Add Harfbuzz to third_party and Skia support for such.

Harfbuzz is an open source library which is a unification of the Qt
and Pango shaping engines. We'll be using it on Chromium Linux to
perform complex text shaping.

Additionally, we add support for Harfbuzz into Skia, guarded by
SKIA_HARFBUZZ.

http://codereview.chromium.org/63035/show


git-svn-id: svn://svn.chromium.org/chrome/trunk/src@13214 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 1414 insertions, 0 deletions

diff --git a/third_party/harfbuzz/src/harfbuzz-open.c b/third_party/harfbuzz/src/harfbuzz-open.c
new file mode 100644
index 0000000..cde5465
--- /dev/null
+++ b/third_party/harfbuzz/src/harfbuzz-open.c
@@ -0,0 +1,1414 @@
+/*
+ * Copyright (C) 1998-2004  David Turner and Werner Lemberg
+ * Copyright (C) 2006  Behdad Esfahbod
+ *
+ * This is part of HarfBuzz, an OpenType Layout engine library.
+ *
+ * Permission is hereby granted, without written agreement and without
+ * license or royalty fees, to use, copy, modify, and distribute this
+ * software and its documentation for any purpose, provided that the
+ * above copyright notice and the following two paragraphs appear in
+ * all copies of this software.
+ *
+ * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
+ * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
+ * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
+ * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
+ * DAMAGE.
+ *
+ * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
+ * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
+ * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
+ * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
+ */
+
+#include "harfbuzz-impl.h"
+#include "harfbuzz-open-private.h"
+
+
+/***************************
+ * Script related functions
+ ***************************/
+
+
+/* LangSys */
+
+static HB_Error  Load_LangSys( HB_LangSys*  ls,
+			       HB_Stream     stream )
+{
+  HB_Error   error;
+  HB_UShort  n, count;
+  HB_UShort* fi;
+
+
+  if ( ACCESS_Frame( 6L ) )
+    return error;
+
+  ls->LookupOrderOffset    = GET_UShort();    /* should be 0 */
+  ls->ReqFeatureIndex      = GET_UShort();
+  count = ls->FeatureCount = GET_UShort();
+
+  FORGET_Frame();
+
+  ls->FeatureIndex = NULL;
+
+  if ( ALLOC_ARRAY( ls->FeatureIndex, count, HB_UShort ) )
+    return error;
+
+  if ( ACCESS_Frame( count * 2L ) )
+  {
+    FREE( ls->FeatureIndex );
+    return error;
+  }
+
+  fi = ls->FeatureIndex;
+
+  for ( n = 0; n < count; n++ )
+    fi[n] = GET_UShort();
+
+  FORGET_Frame();
+
+  return HB_Err_Ok;
+}
+
+
+static void  Free_LangSys( HB_LangSys*  ls )
+{
+  FREE( ls->FeatureIndex );
+}
+
+
+/* Script */
+
+static HB_Error  Load_Script( HB_ScriptTable*  s,
+			      HB_Stream    stream )
+{
+  HB_Error   error;
+  HB_UShort  n, m, count;
+  HB_UInt   cur_offset, new_offset, base_offset;
+
+  HB_LangSysRecord*  lsr;
+
+
+  base_offset = FILE_Pos();
+
+  if ( ACCESS_Frame( 2L ) )
+    return error;
+
+  new_offset = GET_UShort() + base_offset;
+
+  FORGET_Frame();
+
+  if ( new_offset != base_offset )        /* not a NULL offset */
+  {
+    cur_offset = FILE_Pos();
+    if ( FILE_Seek( new_offset ) ||
+	 ( error = Load_LangSys( &s->DefaultLangSys,
+				 stream ) ) != HB_Err_Ok )
+      return error;
+    (void)FILE_Seek( cur_offset );
+  }
+  else
+  {
+    /* we create a DefaultLangSys table with no entries */
+
+    s->DefaultLangSys.LookupOrderOffset = 0;
+    s->DefaultLangSys.ReqFeatureIndex   = 0xFFFF;
+    s->DefaultLangSys.FeatureCount      = 0;
+    s->DefaultLangSys.FeatureIndex      = NULL;
