SimpleSAXParser.cc

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#include "Fireworks/Core/src/SimpleSAXParser.h"

std::string 
SimpleSAXParser::parseEntity(const std::string &entity)
{
   if (entity == "quot")
      return "\"";
   else if (entity == "amp")
      return "&";
   else if (entity == "lt")
      return "<";
   else if (entity == "gt")
      return ">";
   throw ParserError("Unknown entity " + entity);      
}

void
debug_state_machine(enum SimpleSAXParser::PARSER_STATES state)
{
#ifdef SIMPLE_SAX_PARSER_DEBUG
  static char *debug_states[] = {
      "IN_DOCUMENT",
      "IN_BEGIN_TAG",
      "IN_DONE",
      "IN_BEGIN_ELEMENT",
      "IN_ELEMENT_WHITESPACE",
      "IN_END_ELEMENT",
      "IN_ATTRIBUTE_KEY",
      "IN_END_TAG",
      "IN_DATA",
      "IN_BEGIN_ATTRIBUTE_VALUE",
      "IN_STRING",
      "IN_END_ATTRIBUTE_VALUE",
      "IN_STRING_ENTITY",
      "IN_DATA_ENTITY"
   };

   std::cerr << debug_states[state] << std::endl;
#endif
}

void 
SimpleSAXParser::parse(void)
{
   enum PARSER_STATES state = IN_DOCUMENT;
   // Current delimiters for strings in attributes.
   char stringDelims[] = "\"&";
   std::string attributeName;
   std::string attributeValue;
   std::string tmp;
   std::string currentData;
   
   while (state != IN_DONE)
   {
      debug_state_machine(state);

      switch(state)
      {
         // FIXME: IN_DOCUMENT should check the dtd...
         case IN_DOCUMENT:
            state = IN_DATA;
            if (skipChar('<'))
               state = IN_BEGIN_TAG;
            break;
         
         case IN_BEGIN_TAG:
            if (nextChar() >= 'A' && nextChar() <= 'z')
               state = IN_BEGIN_ELEMENT;
            else if (skipChar('/'))
               state = IN_END_ELEMENT;
            else
               throw ParserError("Bad tag");
            break;
            
         case IN_BEGIN_ELEMENT:
            m_attributes.clear();
            m_elementTags.push_back(getToken(" />"));
            if (nextChar() == ' ')
               state = IN_ELEMENT_WHITESPACE;
            else if (skipChar('/'))
               state = IN_END_ELEMENT;
            else if (skipChar('>'))
            {  
               startElement(m_elementTags.back(), m_attributes);
               state = IN_END_TAG;
            }
            else
               throw ParserError("Bad element.");
            break;
         
         case IN_ELEMENT_WHITESPACE:
            while(skipChar(' ') || skipChar('\n') || skipChar('\t'))
            {}
            
            if (nextChar() >= 'A' && nextChar() <= 'z')
               state=IN_ATTRIBUTE_KEY;
            else if (nextChar() == '/')
               state = IN_END_ELEMENT;
            else
               throw ParserError("Syntax error in element" + m_elementTags.back());
            break;
         
         case IN_ATTRIBUTE_KEY:
            attributeName = getToken('=');
            state = IN_BEGIN_ATTRIBUTE_VALUE;
            break;
            
         case IN_BEGIN_ATTRIBUTE_VALUE:
            if (skipChar('"'))
            {
               state = IN_STRING;
               attributeValue.clear();
               stringDelims[0] = '\"';
            }
            else if (skipChar('\''))
            {
               state = IN_STRING;
               attributeValue.clear();
               stringDelims[0] = '\'';               
            }
            else
               throw ParserError("Expecting quotes.");
            break;
            
         case IN_STRING:
            attributeValue += getToken(stringDelims);
            if (skipChar(stringDelims[0]))
            {
               // Save the attributes in order, replacing those that are
               // specified more than once.
               Attribute attr(attributeName, attributeValue);
               Attributes::iterator i = std::lower_bound(m_attributes.begin(),
                                                         m_attributes.end(),
                                                         attr);
               if (i != m_attributes.end() && i->key == attr.key)
                  throw ParserError("Attribute " + i->key + " defined more than once");
               m_attributes.insert(i, attr);
               state = IN_END_ATTRIBUTE_VALUE;
            }
            else if (skipChar(stringDelims[1]))
               state = IN_STRING_ENTITY;
            else
               throw ParserError("Unexpected end of input at " + attributeValue);
            break;
         
         case IN_END_ATTRIBUTE_VALUE:
            getToken(" />");
            if (nextChar() == ' ')
               state = IN_ELEMENT_WHITESPACE;
            else if (skipChar('/'))
               state = IN_END_ELEMENT;
            else if (skipChar('>'))
            {
               startElement(m_elementTags.back(), m_attributes);
               state = IN_END_TAG;
            }
            break;
         
         case IN_END_ELEMENT:
            tmp = getToken('>');
            if (!tmp.empty() && tmp != m_elementTags.back())
               throw ParserError("Non-matching closing element " 
                                 + tmp + " for " + attributeValue);
            endElement(tmp);
            m_elementTags.pop_back();
            state = IN_END_TAG;
            break;
         
         case IN_END_TAG:
            if (nextChar() == EOF)
               return;
            else if (skipChar('<'))
               state = IN_BEGIN_TAG;
            else
               state = IN_DATA;
            break;
       
         case IN_DATA:
            currentData += getToken("<&");
            if (skipChar('&'))
               state = IN_DATA_ENTITY;
            else if (skipChar('<'))
            {
               data(currentData);
               currentData.clear();               
               state = IN_BEGIN_TAG;
            }
            else if (nextChar() == EOF)
            {
               data(currentData);
               return;
            } 
            else
               throw ParserError("Unexpected end of input in element " + m_elementTags.back() + currentData);
            break;
         
         case IN_DATA_ENTITY:
            currentData += parseEntity(getToken(';'));
            state = IN_DATA;
            break;
            
         case IN_STRING_ENTITY:
            attributeValue += parseEntity(getToken(';'));
            state = IN_STRING;
            break;
         
         case IN_DONE:
            return;
      }
   }
}

SimpleSAXParser::~SimpleSAXParser() { delete [] m_buffer;}

bool
fgettoken(std::istream &in, char **buffer, size_t *maxSize, const char *separators,
          int *firstChar)
{
  // if the passed first character is EOF or a separator,
  // return an empty otherwise use it as first character
  // of the buffer. 
  if (*firstChar == EOF || (int) separators[0] == *firstChar || strchr(separators + 1, *firstChar))
  {
    (*buffer)[0] = 0;
    return true;
  }
  else
    (*buffer)[0] = (char) *firstChar;

  size_t i = 1;

  while (true)
  {
    if (i >= *maxSize)
    {
      *maxSize += 1024;
      *buffer = (char*) realloc(*buffer, *maxSize);
      if (!*buffer)
         return false;
    }

    int c = in.get();

    if (c == EOF)
    {
       (*buffer)[i] = 0;
       *firstChar = c;
       return false;
    }
    
    if (separators[0] == c || strchr(separators + 1, c))
    {
      (*buffer)[i] = 0;
      *firstChar = c;
      return true;
    }

    (*buffer)[i++] = (char) c;
  }
}