PropertiesToString.cc

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/*
 * Copyright 2006-2009 Savarese Software Research Corporation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     https://www.savarese.com/software/ApacheLicense-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <ssrc/wispers/utility/PropertiesToString.h>

#include <cstring>
#include <cctype>

namespace {
  const char * const lua_escape_chars = "\a\b\t\n\v\f\r\"\\";
  const char lua_escaped_chars[] = {
    'a', 'b', 't', 'n', 'v', 'f', 'r', '"', '\\'
  };

  enum { Assignment, OpenQuotedKey, CloseQuotedKey,
         OpenArray, CloseArray, ValueKey, NumTokens };

  const char * const OutputToken[2][NumTokens] = {
    { "=", "[\"",  "\"]=", "{", "}", "_value=" },
    { ":", "\"", "\":", "[", "]", "_value:" }
  };
}

__BEGIN_NS_SSRC_WSPR_UTILITY

void escape_lua(string & result,
                const char *text, const unsigned int text_size)
{
  const char * const end = text + text_size;
  const char *pos;
  result.reserve(2*text_size);

  while(text < end && (pos = std::strpbrk(text, lua_escape_chars)) != 0) {
    result.append(text, (pos - text)).append(1, '\\')
      .append(1, lua_escaped_chars[std::strchr(lua_escape_chars, *pos) - lua_escape_chars]);
    text = pos + 1;
  }

  if(text < end) {
    result.append(text, (end - text));
  }
}

void PropertiesToString::operator()(const primitive_property_vector & v) const {
  _out << _token[OpenArray];

  for(primitive_property_vector::const_iterator && it = v.begin(),
        && end = v.end(); it != end; )
  {
    boost::apply_visitor(*this, *it);
    ++it;
    if(it != end) {
      _out << ",";
    }
  }

  _out << _token[CloseArray];
}

void PropertiesToString::operator()(const property_vector & v) const {
  _out << _token[OpenArray];

  for(property_vector::const_iterator && it = v.begin(), && end = v.end();
      it != end; )
  {
    PropertiesToString::operator()(*it);
    ++it;
    if(it != end) {
      _out << ",";
    }
  }

  _out << _token[CloseArray];
}

void PropertiesToString::enter(const std::string & key,
                               const Properties *props,
                               const bool is_last_child) const
{
  const property_type *v = props->value();

  // Always quote keys because 1. required by JSON and 2. keys may contain
  // characters comprising invalid identifiers.
  _out << _token[OpenQuotedKey] << key << _token[CloseQuotedKey];

  if(props->is_leaf()) {
    if(v != 0) {
      boost::apply_visitor(*this, *v);
    }
  } else {
    _out << "{";
    if(v != 0) {
      _out << _token[ValueKey];
      boost::apply_visitor(*this, *v);
      _out << ",";
    }
  }
}

PropertiesToString::PropertiesToString(std::ostream & out,
                                       const ToFormat to_format) :
  _token(OutputToken[to_format]), _out(out)
{ }

__END_NS_SSRC_WSPR_UTILITY