0x00D57, 0x00D58, 0x00D82, 0x00D84, 0x00DCA,
+    0x00DCB, 0x00DCF, 0x00DD7, 0x00DD8, 0x00DF4, 0x00E31, 0x00E32, 0x00E34,
+    0x00E3B, 0x00E47, 0x00E4F, 0x00EB1, 0x00EB2, 0x00EB4, 0x00EBD, 0x00EC8,
+    0x00ECE, 0x00F18, 0x00F1A, 0x00F35, 0x00F36, 0x00F37, 0x00F38, 0x00F39,
+    0x00F3A, 0x00F3E, 0x00F40, 0x00F71, 0x00F85, 0x00F86, 0x00F88, 0x00F90,
+    0x00FBD, 0x00FC6, 0x00FC7, 0x0102C, 0x0103A, 0x01056, 0x0105A, 0x0135F,
+    0x01360, 0x01712, 0x01715, 0x01732, 0x01735, 0x01752, 0x01754, 0x01772,
+    0x01774, 0x017B6, 0x017D4, 0x017DD, 0x017DE, 0x0180B, 0x0180E, 0x018A9,
+    0x018AA, 0x01920, 0x0193C, 0x019B0, 0x019C1, 0x019C8, 0x019CA, 0x01A17,
+    0x01A1C, 0x01B00, 0x01B05, 0x01B34, 0x01B45, 0x01B6B, 0x01B74, 0x01DC0,
+    0x01E00, 0x020D0, 0x020F0, 0x0302A, 0x03030, 0x03099, 0x0309B, 0x0A802,
+    0x0A803, 0x0A806, 0x0A807, 0x0A80B, 0x0A80C, 0x0A823, 0x0A828, 0x0FB1E,
+    0x0FB1F, 0x0FE00, 0x0FE10, 0x0FE20, 0x0FE24, 0x10A01, 0x10A10, 0x10A38,
+    0x10A40, 0x1D165, 0x1D16A, 0x1D16D, 0x1D173, 0x1D17B, 0x1D183, 0x1D185,
+    0x1D18C, 0x1D1AA, 0x1D1AE, 0x1D242, 0x1D245, 0xE0100, 0xE01F0 };
+
+int get_class_def_auto (int c)
+{
+  static int table_size
+    = sizeof glyph_class_table / sizeof glyph_class_table[0];
+  int low, high, mid;
+
+  if (c >= glyph_class_table[table_size - 1])
+    return 0;
+  low = 0;
+  high = table_size - 1;
+  while (1)
+    {
+      mid = (low + high) / 2;
+      if (c < glyph_class_table[mid])
+       high = mid - 1;
+      else if (c >= glyph_class_table[mid + 1])
+       low = mid + 1;
+      else
+       break;
+    }
+  return ((mid % 2) ? 3 : 1);
+}
+
+\f
+
+/* API */
+
+#define UVS_P(C)       \
+  (((C) >= 0xFE00 && (C) <= 0xFE0F) || ((C) >= 0xE0100 && (C) <= 0xE01EF))
 
 int
 OTF_drive_cmap (OTF *otf, OTF_GlyphString *gstring)
 {
   OTF_cmap *cmap;
   int i;
+  OTF_EncodingSubtable *sub;
+  lookup_cmap_func lookupper;
 
   if (! otf->cmap
       && OTF_get_table (otf, "cmap") < 0)
     return -1;
 
   cmap = otf->cmap;
+  if (cmap->table_index < 0)
+    lookupper = NULL;
+  else
+    {
+      sub = &cmap->EncodingRecord[cmap->table_index].subtable;
+      lookupper = lookup_cmap_func_table[sub->format / 2];
+    }
   for (i = 0; i < gstring->used; i++)
-      gstring->glyphs[i].glyph_id = lookup_cmap (cmap, gstring->glyphs[i].c);
-
+    if (! gstring->glyphs[i].glyph_id)
+      {
+       int c = gstring->glyphs[i].c;
+       if (c < 32 || ! cmap->unicode_table)
+         gstring->glyphs[i].glyph_id = 0;
+       else if (UVS_P (c) && i > 0)
+         check_cmap_uvs (cmap, gstring, i);
+       else if (c < 0x10000)
+         gstring->glyphs[i].glyph_id = cmap->unicode_table[c];
+       else if (lookupper)
+         gstring->glyphs[i].glyph_id = lookupper (c, sub);
+      }
   return 0;
 }
 
