qubit-value 0.11.0

Type-safe containers for single, multi-valued, and named runtime values
Documentation 
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// =============================================================================
//    Copyright (c) 2025 - 2026 Haixing Hu.
//
//    SPDX-License-Identifier: Apache-2.0
//
//    Licensed under the Apache License, Version 2.0.
// =============================================================================
//! Iteration-order-independent hashing for string maps.

use std::collections::HashMap;
use std::hash::BuildHasher;
use std::hash::BuildHasherDefault;
use std::hash::Hash;
use std::hash::Hasher;

/// Stable standard hasher used for each order-independent map entry.
type IdentityHasher = BuildHasherDefault<std::collections::hash_map::DefaultHasher>;

/// Hashes a string map independently of its iteration order.
///
/// # Type Parameters
///
/// * `H` - Hasher receiving the order-independent map identity.
///
/// # Parameters
///
/// * `value` - Map to hash.
/// * `state` - Destination hasher.
pub(crate) fn hash_string_map<H: Hasher>(value: &HashMap<String, String>, state: &mut H) {
    value.len().hash(state);
    let mut sum = 0_u64;
    let mut xor = 0_u64;
    for (key, value) in value {
        let mut entry = IdentityHasher::default().build_hasher();
        key.hash(&mut entry);
        value.hash(&mut entry);
        let hash = entry.finish();
        sum = sum.wrapping_add(hash);
        xor ^= hash.rotate_left(17);
    }
    sum.hash(state);
    xor.hash(state);
}