ceph/src/boost/boost/beast/websocket/detail/utf8_checker.hpp

   1 //
   2 // Copyright (c) 2016-2019 Vinnie Falco (vinnie dot falco at gmail dot com)
   3 //
   4 // Distributed under the Boost Software License, Version 1.0. (See accompanying
   5 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   6 //
   7 // Official repository: https://github.com/boostorg/beast
   8 //
   9
  10 #ifndef BOOST_BEAST_WEBSOCKET_DETAIL_UTF8_CHECKER_HPP
  11 #define BOOST_BEAST_WEBSOCKET_DETAIL_UTF8_CHECKER_HPP
  12
  13 #include <boost/beast/core/buffers_range.hpp>
  14 #include <boost/asio/buffer.hpp>
  15
  16 #include <cstdint>
  17
  18 namespace boost {
  19 namespace beast {
  20 namespace websocket {
  21 namespace detail {
  22
  23 /** A UTF8 validator.
  24
  25     This validator can be used to check if a buffer containing UTF8 text is
  26     valid. The write function may be called incrementally with segmented UTF8
  27     sequences. The finish function determines if all processed text is valid.
  28 */
  29 class utf8_checker
  30 {
  31     std::size_t need_ = 0;  // chars we need to finish the code point
  32     std::uint8_t* p_ = cp_; // current position in temp buffer
  33     std::uint8_t cp_[4];    // a temp buffer for the code point
  34
  35 public:
  36     /** Prepare to process text as valid utf8
  37     */
  38     BOOST_BEAST_DECL
  39     void
  40     reset();
  41
  42     /** Check that all processed text is valid utf8
  43     */
  44     BOOST_BEAST_DECL
  45     bool
  46     finish();
  47
  48     /** Check if text is valid UTF8
  49
  50         @return `true` if the text is valid utf8 or false otherwise.
  51     */
  52     BOOST_BEAST_DECL
  53     bool
  54     write(std::uint8_t const* in, std::size_t size);
  55
  56     /** Check if text is valid UTF8
  57
  58         @return `true` if the text is valid utf8 or false otherwise.
  59     */
  60     template<class ConstBufferSequence>
  61     bool
  62     write(ConstBufferSequence const& bs);
  63 };
  64
  65
  66 template<class ConstBufferSequence>
  67 bool
  68 utf8_checker::
  69 write(ConstBufferSequence const& buffers)
  70 {
  71     static_assert(
  72         net::is_const_buffer_sequence<ConstBufferSequence>::value,
  73         "ConstBufferSequence type requirements not met");
  74     for(auto b : beast::buffers_range_ref(buffers))
  75         if(! write(static_cast<
  76             std::uint8_t const*>(b.data()),
  77                 b.size()))
  78             return false;
  79     return true;
  80 }
  81
  82
  83 BOOST_BEAST_DECL
  84 bool
  85 check_utf8(char const* p, std::size_t n);
  86
  87 } // detail
  88 } // websocket
  89 } // beast
  90 } // boost
  91
  92 #if BOOST_BEAST_HEADER_ONLY
  93 #include <boost/beast/websocket/detail/utf8_checker.ipp>
  94 #endif
  95
  96 #endif