text: // Copyright (c) 2019, The Monero Project
  // 
  // All rights reserved.
  // 
  // Redistribution and use in source and binary forms, with or without modification, are
  // permitted provided that the following conditions are met:
  // 
  // 1. Redistributions of source code must retain the above copyright notice, this list of
  //    conditions and the following disclaimer.
  // 
  // 2. Redistributions in binary form must reproduce the above copyright notice, this list
  //    of conditions and the following disclaimer in the documentation and/or other
  //    materials provided with the distribution.
  // 
  // 3. Neither the name of the copyright holder nor the names of its contributors may be
  //    used to endorse or promote products derived from this software without specific
  //    prior written permission.
  // 
  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
  // EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  // MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
  // THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  // PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  // INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  // STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
  // THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
  #include <stdint.h>
  #include <vector>
  #include "cryptonote_basic/cryptonote_basic_impl.h"
  #include "cryptonote_basic/cryptonote_format_utils.h"
  #include "blockchain.h"
  #include "tx_sanity_check.h"
  
  #undef VAIZON_DEFAULT_LOG_CATEGORY
  #define VAIZON_DEFAULT_LOG_CATEGORY "verify"
  
  namespace cryptonote
  {
  
  bool tx_sanity_check(Blockchain &blockchain, const cryptonote::blobdata &tx_blob)
  {
    cryptonote::transaction tx;
  
    if (!cryptonote::parse_and_validate_tx_from_blob(tx_blob, tx))
    {
      MERROR("Failed to parse transaction");
      return false;
    }
  
    if (cryptonote::is_coinbase(tx))
    {
      MERROR("Transaction is coinbase");
      return false;
    }
    std::set<uint64_t> rct_indices;
    size_t n_indices = 0;
  
    for (const auto &txin : tx.vin)
    {
      if (txin.type() != typeid(cryptonote::txin_to_key))
        continue;
      const cryptonote::txin_to_key &in_to_key = boost::get<cryptonote::txin_to_key>(txin);
      if (in_to_key.amount != 0)
        continue;
      const std::vector<uint64_t> absolute = cryptonote::relative_output_offsets_to_absolute(in_to_key.key_offsets);
      for (uint64_t offset: absolute)
        rct_indices.insert(offset);
      n_indices += in_to_key.key_offsets.size();
    }
  
    if (n_indices <= 10)
    {
      MERROR("n_indices is only " << n_indices);
      return true;
    }
  
    uint64_t n_available = blockchain.get_num_mature_outputs(0);
    if (n_available < 10000)
      return true;
  
    if (rct_indices.size() < n_indices * 8 / 10)
    {
      MERROR("unique indices is only " << rct_indices.size() << "/" << n_indices);
      return false;
    }
  
    std::vector<uint64_t> offsets(rct_indices.begin(), rct_indices.end());
    uint64_t median = epee::misc_utils::median(offsets);
    if (median < n_available * 6 / 10)
    {
      MERROR("median is " << median << "/" << n_available);
      return false;
    }
  
    return true;
  }
  
  }
  