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       1              : //
       2              : // Copyright (c) 2021 Vinnie Falco (vinnie.falco@gmail.com)
       3              : // Copyright (c) 2024 Christian Mazakas
       4              : //
       5              : // Distributed under the Boost Software License, Version 1.0. (See accompanying
       6              : // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
       7              : //
       8              : // Official repository: https://github.com/cppalliance/http_proto
       9              : //
      10              : 
      11              : #ifndef BOOST_HTTP_PROTO_SERVICE_ZLIB_SERVICE_HPP
      12              : #define BOOST_HTTP_PROTO_SERVICE_ZLIB_SERVICE_HPP
      13              : 
      14              : #include <boost/http_proto/detail/config.hpp>
      15              : #include <boost/http_proto/context.hpp>
      16              : #include <boost/http_proto/filter.hpp>
      17              : #include <boost/http_proto/service/service.hpp>
      18              : #include <boost/http_proto/detail/workspace.hpp>
      19              : 
      20              : namespace boost {
      21              : namespace http_proto {
      22              : namespace zlib {
      23              : 
      24              : struct decoder_config
      25              : {
      26              :     unsigned max_window_bits = 15;
      27              :     unsigned mem_level = 8;
      28              : };
      29              : 
      30              : //------------------------------------------------
      31              : 
      32              : constexpr
      33              : inline
      34              : std::size_t
      35           24 : encoding_size_hint(decoder_config cfg = {}) noexcept
      36              : {
      37              :     // from: https://www.zlib.net/zlib_tech.html
      38              :     //
      39              :     // Memory Footprint
      40              :     //
      41              :     // zlib's memory footprint can also be specified fairly
      42              :     // precisely. It is larger for compression than for
      43              :     // decompression, and the exact requirements depend on
      44              :     // how the library was compiled.
      45              :     //
      46              :     // The memory requirements for compression depend on two
      47              :     // parameters, windowBits and memLevel:
      48              :     //     deflate memory usage (bytes) = (1 << (windowBits+2)) + (1 << (memLevel+9)) + 6 KB
      49              :     return
      50           24 :         (1 << (cfg.max_window_bits + 2)) +
      51           24 :         (1 << (cfg.mem_level + 9)) +
      52           24 :         (6 * 1024);
      53              : }
      54              : 
      55              : void BOOST_HTTP_PROTO_ZLIB_DECL
      56              : install_deflate_encoder(context& ctx);
      57              : 
      58              : } // zlib
      59              : } // http_proto
      60              : } // boost
      61              : 
      62              : #endif