Read the native container beyond its preview: the chain of allocation
tables (#FAT, #FT2, #FT3, #FT4) with newest-revision selection, CRC-checked
extraction of stored, zlib and zstd entries with their byte predictors,
and the self-describing tagged object stream in doc.dat as a generic tree
of shared, inline and positional objects.
Every declared size is checked against per-entry and per-import budgets
before allocation; the zstd window is capped at 64 MiB; table chains are
cycle-checked; arrays are checked against the remaining bytes; object
nesting stops at 384 levels.
The header now accepts container versions 8 to 12 and the flag values 4
and 8 that real Affinity 3 files carry (the previous check rejected the
public CC0 Affinity 3 documents); the thumbnail record is the same in all
those versions. Checked against 176 public documents saved by Affinity 1.x
to 3.x: every doc.dat decompresses with a matching CRC and parses with no
bytes left over.
A test-only `synth` feature builds synthetic containers for unit tests
and fuzz seeds; it is not an Affinity exporter.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01GQPh8UDgMyARR5Hat9UchC
Riccardo Balloch