part of xml parser

typedef struct XML_ParserStruct *XML_Parser;

struct XML_ParserStruct {
  /* The first member must be userData so that the XML_GetUserData
     macro works. */
  void *m_userData;
  void *m_handlerArg;
  char *m_buffer;
  const XML_Memory_Handling_Suite m_mem;
  /* first character to be parsed */
  const char *m_bufferPtr;
  /* past last character to be parsed */
  char *m_bufferEnd;
  /* allocated end of buffer */
  const char *m_bufferLim;
  XML_Index m_parseEndByteIndex;
  const char *m_parseEndPtr;
  XML_Char *m_dataBuf;
  XML_Char *m_dataBufEnd;
  XML_StartElementHandler m_startElementHandler;
  XML_EndElementHandler m_endElementHandler;
  XML_CharacterDataHandler m_characterDataHandler;
  XML_ProcessingInstructionHandler m_processingInstructionHandler;
  XML_CommentHandler m_commentHandler;
  XML_StartCdataSectionHandler m_startCdataSectionHandler;
  XML_EndCdataSectionHandler m_endCdataSectionHandler;
  XML_DefaultHandler m_defaultHandler;
  XML_StartDoctypeDeclHandler m_startDoctypeDeclHandler;
  XML_EndDoctypeDeclHandler m_endDoctypeDeclHandler;
  XML_UnparsedEntityDeclHandler m_unparsedEntityDeclHandler;
  XML_NotationDeclHandler m_notationDeclHandler;
  XML_StartNamespaceDeclHandler m_startNamespaceDeclHandler;
  XML_EndNamespaceDeclHandler m_endNamespaceDeclHandler;
  XML_NotStandaloneHandler m_notStandaloneHandler;
  XML_ExternalEntityRefHandler m_externalEntityRefHandler;
  XML_Parser m_externalEntityRefHandlerArg;
  XML_SkippedEntityHandler m_skippedEntityHandler;
  XML_UnknownEncodingHandler m_unknownEncodingHandler;
  XML_ElementDeclHandler m_elementDeclHandler;
  XML_AttlistDeclHandler m_attlistDeclHandler;
  XML_EntityDeclHandler m_entityDeclHandler;
  XML_XmlDeclHandler m_xmlDeclHandler;
  const ENCODING *m_encoding;
  INIT_ENCODING m_initEncoding;
  const ENCODING *m_internalEncoding;
  const XML_Char *m_protocolEncodingName;
  XML_Bool m_ns;
  XML_Bool m_ns_triplets;
  void *m_unknownEncodingMem;
  void *m_unknownEncodingData;
  void *m_unknownEncodingHandlerData;
  void (XMLCALL *m_unknownEncodingRelease)(void *);
  PROLOG_STATE m_prologState;
  Processor *m_processor;
  enum XML_Error m_errorCode;
  const char *m_eventPtr;
  const char *m_eventEndPtr;
  const char *m_positionPtr;
  OPEN_INTERNAL_ENTITY *m_openInternalEntities;
  OPEN_INTERNAL_ENTITY *m_freeInternalEntities;
  XML_Bool m_defaultExpandInternalEntities;
  int m_tagLevel;
  ENTITY *m_declEntity;
  const XML_Char *m_doctypeName;
  const XML_Char *m_doctypeSysid;
  const XML_Char *m_doctypePubid;
  const XML_Char *m_declAttributeType;
  const XML_Char *m_declNotationName;
  const XML_Char *m_declNotationPublicId;
  ELEMENT_TYPE *m_declElementType;
  ATTRIBUTE_ID *m_declAttributeId;
  XML_Bool m_declAttributeIsCdata;
  XML_Bool m_declAttributeIsId;
  DTD *m_dtd;
  const XML_Char *m_curBase;
  TAG *m_tagStack;
  TAG *m_freeTagList;
  BINDING *m_inheritedBindings;
  BINDING *m_freeBindingList;
  int m_attsSize;
  int m_nSpecifiedAtts;
  int m_idAttIndex;
  ATTRIBUTE *m_atts;
  NS_ATT *m_nsAtts;
  unsigned long m_nsAttsVersion;
  unsigned char m_nsAttsPower;
  POSITION m_position;
  STRING_POOL m_tempPool;
  STRING_POOL m_temp2Pool;
  char *m_groupConnector;
  unsigned int m_groupSize;
  XML_Char m_namespaceSeparator;
  XML_Parser m_parentParser;
  XML_ParsingStatus m_parsingStatus;
#ifdef XML_DTD
  XML_Bool m_isParamEntity;
  XML_Bool m_useForeignDTD;
  enum XML_ParamEntityParsing m_paramEntityParsing;
#endif
};

