/afs/cern.ch/work/a/aaltunda/public/www/CMSSW_6_2_5/src/GeneratorInterface/LHEInterface/src/XMLUtils.cc

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#include <iostream>
#include <memory>
#include <string>
#include <cstring>

#include <xercesc/util/PlatformUtils.hpp>
#include <xercesc/util/XMLString.hpp>
#include <xercesc/util/XMLUni.hpp>
#include <xercesc/sax2/SAX2XMLReader.hpp>
#include <xercesc/sax2/XMLReaderFactory.hpp>

#include "FWCore/Utilities/interface/Exception.h"

#include "Utilities/StorageFactory/interface/IOTypes.h"
#include "Utilities/StorageFactory/interface/Storage.h"

#include "XMLUtils.h"

XERCES_CPP_NAMESPACE_USE
#define BUF_SIZE 8192 

namespace lhef {

StorageWrap::StorageWrap(Storage *storage) :
        storage(storage)
{
}

StorageWrap::~StorageWrap()
{
        storage->close();
}

unsigned int XMLDocument::XercesPlatform::instances = 0;

XMLDocument::XercesPlatform::XercesPlatform()
{
        if (!instances++) {
                try {
                        XMLPlatformUtils::Initialize();
                } catch(const XMLException &e) {
                        throw cms::Exception("XMLDocument")
                                << "XMLPlatformUtils::Initialize failed "
                                   "because of: "
                                << XMLSimpleStr(e.getMessage()) << std::endl;
                }
        }
}

XMLDocument::XercesPlatform::~XercesPlatform()
{
        if (!--instances)
                XMLPlatformUtils::Terminate();
}

XMLDocument::XMLDocument(std::auto_ptr<std::istream> &in, Handler &handler) :
        platform(new XercesPlatform()),
        source(new STLInputSource(in)),
        parser(XMLReaderFactory::createXMLReader()),
        done(false)
{
        init(handler);
}

XMLDocument::XMLDocument(std::auto_ptr<StorageWrap> &in, Handler &handler) :
        platform(new XercesPlatform()),
        source(new StorageInputSource(in)),
        parser(XMLReaderFactory::createXMLReader()),
        done(false)
{
        init(handler);
}

void XMLDocument::init(Handler &handler)
{
        try {
                parser->setFeature(XMLUni::fgSAX2CoreValidation, false);
                parser->setFeature(XMLUni::fgSAX2CoreNameSpaces, false);
                parser->setFeature(XMLUni::fgXercesSchema, false);
                parser->setFeature(XMLUni::fgXercesSchemaFullChecking, false);

                parser->setContentHandler(&handler);
                parser->setLexicalHandler(&handler);
                parser->setErrorHandler(&handler);

                if (!parser->parseFirst(*source, token))
                        throw cms::Exception("XMLParseError")
                                << "SAXParser::parseFirst failed" << std::endl;
        } catch(const XMLException &e) {
                throw cms::Exception("XMLDocument")
                        << "XMLPlatformUtils::Initialize failed because of "
                        << XMLSimpleStr(e.getMessage()) << std::endl;
        } catch(const SAXException &e) {
                throw cms::Exception("XMLDocument")
                        << "XML parser reported: "
                        << XMLSimpleStr(e.getMessage()) << "." << std::endl;  
        }
}

XMLDocument::~XMLDocument()
{
}

bool XMLDocument::parse()
{
        try {
                if (done || parser->getErrorCount())
                        return false;

                done = !parser->parseNext(token);
        } catch(const XMLException &e) {
                throw cms::Exception("XMLDocument")
                        << "XMLPlatformUtils::Initialize failed because of "
                        << XMLSimpleStr(e.getMessage()) << std::endl;
        } catch(const SAXException &e) {
                throw cms::Exception("XMLDocument")
                        << "XML parser reported: "
                        << XMLSimpleStr(e.getMessage()) << "." << std::endl;  
        }

        return !done;
}

CBInputStream::Reader::~Reader()
{
}

CBInputStream::CBInputStream(Reader &reader) :
        reader(reader)
{
}

CBInputStream::~CBInputStream()
{
}

unsigned int CBInputStream::readBytes(XMLByte* const buf,
                                      const unsigned int size)
{
        char *rawBuf = reinterpret_cast<char*>(buf);
        unsigned int bytes = size * sizeof(XMLByte);
        unsigned int read = 0;

        while(read < bytes) {
                if (buffer.empty()) {
                        buffer = reader.data();
                        if (buffer.empty())
                                break;
                }

                unsigned int len = buffer.length();
                unsigned int rem = bytes - read;
                if (rem < len) {
                        std::memcpy(rawBuf + read, buffer.c_str(), rem);
                        buffer.erase(0, rem);
                        read += rem;
                        break;
                }

                std::memcpy(rawBuf + read, buffer.c_str(), len);
                buffer.clear();
                read += len;
        }

        read /= sizeof(XMLByte);
        pos += read;

        return read;
}

STLInputStream::STLInputStream(std::istream &in) :
        in(in)
{
        if (in.bad())
                throw cms::Exception("FileStreamError")
                        << "I/O stream bad in STLInputStream::STLInputStream()"
                        << std::endl;
}

