sysl.checksum

A CRC is not a hash in the sense sysl.crypto means. Anyone can build a second input with the same CRC-32 on purpose, so it must never stand in for a digest where an attacker gains from a collision. It is what zip, gzip, PNG and Ethernet put on the wire, and for those it is exactly right.

Index

crc32_poly crc32_table crc32 make_crc32_table new_crc32 Crc32

Constants

crc32_poly

const crc32_poly: u32 = 3988292384

Values

crc32_table

val crc32_table: [256]u32 = make_crc32_table()

Functions

crc32

crc32(data: []const u8) -> u32

The CRC-32 of one slice of bytes: initial value and final xor 0xffffffff, polynomial 0xedb88320 reflected. crc32("123456789".bytes) is 0xcbf43926, the standard check value, and the empty input is 0.

make_crc32_table

const make_crc32_table() -> [256]u32

new_crc32

new_crc32() -> Crc32

A checksum ready for its first update.

Types

Crc32

struct Crc32
    private state: u32

A CRC-32 in progress, for input that arrives in pieces.

It is an ordinary struct, so copying one starts another from the same point. update may be called as often as you like and finish answers the checksum so far without ending anything.