std/crc64

Index

• type Poly
• fn checksum
• fn update

Types

Poly

enum Poly {
  Iso
  Ecma
  Nvme
}

The polynomial: Go’s ISO (0xd800000000000000) and ECMA (0xc96c5795d7870f42) tables, both reversed as Go’s are, and NVMe’s (0x9a6c9329ac4bc9b5 reversed, CRC-64/NVME: Amazon S3’s default flexible checksum; checksum(b"123456789", Poly.Nvme) is 0xae8b14860a799888 as a Go uint64).

Source: std/crc64.xo:11

Functions

checksum

fn checksum(data: Bytes, poly: Poly = Poly.Iso) -> Int

The CRC-64 of data: the Int’s bits are Go’s uint64, so a checksum past 2^63 is negative (Go’s Checksum with MakeTable(poly)).

Source: std/crc64.xo:19

update

fn update(crc: Int, data: Bytes, poly: Poly = Poly.Iso) -> Int

The CRC-64 of what crc was the checksum of, followed by data (Go’s Update): update(checksum(a), b) == checksum(a + b), and update(0, d) == checksum(d).

Source: std/crc64.xo:23