itkPSMDOMNodeXMLReader.cxx

/*=========================================================================
 *
 *  Copyright Insight Software Consortium
 *
 *  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
 *
 *         http://www.apache.org/licenses/LICENSE-2.0.txt
 *
 *  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 "itkPSMDOMNodeXMLReader.h"
#include "expat.h"

#include <fstream>

namespace itk
{

static void itkXMLParserStartElement( void* parser, const char* name, const char** atts )
{
  // Begin element handler that is registered with the XML_Parser.
  // This just casts the user data to a itkXMLParser and calls
  // StartElement.
  static_cast<PSMDOMNodeXMLReader*>(parser)->StartElement( name, atts );
}

static void itkXMLParserEndElement( void* parser, const char* name )
{
  // End element handler that is registered with the XML_Parser.  This
  // just casts the user data to a itkXMLParser and calls EndElement.
  static_cast<PSMDOMNodeXMLReader*>(parser)->EndElement( name );
}

static void itkXMLParserCharacterDataHandler( void* parser, const char* data, int length )
{
  // Character data handler that is registered with the XML_Parser.
  // This just casts the user data to a itkXMLParser and calls
  // CharacterDataHandler.
  static_cast<PSMDOMNodeXMLReader*>(parser)->CharacterDataHandler( data, length );
}

PSMDOMNodeXMLReader::PSMDOMNodeXMLReader() : m_Context(NULL)
{
}

void
PSMDOMNodeXMLReader::Update( std::istream& is )
{
  DOMNodeType* output = this->GetDOMNode();
  if ( output == NULL )
    {
    DOMNodePointer object = DOMNodeType::New();
    output = (DOMNodeType*)object;
    this->SetDOMNode( output );
    }

  output->RemoveAllAttributesAndChildren();
  this->m_Context = NULL;

  is >> std::noskipws;
  std::string s;
  while ( true )
    {
    char c = 0;
    is >> c;
    if ( !is.good() )
      {
      break;
      }
    s.append( 1, c );
    }

  XML_Parser parser = XML_ParserCreate( 0 );
  XML_SetElementHandler( parser, &itkXMLParserStartElement, &itkXMLParserEndElement );
  XML_SetCharacterDataHandler( parser, &itkXMLParserCharacterDataHandler );
  XML_SetUserData( parser, this );

  bool ok = XML_Parse( parser, s.data(), s.size(), false );
  if ( !ok )
    {
    ExceptionObject e( __FILE__, __LINE__ );
    std::string message( XML_ErrorString(XML_GetErrorCode(parser)) );
    e.SetDescription( message.c_str() );
    throw e;
    }

  XML_ParserFree( parser );
}

void
PSMDOMNodeXMLReader::Update()
{
  std::ifstream is( this->m_FileName.c_str() );
  if ( !is.is_open() )
    {
    itkExceptionMacro( "failed openning the input XML file" );
    }

  this->Update( is );

  is.close();
}

void
PSMDOMNodeXMLReader::StartElement( const char* name, const char** atts )
{
  DOMNodeType* node = NULL;
  if ( this->m_Context )
    {
    DOMNodePointer node1 = DOMNodeType::New();
    node = (DOMNodeType*)node1;
    this->m_Context->AddChildAtEnd( node );
    }
  else
    {
    node = this->GetDOMNode();
    }
  node->SetName( name );

  size_t i = 0;
  while ( atts[i] )
    {
    std::string key( atts[i++] );
    std::string value( atts[i++] );
    if ( StringTools::MatchWith(key,"id") )
      {
      node->SetID( value );
      }
    else
      {
      node->SetAttribute( key, value );
      }
    }

  this->m_Context = node;
}

void
PSMDOMNodeXMLReader::EndElement( const char* name )
{
  if ( this->m_Context->GetName() != name )
    {
    itkExceptionMacro( "start/end tag names mismatch" );
    }
  this->m_Context = dynamic_cast<PSMDOMNode *>(this->m_Context->GetParent());
}

void
PSMDOMNodeXMLReader::CharacterDataHandler( const char* text, int len )
{
  std::string s( text, len );

  StringTools::Trim( s );
  if ( s.size() == 0 )
    {
    return;
    }

  this->m_Context->AddText(s);
}

} // namespace itk