/******************************************************************************
 *
 * Project:  DXF Translator
 * Purpose:  Implements OGRDXFLayer class.
 * Author:   Frank Warmerdam, warmerdam@pobox.com
 *
 ******************************************************************************
 * Copyright (c) 2009, Frank Warmerdam <warmerdam@pobox.com>
 * Copyright (c) 2011-2013, Even Rouault <even dot rouault at mines-paris dot org>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 ****************************************************************************/

#include "ogr_dxf.h"
#include "cpl_conv.h"
#include "ogrdxf_polyline_smooth.h"
#include "ogr_api.h"

#include <cmath>

CPL_CVSID("$Id: ogrdxflayer.cpp 37837 2017-03-23 22:13:09Z rouault $");

/************************************************************************/
/*                            OGRDXFLayer()                             */
/************************************************************************/

OGRDXFLayer::OGRDXFLayer( OGRDXFDataSource *poDSIn ) :
    poDS(poDSIn),
    poFeatureDefn(new OGRFeatureDefn( "entities" )),
    iNextFID(0)
{
    poFeatureDefn->Reference();

    poDS->AddStandardFields( poFeatureDefn );

    if( !poDS->InlineBlocks() )
    {
        OGRFieldDefn  oScaleField( "BlockScale", OFTRealList );
        poFeatureDefn->AddFieldDefn( &oScaleField );

        OGRFieldDefn  oBlockAngleField( "BlockAngle", OFTReal );
        poFeatureDefn->AddFieldDefn( &oBlockAngleField );
    }

    SetDescription( poFeatureDefn->GetName() );
}

/************************************************************************/
/*                           ~OGRDXFLayer()                           */
/************************************************************************/

OGRDXFLayer::~OGRDXFLayer()

{
    ClearPendingFeatures();
    if( m_nFeaturesRead > 0 && poFeatureDefn != NULL )
    {
        CPLDebug( "DXF", "%d features read on layer '%s'.",
                  (int) m_nFeaturesRead,
                  poFeatureDefn->GetName() );
    }

    if( poFeatureDefn )
        poFeatureDefn->Release();
}

/************************************************************************/
/*                        ClearPendingFeatures()                        */
/************************************************************************/

void OGRDXFLayer::ClearPendingFeatures()

{
    while( !apoPendingFeatures.empty() )
    {
        delete apoPendingFeatures.front();
        apoPendingFeatures.pop();
    }
}

/************************************************************************/
/*                            ResetReading()                            */
/************************************************************************/

void OGRDXFLayer::ResetReading()

{
    iNextFID = 0;
    ClearPendingFeatures();
    poDS->RestartEntities();
}

/************************************************************************/
/*                      TranslateGenericProperty()                      */
/*                                                                      */
/*      Try and convert entity properties handled similarly for most    */
/*      or all entity types.                                            */
/************************************************************************/

void OGRDXFLayer::TranslateGenericProperty( OGRFeature *poFeature,
                                            int nCode, char *pszValue )

{
    switch( nCode )
    {
      case 8:
        poFeature->SetField( "Layer", TextUnescape(pszValue) );
        break;

      case 100:
      {
          CPLString osSubClass = poFeature->GetFieldAsString("SubClasses");
          if( !osSubClass.empty() )
              osSubClass += ":";
          osSubClass += pszValue;
          poFeature->SetField( "SubClasses", osSubClass.c_str() );
      }
      break;

      case 62:
        oStyleProperties["Color"] = pszValue;
        break;

      case 6:
        poFeature->SetField( "Linetype", TextUnescape(pszValue) );
        break;

      case 370:
      case 39:
        oStyleProperties["LineWeight"] = pszValue;
        break;

      case 5:
        poFeature->SetField( "EntityHandle", pszValue );
        break;

        // Extended entity data
      case 1000:
      case 1002:
      case 1004:
      case 1005:
      case 1040:
      case 1041:
      case 1070:
      case 1071:
      {
          CPLString osAggregate = poFeature->GetFieldAsString("ExtendedEntity");

          if( !osAggregate.empty() )
              osAggregate += " ";
          osAggregate += pszValue;

          poFeature->SetField( "ExtendedEntity", osAggregate );
      }
      break;

      // OCS vector.
      case 210:
        oStyleProperties["210_N.dX"] = pszValue;
        break;

      case 220:
        oStyleProperties["220_N.dY"] = pszValue;
        break;

      case 230:
        oStyleProperties["230_N.dZ"] = pszValue;
        break;

      default:
        break;
    }
}

/************************************************************************/
/*                          PrepareLineStyle()                          */
/************************************************************************/

void OGRDXFLayer::PrepareLineStyle( OGRFeature *poFeature )

{
    CPLString osLayer = poFeature->GetFieldAsString("Layer");

/* -------------------------------------------------------------------- */
/*      Is the layer disabled/hidden/frozen/off?                        */
/* -------------------------------------------------------------------- */
    int bHidden =
        EQUAL(poDS->LookupLayerProperty( osLayer, "Hidden" ), "1");

/* -------------------------------------------------------------------- */
/*      Work out the color for this feature.                            */
/* -------------------------------------------------------------------- */
    int nColor = 256;

    if( oStyleProperties.count("Color") > 0 )
        nColor = atoi(oStyleProperties["Color"]);

    // Use layer color?
    if( nColor < 1 || nColor > 255 )
    {
        const char *pszValue = poDS->LookupLayerProperty( osLayer, "Color" );
        if( pszValue != NULL )
            nColor = atoi(pszValue);
    }

    if( nColor < 1 || nColor > 255 )
        return;

/* -------------------------------------------------------------------- */
/*      Get line weight if available.                                   */
/* -------------------------------------------------------------------- */
    double dfWeight = 0.0;

    if( oStyleProperties.count("LineWeight") > 0 )
    {
        CPLString osWeight = oStyleProperties["LineWeight"];

        if( osWeight == "-1" )
            osWeight = poDS->LookupLayerProperty(osLayer,"LineWeight");

        dfWeight = CPLAtof(osWeight) / 100.0;
    }

/* -------------------------------------------------------------------- */
/*      Do we have a dash/dot line style?                               */
/* -------------------------------------------------------------------- */
    const char *pszPattern = poDS->LookupLineType(
        poFeature->GetFieldAsString("Linetype") );

/* -------------------------------------------------------------------- */
/*      Format the style string.                                        */
/* -------------------------------------------------------------------- */
    CPLString osStyle;
    const unsigned char *pabyDXFColors = ACGetColorTable();

    osStyle.Printf( "PEN(c:#%02x%02x%02x",
                    pabyDXFColors[nColor*3+0],
                    pabyDXFColors[nColor*3+1],
                    pabyDXFColors[nColor*3+2] );

    if( bHidden )
        osStyle += "00";

    if( dfWeight > 0.0 )
    {
        char szBuffer[64];
        CPLsnprintf(szBuffer, sizeof(szBuffer), "%.2g", dfWeight);
        osStyle += CPLString().Printf( ",w:%sg", szBuffer );
    }

    if( pszPattern )
    {
        osStyle += ",p:\"";
        osStyle += pszPattern;
        osStyle += "\"";
    }

    osStyle += ")";

    poFeature->SetStyleString( osStyle );
}

/************************************************************************/
/*                            OCSTransformer                            */
/************************************************************************/

class OCSTransformer : public OGRCoordinateTransformation
{
private:
    double adfN[3];
    double adfAX[3];
    double adfAY[3];

    double dfDeterminant;
    double aadfInverse[4][4];

    static double Det2x2( double a, double b, double c, double d )
    {
        return a*d - b*c;
    }

public:
    OCSTransformer( double adfNIn[3], bool bInverse = false ) :
        aadfInverse()
    {
        static const double dSmall = 1.0 / 64.0;
        static const double adfWZ[3] = { 0.0, 0.0, 1.0 };
        static const double adfWY[3] = { 0.0, 1.0, 0.0 };

        dfDeterminant = 0.0;
        Scale2Unit( adfNIn );
        memcpy( adfN, adfNIn, sizeof(double)*3 );

    if ((std::abs(adfN[0]) < dSmall) && (std::abs(adfN[1]) < dSmall))
            CrossProduct(adfWY, adfN, adfAX);
    else
            CrossProduct(adfWZ, adfN, adfAX);

