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[gvar] fix infinite loop introduced by 11f3fca 

The attempt on removing end_points had made the code unreadable
and has intrdouced infinite, fixed by making the code clear what
it tries to achieve.
This commit is contained in:
Ebrahim Byagowi 2020-02-24 13:18:24 +03:30
parent f00eb4ebfa
commit 1f5a54c768
3 changed files with 34 additions and 6 deletions
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22
src/hb-ot-var-gvar-table.hh
View File

@ -625,17 +625,27 @@ struct gvar
deltas[pt_index].y += y_deltas[i] * scalar;
}
/* find point before phantoms start which is an end point */
unsigned all_contours_end = points.length ? points.length - 1 : 0;
while (all_contours_end > 0)
{
if (points[all_contours_end].is_end_point) break;
--all_contours_end;
}
/* infer deltas for unreferenced points */
for (unsigned start_point = 0; start_point + 4 < points.length; ++start_point)
for (unsigned start_point = 0; start_point < all_contours_end; ++start_point)
{
/* Check the number of unreferenced points in a contour. If no unref points or no ref points, nothing to do. */
unsigned unref_count = 0;
unsigned end_point = start_point;
do
unsigned unref_count = 0;
for (; end_point <= all_contours_end; ++end_point)
{
if (!deltas[end_point].flag) unref_count++;
end_point++;
} while (!points[end_point].is_end_point && end_point + 4 < points.length);
if (!deltas[end_point].flag)
unref_count++;
if (points[end_point].is_end_point)
break;
}
unsigned j = start_point;
if (unref_count == 0 || unref_count > end_point - start_point)

BIN
test/api/fonts/TestGVAREight.ttf Normal file
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18
test/api/test-ot-metrics-tt-var.c
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@ -234,6 +234,23 @@ test_advance_tt_var_comp_v (void)
hb_font_destroy (font);
}
static void
test_advance_tt_var_gvar_infer (void)
{
hb_face_t *face = hb_test_open_font_file ("fonts/TestGVAREight.ttf");
hb_font_t *font = hb_font_create (face);
hb_ot_font_set_funcs (font);
hb_face_destroy (face);
int coords[6] = {100};
hb_font_set_var_coords_normalized (font, coords, 6);
hb_glyph_extents_t extents = {0};
g_assert (hb_font_get_glyph_extents (font, 4, &extents));
hb_font_destroy (font);
}
int
main (int argc, char **argv)
{
@ -245,6 +262,7 @@ main (int argc, char **argv)
hb_test_add (test_advance_tt_var_anchor);
hb_test_add (test_extents_tt_var_comp);
hb_test_add (test_advance_tt_var_comp_v);
hb_test_add (test_advance_tt_var_gvar_infer);
return hb_test_run ();
}