Function validate_hash_bytes 

pub const fn validate_hash_bytes(bytes: &[u8]) -> Result<(), VctrlError>

Validates that a byte slice is exactly HASH_LENGTH bytes long.

Purpose

This function acts as a gatekeeper to ensure that any byte slice intended to represent a Hash meets the strict length invariant (64 bytes) required by the system.

Design rationale

• const fn: Being a const fn allows this check to be evaluated during compilation if the inputs are known constants. This is useful for verifying hardcoded hashes in configuration or test vectors.
• Pre-conditions Check: It is often used as a pre-check before calling Hash::from_bytes to provide custom error handling or logging before the actual conversion.

Internal mechanism

The function performs an O(1) comparison between the length of the provided slice and the constant HASH_LENGTH. If they differ, it returns a VctrlError::InvalidHashLength containing the incorrect length.

Errors

Returns VctrlError::InvalidHashLength if the length of bytes is not exactly equal to HASH_LENGTH (64).

Examples

Validating a correctly sized slice:

use libvctrl_core::validate::hash::validate_hash_bytes;
use libvctrl_handler::HASH_LENGTH;

let valid_bytes = [0u8; HASH_LENGTH];
assert!(validate_hash_bytes(&valid_bytes).is_ok());

Validating an incorrectly sized slice:

use libvctrl_core::validate::hash::validate_hash_bytes;
use libvctrl_handler::{HASH_LENGTH, VctrlError};

let invalid_bytes = [0u8; 32]; // Wrong length
let result = validate_hash_bytes(&invalid_bytes);

assert!(matches!(result, Err(VctrlError::InvalidHashLength(32))));