[freetype2] gsoc-craig-2023 ed574779d: Fix infinite loop bug in tilde fix, added then commented out a bunch of non-working GSUB handling

[Werner Lemberg]

branch: gsoc-craig-2023
commit ed574779d7bbd8aa866a78ca96312ce6aaae1efb
Author: Craig White <gerzytet@gmail.com>
Commit: Craig White <gerzytet@gmail.com>

    Fix infinite loop bug in tilde fix, added then commented out a bunch of 
non-working GSUB handling
---
 src/autofit/afadjust.c | 48 +++++++++++++++++++++++++++++++++++++++---------
 src/autofit/aflatin.c  | 16 ++++++++++------
 2 files changed, 49 insertions(+), 15 deletions(-)

diff --git a/src/autofit/afadjust.c b/src/autofit/afadjust.c
index d1fea63cc..e7970f7d0 100644
--- a/src/autofit/afadjust.c
+++ b/src/autofit/afadjust.c
@@ -187,8 +187,17 @@ af_lookup_vertical_seperation_type( AF_ReverseCharacterMap 
map, FT_Int glyph_ind
 FT_LOCAL_DEF( FT_Int )
 af_lookup_tilde_correction_type( AF_ReverseCharacterMap map, FT_Int 
glyph_index ) {
     FT_UInt32 codepoint = af_reverse_character_map_lookup( map, glyph_index );
-    if ( codepoint == 0xF1 ) {
-        return 1;
+    /* bits are: apply stretch, apply segment removal */
+    if ( codepoint == 0xF1 ) { /*n tilde*/
+        return 0b01;
+    }
+    else if ( codepoint == 0xE3 ) /*a tilde*/
+    {
+        return 0b11;
+    }
+    else if ( codepoint == 0xF5 ) /*o tilde*/
+    {
+        return 0b10;
     }
     return 0;
 }
@@ -336,7 +345,8 @@ af_reverse_character_map_new( AF_ReverseCharacterMap *map, 
AF_FaceGlobals global
         af_reverse_character_map_entry_compare
     );
 
-#ifdef FT_CONFIG_OPTION_USE_HARFBUZZ
+#if 0
+/*#ifdef FT_CONFIG_OPTION_USE_HARFBUZZ*/
     hb_font_t *hb_font = globals->hb_font;
     hb_face_t *hb_face = hb_font_get_face( hb_font );
     hb_set_t  *feature_indicies = hb_set_create();
@@ -350,8 +360,6 @@ af_reverse_character_map_new( AF_ReverseCharacterMap *map, 
AF_FaceGlobals global
         feature_indicies
     );
     hb_codepoint_t feature_index = HB_SET_VALUE_INVALID;
-
-    FT_UInt added_entries = 0;
     while ( hb_set_next(feature_indicies, &feature_index) )
     {
         hb_codepoint_t output_glyph_index;
@@ -366,6 +374,20 @@ af_reverse_character_map_new( AF_ReverseCharacterMap *map, 
AF_FaceGlobals global
                                             glyphs_output);
         /*Don't consider anything involving context.  Just do the
           simple cases*/
+        FT_TRACE4(("num inputs: %d\n", hb_set_get_population( glyphs_input )));
+        FT_TRACE4(("num outputs: %d\n", hb_set_get_population( glyphs_output 
)));
+        FT_TRACE4(("num before: %d\n", hb_set_get_population( glyphs_before 
)));
+        FT_TRACE4(("num after: %d\n", hb_set_get_population( glyphs_after )));
+        hb_codepoint_t input = HB_SET_VALUE_INVALID;
+        while ( hb_set_next( glyphs_input, &input ) )
+        {
+            FT_TRACE4(("input: %d\n", input));
+        }
+        hb_codepoint_t output = HB_SET_VALUE_INVALID;
+        while ( hb_set_next( glyphs_output, &output ) )
+        {
+            FT_TRACE4(("output: %d\n", output));
+        }
         if ( hb_set_get_population( glyphs_before ) > 0 ||
              hb_set_get_population( glyphs_after ) > 0 )
         {
@@ -378,18 +400,22 @@ af_reverse_character_map_new( AF_ReverseCharacterMap 
*map, AF_FaceGlobals global
 
