/*
 *
 *  Copyright (C) 1994-2010, OFFIS e.V.
 *  All rights reserved.  See COPYRIGHT file for details.
 *
 *  This software and supporting documentation were developed by
 *
 *    OFFIS e.V.
 *    R&D Division Health
 *    Escherweg 2
 *    D-26121 Oldenburg, Germany
 *
 *
 *  Module:  dcmdata
 *
 *  Author:  Gerd Ehlers, Andreas Barth, Andrew Hewett
 *
 *  Purpose: class DcmVR: Value Representation
 *
 *  Last Update:      $Author: joergr $
 *  Update Date:      $Date: 2010-10-14 13:14:10 $
 *  CVS/RCS Revision: $Revision: 1.39 $
 *  Status:           $State: Exp $
 *
 *  CVS/RCS Log at end of file
 *
 */


#include "dcmtk/config/osconfig.h"    /* make sure OS specific configuration is included first */
#include "dcmtk/dcmdata/dcvr.h"
#include "dcmtk/dcmdata/dctypes.h"

#define INCLUDE_CSTDLIB
#define INCLUDE_CSTRING
#include "dcmtk/ofstd/ofstdinc.h"

/*
 * global flags
 */
OFGlobal<OFBool> dcmEnableUnknownVRGeneration(OFTrue);
OFGlobal<OFBool> dcmEnableUnlimitedTextVRGeneration(OFTrue);
OFGlobal<OFBool> dcmEnableUnknownVRConversion(OFFalse);

/*
** VR property table
*/

#define DCMVR_PROP_NONE         0x00
#define DCMVR_PROP_NONSTANDARD  0x01
#define DCMVR_PROP_INTERNAL     0x02
#define DCMVR_PROP_EXTENDEDLENGTHENCODING 0x04
#define DCMVR_PROP_ISASTRING 0x08

struct DcmVREntry {
    DcmEVR vr;                  // Enumeration Value of Value representation
    const char* vrName;         // Name of Value representation
    size_t fValWidth;           // Length of minimal unit, used for swapping
    int propertyFlags;          // Normal, internal, non-standard vr
    Uint32 minValueLength;      // Minimum length of a single value (bytes)
    Uint32 maxValueLength;      // Maximum length of a single value (bytes)
};



