ogrfeature.cpp

用于读取TAB、MIF、SHP文件的类

/************************************************************************/
/*                        OGR_F_GetRawFieldRef()                        */
/************************************************************************/

/**
 * Fetch an handle to the internal field value given the index.  
 *
 * This function is the same as the C++ method OGRFeature::GetRawFieldRef().
 *
 * @param hFeat handle to the feature on which field is found.
 * @param iField the field to fetch, from 0 to GetFieldCount()-1.
 *
 * @return the returned handle is to an internal data structure, and should
 * not be freed, or modified. 
 */

OGRField *OGR_F_GetRawFieldRef( OGRFeatureH hFeat, int iField )

{
    return ((OGRFeature *)hFeat)->GetRawFieldRef( iField );
}

/************************************************************************/
/*                         GetFieldAsInteger()                          */
/************************************************************************/

/**
 * Fetch field value as integer.
 *
 * OFTString features will be translated using atoi().  OFTReal fields
 * will be cast to integer.   Other field types, or errors will result in
 * a return value of zero.
 *
 * This method is the same as the C function OGR_F_GetFieldAsInteger().
 *
 * @param iField the field to fetch, from 0 to GetFieldCount()-1.
 *
 * @return the field value.
 */

int OGRFeature::GetFieldAsInteger( int iField )

{
    int iSpecialField = iField - poDefn->GetFieldCount();
    if (iSpecialField >= 0)
    {
    // special field value accessors
        switch (iSpecialField)
        {
        case SPF_FID:
            return GetFID();
        default:
            return 0;
        }
    }
    
    OGRFieldDefn        *poFDefn = poDefn->GetFieldDefn( iField );
    
    CPLAssert( poFDefn != NULL || iField == -1 );
    if( poFDefn == NULL )
        return 0;
    
    if( !IsFieldSet(iField) )
        return 0;
    
    if( poFDefn->GetType() == OFTInteger )
        return pauFields[iField].Integer;
    else if( poFDefn->GetType() == OFTReal )
        return (int) pauFields[iField].Real;
    else if( poFDefn->GetType() == OFTString )
    {
        if( pauFields[iField].String == NULL )
            return 0;
        else
            return atoi(pauFields[iField].String);
    }
    else
        return 0;
}

/************************************************************************/
/*                      OGR_F_GetFieldAsInteger()                       */
/************************************************************************/

/**
 * Fetch field value as integer.
 *
 * OFTString features will be translated using atoi().  OFTReal fields
 * will be cast to integer.   Other field types, or errors will result in
 * a return value of zero.
 *
 * This function is the same as the C++ method OGRFeature::GetFieldAsInteger().
 *
 * @param hFeat handle to the feature that owned the field.
 * @param iField the field to fetch, from 0 to GetFieldCount()-1.
 *
 * @return the field value.
 */

int OGR_F_GetFieldAsInteger( OGRFeatureH hFeat, int iField )

{
    return ((OGRFeature *)hFeat)->GetFieldAsInteger(iField);
}

/************************************************************************/
/*                          GetFieldAsDouble()                          */
/************************************************************************/

/**
 * Fetch field value as a double.
 *
 * OFTString features will be translated using atof().  OFTInteger fields
 * will be cast to double.   Other field types, or errors will result in
 * a return value of zero.
 *
 * This method is the same as the C function OGR_F_GetFieldAsDouble().
 *
 * @param iField the field to fetch, from 0 to GetFieldCount()-1.
 *
 * @return the field value.
 */

double OGRFeature::GetFieldAsDouble( int iField )

{
    int iSpecialField = iField - poDefn->GetFieldCount();
    if (iSpecialField >= 0)
    {
    // special field value accessors
        switch (iSpecialField)
        {
        case SPF_FID:
            return GetFID();
        default:
            return 0.0;
        }
    }
    
    OGRFieldDefn        *poFDefn = poDefn->GetFieldDefn( iField );
    
    CPLAssert( poFDefn != NULL || iField == -1 );
    if( poFDefn == NULL )
        return 0.0;

    if( !IsFieldSet(iField) )
        return 0.0;
    
    if( poFDefn->GetType() == OFTReal )
        return pauFields[iField].Real;
    else if( poFDefn->GetType() == OFTInteger )
        return pauFields[iField].Integer;
    else if( poFDefn->GetType() == OFTString )
    {
        if( pauFields[iField].String == NULL )
            return 0;
        else
            return atof(pauFields[iField].String);
    }
    else
        return 0.0;
}

/************************************************************************/
/*                       OGR_F_GetFieldAsDouble()                       */
/************************************************************************/