         hb_codepoint_t input_glyph_index = HB_SET_VALUE_INVALID;
         const AF_AdjustmentDatabaseEntry* input_entry = NULL;
-        FT_UInt32 input_codepoint;
+        FT_UInt32 input_codepoint = 0;
         while ( hb_set_next( glyphs_input, &input_glyph_index ) ) {
-            input_codepoint = af_reverse_character_map_lookup_( *map, 
input_glyph_index, oldlength );
-            if ( input_codepoint == 0 )
+            FT_TRACE4(("input glyph: %d\n", input_glyph_index));
+            FT_UInt32 inner_codepoint = af_reverse_character_map_lookup_( 
*map, input_glyph_index, oldlength );
+            if ( inner_codepoint == 0 )
             {
                 continue;
             }
-            const AF_AdjustmentDatabaseEntry* entry = 
af_adjustment_database_lookup( input_codepoint );
+            const AF_AdjustmentDatabaseEntry* entry = 
af_adjustment_database_lookup( inner_codepoint );
             if ( entry == NULL )
             {
                 continue;
             }
+            if ( input_codepoint == 0 ) {
+                input_codepoint = inner_codepoint;
+            }
 
             if ( input_entry == NULL )
             {
@@ -404,6 +430,10 @@ af_reverse_character_map_new( AF_ReverseCharacterMap *map, 
AF_FaceGlobals global
             }
         }
 
+        if ( input_codepoint == 0 )
+        {
+            continue;
+        }
 
         output_glyph_index = HB_SET_VALUE_INVALID;
         hb_set_next( glyphs_output, &output_glyph_index );
diff --git a/src/autofit/aflatin.c b/src/autofit/aflatin.c
index a88ec6cc0..dfad4a191 100644
--- a/src/autofit/aflatin.c
+++ b/src/autofit/aflatin.c
@@ -2809,13 +2809,18 @@ af_remove_segments_containing_point(AF_GlyphHints 
hints, AF_Point point)
   {
     AF_Segment seg = &segments[i];
     FT_Bool remove = 0;
-    for ( AF_Point p = seg->first; p <= seg->last; p = p->next )
+    AF_Point p = seg->first;
+    while ( 1 )
     {
       if ( p == point )
       {
         remove = 1;
         break;
       }
+      if (p == seg->last) {
+        break;
+      }
+      p = p->next;
     }
 
     if ( remove )
@@ -2856,7 +2861,7 @@ af_latin_stretch_tildes_step_2( AF_GlyphHints hints,
                                 FT_Int glyph_index,
                                 AF_ReverseCharacterMap reverse_charmap )
 {
-  if (af_lookup_tilde_correction_type(reverse_charmap, glyph_index)) {
+  if (af_lookup_tilde_correction_type(reverse_charmap, glyph_index) & 1) {
     FT_Int highest_contour = af_find_highest_contour(hints);
     AF_Point first_point = hints->contours[highest_contour];
 
@@ -2872,18 +2877,17 @@ af_latin_stretch_tildes_step_2( AF_GlyphHints hints,
             && p->prev->flags & AF_FLAG_CONTROL
             && p->next->flags & AF_FLAG_CONTROL*/ 1 )
       {
+        FT_TRACE4(("%p", p));
         af_remove_segments_containing_point( hints, p );
       }
     } while ( p != first_point );
   }
-
 }
-
 void
 af_latin_stretch_tildes( AF_GlyphHints hints,
                          FT_Int glyph_index,
                          AF_ReverseCharacterMap reverse_charmap ) {
-  if ( af_lookup_tilde_correction_type( reverse_charmap, glyph_index ) ) {
+  if ( af_lookup_tilde_correction_type( reverse_charmap, glyph_index ) & 2 ) {
     FT_Int highest_contour = af_find_highest_contour( hints );
     AF_Point p = hints->contours[highest_contour];
     AF_Point first_point = p;
@@ -4116,7 +4120,7 @@ static void traceheight(FT_UInt num, AF_GlyphHints hints) 
{
 
     if ( AF_HINTS_DO_VERTICAL( hints ) )
     {
-      /*af_latin_stretch_tildes( hints, glyph_index, 
metrics->root.reverse_charmap );*/
+      af_latin_stretch_tildes( hints, glyph_index, 
metrics->root.reverse_charmap );
       axis  = &metrics->axis[AF_DIMENSION_VERT];
       error = af_latin_hints_detect_features( hints,
                                               axis->width_count,