    Scale2Unit( adfAX );
    CrossProduct(adfN, adfAX, adfAY);
    Scale2Unit( adfAY );

    if( bInverse == true ) {
        const double a[4] = { 0.0, adfAX[0], adfAY[0], adfN[0] };
        const double b[4] = { 0.0, adfAX[1], adfAY[1], adfN[1] };
        const double c[4] = { 0.0, adfAX[2], adfAY[2], adfN[2] };

        dfDeterminant = a[1]*b[2]*c[3] - a[1]*b[3]*c[2]
                      + a[2]*b[3]*c[1] - a[2]*b[1]*c[3]
                      + a[3]*b[1]*c[2] - a[3]*b[2]*c[1];

        if( dfDeterminant != 0.0 ) {
            const double k = 1.0 / dfDeterminant;
            const double a11 = adfAX[0];
            const double a12 = adfAY[0];
            const double a13 = adfN[0];
            const double a21 = adfAX[1];
            const double a22 = adfAY[1];
            const double a23 = adfN[1];
            const double a31 = adfAX[2];
            const double a32 = adfAY[2];
            const double a33 = adfN[2];

            aadfInverse[1][1] = k * Det2x2( a22,a23,a32,a33 );
            aadfInverse[1][2] = k * Det2x2( a13,a12,a33,a32 );
            aadfInverse[1][3] = k * Det2x2( a12,a13,a22,a23 );

            aadfInverse[2][1] = k * Det2x2( a23,a21,a33,a31 );
            aadfInverse[2][2] = k * Det2x2( a11,a13,a31,a33 );
            aadfInverse[2][3] = k * Det2x2( a13,a11,a23,a21 );

            aadfInverse[3][1] = k * Det2x2( a21,a22,a31,a32 );
            aadfInverse[3][2] = k * Det2x2( a12,a11,a32,a31 );
            aadfInverse[3][3] = k * Det2x2( a11,a12,a21,a22 );
        }
    }
    }

    static void CrossProduct(const double *a, const double *b, double *vResult) {
        vResult[0] = a[1] * b[2] - a[2] * b[1];
        vResult[1] = a[2] * b[0] - a[0] * b[2];
        vResult[2] = a[0] * b[1] - a[1] * b[0];
    }

    static void Scale2Unit(double* adfV) {
        double dfLen=sqrt(adfV[0]*adfV[0] + adfV[1]*adfV[1] + adfV[2]*adfV[2]);
        if (dfLen != 0)
        {
                adfV[0] /= dfLen;
                adfV[1] /= dfLen;
                adfV[2] /= dfLen;
        }
    }
    OGRSpatialReference *GetSourceCS() override { return NULL; }
    OGRSpatialReference *GetTargetCS() override { return NULL; }
    int Transform( int nCount,
                   double *x, double *y, double *z ) override
        { return TransformEx( nCount, x, y, z, NULL ); }

    int TransformEx( int nCount,
                     double *adfX, double *adfY, double *adfZ,
                     int *pabSuccess = NULL ) override
        {
            for( int i = 0; i < nCount; i++ )
            {
                const double x = adfX[i];
                const double y = adfY[i];
                const double z = adfZ[i];

                adfX[i] = x * adfAX[0] + y * adfAY[0] + z * adfN[0];
                adfY[i] = x * adfAX[1] + y * adfAY[1] + z * adfN[1];
                adfZ[i] = x * adfAX[2] + y * adfAY[2] + z * adfN[2];

                if( pabSuccess )
                    pabSuccess[i] = TRUE;
            }
            return TRUE;
        }

    int InverseTransform( int nCount,
                          double *adfX, double *adfY, double *adfZ )
    {
        if( dfDeterminant == 0.0 )
            return FALSE;

        for( int i = 0; i < nCount; i++ )
        {
            const double x = adfX[i];
            const double y = adfY[i];
            const double z = adfZ[i];

            adfX[i] = x * aadfInverse[1][1] + y * aadfInverse[1][2]
                    + z * aadfInverse[1][3];
            adfY[i] = x * aadfInverse[2][1] + y * aadfInverse[2][2]
                    + z * aadfInverse[2][3];
            adfZ[i] = x * aadfInverse[3][1] + y * aadfInverse[3][2]
                    + z * aadfInverse[3][3];
        }
        return TRUE;
    }
};

/************************************************************************/
/*                        ApplyOCSTransformer()                         */
/*                                                                      */
/*      Apply a transformation from OCS to world coordinates if an      */
/*      OCS vector was found in the object.                             */
/************************************************************************/

void OGRDXFLayer::ApplyOCSTransformer( OGRGeometry *poGeometry )

{
    if( oStyleProperties.count("210_N.dX") == 0
        || oStyleProperties.count("220_N.dY") == 0
        || oStyleProperties.count("230_N.dZ") == 0 )
        return;

    if( poGeometry == NULL )
        return;

    double adfN[3];

    adfN[0] = CPLAtof(oStyleProperties["210_N.dX"]);
    adfN[1] = CPLAtof(oStyleProperties["220_N.dY"]);
    adfN[2] = CPLAtof(oStyleProperties["230_N.dZ"]);

    OCSTransformer oTransformer( adfN );

    poGeometry->transform( &oTransformer );
}

/************************************************************************/
/*                            TextUnescape()                            */
/*                                                                      */
/*      Unexcape DXF style escape sequences such as \P for newline      */
/*      and \~ for space, and do the recoding to UTF8.                  */
/************************************************************************/

CPLString OGRDXFLayer::TextUnescape( const char *pszInput )

{
    return ACTextUnescape( pszInput, poDS->GetEncoding() );
}

/************************************************************************/
/*                           TranslateMTEXT()                           */
/************************************************************************/

OGRFeature *OGRDXFLayer::TranslateMTEXT()

{
    char szLineBuf[257];
    int nCode = 0;
    OGRFeature *poFeature = new OGRFeature( poFeatureDefn );
    double dfX = 0.0;
    double dfY = 0.0;
    double dfZ = 0.0;
    double dfAngle = 0.0;
    double dfHeight = 0.0;
    double dfXDirection = 0.0;
    double dfYDirection = 0.0;
    bool bHaveZ = false;
    int nAttachmentPoint = -1;
    CPLString osText;
    CPLString osStyleName = "Arial";

    while( (nCode = poDS->ReadValue(szLineBuf,sizeof(szLineBuf))) > 0 )
    {
        switch( nCode )
        {
          case 10:
            dfX = CPLAtof(szLineBuf);
            break;

          case 20:
            dfY = CPLAtof(szLineBuf);
            break;

          case 30:
            dfZ = CPLAtof(szLineBuf);
            bHaveZ = true;
            break;

          case 40:
            dfHeight = CPLAtof(szLineBuf);
            break;

          case 71:
            nAttachmentPoint = atoi(szLineBuf);
            break;

          case 11:
            dfXDirection = CPLAtof(szLineBuf);
            break;

          case 21:
            dfYDirection = CPLAtof(szLineBuf);
            dfAngle = atan2( dfYDirection, dfXDirection ) * 180.0 / M_PI;
            break;

          case 1:
          case 3:
            if( osText != "" )
                osText += "\n";
            osText += TextUnescape(szLineBuf);
            break;

          case 50:
            dfAngle = CPLAtof(szLineBuf);
            break;

          case 7:
            osStyleName = TextUnescape(szLineBuf);
            break;

          default:
            TranslateGenericProperty( poFeature, nCode, szLineBuf );
            break;
        }
    }
    if( nCode < 0 )
    {
        DXF_LAYER_READER_ERROR();
        delete poFeature;
        return NULL;
    }

    if( nCode == 0 )
        poDS->UnreadValue();

    OGRPoint* poGeom = NULL;
    if( bHaveZ )
        poGeom = new OGRPoint( dfX, dfY, dfZ );
    else
        poGeom = new OGRPoint( dfX, dfY );
    ApplyOCSTransformer( poGeom );
    poFeature->SetGeometryDirectly( poGeom );

/* -------------------------------------------------------------------- */
/*      Apply text after stripping off any extra terminating newline.   */
/* -------------------------------------------------------------------- */
    if( !osText.empty() && osText.back() == '\n' )
        osText.resize( osText.size() - 1 );

    poFeature->SetField( "Text", osText );

/* -------------------------------------------------------------------- */
/*      We need to escape double quotes with backslashes before they    */
/*      can be inserted in the style string.                            */
/* -------------------------------------------------------------------- */
    if( strchr( osText, '"') != NULL )
    {
        CPLString osEscaped;

        for( size_t iC = 0; iC < osText.size(); iC++ )
        {
            if( osText[iC] == '"' )
                osEscaped += "\\\"";
            else
                osEscaped += osText[iC];
        }
        osText = osEscaped;
    }

/* -------------------------------------------------------------------- */
/*      Work out the color for this feature.                            */
/* -------------------------------------------------------------------- */
    int nColor = 256;

    if( oStyleProperties.count("Color") > 0 )
        nColor = atoi(oStyleProperties["Color"]);

    // Use layer color?
    if( nColor < 1 || nColor > 255 )
    {
        CPLString osLayer = poFeature->GetFieldAsString("Layer");
        const char *pszValue = poDS->LookupLayerProperty( osLayer, "Color" );
        if( pszValue != NULL )
            nColor = atoi(pszValue);
    }

/* -------------------------------------------------------------------- */
/*      Prepare style string.                                           */
/* -------------------------------------------------------------------- */
    CPLString osStyle;
    char szBuffer[64];

    osStyle.Printf("LABEL(f:\"%s\",t:\"%s\"", osStyleName.c_str(), osText.c_str());

    if( dfAngle != 0.0 )
    {
        CPLsnprintf(szBuffer, sizeof(szBuffer), "%.3g", dfAngle);
        osStyle += CPLString().Printf(",a:%s", szBuffer);
    }

    if( dfHeight != 0.0 )
    {
        CPLsnprintf(szBuffer, sizeof(szBuffer), "%.3g", dfHeight);
        osStyle += CPLString().Printf(",s:%sg", szBuffer);
    }

    if( nAttachmentPoint >= 0 && nAttachmentPoint <= 9 )
    {
        const static int anAttachmentMap[10] =
            { -1, 7, 8, 9, 4, 5, 6, 1, 2, 3 };

        osStyle +=
            CPLString().Printf(",p:%d", anAttachmentMap[nAttachmentPoint]);
    }

    if( nColor > 0 && nColor < 256 )
    {
        const unsigned char *pabyDXFColors = ACGetColorTable();
        osStyle +=
            CPLString().Printf( ",c:#%02x%02x%02x",
                                pabyDXFColors[nColor*3+0],
                                pabyDXFColors[nColor*3+1],
                                pabyDXFColors[nColor*3+2] );
    }

    osStyle += ")";

    poFeature->SetStyleString( osStyle );

    return poFeature;
}

/************************************************************************/
/*                           TranslateTEXT()                            */
/************************************************************************/

