gdcmVL.h

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/*=========================================================================
 
  Program: GDCM (Grassroots DICOM). A DICOM library
 
  Copyright (c) 2006-2011 Mathieu Malaterre
  All rights reserved.
  See Copyright.txt or http://gdcm.sourceforge.net/Copyright.html for details.
 
     This software is distributed WITHOUT ANY WARRANTY; without even
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
     PURPOSE.  See the above copyright notice for more information.
 
=========================================================================*/
#ifndef GDCMVL_H
#define GDCMVL_H
 
#include "gdcmTypes.h"
 
#include <iostream>
 
namespace gdcm
{
 
class GDCM_EXPORT VL
{
public:
  typedef uint32_t Type;
  VL(uint32_t vl = 0) : ValueLength(vl) { }
 
  // FIXME: ugly
  static uint32_t GetVL32Max() { return 0xFFFFFFFF; }
  static uint16_t GetVL16Max() { return 0xFFFF; }
 
  bool IsUndefined() const {
    return ValueLength == 0xFFFFFFFF;
  }
  void SetToUndefined() {
    ValueLength = 0xFFFFFFFF;
  }
 
  bool IsOdd() const {
    return !IsUndefined() && ValueLength % 2;
  }
 
  VL& operator+=(VL const &vl) {
    ValueLength += vl.ValueLength;
    return *this;
  }
  VL& operator++() {
    ++ValueLength;
    return *this;
  }
  VL operator++(int) {
    uint32_t tmp(ValueLength);
    ++ValueLength;
    return tmp;
  }
 
  operator uint32_t () const { return ValueLength; }
 
  VL GetLength() const {
    // VL cannot know it's length...well in implicit yes...
    // TODO: need to check we cannot call this function from an Explicit element
    return 4;
  }
 
  friend std::ostream& operator<<(std::ostream& os, const VL& vl);
 
  // PURPOSELY not implemented (could not differentiate 16bits vs 32bits VL)
  //friend std::istream& operator>>(std::istream& is, VL& n);
 
  template <typename TSwap>
  std::istream &Read(std::istream &is)
    {
    is.read((char*)(&ValueLength), sizeof(uint32_t));
    TSwap::SwapArray(&ValueLength,1);
    return is;
    }
 
  template <typename TSwap>
  std::istream &Read16(std::istream &is)
    {
    uint16_t copy;
    is.read((char*)(&copy), sizeof(uint16_t));
    TSwap::SwapArray(&copy,1);
    ValueLength = copy;
    assert( ValueLength <=  65535 /*UINT16_MAX*/ ); // ?? doh !
    return is;
    }
 
  template <typename TSwap>
  const std::ostream &Write(std::ostream &os) const
    {
    uint32_t copy = ValueLength;
    if( IsOdd() )
      {
      ++copy;
      }
    TSwap::SwapArray(&copy,1);
    return os.write((char*)(&copy), sizeof(uint32_t));
    }
 
  template <typename TSwap>
  const std::ostream &Write16(std::ostream &os) const
    {
    assert( ValueLength <=   65535 /*UINT16_MAX*/ );
    uint16_t copy = (uint16_t)ValueLength;
    if( IsOdd() )
      {
      ++copy;
      }
    TSwap::SwapArray(&copy,1);
    return os.write((char*)(&copy), sizeof(uint16_t));
    }
 
private:
  uint32_t ValueLength;
};
//----------------------------------------------------------------------------
inline std::ostream& operator<<(std::ostream& os, const VL& val)
{
  os << /*std::hex <<*/ val.ValueLength;
  return os;
}
 
} // end namespace gdcm
 
#endif //GDCMVL_H