set_membership_proof_variable.tcc

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/**
 *****************************************************************************
 * @author     This file is part of libsnark, developed by SCIPR Lab
 *             and contributors (see AUTHORS).
 * @copyright  MIT license (see LICENSE file)
 *****************************************************************************/
 
#ifndef SET_MEMBERSHIP_PROOF_VARIABLE_TCC_
#define SET_MEMBERSHIP_PROOF_VARIABLE_TCC_
 
namespace libsnark
{
 
template<typename FieldT, typename HashT>
set_membership_proof_variable<FieldT, HashT>::set_membership_proof_variable(
    protoboard<FieldT> &pb,
    const size_t max_entries,
    const std::string &annotation_prefix)
    : gadget<FieldT>(pb, annotation_prefix)
    , max_entries(max_entries)
    , tree_depth(libff::log2(max_entries))
{
    if (tree_depth > 0) {
        address_bits.allocate(
            pb, tree_depth, FMT(annotation_prefix, " address_bits"));
        merkle_path.reset(
            new merkle_authentication_path_variable<FieldT, HashT>(
                pb, tree_depth, FMT(annotation_prefix, " merkle_path")));
    }
}
 
template<typename FieldT, typename HashT>
void set_membership_proof_variable<FieldT, HashT>::generate_r1cs_constraints()
{
    if (tree_depth > 0) {
        for (size_t i = 0; i < tree_depth; ++i) {
            generate_boolean_r1cs_constraint<FieldT>(
                this->pb,
                address_bits[i],
                FMT(this->annotation_prefix, " address_bits"));
        }
        merkle_path->generate_r1cs_constraints();
    }
}
 
template<typename FieldT, typename HashT>
void set_membership_proof_variable<FieldT, HashT>::generate_r1cs_witness(
    const set_membership_proof &proof)
{
    if (tree_depth > 0) {
        address_bits.fill_with_bits_of_field_element(
            this->pb, FieldT(proof.address));
        merkle_path->generate_r1cs_witness(proof.address, proof.merkle_path);
    }
}
 
template<typename FieldT, typename HashT>
set_membership_proof set_membership_proof_variable<FieldT, HashT>::
    get_membership_proof() const
{
    set_membership_proof result;
 
    if (tree_depth == 0) {
        result.address = 0;
    } else {
        result.address =
            address_bits.get_field_element_from_bits(this->pb).as_ulong();
        result.merkle_path =
            merkle_path->get_authentication_path(result.address);
    }
 
    return result;
}
 
template<typename FieldT, typename HashT>
r1cs_variable_assignment<FieldT> set_membership_proof_variable<FieldT, HashT>::
    as_r1cs_variable_assignment(const set_membership_proof &proof)
{
    protoboard<FieldT> pb;
    const size_t max_entries = (1ul << (proof.merkle_path.size()));
    set_membership_proof_variable<FieldT, HashT> proof_variable(
        pb, max_entries, "proof_variable");
    proof_variable.generate_r1cs_witness(proof);
 
    return pb.full_variable_assignment();
}
 
} // namespace libsnark
 
#endif // SET_MEMBERSHIP_PROOF_VARIABLE_TCC