ceph/src/boost/libs/asio/include/boost/asio/detail/buffered_stream_storage.hpp

   1 //
   2 // detail/buffered_stream_storage.hpp
   3 // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   4 //
   5 // Copyright (c) 2003-2016 Christopher M. Kohlhoff (chris at kohlhoff dot com)
   6 //
   7 // Distributed under the Boost Software License, Version 1.0. (See accompanying
   8 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   9 //
  10
  11 #ifndef BOOST_ASIO_DETAIL_BUFFERED_STREAM_STORAGE_HPP
  12 #define BOOST_ASIO_DETAIL_BUFFERED_STREAM_STORAGE_HPP
  13
  14 #if defined(_MSC_VER) && (_MSC_VER >= 1200)
  15 # pragma once
  16 #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
  17
  18 #include <boost/asio/detail/config.hpp>
  19 #include <boost/asio/buffer.hpp>
  20 #include <boost/asio/detail/assert.hpp>
  21 #include <cstddef>
  22 #include <cstring>
  23 #include <vector>
  24
  25 #include <boost/asio/detail/push_options.hpp>
  26
  27 namespace boost {
  28 namespace asio {
  29 namespace detail {
  30
  31 class buffered_stream_storage
  32 {
  33 public:
  34   // The type of the bytes stored in the buffer.
  35   typedef unsigned char byte_type;
  36
  37   // The type used for offsets into the buffer.
  38   typedef std::size_t size_type;
  39
  40   // Constructor.
  41   explicit buffered_stream_storage(std::size_t buffer_capacity)
  42     : begin_offset_(0),
  43       end_offset_(0),
  44       buffer_(buffer_capacity)
  45   {
  46   }
  47
  48   /// Clear the buffer.
  49   void clear()
  50   {
  51     begin_offset_ = 0;
  52     end_offset_ = 0;
  53   }
  54
  55   // Return a pointer to the beginning of the unread data.
  56   mutable_buffer data()
  57   {
  58     return boost::asio::buffer(buffer_) + begin_offset_;
  59   }
  60
  61   // Return a pointer to the beginning of the unread data.
  62   const_buffer data() const
  63   {
  64     return boost::asio::buffer(buffer_) + begin_offset_;
  65   }
  66
  67   // Is there no unread data in the buffer.
  68   bool empty() const
  69   {
  70     return begin_offset_ == end_offset_;
  71   }
  72
  73   // Return the amount of unread data the is in the buffer.
  74   size_type size() const
  75   {
  76     return end_offset_ - begin_offset_;
  77   }
  78
  79   // Resize the buffer to the specified length.
  80   void resize(size_type length)
  81   {
  82     BOOST_ASIO_ASSERT(length <= capacity());
  83     if (begin_offset_ + length <= capacity())
  84     {
  85       end_offset_ = begin_offset_ + length;
  86     }
  87     else
  88     {
  89       using namespace std; // For memmove.
  90       memmove(&buffer_[0], &buffer_[0] + begin_offset_, size());
  91       end_offset_ = length;
  92       begin_offset_ = 0;
  93     }
  94   }
  95
  96   // Return the maximum size for data in the buffer.
  97   size_type capacity() const
  98   {
  99     return buffer_.size();
 100   }
 101
 102   // Consume multiple bytes from the beginning of the buffer.
 103   void consume(size_type count)
 104   {
 105     BOOST_ASIO_ASSERT(begin_offset_ + count <= end_offset_);
 106     begin_offset_ += count;
 107     if (empty())
 108       clear();
 109   }
 110
 111 private:
 112   // The offset to the beginning of the unread data.
 113   size_type begin_offset_;
 114
 115   // The offset to the end of the unread data.
 116   size_type end_offset_;
 117
 118   // The data in the buffer.
 119   std::vector<byte_type> buffer_;
 120 };
 121
 122 } // namespace detail
 123 } // namespace asio
 124 } // namespace boost
 125
 126 #include <boost/asio/detail/pop_options.hpp>
 127
 128 #endif // BOOST_ASIO_DETAIL_BUFFERED_STREAM_STORAGE_HPP