zstd_dec.h

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/* Copyright (c) 2019, 2024, Oracle and/or its affiliates.
 
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License, version 2.0,
   as published by the Free Software Foundation.
 
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   documentation.  The authors of MySQL hereby grant you an additional
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   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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#ifndef MYSQL_BINLOG_EVENT_COMPRESSION_ZSTD_DEC_H
#define MYSQL_BINLOG_EVENT_COMPRESSION_ZSTD_DEC_H
 
#define ZSTD_STATIC_LINKING_ONLY 1
#include <zstd.h>
 
#include "mysql/binlog/event/compression/decompressor.h"
#include "mysql/binlog/event/nodiscard.h"
#include "mysql/binlog/event/resource/memory_resource.h"  // Memory_resource
 
namespace mysql::binlog::event::compression {
 
/// Decompressor class that uses the ZSTD library.
class Zstd_dec : public Decompressor {
 public:
  using typename Decompressor::Char_t;
  using typename Decompressor::Grow_constraint_t;
  using typename Decompressor::Size_t;
  using Memory_resource_t = mysql::binlog::event::resource::Memory_resource;
  static constexpr type type_code = ZSTD;
 
  Zstd_dec(const Memory_resource_t &memory_resource = Memory_resource_t());
  ~Zstd_dec() override;
 
  Zstd_dec(const Zstd_dec &) = delete;
  Zstd_dec(const Zstd_dec &&) = delete;
  Zstd_dec &operator=(const Zstd_dec &) = delete;
  Zstd_dec &operator=(const Zstd_dec &&) = delete;
 
 private:
  /// @return ZSTD
  type do_get_type_code() const override;
 
  /// @copydoc Decompressor::do_reset
  void do_reset() override;
 
  /// @copydoc Decompressor::do_feed
  void do_feed(const Char_t *input_data, Size_t input_size) override;
 
  /// @copydoc Decompressor::do_decompress
  [[NODISCARD]] std::pair<Decompress_status, Size_t> do_decompress(
      Char_t *out, Size_t output_size) override;
 
  /// @copydoc Decompressor::do_get_grow_constraint_hint
  Grow_constraint_t do_get_grow_constraint_hint() const override;
 
  /// Deallocate the ZSTD decompression context.
  void destroy();
 
  /// ZSTD decompression context object.
  ZSTD_DStream *m_ctx{nullptr};
 
  /// ZSTD input buffer.
  ZSTD_inBuffer m_ibuf{nullptr, 0, 0};
 
  bool m_frame_boundary = false;
 
  /// Instrumented memory allocator object
  Memory_resource_t m_memory_resource;
 
  /// ZSTD memory allocator objects and functions
  ZSTD_customMem m_zstd_custom_mem;
  static void *zstd_mem_res_alloc(void *opaque, size_t size);
  static void zstd_mem_res_free(void *opaque, void *address);
};
 
}  // namespace mysql::binlog::event::compression
 
#endif  // MYSQL_BINLOG_EVENT_COMPRESSION_ZSTD_DEC_H