/******************************************************************************
 * $Id: ogrshapelayer.cpp 34069 2016-04-23 17:59:00Z rouault $
 *
 * Project:  OpenGIS Simple Features Reference Implementation
 * Purpose:  Implements OGRShapeLayer class.
 * Author:   Frank Warmerdam, warmerdam@pobox.com
 *
 ******************************************************************************
 * Copyright (c) 1999,  Les Technologies SoftMap Inc.
 * Copyright (c) 2007-2013, 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 "ogrshape.h"
#include "cpl_conv.h"
#include "cpl_string.h"
#include "ogr_p.h"
#include "cpl_time.h"

#define FD_OPENED           0
#define FD_CLOSED           1
#define FD_CANNOT_REOPEN    2

#define UNSUPPORTED_OP_READ_ONLY "%s : unsupported operation on a read-only datasource."

CPL_CVSID("$Id: ogrshapelayer.cpp 34069 2016-04-23 17:59:00Z rouault $");

/************************************************************************/
/*                           OGRShapeLayer()                            */
/************************************************************************/

OGRShapeLayer::OGRShapeLayer( OGRShapeDataSource* poDSIn,
                              const char * pszFullNameIn,
                              SHPHandle hSHPIn, DBFHandle hDBFIn,
                              OGRSpatialReference *poSRSIn, int bSRSSetIn,
                              int bUpdate,
                              OGRwkbGeometryType eReqType,
                              char ** papszCreateOptions ) :
    OGRAbstractProxiedLayer(poDSIn->GetPool()),
    poDS(poDSIn),
    iNextShapeId(0),
    hSHP(hSHPIn),
    hDBF(hDBFIn),
    bUpdateAccess(bUpdate),
    eRequestedGeomType(eReqType),
    panMatchingFIDs(NULL),
    iMatchingFID(0),
    m_poFilterGeomLastValid(NULL),
    nSpatialFIDCount(0),
    panSpatialFIDs(NULL),
    bHeaderDirty(FALSE),
    bSHPNeedsRepack(FALSE),
    bCheckedForQIX(FALSE),
    hQIX(NULL),
    bCheckedForSBN(FALSE),
    hSBN(NULL),
    bSbnSbxDeleted(FALSE),
    bTruncationWarningEmitted(FALSE),
    eFileDescriptorsState(FD_OPENED),
    bResizeAtClose(FALSE),
    bCreateSpatialIndexAtClose(FALSE)
{
    pszFullName = CPLStrdup(pszFullNameIn);

    if( hSHP != NULL )
    {
        nTotalShapeCount = hSHP->nRecords;
        if( hDBF != NULL && hDBF->nRecords != nTotalShapeCount )
        {
            CPLDebug("Shape", "Inconsistent record number in .shp (%d) and in .dbf (%d)",
                     hSHP->nRecords, hDBF->nRecords);
        }
    }
    else
        nTotalShapeCount = hDBF->nRecords;

    bHSHPWasNonNULL = hSHPIn != NULL;
    bHDBFWasNonNULL = hDBFIn != NULL;
    if (!TouchLayer())
    {
        CPLDebug("Shape", "TouchLayer in shape ctor failed. ");
    }

    if( hDBF != NULL && hDBF->pszCodePage != NULL )
    {
        CPLDebug( "Shape", "DBF Codepage = %s for %s",
                  hDBF->pszCodePage, pszFullName );

        // Not too sure about this, but it seems like better than nothing.
        osEncoding = ConvertCodePage( hDBF->pszCodePage );
    }

    if( hDBF != NULL )
    {
        if( !(hDBF->nUpdateYearSince1900 == 95 &&
              hDBF->nUpdateMonth == 7 &&
              hDBF->nUpdateDay == 26) )
        {
            SetMetadataItem( "DBF_DATE_LAST_UPDATE", CPLSPrintf("%04d-%02d-%02d",
                            hDBF->nUpdateYearSince1900 + 1900,
                            hDBF->nUpdateMonth, hDBF->nUpdateDay) );
        }
        struct tm tm;
        CPLUnixTimeToYMDHMS(time(NULL), &tm);
        DBFSetLastModifiedDate( hDBF, tm.tm_year,
                                tm.tm_mon + 1, tm.tm_mday );
    }

    const char* pszShapeEncoding = NULL;
    pszShapeEncoding = CSLFetchNameValue(poDS->GetOpenOptions(), "ENCODING");
    if( pszShapeEncoding == NULL && osEncoding == "")
        pszShapeEncoding = CSLFetchNameValue( papszCreateOptions, "ENCODING" );
    if( pszShapeEncoding == NULL )
        pszShapeEncoding = CPLGetConfigOption( "SHAPE_ENCODING", NULL );
    if( pszShapeEncoding != NULL )
        osEncoding = pszShapeEncoding;

    if( osEncoding != "" )
    {
        CPLDebug( "Shape", "Treating as encoding '%s'.", osEncoding.c_str() );

        if (!TestCapability(OLCStringsAsUTF8))
        {
            CPLDebug( "Shape", "Cannot recode from '%s'. Disabling recoding", osEncoding.c_str() );
            osEncoding = "";
        }
    }

    poFeatureDefn = SHPReadOGRFeatureDefn( CPLGetBasename(pszFullName),
                                           hSHP, hDBF, osEncoding,
               CSLFetchBoolean(poDS->GetOpenOptions(), "ADJUST_TYPE", FALSE) );

    /* To make sure that GetLayerDefn()->GetGeomFieldDefn(0)->GetSpatialRef() == GetSpatialRef() */
    OGRwkbGeometryType eGeomType = poFeatureDefn->GetGeomType();
    if( eGeomType != wkbNone )
    {
        OGRwkbGeometryType eType;

        if( eRequestedGeomType == wkbNone )
        {
            eType = eGeomType;

            const char* pszAdjustGeomType = CSLFetchNameValueDef(
                            poDS->GetOpenOptions(), "ADJUST_GEOM_TYPE", "FIRST_SHAPE");
            const bool bFirstShape = EQUAL(pszAdjustGeomType, "FIRST_SHAPE");
            const bool bAllShapes  = EQUAL(pszAdjustGeomType, "ALL_SHAPES");
            if( (hSHP != NULL) && (hSHP->nRecords > 0) && wkbHasM(eType) &&
                (bFirstShape || bAllShapes) )
            {
                bool bMIsUsed = false;
                for(int iShape=0; iShape < hSHP->nRecords; iShape++)
                {
                    SHPObject   *psShape = SHPReadObject( hSHP, iShape );
                    if( psShape )
                    {
                        if( psShape->bMeasureIsUsed &&
                            psShape->nVertices > 0 &&
                            psShape->padfM != NULL )
                        {
                            for(int i=0;i<psShape->nVertices;i++)
                            {
                                /* Per the spec, if the M value is smaller than -1e38,
                                 * it is a nodata value
                                 */
                                if( psShape->padfM[i] > -1e38 )
                                {
                                    bMIsUsed = true;
                                    break;
                                }
                            }
                        }

                        SHPDestroyObject(psShape);
                    }
                    if( bFirstShape || bMIsUsed )
                        break;
                }
                if( !bMIsUsed )
                    eType = OGR_GT_SetModifier(eType, wkbHasZ(eType), FALSE);
            }
        }
        else
            eType = eRequestedGeomType;

        OGRShapeGeomFieldDefn* poGeomFieldDefn =
            //new OGRShapeGeomFieldDefn(pszFullName, eGeomType, bSRSSetIn, poSRSIn);
            new OGRShapeGeomFieldDefn(pszFullName, eType, bSRSSetIn, poSRSIn);
        poFeatureDefn->SetGeomType(wkbNone);
        poFeatureDefn->AddGeomFieldDefn(poGeomFieldDefn, FALSE);
    }
    else if( bSRSSetIn && poSRSIn != NULL )
        poSRSIn->Release();
    SetDescription( poFeatureDefn->GetName() );
    bRewindOnWrite = CPLTestBool(CPLGetConfigOption( "SHAPE_REWIND_ON_WRITE", "YES" ));
}

/************************************************************************/
/*                           ~OGRShapeLayer()                           */
/************************************************************************/

OGRShapeLayer::~OGRShapeLayer()

{
    if( bResizeAtClose && hDBF != NULL )
    {
        ResizeDBF();
    }
    if( bCreateSpatialIndexAtClose && hSHP != NULL )
    {
        CreateSpatialIndex(0);
    }

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

    ClearMatchingFIDs();
    ClearSpatialFIDs();

    CPLFree( pszFullName );

    if( poFeatureDefn != NULL )
        poFeatureDefn->Release();

    if( hDBF != NULL )
        DBFClose( hDBF );

    if( hSHP != NULL )
        SHPClose( hSHP );

    if( hQIX != NULL )
        SHPCloseDiskTree( hQIX );

    if( hSBN != NULL )
        SBNCloseDiskTree( hSBN );
}


/************************************************************************/
/*                       SetModificationDate()                          */
/************************************************************************/

void OGRShapeLayer::SetModificationDate(const char* pszStr)
{
    if( hDBF && pszStr )
    {
        int year, month, day;
        if ((sscanf(pszStr, "%04d-%02d-%02d", &year, &month, &day) == 3 ||
             sscanf(pszStr, "%04d/%02d/%02d", &year, &month, &day) == 3) &&
            (year >= 1900 && year <= 1900 + 255 && month >= 1 && month <= 12 &&
             day >= 1 && day <= 31))
        {
            DBFSetLastModifiedDate( hDBF, year - 1900, month, day );
        }
    }
}

/************************************************************************/
/*                          ConvertCodePage()                           */
/************************************************************************/

CPLString OGRShapeLayer::ConvertCodePage( const char *pszCodePage )

{
    CPLString l_osEncoding;

    if( pszCodePage == NULL )
        return l_osEncoding;

    if( STARTS_WITH_CI(pszCodePage, "LDID/") )
    {
        int nCP = -1; // windows code page.

        //http://www.autopark.ru/ASBProgrammerGuide/DBFSTRUC.HTM
        switch( atoi(pszCodePage+5) )
        {
          case 1: nCP = 437;      break;
          case 2: nCP = 850;      break;
          case 3: nCP = 1252;     break;
          case 4: nCP = 10000;    break;
          case 8: nCP = 865;      break;
          case 10: nCP = 850;     break;
          case 11: nCP = 437;     break;
          case 13: nCP = 437;     break;
          case 14: nCP = 850;     break;
          case 15: nCP = 437;     break;
          case 16: nCP = 850;     break;
          case 17: nCP = 437;     break;
          case 18: nCP = 850;     break;
          case 19: nCP = 932;     break;
          case 20: nCP = 850;     break;
          case 21: nCP = 437;     break;
          case 22: nCP = 850;     break;
          case 23: nCP = 865;     break;
          case 24: nCP = 437;     break;
          case 25: nCP = 437;     break;
          case 26: nCP = 850;     break;
          case 27: nCP = 437;     break;
          case 28: nCP = 863;     break;
          case 29: nCP = 850;     break;
          case 31: nCP = 852;     break;
          case 34: nCP = 852;     break;
          case 35: nCP = 852;     break;
          case 36: nCP = 860;     break;
          case 37: nCP = 850;     break;
          case 38: nCP = 866;     break;
          case 55: nCP = 850;     break;
          case 64: nCP = 852;     break;
          case 77: nCP = 936;     break;
          case 78: nCP = 949;     break;
          case 79: nCP = 950;     break;
          case 80: nCP = 874;     break;
          case 87: return CPL_ENC_ISO8859_1;
          case 88: nCP = 1252;     break;
          case 89: nCP = 1252;     break;
          case 100: nCP = 852;     break;
          case 101: nCP = 866;     break;
          case 102: nCP = 865;     break;
          case 103: nCP = 861;     break;
          case 104: nCP = 895;     break;
          case 105: nCP = 620;     break;
          case 106: nCP = 737;     break;
          case 107: nCP = 857;     break;
          case 108: nCP = 863;     break;
          case 120: nCP = 950;     break;
          case 121: nCP = 949;     break;
          case 122: nCP = 936;     break;
          case 123: nCP = 932;     break;
          case 124: nCP = 874;     break;
          case 134: nCP = 737;     break;
          case 135: nCP = 852;     break;
          case 136: nCP = 857;     break;
          case 150: nCP = 10007;   break;
          case 151: nCP = 10029;   break;
          case 200: nCP = 1250;    break;
          case 201: nCP = 1251;    break;
          case 202: nCP = 1254;    break;
          case 203: nCP = 1253;    break;
          case 204: nCP = 1257;    break;
          default: break;
        }

        if( nCP != -1 )
        {
            l_osEncoding.Printf( "CP%d", nCP );
            return l_osEncoding;
        }
    }

