pub fn physical_offset_for(raw_id: u64, feature_flags: u32) -> u64Expand description
Phase 4 (issue #9): byte offset of page raw_id’s on-disk slot
for a file with the given feature_flags.
Page 0 is always at offset 0 (4096 bytes, plaintext). Pages 1..N
stride by physical_page_stride starting at byte 4096.
Total function: arithmetic uses u64, and a realistic file is
orders of magnitude below u64::MAX / stride. Returns
u64::MAX only on a contrived overflow input — the pager’s
alloc_fresh checks the resulting file length against a real
set_len call which surfaces an EINVAL-style I/O error well
below this saturation point.