 
 int
+OTF_drive_cmap2 (OTF *otf, OTF_GlyphString *gstring,
+                int platform_id, int encoding_id)
+{
+  OTF_cmap *cmap;
+  int i;
+  char *errfmt = "CMAP Looking up%s";
+  int errret = -1;
+  OTF_EncodingRecord *enc;
+  lookup_cmap_func lookupper;
+
+  if (! otf->cmap
+      && OTF_get_table (otf, "cmap") < 0)
+    return -1;
+
+  cmap = otf->cmap;
+  for (i = 0; i < cmap->numTables; i++)
+    if (cmap->EncodingRecord[i].platformID == platform_id
+       && cmap->EncodingRecord[i].encodingID == encoding_id)
+      break;
+  if (i == cmap->numTables)
+    OTF_ERROR (OTF_ERROR_CMAP_DRIVE, " (unknown platformID/encodingID)");
+  enc = cmap->EncodingRecord + i;
+  if (enc->subtable.format > 12)
+    OTF_ERROR (OTF_ERROR_CMAP_DRIVE, " (invalid format)");
+  lookupper = lookup_cmap_func_table[enc->subtable.format / 2];
+
+  for (i = 0; i < gstring->used; i++)
+    if (! gstring->glyphs[i].glyph_id)
+      {
+       int c = gstring->glyphs[i].c;
+       if (c < 32 || ! cmap->unicode_table)
+         gstring->glyphs[i].glyph_id = 0;
+       else if (UVS_P (c) && i > 0)
+         check_cmap_uvs (cmap, gstring, i);
+       else if (c < 0x10000)
+         gstring->glyphs[i].glyph_id = cmap->unicode_table[c];
+       else
+         gstring->glyphs[i].glyph_id = lookupper (c, &enc->subtable);
+      }
+}
+
+
+int
+OTF_get_unicode (OTF *otf, OTF_GlyphID code)
+{
+  if (! otf->cmap
+      && OTF_get_table (otf, "cmap") < 0)
+    return 0;
+  if (code == 0
+      || code > otf->cmap->max_glyph_id
+      || ! otf->cmap->decode_table)
+    return 0;
+  return otf->cmap->decode_table[code];
+}
+
+int
+OTF_get_variation_glyphs (OTF *otf, int c, OTF_GlyphID code[256])
+{
+  int i, n;
+  OTF_cmap *cmap;
+  OTF_EncodingSubtable14 *sub14;
+
+  memset (code, 0, sizeof (OTF_GlyphID) * 256);
+  if (! otf->cmap
+      && OTF_get_table (otf, "cmap") < 0)
+    return 0;
+  cmap = otf->cmap;
+  for (i = 0; i < cmap->numTables; i++)
+    if (cmap->EncodingRecord[i].subtable.format == 14)
+      break;
+  if (i == cmap->numTables)
+    return 0;
+  sub14 = cmap->EncodingRecord[i].subtable.f.f14;
+  for (i = 0, n = 0; i < 256; i++)
+    {
+      int uvs = (i < 16 ? 0xFE00 + i : 0xE0100 + (i - 16));
+
+      if ((code[i] = get_uvs_glyph (cmap, sub14, c, uvs)))
+       n++;
+    }
+  return n;
+}
+
+
+int
 OTF_drive_gdef (OTF *otf, OTF_GlyphString *gstring)
 {
   OTF_GDEF *gdef;
@@ -533,6 +1736,10 @@ OTF_drive_gdef (OTF *otf, OTF_GlyphString *gstring)
       gstring->glyphs[i].GlyphClass
        = get_class_def (&gdef->glyph_class_def,
                         gstring->glyphs[i].glyph_id);
+  else
+    for (i = 0; i < gstring->used; i++)
+      gstring->glyphs[i].GlyphClass
+       = get_class_def_auto (gstring->glyphs[i].c);
 
   if (gdef->mark_attach_class_def.offset)
     for (i = 0; i < gstring->used; i++)
@@ -543,48 +1750,69 @@ OTF_drive_gdef (OTF *otf, OTF_GlyphString *gstring)
   return 0;
 }
 
-
-int
-OTF_drive_gsub (OTF *otf, OTF_GlyphString *gstring,
-               char *script, char *language, char *features)
+static int
+OTF_drive_gsub_internal (OTF *otf, OTF_GlyphString *gstring,
+                        const char *script, const char *language,
+                        const char *features,
+                        int alternate_subst)
 {
   char *errfmt = "GSUB driving%s";
   int errret = -1;
   OTF_GSUB *gsub;
   OTF_LangSys *LangSys;
-  int nfeatures;
-  int *feature_index;
-  int i, j;
+  char *lookup_flags;
+  int i;
 