    // From the CPG file
    // http://resources.arcgis.com/fr/content/kbase?fa=articleShow&d=21106

    if( (atoi(pszCodePage) >= 437 && atoi(pszCodePage) <= 950)
        || (atoi(pszCodePage) >= 1250 && atoi(pszCodePage) <= 1258) )
    {
        l_osEncoding.Printf( "CP%d", atoi(pszCodePage) );
        return l_osEncoding;
    }
    if( STARTS_WITH_CI(pszCodePage, "8859") )
    {
        if( pszCodePage[4] == '-' )
            l_osEncoding.Printf( "ISO-8859-%s", pszCodePage + 5 );
        else
            l_osEncoding.Printf( "ISO-8859-%s", pszCodePage + 4 );
        return l_osEncoding;
    }
    if( STARTS_WITH_CI(pszCodePage, "UTF-8") )
        return CPL_ENC_UTF8;

    // try just using the CPG value directly.  Works for stuff like Big5.
    return pszCodePage;
}

/************************************************************************/
/*                            CheckForQIX()                             */
/************************************************************************/

int OGRShapeLayer::CheckForQIX()

{
    const char *pszQIXFilename;

    if( bCheckedForQIX )
        return hQIX != NULL;

    pszQIXFilename = CPLResetExtension( pszFullName, "qix" );

    hQIX = SHPOpenDiskTree( pszQIXFilename, NULL );

    bCheckedForQIX = TRUE;

    return hQIX != NULL;
}

/************************************************************************/
/*                            CheckForSBN()                             */
/************************************************************************/

int OGRShapeLayer::CheckForSBN()

{
    const char *pszSBNFilename;

    if( bCheckedForSBN )
        return hSBN != NULL;

    pszSBNFilename = CPLResetExtension( pszFullName, "sbn" );

    hSBN = SBNOpenDiskTree( pszSBNFilename, NULL );

    bCheckedForSBN = TRUE;

    return hSBN != NULL;
}

/************************************************************************/
/*                            ScanIndices()                             */
/*                                                                      */
/*      Utilize optional spatial and attribute indices if they are      */
/*      available.                                                      */
/************************************************************************/

int OGRShapeLayer::ScanIndices()

{
    iMatchingFID = 0;

/* -------------------------------------------------------------------- */
/*      Utilize attribute index if appropriate.                         */
/* -------------------------------------------------------------------- */
    if( m_poAttrQuery != NULL )
    {
        CPLAssert( panMatchingFIDs == NULL );

        InitializeIndexSupport( pszFullName );

        panMatchingFIDs = m_poAttrQuery->EvaluateAgainstIndices( this,
                                                                 NULL );
    }

/* -------------------------------------------------------------------- */
/*      Check for spatial index if we have a spatial query.             */
/* -------------------------------------------------------------------- */

    if( m_poFilterGeom == NULL || hSHP == NULL )
        return TRUE;

    OGREnvelope oSpatialFilterEnvelope;
    int bTryQIXorSBN = TRUE;

    m_poFilterGeom->getEnvelope( &oSpatialFilterEnvelope );

    OGREnvelope oLayerExtent;
    if (GetExtent(&oLayerExtent, TRUE) == OGRERR_NONE)
    {
        if (oSpatialFilterEnvelope.Contains(oLayerExtent))
        {
            // The spatial filter is larger than the layer extent. No use of .qix file for now
            return TRUE;
        }
        else if (!oSpatialFilterEnvelope.Intersects(oLayerExtent))
        {
            /* No intersection : no need to check for .qix or .sbn */
            bTryQIXorSBN = FALSE;

            /* Set an empty result for spatial FIDs */
            free(panSpatialFIDs);
            panSpatialFIDs = (int*) calloc(1, sizeof(int));
            nSpatialFIDCount = 0;

            delete m_poFilterGeomLastValid;
            m_poFilterGeomLastValid = m_poFilterGeom->clone();
        }
    }

    if( bTryQIXorSBN )
    {
        if( !bCheckedForQIX )
            CPL_IGNORE_RET_VAL(CheckForQIX());
        if( hQIX == NULL && !bCheckedForSBN )
            CPL_IGNORE_RET_VAL(CheckForSBN());
    }

/* -------------------------------------------------------------------- */
/*      Compute spatial index if appropriate.                           */
/* -------------------------------------------------------------------- */
    if( bTryQIXorSBN && (hQIX != NULL || hSBN != NULL) && panSpatialFIDs == NULL )
    {
        double adfBoundsMin[4], adfBoundsMax[4];

        adfBoundsMin[0] = oSpatialFilterEnvelope.MinX;
        adfBoundsMin[1] = oSpatialFilterEnvelope.MinY;
        adfBoundsMin[2] = 0.0;
        adfBoundsMin[3] = 0.0;
        adfBoundsMax[0] = oSpatialFilterEnvelope.MaxX;
        adfBoundsMax[1] = oSpatialFilterEnvelope.MaxY;
        adfBoundsMax[2] = 0.0;
        adfBoundsMax[3] = 0.0;

        if( hQIX != NULL )
            panSpatialFIDs = SHPSearchDiskTreeEx( hQIX,
                                                  adfBoundsMin, adfBoundsMax,
                                                  &nSpatialFIDCount );
        else
            panSpatialFIDs = SBNSearchDiskTree( hSBN,
                                                adfBoundsMin, adfBoundsMax,
                                                &nSpatialFIDCount );

        CPLDebug( "SHAPE", "Used spatial index, got %d matches.",
                  nSpatialFIDCount );

        delete m_poFilterGeomLastValid;
        m_poFilterGeomLastValid = m_poFilterGeom->clone();
    }

/* -------------------------------------------------------------------- */
/*      Use spatial index if appropriate.                               */
/* -------------------------------------------------------------------- */
    if( panSpatialFIDs != NULL )
    {
        // Use resulting list as matching FID list (but reallocate and
        // terminate with OGRNullFID).

        if( panMatchingFIDs == NULL )
        {
            int i;

            panMatchingFIDs = (GIntBig *)
                CPLMalloc(sizeof(GIntBig) * (nSpatialFIDCount+1) );
            for( i = 0; i < nSpatialFIDCount; i++ )
                panMatchingFIDs[i] = (GIntBig) panSpatialFIDs[i];
            panMatchingFIDs[nSpatialFIDCount] = OGRNullFID;
        }

        // Cull attribute index matches based on those in the spatial index
        // result set.  We assume that the attribute results are in sorted
        // order.
        else
        {
            int iRead, iWrite=0, iSpatial=0;

            for( iRead = 0; panMatchingFIDs[iRead] != OGRNullFID; iRead++ )
            {
                while( iSpatial < nSpatialFIDCount
                       && panSpatialFIDs[iSpatial] < panMatchingFIDs[iRead] )
                    iSpatial++;

                if( iSpatial == nSpatialFIDCount )
                    continue;

                if( panSpatialFIDs[iSpatial] == panMatchingFIDs[iRead] )
                    panMatchingFIDs[iWrite++] = panMatchingFIDs[iRead];
            }
            panMatchingFIDs[iWrite] = OGRNullFID;
        }

        if (nSpatialFIDCount > 100000)
        {
            ClearSpatialFIDs();
        }
    }

    return TRUE;
}

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

void OGRShapeLayer::ResetReading()

{
    if (!TouchLayer())
        return;

    iMatchingFID = 0;

    iNextShapeId = 0;

    if( bHeaderDirty && bUpdateAccess )
        SyncToDisk();
}

/************************************************************************/
/*                        ClearMatchingFIDs()                           */
/************************************************************************/

void OGRShapeLayer::ClearMatchingFIDs()
{
/* -------------------------------------------------------------------- */
/*      Clear previous index search result, if any.                     */
/* -------------------------------------------------------------------- */
    CPLFree( panMatchingFIDs );
    panMatchingFIDs = NULL;
}

/************************************************************************/
/*                        ClearSpatialFIDs()                           */
/************************************************************************/

void OGRShapeLayer::ClearSpatialFIDs()
{
    if ( panSpatialFIDs != NULL )
    {
        CPLDebug("SHAPE", "Clear panSpatialFIDs");
        free( panSpatialFIDs );
    }
    panSpatialFIDs = NULL;
    nSpatialFIDCount = 0;

    delete m_poFilterGeomLastValid;
    m_poFilterGeomLastValid = NULL;
}

/************************************************************************/
/*                         SetSpatialFilter()                           */
/************************************************************************/

void OGRShapeLayer::SetSpatialFilter( OGRGeometry * poGeomIn )
{
    ClearMatchingFIDs();

    if( poGeomIn == NULL )
    {
        /* Do nothing */
    }
    else if ( m_poFilterGeomLastValid != NULL &&
              m_poFilterGeomLastValid->Equals(poGeomIn) )
    {
        /* Do nothing */
    }
    else if ( panSpatialFIDs != NULL )
    {
        /* We clear the spatialFIDs only if we have a new non-NULL */
        /* spatial filter, otherwise we keep the previous result */
        /* cached. This can be useful when several SQL layers */
        /* rely on the same table layer, and use the same spatial */
        /* filters. But as there is in the destructor of OGRGenSQLResultsLayer */
        /* a clearing of the spatial filter of the table layer, we */
        /* need this trick. */
        ClearSpatialFIDs();
    }

    return OGRLayer::SetSpatialFilter(poGeomIn);
}

/************************************************************************/
/*                         SetAttributeFilter()                         */
/************************************************************************/

OGRErr OGRShapeLayer::SetAttributeFilter( const char * pszAttributeFilter )
{
    ClearMatchingFIDs();

    return OGRLayer::SetAttributeFilter(pszAttributeFilter);
}

/************************************************************************/
/*                           SetNextByIndex()                           */
/*                                                                      */
/*      If we already have an FID list, we can easily reposition        */
/*      ourselves in it.                                                */
/************************************************************************/

OGRErr OGRShapeLayer::SetNextByIndex( GIntBig nIndex )

{
    if (!TouchLayer())
        return OGRERR_FAILURE;

    if( nIndex < 0 || nIndex > INT_MAX )
        return OGRERR_FAILURE;

    // Eventually we should try to use panMatchingFIDs list
    // if available and appropriate.
    if( m_poFilterGeom != NULL || m_poAttrQuery != NULL )
        return OGRLayer::SetNextByIndex( nIndex );

    iNextShapeId = (int)nIndex;

    return OGRERR_NONE;
}

/************************************************************************/
/*                             FetchShape()                             */
/*                                                                      */
/*      Take a shape id, a geometry, and a feature, and set the feature */
/*      if the shapeid bbox intersects the geometry.                    */
/************************************************************************/

OGRFeature *OGRShapeLayer::FetchShape(int iShapeId /*, OGREnvelope* psShapeExtent */)

{
    OGRFeature *poFeature;

    if (m_poFilterGeom != NULL && hSHP != NULL )
    {
        SHPObject   *psShape;

        psShape = SHPReadObject( hSHP, iShapeId );

        // do not trust degenerate bounds on non-point geometries
        // or bounds on null shapes.
        if( psShape == NULL
            || (psShape->nSHPType != SHPT_POINT
                && psShape->nSHPType != SHPT_POINTZ
                && psShape->nSHPType != SHPT_POINTM
                && (psShape->dfXMin == psShape->dfXMax
                 || psShape->dfYMin == psShape->dfYMax))
            || psShape->nSHPType == SHPT_NULL )
        {
            poFeature = SHPReadOGRFeature( hSHP, hDBF, poFeatureDefn,
                                           iShapeId, psShape, osEncoding );
        }
        else if( m_sFilterEnvelope.MaxX < psShape->dfXMin
                 || m_sFilterEnvelope.MaxY < psShape->dfYMin
                 || psShape->dfXMax  < m_sFilterEnvelope.MinX
                 || psShape->dfYMax < m_sFilterEnvelope.MinY )
        {
            SHPDestroyObject(psShape);
            poFeature = NULL;
        }
        else
        {
            /*psShapeExtent->MinX = psShape->dfXMin;
            psShapeExtent->MinY = psShape->dfYMin;
            psShapeExtent->MaxX = psShape->dfXMax;
            psShapeExtent->MaxY = psShape->dfYMax;*/
            poFeature = SHPReadOGRFeature( hSHP, hDBF, poFeatureDefn,
                                           iShapeId, psShape, osEncoding );
        }
    }
    else
    {
        poFeature = SHPReadOGRFeature( hSHP, hDBF, poFeatureDefn,
                                       iShapeId, NULL, osEncoding );
    }

    return poFeature;
}

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

OGRFeature *OGRShapeLayer::GetNextFeature()

