The binary searches within charmaps can be accelerated because they
often contain dense continuous blocks of character codes. Within such
blocks, you can predict matches based on misses. This method has been
deployed in `bdf` since 0f122fef34; we only refactor it there. We now
use it in `pfr` and `psnames`, which speeds up the unicode charmap
access by about 50% in PFR and Type 1 fonts.
* src/bdf/bdfdrivr.c (bdf_cmap_char_{index,next}): Refactor.
* src/pfr/pfrcmap.c (pfr_cmap_char_{index,next}): Predict `mid` based
on the mismatch distance.
* src/psnames/psmodule.c (ps_unicodes_char_{index,next}): Ditto.
Any array index must be strictly less then the array size. Therefore,
we must reject indexes that are equal to the array size. Alternatively,
we should move the bounds check before the index decrement but that
would be confusing.
In addition, it is ok to decrement zero (.notdef) and get UINT_MAX,
which is then automatically rejected in the bounds check.
* src/pfr/pfrobjs.c (pfr_face_get_kerning): Fix the bounds checking.
* src/sfnt/ttcolr.c (FT_PaintFormat_Internal): New enumeration values
`FT_COLR_PAINTFORMAT_INTERNAL_VAR_SKEW`,
`FT_COLR_PAINTFORMAT_INTERNAL_SKEW_CENTER`, and
`FT_COLR_PAINTFORMAT_INTERNAL_VAR_SKEW_CENTER`.
(read_paint): Handle new enumeration values.
Alexei Podtelezhnikov
Werner Lemberg
Dominik Röttsches