jeffro256
572 lines
30 KiB
C++
572 lines
30 KiB
C++
// Copyright (c) 2024, The Monero Project
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//
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// All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without modification, are
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// permitted provided that the following conditions are met:
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//
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// 1. Redistributions of source code must retain the above copyright notice, this list of
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// conditions and the following disclaimer.
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//
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// 2. Redistributions in binary form must reproduce the above copyright notice, this list
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// of conditions and the following disclaimer in the documentation and/or other
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// materials provided with the distribution.
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//
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// 3. Neither the name of the copyright holder nor the names of its contributors may be
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// used to endorse or promote products derived from this software without specific
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// prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
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// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
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// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
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// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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//paired header
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#include "input_selection.h"
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//local headers
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#include "carrot_core/config.h"
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#include "common/container_helpers.h"
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#include "cryptonote_basic/cryptonote_format_utils.h"
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#include "misc_log_ex.h"
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//third party headers
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//standard headers
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#include <algorithm>
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#undef MONERO_DEFAULT_LOG_CATEGORY
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#define MONERO_DEFAULT_LOG_CATEGORY "carrot_impl"
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namespace carrot
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{
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//-------------------------------------------------------------------------------------------------------------------
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//-------------------------------------------------------------------------------------------------------------------
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static int compare_input_candidate_same_ki(const CarrotPreSelectedInput &lhs, const CarrotPreSelectedInput &rhs)
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{
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CHECK_AND_ASSERT_THROW_MES(lhs.core.key_image == rhs.core.key_image,
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"compare_input_candidate_same_ki: this function is not meant to compare inputs of different key images");
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// first prefer the higher amount
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if (lhs.core.amount < rhs.core.amount)
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return -1;
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else if (lhs.core.amount > rhs.core.amount)
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return 1;
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// then prefer older
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if (lhs.block_index < rhs.block_index)
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return 1;
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else if (lhs.block_index > rhs.block_index)
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return -1;
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// It should be computationally intractable for lhs.is_external != rhs.is_external, but I haven't
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// looked into it too deeply. I guess you would want to prefer whichever one !is_external.
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return 0;
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}
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//-------------------------------------------------------------------------------------------------------------------
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//-------------------------------------------------------------------------------------------------------------------
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static std::set<size_t> set_union(const std::set<size_t> &a, const std::set<size_t> &b)
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{
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std::set<size_t> c = a;
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c.merge(std::set<size_t>(b));
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return c;
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};
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//-------------------------------------------------------------------------------------------------------------------
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//-------------------------------------------------------------------------------------------------------------------
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static void stable_sort_indices_by_amount(const epee::span<const CarrotPreSelectedInput> input_candidates,
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std::vector<size_t> &indices_inout)
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{
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std::stable_sort(indices_inout.begin(), indices_inout.end(),
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[input_candidates](const size_t a, const size_t b) -> bool
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{
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CHECK_AND_ASSERT_THROW_MES(a < input_candidates.size() && b < input_candidates.size(),
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"input candidate index out of range");
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return input_candidates[a].core.amount < input_candidates[b].core.amount;
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});
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}
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//-------------------------------------------------------------------------------------------------------------------
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//-------------------------------------------------------------------------------------------------------------------
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static void stable_sort_indices_by_block_index(const epee::span<const CarrotPreSelectedInput> input_candidates,
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std::vector<size_t> &indices_inout)
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{
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std::stable_sort(indices_inout.begin(), indices_inout.end(),
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[input_candidates](const size_t a, const size_t b) -> bool
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{
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CHECK_AND_ASSERT_THROW_MES(a < input_candidates.size() && b < input_candidates.size(),
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"input candidate index out of range");
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return input_candidates[a].block_index < input_candidates[b].block_index;
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});
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}
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//-------------------------------------------------------------------------------------------------------------------
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//-------------------------------------------------------------------------------------------------------------------
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static std::pair<size_t, boost::multiprecision::int128_t> input_count_for_max_usable_money(
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const epee::span<const CarrotPreSelectedInput> input_candidates,
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const std::set<size_t> &selectable_inputs,
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const std::map<size_t, rct::xmr_amount> &fee_by_input_count)
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{
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// Returns (N, X) where the X is the sum of the amounts of the greatest N <= CARROT_MAX_TX_INPUTS
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// inputs from selectable_inputs, maximizing X - F(N). F(N) is the fee for this transaction,
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// given input count N. This should correctly handle "almost-dust": inputs which are less than
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// the fee, but greater than or equal to the difference of the fee compared to excluding that
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// input. If this function returns N == 0, then there aren't enough usable funds, i.e. no N
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// exists such that X - F(N) > 0.