-  if (! otf->gsub
-      && OTF_get_table (otf, "GSUB") < 0)
-    return -1;
+  for (i = 0; i < gstring->used; i++)
+    {
+      gstring->glyphs[i].positioning_type = 0;
+      gstring->glyphs[i].f.index.from = gstring->glyphs[i].f.index.to = i;
+    }
+
+  if (OTF_get_table (otf, "GSUB") < 0)
+    return errret;
   gsub = otf->gsub;
+  if (gsub->FeatureList.FeatureCount == 0
+      || gsub->LookupList.LookupCount == 0)
+    return 0;
 
   LangSys = get_langsys (&gsub->ScriptList, script, language);
   if (! LangSys)
-    return -1;
+    return errret;
 
-  feature_index = alloca (sizeof (int) * gsub->FeatureList.FeatureCount);
-  if (! feature_index)
+  lookup_flags = alloca (gsub->LookupList.LookupCount);
+  if (! lookup_flags
+      || setup_lookup_flags (&gsub->LookupList, &gsub->FeatureList, LangSys,
+                            features, lookup_flags) < 0)
     OTF_ERROR (OTF_ERROR_MEMORY, " feature list");
 
-  nfeatures = get_feature_index (LangSys, &gsub->FeatureList,
-                                features, feature_index);
-  if (nfeatures == 0)
-    OTF_ERROR (OTF_ERROR_GSUB_DRIVE, " no feature");
-
-  for (i = 0; i < nfeatures; i++)
+  for (i = 0; i < gsub->LookupList.LookupCount; i++)
     {
-      OTF_Feature *feature = gsub->FeatureList.Feature + feature_index[i];
+      int gidx;
 
-      for (j = 0; j < feature->LookupCount; j++)
-       {
-         int gidx = 0;
+      if (! lookup_flags[i]) continue;
 
+      if (gsub->LookupList.Lookup[i].LookupType != 8)
+       {
+         gidx = 0;
          while (gidx < gstring->used)
-           gidx = lookup_gsub (&gsub->LookupList, feature->LookupListIndex[j],
-                               gstring, gidx);
+           {
+             gidx = lookup_gsub (otf, &gsub->LookupList, i, gstring, gidx,
+                                 alternate_subst);
+             if (gidx < 0)
+               return errret;
+           }
+       }
+      else
+       {
+         gidx = gstring->used - 1;
+         while (gidx >= 0)
+           {
+             gidx = lookup_gsub (otf, &gsub->LookupList, i, gstring, gidx,
+                                 alternate_subst);
+             if (gidx < 0)
+               return errret;
+           }
        }
     }
 
@@ -592,46 +1820,58 @@ OTF_drive_gsub (OTF *otf, OTF_GlyphString *gstring,
 }
 
 int
-OTF_drive_gpos (OTF *otf, OTF_GlyphString *gstring,
-               char *script, char *language, char *features)
+OTF_drive_gsub (OTF *otf, OTF_GlyphString *gstring,
+               const char *script, const char *language, const char *features)
+{
+  if (! otf->cmap)
+    OTF_get_table (otf, "cmap");
+  return OTF_drive_gsub_internal (otf, gstring, script, language, features, 0);
+}
+
+int
+OTF_drive_gpos_internal (OTF *otf, OTF_GlyphString *gstring,
+                        const char *script, const char *language,
+                        const char *features,
+                        int accumulate)
 {
   char *errfmt = "GPOS driving%s";
   int errret = -1;
   OTF_GPOS *gpos;
   OTF_LangSys *LangSys;
-  int nfeatures;
-  int *feature_index;
-  int i, j;
+  char *lookup_flags;
+  int i, n;
 
-  if (! otf->gpos
-      && OTF_get_table (otf, "GPOS") < 0)
-    return -1;
+  for (i = 0; i < gstring->used; i++)
+    gstring->glyphs[i].positioning_type = 0;
+
+  if (OTF_get_table (otf, "GPOS") < 0)
+    return errret;
   gpos = otf->gpos;
+  if (gpos->FeatureList.FeatureCount == 0
+      || gpos->LookupList.LookupCount == 0)
+    return 0;
 
   LangSys = get_langsys (&gpos->ScriptList, script, language);
   if (! LangSys)
-    return -1;
+    return errret;
 
-  feature_index = alloca (sizeof (int) * gpos->FeatureList.FeatureCount);
-  if (! feature_index)
+  lookup_flags = alloca (gpos->LookupList.LookupCount);
+  if (! lookup_flags
+      || setup_lookup_flags (&gpos->LookupList, &gpos->FeatureList, LangSys,
+                            features, lookup_flags) < 0)
     OTF_ERROR (OTF_ERROR_MEMORY, " feature list");
 
