Source/cm_codecvt.hxx

   1 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
   2    file Copyright.txt or https://cmake.org/licensing for details.  */
   3 #pragma once
   4
   5 #include "cmConfigure.h" // IWYU pragma: keep
   6
   7 #include <cwchar>
   8 #include <locale>
   9
  10 enum class codecvt_Encoding;
  11
  12 class codecvt : public std::codecvt<char, char, mbstate_t>
  13 {
  14 public:
  15 #ifndef CMAKE_BOOTSTRAP
  16
  17   codecvt(codecvt_Encoding e);
  18
  19 protected:
  20   ~codecvt() override;
  21   bool do_always_noconv() const noexcept override;
  22   result do_out(mbstate_t& state, const char* from, const char* from_end,
  23                 const char*& from_next, char* to, char* to_end,
  24                 char*& to_next) const override;
  25   result do_unshift(mbstate_t& state, char* to, char*,
  26                     char*& to_next) const override;
  27   int do_max_length() const noexcept override;
  28   int do_encoding() const noexcept override;
  29
  30 private:
  31   // The mbstate_t argument to do_out and do_unshift is responsible
  32   // for storing state between calls.  We cannot control the type
  33   // since we want to imbue on standard streams.  However, we do
  34   // know that it is a trivial type.  Define our own type to overlay
  35   // on it safely with no alignment requirements.
  36   struct State
  37   {
  38     // Buffer bytes we have consumed from a partial codepoint.
  39     char partial[3];
  40
  41     // Number of bytes we have buffered from a partial codepoint.
  42     unsigned char buffered : 4;
  43
  44     // Size of the current codepoint in bytes.
  45     unsigned char size : 4;
  46   };
  47
  48   bool m_noconv;
  49 #  if defined(_WIN32)
  50   unsigned int m_codepage;
  51   result Decode(mbstate_t& state, int need, const char*& from_next,
  52                 char*& to_next, char* to_end) const;
  53   result DecodePartial(mbstate_t& state, char*& to_next, char* to_end) const;
  54   void BufferPartial(mbstate_t& state, int need, const char*& from_next) const;
  55 #  endif
  56
  57 #endif
  58 };