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size_t num_ins = 0;
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boost::multiprecision::int128_t cumulative_input_sum = 0;
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rct::xmr_amount last_fee = 0;
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std::vector<size_t> selectable_inputs_vec(selectable_inputs.cbegin(), selectable_inputs.cend());
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stable_sort_indices_by_amount(input_candidates, selectable_inputs_vec);
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// for selectable indices in descending amount...
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for (auto it = selectable_inputs_vec.crbegin(); it != selectable_inputs_vec.crend(); ++it)
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{
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if (num_ins == CARROT_MAX_TX_INPUTS)
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break;
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++num_ins;
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const rct::xmr_amount amount = input_candidates[*it].core.amount;
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if (amount < fee_by_input_count.at(num_ins) - last_fee)
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{
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// then this input doesn't pay for itself, rollback previous state and break
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// since all next inputs will have same amount or less
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--num_ins;
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break;
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}
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cumulative_input_sum += amount;
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last_fee = fee_by_input_count.at(num_ins);
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}
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return {num_ins, cumulative_input_sum};
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}
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//-------------------------------------------------------------------------------------------------------------------
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select_inputs_func_t make_single_transfer_input_selector(
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const epee::span<const CarrotPreSelectedInput> input_candidates,
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const epee::span<const input_selection_policy_t> policies,
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const std::uint32_t flags,
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std::set<size_t> *selected_input_indices_out)
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{
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using namespace InputSelectionFlags;
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CHECK_AND_ASSERT_THROW_MES(!policies.empty(),
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"make_single_transfer_input_selector: no input selection policies provided");
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// Sanity check flags
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const bool confused_qfs = (flags & ALLOW_PRE_CARROT_INPUTS_IN_NORMAL_TRANSFERS) &&
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!(flags & ALLOW_EXTERNAL_INPUTS_IN_NORMAL_TRANSFERS);
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CHECK_AND_ASSERT_THROW_MES(!confused_qfs,
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"make single transfer input selector: It does not make sense to allow pre-carrot inputs in normal transfers, "
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"but not external carrot inputs.");
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// input selector :)
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return [=](const boost::multiprecision::int128_t &nominal_output_sum,
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const std::map<std::size_t, rct::xmr_amount> &fee_by_input_count,
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const std::size_t num_normal_payment_proposals,
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const std::size_t num_selfsend_payment_proposals,
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std::vector<CarrotSelectedInput> &selected_inputs_out)
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{
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// 1. Compile map of best input candidates by key image to mitigate the "burning bug" for legacy enotes
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std::unordered_map<crypto::key_image, size_t> best_input_by_key_image;
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for (size_t i = 0; i < input_candidates.size(); ++i)
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{
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const CarrotPreSelectedInput &input_candidate = input_candidates[i];
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auto it = best_input_by_key_image.find(input_candidate.core.key_image);
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if (it == best_input_by_key_image.end())
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{
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best_input_by_key_image[input_candidate.core.key_image] = i;
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}
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else
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{
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const CarrotPreSelectedInput &other_input_candidate = input_candidates[it->second];
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if (compare_input_candidate_same_ki(other_input_candidate, input_candidate) < 0)
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it->second = i;
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}
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}
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// 2. Collect set of non-burned inputs
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std::set<size_t> all_non_burned_inputs;
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for (const auto &best_input : best_input_by_key_image)
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all_non_burned_inputs.insert(best_input.second);
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// 3. Partition into:
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// a) Pre-carrot (no quantum forward secrecy)
