Line data    Source code

       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/context.hpp>
      15              : #include <boost/http_proto/detail/config.hpp>
      16              : #include <boost/http_proto/detail/workspace.hpp>
      17              : #include <boost/http_proto/service/service.hpp>
      18              : 
      19              : #include <boost/buffers/const_buffer.hpp>
      20              : #include <boost/buffers/mutable_buffer.hpp>
      21              : 
      22              : namespace boost {
      23              : namespace http_proto {
      24              : namespace zlib {
      25              : 
      26              : struct decoder_config
      27              : {
      28              :     unsigned max_window_bits = 15;
      29              :     unsigned mem_level = 8;
      30              : };
      31              : 
      32              : //------------------------------------------------
      33              : 
      34              : constexpr
      35              : inline
      36              : std::size_t
      37           24 : encoding_size_hint(decoder_config cfg = {}) noexcept
      38              : {
      39              :     // from: https://www.zlib.net/zlib_tech.html
      40              :     //
      41              :     // Memory Footprint
      42              :     //
      43              :     // zlib's memory footprint can also be specified fairly
      44              :     // precisely. It is larger for compression than for
      45              :     // decompression, and the exact requirements depend on
      46              :     // how the library was compiled.
      47              :     //
      48              :     // The memory requirements for compression depend on two
      49              :     // parameters, windowBits and memLevel:
      50              :     //     deflate memory usage (bytes) = (1 << (windowBits+2)) + (1 << (memLevel+9)) + 6 KB
      51              :     return
      52           24 :         (1 << (cfg.max_window_bits + 2)) +
      53           24 :         (1 << (cfg.mem_level + 9)) +
      54           24 :         (6 * 1024);
      55              : }
      56              : 
      57              : struct BOOST_HTTP_PROTO_ZLIB_DECL
      58              :     service
      59              :     : http_proto::service
      60              : {
      61              :     struct stream
      62              :     {
      63              :         enum class flush
      64              :         {
      65              :             none,
      66              :             partial,
      67              :             sync,
      68              :             full,
      69              :             finish,
      70              :             block,
      71              :             trees
      72              :         };
      73              : 
      74              :         struct results
      75              :         {
      76              :             std::size_t out_bytes;
      77              :             std::size_t in_bytes;
      78              :             system::error_code ec;
      79              :             bool finished;
      80              :         };
      81              : 
      82              :         virtual results
      83              :         write(
      84              :             buffers::mutable_buffer out,
      85              :             buffers::const_buffer in,
      86              :             flush) noexcept = 0;
      87              :     };
      88              : 
      89              :     virtual
      90              :     std::size_t
      91              :     space_needed() const noexcept = 0;
      92              : 
      93              :     virtual stream&
      94              :     make_deflator(
      95              :         http_proto::detail::workspace& ws,
      96              :         int level,
      97              :         int window_bits,
      98              :         int mem_level) const = 0;
      99              : 
     100              :     virtual stream&
     101              :     make_inflator(
     102              :         http_proto::detail::workspace& ws,
     103              :         int window_bits) const = 0;
     104              : };
     105              : 
     106              : void BOOST_HTTP_PROTO_ZLIB_DECL
     107              : install_service(context& ctx);
     108              : 
     109              : } // zlib
     110              : } // http_proto
     111              : } // boost
     112              : 
     113              : #endif