+  }
+
+  if ( ACCESS_Frame( 2L ) )
+    goto Fail2;
+
+  count = s->LangSysCount = GET_UShort();
+
+  /* safety check; otherwise the official handling of TrueType Open
+     fonts won't work */
+
+  if ( s->LangSysCount == 0 && s->DefaultLangSys.FeatureCount == 0 )
+  {
+    error = HB_Err_Not_Covered;
+    goto Fail2;
+  }
+
+  FORGET_Frame();
+
+  s->LangSysRecord = NULL;
+
+  if ( ALLOC_ARRAY( s->LangSysRecord, count, HB_LangSysRecord ) )
+    goto Fail2;
+
+  lsr = s->LangSysRecord;
+
+  for ( n = 0; n < count; n++ )
+  {
+    if ( ACCESS_Frame( 6L ) )
+      goto Fail1;
+
+    lsr[n].LangSysTag = GET_ULong();
+    new_offset = GET_UShort() + base_offset;
+
+    FORGET_Frame();
+
+    cur_offset = FILE_Pos();
+    if ( FILE_Seek( new_offset ) ||
+	 ( error = Load_LangSys( &lsr[n].LangSys, stream ) ) != HB_Err_Ok )
+      goto Fail1;
+    (void)FILE_Seek( cur_offset );
+  }
+
+  return HB_Err_Ok;
+
+Fail1:
+  for ( m = 0; m < n; m++ )
+    Free_LangSys( &lsr[m].LangSys );
+
+  FREE( s->LangSysRecord );
+
+Fail2:
+  Free_LangSys( &s->DefaultLangSys );
+  return error;
+}
+
+
+static void  Free_Script( HB_ScriptTable*  s )
+{
+  HB_UShort           n, count;
+
+  HB_LangSysRecord*  lsr;
+
+
+  Free_LangSys( &s->DefaultLangSys );
+
+  if ( s->LangSysRecord )
+  {
+    count = s->LangSysCount;
+    lsr   = s->LangSysRecord;
+
+    for ( n = 0; n < count; n++ )
+      Free_LangSys( &lsr[n].LangSys );
+
+    FREE( lsr );
+  }
+}
+
+
+/* ScriptList */
+
+HB_INTERNAL HB_Error
+_HB_OPEN_Load_ScriptList( HB_ScriptList* sl,
+			   HB_Stream        stream )
+{
+  HB_Error   error;
+
+  HB_UShort          n, script_count;
+  HB_UInt           cur_offset, new_offset, base_offset;
+
+  HB_ScriptRecord*  sr;
+
+
+  base_offset = FILE_Pos();
+
+  if ( ACCESS_Frame( 2L ) )
+    return error;
+
+  script_count = GET_UShort();
+
+  FORGET_Frame();
+
+  sl->ScriptRecord = NULL;
+
+  if ( ALLOC_ARRAY( sl->ScriptRecord, script_count, HB_ScriptRecord ) )
+    return error;
+
+  sr = sl->ScriptRecord;
+
+  sl->ScriptCount= 0;
+  for ( n = 0; n < script_count; n++ )
+  {
+    if ( ACCESS_Frame( 6L ) )
+      goto Fail;
+
+    sr[sl->ScriptCount].ScriptTag = GET_ULong();
+    new_offset = GET_UShort() + base_offset;
+
+    FORGET_Frame();
+
+    cur_offset = FILE_Pos();
+
+    if ( FILE_Seek( new_offset ) )
+      goto Fail;
+
+    error = Load_Script( &sr[sl->ScriptCount].Script, stream );
+    if ( error == HB_Err_Ok )
+      sl->ScriptCount += 1;
+    else if ( error != HB_Err_Not_Covered )
+      goto Fail;
+
+    (void)FILE_Seek( cur_offset );
+  }
+
+  /* Empty tables are harmless and generated by fontforge.
+   * See http://bugzilla.gnome.org/show_bug.cgi?id=347073
+   */
+#if 0
+  if ( sl->ScriptCount == 0 )
+  {
+    error = ERR(HB_Err_Invalid_SubTable);
+    goto Fail;
+  }
+#endif
+  
+  return HB_Err_Ok;
+
+Fail:
+  for ( n = 0; n < sl->ScriptCount; n++ )
+    Free_Script( &sr[n].Script );
+
+  FREE( sl->ScriptRecord );
+  return error;
+}
+
+
+HB_INTERNAL void
+_HB_OPEN_Free_ScriptList( HB_ScriptList* sl )
+{
+  HB_UShort          n, count;
+
+  HB_ScriptRecord*  sr;
+
+
+  if ( sl->ScriptRecord )
+  {
+    count = sl->ScriptCount;
+    sr    = sl->ScriptRecord;
+
+    for ( n = 0; n < count; n++ )
+      Free_Script( &sr[n].Script );
+
+    FREE( sr );
+  }
+}
+
+
+
+/*********************************
+ * Feature List related functions
+ *********************************/
+
+
+/* Feature */
+
+static HB_Error  Load_Feature( HB_Feature*  f,
+			       HB_Stream     stream )
+{
+  HB_Error   error;
+