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// b) External carrot (quantum forward secret if public address not known)
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// c) Internal carrot (always quantum forward secret unless secret keys known)
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std::set<size_t> pre_carrot_inputs;
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std::set<size_t> external_carrot_inputs;
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std::set<size_t> internal_inputs;
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for (size_t candidate_idx : all_non_burned_inputs)
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{
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if (input_candidates[candidate_idx].is_pre_carrot)
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pre_carrot_inputs.insert(candidate_idx);
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else if (input_candidates[candidate_idx].is_external)
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external_carrot_inputs.insert(candidate_idx);
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else
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internal_inputs.insert(candidate_idx);
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}
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// 4. Calculate minimum required input money sum for a given input count
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const bool subtract_fee = flags & IS_KNOWN_FEE_SUBTRACTABLE;
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std::map<size_t, boost::multiprecision::int128_t> required_money_by_input_count;
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for (const auto &fee_and_input_count : fee_by_input_count)
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{
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required_money_by_input_count[fee_and_input_count.first] =
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nominal_output_sum + (subtract_fee ? 0 : fee_and_input_count.second);
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}
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// 5. Calculate misc features
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const bool must_use_internal = !(flags & ALLOW_EXTERNAL_INPUTS_IN_NORMAL_TRANSFERS) &&
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(num_normal_payment_proposals != 0);
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const bool allow_mixed_externality = (flags & ALLOW_MIXED_INTERNAL_EXTERNAL) &&
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!must_use_internal;
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const bool must_use_carrot = !(flags & ALLOW_PRE_CARROT_INPUTS_IN_NORMAL_TRANSFERS) &&
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(num_normal_payment_proposals != 0);
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const bool allow_mixed_carrotness = (flags & ALLOW_MIXED_CARROT_PRE_CARROT) &&
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!must_use_carrot;
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// We should prefer to spend non-forward-secret enotes in transactions where all the outputs are going back to
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// ourself. Otherwise, if we spend these enotes while transferring money to another entity, an external observer
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// who A) has a quantum computer, and B) knows one of their public addresses, will be able to trace the money
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// transfer. Such an observer will always be able to tell which view-incoming keys / accounts these
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// non-forward-secrets enotes belong to, their amounts, and where they're spent. So since they already know that
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// information, churning back to oneself doesn't actually reveal that much more additional information.
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const bool prefer_non_fs = num_normal_payment_proposals == 0;
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CHECK_AND_ASSERT_THROW_MES(!must_use_internal || !prefer_non_fs,
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"make_single_transfer_input_selector: bug: must_use_internal AND prefer_non_fs are true");
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// There is no "prefer pre-carrot" variable since in the case that we prefer spending non-forward-secret, we
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// always prefer first spending pre-carrot over carrot, if it is allowed
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// 6. Short-hand functor for dispatching input selection on a subset of inputs
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// Note: Result goes into `selected_inputs_indices`. If already populated, then this functor does nothing
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std::set<size_t> selected_inputs_indices;
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const auto try_dispatch_input_selection =
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[&](const std::set<size_t> &selectable_indices)
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{
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// Return early if already selected inputs or no available selectable
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const bool already_selected = !selected_inputs_indices.empty();
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if (already_selected || selectable_indices.empty())
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return;
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// Return early if not enough money in this selectable set...
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const auto max_usable_money = input_count_for_max_usable_money(input_candidates,
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selectable_indices,
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fee_by_input_count);
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const bool enough_money = max_usable_money.first > 0
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&& max_usable_money.second >= required_money_by_input_count.at(max_usable_money.first);
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if (!enough_money)
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return;
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// For each passed policy and while not already selected inputs, dispatch policy...