-  nfeatures = get_feature_index (LangSys, &gpos->FeatureList,
-                                features, feature_index);
-  if (nfeatures == 0)
-    OTF_ERROR (OTF_ERROR_GSUB_DRIVE, " no feature");
-
-  for (i = 0; i < nfeatures; i++)
+  for (i = 0; i < gpos->LookupList.LookupCount; i++)
     {
-      OTF_Feature *feature = gpos->FeatureList.Feature + feature_index[i];
+      int gidx = 0;
 
-      for (j = 0; j < feature->LookupCount; j++)
-       {
-         int gidx = 0;
+      if (! lookup_flags[i]) continue;
 
-         while (gidx < gstring->used)
-           gidx = lookup_gpos (&gpos->LookupList, feature->LookupListIndex[j],
-                               gstring, gidx);
+      while (gidx < gstring->used)
+       {
+         gidx = lookup_gpos (&gpos->LookupList, i, gstring, gidx, accumulate);
+         if (gidx < 0)
+           return errret;
        }
     }
 
@@ -639,19 +1879,218 @@ OTF_drive_gpos (OTF *otf, OTF_GlyphString *gstring,
 }
 
 int
+OTF_drive_gpos (OTF *otf, OTF_GlyphString *gstring,
+               const char *script, const char *language, const char *features)
+{
+  if (! otf->cmap)
+    OTF_get_table (otf, "cmap");
+  return OTF_drive_gpos_internal (otf, gstring, script, language, features, 0);
+}
+
+int
+OTF_drive_gpos2 (OTF *otf, OTF_GlyphString *gstring,
+               const char *script, const char *language, const char *features)
+{
+  if (! otf->cmap)
+    OTF_get_table (otf, "cmap");
+  return OTF_drive_gpos_internal (otf, gstring, script, language, features, 1);
+}
+
+int
 OTF_drive_tables (OTF *otf, OTF_GlyphString *gstring,
-                 char *script, char *language,
-                 char *gsub_features, char *gpos_features)
+                 const char *script, const char *language,
+                 const char *gsub_features, const char *gpos_features)
 {
   if (OTF_drive_cmap (otf, gstring) < 0)
     return -1;
   if (OTF_drive_gdef (otf, gstring) < 0)
     return -1;
-  if ((! gsub_features || gsub_features[0])
+  if (gsub_features
       && OTF_drive_gsub (otf, gstring, script, language, gsub_features) < 0)
     return -1;
-  if ((! gpos_features || gpos_features[0])
+  if (gpos_features
       && OTF_drive_gpos (otf, gstring, script, language, gpos_features) < 0)
     return -1;
   return 0;
 }
+
+int
+OTF_drive_gsub_alternate (OTF *otf, OTF_GlyphString *gstring,
+                         const char *script, const char *language,
+                         const char *features)
+{
+  return OTF_drive_gsub_internal (otf, gstring, script, language, features, 1);
+}
+
+static int
+iterate_coverage (OTF *otf, const char *feature, 
+                 OTF_Feature_Callback callback,
+                 OTF_Coverage *coverage)
+{
+  int i;
+
+  if (coverage->CoverageFormat == 1)
+    {
+      for (i = 0; i < coverage->Count; i++)
+       if (callback (otf, feature, coverage->table.GlyphArray[i]) < 0)
+         return -1;
+    }
+  else
+    {
+      for (i = 0; i < coverage->Count; i++)
+       {
+         OTF_RangeRecord *range = coverage->table.RangeRecord + i;
+         unsigned id;
+         for (id = range->Start; id <= range->End; id++)
+           if (callback (otf, feature, id) < 0)
+             return -1;
+       }
+    }
+  return 0;
+}
+
+static int
+iterate_feature (OTF *otf, const char *feature,
+                OTF_Feature_Callback callback,
+                OTF_Lookup *lookup)
+{
+  int i, j, k, l;
+
+  for (i = 0; i < lookup->SubTableCount; i++)
+    {
+      unsigned lookup_type = lookup->LookupType;
+      OTF_LookupSubTableGSUB *subtable = lookup->SubTable.gsub + i;
+
+      if (lookup_type == 7)
+       {
+         OTF_GSUB_Extension1 *extension1 = &subtable->u.extension1;
+
+         lookup_type = extension1->ExtensionLookupType;
+         subtable = extension1->ExtensionSubtable;
+       }
+
+      if ((lookup_type >= 1 && lookup_type <= 3) || lookup_type == 8)
+       {
+         if (iterate_coverage (otf, feature, callback, &subtable->Coverage)
+             < 0)
+           return -1;
+       }
+      else if (lookup_type == 4)
+       {
+         OTF_GSUB_Ligature1 *lig1;
+