+  HB_UShort   n, count;
+
+  HB_UShort*  lli;
+
+
+  if ( ACCESS_Frame( 4L ) )
+    return error;
+
+  f->FeatureParams           = GET_UShort();    /* should be 0 */
+  count = f->LookupListCount = GET_UShort();
+
+  FORGET_Frame();
+
+  f->LookupListIndex = NULL;
+
+  if ( ALLOC_ARRAY( f->LookupListIndex, count, HB_UShort ) )
+    return error;
+
+  lli = f->LookupListIndex;
+
+  if ( ACCESS_Frame( count * 2L ) )
+  {
+    FREE( f->LookupListIndex );
+    return error;
+  }
+
+  for ( n = 0; n < count; n++ )
+    lli[n] = GET_UShort();
+
+  FORGET_Frame();
+
+  return HB_Err_Ok;
+}
+
+
+static void  Free_Feature( HB_Feature*  f )
+{
+  FREE( f->LookupListIndex );
+}
+
+
+/* FeatureList */
+
+HB_INTERNAL HB_Error
+_HB_OPEN_Load_FeatureList( HB_FeatureList* fl,
+			    HB_Stream         stream )
+{
+  HB_Error   error;
+
+  HB_UShort           n, m, count;
+  HB_UInt            cur_offset, new_offset, base_offset;
+
+  HB_FeatureRecord*  fr;
+
+
+  base_offset = FILE_Pos();
+
+  if ( ACCESS_Frame( 2L ) )
+    return error;
+
+  count = fl->FeatureCount = GET_UShort();
+
+  FORGET_Frame();
+
+  fl->FeatureRecord = NULL;
+
+  if ( ALLOC_ARRAY( fl->FeatureRecord, count, HB_FeatureRecord ) )
+    return error;
+  if ( ALLOC_ARRAY( fl->ApplyOrder, count, HB_UShort ) )
+    goto Fail2;
+  
+  fl->ApplyCount = 0;
+
+  fr = fl->FeatureRecord;
+
+  for ( n = 0; n < count; n++ )
+  {
+    if ( ACCESS_Frame( 6L ) )
+      goto Fail1;
+
+    fr[n].FeatureTag = GET_ULong();
+    new_offset = GET_UShort() + base_offset;
+
+    FORGET_Frame();
+
+    cur_offset = FILE_Pos();
+    if ( FILE_Seek( new_offset ) ||
+	 ( error = Load_Feature( &fr[n].Feature, stream ) ) != HB_Err_Ok )
+      goto Fail1;
+    (void)FILE_Seek( cur_offset );
+  }
+
+  return HB_Err_Ok;
+
+Fail1:
+  for ( m = 0; m < n; m++ )
+    Free_Feature( &fr[m].Feature );
+
+  FREE( fl->ApplyOrder );
+
+Fail2:
+  FREE( fl->FeatureRecord );
+
+  return error;
+}
+
+
+HB_INTERNAL void
+_HB_OPEN_Free_FeatureList( HB_FeatureList*  fl )
+{
+  HB_UShort           n, count;
+
+  HB_FeatureRecord*  fr;
+
+
+  if ( fl->FeatureRecord )
+  {
+    count = fl->FeatureCount;
+    fr    = fl->FeatureRecord;
+
+    for ( n = 0; n < count; n++ )
+      Free_Feature( &fr[n].Feature );
+
+    FREE( fr );
+  }
+  
+  FREE( fl->ApplyOrder );
+}
+
+
+
+/********************************
+ * Lookup List related functions
+ ********************************/
+
+/* the subroutines of the following two functions are defined in
+   ftxgsub.c and ftxgpos.c respectively                          */
+
+
+/* SubTable */
+
+static HB_Error  Load_SubTable( HB_SubTable*  st,
+				HB_Stream     stream,
+				HB_Type       table_type,
+				HB_UShort     lookup_type )
+{
+  if ( table_type == HB_Type_GSUB )
+    return _HB_GSUB_Load_SubTable ( &st->st.gsub, stream, lookup_type );
+  else
+    return _HB_GPOS_Load_SubTable ( &st->st.gpos, stream, lookup_type );
+}
+
+
+static void  Free_SubTable( HB_SubTable*  st,
+			    HB_Type       table_type,
+			    HB_UShort      lookup_type )
+{
+  if ( table_type == HB_Type_GSUB )
+    _HB_GSUB_Free_SubTable ( &st->st.gsub, lookup_type );
+  else
+    _HB_GPOS_Free_SubTable ( &st->st.gpos, lookup_type );
+}
+
+
+/* Lookup */
+
+static HB_Error  Load_Lookup( HB_Lookup*   l,
+			      HB_Stream     stream,
+			      HB_Type      type )
+{
+  HB_Error   error;
+
+  HB_UShort      n, m, count;
+  HB_UInt       cur_offset, new_offset, base_offset;
+
+  HB_SubTable*  st;
+
+  HB_Bool        is_extension = FALSE;
+
+
+  base_offset = FILE_Pos();
+
+  if ( ACCESS_Frame( 6L ) )
