src/util/regex/regex-matcher.cpp

/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/**
 * Copyright (c) 2013-2015 Regents of the University of California.
 *
 * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
 *
 * ndn-cxx library is free software: you can redistribute it and/or modify it under the
 * terms of the GNU Lesser General Public License as published by the Free Software
 * Foundation, either version 3 of the License, or (at your option) any later version.
 *
 * ndn-cxx library is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
 * PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more details.
 *
 * You should have received copies of the GNU General Public License and GNU Lesser
 * General Public License along with ndn-cxx, e.g., in COPYING.md file.  If not, see
 * <http://www.gnu.org/licenses/>.
 *
 * See AUTHORS.md for complete list of ndn-cxx authors and contributors.
 */

#include "regex-matcher.hpp"

namespace ndn {

RegexMatcher::RegexMatcher(const std::string& expr,
                           const RegexExprType& type,
                           shared_ptr<RegexBackrefManager> backrefManager)
  : m_expr(expr)
  , m_type(type)
  , m_backrefManager(backrefManager)
{
  if (!static_cast<bool>(m_backrefManager))
    m_backrefManager = make_shared<RegexBackrefManager>();
}

RegexMatcher::~RegexMatcher()
{
}

bool
RegexMatcher::match(const Name& name, size_t offset, size_t len)
{
  bool result = false;

  m_matchResult.clear();

  if (recursiveMatch(0, name, offset, len)) {
      for (size_t i = offset; i < offset + len ; i++)
        m_matchResult.push_back(name.get(i));
      result = true;
  }
  else {
    result = false;
  }

  return result;
}

bool
RegexMatcher::recursiveMatch(size_t matcherNo, const Name& name, size_t offset, size_t len)
{
  ssize_t tried = len;

  if (matcherNo >= m_matchers.size())
    return (len == 0);

  shared_ptr<RegexMatcher> matcher = m_matchers[matcherNo];

  while (tried >= 0) {
    if (matcher->match(name, offset, tried) &&
        recursiveMatch(matcherNo + 1, name, offset + tried, len - tried))
      return true;
    tried--;
  }

  return false;
}

} // namespace ndn