read_until.ipp

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//
// read_until.ipp
// ~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2008 Christopher M. Kohlhoff (chris at kohlhoff dot com)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//

#ifndef BOOST_ASIO_READ_UNTIL_IPP
#define BOOST_ASIO_READ_UNTIL_IPP

#if defined(_MSC_VER) && (_MSC_VER >= 1200)
# pragma once
#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)

#include <boost/asio/detail/push_options.hpp>

#include <boost/asio/detail/push_options.hpp>
#include <algorithm>
#include <limits>
#include <string>
#include <utility>
#include <boost/asio/detail/pop_options.hpp>

#include <boost/asio/buffer.hpp>
#include <boost/asio/buffers_iterator.hpp>
#include <boost/asio/detail/bind_handler.hpp>
#include <boost/asio/detail/handler_alloc_helpers.hpp>
#include <boost/asio/detail/handler_invoke_helpers.hpp>
#include <boost/asio/detail/throw_error.hpp>

namespace boost {
namespace asio {

template <typename SyncReadStream, typename Allocator>
inline std::size_t read_until(SyncReadStream& s,
    boost::asio::basic_streambuf<Allocator>& b, char delim)
{
  boost::system::error_code ec;
  std::size_t bytes_transferred = read_until(s, b, delim, ec);
  boost::asio::detail::throw_error(ec);
  return bytes_transferred;
}

template <typename SyncReadStream, typename Allocator>
std::size_t read_until(SyncReadStream& s,
    boost::asio::basic_streambuf<Allocator>& b, char delim,
    boost::system::error_code& ec)
{
  std::size_t next_search_start = 0;
  for (;;)
  {
    // Determine the range of the data to be searched.
    typedef typename boost::asio::basic_streambuf<
      Allocator>::const_buffers_type const_buffers_type;
    typedef boost::asio::buffers_iterator<const_buffers_type> iterator;
    const_buffers_type buffers = b.data();
    iterator begin = iterator::begin(buffers);
    iterator start = begin + next_search_start;
    iterator end = iterator::end(buffers);

    // Look for a match.
    iterator iter = std::find(start, end, delim);
    if (iter != end)
    {
      // Found a match. We're done.
      ec = boost::system::error_code();
      return iter - begin + 1;
    }
    else
    {
      // No match. Next search can start with the new data.
      next_search_start = end - begin;
    }

    // Check if buffer is full.
    if (b.size() == b.max_size())
    {
      ec = error::not_found;
      return 0;
    }

    // Need more data.
    std::size_t bytes_available =
      std::min<std::size_t>(512, b.max_size() - b.size());
    b.commit(s.read_some(b.prepare(bytes_available), ec));
    if (ec)
      return 0;
  }
}

template <typename SyncReadStream, typename Allocator>
inline std::size_t read_until(SyncReadStream& s,
    boost::asio::basic_streambuf<Allocator>& b, const std::string& delim)
{
  boost::system::error_code ec;
  std::size_t bytes_transferred = read_until(s, b, delim, ec);
  boost::asio::detail::throw_error(ec);
  return bytes_transferred;
}

namespace detail
{
  // Algorithm that finds a subsequence of equal values in a sequence. Returns
  // (iterator,true) if a full match was found, in which case the iterator
  // points to the beginning of the match. Returns (iterator,false) if a
  // partial match was found at the end of the first sequence, in which case
  // the iterator points to the beginning of the partial match. Returns
  // (last1,false) if no full or partial match was found.
  template <typename Iterator1, typename Iterator2>
  std::pair<Iterator1, bool> partial_search(
      Iterator1 first1, Iterator1 last1, Iterator2 first2, Iterator2 last2)
  {
    for (Iterator1 iter1 = first1; iter1 != last1; ++iter1)
    {
      Iterator1 test_iter1 = iter1;
      Iterator2 test_iter2 = first2;
      for (;; ++test_iter1, ++test_iter2)
      {
        if (test_iter2 == last2)
          return std::make_pair(iter1, true);
        if (test_iter1 == last1)
        {
          if (test_iter2 != first2)
            return std::make_pair(iter1, false);
          else
            break;
        }
        if (*test_iter1 != *test_iter2)
          break;
      }
    }
    return std::make_pair(last1, false);
  }
} // namespace detail

template <typename SyncReadStream, typename Allocator>
std::size_t read_until(SyncReadStream& s,
    boost::asio::basic_streambuf<Allocator>& b, const std::string& delim,
    boost::system::error_code& ec)
{
  std::size_t next_search_start = 0;
  for (;;)
  {
    // Determine the range of the data to be searched.
    typedef typename boost::asio::basic_streambuf<
      Allocator>::const_buffers_type const_buffers_type;
    typedef boost::asio::buffers_iterator<const_buffers_type> iterator;
    const_buffers_type buffers = b.data();
    iterator begin = iterator::begin(buffers);
    iterator start = begin + next_search_start;
    iterator end = iterator::end(buffers);