#ifdef XML_UNICODE     /* Information is UTF-16 encoded. */
#ifdef XML_UNICODE_WCHAR_T
typedef wchar_t XML_Char;
typedef wchar_t XML_LChar;
#else
typedef unsigned short XML_Char;
typedef char XML_LChar;
#endif /* XML_UNICODE_WCHAR_T */
#else                  /* Information is UTF-8 encoded. */
typedef char XML_Char;
typedef char XML_LChar;
#endif /* XML_UNICODE */

static XML_Parser
parserCreate(const XML_Char *encodingName,
             const XML_Memory_Handling_Suite *memsuite,
             const XML_Char *nameSep,
             DTD *dtd)
{
  XML_Parser parser;

  if (memsuite) {
    XML_Memory_Handling_Suite *mtemp;
    parser = (XML_Parser)
      memsuite->malloc_fcn(sizeof(struct XML_ParserStruct));
    if (parser != NULL) {
      mtemp = (XML_Memory_Handling_Suite *)&(parser->m_mem);
      mtemp->malloc_fcn = memsuite->malloc_fcn;
      mtemp->realloc_fcn = memsuite->realloc_fcn;
      mtemp->free_fcn = memsuite->free_fcn;
    }
  }
  else {
    XML_Memory_Handling_Suite *mtemp;
    parser = (XML_Parser)malloc(sizeof(struct XML_ParserStruct));
    if (parser != NULL) {
      mtemp = (XML_Memory_Handling_Suite *)&(parser->m_mem);
      mtemp->malloc_fcn = malloc;
      mtemp->realloc_fcn = realloc;
      mtemp->free_fcn = free;
    }
  }

  if (!parser)
    return parser;

  buffer = NULL;
  bufferLim = NULL;

  attsSize = INIT_ATTS_SIZE;
  atts = (ATTRIBUTE *)MALLOC(attsSize * sizeof(ATTRIBUTE));
  if (atts == NULL) {
    FREE(parser);
    return NULL;
  }
  dataBuf = (XML_Char *)MALLOC(INIT_DATA_BUF_SIZE * sizeof(XML_Char));
  if (dataBuf == NULL) {
    FREE(atts);
    FREE(parser);
    return NULL;
  }
  dataBufEnd = dataBuf + INIT_DATA_BUF_SIZE;

  if (dtd)
    _dtd = dtd;
  else {
    _dtd = dtdCreate(&parser->m_mem);
    if (_dtd == NULL) {
      FREE(dataBuf);
      FREE(atts);
      FREE(parser);
      return NULL;
    }
  }

  freeBindingList = NULL;
  freeTagList = NULL;
  freeInternalEntities = NULL;

  groupSize = 0;
  groupConnector = NULL;

  unknownEncodingHandler = NULL;
  unknownEncodingHandlerData = NULL;

  namespaceSeparator = ASCII_EXCL;
  ns = XML_FALSE;
  ns_triplets = XML_FALSE;

  nsAtts = NULL;
  nsAttsVersion = 0;
  nsAttsPower = 0;

  poolInit(&tempPool, &(parser->m_mem));
  poolInit(&temp2Pool, &(parser->m_mem));
  parserInit(parser, encodingName);

  if (encodingName && !protocolEncodingName) {
    XML_ParserFree(parser);
    return NULL;
  }

  if (nameSep) {
    ns = XML_TRUE;
    internalEncoding = XmlGetInternalEncodingNS();
    namespaceSeparator = *nameSep;
  }
  else {
    internalEncoding = XmlGetInternalEncoding();
  }

  return parser;
}

//create parser,xml syntax analizer

XML_Parser xParser= parserCreate(0);

//create documentHandler instance

xDocumentHandler = new MyDocumentHandler();

//register documentHandler
xParser->setDocumentHandler( xDocumentHandler);

//register EventHandler

XML_SetElementHandler(xParser,call_callbackStartElement,call_callbackEndElement);

......
// parse ***.xml
try
  {
    if( xParser->GetDocumentHandler() )  

　　　　xParser->GetDocumentHandler()->startDocument();

　　xParser->parse( aParserInput );//sax event Notify

    if( xParser->GetDocumentHandler() )  

　　　　 xParser->GetDocumentHandler()->endDocument();
   }

ps: above fragments are fetched from the usage in openoffice