Struct rolling_dual_crc::RollingDualCrc

pub struct RollingDualCrc { /* fields omitted */ }

Computes 32-bit CRC-32C and 64-bit CRC-64/XZ checksums in a rolling window that moves through the input data.

Examples

Compute checksums of 3-byte windows of "abcde", i.e. "abc", "bcd" and "cde".

use rolling_dual_crc::RollingDualCrc;

let mut crc = RollingDualCrc::new("abc");

// checksum of "abc"
assert_eq!(crc.get32(), 0x364B3FB7);

crc.roll(b'd');
// checksum of "bcd"
assert_eq!(crc.get32(), 0x1B0D0358);

crc.roll(b'e');
// checksum of "cde"
assert_eq!(crc.get32(), 0x364ADB60);

Implementations

impl RollingDualCrc

pub fn get(&self) -> (u32, u64)

Returns 32-bit CRC-32C and 64-bit CRC-64/XZ checksums of the current window.

Examples

use rolling_dual_crc::RollingDualCrc;

let mut crc = RollingDualCrc::new("abc");
crc.roll(b'd');
// checksums of "bcd"
assert_eq!(crc.get(), (0x1B0D0358, 0x0557EA6AA1219070));

pub fn get32(&self) -> u32

Returns 32-bit CRC-32C checksum of the current window.

Examples

use rolling_dual_crc::RollingDualCrc;

let mut crc = RollingDualCrc::new("abc");
crc.roll(b'd');
// checksum of "bcd"
assert_eq!(crc.get32(), 0x1B0D0358);

pub fn get64(&self) -> u64

Returns 64-bit CRC-64/XZ checksum of the current window.

Examples

use rolling_dual_crc::RollingDualCrc;

let mut crc = RollingDualCrc::new("abc");
crc.roll(b'd');
// checksum of "bcd"
assert_eq!(crc.get64(), 0x0557EA6AA1219070);

pub fn new<T: AsRef<[u8]>>(initial_window: T) -> Self

Begins computation of 32-bit CRC-32C and 64-bit CRC-64/XZ rolling checksums.

• Sets window_size to size of the given initial window. (window_size remains same during rolling.)
• Allocates and initializes buffer of window_size bytes for the window contents.
• Allocates and initializes local lookup tables (3 kiB total).
• Computes checksums of initial window.

Panics

Panics if initial_window is empty.

Examples

use rolling_dual_crc::RollingDualCrc;

let mut crc = RollingDualCrc::new("abc");
// checksum of "abc"
assert_eq!(crc.get32(), 0x364B3FB7);

pub fn roll(&mut self, data: u8)

Rolls window forward one byte.

• Appends the given byte to the window.
• Removes first byte of the window.
• Recomputes checksums for the new window.

This is a fast constant time Θ(1) operation which doesn’t depend on the size of the window.

Examples

use rolling_dual_crc::RollingDualCrc;

let mut crc = RollingDualCrc::new("abc");
crc.roll(b'd');
// checksum of "bcd"
assert_eq!(crc.get32(), 0x1B0D0358);

pub fn roll_slice<T: AsRef<[u8]>>(&mut self, data: T)

Rolls window forward.

This is equivalent to calling roll for each byte of the given slice.

Examples

use rolling_dual_crc::RollingDualCrc;

let mut crc = RollingDualCrc::new("abc");
crc.roll_slice("de");
// checksum of "cde"
assert_eq!(crc.get32(), 0x364ADB60);

Trait Implementations

impl Clone for RollingDualCrc

fn clone(&self) -> RollingDualCrc

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for RollingDualCrc

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.