{
    if (!TouchLayer())
        return NULL;

    OGRFeature  *poFeature = NULL;

/* -------------------------------------------------------------------- */
/*      Collect a matching list if we have attribute or spatial         */
/*      indices.  Only do this on the first request for a given pass    */
/*      of course.                                                      */
/* -------------------------------------------------------------------- */
    if( (m_poAttrQuery != NULL || m_poFilterGeom != NULL)
        && iNextShapeId == 0 && panMatchingFIDs == NULL )
    {
        ScanIndices();
    }

/* -------------------------------------------------------------------- */
/*      Loop till we find a feature matching our criteria.              */
/* -------------------------------------------------------------------- */
    while( true )
    {
        //OGREnvelope oShapeExtent;

        if( panMatchingFIDs != NULL )
        {
            if( panMatchingFIDs[iMatchingFID] == OGRNullFID )
            {
                return NULL;
            }

            // Check the shape object's geometry, and if it matches
            // any spatial filter, return it.
            poFeature = FetchShape((int)panMatchingFIDs[iMatchingFID] /*, &oShapeExtent*/);

            iMatchingFID++;

        }
        else
        {
            if( iNextShapeId >= nTotalShapeCount )
            {
                return NULL;
            }

            if( hDBF )
            {
                if (DBFIsRecordDeleted( hDBF, iNextShapeId ))
                    poFeature = NULL;
                else if( VSIFEofL(VSI_SHP_GetVSIL(hDBF->fp)) )
                    return NULL; /* There's an I/O error */
                else
                    poFeature = FetchShape(iNextShapeId /*, &oShapeExtent */);
            }
            else
                poFeature = FetchShape(iNextShapeId /*, &oShapeExtent */);

            iNextShapeId++;
        }

        if( poFeature != NULL )
        {
            OGRGeometry* poGeom = poFeature->GetGeometryRef();
            if( poGeom != NULL )
            {
                poGeom->assignSpatialReference( GetSpatialRef() );
            }

            m_nFeaturesRead++;

            if( (m_poFilterGeom == NULL || FilterGeometry( poGeom /*, &oShapeExtent*/ ) )
                && (m_poAttrQuery == NULL || m_poAttrQuery->Evaluate( poFeature )) )
            {
                return poFeature;
            }

            delete poFeature;
        }
    }
}

/************************************************************************/
/*                             GetFeature()                             */
/************************************************************************/

OGRFeature *OGRShapeLayer::GetFeature( GIntBig nFeatureId )

{
    if (!TouchLayer() || nFeatureId > INT_MAX )
        return NULL;

    OGRFeature *poFeature = NULL;
    poFeature = SHPReadOGRFeature( hSHP, hDBF, poFeatureDefn, (int)nFeatureId, NULL,
                                   osEncoding );

    if( poFeature != NULL )
    {
        if( poFeature->GetGeometryRef() != NULL )
        {
            poFeature->GetGeometryRef()->assignSpatialReference( GetSpatialRef() );
        }

        m_nFeaturesRead++;

        return poFeature;
    }

    /*
     * Reading shape feature failed.
     */
    return NULL;
}

/************************************************************************/
/*                             ISetFeature()                             */
/************************************************************************/

OGRErr OGRShapeLayer::ISetFeature( OGRFeature *poFeature )

{
    if (!TouchLayer())
        return OGRERR_FAILURE;

    if( !bUpdateAccess )
    {
        CPLError( CE_Failure, CPLE_NotSupported,
                  UNSUPPORTED_OP_READ_ONLY,
                  "SetFeature");
        return OGRERR_FAILURE;
    }

    GIntBig nFID = poFeature->GetFID();
    if( nFID < 0
        || (hSHP != NULL && nFID >= hSHP->nRecords)
        || (hDBF != NULL && nFID >= hDBF->nRecords) )
    {
        return OGRERR_NON_EXISTING_FEATURE;
    }

    bHeaderDirty = TRUE;
    if( CheckForQIX() || CheckForSBN() )
        DropSpatialIndex();

    unsigned int nOffset = 0;
    unsigned int nSize = 0;
    if( hSHP != NULL )
    {
        nOffset = hSHP->panRecOffset[nFID];
        nSize = hSHP->panRecSize[nFID];
    }

    OGRErr eErr = SHPWriteOGRFeature( hSHP, hDBF, poFeatureDefn, poFeature,
                                      osEncoding, &bTruncationWarningEmitted,
                                      bRewindOnWrite );

    if( hSHP != NULL )
    {
        if( nOffset != hSHP->panRecOffset[nFID] ||
            nSize != hSHP->panRecSize[nFID] )
        {
            bSHPNeedsRepack = TRUE;
        }
    }

    return eErr;
}

/************************************************************************/
/*                           DeleteFeature()                            */
/************************************************************************/

OGRErr OGRShapeLayer::DeleteFeature( GIntBig nFID )

{
    if (!TouchLayer() || nFID > INT_MAX )
        return OGRERR_FAILURE;

    if( !bUpdateAccess )
    {
        CPLError( CE_Failure, CPLE_NotSupported,
                  UNSUPPORTED_OP_READ_ONLY,
                  "DeleteFeature");
        return OGRERR_FAILURE;
    }

    if( nFID < 0
        || (hSHP != NULL && nFID >= hSHP->nRecords)
        || (hDBF != NULL && nFID >= hDBF->nRecords) )
    {
        return OGRERR_NON_EXISTING_FEATURE;
    }

    if( !hDBF )
    {
        CPLError( CE_Failure, CPLE_AppDefined,
                  "Attempt to delete shape in shapefile with no .dbf file.\n"
                  "Deletion is done by marking record deleted in dbf\n"
                  "and is not supported without a .dbf file." );
        return OGRERR_FAILURE;
    }

    if( DBFIsRecordDeleted( hDBF, (int)nFID ) )
    {
        return OGRERR_NON_EXISTING_FEATURE;
    }

    if( !DBFMarkRecordDeleted( hDBF, (int)nFID, TRUE ) )
        return OGRERR_FAILURE;

    bHeaderDirty = TRUE;
    if( CheckForQIX() || CheckForSBN() )
        DropSpatialIndex();

    return OGRERR_NONE;
}

/************************************************************************/
/*                           ICreateFeature()                            */
/************************************************************************/

OGRErr OGRShapeLayer::ICreateFeature( OGRFeature *poFeature )

{
    OGRErr eErr;

    if (!TouchLayer())
        return OGRERR_FAILURE;

    if( !bUpdateAccess )
    {
        CPLError( CE_Failure, CPLE_NotSupported,
                  UNSUPPORTED_OP_READ_ONLY,
                  "CreateFeature");
        return OGRERR_FAILURE;
    }

    if( hDBF != NULL &&
        !VSI_SHP_WriteMoreDataOK(hDBF->fp, hDBF->nRecordLength) )
    {
        return OGRERR_FAILURE;
    }

    bHeaderDirty = TRUE;
    if( CheckForQIX() || CheckForSBN() )
        DropSpatialIndex();

    poFeature->SetFID( OGRNullFID );

    if( nTotalShapeCount == 0
        && wkbFlatten(eRequestedGeomType) == wkbUnknown
        && poFeature->GetGeometryRef() != NULL )
    {
        OGRGeometry     *poGeom = poFeature->GetGeometryRef();
        int             nShapeType;

        switch( poGeom->getGeometryType() )
        {
          case wkbPoint:
            nShapeType = SHPT_POINT;
            eRequestedGeomType = wkbPoint;
            break;

          case wkbPoint25D:
            nShapeType = SHPT_POINTZ;
            eRequestedGeomType = wkbPoint25D;
            break;

          case wkbPointM:
            nShapeType = SHPT_POINTM;
            eRequestedGeomType = wkbPointM;
            break;

          case wkbPointZM:
            nShapeType = SHPT_POINTZ;
            eRequestedGeomType = wkbPointZM;
            break;

          case wkbMultiPoint:
            nShapeType = SHPT_MULTIPOINT;
            eRequestedGeomType = wkbMultiPoint;
            break;

          case wkbMultiPoint25D:
            nShapeType = SHPT_MULTIPOINTZ;
            eRequestedGeomType = wkbMultiPoint25D;
            break;

          case wkbMultiPointM:
            nShapeType = SHPT_MULTIPOINTM;
            eRequestedGeomType = wkbMultiPointM;
            break;

          case wkbMultiPointZM:
            nShapeType = SHPT_MULTIPOINTZ;
            eRequestedGeomType = wkbMultiPointM;
            break;

          case wkbLineString:
          case wkbMultiLineString:
            nShapeType = SHPT_ARC;
            eRequestedGeomType = wkbLineString;
            break;

          case wkbLineString25D:
          case wkbMultiLineString25D:
            nShapeType = SHPT_ARCZ;
            eRequestedGeomType = wkbLineString25D;
            break;

          case wkbLineStringM:
          case wkbMultiLineStringM:
            nShapeType = SHPT_ARCM;
            eRequestedGeomType = wkbLineStringM;
            break;

          case wkbLineStringZM:
          case wkbMultiLineStringZM:
            nShapeType = SHPT_ARCZ;
            eRequestedGeomType = wkbLineStringZM;
            break;

          case wkbPolygon:
          case wkbMultiPolygon:
            nShapeType = SHPT_POLYGON;
            eRequestedGeomType = wkbPolygon;
            break;

          case wkbPolygon25D:
          case wkbMultiPolygon25D:
            nShapeType = SHPT_POLYGONZ;
            eRequestedGeomType = wkbPolygon25D;
            break;

          case wkbPolygonM:
          case wkbMultiPolygonM:
            nShapeType = SHPT_POLYGONM;
            eRequestedGeomType = wkbPolygonM;
            break;

          case wkbPolygonZM:
          case wkbMultiPolygonZM:
            nShapeType = SHPT_POLYGONZ;
            eRequestedGeomType = wkbPolygonZM;
            break;

          default:
            nShapeType = -1;
            break;
        }

        if( nShapeType != -1 )
        {
            poFeatureDefn->SetGeomType(eRequestedGeomType);
            ResetGeomType( nShapeType );
        }
    }

    eErr = SHPWriteOGRFeature( hSHP, hDBF, poFeatureDefn, poFeature,
                               osEncoding, &bTruncationWarningEmitted,
                               bRewindOnWrite );

    if( hSHP != NULL )
        nTotalShapeCount = hSHP->nRecords;
    else
        nTotalShapeCount = hDBF->nRecords;

    return eErr;
}

/************************************************************************/
/*               GetFeatureCountWithSpatialFilterOnly()                 */
/*                                                                      */
/* Specialized implementation of GetFeatureCount() when there is *only* */
/* a spatial filter and no attribute filter.                            */
/************************************************************************/

int OGRShapeLayer::GetFeatureCountWithSpatialFilterOnly()

{
/* -------------------------------------------------------------------- */
/*      Collect a matching list if we have attribute or spatial         */
/*      indices.  Only do this on the first request for a given pass    */
/*      of course.                                                      */
/* -------------------------------------------------------------------- */
    if( panMatchingFIDs == NULL )
    {
        ScanIndices();
    }

    int nFeatureCount = 0;
    int iLocalMatchingFID = 0;
    int iLocalNextShapeId = 0;
    int bExpectPoints = FALSE;

    if (wkbFlatten(poFeatureDefn->GetGeomType()) == wkbPoint)
        bExpectPoints = TRUE;

/* -------------------------------------------------------------------- */
/*      Loop till we find a feature matching our criteria.              */
/* -------------------------------------------------------------------- */