static const DcmVREntry DcmVRDict[] = {

    { EVR_AE, "AE", sizeof(char), DCMVR_PROP_ISASTRING, 0, 16 },
    { EVR_AS, "AS", sizeof(char), DCMVR_PROP_ISASTRING, 4, 4 },
    { EVR_AT, "AT", sizeof(Uint16), DCMVR_PROP_NONE, 4, 4 },
    { EVR_CS, "CS", sizeof(char), DCMVR_PROP_ISASTRING, 0, 16 },
    { EVR_DA, "DA", sizeof(char), DCMVR_PROP_ISASTRING, 8, 10 },
    { EVR_DS, "DS", sizeof(char), DCMVR_PROP_ISASTRING, 0, 16 },
    { EVR_DT, "DT", sizeof(char), DCMVR_PROP_ISASTRING, 0, 26},
    { EVR_FL, "FL", sizeof(Float32), DCMVR_PROP_NONE, 4, 4 },
    { EVR_FD, "FD", sizeof(Float64), DCMVR_PROP_NONE, 8, 8 },
    { EVR_IS, "IS", sizeof(char), DCMVR_PROP_ISASTRING, 0, 12 },
    { EVR_LO, "LO", sizeof(char), DCMVR_PROP_ISASTRING, 0, 64 },
    { EVR_LT, "LT", sizeof(char), DCMVR_PROP_ISASTRING, 0, 10240 },
    { EVR_OB, "OB", sizeof(Uint8), DCMVR_PROP_EXTENDEDLENGTHENCODING, 0, DCM_UndefinedLength },
    { EVR_OF, "OF", sizeof(Float32), DCMVR_PROP_EXTENDEDLENGTHENCODING, 0, DCM_UndefinedLength },
    { EVR_OW, "OW", sizeof(Uint16), DCMVR_PROP_EXTENDEDLENGTHENCODING, 0, DCM_UndefinedLength },
    { EVR_PN, "PN", sizeof(char), DCMVR_PROP_ISASTRING, 0, 64 },
    { EVR_SH, "SH", sizeof(char), DCMVR_PROP_ISASTRING, 0, 16 },
    { EVR_SL, "SL", sizeof(Sint32), DCMVR_PROP_NONE, 4, 4 },
    { EVR_SQ, "SQ", 0, DCMVR_PROP_EXTENDEDLENGTHENCODING, 0, DCM_UndefinedLength },
    { EVR_SS, "SS", sizeof(Sint16), DCMVR_PROP_NONE, 2, 2 },
    { EVR_ST, "ST", sizeof(char), DCMVR_PROP_ISASTRING, 0, 1024 },
    { EVR_TM, "TM", sizeof(char), DCMVR_PROP_ISASTRING, 0, 16 },
    { EVR_UI, "UI", sizeof(char), DCMVR_PROP_ISASTRING, 0, 64 },
    { EVR_UL, "UL", sizeof(Uint32), DCMVR_PROP_NONE, 4, 4 },
    { EVR_US, "US", sizeof(Uint16), DCMVR_PROP_NONE, 2, 2 },
    { EVR_UT, "UT", sizeof(char), DCMVR_PROP_ISASTRING|DCMVR_PROP_EXTENDEDLENGTHENCODING, 0, DCM_UndefinedLength },
    { EVR_ox, "ox", sizeof(Uint8), DCMVR_PROP_NONSTANDARD | DCMVR_PROP_EXTENDEDLENGTHENCODING, 0, DCM_UndefinedLength },
    { EVR_xs, "xs", sizeof(Uint16), DCMVR_PROP_NONSTANDARD, 2, 2 },
    { EVR_lt, "lt", sizeof(Uint16), DCMVR_PROP_NONSTANDARD | DCMVR_PROP_EXTENDEDLENGTHENCODING, 0, DCM_UndefinedLength },
    { EVR_na, "na", 0, DCMVR_PROP_NONSTANDARD, 0, 0 },
    { EVR_up, "up", sizeof(Uint32), DCMVR_PROP_NONSTANDARD, 4, 4 },

    /* unique prefixes have been "invented" for the following internal VRs */
    { EVR_item, "it_EVR_item", 0,
      DCMVR_PROP_NONSTANDARD | DCMVR_PROP_INTERNAL, 0, 0 },
    { EVR_metainfo, "mi_EVR_metainfo", 0,
      DCMVR_PROP_NONSTANDARD | DCMVR_PROP_INTERNAL, 0, 0 },
    { EVR_dataset, "ds_EVR_dataset", 0,
      DCMVR_PROP_NONSTANDARD | DCMVR_PROP_INTERNAL, 0, 0 },
    { EVR_fileFormat, "ff_EVR_fileFormat", 0,
      DCMVR_PROP_NONSTANDARD | DCMVR_PROP_INTERNAL, 0, 0 },
    { EVR_dicomDir, "dd_EVR_dicomDir", 0,
      DCMVR_PROP_NONSTANDARD | DCMVR_PROP_INTERNAL, 0, 0 },
    { EVR_dirRecord, "dr_EVR_dirRecord", 0,
      DCMVR_PROP_NONSTANDARD | DCMVR_PROP_INTERNAL, 0, 0 },

    { EVR_pixelSQ, "ps_EVR_pixelSQ", sizeof(Uint8),
      DCMVR_PROP_NONSTANDARD | DCMVR_PROP_INTERNAL, 0, DCM_UndefinedLength },
    /* Moved from internal use to non standard only: necessary to distinguish from "normal" OB */
    { EVR_pixelItem, "pi", sizeof(Uint8),
      DCMVR_PROP_NONSTANDARD, 0, DCM_UndefinedLength },