    // Look for a match.
    std::pair<iterator, bool> result = boost::asio::detail::partial_search(
        start, end, delim.begin(), delim.end());
    if (result.first != end)
    {
      if (result.second)
      {
        // Full match. We're done.
        ec = boost::system::error_code();
        return result.first - begin + delim.length();
      }
      else
      {
        // Partial match. Next search needs to start from beginning of match.
        next_search_start = result.first - begin;
      }
    }
    else
    {
      // No match. Next search can start with the new data.
      next_search_start = end - begin;
    }

    // Check if buffer is full.
    if (b.size() == b.max_size())
    {
      ec = error::not_found;
      return 0;
    }

    // Need more data.
    std::size_t bytes_available =
      std::min<std::size_t>(512, b.max_size() - b.size());
    b.commit(s.read_some(b.prepare(bytes_available), ec));
    if (ec)
      return 0;
  }
}

template <typename SyncReadStream, typename Allocator>
inline std::size_t read_until(SyncReadStream& s,
    boost::asio::basic_streambuf<Allocator>& b, const boost::regex& expr)
{
  boost::system::error_code ec;
  std::size_t bytes_transferred = read_until(s, b, expr, ec);
  boost::asio::detail::throw_error(ec);
  return bytes_transferred;
}

template <typename SyncReadStream, typename Allocator>
std::size_t read_until(SyncReadStream& s,
    boost::asio::basic_streambuf<Allocator>& b, const boost::regex& expr,
    boost::system::error_code& ec)
{
  std::size_t next_search_start = 0;
  for (;;)
  {
    // Determine the range of the data to be searched.
    typedef typename boost::asio::basic_streambuf<
      Allocator>::const_buffers_type const_buffers_type;
    typedef boost::asio::buffers_iterator<const_buffers_type> iterator;
    const_buffers_type buffers = b.data();
    iterator begin = iterator::begin(buffers);
    iterator start = begin + next_search_start;
    iterator end = iterator::end(buffers);

    // Look for a match.
    boost::match_results<iterator> match_results;
    if (boost::regex_search(start, end, match_results, expr,
          boost::match_default | boost::match_partial))
    {
      if (match_results[0].matched)
      {
        // Full match. We're done.
        ec = boost::system::error_code();
        return match_results[0].second - begin;
      }
      else
      {
        // Partial match. Next search needs to start from beginning of match.
        next_search_start = match_results[0].first - begin;
      }
    }
    else
    {
      // No match. Next search can start with the new data.
      next_search_start = end - begin;
    }

    // Check if buffer is full.
    if (b.size() == b.max_size())
    {
      ec = error::not_found;
      return 0;
    }

    // Need more data.
    std::size_t bytes_available =
      std::min<std::size_t>(512, b.max_size() - b.size());
    b.commit(s.read_some(b.prepare(bytes_available), ec));
    if (ec)
      return 0;
  }
}

template <typename SyncReadStream, typename Allocator, typename MatchCondition>
std::size_t read_until(SyncReadStream& s,
    boost::asio::basic_streambuf<Allocator>& b,
    MatchCondition match_condition, boost::system::error_code& ec,
    typename boost::enable_if<is_match_condition<MatchCondition> >::type*)
{
  std::size_t next_search_start = 0;
  for (;;)
  {
    // Determine the range of the data to be searched.
    typedef typename boost::asio::basic_streambuf<
      Allocator>::const_buffers_type const_buffers_type;
    typedef boost::asio::buffers_iterator<const_buffers_type> iterator;
    const_buffers_type buffers = b.data();
    iterator begin = iterator::begin(buffers);
    iterator start = begin + next_search_start;
    iterator end = iterator::end(buffers);

    // Look for a match.
    std::pair<iterator, bool> result = match_condition(start, end);
    if (result.second)
    {
      // Full match. We're done.
      ec = boost::system::error_code();
      return result.first - begin;
    }
    else if (result.first != end)
    {
      // Partial match. Next search needs to start from beginning of match.
      next_search_start = result.first - begin;
    }
    else
    {
      // No match. Next search can start with the new data.
      next_search_start = end - begin;
    }

    // Check if buffer is full.
    if (b.size() == b.max_size())
    {
      ec = error::not_found;
      return 0;
    }

    // Need more data.
    std::size_t bytes_available =
      std::min<std::size_t>(512, b.max_size() - b.size());
    b.commit(s.read_some(b.prepare(bytes_available), ec));
    if (ec)
      return 0;
  }
}

template <typename SyncReadStream, typename Allocator, typename MatchCondition>
inline std::size_t read_until(SyncReadStream& s,
    boost::asio::basic_streambuf<Allocator>& b, MatchCondition match_condition,
    typename boost::enable_if<is_match_condition<MatchCondition> >::type*)
{
  boost::system::error_code ec;
  std::size_t bytes_transferred = read_until(s, b, match_condition, ec);
  boost::asio::detail::throw_error(ec);
  return bytes_transferred;
}

namespace detail
{
  template <typename AsyncReadStream, typename Allocator, typename ReadHandler>
  class read_until_delim_handler
  {
  public: