dwrite: Handle extension substitution (GSUB lookup 7).

Signed-off-by: Nikolay Sivov <nsivov@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>

dlls/dwrite/opentype.c

@@ -547,7 +547,7 @@ enum OPENTYPE_PLATFORM_ID
     OPENTYPE_PLATFORM_CUSTOM
 };
 
-struct ot_gsubgpos_extensionpos_format1
+struct ot_gsubgpos_extension_format1
 {
     UINT16 format;
     UINT16 lookup_type;
@@ -3385,7 +3385,7 @@ static unsigned int opentype_layout_get_gpos_subtable(const struct scriptshaping
             FIELD_OFFSET(struct ot_lookup_table, subtable[subtable]));
     if (lookup_type == GPOS_LOOKUP_EXTENSION_POSITION)
     {
-        const struct ot_gsubgpos_extensionpos_format1 *format1 = table_read_ensure(&cache->gpos.table,
+        const struct ot_gsubgpos_extension_format1 *format1 = table_read_ensure(&cache->gpos.table,
                 lookup_offset + subtable_offset, sizeof(*format1));
         subtable_offset += GET_BE_DWORD(format1->extension_offset);
     }
@@ -3393,18 +3393,11 @@ static unsigned int opentype_layout_get_gpos_subtable(const struct scriptshaping
     return lookup_offset + subtable_offset;
 }
 
-static unsigned int opentype_layout_get_gsub_subtable(const struct scriptshaping_cache *cache,
+static unsigned int opentype_layout_get_gsub_subtable(const struct scriptshaping_context *context,
         unsigned int lookup_offset, unsigned int subtable)
 {
-    UINT16 lookup_type = table_read_be_word(&cache->gsub.table, lookup_offset);
+    unsigned int subtable_offset = table_read_be_word(&context->table->table, lookup_offset +
-    unsigned int subtable_offset = table_read_be_word(&cache->gsub.table, lookup_offset +
             FIELD_OFFSET(struct ot_lookup_table, subtable[subtable]));
-    if (lookup_type == GSUB_LOOKUP_EXTENSION_SUBST)
-    {
-        const struct ot_gsubgpos_extensionpos_format1 *format1 = table_read_ensure(&cache->gsub.table,
-                lookup_offset + subtable_offset, sizeof(*format1));
-        subtable_offset += GET_BE_DWORD(format1->extension_offset);
-    }
 
     return lookup_offset + subtable_offset;
 }
@@ -4086,7 +4079,7 @@ static void opentype_layout_apply_gpos_lookup(struct scriptshaping_context *cont
     lookup_type = GET_BE_WORD(lookup_table->lookup_type);
     if (lookup_type == GPOS_LOOKUP_EXTENSION_POSITION)
     {
-        const struct ot_gsubgpos_extensionpos_format1 *extension = table_read_ensure(&cache->gpos.table,
+        const struct ot_gsubgpos_extension_format1 *extension = table_read_ensure(&cache->gpos.table,
                 lookup.offset + GET_BE_WORD(lookup_table->subtable[0]), sizeof(*extension));
         WORD format;
 
@@ -4462,22 +4455,17 @@ void opentype_layout_apply_gpos_features(struct scriptshaping_context *context,
     heap_free(lookups.lookups);
 }
 
-static BOOL opentype_layout_apply_gsub_single_substitution(struct scriptshaping_context *context, const struct lookup *lookup)
+static BOOL opentype_layout_apply_gsub_single_substitution(struct scriptshaping_context *context, const struct lookup *lookup,
+        unsigned int subtable_offset)
 {
-    struct scriptshaping_cache *cache = context->cache;
     const struct dwrite_fonttable *gsub = &context->table->table;
     UINT16 format, coverage, orig_glyph, glyph;
-    unsigned int i, idx;
+    unsigned int idx, coverage_index;
     BOOL ret;
 
     idx = context->cur;
     orig_glyph = glyph = context->u.subst.glyphs[idx];
 
-    for (i = 0; i < lookup->subtable_count; ++i)
-    {
-        unsigned int subtable_offset = opentype_layout_get_gsub_subtable(cache, lookup->offset, i);
-        unsigned int coverage_index;
-
     format = table_read_be_word(gsub, subtable_offset);
 
     coverage = table_read_be_word(gsub, subtable_offset + FIELD_OFFSET(struct ot_gsub_singlesubst_format1, coverage));
@@ -4488,10 +4476,9 @@ static BOOL opentype_layout_apply_gsub_single_substitution(struct scriptshaping_
 
         coverage_index = opentype_layout_is_glyph_covered(context, subtable_offset + coverage, glyph);
         if (coverage_index == GLYPH_NOT_COVERED)
-                continue;
+            return FALSE;
 
         glyph = orig_glyph + GET_BE_WORD(format1->delta);
-            break;
     }
     else if (format == 2)
     {
@@ -4501,14 +4488,12 @@ static BOOL opentype_layout_apply_gsub_single_substitution(struct scriptshaping_
 
         coverage_index = opentype_layout_is_glyph_covered(context, subtable_offset + coverage, glyph);
         if (coverage_index == GLYPH_NOT_COVERED || coverage_index >= count)
-                continue;
+            return FALSE;
 
         glyph = GET_BE_WORD(format2->substitutes[coverage_index]);
-            break;
     }
     else
         WARN("Unknown single substitution format %u.\n", format);
-    }
 
     if ((ret = (glyph != orig_glyph)))
     {
@@ -4684,21 +4669,16 @@ static BOOL opentype_layout_apply_gsub_chain_context_lookup(struct scriptshaping
 }
 
 static BOOL opentype_layout_apply_gsub_chain_context_substitution(struct scriptshaping_context *context,
-        const struct lookup *lookup)
+        const struct lookup *lookup, unsigned int subtable_offset)
 {
-    struct scriptshaping_cache *cache = context->cache;
     const struct dwrite_fonttable *table = &context->table->table;
-    UINT16 format, coverage;
-    BOOL ret = FALSE;
-    unsigned int i;
-
-    for (i = 0; i < lookup->subtable_count; ++i)
-    {
-        unsigned int subtable_offset = opentype_layout_get_gsub_subtable(cache, lookup->offset, i);
-        UINT16 glyph = context->u.subst.glyphs[context->cur];
     unsigned int coverage_index = GLYPH_NOT_COVERED;
+    UINT16 glyph, format, coverage;
+    BOOL ret = FALSE;
 
-        format = table_read_be_word(&context->table->table, subtable_offset);
+    glyph = context->u.subst.glyphs[context->cur];
+
+    format = table_read_be_word(table, subtable_offset);
 
     if (format == 1)
     {
@@ -4707,21 +4687,20 @@ static BOOL opentype_layout_apply_gsub_chain_context_substitution(struct scripts
 
         coverage_index = opentype_layout_is_glyph_covered(context, subtable_offset + coverage, glyph);
         if (coverage_index == GLYPH_NOT_COVERED)
-                continue;
+            return FALSE;
 
         WARN("Chaining contextual substitution (1) is not supported.\n");
-            break;
     }
     else if (format == 2)
     {
-            coverage = table_read_be_word(table, subtable_offset + FIELD_OFFSET(struct ot_gsub_chaincontext_subst_format1, coverage));
+        coverage = table_read_be_word(table, subtable_offset +
+                FIELD_OFFSET(struct ot_gsub_chaincontext_subst_format1, coverage));
 
         coverage_index = opentype_layout_is_glyph_covered(context, subtable_offset + coverage, glyph);
         if (coverage_index == GLYPH_NOT_COVERED)
-                continue;
+            return FALSE;
 