+    return error;
+
+  l->LookupType            = GET_UShort();
+  l->LookupFlag            = GET_UShort();
+  count = l->SubTableCount = GET_UShort();
+
+  FORGET_Frame();
+
+  l->SubTable = NULL;
+
+  if ( ALLOC_ARRAY( l->SubTable, count, HB_SubTable ) )
+    return error;
+
+  st = l->SubTable;
+
+  if ( ( type == HB_Type_GSUB && l->LookupType == HB_GSUB_LOOKUP_EXTENSION ) ||
+       ( type == HB_Type_GPOS && l->LookupType == HB_GPOS_LOOKUP_EXTENSION ) )
+    is_extension = TRUE;
+
+  for ( n = 0; n < count; n++ )
+  {
+    if ( ACCESS_Frame( 2L ) )
+      goto Fail;
+
+    new_offset = GET_UShort() + base_offset;
+
+    FORGET_Frame();
+
+    cur_offset = FILE_Pos();
+
+    if ( is_extension )
+    {
+      if ( FILE_Seek( new_offset ) || ACCESS_Frame( 8L ) )
+	goto Fail;
+
+      if (GET_UShort() != 1) /* format should be 1 */
+	goto Fail;
+
+      l->LookupType = GET_UShort();
+      new_offset += GET_ULong();
+
+      FORGET_Frame();
+    }
+
+    if ( FILE_Seek( new_offset ) ||
+	 ( error = Load_SubTable( &st[n], stream,
+				  type, l->LookupType ) ) != HB_Err_Ok )
+      goto Fail;
+    (void)FILE_Seek( cur_offset );
+  }
+
+  return HB_Err_Ok;
+
+Fail:
+  for ( m = 0; m < n; m++ )
+    Free_SubTable( &st[m], type, l->LookupType );
+
+  FREE( l->SubTable );
+  return error;
+}
+
+
+static void  Free_Lookup( HB_Lookup*   l,
+			  HB_Type      type)
+{
+  HB_UShort      n, count;
+
+  HB_SubTable*  st;
+
+
+  if ( l->SubTable )
+  {
+    count = l->SubTableCount;
+    st    = l->SubTable;
+
+    for ( n = 0; n < count; n++ )
+      Free_SubTable( &st[n], type, l->LookupType );
+
+    FREE( st );
+  }
+}
+
+
+/* LookupList */
+
+HB_INTERNAL HB_Error
+_HB_OPEN_Load_LookupList( HB_LookupList* ll,
+			   HB_Stream        stream,
+			   HB_Type         type )
+{
+  HB_Error   error;
+
+  HB_UShort    n, m, count;
+  HB_UInt     cur_offset, new_offset, base_offset;
+
+  HB_Lookup*  l;
+
+
+  base_offset = FILE_Pos();
+
+  if ( ACCESS_Frame( 2L ) )
+    return error;
+
+  count = ll->LookupCount = GET_UShort();
+
+  FORGET_Frame();
+
+  ll->Lookup = NULL;
+
+  if ( ALLOC_ARRAY( ll->Lookup, count, HB_Lookup ) )
+    return error;
+  if ( ALLOC_ARRAY( ll->Properties, count, HB_UInt ) )
+    goto Fail2;
+
+  l = ll->Lookup;
+
+  for ( n = 0; n < count; n++ )
+  {
+    if ( ACCESS_Frame( 2L ) )
+      goto Fail1;
+
+    new_offset = GET_UShort() + base_offset;
+
+    FORGET_Frame();
+
+    cur_offset = FILE_Pos();
+    if ( FILE_Seek( new_offset ) ||
+	 ( error = Load_Lookup( &l[n], stream, type ) ) != HB_Err_Ok )
+      goto Fail1;
+    (void)FILE_Seek( cur_offset );
+  }
+
+  return HB_Err_Ok;
+
+Fail1:
+  FREE( ll->Properties );
+
+  for ( m = 0; m < n; m++ )
+    Free_Lookup( &l[m], type );
+
+Fail2:
+  FREE( ll->Lookup );
+  return error;
+}
+
+
+HB_INTERNAL void
+_HB_OPEN_Free_LookupList( HB_LookupList* ll,
+		       HB_Type         type )
+{
+  HB_UShort    n, count;
+
+  HB_Lookup*  l;
+
+
+  FREE( ll->Properties );
+
+  if ( ll->Lookup )
+  {
+    count = ll->LookupCount;
+    l     = ll->Lookup;
+
+    for ( n = 0; n < count; n++ )
+      Free_Lookup( &l[n], type );
+
+    FREE( l );
+  }
+}
+
+
+
+/*****************************
+ * Coverage related functions
+ *****************************/
+
+
+/* CoverageFormat1 */
+
+static HB_Error  Load_Coverage1( HB_CoverageFormat1*  cf1,
+				 HB_Stream             stream )
+{
+  HB_Error   error;
+
+  HB_UShort  n, count;
+
+  HB_UShort* ga;
+
+
+  if ( ACCESS_Frame( 2L ) )
+    return error;
+
+  count = cf1->GlyphCount = GET_UShort();
+
+  FORGET_Frame();
+
+  cf1->GlyphArray = NULL;