OGRFeature *OGRDXFLayer::TranslateTEXT()

{
    char szLineBuf[257];
    int nCode = 0;
    OGRFeature *poFeature = new OGRFeature( poFeatureDefn );
    double dfX = 0.0;
    double dfY = 0.0;
    double dfZ = 0.0;
    double dfAngle = 0.0;
    double dfHeight = 0.0;
    CPLString osText;
    CPLString osStyleName = "Arial";
    bool bHaveZ = false;
    int nAnchorPosition = 1;
    int nHorizontalAlignment = 0;
    int nVerticalAlignment = 0;

    while( (nCode = poDS->ReadValue(szLineBuf,sizeof(szLineBuf))) > 0 )
    {
        switch( nCode )
        {
          case 10:
            dfX = CPLAtof(szLineBuf);
            break;

          case 20:
            dfY = CPLAtof(szLineBuf);
            break;

          case 30:
            dfZ = CPLAtof(szLineBuf);
            bHaveZ = true;
            break;

          case 40:
            dfHeight = CPLAtof(szLineBuf);
            break;

          case 1:
          // case 3:  // we used to capture prompt, but it should not be displayed as text.
            osText += szLineBuf;
            break;

          case 50:
            dfAngle = CPLAtof(szLineBuf);
            break;

          case 72:
            nHorizontalAlignment = atoi(szLineBuf);
            break;

          case 73:
            nVerticalAlignment = atoi(szLineBuf);
            break;

          case 7:
            osStyleName = TextUnescape(szLineBuf);
            break;
          
          default:
            TranslateGenericProperty( poFeature, nCode, szLineBuf );
            break;
        }
    }
    if( nCode < 0 )
    {
        DXF_LAYER_READER_ERROR();
        delete poFeature;
        return NULL;
    }

    if( nCode == 0 )
        poDS->UnreadValue();

    OGRPoint* poGeom = NULL;
    if( bHaveZ )
        poGeom = new OGRPoint( dfX, dfY, dfZ );
    else
        poGeom = new OGRPoint( dfX, dfY );
    ApplyOCSTransformer( poGeom );
    poFeature->SetGeometryDirectly( poGeom );

/* -------------------------------------------------------------------- */
/*      Determine anchor position.                                      */
/* -------------------------------------------------------------------- */
    if( nHorizontalAlignment > 0 || nVerticalAlignment > 0 )
    {
        switch( nVerticalAlignment )
        {
          case 1: // bottom
            nAnchorPosition = 10;
            break;

          case 2: // middle
            nAnchorPosition = 4;
            break;

          case 3: // top
            nAnchorPosition = 7;
            break;

          default:
            break;
        }
        if( nHorizontalAlignment < 3 )
            nAnchorPosition += nHorizontalAlignment;
        // TODO other alignment options
    }

/* -------------------------------------------------------------------- */
/*      Translate text from Win-1252 to UTF8.  We approximate this      */
/*      by treating Win-1252 as Latin-1.                                */
/* -------------------------------------------------------------------- */
    osText.Recode( poDS->GetEncoding(), CPL_ENC_UTF8 );

    poFeature->SetField( "Text", osText );

/* -------------------------------------------------------------------- */
/*      We need to escape double quotes with backslashes before they    */
/*      can be inserted in the style string.                            */
/* -------------------------------------------------------------------- */
    if( strchr( osText, '"') != NULL )
    {
        CPLString osEscaped;

        for( size_t iC = 0; iC < osText.size(); iC++ )
        {
            if( osText[iC] == '"' )
                osEscaped += "\\\"";
            else
                osEscaped += osText[iC];
        }
        osText = osEscaped;
    }

/* -------------------------------------------------------------------- */
/*      Is the layer disabled/hidden/frozen/off?                        */
/* -------------------------------------------------------------------- */
    CPLString osLayer = poFeature->GetFieldAsString("Layer");

    int bHidden =
        EQUAL(poDS->LookupLayerProperty( osLayer, "Hidden" ), "1");

/* -------------------------------------------------------------------- */
/*      Work out the color for this feature.                            */
/* -------------------------------------------------------------------- */
    int nColor = 256;

    if( oStyleProperties.count("Color") > 0 )
        nColor = atoi(oStyleProperties["Color"]);

    // Use layer color?
    if( nColor < 1 || nColor > 255 )
    {
        const char *pszValue = poDS->LookupLayerProperty( osLayer, "Color" );
        if( pszValue != NULL )
            nColor = atoi(pszValue);
    }

    if( nColor < 1 || nColor > 255 )
        nColor = 8;

/* -------------------------------------------------------------------- */
/*      Prepare style string.                                           */
/* -------------------------------------------------------------------- */
    CPLString osStyle;
    char szBuffer[64];

    osStyle.Printf("LABEL(f:\"%s\",t:\"%s\"", osStyleName.c_str(), osText.c_str());
    
    osStyle += CPLString().Printf(",p:%d", nAnchorPosition);

    if( dfAngle != 0.0 )
    {
        CPLsnprintf(szBuffer, sizeof(szBuffer), "%.3g", dfAngle);
        osStyle += CPLString().Printf(",a:%s", szBuffer);
    }

    if( dfHeight != 0.0 )
    {
        CPLsnprintf(szBuffer, sizeof(szBuffer), "%.3g", dfHeight);
        osStyle += CPLString().Printf(",s:%sg", szBuffer);
    }

    const unsigned char *pabyDWGColors = ACGetColorTable();

    snprintf( szBuffer, sizeof(szBuffer), ",c:#%02x%02x%02x",
              pabyDWGColors[nColor*3+0],
              pabyDWGColors[nColor*3+1],
              pabyDWGColors[nColor*3+2] );
    osStyle += szBuffer;

    if( bHidden )
        osStyle += "00";

    osStyle += ")";

    poFeature->SetStyleString( osStyle );

    return poFeature;
}

/************************************************************************/
/*                           TranslatePOINT()                           */
/************************************************************************/

OGRFeature *OGRDXFLayer::TranslatePOINT()

{
    char szLineBuf[257];
    int nCode = 0;
    OGRFeature *poFeature = new OGRFeature( poFeatureDefn );
    double dfX = 0.0;
    double dfY = 0.0;
    double dfZ = 0.0;
    bool bHaveZ = false;

    while( (nCode = poDS->ReadValue(szLineBuf,sizeof(szLineBuf))) > 0 )
    {
        switch( nCode )
        {
          case 10:
            dfX = CPLAtof(szLineBuf);
            break;

          case 20:
            dfY = CPLAtof(szLineBuf);
            break;

          case 30:
            dfZ = CPLAtof(szLineBuf);
            bHaveZ = true;
            break;

          default:
            TranslateGenericProperty( poFeature, nCode, szLineBuf );
            break;
        }
    }
    if( nCode < 0 )
    {
        DXF_LAYER_READER_ERROR();
        delete poFeature;
        return NULL;
    }

    if( nCode == 0 )
        poDS->UnreadValue();

    OGRPoint* poGeom = NULL;
    if( bHaveZ )
        poGeom = new OGRPoint( dfX, dfY, dfZ );
    else
        poGeom = new OGRPoint( dfX, dfY );

    poFeature->SetGeometryDirectly( poGeom );

    // Set style pen color
    PrepareLineStyle( poFeature );

    return poFeature;
}

/************************************************************************/
/*                           TranslateLINE()                            */
/************************************************************************/

OGRFeature *OGRDXFLayer::TranslateLINE()

{
    char szLineBuf[257];
    int nCode = 0;
    OGRFeature *poFeature = new OGRFeature( poFeatureDefn );
    double dfX1 = 0.0;
    double dfY1 = 0.0;
    double dfZ1 = 0.0;
    double dfX2 = 0.0;
    double dfY2 = 0.0;
    double dfZ2 = 0.0;
    bool bHaveZ = false;

/* -------------------------------------------------------------------- */
/*      Process values.                                                 */
/* -------------------------------------------------------------------- */
    while( (nCode = poDS->ReadValue(szLineBuf,sizeof(szLineBuf))) > 0 )
    {
        switch( nCode )
        {
          case 10:
            dfX1 = CPLAtof(szLineBuf);
            break;

          case 11:
            dfX2 = CPLAtof(szLineBuf);
            break;

          case 20:
            dfY1 = CPLAtof(szLineBuf);
            break;

          case 21:
            dfY2 = CPLAtof(szLineBuf);
            break;

          case 30:
            dfZ1 = CPLAtof(szLineBuf);
            bHaveZ = true;
            break;

          case 31:
            dfZ2 = CPLAtof(szLineBuf);
            bHaveZ = true;
            break;

          default:
            TranslateGenericProperty( poFeature, nCode, szLineBuf );
            break;
        }
    }
    if( nCode < 0 )
    {
        DXF_LAYER_READER_ERROR();
        delete poFeature;
        return NULL;
    }

    if( nCode == 0 )
        poDS->UnreadValue();

