def ttf.coverage.ranges

gralha-truetype@0.1.0.1 · font.bend:585

import Base
import gralha-text-scan@0.1.0.1/scan.bend as U
import gralha-bytes@0.1.0.1/bytes.bend as Bin

585def ttf.coverage.ranges(+b: Bin.Bytes, fuel: Nat, +base: U32, +lo: U32, +hi: U32, +gid: U32) -> U32:
586  match fuel:
587    case 0n: 0
588    case 1n+d:
589      +dd = d
590      +mid = U32.div((lo + hi : U32), 2)
591      +at = (base + mid * 6 : U32)
592      +start = ttf.u16(b, at)
593      +end = ttf.u16(b, (at + 2 : U32))
594      U.branch(U32, U32.is_ge(lo, hi), _ => 0,
595        _ => U.branch(U32, U32.is_lt(gid, start), _ => ttf.coverage.ranges(b, dd, base, lo, mid, gid),
596          _ => U.branch(U32, U32.is_gt(gid, end), _ => ttf.coverage.ranges(b, dd, base, (mid + 1 : U32), hi, gid),
597            _ => (ttf.u16(b, (at + 4 : U32)) + gid - start + 1 : U32))))