         WARN("Chaining contextual substitution (2) is not supported.\n");
-            break;
     }
     else if (format == 3)
     {
@@ -4753,32 +4732,61 @@ static BOOL opentype_layout_apply_gsub_chain_context_substitution(struct scripts
             coverage_index = opentype_layout_is_glyph_covered(context, subtable_offset + GET_BE_WORD(input[0]), glyph);
 
         if (coverage_index == GLYPH_NOT_COVERED)
-                continue;
+            return FALSE;
 
-            if ((ret = opentype_layout_apply_gsub_chain_context_lookup(context, subtable_offset, backtrack_count, backtrack,
+        ret = opentype_layout_apply_gsub_chain_context_lookup(context, subtable_offset, backtrack_count, backtrack,
-                input_count, input + 1, lookahead_count, lookahead, lookup_count, lookup_records)))
+                input_count, input + 1, lookahead_count, lookahead, lookup_count, lookup_records);
-            {
-                break;
-            }
     }
     else
         WARN("Unknown chaining contextual substitution format %u.\n", format);
-    }
 
     return ret;
 }
 
+static unsigned int opentype_layout_adjust_extension_subtable(struct scriptshaping_context *context,
+        unsigned int *subtable_offset)
+{
+    const struct ot_gsubgpos_extension_format1 *format1;
+
+    if (!(format1 = table_read_ensure(&context->table->table, *subtable_offset, sizeof(*format1))))
+        return 0;
+
+    if (GET_BE_WORD(format1->format) != 1)
+    {
+        WARN("Unexpected extension table format %#x.\n", format1->format);
+        return 0;
+    }
+
+    *subtable_offset = *subtable_offset + GET_BE_DWORD(format1->extension_offset);
+
+    return GET_BE_WORD(format1->lookup_type);
+}
+
 static BOOL opentype_layout_apply_gsub_lookup(struct scriptshaping_context *context, const struct lookup *lookup)
 {
+    unsigned int i, lookup_type;
     BOOL ret = FALSE;
 
-    switch (lookup->type)
+    for (i = 0; i < lookup->subtable_count; ++i)
+    {
+        unsigned int subtable_offset = opentype_layout_get_gsub_subtable(context, lookup->offset, i);
+
+        if (lookup->type == GSUB_LOOKUP_EXTENSION_SUBST)
+        {
+            lookup_type = opentype_layout_adjust_extension_subtable(context, &subtable_offset);
+            if (!lookup_type)
+                continue;
+        }
+        else
+            lookup_type = lookup->type;
+
+        switch (lookup_type)
         {
             case GSUB_LOOKUP_SINGLE_SUBST:
-            ret = opentype_layout_apply_gsub_single_substitution(context, lookup);
+                ret = opentype_layout_apply_gsub_single_substitution(context, lookup, subtable_offset);
                 break;
             case GSUB_LOOKUP_CHAINING_CONTEXTUAL_SUBST:
-            ret = opentype_layout_apply_gsub_chain_context_substitution(context, lookup);
+                ret = opentype_layout_apply_gsub_chain_context_substitution(context, lookup, subtable_offset);
                 break;
             case GSUB_LOOKUP_MULTIPLE_SUBST:
             case GSUB_LOOKUP_ALTERNATE_SUBST:
@@ -4787,8 +4795,15 @@ static BOOL opentype_layout_apply_gsub_lookup(struct scriptshaping_context *cont
             case GSUB_LOOKUP_REVERSE_CHAINING_CONTEXTUAL_SUBST:
                 WARN("Unimplemented lookup %d.\n", lookup->type);
                 break;
+            case GSUB_LOOKUP_EXTENSION_SUBST:
+                WARN("Invalid lookup type for extension substitution %#x.\n", lookup_type);
+                break;
             default:
-            WARN("Unknown lookup type %u.\n", lookup->type);
+                WARN("Unknown lookup type %u.\n", lookup_type);
+        }
+
+        if (ret)
+            break;
     }
 
     return ret;