/* -------------------------------------------------------------------- */
/*      Create geometry                                                 */
/* -------------------------------------------------------------------- */
    OGRLineString *poLS = new OGRLineString();
    if( bHaveZ )
    {
        poLS->addPoint( dfX1, dfY1, dfZ1 );
        poLS->addPoint( dfX2, dfY2, dfZ2 );
    }
    else
    {
        poLS->addPoint( dfX1, dfY1 );
        poLS->addPoint( dfX2, dfY2 );
    }

    poFeature->SetGeometryDirectly( poLS );

    PrepareLineStyle( poFeature );

    return poFeature;
}

/************************************************************************/
/*                         TranslateLWPOLYLINE()                        */
/************************************************************************/
OGRFeature *OGRDXFLayer::TranslateLWPOLYLINE()

{
    // Collect vertices and attributes into a smooth polyline.
    // If there are no bulges, then we are a straight-line polyline.
    // Single-vertex polylines become points.
    // Group code 30 (vertex Z) is not part of this entity.
    char szLineBuf[257];
    int nCode = 0;
    int nPolylineFlag = 0;

    OGRFeature *poFeature = new OGRFeature( poFeatureDefn );
    double dfX = 0.0;
    double dfY = 0.0;
    double dfZ = 0.0;
    bool bHaveX = false;
    bool bHaveY = false;

    int nNumVertices = 1;   // use 1 based index
    int npolyarcVertexCount = 1;
    double dfBulge = 0.0;
    DXFSmoothPolyline smoothPolyline;

    smoothPolyline.setCoordinateDimension(2);

/* -------------------------------------------------------------------- */
/*      Collect information from the LWPOLYLINE object itself.          */
/* -------------------------------------------------------------------- */
    while( (nCode = poDS->ReadValue(szLineBuf,sizeof(szLineBuf))) > 0 )
    {
        if(npolyarcVertexCount > nNumVertices)
        {
            CPLError( CE_Failure, CPLE_AppDefined,
                      "Too many vertices found in LWPOLYLINE." );
            delete poFeature;
            return NULL;
        }

        switch( nCode )
        {
          case 38:
            // Constant elevation.
            dfZ = CPLAtof(szLineBuf);
            smoothPolyline.setCoordinateDimension(3);
            break;

          case 90:
            nNumVertices = atoi(szLineBuf);
            break;

          case 70:
            nPolylineFlag = atoi(szLineBuf);
            break;

          case 10:
            if( bHaveX && bHaveY )
            {
                smoothPolyline.AddPoint(dfX, dfY, dfZ, dfBulge);
                npolyarcVertexCount++;
                dfBulge = 0.0;
                bHaveY = false;
            }
            dfX = CPLAtof(szLineBuf);
            bHaveX = true;
            break;

          case 20:
            if( bHaveX && bHaveY )
            {
                smoothPolyline.AddPoint( dfX, dfY, dfZ, dfBulge );
                npolyarcVertexCount++;
                dfBulge = 0.0;
                bHaveX = false;
            }
            dfY = CPLAtof(szLineBuf);
            bHaveY = true;
            break;

          case 42:
            dfBulge = CPLAtof(szLineBuf);
            break;

          default:
            TranslateGenericProperty( poFeature, nCode, szLineBuf );
            break;
        }
    }
    if( nCode < 0 )
    {
        DXF_LAYER_READER_ERROR();
        delete poFeature;
        return NULL;
    }

    if( nCode == 0 )
        poDS->UnreadValue();

    if( bHaveX && bHaveY )
        smoothPolyline.AddPoint(dfX, dfY, dfZ, dfBulge);

    if(smoothPolyline.IsEmpty())
    {
        delete poFeature;
        return NULL;
    }

/* -------------------------------------------------------------------- */
/*      Close polyline if necessary.                                    */
/* -------------------------------------------------------------------- */
    if(nPolylineFlag & 0x01)
        smoothPolyline.Close();

    OGRGeometry* poGeom = smoothPolyline.Tesselate();
    ApplyOCSTransformer( poGeom );
    poFeature->SetGeometryDirectly( poGeom );

    PrepareLineStyle( poFeature );

    return poFeature;
}

/************************************************************************/
/*                         TranslatePOLYLINE()                          */
/*                                                                      */
/*      We also capture the following VERTEXes.                         */
/************************************************************************/

OGRFeature *OGRDXFLayer::TranslatePOLYLINE()

{
    char szLineBuf[257];
    int nCode = 0;
    int nPolylineFlag = 0;
    OGRFeature *poFeature = new OGRFeature( poFeatureDefn );

/* -------------------------------------------------------------------- */
/*      Collect information from the POLYLINE object itself.            */
/* -------------------------------------------------------------------- */
    while( (nCode = poDS->ReadValue(szLineBuf,sizeof(szLineBuf))) > 0 )
    {
        switch( nCode )
        {
          case 70:
            nPolylineFlag = atoi(szLineBuf);
            break;

          default:
            TranslateGenericProperty( poFeature, nCode, szLineBuf );
            break;
        }
    }
    if( nCode < 0 )
    {
        DXF_LAYER_READER_ERROR();
        delete poFeature;
        return NULL;
    }

    if( (nPolylineFlag & 16) != 0 )
    {
        CPLDebug( "DXF", "Polygon mesh not supported." );
        delete poFeature;
        return NULL;
    }

/* -------------------------------------------------------------------- */
/*      Collect VERTEXes as a smooth polyline.                          */
/* -------------------------------------------------------------------- */
    double dfX = 0.0;
    double dfY = 0.0;
    double dfZ = 0.0;
    double dfBulge = 0.0;
    int nVertexFlag = 0;
    DXFSmoothPolyline   smoothPolyline;
    int                 vertexIndex71 = 0;
    int                 vertexIndex72 = 0;
    int                 vertexIndex73 = 0;
    int                 vertexIndex74 = 0;
    OGRPoint **papoPoints = NULL;
    int nPoints = 0;
    OGRPolyhedralSurface *poPS = new OGRPolyhedralSurface();

    smoothPolyline.setCoordinateDimension(2);

    while( nCode == 0 && !EQUAL(szLineBuf,"SEQEND") )
    {
        // Eat non-vertex objects.
        if( !EQUAL(szLineBuf,"VERTEX") )
        {
            while( (nCode = poDS->ReadValue(szLineBuf,sizeof(szLineBuf)))>0 ) {}
            if( nCode < 0 )
            {
                DXF_LAYER_READER_ERROR();
                delete poFeature;
                delete poPS;
                // delete the list of points
                for (int i = 0; i < nPoints; i++)
                    delete papoPoints[i];
                CPLFree(papoPoints);

                return NULL;
            }

            continue;
        }

        // process a Vertex
        while( (nCode = poDS->ReadValue(szLineBuf,sizeof(szLineBuf))) > 0 )
        {
            switch( nCode )
            {
              case 10:
                dfX = CPLAtof(szLineBuf);
                break;

              case 20:
                dfY = CPLAtof(szLineBuf);
                break;

              case 30:
                dfZ = CPLAtof(szLineBuf);
                smoothPolyline.setCoordinateDimension(3);
                break;

              case 42:
                dfBulge = CPLAtof(szLineBuf);
                break;

              case 70:
                nVertexFlag = atoi(szLineBuf);
                break;

              case 71:
                vertexIndex71 = atoi(szLineBuf);
                break;

              case 72:
                vertexIndex72 = atoi(szLineBuf);
                break;

              case 73:
                vertexIndex73 = atoi(szLineBuf);
                break;

              case 74:
                vertexIndex74 = atoi(szLineBuf);
                break;

              default:
                break;
            }
        }

        if (((nVertexFlag & 64) != 0) && ((nVertexFlag & 128) != 0))
        {
            // add the point to the list of points
            OGRPoint *poPoint = new OGRPoint(dfX, dfY, dfZ);
            OGRPoint** papoNewPoints = (OGRPoint **) VSI_REALLOC_VERBOSE( papoPoints,
                                                     sizeof(void*) * (nPoints+1) );

            papoPoints = papoNewPoints;
            papoPoints[nPoints] = poPoint;
            nPoints++;
        }

        // Note - If any index out of vertexIndex71, vertexIndex72, vertexIndex73 or vertexIndex74
        // is negative, it means that the line starting from that vertex is invisible

        if (nVertexFlag == 128 && papoPoints != NULL)
        {
            // create a polygon and add it to the Polyhedral Surface
            OGRLinearRing *poLR = new OGRLinearRing();
            int iPoint = 0;
            int startPoint = -1;
            poLR->set3D(TRUE);
            if (vertexIndex71 > 0 && vertexIndex71 <= nPoints)
            {
                if (startPoint == -1)
                    startPoint = vertexIndex71-1;
                poLR->setPoint(iPoint,papoPoints[vertexIndex71-1]);
                iPoint++;
                vertexIndex71 = 0;
            }
            if (vertexIndex72 > 0 && vertexIndex72 <= nPoints)
            {
                if (startPoint == -1)
                    startPoint = vertexIndex72-1;
                poLR->setPoint(iPoint,papoPoints[vertexIndex72-1]);
                iPoint++;
                vertexIndex72 = 0;
            }
            if (vertexIndex73 > 0 && vertexIndex73 <= nPoints)
            {
                if (startPoint == -1)
                    startPoint = vertexIndex73-1;
                poLR->setPoint(iPoint,papoPoints[vertexIndex73-1]);
                iPoint++;
                vertexIndex73 = 0;
            }
            if (vertexIndex74 > 0 && vertexIndex74 <= nPoints)
            {
                if (startPoint == -1)
                    startPoint = vertexIndex74-1;
                poLR->setPoint(iPoint,papoPoints[vertexIndex74-1]);
                iPoint++;
                vertexIndex74 = 0;
            }

