databus.hpp

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// === AUDIT STATUS ===
// internal:    { status: not started, auditors: [], date: YYYY-MM-DD }
// external_1:  { status: not started, auditors: [], date: YYYY-MM-DD }
// external_2:  { status: not started, auditors: [], date: YYYY-MM-DD }
// =====================
 
#pragma once
 
#include "barretenberg/common/assert.hpp"
#include "barretenberg/ecc/curves/bn254/fr.hpp"
#include "barretenberg/public_input_component/public_component_key.hpp"
#include <cstdint>
namespace bb {
 
// We assume all kernels have space for two return data commitments on their public inputs
constexpr uint32_t NUM_DATABUS_COMMITMENTS = 2;
constexpr uint32_t PROPAGATED_DATABUS_COMMITMENT_SIZE = 8;
constexpr uint32_t PROPAGATED_DATABUS_COMMITMENTS_SIZE = PROPAGATED_DATABUS_COMMITMENT_SIZE * NUM_DATABUS_COMMITMENTS;
 
struct BusVector {
 
    // A default value added to every databus column to avoid the point at infinity commitment and to ensure the
    // validity of the databus commitment consistency checks. Note: in principle we could allow point at infinity
    // default commitment but there is precedent for avoiding this by default.
    static constexpr bb::fr DEFAULT_VALUE = 25;
 
    void append(const uint32_t& idx)
    {
        data.emplace_back(idx);
        read_counts.emplace_back(0);
    }
 
    size_t size() const { return data.size(); }
 
    const uint32_t& operator[](size_t idx) const
    {
        BB_ASSERT_LT(idx, size());
        return data[idx];
    }
 
    const uint32_t& get_read_count(size_t idx) const
    {
        BB_ASSERT_LT(idx, read_counts.size());
        return read_counts[idx];
    }
 
    void increment_read_count(size_t idx)
    {
        BB_ASSERT_LT(idx, read_counts.size());
        read_counts[idx]++;
    }
 
  private:
    std::vector<uint32_t> read_counts; // count of reads at each index into data
    std::vector<uint32_t> data;        // variable indices corresponding to data in this bus vector
};
 
using DataBus = std::array<BusVector, 3>;
enum class BusId { CALLDATA, SECONDARY_CALLDATA, RETURNDATA };
 
} // namespace bb