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for (size_t policy_idx = 0; policy_idx < policies.size() && selected_inputs_indices.empty(); ++policy_idx)
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policies[policy_idx](input_candidates,
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selectable_indices,
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required_money_by_input_count,
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selected_inputs_indices);
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// Check that returned selected indices were actually selectable
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for (const size_t selected_inputs_index : selected_inputs_indices)
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CHECK_AND_ASSERT_THROW_MES(selectable_indices.count(selected_inputs_index),
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"make_single_transfer_input_selector: bug in policy: returned unselectable index");
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};
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// 8. Try dispatching for non-forward-secret input subsets, if preferred in this context
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if (prefer_non_fs)
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{
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// try getting rid of pre-carrot enotes first, if allowed
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if (!must_use_carrot)
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try_dispatch_input_selection(pre_carrot_inputs);
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// ... then external carrot
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try_dispatch_input_selection(external_carrot_inputs);
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}
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// 9. Try dispatching for internal
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try_dispatch_input_selection(internal_inputs);
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// 10. Try dispatching for non-FS *after* internal, if allowed and not already tried
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if (!must_use_internal || !prefer_non_fs)
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{
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// Spending non-FS inputs in a normal transfer transaction is not ideal, but at least
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// when partition it like this, we aren't "dirtying" the carrot with the pre-carrot, and
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// the internal with the external
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if (!must_use_carrot)
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try_dispatch_input_selection(pre_carrot_inputs);
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try_dispatch_input_selection(external_carrot_inputs);
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}
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// 11. Try dispatching for all non-FS (mixed pre-carrot & carrot external), if allowed
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if (allow_mixed_carrotness)
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{
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// We're mixing carrot/pre-carrot spends here, but avoiding "dirtying" the internal
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try_dispatch_input_selection(set_union(pre_carrot_inputs, external_carrot_inputs));
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}
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// 12. Try dispatching for all carrot, if allowed
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if (allow_mixed_externality)
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{
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// We're mixing internal & external carrot spends here, but avoiding "dirtying" the
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// carrot spends with pre-carrot spends. This will be quantum forward secret iff the
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// adversary doesn't know one of your public addresses
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try_dispatch_input_selection(set_union(external_carrot_inputs, internal_inputs));
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}
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//! @TODO: MRL discussion about whether step 11 or step 12 should go first. In other words,
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// do we prefer to avoid dirtying internal, and protect against quantum adversaries
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// who know your public addresses? Or do we prefer to avoid dirtying w/ pre-carrot,
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// and protect against quantum adversaries with no special knowledge of your public
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// addresses, but whose attacks are only relevant when spending pre-FCMP++ enotes?
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// 13. Try dispatching for everything, if allowed
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if (allow_mixed_carrotness && allow_mixed_externality)
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try_dispatch_input_selection(all_non_burned_inputs);
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// Notice that we don't combine just the pre_carrot_inputs and internal_inputs by themselves
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// 14. Sanity check indices
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CHECK_AND_ASSERT_THROW_MES(!selected_inputs_indices.empty(),
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"make_single_transfer_input_selector: input selection failed");
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CHECK_AND_ASSERT_THROW_MES(*selected_inputs_indices.crbegin() < input_candidates.size(),
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"make_single_transfer_input_selector: bug: selected inputs index out of range");
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// 15. Do a greedy search for inputs whose amount doesn't pay for itself and drop them, logging debug messages
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// Note: this also happens to be optimal if the fee difference between each input count is constant
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bool should_search_for_dust = !(flags & ALLOW_DUST);
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while (should_search_for_dust && selected_inputs_indices.size() > CARROT_MIN_TX_INPUTS)
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{
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should_search_for_dust = false; // only loop again if we remove an input below
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const boost::multiprecision::int128_t fee_diff =
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required_money_by_input_count.at(selected_inputs_indices.size()) -
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required_money_by_input_count.at(selected_inputs_indices.size() - 1);
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CHECK_AND_ASSERT_THROW_MES(fee_diff >= 0,
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"make_single_transfer_input_selector: bug: fee is expected to be higher with fewer inputs");
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for (auto it = selected_inputs_indices.begin(); it != selected_inputs_indices.end(); ++it)
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{