            // complete the ring
            poLR->setPoint(iPoint,papoPoints[startPoint]);

            OGRPolygon *poPolygon = new OGRPolygon();
            poPolygon->addRing((OGRCurve *)poLR);

            poPS->addGeometryDirectly(poPolygon);

            // delete the ring to prevent leakage
            delete poLR;
        }

        if( nCode < 0 )
        {
            DXF_LAYER_READER_ERROR();
            delete poFeature;
            delete poPS;
            // delete the list of points
            for (int i = 0; i < nPoints; i++)
                delete papoPoints[i];
            CPLFree(papoPoints);
            return NULL;
        }

        // Ignore Spline frame control points ( see #4683 )
        if ((nVertexFlag & 16) == 0)
            smoothPolyline.AddPoint( dfX, dfY, dfZ, dfBulge );
        dfBulge = 0.0;
    }

    // delete the list of points
    for (int i = 0; i < nPoints; i++)
        delete papoPoints[i];
    CPLFree(papoPoints);

    if(smoothPolyline.IsEmpty())
    {
        delete poFeature;
        delete poPS;
        return NULL;
    }

    if (poPS->getNumGeometries() > 0)
    {
        poFeature->SetGeometryDirectly((OGRGeometry *)poPS);
        return poFeature;
    }

    else
        delete poPS;

    /* -------------------------------------------------------------------- */
    /*      Close polyline if necessary.                                    */
    /* -------------------------------------------------------------------- */
    if(nPolylineFlag & 0x01)
        smoothPolyline.Close();

    OGRGeometry* poGeom = smoothPolyline.Tesselate();

    if( (nPolylineFlag & 8) == 0 )
        ApplyOCSTransformer( poGeom );
    poFeature->SetGeometryDirectly( poGeom );

    PrepareLineStyle( poFeature );

    return poFeature;
}

/************************************************************************/
/*                          TranslateCIRCLE()                           */
/************************************************************************/

OGRFeature *OGRDXFLayer::TranslateCIRCLE()

{
    char szLineBuf[257];
    int nCode = 0;
    OGRFeature *poFeature = new OGRFeature( poFeatureDefn );
    double dfX1 = 0.0;
    double dfY1 = 0.0;
    double dfZ1 = 0.0;
    double dfRadius = 0.0;
    bool bHaveZ = false;

/* -------------------------------------------------------------------- */
/*      Process values.                                                 */
/* -------------------------------------------------------------------- */
    while( (nCode = poDS->ReadValue(szLineBuf,sizeof(szLineBuf))) > 0 )
    {
        switch( nCode )
        {
          case 10:
            dfX1 = CPLAtof(szLineBuf);
            break;

          case 20:
            dfY1 = CPLAtof(szLineBuf);
            break;

          case 30:
            dfZ1 = CPLAtof(szLineBuf);
            bHaveZ = true;
            break;

          case 40:
            dfRadius = CPLAtof(szLineBuf);
            break;

          default:
            TranslateGenericProperty( poFeature, nCode, szLineBuf );
            break;
        }
    }
    if( nCode < 0 )
    {
        DXF_LAYER_READER_ERROR();
        delete poFeature;
        return NULL;
    }

    if( nCode == 0 )
        poDS->UnreadValue();

/* -------------------------------------------------------------------- */
/*      Create geometry                                                 */
/* -------------------------------------------------------------------- */
    OGRGeometry *poCircle =
        OGRGeometryFactory::approximateArcAngles( dfX1, dfY1, dfZ1,
                                                  dfRadius, dfRadius, 0.0,
                                                  0.0, 360.0,
                                                  0.0 );

    if( !bHaveZ )
        poCircle->flattenTo2D();

    ApplyOCSTransformer( poCircle );
    poFeature->SetGeometryDirectly( poCircle );
    PrepareLineStyle( poFeature );

    return poFeature;
}

/************************************************************************/
/*                          TranslateELLIPSE()                          */
/************************************************************************/

OGRFeature *OGRDXFLayer::TranslateELLIPSE()

{
    char szLineBuf[257];
    int nCode = 0;
    OGRFeature *poFeature = new OGRFeature( poFeatureDefn );
    double dfX1 = 0.0;
    double dfY1 = 0.0;
    double dfZ1 = 0.0;
    double dfRatio = 0.0;
    double dfStartAngle = 0.0;
    double dfEndAngle = 360.0;
    double dfAxisX = 0.0;
    double dfAxisY = 0.0;
    double dfAxisZ=0.0;
    bool bHaveZ = false;
    bool bApplyOCSTransform = false;

/* -------------------------------------------------------------------- */
/*      Process values.                                                 */
/* -------------------------------------------------------------------- */
    while( (nCode = poDS->ReadValue(szLineBuf,sizeof(szLineBuf))) > 0 )
    {
        switch( nCode )
        {
          case 10:
            dfX1 = CPLAtof(szLineBuf);
            break;

          case 20:
            dfY1 = CPLAtof(szLineBuf);
            break;

          case 30:
            dfZ1 = CPLAtof(szLineBuf);
            bHaveZ = true;
            break;

          case 11:
            dfAxisX = CPLAtof(szLineBuf);
            break;

          case 21:
            dfAxisY = CPLAtof(szLineBuf);
            break;

          case 31:
            dfAxisZ = CPLAtof(szLineBuf);
            break;

          case 40:
            dfRatio = CPLAtof(szLineBuf);
            break;

          case 41:
            // These *seem* to always be in radians regardless of $AUNITS
            dfEndAngle = -1 * CPLAtof(szLineBuf) * 180.0 / M_PI;
            break;

          case 42:
            // These *seem* to always be in radians regardless of $AUNITS
            dfStartAngle = -1 * CPLAtof(szLineBuf) * 180.0 / M_PI;
            break;

          default:
            TranslateGenericProperty( poFeature, nCode, szLineBuf );
            break;
        }
    }
    if( nCode < 0 )
    {
        DXF_LAYER_READER_ERROR();
        delete poFeature;
        return NULL;
    }

    if( nCode == 0 )
        poDS->UnreadValue();

/* -------------------------------------------------------------------- */
/*      Setup coordinate system                                         */
/* -------------------------------------------------------------------- */
    if( oStyleProperties.count("210_N.dX") != 0
        && oStyleProperties.count("220_N.dY") != 0
        && oStyleProperties.count("230_N.dZ") != 0 )
    {
        double adfN[3] = {
            CPLAtof(oStyleProperties["210_N.dX"]),
            CPLAtof(oStyleProperties["220_N.dY"]),
            CPLAtof(oStyleProperties["230_N.dZ"])
        };

        if( (adfN[0] == 0.0 && adfN[1] == 0.0 && adfN[2] == 1.0) == false )
        {
            OCSTransformer oTransformer( adfN, true );

            bApplyOCSTransform = true;

            double *x = &dfX1;
            double *y = &dfY1;
            double *z = &dfZ1;
            oTransformer.InverseTransform( 1, x, y, z );

            x = &dfAxisX;
            y = &dfAxisY;
            z = &dfAxisZ;
            oTransformer.InverseTransform( 1, x, y, z );
        }
    }

/* -------------------------------------------------------------------- */
/*      Compute primary and secondary axis lengths, and the angle of    */
/*      rotation for the ellipse.                                       */
/* -------------------------------------------------------------------- */
    double dfPrimaryRadius = sqrt( dfAxisX * dfAxisX
                            + dfAxisY * dfAxisY
                            + dfAxisZ * dfAxisZ );

    double dfSecondaryRadius = dfRatio * dfPrimaryRadius;

    double dfRotation = -1 * atan2( dfAxisY, dfAxisX ) * 180 / M_PI;

/* -------------------------------------------------------------------- */
/*      Create geometry                                                 */
/* -------------------------------------------------------------------- */
    if( dfStartAngle > dfEndAngle )
        dfEndAngle += 360.0;

    OGRGeometry *poEllipse =
        OGRGeometryFactory::approximateArcAngles( dfX1, dfY1, dfZ1,
                                                  dfPrimaryRadius,
                                                  dfSecondaryRadius,
                                                  dfRotation,
                                                  dfStartAngle, dfEndAngle,
                                                  0.0 );

    if( !bHaveZ )
        poEllipse->flattenTo2D();

    if( bApplyOCSTransform == true )
        ApplyOCSTransformer( poEllipse );
    poFeature->SetGeometryDirectly( poEllipse );

