/* Copyright 2017 - 2022 R. Thomas
 * Copyright 2017 - 2022 Quarkslab
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#ifndef LIEF_ELF_GNU_HASH_H_
#define LIEF_ELF_GNU_HASH_H_

#include <vector>
#include <iostream>

#include "LIEF/Object.hpp"
#include "LIEF/visibility.h"

namespace LIEF {
namespace ELF {

class Parser;
class Builder;
class Binary;

//! Class which provides a view over the GNU Hash implementation.
//! Most of the fields are read-only since the values
//! are re-computed by the LIEF::ELF::Builder.
class LIEF_API GnuHash : public Object {

  friend class Parser;
  friend class Builder;
  friend class Binary;

  public:
  GnuHash();
  GnuHash(uint32_t symbol_idx, uint32_t shift2,
          std::vector<uint64_t> bloom_filters, std::vector<uint32_t> buckets,
          std::vector<uint32_t> hash_values = {});


  GnuHash& operator=(const GnuHash& copy);
  GnuHash(const GnuHash& copy);

  GnuHash(GnuHash&&);
  GnuHash& operator=(GnuHash&&);

  ~GnuHash() override;

  //! Return the number of buckets
  //! @see GnuHash::buckets
  uint32_t nb_buckets() const;

  //! Index of the first symbol in the dynamic
  //! symbols table which accessible with the hash table
  uint32_t symbol_index() const;

  //! Shift count used in the bloom filter
  uint32_t shift2() const;

  //! Number of bloom filters used.
  //! It must be a power of 2
  uint32_t maskwords() const;

  //! Bloom filters
  const std::vector<uint64_t>& bloom_filters() const;

  //! Hash buckets
  const std::vector<uint32_t>& buckets() const;

  //! Hash values
  const std::vector<uint32_t>& hash_values() const;

  //! Check if the given hash passes the bloom filter
  bool check_bloom_filter(uint32_t hash) const;

  //! Check if the given hash passes the bucket filter
  bool check_bucket(uint32_t hash) const;

  //! Check if the symbol *probably* exists. If
  //! the returned value is ``false`` you can assume at ``100%`` that
  //! the symbol with the given name doesn't exist. If ``true``, you can't
  //! do any assumption
  bool check(const std::string& symbol_name) const;

  //! Check if the symbol associated with the given hash *probably* exists. If
  //! the returned value is ``false`` you can assume at ``100%`` that
  //! the symbol doesn't exists. If ``true`` you can't
  //! do any assumption
  bool check(uint32_t hash) const;

  bool operator==(const GnuHash& rhs) const;
  bool operator!=(const GnuHash& rhs) const;

  void accept(Visitor& visitor) const override;

  LIEF_API friend std::ostream& operator<<(std::ostream& os, const GnuHash& gnuhash);

  private:
  uint32_t symbol_index_ = 0;
  uint32_t shift2_       = 0;

  std::vector<uint64_t> bloom_filters_;
  std::vector<uint32_t> buckets_;
  std::vector<uint32_t> hash_values_;

  size_t c_ = 0;
};


} // namepsace ELF
} // namespace LIEF

#endif