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const CarrotPreSelectedInput &input_candidate = input_candidates[*it];
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if (input_candidate.core.amount < fee_diff)
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{
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MDEBUG("make_single_transfer_input_selector: dropping dusty input "
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<< input_candidate.core.key_image << " with amount " << input_candidate.core.amount
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<< ", which is less than the difference in fee of this transaction with it: " << fee_diff);
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selected_inputs_indices.erase(it);
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should_search_for_dust = true;
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break; // break out of inner `for` loop so we can recalculate `fee_diff`
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}
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}
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}
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// 16. Check the sum of input amounts is great enough
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const size_t num_selected = selected_inputs_indices.size();
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const boost::multiprecision::int128_t required_money = required_money_by_input_count.at(num_selected);
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boost::multiprecision::int128_t input_amount_sum = 0;
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for (const size_t idx : selected_inputs_indices)
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input_amount_sum += input_candidates[idx].core.amount;
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CHECK_AND_ASSERT_THROW_MES(input_amount_sum >= required_money,
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"make_single_transfer_input_selector: bug: input selection returned successful without enough funds");
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// 17. Collect selected inputs
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selected_inputs_out.clear();
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selected_inputs_out.reserve(num_selected);
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for (size_t selected_input_index : selected_inputs_indices)
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selected_inputs_out.push_back(input_candidates[selected_input_index].core);
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if (selected_input_indices_out != nullptr)
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*selected_input_indices_out = std::move(selected_inputs_indices);
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};
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}
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//-------------------------------------------------------------------------------------------------------------------
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namespace ispolicy
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{
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//-------------------------------------------------------------------------------------------------------------------
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std::vector<std::size_t> get_input_counts_in_preferred_order()
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{
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// 1 or 2 randomly, then
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// other ascending non-zero powers of 2, then
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// other ascending non-zero numbers
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//! @TODO: MRL discussion about 2 vs 1 default input count when 1 input can pay. If we default to 1, then that may
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// reveal more information about the amount, and reveals that one can't pay with 1 output when using 2. Vice versa,
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// if we default to 2, then that means that one only owns 1 output when using 1. It may be the most advantageous to
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// randomly switch between preferring 1 vs 2. See: https://lavalle.pl/planning/node437.html
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static_assert(CARROT_MAX_TX_INPUTS == FCMP_PLUS_PLUS_MAX_INPUTS, "inconsistent input count max limit");
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static_assert(CARROT_MIN_TX_INPUTS == 1 && CARROT_MAX_TX_INPUTS == 8,
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"refactor this function for different input count limits");
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const bool random_bit = 0 == (crypto::rand<uint8_t>() & 0x01);
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if (random_bit)
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return {2, 1, 4, 8, 3, 5, 6, 7};
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else
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return {1, 2, 4, 8, 3, 5, 6, 7};
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}
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//-------------------------------------------------------------------------------------------------------------------
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void select_two_inputs_prefer_oldest(const epee::span<const CarrotPreSelectedInput> input_candidates,
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const std::set<size_t> &selectable_inputs,
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const std::map<size_t, boost::multiprecision::int128_t> &required_money_by_input_count,
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|
std::set<size_t> &selected_inputs_indices_out)
|
|
{
|
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// calculate required money and fee diff from one to two inputs
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const boost::multiprecision::int128_t required_money = required_money_by_input_count.at(2);
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const rct::xmr_amount fee_diff = boost::numeric_cast<rct::xmr_amount>(required_money -
|
|
required_money_by_input_count.at(1));
|
|
|
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// copy selectable_inputs, excluding dust, then sort by ascending block index
|
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std::vector<size_t> selectable_inputs_by_bi;
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selectable_inputs_by_bi.reserve(selectable_inputs.size());
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for (size_t idx : selectable_inputs)
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if (input_candidates[idx].core.amount > fee_diff)
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selectable_inputs_by_bi.push_back(idx);
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stable_sort_indices_by_block_index(input_candidates, selectable_inputs_by_bi);
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|
|
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// then copy again and *stable* sort by amount
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std::vector<size_t> selectable_inputs_by_amount_bi = selectable_inputs_by_bi;
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stable_sort_indices_by_amount(input_candidates, selectable_inputs_by_amount_bi);
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|
|
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// for each input in ascending block index order...