    SHPObject sShape;
    memset(&sShape, 0, sizeof(sShape));

    while( true )
    {
        SHPObject* psShape = NULL;
        int iShape = -1;

        if( panMatchingFIDs != NULL )
        {
            iShape = (int)panMatchingFIDs[iLocalMatchingFID];
            if( iShape == OGRNullFID )
                break;
            iLocalMatchingFID++;
        }
        else
        {
            if( iLocalNextShapeId >= nTotalShapeCount )
                break;
            iShape = iLocalNextShapeId ++;

            if( hDBF )
            {
                if (DBFIsRecordDeleted( hDBF, iShape ))
                    continue;

                if (VSIFEofL(VSI_SHP_GetVSIL(hDBF->fp)))
                    break;
            }
        }

        /* Read full shape for point layers */
        if (bExpectPoints ||
            hSHP->panRecOffset[iShape] == 0 /* lazy shx loading case */ )
            psShape = SHPReadObject( hSHP, iShape);

/* -------------------------------------------------------------------- */
/*      Only read feature type and bounding box for now. In case of     */
/*      inconclusive tests on bounding box only, we will read the full  */
/*      shape later.                                                    */
/* -------------------------------------------------------------------- */
        else if (iShape >= 0 && iShape < hSHP->nRecords &&
                    hSHP->panRecSize[iShape] > 4 + 8 * 4 )
        {
            GByte abyBuf[4 + 8 * 4];
            if( hSHP->sHooks.FSeek( hSHP->fpSHP, hSHP->panRecOffset[iShape] + 8, 0 ) == 0 &&
                hSHP->sHooks.FRead( abyBuf, sizeof(abyBuf), 1, hSHP->fpSHP ) == 1 )
            {
                memcpy(&(sShape.nSHPType), abyBuf, 4);
                CPL_LSBPTR32(&(sShape.nSHPType));
                if ( sShape.nSHPType != SHPT_NULL &&
                        sShape.nSHPType != SHPT_POINT &&
                        sShape.nSHPType != SHPT_POINTM &&
                        sShape.nSHPType != SHPT_POINTZ)
                {
                    psShape = &sShape;
                    memcpy(&(sShape.dfXMin), abyBuf + 4, 8);
                    memcpy(&(sShape.dfYMin), abyBuf + 12, 8);
                    memcpy(&(sShape.dfXMax), abyBuf + 20, 8);
                    memcpy(&(sShape.dfYMax), abyBuf + 28, 8);
                    CPL_LSBPTR64(&(sShape.dfXMin));
                    CPL_LSBPTR64(&(sShape.dfYMin));
                    CPL_LSBPTR64(&(sShape.dfXMax));
                    CPL_LSBPTR64(&(sShape.dfYMax));
                }
            }
            else
            {
                break;
            }
        }

        if( psShape != NULL && psShape->nSHPType != SHPT_NULL )
        {
            OGRGeometry* poGeometry = NULL;
            OGREnvelope sGeomEnv;
            /* Test if we have a degenerated bounding box */
            if (psShape->nSHPType != SHPT_POINT
                && psShape->nSHPType != SHPT_POINTZ
                && psShape->nSHPType != SHPT_POINTM
                && (psShape->dfXMin == psShape->dfXMax
                    || psShape->dfYMin == psShape->dfYMax))
            {
                /* We need to read the full geometry */
                /* to compute the envelope */
                if (psShape == &sShape)
                    psShape = SHPReadObject( hSHP, iShape);
                if (psShape)
                {
                    poGeometry = SHPReadOGRObject( hSHP, iShape, psShape );
                    poGeometry->getEnvelope( &sGeomEnv );
                    psShape = NULL;
                }
            }
            else
            {
                /* Trust the shape bounding box as the shape envelope */
                sGeomEnv.MinX = psShape->dfXMin;
                sGeomEnv.MinY = psShape->dfYMin;
                sGeomEnv.MaxX = psShape->dfXMax;
                sGeomEnv.MaxY = psShape->dfYMax;
            }

/* -------------------------------------------------------------------- */
/*      If there is no                                                  */
/*      intersection between the envelopes we are sure not to have      */
/*      any intersection.                                               */
/* -------------------------------------------------------------------- */
            if( sGeomEnv.MaxX < m_sFilterEnvelope.MinX
                || sGeomEnv.MaxY < m_sFilterEnvelope.MinY
                || m_sFilterEnvelope.MaxX < sGeomEnv.MinX
                || m_sFilterEnvelope.MaxY < sGeomEnv.MinY )
            {
            }
/* -------------------------------------------------------------------- */
/*      If the filter geometry is its own envelope and if the           */
/*      envelope of the geometry is inside the filter geometry,         */
/*      the geometry itself is inside the filter geometry               */
/* -------------------------------------------------------------------- */
            else if( m_bFilterIsEnvelope &&
                sGeomEnv.MinX >= m_sFilterEnvelope.MinX &&
                sGeomEnv.MinY >= m_sFilterEnvelope.MinY &&
                sGeomEnv.MaxX <= m_sFilterEnvelope.MaxX &&
                sGeomEnv.MaxY <= m_sFilterEnvelope.MaxY)
            {
                nFeatureCount ++;
            }
            else
            {
/* -------------------------------------------------------------------- */
/*      Fallback to full intersect test (using GEOS) if we still        */
/*      don't know for sure.                                            */
/* -------------------------------------------------------------------- */
                if( OGRGeometryFactory::haveGEOS() )
                {
                    /* We need to read the full geometry */
                    if (poGeometry == NULL)
                    {
                        if (psShape == &sShape)
                            psShape = SHPReadObject( hSHP, iShape);
                        if (psShape)
                        {
                            poGeometry =
                                SHPReadOGRObject( hSHP, iShape, psShape );
                            psShape = NULL;
                        }
                    }
                    if( poGeometry == NULL )
                        nFeatureCount ++;
                    else if ( m_pPreparedFilterGeom != NULL )
                    {
                        if( OGRPreparedGeometryIntersects(m_pPreparedFilterGeom,
                                                          poGeometry) )
                        {
                            nFeatureCount ++;
                        }
                    }
                    else if( m_poFilterGeom->Intersects( poGeometry ) )
                        nFeatureCount ++;
                }
                else
                    nFeatureCount ++;
            }

            delete poGeometry;
        }
        else
            nFeatureCount ++;

        if (psShape && psShape != &sShape)
            SHPDestroyObject( psShape );
    }

    return nFeatureCount;
}

/************************************************************************/
/*                          GetFeatureCount()                           */
/************************************************************************/

GIntBig OGRShapeLayer::GetFeatureCount( int bForce )

{
    /* Check if the spatial filter is non-trivial */
    int bHasTrivialSpatialFilter;
    if (m_poFilterGeom != NULL)
    {
        OGREnvelope oSpatialFilterEnvelope;
        m_poFilterGeom->getEnvelope( &oSpatialFilterEnvelope );

        OGREnvelope oLayerExtent;
        if (GetExtent(&oLayerExtent, TRUE) == OGRERR_NONE)
        {
            if (oSpatialFilterEnvelope.Contains(oLayerExtent))
            {
                bHasTrivialSpatialFilter = TRUE;
            }
            else
                bHasTrivialSpatialFilter = FALSE;
        }
        else
            bHasTrivialSpatialFilter = FALSE;
    }
    else
        bHasTrivialSpatialFilter = TRUE;


    if( bHasTrivialSpatialFilter && m_poAttrQuery == NULL )
        return nTotalShapeCount;

    if (!TouchLayer())
        return 0;

    /* Spatial filter only */
    if( m_poAttrQuery == NULL && hSHP != NULL )
    {
        return GetFeatureCountWithSpatialFilterOnly();
    }

    /* Attribute filter only */
    if( m_poAttrQuery != NULL )
    {
        /* Let's see if we can ignore reading geometries */
        int bSaveGeometryIgnored = poFeatureDefn->IsGeometryIgnored();
        if (!AttributeFilterEvaluationNeedsGeometry())
            poFeatureDefn->SetGeometryIgnored(TRUE);

        GIntBig nRet = OGRLayer::GetFeatureCount( bForce );

        poFeatureDefn->SetGeometryIgnored(bSaveGeometryIgnored);
        return nRet;
    }

    return OGRLayer::GetFeatureCount( bForce );
}

/************************************************************************/
/*                             GetExtent()                              */
/*                                                                      */
/*      Fetch extent of the data currently stored in the dataset.       */
/*      The bForce flag has no effect on SHP files since that value     */
/*      is always in the header.                                        */
/*                                                                      */
/*      Returns OGRERR_NONE/OGRRERR_FAILURE.                            */
/************************************************************************/

OGRErr OGRShapeLayer::GetExtent (OGREnvelope *psExtent, int bForce)

{
    UNREFERENCED_PARAM( bForce );

    if (!TouchLayer())
        return OGRERR_FAILURE;

    double adMin[4], adMax[4];

    if( hSHP == NULL )
        return OGRERR_FAILURE;

    SHPGetInfo(hSHP, NULL, NULL, adMin, adMax);

    psExtent->MinX = adMin[0];
    psExtent->MinY = adMin[1];
    psExtent->MaxX = adMax[0];
    psExtent->MaxY = adMax[1];

    if( CPLIsNan(adMin[0]) || CPLIsNan(adMin[1]) ||
        CPLIsNan(adMax[0]) || CPLIsNan(adMax[1]) )
    {
        CPLDebug("SHAPE", "Invalid extent in shape header");
        OGRErr eErr;

        /* Disable filters to avoid infinite recursion in GetNextFeature() */
        /* that calls ScanIndices() that call GetExtent... */
        OGRFeatureQuery* poAttrQuery = m_poAttrQuery;
        m_poAttrQuery = NULL;
        OGRGeometry* poFilterGeom = m_poFilterGeom;
        m_poFilterGeom = NULL;

        eErr = OGRLayer::GetExtent(psExtent, bForce);

        m_poAttrQuery = poAttrQuery;
        m_poFilterGeom = poFilterGeom;
        return eErr;
    }

    return OGRERR_NONE;
}

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

int OGRShapeLayer::TestCapability( const char * pszCap )

{
    if (!TouchLayer())
        return FALSE;

    if( EQUAL(pszCap,OLCRandomRead) )
        return TRUE;

    else if( EQUAL(pszCap,OLCSequentialWrite)
             || EQUAL(pszCap,OLCRandomWrite) )
        return bUpdateAccess;

    else if( EQUAL(pszCap,OLCFastFeatureCount) )
    {
        if( !(m_poFilterGeom == NULL || CheckForQIX() || CheckForSBN()) )
            return FALSE;

        if( m_poAttrQuery != NULL )
        {
            InitializeIndexSupport( pszFullName );
            return m_poAttrQuery->CanUseIndex(this);
        }
        return TRUE;
    }

    else if( EQUAL(pszCap,OLCDeleteFeature) )
        return bUpdateAccess;

    else if( EQUAL(pszCap,OLCFastSpatialFilter) )
        return CheckForQIX() || CheckForSBN();

    else if( EQUAL(pszCap,OLCFastGetExtent) )
        return TRUE;

    else if( EQUAL(pszCap,OLCFastSetNextByIndex) )
        return m_poFilterGeom == NULL && m_poAttrQuery == NULL;

    else if( EQUAL(pszCap,OLCCreateField) )
        return bUpdateAccess;

    else if( EQUAL(pszCap,OLCDeleteField) )
        return bUpdateAccess;

    else if( EQUAL(pszCap,OLCReorderFields) )
        return bUpdateAccess;

    else if( EQUAL(pszCap,OLCAlterFieldDefn) )
        return bUpdateAccess;

    else if( EQUAL(pszCap,OLCIgnoreFields) )
        return TRUE;

    else if( EQUAL(pszCap,OLCStringsAsUTF8) )
    {
        /* No encoding defined : we don't know */
        if( osEncoding.size() == 0)
            return FALSE;

        if( hDBF == NULL || DBFGetFieldCount( hDBF ) == 0 )
            return TRUE;

        CPLClearRecodeWarningFlags();

        /* Otherwise test that we can re-encode field names to UTF-8 */
        int nFieldCount = DBFGetFieldCount( hDBF );
        for(int i=0;i<nFieldCount;i++)
        {
            char            szFieldName[20];
            int             nWidth, nPrecision;

            DBFGetFieldInfo( hDBF, i, szFieldName,
                            &nWidth, &nPrecision );