+
+  if ( ALLOC_ARRAY( cf1->GlyphArray, count, HB_UShort ) )
+    return error;
+
+  ga = cf1->GlyphArray;
+
+  if ( ACCESS_Frame( count * 2L ) )
+  {
+    FREE( cf1->GlyphArray );
+    return error;
+  }
+
+  for ( n = 0; n < count; n++ )
+    ga[n] = GET_UShort();
+
+  FORGET_Frame();
+
+  return HB_Err_Ok;
+}
+
+
+static void  Free_Coverage1( HB_CoverageFormat1*  cf1)
+{
+  FREE( cf1->GlyphArray );
+}
+
+
+/* CoverageFormat2 */
+
+static HB_Error  Load_Coverage2( HB_CoverageFormat2*  cf2,
+				 HB_Stream             stream )
+{
+  HB_Error   error;
+
+  HB_UShort         n, count;
+
+  HB_RangeRecord*  rr;
+
+
+  if ( ACCESS_Frame( 2L ) )
+    return error;
+
+  count = cf2->RangeCount = GET_UShort();
+
+  FORGET_Frame();
+
+  cf2->RangeRecord = NULL;
+
+  if ( ALLOC_ARRAY( cf2->RangeRecord, count, HB_RangeRecord ) )
+    return error;
+
+  rr = cf2->RangeRecord;
+
+  if ( ACCESS_Frame( count * 6L ) )
+    goto Fail;
+
+  for ( n = 0; n < count; n++ )
+  {
+    rr[n].Start              = GET_UShort();
+    rr[n].End                = GET_UShort();
+    rr[n].StartCoverageIndex = GET_UShort();
+
+    /* sanity check; we are limited to 16bit integers */
+    if ( rr[n].Start > rr[n].End ||
+	 ( rr[n].End - rr[n].Start + (long)rr[n].StartCoverageIndex ) >=
+	   0x10000L )
+    {
+      error = ERR(HB_Err_Invalid_SubTable);
+      goto Fail;
+    }
+  }
+
+  FORGET_Frame();
+
+  return HB_Err_Ok;
+
+Fail:
+  FREE( cf2->RangeRecord );
+  return error;
+}
+
+
+static void  Free_Coverage2( HB_CoverageFormat2*  cf2 )
+{
+  FREE( cf2->RangeRecord );
+}
+
+
+HB_INTERNAL HB_Error
+_HB_OPEN_Load_Coverage( HB_Coverage* c,
+			 HB_Stream      stream )
+{
+  HB_Error   error;
+
+  if ( ACCESS_Frame( 2L ) )
+    return error;
+
+  c->CoverageFormat = GET_UShort();
+
+  FORGET_Frame();
+
+  switch ( c->CoverageFormat )
+  {
+  case 1:  return Load_Coverage1( &c->cf.cf1, stream );
+  case 2:  return Load_Coverage2( &c->cf.cf2, stream );
+  default: return ERR(HB_Err_Invalid_SubTable_Format);
+  }
+
+  return HB_Err_Ok;               /* never reached */
+}
+
+
+HB_INTERNAL void
+_HB_OPEN_Free_Coverage( HB_Coverage* c )
+{
+  switch ( c->CoverageFormat )
+  {
+  case 1:  Free_Coverage1( &c->cf.cf1 ); break;
+  case 2:  Free_Coverage2( &c->cf.cf2 ); break;
+  default:					 break;
+  }
+}
+
+
+static HB_Error  Coverage_Index1( HB_CoverageFormat1*  cf1,
+				  HB_UShort             glyphID,
+				  HB_UShort*            index )
+{
+  HB_UShort min, max, new_min, new_max, middle;
+
+  HB_UShort*  array = cf1->GlyphArray;
+
+
+  /* binary search */
+
+  if ( cf1->GlyphCount == 0 )
+    return HB_Err_Not_Covered;
+
+  new_min = 0;
+  new_max = cf1->GlyphCount - 1;
+
+  do
+  {
+    min = new_min;
+    max = new_max;
+
+    /* we use (min + max) / 2 = max - (max - min) / 2  to avoid
+       overflow and rounding errors                             */
+
+    middle = max - ( ( max - min ) >> 1 );
+
+    if ( glyphID == array[middle] )
+    {
+      *index = middle;
+      return HB_Err_Ok;
+    }
+    else if ( glyphID < array[middle] )
+    {
+      if ( middle == min )
+	break;
+      new_max = middle - 1;
+    }
+    else
+    {
+      if ( middle == max )
+	break;
+      new_min = middle + 1;
+    }
+  } while ( min < max );
+
+  return HB_Err_Not_Covered;
+}
+
+
+static HB_Error  Coverage_Index2( HB_CoverageFormat2*  cf2,
+				  HB_UShort             glyphID,
+				  HB_UShort*            index )
+{
+  HB_UShort         min, max, new_min, new_max, middle;
+
+  HB_RangeRecord*  rr = cf2->RangeRecord;
+
+
+  /* binary search */
+