STLInputStream::~STLInputStream()
{
}

unsigned int STLInputStream::readBytes(XMLByte* const buf,
                                       const unsigned int size)
{
        char *rawBuf = reinterpret_cast<char*>(buf);
        unsigned int bytes = size * sizeof(XMLByte);
        in.read(rawBuf, bytes);
        unsigned int readBytes = in.gcount();

        if (in.bad())
                throw cms::Exception("FileStreamError")
                        << "I/O stream bad in STLInputStream::readBytes()"
                        << std::endl;

        unsigned int read = (unsigned int)(readBytes / sizeof(XMLByte));
        unsigned int rest = (unsigned int)(readBytes % sizeof(XMLByte));
        for(unsigned int i = 1; i <= rest; i++)
                in.putback(rawBuf[readBytes - i]);

        pos += read;
        return read;
}

StorageInputStream::StorageInputStream(StorageWrap &in) :
        in(in),
        lstr(LZMA_STREAM_INIT),
        compression_(false),
        lasttotal_(0)
{
  // Check the kind of file.
  char header[6];
  /*unsigned int s = */ in->read(header, 6);
  in->position(0, Storage::SET);
  // Let's use lzma to start with.
  if (header[1] == '7'
      && header[2] == 'z'
      && header[3] == 'X'
      && header[4] == 'Z')
  {
    compression_ = true;
    lstr = LZMA_STREAM_INIT;
    // We store the beginning of the outBuffer to make sure
    // we can always update previous results.

#if LZMA_VERSION <= UINT32_C(49990030)
    int ret = lzma_auto_decoder(&lstr, NULL, NULL);
#else
    int ret = lzma_auto_decoder(&lstr, -1, 0);
#endif

    if (ret != LZMA_OK)
    {
      lzma_end(&lstr);
      throw cms::Exception("IO") << "Error while reading compressed LHE file";
    }
  }
}

StorageInputStream::~StorageInputStream()
{
  lzma_end(&(lstr));
}

unsigned int StorageInputStream::readBytes(XMLByte* const buf,
                                           const unsigned int size)
{
  // Simple read-in write-out in case
  if (!compression_)
  {
    void *rawBuf = reinterpret_cast<void*>(buf);
    unsigned int bytes = size * sizeof(XMLByte);
    unsigned int readBytes = in->read(rawBuf, bytes);

    unsigned int read = (unsigned int)(readBytes / sizeof(XMLByte));
    unsigned int rest = (unsigned int)(readBytes % sizeof(XMLByte));
    if (rest)
      in->position(-(IOOffset)rest, Storage::CURRENT);

    /*for (unsigned int i = 0; i < read; ++i){
      std::cout << buf[i] ;
    }*/
 
    pos += read;
    return read;
  }
  // Compressed case. 
  // We simply read as many bytes as we can and we 
  // uncompress them in the output buffer.
  // We never decompress more bytes we were asked by
  // xerces. 
  // In case we read from file more bytes than needed 
  // we simply rollback by the (hopefully) correct amount.
  // If we don't read enough bytes, we simply return
  // the amount of bytes read and we wait for being called
  // again by xerces.
  unsigned int bytes = size * sizeof(XMLByte);
//  std::cout << "bites " << bytes << std::endl;
  uint8_t inBuf[BUF_SIZE];
  unsigned int rd = in->read((void*)inBuf, BUF_SIZE);
  lstr.next_in = inBuf;
  lstr.avail_in = rd;
  lstr.next_out = buf;
  lstr.avail_out = bytes;
/*  for (unsigned int i = 0; i < size; ++i){
    std::cout << buf[i] ;
  }  
  std::cout << std::endl;*/

  int ret = lzma_code(&lstr, LZMA_RUN);
  if(ret != LZMA_OK && ret != LZMA_STREAM_END) {  /* decompression error */
    lzma_end(&lstr);
    throw cms::Exception("IO") << "Error while reading compressed LHE file";
  }
  // If we did not consume everything we put it back.
//  std::cout << "lstr.avail_in " << lstr.avail_in << " lstr.total_in " << lstr.total_in << std::endl;
//  std::cout << "lstr.avail_out " << lstr.avail_out << " lstr.total_out " << lstr.total_out << std::endl;
  if (lstr.avail_in){
    std::cout << "rolling back" << std::endl;
    in->position(-(IOOffset)(lstr.avail_in), Storage::CURRENT);    
  }  
  pos = lstr.total_out;
  unsigned int read = lstr.total_out - lasttotal_;
  lasttotal_ = lstr.total_out;
  return read;
}

} // namespace lhef