            CPLErrorReset();
            CPLPushErrorHandler(CPLQuietErrorHandler);
            char *pszUTF8Field = CPLRecode( szFieldName,
                                            osEncoding, CPL_ENC_UTF8);
            CPLPopErrorHandler();
            CPLFree( pszUTF8Field );

            if (CPLGetLastErrorType() != 0)
            {
                return FALSE;
            }
        }

        return TRUE;
    }

    else if( EQUAL(pszCap,OLCMeasuredGeometries) )
        return TRUE;

    else
        return FALSE;
}

/************************************************************************/
/*                            CreateField()                             */
/************************************************************************/

OGRErr OGRShapeLayer::CreateField( OGRFieldDefn *poFieldDefn, int bApproxOK )

{
    if (!TouchLayer())
        return OGRERR_FAILURE;

    CPLAssert( NULL != poFieldDefn );

    int         iNewField;

    if( !bUpdateAccess )
    {
        CPLError( CE_Failure, CPLE_NotSupported,
                  UNSUPPORTED_OP_READ_ONLY,
                  "CreateField");
        return OGRERR_FAILURE;

    }

    int bDBFJustCreated = FALSE;
    if( hDBF == NULL )
    {
        CPLString osFilename = CPLResetExtension( pszFullName, "dbf" );
        hDBF = DBFCreate( osFilename );

        if( hDBF == NULL )
        {
            CPLError( CE_Failure, CPLE_OpenFailed,
                      "Failed to create DBF file `%s'.\n",
                      osFilename.c_str() );
            return OGRERR_FAILURE;
        }

        bDBFJustCreated = TRUE;
    }

    CPLErrorReset();

    if ( poFeatureDefn->GetFieldCount() == 255 )
    {
        CPLError( CE_Warning, CPLE_AppDefined,
                  "Creating a 256th field, but some DBF readers might only support 255 fields" );
    }
    if ( hDBF->nHeaderLength + 32 > 65535 )
    {
        CPLError( CE_Failure, CPLE_NotSupported,
                  "Cannot add more fields in DBF file.");
        return OGRERR_FAILURE;
    }

/* -------------------------------------------------------------------- */
/*      Normalize field name                                            */
/* -------------------------------------------------------------------- */

    char szNewFieldName[10 + 1];
    char * pszTmp = NULL;
    int nRenameNum = 1;

    CPLString osFieldName;
    if( osEncoding.size() )
    {
        CPLClearRecodeWarningFlags();
        CPLPushErrorHandler(CPLQuietErrorHandler);
        CPLErr eLastErr = CPLGetLastErrorType();
        char* pszRecoded = CPLRecode( poFieldDefn->GetNameRef(), CPL_ENC_UTF8, osEncoding);
        CPLPopErrorHandler();
        osFieldName = pszRecoded;
        CPLFree(pszRecoded);
        if( CPLGetLastErrorType() != eLastErr )
        {
            CPLError(CE_Failure, CPLE_AppDefined,
                     "Failed to create field name '%s' : cannot convert to %s",
                     poFieldDefn->GetNameRef(), osEncoding.c_str());
            return OGRERR_FAILURE;
        }
    }
    else
        osFieldName = poFieldDefn->GetNameRef();

    int nNameSize = static_cast<int>(osFieldName.size());
    pszTmp = CPLScanString( osFieldName,
                            MIN( nNameSize, 10) , TRUE, TRUE);
    strncpy(szNewFieldName, pszTmp, 10);
    szNewFieldName[10] = '\0';

    if( !bApproxOK &&
        ( DBFGetFieldIndex( hDBF, szNewFieldName ) >= 0 ||
          !EQUAL(osFieldName,szNewFieldName) ) )
    {
        CPLError( CE_Failure, CPLE_NotSupported,
                  "Failed to add field named '%s'",
                  poFieldDefn->GetNameRef() );

        CPLFree( pszTmp );
        return OGRERR_FAILURE;
    }

    while( DBFGetFieldIndex( hDBF, szNewFieldName ) >= 0 && nRenameNum < 10 )
        snprintf( szNewFieldName, sizeof(szNewFieldName), "%.8s_%.1d", pszTmp, nRenameNum++ );
    while( DBFGetFieldIndex( hDBF, szNewFieldName ) >= 0 && nRenameNum < 100 )
        snprintf( szNewFieldName, sizeof(szNewFieldName), "%.8s%.2d", pszTmp, nRenameNum++ );

    CPLFree( pszTmp );
    pszTmp = NULL;

    if( DBFGetFieldIndex( hDBF, szNewFieldName ) >= 0 )
    {
        CPLError( CE_Failure, CPLE_NotSupported,
                  "Too many field names like '%s' when truncated to 10 letters "
                  "for Shapefile format.",
                  poFieldDefn->GetNameRef() );//One hundred similar field names!!?
    }

    OGRFieldDefn oModFieldDefn(poFieldDefn);

    if( !EQUAL(osFieldName,szNewFieldName) )
    {
        CPLError( CE_Warning, CPLE_NotSupported,
                  "Normalized/laundered field name: '%s' to '%s'",
                  poFieldDefn->GetNameRef(),
                  szNewFieldName );

        // Set field name with normalized value
        oModFieldDefn.SetName(szNewFieldName);
    }

/* -------------------------------------------------------------------- */
/*      Add field to layer                                              */
/* -------------------------------------------------------------------- */

    char chType = 'C';
    int nWidth = 0;
    int nDecimals = 0;

    switch( oModFieldDefn.GetType() )
    {
        case OFTInteger:
            chType = 'N';
            nWidth = oModFieldDefn.GetWidth();
            if (nWidth == 0) nWidth = 9;
            break;

        case OFTInteger64:
            chType = 'N';
            nWidth = oModFieldDefn.GetWidth();
            if (nWidth == 0) nWidth = 18;
            break;

        case OFTReal:
            chType = 'N';
            nWidth = oModFieldDefn.GetWidth();
            nDecimals = oModFieldDefn.GetPrecision();
            if (nWidth == 0)
            {
                nWidth = 24;
                nDecimals = 15;
            }
            break;

        case OFTString:
            chType = 'C';
            nWidth = oModFieldDefn.GetWidth();
            if (nWidth == 0) nWidth = 80;
            else if (nWidth > OGR_DBF_MAX_FIELD_WIDTH)
            {
                CPLError( CE_Warning, CPLE_AppDefined,
                        "Field %s of width %d truncated to %d.",
                        szNewFieldName, nWidth, OGR_DBF_MAX_FIELD_WIDTH );
                nWidth = OGR_DBF_MAX_FIELD_WIDTH;
            }
            break;

        case OFTDate:
            chType = 'D';
            nWidth = 8;
            break;

        case OFTDateTime:
            CPLError( CE_Warning, CPLE_NotSupported,
                    "Field %s create as date field, though DateTime requested.",
                    szNewFieldName );
            chType = 'D';
            nWidth = 8;
            oModFieldDefn.SetType( OFTDate );
            break;

        default:
            CPLError( CE_Failure, CPLE_NotSupported,
                    "Can't create fields of type %s on shapefile layers.",
                    OGRFieldDefn::GetFieldTypeName(oModFieldDefn.GetType()) );

            return OGRERR_FAILURE;
            break;
    }

    oModFieldDefn.SetWidth( nWidth );
    oModFieldDefn.SetPrecision( nDecimals );

    if ( hDBF->nRecordLength + nWidth > 65535 )
    {
        CPLError( CE_Failure, CPLE_NotSupported,
                  "Can't create field %s in Shape DBF file. "
                  "Maximum record length reached.",
                  szNewFieldName );
        return OGRERR_FAILURE;
    }

    /* Suppress the dummy FID field if we have created it just before */
    if( DBFGetFieldCount( hDBF ) == 1 && poFeatureDefn->GetFieldCount() == 0 )
    {
        DBFDeleteField( hDBF, 0 );
    }

    iNewField =
        DBFAddNativeFieldType( hDBF, szNewFieldName,
                               chType, nWidth, nDecimals );

    if( iNewField != -1 )
    {
        poFeatureDefn->AddFieldDefn( &oModFieldDefn );

        if( bDBFJustCreated )
        {
            for(int i=0;i<nTotalShapeCount;i++)
            {
                DBFWriteNULLAttribute( hDBF, i, 0 );
            }
        }

        return OGRERR_NONE;
    }
    else
    {
        CPLError( CE_Failure, CPLE_AppDefined,
                  "Can't create field %s in Shape DBF file, reason unknown.",
                  szNewFieldName );

        return OGRERR_FAILURE;
    }
}

/************************************************************************/
/*                            DeleteField()                             */
/************************************************************************/

OGRErr OGRShapeLayer::DeleteField( int iField )
{
    if (!TouchLayer())
        return OGRERR_FAILURE;

    if( !bUpdateAccess )
    {
        CPLError( CE_Failure, CPLE_NotSupported,
                  UNSUPPORTED_OP_READ_ONLY,
                  "DeleteField");
        return OGRERR_FAILURE;
    }

    if (iField < 0 || iField >= poFeatureDefn->GetFieldCount())
    {
        CPLError( CE_Failure, CPLE_NotSupported,
                  "Invalid field index");
        return OGRERR_FAILURE;
    }

    if ( DBFDeleteField( hDBF, iField ) )
    {
        TruncateDBF();

        return poFeatureDefn->DeleteFieldDefn( iField );
    }
    else
        return OGRERR_FAILURE;
}

/************************************************************************/
/*                           ReorderFields()                            */
/************************************************************************/

OGRErr OGRShapeLayer::ReorderFields( int* panMap )
{
    if (!TouchLayer())
        return OGRERR_FAILURE;

    if( !bUpdateAccess )
    {
        CPLError( CE_Failure, CPLE_NotSupported,
                  UNSUPPORTED_OP_READ_ONLY,
                  "ReorderFields");
        return OGRERR_FAILURE;
    }

    if (poFeatureDefn->GetFieldCount() == 0)
        return OGRERR_NONE;

    OGRErr eErr = OGRCheckPermutation(panMap, poFeatureDefn->GetFieldCount());
    if (eErr != OGRERR_NONE)
        return eErr;

    if ( DBFReorderFields( hDBF, panMap ) )
    {
        return poFeatureDefn->ReorderFieldDefns( panMap );
    }
    else
        return OGRERR_FAILURE;
}

/************************************************************************/
/*                           AlterFieldDefn()                           */
/************************************************************************/

OGRErr OGRShapeLayer::AlterFieldDefn( int iField, OGRFieldDefn* poNewFieldDefn, int nFlagsIn )
{
    if (!TouchLayer())
        return OGRERR_FAILURE;

    if( !bUpdateAccess )
    {
        CPLError( CE_Failure, CPLE_NotSupported,
                  UNSUPPORTED_OP_READ_ONLY,
                  "AlterFieldDefn");
        return OGRERR_FAILURE;
    }

    if (iField < 0 || iField >= poFeatureDefn->GetFieldCount())
    {
        CPLError( CE_Failure, CPLE_NotSupported,
                  "Invalid field index");
        return OGRERR_FAILURE;
    }