+  if ( cf2->RangeCount == 0 )
+    return HB_Err_Not_Covered;
+
+  new_min = 0;
+  new_max = cf2->RangeCount - 1;
+
+  do
+  {
+    min = new_min;
+    max = new_max;
+
+    /* we use (min + max) / 2 = max - (max - min) / 2  to avoid
+       overflow and rounding errors                             */
+
+    middle = max - ( ( max - min ) >> 1 );
+
+    if ( glyphID >= rr[middle].Start && glyphID <= rr[middle].End )
+    {
+      *index = rr[middle].StartCoverageIndex + glyphID - rr[middle].Start;
+      return HB_Err_Ok;
+    }
+    else if ( glyphID < rr[middle].Start )
+    {
+      if ( middle == min )
+	break;
+      new_max = middle - 1;
+    }
+    else
+    {
+      if ( middle == max )
+	break;
+      new_min = middle + 1;
+    }
+  } while ( min < max );
+
+  return HB_Err_Not_Covered;
+}
+
+
+HB_INTERNAL HB_Error
+_HB_OPEN_Coverage_Index( HB_Coverage* c,
+			  HB_UShort      glyphID,
+			  HB_UShort*     index )
+{
+  switch ( c->CoverageFormat )
+  {
+  case 1:  return Coverage_Index1( &c->cf.cf1, glyphID, index );
+  case 2:  return Coverage_Index2( &c->cf.cf2, glyphID, index );
+  default: return ERR(HB_Err_Invalid_SubTable_Format);
+  }
+
+  return HB_Err_Ok;               /* never reached */
+}
+
+
+
+/*************************************
+ * Class Definition related functions
+ *************************************/
+
+
+/* ClassDefFormat1 */
+
+static HB_Error  Load_ClassDef1( HB_ClassDefinition*  cd,
+				 HB_UShort             limit,
+				 HB_Stream             stream )
+{
+  HB_Error   error;
+
+  HB_UShort             n, count;
+
+  HB_UShort*            cva;
+
+  HB_ClassDefFormat1*  cdf1;
+
+
+  cdf1 = &cd->cd.cd1;
+
+  if ( ACCESS_Frame( 4L ) )
+    return error;
+
+  cdf1->StartGlyph         = GET_UShort();
+  count = cdf1->GlyphCount = GET_UShort();
+
+  FORGET_Frame();
+
+  /* sanity check; we are limited to 16bit integers */
+
+  if ( cdf1->StartGlyph + (long)count >= 0x10000L )
+    return ERR(HB_Err_Invalid_SubTable);
+
+  cdf1->ClassValueArray = NULL;
+
+  if ( ALLOC_ARRAY( cdf1->ClassValueArray, count, HB_UShort ) )
+    return error;
+
+  cva = cdf1->ClassValueArray;
+
+  if ( ACCESS_Frame( count * 2L ) )
+    goto Fail;
+
+  for ( n = 0; n < count; n++ )
+  {
+    cva[n] = GET_UShort();
+    if ( cva[n] >= limit )
+    {
+      error = ERR(HB_Err_Invalid_SubTable);
+      goto Fail;
+    }
+  }
+
+  FORGET_Frame();
+
+  return HB_Err_Ok;
+
+Fail:
+  FREE( cva );
+
+  return error;
+}
+
+
+static void  Free_ClassDef1( HB_ClassDefFormat1*  cdf1 )
+{
+  FREE( cdf1->ClassValueArray );
+}
+
+
+/* ClassDefFormat2 */
+
+static HB_Error  Load_ClassDef2( HB_ClassDefinition*  cd,
+				 HB_UShort             limit,
+				 HB_Stream             stream )
+{
+  HB_Error   error;
+
+  HB_UShort              n, count;
+
+  HB_ClassRangeRecord*  crr;
+
+  HB_ClassDefFormat2*   cdf2;
+
+
+  cdf2 = &cd->cd.cd2;
+
+  if ( ACCESS_Frame( 2L ) )
+    return error;
+
+  count = GET_UShort();
+  cdf2->ClassRangeCount = 0; /* zero for now.  we fill with the number of good entries later */
+
+  FORGET_Frame();
+
+  cdf2->ClassRangeRecord = NULL;
+
+  if ( ALLOC_ARRAY( cdf2->ClassRangeRecord, count, HB_ClassRangeRecord ) )
+    return error;
+
+  crr = cdf2->ClassRangeRecord;
+
+  if ( ACCESS_Frame( count * 6L ) )
+    goto Fail;
+
+  for ( n = 0; n < count; n++ )
+  {
+    crr[n].Start = GET_UShort();
+    crr[n].End   = GET_UShort();
+    crr[n].Class = GET_UShort();
+
+    /* sanity check */
+
+    if ( crr[n].Start > crr[n].End ||
+	 crr[n].Class >= limit )
+    {
+      /* XXX
+       * Corrupt entry.  Skip it.
