Fix a crash in the woff2 encoder when it encounters a loca table with a length of zero.

2017-07-19 17:35:13 -07:00
parent 4f659ddbad
commit 849bdb0d24
1 changed files with 5 additions and 2 deletions
@@ -331,8 +331,11 @@ int NumGlyphs(const Font& font) {
    return 0;
  }
  int index_fmt = IndexFormat(font);
-  int num_glyphs = (loca_table->length / (index_fmt == 0 ? 2 : 4)) - 1;
-  return num_glyphs;
+  int loca_record_size = (index_fmt == 0 ? 2 : 4);
+  if (loca_table->length < loca_record_size) {
+    return 0;
+  }
+  return (loca_table->length / loca_record_size) - 1;
 }

 int IndexFormat(const Font& font) {