awaforge

Primitives

AGPL-3.0-onlyRelease 2L4

Low-level building blocks shared by every OpenType table — binary, numeric and text encodings.

Module Returns Deps Description
fixed {fixedFromInt32, ...} none Fixed 16.16 / F2Dot14 / version16Dot16.
tag {tag, untag, tagEquals} fontErrors 4-char ASCII tag ↔ uint32 BE.
reader {BinaryReader, reader, sliceTable} fontErrors, binaryReader, fontFixed Big-endian binary reader.
writer {BinaryWriter, writer} fontErrors, binaryWriter, fontFixed Big-endian binary writer.
checksum {calcTableChecksum, computeChecksumAdjustment} none OT checksum + head adjustment.
encoding {decodeUtf16Be, ...} fontErrors UTF-16BE and Mac Roman for name.

Common pattern

const r = runtime.resolve('fontReader').reader(bytes);
const w = runtime.resolve('fontWriter').writer();
// ... typed BE read / write ...

Why a facade over @awacloud/fw

Since v1.0.0, BinaryReader / BinaryWriter delegate the primitives (u8/u16/u24/u32, i8/i16/i32, bytes, seek) to @awacloud/fw/io/binary/{reader,writer}.js. The facade nevertheless stays non-redundant for the following reasons:

  • OpenType-specific API: readFixed, readF2Dot14, readTag, readLongDateTime, readOffset16/32, peek(fn), sub(start, len), writeTag, writeLongDateTime, padTo4/padTo, patchUint16/32. None of these helpers belong in a generic BE module.
  • Error hierarchy: the facade translates fw's ContractError into the fonts package's ParseError (fonts/reader-*, fonts/writer-*). Without this translation, callers would have to branch on two disjoint hierarchies for identical errors.
  • Windowing at construction: new BinaryReader(bytes, start, length) materializes a sub-buffer with no allocation, which fw only exposes via create(view, opts). The facade derives the view itself.
  • Documented invariants: readBytes shares the source buffer; writeTag rejects non-ASCII characters; readLongDateTime preserves precision beyond 2^32. These three invariants are covered by tests in src/primitives/reader.test.js and writer.test.js.