    { EVR_UNKNOWN, "??", sizeof(Uint8), /* EVR_UNKNOWN (i.e. "future" VRs) should be mapped to UN or OB */
      DCMVR_PROP_NONSTANDARD | DCMVR_PROP_INTERNAL | DCMVR_PROP_EXTENDEDLENGTHENCODING, 0, DCM_UndefinedLength },

    /* Unknown Value Representation - Supplement 14 */
    { EVR_UN, "UN", sizeof(Uint8), DCMVR_PROP_EXTENDEDLENGTHENCODING, 0, DCM_UndefinedLength },

    /* Pixel Data - only used in ident() */
    { EVR_PixelData, "PixelData", 0, DCMVR_PROP_INTERNAL, 0, DCM_UndefinedLength },
    /* Overlay Data - only used in ident() */
    { EVR_OverlayData, "OverlayData", 0, DCMVR_PROP_INTERNAL, 0, DCM_UndefinedLength },

    { EVR_UNKNOWN2B, "??", sizeof(Uint8), /* illegal VRs, we assume no extended length coding */
      DCMVR_PROP_NONSTANDARD | DCMVR_PROP_INTERNAL , 0, DCM_UndefinedLength },

};

static const int DcmVRDict_DIM = sizeof(DcmVRDict) / sizeof(DcmVREntry);


/*
** Check the consistency of the DcmVRDict
*/

#ifdef DEBUG

#include "dcmtk/ofstd/ofstream.h"

class DcmVRDict_checker {
private:
    int error_found;
public:
    DcmVRDict_checker();
};

DcmVRDict_checker::DcmVRDict_checker()
  : error_found(OFFalse)
{
    for (int i=0; i<DcmVRDict_DIM; i++) {
        if (DcmVRDict[i].vr != i) {
            error_found = OFTrue;
            // we can't use ofConsole here because this piece of code
            // might be called before ofConsole is initialized.
            DCMDATA_FATAL("DcmVRDict: Internal ERROR: inconsistent indexing: " << DcmVRDict[i].vrName);
            abort();
        }
    }
}

const DcmVRDict_checker DcmVRDict_startup_check();

#endif

/*
** DcmVR member functions
*/

void
DcmVR::setVR(DcmEVR evr)
{
    if ( (OFstatic_cast(int, evr) >= 0) && (OFstatic_cast(int, evr) < DcmVRDict_DIM)) {
        vr = evr;
    } else {
        vr = EVR_UNKNOWN;
    }
}

void
DcmVR::setVR(const char* vrName)
{
    vr = EVR_UNKNOWN;   /* default */
    if ( vrName != NULL)
    {
        int found = OFFalse;
        int i = 0;
        for (i=0;  (!found && (i < DcmVRDict_DIM)); i++)
        {
            if (strncmp(vrName, DcmVRDict[i].vrName, 2) == 0)
            {
                found = OFTrue;
                vr = DcmVRDict[i].vr;
            }
        }
        /* Workaround: There have been reports of systems transmitting
         * illegal VR strings in explicit VR (i.e. "??") without using
         * extended length fields. This is particularly bad because the
         * DICOM committee has announced that all future VRs will use
         * extended length. In order to distinguish between these two
         * variants, we treat all unknown VRs consisting of uppercase
         * letters as "real" future VRs (and thus assume extended length).
         * All other VR strings are treated as "illegal" VRs.
         */
        register char c1 = *vrName;
        register char c2 = (c1)?(*(vrName+1)):('\0');
        if ((c1=='?')&&(c2=='?')) vr = EVR_UNKNOWN2B;
        if (!found && ((c1<'A')||(c1>'Z')||(c2<'A')||(c2>'Z'))) vr = EVR_UNKNOWN2B;
    }
}