+       * This is hit by Nafees Nastaliq font for example
+       */
+       n--;
+       count--;
+    }
+  }
+
+  FORGET_Frame();
+
+  cdf2->ClassRangeCount = count;
+
+  return HB_Err_Ok;
+
+Fail:
+  FREE( crr );
+
+  return error;
+}
+
+
+static void  Free_ClassDef2( HB_ClassDefFormat2*  cdf2 )
+{
+  FREE( cdf2->ClassRangeRecord );
+}
+
+
+/* ClassDefinition */
+
+HB_INTERNAL HB_Error
+_HB_OPEN_Load_ClassDefinition( HB_ClassDefinition* cd,
+				HB_UShort             limit,
+				HB_Stream             stream )
+{
+  HB_Error   error;
+
+  if ( ACCESS_Frame( 2L ) )
+    return error;
+
+  cd->ClassFormat = GET_UShort();
+
+  FORGET_Frame();
+
+  switch ( cd->ClassFormat )
+  {
+  case 1:  error = Load_ClassDef1( cd, limit, stream ); break;
+  case 2:  error = Load_ClassDef2( cd, limit, stream ); break;
+  default: error = ERR(HB_Err_Invalid_SubTable_Format);	break;
+  }
+
+  if ( error )
+    return error;
+
+  cd->loaded = TRUE;
+
+  return HB_Err_Ok;
+}
+
+
+static HB_Error
+_HB_OPEN_Load_EmptyClassDefinition( HB_ClassDefinition*  cd )
+{
+  HB_Error   error;
+
+  cd->ClassFormat = 1; /* Meaningless */
+
+  if ( ALLOC_ARRAY( cd->cd.cd1.ClassValueArray, 1, HB_UShort ) )
+    return error;
+
+  return HB_Err_Ok;
+}
+
+HB_INTERNAL HB_Error
+_HB_OPEN_Load_EmptyOrClassDefinition( HB_ClassDefinition* cd,
+					       HB_UShort             limit,
+					       HB_UInt              class_offset,
+					       HB_UInt              base_offset,
+					       HB_Stream             stream )
+{
+  HB_Error error;
+  HB_UInt               cur_offset;
+
+  cur_offset = FILE_Pos();
+
+  if ( class_offset )
+    {
+      if ( !FILE_Seek( class_offset + base_offset ) )
+	error = _HB_OPEN_Load_ClassDefinition( cd, limit, stream );
+    }
+  else
+     error = _HB_OPEN_Load_EmptyClassDefinition ( cd );
+
+  if (error == HB_Err_Ok)
+    (void)FILE_Seek( cur_offset ); /* Changes error as a side-effect */
+
+  return error;
+}
+
+HB_INTERNAL void
+_HB_OPEN_Free_ClassDefinition( HB_ClassDefinition*  cd )
+{
+  if ( !cd->loaded )
+    return;
+
+  switch ( cd->ClassFormat )
+  {
+  case 1:  Free_ClassDef1( &cd->cd.cd1 ); break;
+  case 2:  Free_ClassDef2( &cd->cd.cd2 ); break;
+  default:				  break;
+  }
+}
+
+
+static HB_Error  Get_Class1( HB_ClassDefFormat1*  cdf1,
+			     HB_UShort             glyphID,
+			     HB_UShort*            klass,
+			     HB_UShort*            index )
+{
+  HB_UShort*  cva = cdf1->ClassValueArray;
+
+
+  if ( index )
+    *index = 0;
+
+  if ( glyphID >= cdf1->StartGlyph &&
+       glyphID < cdf1->StartGlyph + cdf1->GlyphCount )
+  {
+    *klass = cva[glyphID - cdf1->StartGlyph];
+    return HB_Err_Ok;
+  }
+  else
+  {
+    *klass = 0;
+    return HB_Err_Not_Covered;
+  }
+}
+
+
+/* we need the index value of the last searched class range record
+   in case of failure for constructed GDEF tables                  */
+
+static HB_Error  Get_Class2( HB_ClassDefFormat2*  cdf2,
+			     HB_UShort             glyphID,
+			     HB_UShort*            klass,
+			     HB_UShort*            index )
+{
+  HB_Error               error = HB_Err_Ok;
+  HB_UShort              min, max, new_min, new_max, middle;
+
+  HB_ClassRangeRecord*  crr = cdf2->ClassRangeRecord;
+
+
+  /* binary search */
+
+  if ( cdf2->ClassRangeCount == 0 )
+    {
+      *klass = 0;
+      if ( index )
+	*index = 0;
+      
+      return HB_Err_Not_Covered;
+    }
+
+  new_min = 0;
+  new_max = cdf2->ClassRangeCount - 1;
+
+  do
+  {
+    min = new_min;
+    max = new_max;
+
+    /* we use (min + max) / 2 = max - (max - min) / 2  to avoid
+       overflow and rounding errors                             */
+
+    middle = max - ( ( max - min ) >> 1 );
+
+    if ( glyphID >= crr[middle].Start && glyphID <= crr[middle].End )
+    {
+      *klass = crr[middle].Class;
+      error  = HB_Err_Ok;
+      break;
+    }