    PrepareLineStyle( poFeature );

    return poFeature;
}

/************************************************************************/
/*                            TranslateARC()                            */
/************************************************************************/

OGRFeature *OGRDXFLayer::TranslateARC()

{
    char szLineBuf[257];
    int nCode = 0;
    OGRFeature *poFeature = new OGRFeature( poFeatureDefn );
    double dfX1 = 0.0;
    double dfY1 = 0.0;
    double dfZ1 = 0.0;
    double dfRadius = 0.0;
    double dfStartAngle = 0.0;
    double dfEndAngle = 360.0;
    bool bHaveZ = false;

/* -------------------------------------------------------------------- */
/*      Process values.                                                 */
/* -------------------------------------------------------------------- */
    while( (nCode = poDS->ReadValue(szLineBuf,sizeof(szLineBuf))) > 0 )
    {
        switch( nCode )
        {
          case 10:
            dfX1 = CPLAtof(szLineBuf);
            break;

          case 20:
            dfY1 = CPLAtof(szLineBuf);
            break;

          case 30:
            dfZ1 = CPLAtof(szLineBuf);
            bHaveZ = true;
            break;

          case 40:
            dfRadius = CPLAtof(szLineBuf);
            break;

          case 50:
            // This is apparently always degrees regardless of AUNITS
            dfEndAngle = -1 * CPLAtof(szLineBuf);
            break;

          case 51:
            // This is apparently always degrees regardless of AUNITS
            dfStartAngle = -1 * CPLAtof(szLineBuf);
            break;

          default:
            TranslateGenericProperty( poFeature, nCode, szLineBuf );
            break;
        }
    }
    if( nCode < 0 )
    {
        DXF_LAYER_READER_ERROR();
        delete poFeature;
        return NULL;
    }

    if( nCode == 0 )
        poDS->UnreadValue();

/* -------------------------------------------------------------------- */
/*      Create geometry                                                 */
/* -------------------------------------------------------------------- */
    if( dfStartAngle > dfEndAngle )
        dfEndAngle += 360.0;

    OGRGeometry *poArc =
        OGRGeometryFactory::approximateArcAngles( dfX1, dfY1, dfZ1,
                                                  dfRadius, dfRadius, 0.0,
                                                  dfStartAngle, dfEndAngle,
                                                  0.0 );
    if( !bHaveZ )
        poArc->flattenTo2D();

    ApplyOCSTransformer( poArc );
    poFeature->SetGeometryDirectly( poArc );

    PrepareLineStyle( poFeature );

    return poFeature;
}

/************************************************************************/
/*                          TranslateSPLINE()                           */
/************************************************************************/

void rbspline2(int npts,int k,int p1,double b[],double h[],
        bool bCalculateKnots, double knots[], double p[]);

OGRFeature *OGRDXFLayer::TranslateSPLINE()

{
    char szLineBuf[257];
    int nCode;
    int nDegree = -1;
    int nOrder = -1;
    int i;
    int nControlPoints = -1;
    int nKnots = -1;
    bool bResult = false;
    bool bCalculateKnots = false;
    OGRFeature *poFeature = new OGRFeature( poFeatureDefn );
    std::vector<double> adfControlPoints;
    std::vector<double> adfKnots;
    std::vector<double> adfWeights;

    adfControlPoints.push_back(0.0);
    adfKnots.push_back(0.0);
    adfWeights.push_back(0.0);

/* -------------------------------------------------------------------- */
/*      Process values.                                                 */
/* -------------------------------------------------------------------- */
    while( (nCode = poDS->ReadValue(szLineBuf,sizeof(szLineBuf))) > 0 )
    {
        switch( nCode )
        {
          case 10:
            adfControlPoints.push_back( CPLAtof(szLineBuf) );
            break;

          case 20:
            adfControlPoints.push_back( CPLAtof(szLineBuf) );
            adfControlPoints.push_back( 0.0 );
            break;

          case 40:
            adfKnots.push_back( CPLAtof(szLineBuf) );
            break;

          case 41:
            adfWeights.push_back( CPLAtof(szLineBuf) );
            break;

          case 70:
            break;

          case 71:
            nDegree = atoi(szLineBuf);
            break;

          case 72:
            nKnots = atoi(szLineBuf);
            break;

          case 73:
            nControlPoints = atoi(szLineBuf);
            break;

          default:
            TranslateGenericProperty( poFeature, nCode, szLineBuf );
            break;
        }
    }
    if( nCode < 0 )
    {
        DXF_LAYER_READER_ERROR();
        delete poFeature;
        return NULL;
    }

    if( nCode == 0 )
        poDS->UnreadValue();

/* -------------------------------------------------------------------- */
/*      Sanity checks                                                   */
/* -------------------------------------------------------------------- */
    nOrder = nDegree + 1;

    bResult = ( nOrder >= 2 );
    if( bResult == true )
    {
        // Check whether nctrlpts value matches number of vertices read
        int nCheck = (static_cast<int>(adfControlPoints.size()) - 1) / 3;

        if( nControlPoints == -1 )
            nControlPoints =
                (static_cast<int>(adfControlPoints.size()) - 1) / 3;

        // min( num(ctrlpts) ) = order
        bResult = ( nControlPoints >= nOrder && nControlPoints == nCheck);
    }

    if( bResult == true )
    {
        int nCheck = static_cast<int>(adfKnots.size()) - 1;

        // Recalculate knots when:
        // - no knots data present, nknots is -1 and ncheck is 0
        // - nknots value present, no knot vertices
        //   nknots is (nctrlpts + order), ncheck is 0
        if( nCheck == 0 )
        {
            bCalculateKnots = true;
            for( i = 0; i < (nControlPoints + nOrder); i++ )
                adfKnots.push_back( 0.0 );

            nCheck = static_cast<int>(adfKnots.size()) - 1;
        }
        // Adjust nknots value when:
        // - nknots value not present, knot vertices present
        //   nknots is -1, ncheck is (nctrlpts + order)
        if( nKnots == -1 )
            nKnots = static_cast<int>(adfKnots.size()) - 1;

        // num(knots) = num(ctrlpts) + order
        bResult = ( nKnots == (nControlPoints + nOrder) && nKnots == nCheck );
    }

    if( bResult == true )
    {
        int nWeights = static_cast<int>(adfWeights.size()) - 1;

        if( nWeights == 0 )
        {
            for( i = 0; i < nControlPoints; i++ )
                adfWeights.push_back( 1.0 );

            nWeights = static_cast<int>(adfWeights.size()) - 1;
        }

        // num(weights) = num(ctrlpts)
        bResult = ( nWeights == nControlPoints );
    }

    if( bResult == false )
    {
        DXF_LAYER_READER_ERROR();
        delete poFeature;
        return NULL;
    }

/* -------------------------------------------------------------------- */
/*      Interpolate spline                                              */
/* -------------------------------------------------------------------- */
    int p1 = nControlPoints * 8;
    std::vector<double> p;

    p.push_back( 0.0 );
    for( i = 0; i < 3*p1; i++ )
        p.push_back( 0.0 );

    rbspline2( nControlPoints, nOrder, p1, &(adfControlPoints[0]),
            &(adfWeights[0]), bCalculateKnots, &(adfKnots[0]), &(p[0]) );

/* -------------------------------------------------------------------- */
/*      Turn into OGR geometry.                                         */
/* -------------------------------------------------------------------- */
    OGRLineString *poLS = new OGRLineString();

    poLS->setNumPoints( p1 );
    for( i = 0; i < p1; i++ )
        poLS->setPoint( i, p[i*3+1], p[i*3+2] );

    poFeature->SetGeometryDirectly( poLS );

    PrepareLineStyle( poFeature );

    return poFeature;
}

/************************************************************************/
/*                          Translate3DFACE()                           */
/************************************************************************/

OGRFeature *OGRDXFLayer::Translate3DFACE()

{
    char szLineBuf[257];
    int nCode = 0;
    OGRFeature *poFeature = new OGRFeature( poFeatureDefn );
    double dfX1 = 0.0;
    double dfY1 = 0.0;
    double dfZ1 = 0.0;
    double dfX2 = 0.0;
    double dfY2 = 0.0;
    double dfZ2 = 0.0;
    double dfX3 = 0.0;
    double dfY3 = 0.0;
    double dfZ3 = 0.0;
    double dfX4 = 0.0;
    double dfY4 = 0.0;
    double dfZ4 = 0.0;

/* -------------------------------------------------------------------- */
/*      Process values.                                                 */
/* -------------------------------------------------------------------- */
    while( (nCode = poDS->ReadValue(szLineBuf,sizeof(szLineBuf))) > 0 )
    {
        switch( nCode )
        {
          case 10:
            dfX1 = CPLAtof(szLineBuf);
            break;

          case 11:
            dfX2 = CPLAtof(szLineBuf);
            break;

          case 12:
            dfX3 = CPLAtof(szLineBuf);
            break;

          case 13:
            dfX4 = CPLAtof(szLineBuf);
            break;

          case 20:
            dfY1 = CPLAtof(szLineBuf);
            break;

          case 21:
            dfY2 = CPLAtof(szLineBuf);
            break;

          case 22:
            dfY3 = CPLAtof(szLineBuf);
            break;

          case 23:
            dfY4 = CPLAtof(szLineBuf);
            break;

          case 30:
            dfZ1 = CPLAtof(szLineBuf);
            break;

          case 31:
            dfZ2 = CPLAtof(szLineBuf);
            break;

          case 32:
            dfZ3 = CPLAtof(szLineBuf);
            break;

          case 33:
            dfZ4 = CPLAtof(szLineBuf);
            break;

          default:
            TranslateGenericProperty( poFeature, nCode, szLineBuf );
            break;
        }
    }
    if( nCode < 0 )
    {
        DXF_LAYER_READER_ERROR();
        delete poFeature;
        return NULL;
    }

    if( nCode == 0 )
        poDS->UnreadValue();