DcmEVR
DcmVR::getValidEVR() const
{
    DcmEVR evr = EVR_UNKNOWN;

    if (isStandard()) {
        evr = vr;
    } else {
        switch (vr) {
        case EVR_up:
            evr = EVR_UL;
            break;
        case EVR_xs:
            evr = EVR_US;
            break;
        case EVR_lt:
            evr = EVR_OW;
            break;
        case EVR_ox:
        case EVR_pixelSQ:
            evr = EVR_OB;
            break;
        default:
            evr = EVR_UN;   /* handle as Unknown VR (Supplement 14) */
            break;
        }
    }

    /*
    ** If the generation of UN is not globally enabled then use OB instead.
    ** We may not want to generate UN if other software cannot handle it.
    */
    if (evr == EVR_UN)
    {
      if (!dcmEnableUnknownVRGeneration.get()) evr = EVR_OB; /* handle UN as if OB */
    }

    /*
    ** If the generation of UT is not globally enabled then use OB instead.
    ** We may not want to generate UT if other software cannot handle it.
    */
    if (evr == EVR_UT)
    {
      if (!dcmEnableUnlimitedTextVRGeneration.get()) evr = EVR_OB; /* handle UT as if OB */
    }
    return evr;
}

size_t
DcmVR::getValueWidth(void) const
{
    return DcmVRDict[vr].fValWidth;
}


const char*
DcmVR::getVRName() const
{
    return DcmVRDict[vr].vrName;
}

const char*
DcmVR::getValidVRName() const
{
    DcmVR avr(getValidEVR());
    return avr.getVRName();
}

OFBool
DcmVR::isStandard() const
{
    return (DcmVRDict[vr].propertyFlags & DCMVR_PROP_NONSTANDARD) ? OFFalse : OFTrue;
}

OFBool
DcmVR::isForInternalUseOnly() const
{
    return (DcmVRDict[vr].propertyFlags & DCMVR_PROP_INTERNAL) ? OFTrue : OFFalse;
}

/* returns true if VR represents a string */
OFBool
DcmVR::isaString() const
{
    return (DcmVRDict[vr].propertyFlags & DCMVR_PROP_ISASTRING) ? OFTrue : OFFalse;
}

/*
 * returns true if VR uses an extended length encoding
 * for explicit transfer syntaxes
 */
OFBool
DcmVR::usesExtendedLengthEncoding() const
{
    return (DcmVRDict[vr].propertyFlags & DCMVR_PROP_EXTENDEDLENGTHENCODING) ? OFTrue : OFFalse;
}

Uint32 DcmVR::getMinValueLength() const
{
    return (DcmVRDict[vr].minValueLength);
}

Uint32 DcmVR::getMaxValueLength() const
{
    return (DcmVRDict[vr].maxValueLength);
}

/* returns true if the vr is equivalent */
OFBool DcmVR::isEquivalent(const DcmVR& avr) const
{
    DcmEVR evr = avr.getEVR();
    if (vr == evr) return OFTrue;

    OFBool result = OFFalse;
    switch (vr)
    {
      case EVR_ox:
          result = (evr == EVR_OB || evr == EVR_OW);
          break;
      case EVR_lt:
          result = (evr == EVR_OW || evr == EVR_US || evr == EVR_SS);
          break;
      case EVR_OB:
          result = (evr == EVR_ox);
          break;
      case EVR_OW:
          result = (evr == EVR_ox || evr == EVR_lt);
          break;
      case EVR_up:
          result = (evr == EVR_UL);
          break;
      case EVR_UL:
          result = (evr == EVR_up);
          break;
      case EVR_xs:
          result = (evr == EVR_SS || evr == EVR_US);
          break;
      case EVR_SS:
      case EVR_US:
          result = (evr == EVR_xs || evr == EVR_lt);
          break;
      default:
          break;
    }
    return result;
}