    OGRFieldDefn* poFieldDefn = poFeatureDefn->GetFieldDefn(iField);

    char chNativeType;
    char            szFieldName[20];
    int             nWidth, nPrecision;
    OGRFieldType    eType = poFieldDefn->GetType();
    /* DBFFieldType    eDBFType; */

    chNativeType = DBFGetNativeFieldType( hDBF, iField );
    /* eDBFType = */ DBFGetFieldInfo( hDBF, iField, szFieldName,
                                      &nWidth, &nPrecision );

    if ((nFlagsIn & ALTER_TYPE_FLAG) &&
        poNewFieldDefn->GetType() != poFieldDefn->GetType())
    {
        if (poNewFieldDefn->GetType() == OFTInteger64 && poFieldDefn->GetType() == OFTInteger )
        {
            eType = poNewFieldDefn->GetType();
        }
        else if (poNewFieldDefn->GetType() != OFTString)
        {
            CPLError( CE_Failure, CPLE_NotSupported,
                      "Can only convert to OFTString");
            return OGRERR_FAILURE;
        }
        else
        {
            chNativeType = 'C';
            eType = poNewFieldDefn->GetType();
        }
    }

    if (nFlagsIn & ALTER_NAME_FLAG)
    {
        CPLString osFieldName;
        if( osEncoding.size() )
        {
            CPLClearRecodeWarningFlags();
            CPLErrorReset();
            CPLPushErrorHandler(CPLQuietErrorHandler);
            char* pszRecoded = CPLRecode( poNewFieldDefn->GetNameRef(), CPL_ENC_UTF8, osEncoding);
            CPLPopErrorHandler();
            osFieldName = pszRecoded;
            CPLFree(pszRecoded);
            if( CPLGetLastErrorType() != 0 )
            {
                CPLError(CE_Failure, CPLE_AppDefined,
                        "Failed to rename field name to '%s' : cannot convert to %s",
                        poNewFieldDefn->GetNameRef(), osEncoding.c_str());
                return OGRERR_FAILURE;
            }
        }
        else
            osFieldName = poNewFieldDefn->GetNameRef();

        strncpy(szFieldName, osFieldName, 10);
        szFieldName[10] = '\0';
    }
    if (nFlagsIn & ALTER_WIDTH_PRECISION_FLAG)
    {
        nWidth = poNewFieldDefn->GetWidth();
        nPrecision = poNewFieldDefn->GetPrecision();
    }

    if ( DBFAlterFieldDefn( hDBF, iField, szFieldName,
                            chNativeType, nWidth, nPrecision) )
    {
        if (nFlagsIn & ALTER_TYPE_FLAG)
            poFieldDefn->SetType(eType);
        if (nFlagsIn & ALTER_NAME_FLAG)
            poFieldDefn->SetName(poNewFieldDefn->GetNameRef());
        if (nFlagsIn & ALTER_WIDTH_PRECISION_FLAG)
        {
            poFieldDefn->SetWidth(nWidth);
            poFieldDefn->SetPrecision(nPrecision);

            TruncateDBF();
        }
        return OGRERR_NONE;
    }
    else
        return OGRERR_FAILURE;
}

/************************************************************************/
/*                           GetSpatialRef()                            */
/************************************************************************/

OGRSpatialReference *OGRShapeGeomFieldDefn::GetSpatialRef()

{
    if (bSRSSet)
        return poSRS;

    bSRSSet = TRUE;

/* -------------------------------------------------------------------- */
/*      Is there an associated .prj file we can read?                   */
/* -------------------------------------------------------------------- */
    const char  *pszPrjFile = CPLResetExtension( pszFullName, "prj" );
    char    **papszLines;

    char* apszOptions[] = { (char*)"EMIT_ERROR_IF_CANNOT_OPEN_FILE=FALSE", NULL };
    papszLines = CSLLoad2( pszPrjFile, -1, -1, apszOptions );
    if (papszLines == NULL)
    {
        pszPrjFile = CPLResetExtension( pszFullName, "PRJ" );
        papszLines = CSLLoad2( pszPrjFile, -1, -1, apszOptions );
    }

    if( papszLines != NULL )
    {
        osPrjFile = pszPrjFile;

        poSRS = new OGRSpatialReference();
        /* Remove UTF-8 BOM if found */
        /* http://lists.osgeo.org/pipermail/gdal-dev/2014-July/039527.html */
        if( ((unsigned char)papszLines[0][0] == 0xEF) &&
            ((unsigned char)papszLines[0][1] == 0xBB) &&
            ((unsigned char)papszLines[0][2] == 0xBF) )
        {
            memmove(papszLines[0], papszLines[0] + 3, strlen(papszLines[0] + 3) + 1);
        }
        if( poSRS->importFromESRI( papszLines ) != OGRERR_NONE )
        {
            delete poSRS;
            poSRS = NULL;
        }
        CSLDestroy( papszLines );
    }

    return poSRS;
}

/************************************************************************/
/*                           ResetGeomType()                            */
/*                                                                      */
/*      Modify the geometry type for this file.  Used to convert to     */
/*      a different geometry type when a layer was created with a       */
/*      type of unknown, and we get to the first feature to             */
/*      establish the type.                                             */
/************************************************************************/

int OGRShapeLayer::ResetGeomType( int nNewGeomType )

{
    char        abyHeader[100];
    int         nStartPos;

    if( nTotalShapeCount > 0 )
        return FALSE;

    if( hSHP->fpSHX == NULL)
    {
        CPLError( CE_Failure, CPLE_NotSupported,
                  " OGRShapeLayer::ResetGeomType failed : SHX file is closed");
        return FALSE;
    }

/* -------------------------------------------------------------------- */
/*      Update .shp header.                                             */
/* -------------------------------------------------------------------- */
    nStartPos = (int)( hSHP->sHooks.FTell( hSHP->fpSHP ) );

    if( hSHP->sHooks.FSeek( hSHP->fpSHP, 0, SEEK_SET ) != 0
        || hSHP->sHooks.FRead( abyHeader, 100, 1, hSHP->fpSHP ) != 1 )
        return FALSE;

    *((GInt32 *) (abyHeader + 32)) = CPL_LSBWORD32( nNewGeomType );

    if( hSHP->sHooks.FSeek( hSHP->fpSHP, 0, SEEK_SET ) != 0
        || hSHP->sHooks.FWrite( abyHeader, 100, 1, hSHP->fpSHP ) != 1 )
        return FALSE;

    if( hSHP->sHooks.FSeek( hSHP->fpSHP, nStartPos, SEEK_SET ) != 0 )
        return FALSE;

/* -------------------------------------------------------------------- */
/*      Update .shx header.                                             */
/* -------------------------------------------------------------------- */
    nStartPos = (int)( hSHP->sHooks.FTell( hSHP->fpSHX ) );

    if( hSHP->sHooks.FSeek( hSHP->fpSHX, 0, SEEK_SET ) != 0
        || hSHP->sHooks.FRead( abyHeader, 100, 1, hSHP->fpSHX ) != 1 )
        return FALSE;

    *((GInt32 *) (abyHeader + 32)) = CPL_LSBWORD32( nNewGeomType );

    if( hSHP->sHooks.FSeek( hSHP->fpSHX, 0, SEEK_SET ) != 0
        || hSHP->sHooks.FWrite( abyHeader, 100, 1, hSHP->fpSHX ) != 1 )
        return FALSE;

    if( hSHP->sHooks.FSeek( hSHP->fpSHX, nStartPos, SEEK_SET ) != 0 )
        return FALSE;

/* -------------------------------------------------------------------- */
/*      Update other information.                                       */
/* -------------------------------------------------------------------- */
    hSHP->nShapeType = nNewGeomType;

    return TRUE;
}

/************************************************************************/
/*                             SyncToDisk()                             */
/************************************************************************/

OGRErr OGRShapeLayer::SyncToDisk()

{
    if (!TouchLayer())
        return OGRERR_FAILURE;

    if( bHeaderDirty )
    {
        if( hSHP != NULL )
            SHPWriteHeader( hSHP );

        if( hDBF != NULL )
            DBFUpdateHeader( hDBF );

        bHeaderDirty = FALSE;
    }

    if( hSHP != NULL )
    {
        hSHP->sHooks.FFlush( hSHP->fpSHP );
        if( hSHP->fpSHX != NULL )
            hSHP->sHooks.FFlush( hSHP->fpSHX );
    }

    if( hDBF != NULL )
    {
        hDBF->sHooks.FFlush( hDBF->fp );
    }

    return OGRERR_NONE;
}

/************************************************************************/
/*                          DropSpatialIndex()                          */
/************************************************************************/

OGRErr OGRShapeLayer::DropSpatialIndex()

{
    if (!TouchLayer())
        return OGRERR_FAILURE;

    if( !CheckForQIX() && !CheckForSBN() )
    {
        CPLError( CE_Warning, CPLE_AppDefined,
                  "Layer %s has no spatial index, DROP SPATIAL INDEX failed.",
                  poFeatureDefn->GetName() );
        return OGRERR_FAILURE;
    }

    int bHadQIX = hQIX != NULL;

    SHPCloseDiskTree( hQIX );
    hQIX = NULL;
    bCheckedForQIX = FALSE;

    SBNCloseDiskTree( hSBN );
    hSBN = NULL;
    bCheckedForSBN = FALSE;

    if( bHadQIX )
    {
        const char *pszQIXFilename;

        pszQIXFilename = CPLResetExtension( pszFullName, "qix" );
        CPLDebug( "SHAPE", "Unlinking index file %s", pszQIXFilename );

        if( VSIUnlink( pszQIXFilename ) != 0 )
        {
            CPLError( CE_Failure, CPLE_AppDefined,
                    "Failed to delete file %s.\n%s",
                    pszQIXFilename, VSIStrerror( errno ) );
            return OGRERR_FAILURE;
        }
    }

    if( !bSbnSbxDeleted )
    {
        const char *pszIndexFilename;
        const char papszExt[2][4] = { "sbn", "sbx" };
        int i;
        for( i = 0; i < 2; i++ )
        {
            pszIndexFilename = CPLResetExtension( pszFullName, papszExt[i] );
            CPLDebug( "SHAPE", "Trying to unlink index file %s", pszIndexFilename );

            if( VSIUnlink( pszIndexFilename ) != 0 )
            {
                CPLDebug( "SHAPE",
                          "Failed to delete file %s.\n%s",
                          pszIndexFilename, VSIStrerror( errno ) );
            }
        }
    }
    bSbnSbxDeleted = TRUE;

    ClearSpatialFIDs();

    return OGRERR_NONE;
}

/************************************************************************/
/*                         CreateSpatialIndex()                         */
/************************************************************************/

OGRErr OGRShapeLayer::CreateSpatialIndex( int nMaxDepth )

{
    if (!TouchLayer())
        return OGRERR_FAILURE;

/* -------------------------------------------------------------------- */
/*      If we have an existing spatial index, blow it away first.       */
/* -------------------------------------------------------------------- */
    if( CheckForQIX() )
        DropSpatialIndex();

    bCheckedForQIX = FALSE;

/* -------------------------------------------------------------------- */
/*      Build a quadtree structure for this file.                       */
/* -------------------------------------------------------------------- */
    SHPTree	*psTree;

    SyncToDisk();
    psTree = SHPCreateTree( hSHP, 2, nMaxDepth, NULL, NULL );

    if( NULL == psTree )
    {
        // TODO - mloskot: Is it better to return OGRERR_NOT_ENOUGH_MEMORY?

        CPLDebug( "SHAPE",
                  "Index creation failure. Likely, memory allocation error." );

        return OGRERR_FAILURE;
    }

/* -------------------------------------------------------------------- */
/*      Trim unused nodes from the tree.                                */
/* -------------------------------------------------------------------- */
    SHPTreeTrimExtraNodes( psTree );

/* -------------------------------------------------------------------- */
/*      Dump tree to .qix file.                                         */
/* -------------------------------------------------------------------- */
    char *pszQIXFilename;

    pszQIXFilename = CPLStrdup(CPLResetExtension( pszFullName, "qix" ));

    CPLDebug( "SHAPE", "Creating index file %s", pszQIXFilename );

    SHPWriteTree( psTree, pszQIXFilename );
    CPLFree( pszQIXFilename );


/* -------------------------------------------------------------------- */
/*      cleanup                                                         */
/* -------------------------------------------------------------------- */
    SHPDestroyTree( psTree );

    CheckForQIX();

    return OGRERR_NONE;
}

/************************************************************************/
/*                               Repack()                               */
/*                                                                      */
/*      Repack the shape and dbf file, dropping deleted records.        */
/*      FIDs may change.                                                */
/************************************************************************/

OGRErr OGRShapeLayer::Repack()

{
    if (!TouchLayer())
        return OGRERR_FAILURE;

    if( !bUpdateAccess )
    {
        CPLError( CE_Failure, CPLE_NotSupported,
                  UNSUPPORTED_OP_READ_ONLY,
                  "Repack");
        return OGRERR_FAILURE;
    }