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for (size_t low_bi_input : selectable_inputs_by_bi)
|
|
{
|
|
// calculate how much we need in a corresponding input to this one
|
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const rct::xmr_amount old_amount = input_candidates[low_bi_input].core.amount;
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const boost::multiprecision::int128_t required_money_in_other_128 = (required_money > old_amount)
|
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? (required_money - old_amount) : 0;
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if (required_money_in_other_128 >= std::numeric_limits<rct::xmr_amount>::max())
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continue;
|
|
const rct::xmr_amount required_money_in_other =
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|
boost::numeric_cast<rct::xmr_amount>(required_money_in_other_128);
|
|
|
|
// do a binary search for an input with at least that amount
|
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auto other_it = std::lower_bound(selectable_inputs_by_amount_bi.cbegin(),
|
|
selectable_inputs_by_amount_bi.cend(),
|
|
required_money_in_other,
|
|
[input_candidates](size_t selectable_index, rct::xmr_amount required_money_in_other) -> bool
|
|
{ return input_candidates[selectable_index].core.amount < required_money_in_other; });
|
|
|
|
// check that the iterator is in bounds and the complementary input isn't equal to the first
|
|
if (other_it == selectable_inputs_by_amount_bi.cend())
|
|
continue;
|
|
else if (*other_it == low_bi_input)
|
|
++other_it; // can't choose same input twice
|
|
|
|
if (other_it == selectable_inputs_by_amount_bi.cend())
|
|
continue;
|
|
|
|
// we found a match !
|
|
selected_inputs_indices_out = {low_bi_input, *other_it};
|
|
return;
|
|
}
|
|
}
|
|
//-------------------------------------------------------------------------------------------------------------------
|
|
void select_greedy_aging_fixed_count(const std::size_t fixed_n_inputs,
|
|
const epee::span<const CarrotPreSelectedInput> input_candidates,
|
|
const std::set<std::size_t> &selectable_inputs,
|
|
const std::map<size_t, boost::multiprecision::int128_t> &required_money_by_input_count,
|
|
std::set<std::size_t> &selected_inputs_indices_out)
|
|
{
|
|
selected_inputs_indices_out.clear();
|
|
|
|
CHECK_AND_ASSERT_MES(fixed_n_inputs,, "select_greedy_aging: fixed_n_inputs must be non-zero");
|
|
CHECK_AND_ASSERT_MES(fixed_n_inputs <= selectable_inputs.size(),,
|
|
"select_greedy_aging: not enough inputs: " << selectable_inputs.size() << '/' << fixed_n_inputs);
|
|
CHECK_AND_ASSERT_MES(required_money_by_input_count.count(fixed_n_inputs),,
|
|
"select_greedy_aging: input count " << fixed_n_inputs << "not allowed");
|
|
|
|
// Sort selectable inputs by amount
|
|
std::vector<std::size_t> selectable_inputs_by_amount(selectable_inputs.cbegin(), selectable_inputs.cend());
|
|
stable_sort_indices_by_amount(input_candidates, selectable_inputs_by_amount);
|
|
|
|
// Select highest amount inputs and collect ordered multi-map of block indices of current selected inputs
|
|
boost::multiprecision::uint128_t input_amount_sum = 0;
|
|
std::multimap<std::uint64_t, std::size_t> selected_indices_by_block_index;
|
|
for (size_t i = 0; i < fixed_n_inputs; ++i)
|
|
{
|
|
const std::size_t selectable_idx = selectable_inputs_by_amount.at(selectable_inputs_by_amount.size() - i - 1);
|
|
const CarrotPreSelectedInput &input = input_candidates[selectable_idx];
|
|
input_amount_sum += input.core.amount;
|
|
selected_inputs_indices_out.insert(selectable_idx);
|
|
selected_indices_by_block_index.emplace(input.block_index, selectable_idx);
