Parsers for the TrueType glyph outline tables, loca and glyf.

loca is an offset table locating each glyph's outline within glyf; a glyph whose start and end offsets are equal has no outline at all, which is how the space character and every other non-marking glyph is encoded.

glyf entries are either simple outlines or composites that reference other glyphs by index, so following a composite means walking a reference graph that a malformed font can make cyclic or self-referential.

Extracted from Tincture.Font.TTF.