/* -------------------------------------------------------------------- */
/*      Create geometry                                                 */
/* -------------------------------------------------------------------- */
    OGRPolygon *poPoly = new OGRPolygon();
    OGRLinearRing* poLR = new OGRLinearRing();
    poLR->addPoint( dfX1, dfY1, dfZ1 );
    poLR->addPoint( dfX2, dfY2, dfZ2 );
    poLR->addPoint( dfX3, dfY3, dfZ3 );
    if( dfX4 != dfX3 || dfY4 != dfY3 || dfZ4 != dfZ3 )
        poLR->addPoint( dfX4, dfY4, dfZ4 );
    poPoly->addRingDirectly(poLR);
    poPoly->closeRings();

    ApplyOCSTransformer( poLR );
    poFeature->SetGeometryDirectly( poPoly );

    /* PrepareLineStyle( poFeature ); */

    return poFeature;
}

/* -------------------------------------------------------------------- */
/*      Distance                                                        */
/*                                                                      */
/*      Calculate distance between two points                           */
/* -------------------------------------------------------------------- */

static double Distance(double dX0, double dY0, double dX1, double dY1) {
    return sqrt((dX1 - dX0) * (dX1 - dX0) + (dY1 - dY0) * (dY1 - dY0));
}

/* -------------------------------------------------------------------- */
/*      AddEdgesByNearest                                               */
/*                                                                      */
/*      Order and add SOLID edges to geometry collection                */
/* -------------------------------------------------------------------- */

static void AddEdgesByNearest(OGRGeometryCollection* poCollection, OGRLineString *poLS,
        OGRLineString *poLS4, double dfX2, double dfY2, double dfX3,
        double dfY3, double dfX4, double dfY4) {
    OGRLineString *poLS2 = new OGRLineString();
    OGRLineString *poLS3 = new OGRLineString();
    poLS->addPoint(dfX2, dfY2);
    poCollection->addGeometryDirectly(poLS);
    poLS2->addPoint(dfX2, dfY2);
    double dTo3 = Distance(dfX2, dfY2, dfX3, dfY3);
    double dTo4 = Distance(dfX2, dfY2, dfX4, dfY4);
    if (dTo3 <= dTo4) {
        poLS2->addPoint(dfX3, dfY3);
        poCollection->addGeometryDirectly(poLS2);
        poLS3->addPoint(dfX3, dfY3);
        poLS3->addPoint(dfX4, dfY4);
        poCollection->addGeometryDirectly(poLS3);
        poLS4->addPoint(dfX4, dfY4);
    } else {
        poLS2->addPoint(dfX4, dfY4);
        poCollection->addGeometryDirectly(poLS2);
        poLS3->addPoint(dfX4, dfY4);
        poLS3->addPoint(dfX3, dfY3);
        poCollection->addGeometryDirectly(poLS3);
        poLS4->addPoint(dfX3, dfY3);
    }
}

/************************************************************************/
/*                           TranslateSOLID()                           */
/************************************************************************/

OGRFeature *OGRDXFLayer::TranslateSOLID()

{
    CPLDebug("SOLID", "translating solid");
    char szLineBuf[257];
    int nCode = 0;
    OGRFeature *poFeature = new OGRFeature(poFeatureDefn);
    double dfX1 = 0.0;
    double dfY1 = 0.0;
    double dfX2 = 0.0;
    double dfY2 = 0.0;
    double dfX3 = 0.0;
    double dfY3 = 0.0;
    double dfX4 = 0.0;
    double dfY4 = 0.0;

    while ((nCode = poDS->ReadValue(szLineBuf, sizeof(szLineBuf))) > 0) {
        switch (nCode) {
        case 10:
            dfX1 = CPLAtof(szLineBuf);
            break;

        case 20:
            dfY1 = CPLAtof(szLineBuf);
            break;

        case 30:
            break;

        case 11:
            dfX2 = CPLAtof(szLineBuf);
            break;

        case 21:
            dfY2 = CPLAtof(szLineBuf);
            break;

        case 31:
            break;

        case 12:
            dfX3 = CPLAtof(szLineBuf);
            break;

        case 22:
            dfY3 = CPLAtof(szLineBuf);
            break;

        case 32:
            break;

        case 13:
            dfX4 = CPLAtof(szLineBuf);
            break;

        case 23:
            dfY4 = CPLAtof(szLineBuf);
            break;

        case 33:
            break;

        default:
            TranslateGenericProperty(poFeature, nCode, szLineBuf);
            break;
        }
    }
    if( nCode < 0 )
    {
        DXF_LAYER_READER_ERROR();
        delete poFeature;
        return NULL;
    }

    CPLDebug("Corner coordinates are", "%f,%f,%f,%f,%f,%f,%f,%f", dfX1, dfY1,
            dfX2, dfY2, dfX3, dfY3, dfX4, dfY4);

    OGRGeometryCollection* poCollection = NULL;
    poCollection = new OGRGeometryCollection();

    OGRLineString *poLS = new OGRLineString();
    poLS->addPoint(dfX1, dfY1);

    // corners in SOLID can be in any order, so we need to order them for
    // creating edges for polygon

    double dTo2 = Distance(dfX1, dfY1, dfX2, dfY2);
    double dTo3 = Distance(dfX1, dfY1, dfX3, dfY3);
    double dTo4 = Distance(dfX1, dfY1, dfX4, dfY4);

    OGRLineString *poLS4 = new OGRLineString();

    if (dTo2 <= dTo3 && dTo2 <= dTo4) {
        AddEdgesByNearest(poCollection, poLS, poLS4, dfX2, dfY2, dfX3, dfY3,
                dfX4, dfY4);
    } else if (dTo3 <= dTo2 && dTo3 <= dTo4) {
        AddEdgesByNearest(poCollection, poLS, poLS4, dfX3, dfY3, dfX2, dfY2,
                dfX4, dfY4);
    } else /* if (dTo4 <= dTo2 && dTo4 <= dTo3) */ {
        AddEdgesByNearest(poCollection, poLS, poLS4, dfX4, dfY4, dfX3, dfY3,
                dfX2, dfY2);
    }
    poLS4->addPoint(dfX1, dfY1);
    poCollection->addGeometryDirectly(poLS4);
    OGRErr eErr;

    OGRGeometry* poFinalGeom = (OGRGeometry *) OGRBuildPolygonFromEdges(
            (OGRGeometryH) poCollection, TRUE, TRUE, 0, &eErr);

    delete poCollection;

    ApplyOCSTransformer(poFinalGeom);

    poFeature->SetGeometryDirectly(poFinalGeom);

    if (nCode == 0)
        poDS->UnreadValue();

    // Set style pen color
    PrepareLineStyle(poFeature);

    return poFeature;
}

/************************************************************************/
/*                      GeometryInsertTransformer                       */
/************************************************************************/

class GeometryInsertTransformer : public OGRCoordinateTransformation
{
public:
    GeometryInsertTransformer() :
            dfXOffset(0),dfYOffset(0),dfZOffset(0),
            dfXScale(1.0),dfYScale(1.0),dfZScale(1.0),
            dfAngle(0.0) {}

    double dfXOffset;
    double dfYOffset;
    double dfZOffset;
    double dfXScale;
    double dfYScale;
    double dfZScale;
    double dfAngle;

    OGRSpatialReference *GetSourceCS() override { return NULL; }
    OGRSpatialReference *GetTargetCS() override { return NULL; }
    int Transform( int nCount,
                   double *x, double *y, double *z ) override
        { return TransformEx( nCount, x, y, z, NULL ); }

    int TransformEx( int nCount,
                     double *x, double *y, double *z = NULL,
                     int *pabSuccess = NULL ) override
        {
            for( int i = 0; i < nCount; i++ )
            {
                x[i] *= dfXScale;
                y[i] *= dfYScale;
                if( z )
                    z[i] *= dfZScale;

                const double dfXNew = x[i] * cos(dfAngle) - y[i] * sin(dfAngle);
                const double dfYNew = x[i] * sin(dfAngle) + y[i] * cos(dfAngle);

                x[i] = dfXNew;
                y[i] = dfYNew;

                x[i] += dfXOffset;
                y[i] += dfYOffset;
                if( z )
                    z[i] += dfZOffset;

                if( pabSuccess )
                    pabSuccess[i] = TRUE;
            }
            return TRUE;
        }
};

/************************************************************************/
/*                          TranslateINSERT()                           */
/************************************************************************/

OGRFeature *OGRDXFLayer::TranslateINSERT()

{
    char szLineBuf[257];
    int nCode = 0;
    OGRFeature *poFeature = new OGRFeature( poFeatureDefn );
    GeometryInsertTransformer oTransformer;
    CPLString osBlockName;
    double dfAngle = 0.0;