/* -------------------------------------------------------------------- */
/*      Build a list of records to be dropped.                          */
/* -------------------------------------------------------------------- */
    int *panRecordsToDelete = (int*) CPLMalloc(sizeof(int)*128);
    int nDeleteCount = 0, nDeleteCountAlloc = 128;
    int iShape = 0;
    OGRErr eErr = OGRERR_NONE;

    if( hDBF != NULL )
    {
        for( iShape = 0; iShape < nTotalShapeCount; iShape++ )
        {
            if( DBFIsRecordDeleted( hDBF, iShape ) )
            {
                if( nDeleteCount == nDeleteCountAlloc )
                {
                    int nDeleteCountAllocNew =
                        nDeleteCountAlloc + nDeleteCountAlloc / 3 + 32;
                    if( nDeleteCountAlloc >= (INT_MAX - 32) / 4 * 3 ||
                        nDeleteCountAllocNew > INT_MAX / (int)sizeof(int) )
                    {
                        CPLError( CE_Failure, CPLE_AppDefined,
                                "Too many features to delete : %d", nDeleteCount );
                        CPLFree( panRecordsToDelete );
                        return OGRERR_FAILURE;
                    }
                    nDeleteCountAlloc = nDeleteCountAllocNew;
                    int* panRecordsToDeleteNew = (int*) VSI_REALLOC_VERBOSE(
                        panRecordsToDelete, nDeleteCountAlloc * sizeof(int) );
                    if( panRecordsToDeleteNew == NULL )
                    {
                        CPLFree( panRecordsToDelete );
                        return OGRERR_FAILURE;
                    }
                    panRecordsToDelete = panRecordsToDeleteNew;
                }
                panRecordsToDelete[nDeleteCount++] = iShape;
            }
            if( VSIFEofL(VSI_SHP_GetVSIL(hDBF->fp)) )
            {
                CPLFree( panRecordsToDelete );
                return OGRERR_FAILURE; /* There's an I/O error */
            }
        }
    }

/* -------------------------------------------------------------------- */
/*      If there are no records marked for deletion, we take no         */
/*      action.                                                         */
/* -------------------------------------------------------------------- */
    if( nDeleteCount == 0 && !bSHPNeedsRepack )
    {
        CPLFree( panRecordsToDelete );
        return OGRERR_NONE;
    }
    panRecordsToDelete[nDeleteCount] = -1;

/* -------------------------------------------------------------------- */
/*      Find existing filenames with exact case (see #3293).            */
/* -------------------------------------------------------------------- */
    CPLString osDirname(CPLGetPath(pszFullName));
    CPLString osBasename(CPLGetBasename(pszFullName));

    CPLString osDBFName, osSHPName, osSHXName, osCPGName;
    char **papszCandidates = VSIReadDir( osDirname );
    int i = 0;
    while(papszCandidates != NULL && papszCandidates[i] != NULL)
    {
        CPLString osCandidateBasename = CPLGetBasename(papszCandidates[i]);
        CPLString osCandidateExtension = CPLGetExtension(papszCandidates[i]);
#ifdef WIN32
        /* On Windows, as filenames are case insensitive, a shapefile layer can be made of */
        /* foo.shp and FOO.DBF, so use case insensitive comparison */
        if (EQUAL(osCandidateBasename, osBasename))
#else
        if (osCandidateBasename.compare(osBasename) == 0)
#endif
        {
            if (EQUAL(osCandidateExtension, "dbf"))
                osDBFName = CPLFormFilename(osDirname, papszCandidates[i], NULL);
            else if (EQUAL(osCandidateExtension, "shp"))
                osSHPName = CPLFormFilename(osDirname, papszCandidates[i], NULL);
            else if (EQUAL(osCandidateExtension, "shx"))
                osSHXName = CPLFormFilename(osDirname, papszCandidates[i], NULL);
            else if (EQUAL(osCandidateExtension, "cpg"))
                osCPGName = CPLFormFilename(osDirname, papszCandidates[i], NULL);
        }

        i++;
    }
    CSLDestroy(papszCandidates);
    papszCandidates = NULL;

    if( hDBF != NULL && osDBFName.size() == 0)
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "Cannot find the filename of the DBF file, but we managed to open it before !");
        /* Should not happen, really */
        CPLFree( panRecordsToDelete );
        return OGRERR_FAILURE;
    }

    if( hSHP != NULL && osSHPName.size() == 0 )
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "Cannot find the filename of the SHP file, but we managed to open it before !");
        /* Should not happen, really */
        CPLFree( panRecordsToDelete );
        return OGRERR_FAILURE;
    }

    if( hSHP != NULL && osSHXName.size() == 0 )
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "Cannot find the filename of the SHX file, but we managed to open it before !");
        /* Should not happen, really */
        CPLFree( panRecordsToDelete );
        return OGRERR_FAILURE;
    }

/* -------------------------------------------------------------------- */
/*      Cleanup any existing spatial index.  It will become             */
/*      meaningless when the fids change.                               */
/* -------------------------------------------------------------------- */
    if( CheckForQIX() || CheckForSBN() )
        DropSpatialIndex();

/* -------------------------------------------------------------------- */
/*      Create a new dbf file, matching the old.                        */
/* -------------------------------------------------------------------- */
    int bMustReopenDBF = FALSE;

    if( hDBF != NULL && nDeleteCount > 0 )
    {
        bMustReopenDBF = TRUE;

        CPLString oTempFile(CPLFormFilename(osDirname, osBasename, NULL));
        oTempFile += "_packed.dbf";

        DBFHandle hNewDBF = DBFCloneEmpty( hDBF, oTempFile );
        if( hNewDBF == NULL )
        {
            CPLFree( panRecordsToDelete );

            CPLError( CE_Failure, CPLE_OpenFailed,
                    "Failed to create temp file %s.",
                    oTempFile.c_str() );
            return OGRERR_FAILURE;
        }

        /* Delete temporary .cpg file if existing */
        if( osCPGName.size() )
        {
            CPLString oCPGTempFile = CPLFormFilename(osDirname, osBasename, NULL);
            oCPGTempFile += "_packed.cpg";
            if( VSIUnlink( oCPGTempFile ) != 0 )
            {
                CPLDebug( "Shape", "Did not manage to remove temporary .cpg file: %s",
                        VSIStrerror( errno ) );
            }
        }

/* -------------------------------------------------------------------- */
/*      Copy over all records that are not deleted.                     */
/* -------------------------------------------------------------------- */
        int iDestShape = 0;
        int iNextDeletedShape = 0;

        for( iShape = 0;
            iShape < nTotalShapeCount && eErr == OGRERR_NONE;
            iShape++ )
        {
            if( panRecordsToDelete[iNextDeletedShape] == iShape )
                iNextDeletedShape++;
            else
            {
                void *pTuple = (void *) DBFReadTuple( hDBF, iShape );
                if( pTuple == NULL )
                    eErr = OGRERR_FAILURE;
                else if( !DBFWriteTuple( hNewDBF, iDestShape++, pTuple ) )
                    eErr = OGRERR_FAILURE;
            }
        }

        if( eErr != OGRERR_NONE )
        {
            CPLFree( panRecordsToDelete );
            VSIUnlink( oTempFile );
            DBFClose( hNewDBF );
            return eErr;
        }

/* -------------------------------------------------------------------- */
/*      Cleanup the old .dbf and rename the new one.                    */
/* -------------------------------------------------------------------- */
        DBFClose( hDBF );
        DBFClose( hNewDBF );
        hDBF = hNewDBF = NULL;

        if( VSIUnlink( osDBFName ) != 0 )
        {
            CPLDebug( "Shape", "Failed to delete DBF file: %s", VSIStrerror( errno ) );
            CPLFree( panRecordsToDelete );

            hDBF = poDS->DS_DBFOpen ( osDBFName, bUpdateAccess ? "r+" : "r" );

            VSIUnlink( oTempFile );

            return OGRERR_FAILURE;
        }

        if( VSIRename( oTempFile, osDBFName ) != 0 )
        {
            CPLDebug( "Shape", "Can not rename DBF file: %s", VSIStrerror( errno ) );
            CPLFree( panRecordsToDelete );
            return OGRERR_FAILURE;
        }
    }

/* -------------------------------------------------------------------- */
/*      Now create a shapefile matching the old one.                    */
/* -------------------------------------------------------------------- */
    int bMustReopenSHP = ( hSHP != NULL );

    if( hSHP != NULL )
    {
        SHPHandle hNewSHP = NULL;

        CPLString oTempFile = CPLFormFilename(osDirname, osBasename, NULL);
        oTempFile += "_packed.shp";

        hNewSHP = SHPCreate( oTempFile, hSHP->nShapeType );
        if( hNewSHP == NULL )
        {
            CPLFree( panRecordsToDelete );
            return OGRERR_FAILURE;
        }

/* -------------------------------------------------------------------- */
/*      Copy over all records that are not deleted.                     */
/* -------------------------------------------------------------------- */
        int iNextDeletedShape = 0;

        for( iShape = 0;
             iShape < nTotalShapeCount && eErr == OGRERR_NONE;
             iShape++ )
        {
            if( panRecordsToDelete[iNextDeletedShape] == iShape )
                iNextDeletedShape++;
            else
            {
                SHPObject *hObject;

                hObject = SHPReadObject( hSHP, iShape );
                if( hObject == NULL )
                    eErr = OGRERR_FAILURE;
                else if( SHPWriteObject( hNewSHP, -1, hObject ) == -1 )
                    eErr = OGRERR_FAILURE;

                if( hObject )
                    SHPDestroyObject( hObject );
            }
        }

        if( eErr != OGRERR_NONE )
        {
            CPLFree( panRecordsToDelete );
            VSIUnlink( CPLResetExtension( oTempFile, "shp" ) );
            VSIUnlink( CPLResetExtension( oTempFile, "shx" ) );
            SHPClose( hNewSHP );
            return eErr;
        }

/* -------------------------------------------------------------------- */
/*      Cleanup the old .shp/.shx and rename the new one.               */
/* -------------------------------------------------------------------- */
        SHPClose( hSHP );
        SHPClose( hNewSHP );
        hSHP = hNewSHP = NULL;

        VSIUnlink( osSHPName );
        VSIUnlink( osSHXName );

        oTempFile = CPLResetExtension( oTempFile, "shp" );
        if( VSIRename( oTempFile, osSHPName ) != 0 )
        {
            CPLDebug( "Shape", "Can not rename SHP file: %s",
                      VSIStrerror( errno ) );
            CPLFree( panRecordsToDelete );
            return OGRERR_FAILURE;
        }

        oTempFile = CPLResetExtension( oTempFile, "shx" );
        if( VSIRename( oTempFile, osSHXName ) != 0 )
        {
            CPLDebug( "Shape", "Can not rename SHX file: %s",
                      VSIStrerror( errno ) );
            CPLFree( panRecordsToDelete );
            return OGRERR_FAILURE;
        }
    }

    CPLFree( panRecordsToDelete );
    panRecordsToDelete = NULL;

/* -------------------------------------------------------------------- */
/*      Reopen the shapefile                                            */
/*                                                                      */
/* We do not need to reimplement OGRShapeDataSource::OpenFile() here    */
/* with the fully featured error checking.                              */
/* If all operations above succeeded, then all necessary files are      */
/* in the right place and accessible.                                   */
/* -------------------------------------------------------------------- */

    const char* pszAccess = NULL;
    if( bUpdateAccess )
        pszAccess = "r+";
    else
        pszAccess = "r";

    if( bMustReopenSHP )
        hSHP = poDS->DS_SHPOpen ( osSHPName , pszAccess );
    if( bMustReopenDBF )
        hDBF = poDS->DS_DBFOpen ( osDBFName , pszAccess );

    if( (bMustReopenSHP && NULL == hSHP) || (bMustReopenDBF && NULL == hDBF) )
        return OGRERR_FAILURE;

/* -------------------------------------------------------------------- */
/*      Update total shape count.                                       */
/* -------------------------------------------------------------------- */
    if( hDBF != NULL )
        nTotalShapeCount = hDBF->nRecords;
    bSHPNeedsRepack = FALSE;

    return OGRERR_NONE;
}

/************************************************************************/
/*                               ResizeDBF()                            */
/*                                                                      */
/*      Autoshrink columns of the DBF file to their minimum             */
/*      size, according to the existing data.                           */
/************************************************************************/

OGRErr OGRShapeLayer::ResizeDBF()

{
    if (!TouchLayer())
        return OGRERR_FAILURE;

    if( !bUpdateAccess )
    {
        CPLError( CE_Failure, CPLE_NotSupported,
                  UNSUPPORTED_OP_READ_ONLY,
                  "ResizeDBF");
        return OGRERR_FAILURE;
    }

    if( hDBF == NULL )
    {
        CPLError( CE_Failure, CPLE_NotSupported,
                  "Attempt to RESIZE a shapefile with no .dbf file not supported.");
        return OGRERR_FAILURE;
    }

    int i, j;