/*
 * CVS/RCS Log:
 * $Log: dcvr.cc,v $
 * Revision 1.39  2010-10-14 13:14:10  joergr
 * Updated copyright header. Added reference to COPYRIGHT file.
 *
 * Revision 1.38  2010-03-01 09:08:45  uli
 * Removed some unnecessary include directives in the headers.
 *
 * Revision 1.37  2010-02-22 11:39:54  uli
 * Remove some unneeded includes.
 *
 * Revision 1.36  2009-12-04 17:08:11  joergr
 * Sightly modified some log messages.
 *
 * Revision 1.35  2009-11-04 09:58:10  uli
 * Switched to logging mechanism provided by the "new" oflog module
 *
 * Revision 1.34  2006-08-15 15:49:54  meichel
 * Updated all code in module dcmdata to correctly compile when
 *   all standard C++ classes remain in namespace std.
 *
 * Revision 1.33  2005/12/08 15:41:44  meichel
 * Changed include path schema for all DCMTK header files
 *
 * Revision 1.32  2005/11/15 18:28:04  meichel
 * Added new global flag dcmEnableUnknownVRConversion that enables the automatic
 *   re-conversion of defined length UN elements read in an explicit VR transfer
 *   syntax, if the real VR is defined in the data dictionary. Default is OFFalse,
 *   i.e. to retain the previous behavior.
 *
 * Revision 1.31  2005/11/15 16:59:25  meichel
 * Added new pseudo VR type EVR_lt that is used for LUT Data when read in
 *   implicit VR, which may be US, SS or OW. DCMTK always treats EVR_lt like OW.
 *
 * Revision 1.30  2004/02/04 16:47:59  joergr
 * Adapted type casts to new-style typecast operators defined in ofcast.h.
 * Removed acknowledgements with e-mail addresses from CVS log.
 *
 * Revision 1.29  2003/06/04 12:41:07  meichel
 * Cleaned up usage of boolean constants
 *
 * Revision 1.28  2003/03/21 13:08:04  meichel
 * Minor code purifications for warnings reported by MSVC in Level 4
 *
 * Revision 1.27  2002/12/06 13:00:31  joergr
 * Added support for new value representation Other Float String (OF).
 *
 * Revision 1.26  2002/11/27 12:06:54  meichel
 * Adapted module dcmdata to use of new header file ofstdinc.h
 *
 * Revision 1.25  2002/04/16 13:43:23  joergr
 * Added configurable support for C++ ANSI standard includes (e.g. streams).
 *
 * Revision 1.24  2001/11/02 13:18:52  meichel
 * Removed character sequences that could be interpreted as ISO C++ trigraphs
 *
 * Revision 1.23  2001/09/28 14:21:40  joergr
 * Replaced "cerr" by "CERR".
 *
 * Revision 1.22  2001/06/01 15:49:13  meichel
 * Updated copyright header
 *
 * Revision 1.21  2000/04/14 15:42:58  meichel
 * Global VR generation flags are now derived from OFGlobal and, thus,
 *   safe for use in multi-thread applications.
 *
 * Revision 1.20  2000/03/08 16:26:44  meichel
 * Updated copyright header.
 *
 * Revision 1.19  2000/03/03 14:05:38  meichel
 * Implemented library support for redirecting error messages into memory
 *   instead of printing them to stdout/stderr for GUI applications.
 *
 * Revision 1.18  2000/02/29 11:49:30  meichel
 * Removed support for VS value representation. This was proposed in CP 101
 *   but never became part of the standard.
 *
 * Revision 1.17  2000/02/03 16:35:12  joergr
 * Fixed bug: encapsulated data (pixel items) have never been loaded using
 * method 'loadAllDataIntoMemory'. Therefore, encapsulated pixel data was
 * never printed with 'dcmdump'.
 * Corrected bug that caused wrong calculation of group length for sequence
 * of items (e.g. encapsulated pixel data).
 *
 * Revision 1.16  1999/03/31 09:25:45  meichel
 * Updated copyright header in module dcmdata
 *
 *
 */