+    else if ( glyphID < crr[middle].Start )
+    {
+      if ( middle == min )
+      {
+	*klass = 0;
+	error  = HB_Err_Not_Covered;
+	break;
+      }
+      new_max = middle - 1;
+    }
+    else
+    {
+      if ( middle == max )
+      {
+	*klass = 0;
+	error  = HB_Err_Not_Covered;
+	break;
+      }
+      new_min = middle + 1;
+    }
+  } while ( min < max );
+
+  if ( index )
+    *index = middle;
+
+  return error;
+}
+
+
+HB_INTERNAL HB_Error
+_HB_OPEN_Get_Class( HB_ClassDefinition* cd,
+		     HB_UShort             glyphID,
+		    HB_UShort*          klass,
+		     HB_UShort*            index )
+{
+  switch ( cd->ClassFormat )
+  {
+  case 1:  return Get_Class1( &cd->cd.cd1, glyphID, klass, index );
+  case 2:  return Get_Class2( &cd->cd.cd2, glyphID, klass, index );
+  default: return ERR(HB_Err_Invalid_SubTable_Format);
+  }
+
+  return HB_Err_Ok;               /* never reached */
+}
+
+
+
+/***************************
+ * Device related functions
+ ***************************/
+
+
+HB_INTERNAL HB_Error
+_HB_OPEN_Load_Device( HB_Device* d,
+		       HB_Stream    stream )
+{
+  HB_Error   error;
+
+  HB_UShort   n, count;
+
+  HB_UShort*  dv;
+
+
+  if ( ACCESS_Frame( 6L ) )
+    return error;
+
+  d->StartSize   = GET_UShort();
+  d->EndSize     = GET_UShort();
+  d->DeltaFormat = GET_UShort();
+
+  FORGET_Frame();
+
+  d->DeltaValue = NULL;
+
+  if ( d->StartSize > d->EndSize ||
+       d->DeltaFormat == 0 || d->DeltaFormat > 3 )
+    {
+      /* XXX
+       * I've seen fontforge generate DeltaFormat == 0.
+       * Just return Ok and let the NULL DeltaValue disable
+       * this table.
+       */
+      return HB_Err_Ok;
+    }
+
+  count = ( ( d->EndSize - d->StartSize + 1 ) >>
+	      ( 4 - d->DeltaFormat ) ) + 1;
+
+  if ( ALLOC_ARRAY( d->DeltaValue, count, HB_UShort ) )
+    return error;
+
+  if ( ACCESS_Frame( count * 2L ) )
+  {
+    FREE( d->DeltaValue );
+    return error;
+  }
+
+  dv = d->DeltaValue;
+
+  for ( n = 0; n < count; n++ )
+    dv[n] = GET_UShort();
+
+  FORGET_Frame();
+
+  return HB_Err_Ok;
+}
+
+
+HB_INTERNAL void
+_HB_OPEN_Free_Device( HB_Device* d )
+{
+  FREE( d->DeltaValue );
+}
+
+
+/* Since we have the delta values stored in compressed form, we must
+   uncompress it now.  To simplify the interface, the function always
+   returns a meaningful value in `value'; the error is just for
+   information.
+			       |                |
+   format = 1: 0011223344556677|8899101112131415|...
+			       |                |
+		    byte 1           byte 2
+
+     00: (byte >> 14) & mask
+     11: (byte >> 12) & mask
+     ...
+
+     mask = 0x0003
+			       |                |
+   format = 2: 0000111122223333|4444555566667777|...
+			       |                |
+		    byte 1           byte 2
+
+     0000: (byte >> 12) & mask
+     1111: (byte >>  8) & mask
+     ...
+
+     mask = 0x000F
+			       |                |
+   format = 3: 0000000011111111|2222222233333333|...
+			       |                |
+		    byte 1           byte 2
+
+     00000000: (byte >> 8) & mask
+     11111111: (byte >> 0) & mask
+     ....
+
+     mask = 0x00FF                                    */
+
+HB_INTERNAL HB_Error
+_HB_OPEN_Get_Device( HB_Device* d,
+		      HB_UShort    size,
+		      HB_Short*    value )
+{
+  HB_UShort  byte, bits, mask, f, s;
+
+
+  f = d->DeltaFormat;
+
+  if ( d->DeltaValue && size >= d->StartSize && size <= d->EndSize )
+  {
+    s    = size - d->StartSize;
+    byte = d->DeltaValue[s >> ( 4 - f )];
+    bits = byte >> ( 16 - ( ( s % ( 1 << ( 4 - f ) ) + 1 ) << f ) );
+    mask = 0xFFFF >> ( 16 - ( 1 << f ) );
+
+    *value = (HB_Short)( bits & mask );
+
+    /* conversion to a signed value */
+
+    if ( *value >= ( ( mask + 1 ) >> 1 ) )
+      *value -= mask + 1;
+
+    return HB_Err_Ok;
+  }
+  else
+  {
+    *value = 0;
+    return HB_Err_Not_Covered;
+  }
+}
+
+
+/* END */