|
|
}
|
|
|
|
// Check enough money
|
|
const boost::multiprecision::uint128_t required_money =
|
|
boost::numeric_cast<boost::multiprecision::uint128_t>(required_money_by_input_count.at(fixed_n_inputs));
|
|
if (input_amount_sum < required_money)
|
|
{
|
|
MDEBUG("not enough money in " << fixed_n_inputs << " inputs: " << cryptonote::print_money(input_amount_sum));
|
|
selected_inputs_indices_out.clear();
|
|
return;
|
|
}
|
|
|
|
// Right now, we have the highest amount inputs selected. Perform a greedy search to replace the newest inputs
|
|
// with the oldest possible input that still provides enough money
|
|
for (auto bi_it = selected_indices_by_block_index.rbegin(); bi_it != selected_indices_by_block_index.rend();)
|
|
{
|
|
std::uint64_t min_block_index = bi_it->first;
|
|
size_t input_of_min_block_index_input = bi_it->second;
|
|
const boost::multiprecision::uint128_t surplus = input_amount_sum - required_money;
|
|
const rct::xmr_amount currently_selected_amount = input_candidates[bi_it->second].core.amount;
|
|
const rct::xmr_amount lowest_replacement_amount = (currently_selected_amount > surplus)
|
|
? boost::numeric_cast<rct::xmr_amount>(currently_selected_amount - surplus) : 0;
|
|
const auto lower_amount_it = std::lower_bound(selectable_inputs_by_amount.cbegin(),
|
|
selectable_inputs_by_amount.cend(), lowest_replacement_amount);
|
|
for (auto amount_it = lower_amount_it; amount_it != selectable_inputs_by_amount.cend(); ++amount_it)
|
|
{
|
|
const std::size_t potential_replacement_idx = *amount_it;
|
|
if (selected_inputs_indices_out.count(potential_replacement_idx))
|
|
continue;
|
|
const CarrotPreSelectedInput &potential_replacement_input = input_candidates[potential_replacement_idx];
|
|
if (potential_replacement_input.block_index < min_block_index)
|
|
{
|
|
min_block_index = potential_replacement_input.block_index;
|
|
input_of_min_block_index_input = potential_replacement_idx;
|
|
}
|
|
}
|
|
|
|
if (input_of_min_block_index_input != bi_it->second) // i.e. found a replacement
|
|
{
|
|
selected_inputs_indices_out.erase(bi_it->second);
|
|
selected_inputs_indices_out.insert(input_of_min_block_index_input);
|
|
bi_it = tools::reverse_erase(selected_indices_by_block_index, bi_it);
|
|
selected_indices_by_block_index.emplace(min_block_index, input_of_min_block_index_input);
|
|
input_amount_sum -= currently_selected_amount;
|
|
input_amount_sum += input_candidates[input_of_min_block_index_input].core.amount;
|
|
CHECK_AND_ASSERT_THROW_MES(input_amount_sum >= required_money,
|
|
"select_greedy_aging: BUG: replaced an input with one of too low amount");
|
|
}
|
|
else // no replacement, go to next input
|
|
{
|
|
++bi_it;
|
|
}
|
|
}
|
|
}
|
|
//-------------------------------------------------------------------------------------------------------------------
|
|
void select_greedy_aging(const epee::span<const CarrotPreSelectedInput> input_candidates,
|
|
const std::set<std::size_t> &selectable_inputs,
|
|
const std::map<size_t, boost::multiprecision::int128_t> &required_money_by_input_count,
|
|
std::set<std::size_t> &selected_inputs_indices_out)
|
|
{
|
|
selected_inputs_indices_out.clear();
|
|
|
|
for (const std::size_t n_inputs : get_input_counts_in_preferred_order())
|
|
{
|
|
select_greedy_aging_fixed_count(n_inputs,
|
|
input_candidates,
|
|
selectable_inputs,
|
|
required_money_by_input_count,
|
|
selected_inputs_indices_out);
|
|
if (!selected_inputs_indices_out.empty())
|
|
return;
|
|
}
|
|
}
|
|
//-------------------------------------------------------------------------------------------------------------------
|
|
} //namespace ispolicy
|
|
} //namespace carrot
|