lib/src/cbor.dart is the port of codec/codec.go: CborEncoder,
CborDecoder, unmarshalCbor, peekSchema, checkSchema and walkCbor, with
the same reads, the same checks in the same order and the same error
texts, such as "codec: offset 0: 23 is not in its shortest form
(initial byte 0x18): ERR_NON_CANONICAL_CBOR".
Integers are exact on the VM and on the web, where an int is a double
and the bit operators work on 32 bits. An argument of eight bytes is
read as two halves of 32 bits, and is an int up to 2^53-1 and a BigInt
above, map keys and the numbers of the error texts included. uint
returns an int, since every schema bounds its integers at 2^53-1, and
uint64 a BigInt. The map that peekSchema reads is bounded at 2^63-1,
Go's math.MaxInt, on the web too.
Two kinds of text are of Dart only. CborEncoder.uint refuses an int
outside 0..2^53-1 and uint64 a BigInt outside 0..2^64-1, with the text
of datekeys-ts, where Go's uint64 cannot hold such a value. And the only
invalid text that a Dart String holds is a lone surrogate: the error
quotes it as Go quotes its bytes in generalized UTF-8.
The tests port codec_test.go, internal_test.go and vectors_test.go,
with the texts that Go prints, and cbor.test.ts. The fuzz targets are
properties over seeded inputs, checked against a reference encoder and
decoder written apart, as internal/cbortest. cbor.json runs its 36
accept and 67 reject vectors with the walk limits and the values; its
172 schema vectors are read and wait for the schema decoders of stage 4.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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