hash.cpp

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/***
 * Bitwuzla: Satisfiability Modulo Theories (SMT) solver.
 *
 * Copyright (C) 2025 by the authors listed in the AUTHORS file at
 * https://github.com/bitwuzla/bitwuzla/blob/main/AUTHORS
 *
 * This file is part of Bitwuzla under the MIT license. See COPYING for more
 * information at https://github.com/bitwuzla/bitwuzla/blob/main/COPYING
 */
// Modified by Xiang Zhang, 2026
// Additional changes licensed under the MIT License
#include "util/hash.h"
 
namespace {
uint64_t fnv1a_64(uint64_t v, uint64_t hash = 14695981039346656037u) {
    hash ^= v;
    // Compute (hash * 1099511628211)
    return hash + (hash << 1) + (hash << 4) + (hash << 5) + (hash << 7) +
           (hash << 8) + (hash << 40);
}
}  // namespace
 
size_t std::hash<std::pair<uint64_t, uint64_t>>::operator()(
    const std::pair<uint64_t, uint64_t> &p) const {
    uint64_t hash = fnv1a_64(std::hash<uint64_t>()(p.first));
    return static_cast<size_t>(fnv1a_64(std::hash<uint64_t>()(p.second), hash));
}