Home › crypto/crc32

Module crypto/crc32

crypto/crc32
Stability: unstable for one reason that has nothing to do with the algorithm: the CRC-32 answer is pinned by IEEE 802.3 and checked against the catalogue value (`tests/crypto/digest.test.yo`), but the module lives under `std/crypto` while being explicitly NOT cryptographic, and it is the only thing here that is a checksum. Whether it moves (a `std/hash` or `std/encoding` neighbourhood, next to the archive formats that need it) is unsettled, and moving it changes every import path. The implementation is also deliberately the slow one — a bitwise byte step rather than a 256-entry table, as the `_crc32_byte` comment says — so a table-driven rewrite is expected; that one is invisible to callers. There is no incremental form (no `Crc32` state type), so a stream has to be hashed as one `ArrayList(u8)`; adding one would be additive. — stable modules only change additively; this one may still change.

CRC-32 (IEEE 802.3, reflected, polynomial 0xEDB88320) — the checksum zip/png/gzip use (plans/archive/STD_API_AUDIT.md §7 P0 item 7). NOT a cryptographic hash — it detects accidental corruption only.

Stability

unstable for one reason that has nothing to do with the algorithm: the CRC-32 answer is pinned by IEEE 802.3 and checked against the catalogue value (tests/crypto/digest.test.yo), but the module lives under std/crypto while being explicitly NOT cryptographic, and it is the only thing here that is a checksum. Whether it moves (a std/hash or std/encoding neighbourhood, next to the archive formats that need it) is unsettled, and moving it changes every import path. The implementation is also deliberately the slow one — a bitwise byte step rather than a 256-entry table, as the _crc32_byte comment says — so a table-driven rewrite is expected; that one is invisible to callers. There is no incremental form (no Crc32 state type), so a stream has to be hashed as one ArrayList(u8); adding one would be additive.

Functions

crc32 function
fn(data : ArrayList(u8)) -> u32

CRC-32 of data (init 0xFFFFFFFF, final xor 0xFFFFFFFF).

Parameters

NameTypeNotes
dataArrayList(u8)

Returns: u32