    /* Look which columns must be examined */
    int* panColMap = (int*) CPLMalloc(poFeatureDefn->GetFieldCount() * sizeof(int));
    int* panBestWidth = (int*) CPLMalloc(poFeatureDefn->GetFieldCount() * sizeof(int));
    int nStringCols = 0;
    for( i = 0; i < poFeatureDefn->GetFieldCount(); i++ )
    {
        if( poFeatureDefn->GetFieldDefn(i)->GetType() == OFTString ||
            poFeatureDefn->GetFieldDefn(i)->GetType() == OFTInteger ||
            poFeatureDefn->GetFieldDefn(i)->GetType() == OFTInteger64 )
        {
            panColMap[nStringCols] = i;
            panBestWidth[nStringCols] = 1;
            nStringCols ++;
        }
    }

    if (nStringCols == 0)
    {
        /* Nothing to do */
        CPLFree(panColMap);
        CPLFree(panBestWidth);
        return OGRERR_NONE;
    }

    CPLDebug("SHAPE", "Computing optimal column size...");

    int bAlreadyWarned = FALSE;
    for( i = 0; i < hDBF->nRecords; i++ )
    {
        if( !DBFIsRecordDeleted( hDBF, i ) )
        {
            for( j = 0; j < nStringCols; j ++)
            {
                if (DBFIsAttributeNULL(hDBF, i, panColMap[j]))
                    continue;

                const char* pszVal = DBFReadStringAttribute(hDBF, i, panColMap[j]);
                int nLen =  static_cast<int>(strlen(pszVal));
                if (nLen > panBestWidth[j])
                    panBestWidth[j] = nLen;
            }
        }
        else if (!bAlreadyWarned)
        {
            bAlreadyWarned = TRUE;
            CPLDebug("SHAPE",
                     "DBF file would also need a REPACK due to deleted records");
        }
    }

    for( j = 0; j < nStringCols; j ++)
    {
        int             iField = panColMap[j];
        OGRFieldDefn*   poFieldDefn = poFeatureDefn->GetFieldDefn(iField);

        char            szFieldName[20];
        int             nOriWidth, nPrecision;
        char            chNativeType;
        /* DBFFieldType    eDBFType; */

        chNativeType = DBFGetNativeFieldType( hDBF, iField );
        /* eDBFType = */ DBFGetFieldInfo( hDBF, iField, szFieldName,
                                          &nOriWidth, &nPrecision );

        if (panBestWidth[j] < nOriWidth)
        {
            CPLDebug("SHAPE", "Shrinking field %d (%s) from %d to %d characters",
                        iField, poFieldDefn->GetNameRef(), nOriWidth, panBestWidth[j]);

            if (!DBFAlterFieldDefn( hDBF, iField, szFieldName,
                                    chNativeType, panBestWidth[j], nPrecision ))
            {
                CPLError(CE_Failure, CPLE_AppDefined,
                        "Shrinking field %d (%s) from %d to %d characters failed",
                        iField, poFieldDefn->GetNameRef(), nOriWidth, panBestWidth[j]);

                CPLFree(panColMap);
                CPLFree(panBestWidth);

                return OGRERR_FAILURE;
            }
            else
            {
                poFieldDefn->SetWidth(panBestWidth[j]);
            }
        }
    }

    TruncateDBF();

    CPLFree(panColMap);
    CPLFree(panBestWidth);

    return OGRERR_NONE;
}

/************************************************************************/
/*                          TruncateDBF()                               */
/************************************************************************/

void OGRShapeLayer::TruncateDBF()
{
    if (hDBF == NULL)
        return;

    hDBF->sHooks.FSeek(hDBF->fp, 0, SEEK_END);
    vsi_l_offset nOldSize = hDBF->sHooks.FTell(hDBF->fp);
    vsi_l_offset nNewSize = hDBF->nRecordLength * (SAOffset) hDBF->nRecords
                            + hDBF->nHeaderLength;
    if (nNewSize < nOldSize)
    {
        CPLDebug("SHAPE",
                 "Truncating DBF file from " CPL_FRMT_GUIB " to " CPL_FRMT_GUIB " bytes",
                 nOldSize, nNewSize);
        VSIFTruncateL(VSI_SHP_GetVSIL(hDBF->fp), nNewSize);
    }
    hDBF->sHooks.FSeek(hDBF->fp, 0, SEEK_SET);
}

/************************************************************************/
/*                        RecomputeExtent()                             */
/*                                                                      */
/*      Force recomputation of the extent of the .SHP file              */
/************************************************************************/

OGRErr OGRShapeLayer::RecomputeExtent()
{
    if (!TouchLayer())
        return OGRERR_FAILURE;

    if( !bUpdateAccess )
    {
        CPLError( CE_Failure, CPLE_NotSupported,
                  UNSUPPORTED_OP_READ_ONLY,
                  "RecomputeExtent");
        return OGRERR_FAILURE;
    }

    if( hSHP == NULL )
    {
        CPLError( CE_Failure, CPLE_AppDefined,
                  "The RECOMPUTE EXTENT operation is not permitted on a layer without .SHP file." );
        return OGRERR_FAILURE;
    }

    double adBoundsMin[4] = { 0.0, 0.0, 0.0, 0.0 };
    double adBoundsMax[4] = { 0.0, 0.0, 0.0, 0.0 };

    int bHasBeenInit = FALSE;

    for( int iShape = 0;
         iShape < nTotalShapeCount;
         iShape++ )
    {
        if( hDBF == NULL || !DBFIsRecordDeleted( hDBF, iShape ) )
        {
            SHPObject *psObject = SHPReadObject( hSHP, iShape );
            if ( psObject != NULL &&
                 psObject->nSHPType != SHPT_NULL &&
                 psObject->nVertices != 0 )
            {
                if( !bHasBeenInit )
                {
                    bHasBeenInit = TRUE;
                    adBoundsMin[0] = adBoundsMax[0] = psObject->padfX[0];
                    adBoundsMin[1] = adBoundsMax[1] = psObject->padfY[0];
                    if( psObject->padfZ )
                        adBoundsMin[2] = adBoundsMax[2] = psObject->padfZ[0];
                    if( psObject->padfM )
                        adBoundsMin[3] = adBoundsMax[3] = psObject->padfM[0];
                }

                for( int i = 0; i < psObject->nVertices; i++ )
                {
                    adBoundsMin[0] = MIN(adBoundsMin[0],psObject->padfX[i]);
                    adBoundsMin[1] = MIN(adBoundsMin[1],psObject->padfY[i]);
                    adBoundsMax[0] = MAX(adBoundsMax[0],psObject->padfX[i]);
                    adBoundsMax[1] = MAX(adBoundsMax[1],psObject->padfY[i]);
                    if( psObject->padfZ )
                    {
                        adBoundsMin[2] = MIN(adBoundsMin[2],psObject->padfZ[i]);
                        adBoundsMax[2] = MAX(adBoundsMax[2],psObject->padfZ[i]);
                    }
                    if( psObject->padfM )
                    {
                        adBoundsMax[3] = MAX(adBoundsMax[3],psObject->padfM[i]);
                        adBoundsMin[3] = MIN(adBoundsMin[3],psObject->padfM[i]);
                    }
                }
            }
            SHPDestroyObject(psObject);
        }
    }

    if( memcmp(hSHP->adBoundsMin, adBoundsMin, 4*sizeof(double)) != 0 ||
        memcmp(hSHP->adBoundsMax, adBoundsMax, 4*sizeof(double)) != 0 )
    {
        bHeaderDirty = TRUE;
        hSHP->bUpdated = TRUE;
        memcpy(hSHP->adBoundsMin, adBoundsMin, 4*sizeof(double));
        memcpy(hSHP->adBoundsMax, adBoundsMax, 4*sizeof(double));
    }

    return OGRERR_NONE;
}


/************************************************************************/
/*                              TouchLayer()                            */
/************************************************************************/

int OGRShapeLayer::TouchLayer()
{
    poDS->SetLastUsedLayer(this);

    if (eFileDescriptorsState == FD_OPENED)
        return TRUE;
    else if (eFileDescriptorsState == FD_CANNOT_REOPEN)
        return FALSE;
    else
        return ReopenFileDescriptors();
}

/************************************************************************/
/*                        ReopenFileDescriptors()                       */
/************************************************************************/

int OGRShapeLayer::ReopenFileDescriptors()
{
    CPLDebug("SHAPE", "ReopenFileDescriptors(%s)", pszFullName);

    if( bHSHPWasNonNULL )
    {
        if( bUpdateAccess )
            hSHP = poDS->DS_SHPOpen( pszFullName, "r+" );
        else
            hSHP = poDS->DS_SHPOpen( pszFullName, "r" );

        if (hSHP == NULL)
        {
            eFileDescriptorsState = FD_CANNOT_REOPEN;
            return FALSE;
        }
    }

    if( bHDBFWasNonNULL )
    {
        if( bUpdateAccess )
            hDBF = poDS->DS_DBFOpen( pszFullName, "r+" );
        else
            hDBF = poDS->DS_DBFOpen( pszFullName, "r" );

        if (hDBF == NULL)
        {
            CPLError(CE_Failure, CPLE_OpenFailed,
                     "Cannot reopen %s", CPLResetExtension(pszFullName, "dbf"));
            eFileDescriptorsState = FD_CANNOT_REOPEN;
            return FALSE;
        }
    }

    eFileDescriptorsState = FD_OPENED;

    return TRUE;
}

/************************************************************************/
/*                        CloseUnderlyingLayer()                        */
/************************************************************************/

void OGRShapeLayer::CloseUnderlyingLayer()
{
    CPLDebug("SHAPE", "CloseUnderlyingLayer(%s)", pszFullName);

    if( hDBF != NULL )
        DBFClose( hDBF );
    hDBF = NULL;

    if( hSHP != NULL )
        SHPClose( hSHP );
    hSHP = NULL;

    /* We close QIX and reset the check flag, so that CheckForQIX() */
    /* will retry opening it if necessary when the layer is active again */
    if( hQIX != NULL )
        SHPCloseDiskTree( hQIX );
    hQIX = NULL;
    bCheckedForQIX = FALSE;

    if( hSBN != NULL )
        SBNCloseDiskTree( hSBN );
    hSBN = NULL;
    bCheckedForSBN = FALSE;

    eFileDescriptorsState = FD_CLOSED;
}

/************************************************************************/
/*                            AddToFileList()                           */
/************************************************************************/

void OGRShapeLayer::AddToFileList( CPLStringList& oFileList )
{
    if (!TouchLayer())
        return;
    if( hSHP )
    {
        const char* pszSHPFilename = VSI_SHP_GetFilename( hSHP->fpSHP );
        oFileList.AddString(pszSHPFilename);
        const char* pszSHPExt = CPLGetExtension(pszSHPFilename);
        const char* pszSHXFilename = CPLResetExtension( pszSHPFilename,
                                        (pszSHPExt[0] == 's') ? "shx" : "SHX" );
        oFileList.AddString(pszSHXFilename);
    }
    if( hDBF )
    {
        const char* pszDBFFilename = VSI_SHP_GetFilename( hDBF->fp );
        oFileList.AddString(pszDBFFilename);
        if( hDBF->pszCodePage != NULL && hDBF->iLanguageDriver == 0 )
        {
            const char* pszDBFExt = CPLGetExtension(pszDBFFilename);
            const char* pszCPGFilename = CPLResetExtension( pszDBFFilename,
                                       (pszDBFExt[0] == 'd') ? "cpg" : "CPG"  );
            oFileList.AddString(pszCPGFilename);
        }
    }
    if( hSHP )
    {
        if( GetSpatialRef() != NULL )
        {
            OGRShapeGeomFieldDefn* poGeomFieldDefn =
                (OGRShapeGeomFieldDefn*)GetLayerDefn()->GetGeomFieldDefn(0);
            oFileList.AddString(poGeomFieldDefn->GetPrjFilename());
        }
        if( CheckForQIX() )
        {
            const char* pszQIXFilename = CPLResetExtension( pszFullName, "qix" );
            oFileList.AddString(pszQIXFilename);
        }
        else if( CheckForSBN() )
        {
            const char* pszSBNFilename = CPLResetExtension( pszFullName, "sbn" );
            oFileList.AddString(pszSBNFilename);
            const char* pszSBXFilename = CPLResetExtension( pszFullName, "sbx" );
            oFileList.AddString(pszSBXFilename);
        }
    }
}