+         if (iterate_coverage (otf, feature, callback, &subtable->Coverage)
+             < 0)
+           return -1;
+         lig1 = &subtable->u.ligature1;
+         for (j = 0; j < lig1->LigSetCount; j++)
+           {
+             OTF_LigatureSet *ligset = lig1->LigatureSet + j;
+
+             for (k = 0; k < ligset->LigatureCount; k++)
+               {
+                 OTF_Ligature *lig = ligset->Ligature + k;
+                 for (l = 0; l < lig->CompCount - 1; l++)
+                   if (callback (otf, feature, lig->Component[l]) < 0)
+                     return -1;
+               }
+           }
+       }
+      else if (lookup_type == 6)
+       {
+         if (subtable->Format == 1)
+           {
+             OTF_GSUB_ChainContext1 *context1 = &subtable->u.chain_context1;
+             for (j = 0; j < context1->ChainRuleSetCount; j++)
+               {
+                 OTF_ChainRuleSet *set = context1->ChainRuleSet + j;
+                 for (k = 0; k < set->ChainRuleCount; k++)
+                   {
+                     OTF_ChainRule *rule = set->ChainRule + k;
+                     for (l = 0; l < rule->LookupCount; l++)
+                       {
+                         OTF_Lookup *lkup
+                           = (otf->gsub->LookupList.Lookup
+                              + rule->LookupRecord[l].LookupListIndex);
+                         if (iterate_feature (otf, feature, callback, lkup)
+                             < 0)
+                           return -1;
+                       }
+                   }
+               }
+           }
+         else if (subtable->Format == 2)
+           {
+             OTF_GSUB_ChainContext2 *context2 = &subtable->u.chain_context2;
+
+             for (j = 0; j < context2->ChainClassSetCnt; j++)
+               {
+                 OTF_ChainClassSet *set = context2->ChainClassSet + j;
+                 for (k = 0; k < set->ChainClassRuleCnt; j++)
+                   {
+                     OTF_ChainClassRule *rule = set->ChainClassRule + k;
+
+                     for (l = 0; l < rule->LookupCount; l++)
+                       {
+                         OTF_Lookup *lkup
+                           = (otf->gsub->LookupList.Lookup
+                              + rule->LookupRecord[k].LookupListIndex);
+                         if (iterate_feature (otf, feature, callback, lkup)
+                             < 0)
+                           return -1;
+                       }
+                   }
+               }
+           }
+         else
+           {
+             OTF_GSUB_ChainContext3 *context3 = &subtable->u.chain_context3;
+             for (j = 0; j < context3->LookupCount; j++)
+               {
+                 OTF_Lookup *lkup
+                   = (otf->gsub->LookupList.Lookup
+                      + context3->LookupRecord[j].LookupListIndex);
+                 if (iterate_feature (otf, feature, callback, lkup) < 0)
+                   return -1;
+               }
+           }
+       }
+    }
+  return 0;
+}
+
+int
+OTF_iterate_gsub_feature (OTF *otf, OTF_Feature_Callback callback,
+                         const char *script, const char *language,
+                         const char *feature)
+{
+  char *errfmt = "GSUB iterate feature%s";
+  int errret = -1;
+  int i;
+
+  OTF_GSUB *gsub;
+  OTF_LangSys *langsys;
+  char *lookup_flags;
+
+  if (OTF_get_table (otf, "GSUB") < 0)
+    return errret;
+  gsub = otf->gsub;
+  if (gsub->FeatureList.FeatureCount == 0
+      || gsub->LookupList.LookupCount == 0)
+    return 0;
+  langsys = get_langsys (&gsub->ScriptList, script, language);
+  if (! langsys)
+    return errret;
+  lookup_flags = alloca (gsub->LookupList.LookupCount);
+  if (! lookup_flags
+      || setup_lookup_flags (&gsub->LookupList, &gsub->FeatureList, langsys,
+                            feature, lookup_flags) < 0)
+    OTF_ERROR (OTF_ERROR_MEMORY, " feature");
+
+  for (i = 0; i < gsub->LookupList.LookupCount; i++)
+    if (lookup_flags[i])
+      if (iterate_feature (otf, feature, callback, gsub->LookupList.Lookup + i)
+         < 0)
+       return -1;
+  return 0;
+}