From 6f74f18b77402f3adf5bfbae26e8f44de6543b4e Mon Sep 17 00:00:00 2001
From: Owen Taylor <otaylor@redhat.com>
Date: Sat, 26 Jul 2003 03:03:40 +0000
Subject: [PATCH] Add GPOS_LOOKUP_EXTENSION, GSUB_LOOKUP_EXTENSION, which allow
 lookup

Fri Jul 25 22:59:13 2003  Owen Taylor  <otaylor@redhat.com>

        * pango/opentype/ftx{gpos,gsub}.h pango/opentype/ftxgdef.c:
        Add GPOS_LOOKUP_EXTENSION, GSUB_LOOKUP_EXTENSION, which
        allow lookup information to be stored at 32-bit offets
        via a double indirection. (From FreeType, Werner Lemberg,
        2001-08-08)
---
 src/ftxgpos.h | 17 +++++++++--------
 src/ftxgsub.h |  1 +
 src/ftxopen.c | 19 +++++++++++++++++++
 3 files changed, 29 insertions(+), 8 deletions(-)

diff --git a/src/ftxgpos.h b/src/ftxgpos.h
index 56ffb7852..408bcb0ae 100644
--- a/src/ftxgpos.h
+++ b/src/ftxgpos.h
@@ -32,14 +32,15 @@ extern "C" {
 
 /* Lookup types for glyph positioning */
 
-#define GPOS_LOOKUP_SINGLE    1
-#define GPOS_LOOKUP_PAIR      2
-#define GPOS_LOOKUP_CURSIVE   3
-#define GPOS_LOOKUP_MARKBASE  4
-#define GPOS_LOOKUP_MARKLIG   5
-#define GPOS_LOOKUP_MARKMARK  6
-#define GPOS_LOOKUP_CONTEXT   7
-#define GPOS_LOOKUP_CHAIN     8
+#define GPOS_LOOKUP_SINGLE     1
+#define GPOS_LOOKUP_PAIR       2
+#define GPOS_LOOKUP_CURSIVE    3
+#define GPOS_LOOKUP_MARKBASE   4
+#define GPOS_LOOKUP_MARKLIG    5
+#define GPOS_LOOKUP_MARKMARK   6
+#define GPOS_LOOKUP_CONTEXT    7
+#define GPOS_LOOKUP_CHAIN      8
+#define GPOS_LOOKUP_EXTENSION  9
 
 
   /* A pointer to a function which loads a glyph.  Its parameters are
diff --git a/src/ftxgsub.h b/src/ftxgsub.h
index 3f4f8adac..8951e4413 100644
--- a/src/ftxgsub.h
+++ b/src/ftxgsub.h
@@ -38,6 +38,7 @@ extern "C" {
 #define GSUB_LOOKUP_LIGATURE   4
 #define GSUB_LOOKUP_CONTEXT    5
 #define GSUB_LOOKUP_CHAIN      6
+#define GSUB_LOOKUP_EXTENSION  7
 
 
 /* Use this if a feature applies to all glyphs */
diff --git a/src/ftxopen.c b/src/ftxopen.c
index ba605bd74..5d9cfad31 100644
--- a/src/ftxopen.c
+++ b/src/ftxopen.c
@@ -584,6 +584,8 @@
 
     TTO_SubTable*  st;
 
+    Bool           is_extension = FALSE;
+
 
     base_offset = FILE_Pos();
 
@@ -603,6 +605,10 @@
 
     st = l->SubTable;
 
+    if ( ( type == GSUB && l->LookupType == GSUB_LOOKUP_EXTENSION ) ||
+         ( type == GPOS && l->LookupType == GPOS_LOOKUP_EXTENSION ) )
+      is_extension = TRUE;
+
     for ( n = 0; n < count; n++ )
     {
       if ( ACCESS_Frame( 2L ) )
@@ -613,6 +619,19 @@
       FORGET_Frame();
 
       cur_offset = FILE_Pos();
+
+      if ( is_extension )
+      {
+        if ( FILE_Seek( new_offset ) || ACCESS_Frame( 8L ) )
+          goto Fail;
+
+        (void)GET_UShort();                     /* format should be 1 */
+        l->LookupType = GET_UShort();
+        new_offset = GET_ULong() + base_offset;
+
+        FORGET_Frame();
+      }
+
       if ( FILE_Seek( new_offset ) ||
            ( error = Load_SubTable( &st[n], stream,
                                     type, l->LookupType ) ) != TT_Err_Ok )