//! Hash functions and hash utilities

/// Compute a CRC32 hash from the given `bytes`, returning the CRC32 hash.

///

/// When calling this function for the first time, `previous_value` should be `0`.

/// Otherwise, it should be the previous return value of this function to provide a hash

/// of multiple sequential chunks of `bytes`.

#[cfg(feature = "crc32")]

pub fn crc32_update(previous_value: u32, bytes: &[u8]) -> u32 {

    let mut h = crc32fast::Hasher::new_with_initial(previous_value);

    h.update(bytes);

    h.finalize()

}

/// Compute a CRC32 value of the given input `bytes`.

///

/// In case multiple chunks of `bytes` are present, one should use [`crc32_update()`] instead.

#[cfg(feature = "crc32")]

pub fn crc32(bytes: &[u8]) -> u32 {

    let mut h = crc32fast::Hasher::new();

    h.update(bytes);

    h.finalize()

}