hash_utils.hpp

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// === AUDIT STATUS ===
// internal:    { status: Complete, auditors: [Luke], commit: dd03c4a23ab067274b4964cacb36d1545f73fb14}
// external_1:  { status: not started, auditors: [], commit: }
// external_2:  { status: not started, auditors: [], commit: }
// =====================
 
#pragma once
 
#include "barretenberg/stdlib/primitives/field/field.hpp"
#include "barretenberg/stdlib/primitives/witness/witness.hpp"
 
namespace bb::stdlib::hash_utils {
 
template <typename Builder>
field_t<Builder> add_normalize_unsafe(const field_t<Builder>& a, const field_t<Builder>& b, size_t overflow_bits)
{
    using field_pt = field_t<Builder>;
    using witness_pt = witness_t<Builder>;
 
    Builder* ctx = a.get_context() ? a.get_context() : b.get_context();
 
    uint256_t sum = a.get_value() + b.get_value();
    uint256_t normalized_sum = static_cast<uint32_t>(sum.data[0]); // lower 32 bits
 
    if (a.is_constant() && b.is_constant()) {
        return field_pt(ctx, normalized_sum);
    }
 
    fr overflow_value = fr((sum - normalized_sum) >> 32);
    field_pt overflow = witness_pt(ctx, overflow_value);
 
    field_pt result = a.add_two(b, overflow * field_pt(ctx, -fr(1ULL << 32ULL)));
    overflow.create_range_constraint(overflow_bits);
    return result;
}
 
} // namespace bb::stdlib::hash_utils