/* -------------------------------------------------------------------- */
/*      Process values.                                                 */
/* -------------------------------------------------------------------- */
    while( (nCode = poDS->ReadValue(szLineBuf,sizeof(szLineBuf))) > 0 )
    {
        switch( nCode )
        {
          case 10:
            oTransformer.dfXOffset = CPLAtof(szLineBuf);
            break;

          case 20:
            oTransformer.dfYOffset = CPLAtof(szLineBuf);
            break;

          case 30:
            oTransformer.dfZOffset = CPLAtof(szLineBuf);
            break;

          case 41:
            oTransformer.dfXScale = CPLAtof(szLineBuf);
            break;

          case 42:
            oTransformer.dfYScale = CPLAtof(szLineBuf);
            break;

          case 43:
            oTransformer.dfZScale = CPLAtof(szLineBuf);
            break;

          case 50:
            dfAngle = CPLAtof(szLineBuf);
            // We want to transform this to radians.
            // It is apparently always in degrees regardless of $AUNITS
            oTransformer.dfAngle = dfAngle * M_PI / 180.0;
            break;

          case 2:
            osBlockName = szLineBuf;
            break;

          default:
            TranslateGenericProperty( poFeature, nCode, szLineBuf );
            break;
        }
    }
    if( nCode < 0 )
    {
        DXF_LAYER_READER_ERROR();
        delete poFeature;
        return NULL;
    }

    if( nCode == 0 )
        poDS->UnreadValue();

/* -------------------------------------------------------------------- */
/*      In the case where we do not inlined blocks we just capture      */
/*      info on a point feature.                                        */
/* -------------------------------------------------------------------- */
    if( !poDS->InlineBlocks() )
    {
        // ApplyOCSTransformer( poGeom ); ?
        poFeature->SetGeometryDirectly(
            new OGRPoint( oTransformer.dfXOffset,
                          oTransformer.dfYOffset,
                          oTransformer.dfZOffset ) );

        poFeature->SetField( "BlockName", osBlockName );

        poFeature->SetField( "BlockAngle", dfAngle );
        poFeature->SetField( "BlockScale", 3, &(oTransformer.dfXScale) );

        return poFeature;
    }

/* -------------------------------------------------------------------- */
/*      Lookup the block.                                               */
/* -------------------------------------------------------------------- */
    DXFBlockDefinition *poBlock = poDS->LookupBlock( osBlockName );

    if( poBlock == NULL )
    {
        delete poFeature;
        return NULL;
    }

/* -------------------------------------------------------------------- */
/*      Transform the geometry.                                         */
/* -------------------------------------------------------------------- */
    if( poBlock->poGeometry != NULL )
    {
        OGRGeometry *poGeometry = poBlock->poGeometry->clone();

        poGeometry->transform( &oTransformer );

        poFeature->SetGeometryDirectly( poGeometry );
    }

/* -------------------------------------------------------------------- */
/*      If we have complete features associated with the block, push    */
/*      them on the pending feature stack copying over key override     */
/*      information.                                                    */
/*                                                                      */
/*      Note that while we transform the geometry of the features we    */
/*      don't adjust subtle things like text angle.                     */
/* -------------------------------------------------------------------- */
    for( unsigned int iSubFeat = 0;
         iSubFeat < poBlock->apoFeatures.size();
         iSubFeat++ )
    {
        OGRFeature *poSubFeature = poBlock->apoFeatures[iSubFeat]->Clone();
        CPLString osCompEntityId;

        if( poSubFeature->GetGeometryRef() != NULL )
            poSubFeature->GetGeometryRef()->transform( &oTransformer );

        ACAdjustText( dfAngle, oTransformer.dfXScale, poSubFeature );

#ifdef notdef
        osCompEntityId = poSubFeature->GetFieldAsString( "EntityHandle" );
        osCompEntityId += ":";
#endif
        osCompEntityId += poFeature->GetFieldAsString( "EntityHandle" );

        poSubFeature->SetField( "EntityHandle", osCompEntityId );

        apoPendingFeatures.push( poSubFeature );
    }

/* -------------------------------------------------------------------- */
/*      Return the working feature if we had geometry, otherwise        */
/*      return NULL and let the machinery find the rest of the          */
/*      features in the pending feature stack.                          */
/* -------------------------------------------------------------------- */
    if( poBlock->poGeometry == NULL )
    {
        delete poFeature;
        return NULL;
    }
    else
    {
        // Set style pen color
        PrepareLineStyle( poFeature );
        return poFeature;
    }
}

/************************************************************************/
/*                      GetNextUnfilteredFeature()                      */
/************************************************************************/

OGRFeature *OGRDXFLayer::GetNextUnfilteredFeature()

{
    OGRFeature *poFeature = NULL;

/* -------------------------------------------------------------------- */
/*      If we have pending features, return one of them.                */
/* -------------------------------------------------------------------- */
    if( !apoPendingFeatures.empty() )
    {
        poFeature = apoPendingFeatures.front();
        apoPendingFeatures.pop();

        poFeature->SetFID( iNextFID++ );
        return poFeature;
    }

/* -------------------------------------------------------------------- */
/*      Read the entity type.                                           */
/* -------------------------------------------------------------------- */
    char szLineBuf[257];

    while( poFeature == NULL )
    {
        // read ahead to an entity.
        int nCode = 0;
        while( (nCode = poDS->ReadValue(szLineBuf,sizeof(szLineBuf))) > 0 ) {}
        if( nCode < 0 )
        {
            DXF_LAYER_READER_ERROR();
            return NULL;
        }

        if( EQUAL(szLineBuf,"ENDSEC") )
        {
            //CPLDebug( "DXF", "Clean end of features at ENDSEC." );
            poDS->UnreadValue();
            return NULL;
        }

        if( EQUAL(szLineBuf,"ENDBLK") )
        {
            //CPLDebug( "DXF", "Clean end of block at ENDBLK." );
            poDS->UnreadValue();
            return NULL;
        }

/* -------------------------------------------------------------------- */
/*      Handle the entity.                                              */
/* -------------------------------------------------------------------- */
        oStyleProperties.clear();

        if( EQUAL(szLineBuf,"POINT") )
        {
            poFeature = TranslatePOINT();
        }
        else if( EQUAL(szLineBuf,"MTEXT") )
        {
            poFeature = TranslateMTEXT();
        }
        else if( EQUAL(szLineBuf,"TEXT")
                 || EQUAL(szLineBuf,"ATTDEF") )
        {
            poFeature = TranslateTEXT();
        }
        else if( EQUAL(szLineBuf,"LINE") )
        {
            poFeature = TranslateLINE();
        }
        else if( EQUAL(szLineBuf,"POLYLINE") )
        {
            poFeature = TranslatePOLYLINE();
        }
        else if( EQUAL(szLineBuf,"LWPOLYLINE") )
        {
            poFeature = TranslateLWPOLYLINE();
        }
        else if( EQUAL(szLineBuf,"CIRCLE") )
        {
            poFeature = TranslateCIRCLE();
        }
        else if( EQUAL(szLineBuf,"ELLIPSE") )
        {
            poFeature = TranslateELLIPSE();
        }
        else if( EQUAL(szLineBuf,"ARC") )
        {
            poFeature = TranslateARC();
        }
        else if( EQUAL(szLineBuf,"SPLINE") )
        {
            poFeature = TranslateSPLINE();
        }
        else if( EQUAL(szLineBuf,"3DFACE") )
        {
            poFeature = Translate3DFACE();
        }
        else if( EQUAL(szLineBuf,"INSERT") )
        {
            poFeature = TranslateINSERT();
        }
        else if( EQUAL(szLineBuf,"DIMENSION") )
        {
            poFeature = TranslateDIMENSION();
        }
        else if( EQUAL(szLineBuf,"HATCH") )
        {
            poFeature = TranslateHATCH();
        }
        else if( EQUAL(szLineBuf,"SOLID") )
        {
            poFeature = TranslateSOLID();
        }
        else
        {
            if( oIgnoredEntities.count(szLineBuf) == 0 )
            {
                oIgnoredEntities.insert( szLineBuf );
                CPLDebug( "DWG", "Ignoring one or more of entity '%s'.",
                          szLineBuf );
            }
        }
    }

/* -------------------------------------------------------------------- */
/*      Set FID.                                                        */
/* -------------------------------------------------------------------- */
    poFeature->SetFID( iNextFID++ );
    m_nFeaturesRead++;

    return poFeature;
}

/************************************************************************/
/*                           GetNextFeature()                           */
/************************************************************************/

OGRFeature *OGRDXFLayer::GetNextFeature()

{
    while( true )
    {
        OGRFeature *poFeature = GetNextUnfilteredFeature();

        if( poFeature == NULL )
            return NULL;

        if( (m_poFilterGeom == NULL
             || FilterGeometry( poFeature->GetGeometryRef() ) )
            && (m_poAttrQuery == NULL
                || m_poAttrQuery->Evaluate( poFeature ) ) )
        {
            return poFeature;
        }

        delete poFeature;
    }
}

/************************************************************************/
/*                           TestCapability()                           */
/************************************************************************/

int OGRDXFLayer::TestCapability( const char * pszCap )

{
    return EQUAL(pszCap, OLCStringsAsUTF8);
}