/**
 * Fetch field value as a double.
 *
 * OFTString features will be translated using atof().  OFTInteger fields
 * will be cast to double.   Other field types, or errors will result in
 * a return value of zero.
 *
 * This function is the same as the C++ method OGRFeature::GetFieldAsDouble().
 *
 * @param hFeat handle to the feature that owned the field.
 * @param iField the field to fetch, from 0 to GetFieldCount()-1.
 *
 * @return the field value.
 */

double OGR_F_GetFieldAsDouble( OGRFeatureH hFeat, int iField )

{
    return ((OGRFeature *)hFeat)->GetFieldAsDouble(iField);
}

/************************************************************************/
/*                          GetFieldAsString()                          */
/************************************************************************/

/**
 * Fetch field value as a string.
 *
 * OFTReal and OFTInteger fields will be translated to string using
 * sprintf(), but not necessarily using the established formatting rules.
 * Other field types, or errors will result in a return value of zero.
 *
 * This method is the same as the C function OGR_F_GetFieldAsString().
 *
 * @param iField the field to fetch, from 0 to GetFieldCount()-1.
 *
 * @return the field value.  This string is internal, and should not be
 * modified, or freed.  It's lifetime may be very brief. 
 */

const char *OGRFeature::GetFieldAsString( int iField )

{
#define TEMP_BUFFER_SIZE 80
    char         szTempBuffer[TEMP_BUFFER_SIZE];

    CPLFree(m_pszTmpFieldValue);
    m_pszTmpFieldValue = NULL;            

    int iSpecialField = iField - poDefn->GetFieldCount();
    if (iSpecialField >= 0)
    {
    // special field value accessors
        switch (iSpecialField)
        {
        case SPF_FID:
            snprintf( szTempBuffer, TEMP_BUFFER_SIZE, "%ld", GetFID() );
            return m_pszTmpFieldValue = CPLStrdup( szTempBuffer );
        case SPF_OGR_GEOMETRY:
            return poGeometry->getGeometryName();
        case SPF_OGR_STYLE:
            return GetStyleString();
        case SPF_OGR_GEOM_WKT:
            {
                if (poGeometry->exportToWkt( &m_pszTmpFieldValue ) == OGRERR_NONE )
                    return m_pszTmpFieldValue;
                else
                    return "";
            }
        default:
            return "";
        }
    }
    
    OGRFieldDefn        *poFDefn = poDefn->GetFieldDefn( iField );
    
    CPLAssert( poFDefn != NULL || iField == -1 );
    if( poFDefn == NULL )
        return "";
    
    if( !IsFieldSet(iField) )
        return "";
    
    if( poFDefn->GetType() == OFTString )
    {
        if( pauFields[iField].String == NULL )
            return "";
        else
            return pauFields[iField].String;
    }
    else if( poFDefn->GetType() == OFTInteger )
    {
        snprintf( szTempBuffer, TEMP_BUFFER_SIZE,
                  "%d", pauFields[iField].Integer );
        return m_pszTmpFieldValue = CPLStrdup( szTempBuffer );
    }
    else if( poFDefn->GetType() == OFTReal )
    {
        char    szFormat[64];

        if( poFDefn->GetWidth() != 0 )
        {
            snprintf( szFormat, TEMP_BUFFER_SIZE, "%%%d.%df",
                     poFDefn->GetWidth(), poFDefn->GetPrecision() );
        }
        else
            strcpy( szFormat, "%.15g" );
        
        snprintf( szTempBuffer, TEMP_BUFFER_SIZE,
                  szFormat, pauFields[iField].Real );
        
        return m_pszTmpFieldValue = CPLStrdup( szTempBuffer );
    }
    else if( poFDefn->GetType() == OFTDateTime )
    {
        snprintf( szTempBuffer, TEMP_BUFFER_SIZE,
                  "%04d/%02d/%02d %2d:%02d:%02d", 
                  pauFields[iField].Date.Year,
                  pauFields[iField].Date.Month,
                  pauFields[iField].Date.Day,
                  pauFields[iField].Date.Hour,
                  pauFields[iField].Date.Minute,
                  pauFields[iField].Date.Second );
        
        if( pauFields[iField].Date.TZFlag > 1 )
        {
            int nOffset = (pauFields[iField].Date.TZFlag - 100) * 15;
            int nHours = (int) (nOffset / 60);  // round towards zero
            int nMinutes = ABS(nOffset - nHours * 60);

            if( nOffset < 0 )
            {
                strcat( szTempBuffer, "-" );
                nHours = ABS(nHours);
            }
            else
                strcat( szTempBuffer, "+" );

            if( nMinutes == 0 )
                snprintf( szTempBuffer+strlen(szTempBuffer), 
                         TEMP_BUFFER_SIZE, "%02d", nHours );
            else
                snprintf( szTempBuffer+strlen(szTempBuffer), 
                         TEMP_BUFFER_SIZE, "%02d%02d", nHours, nMinutes );
        }

        return m_pszTmpFieldValue = CPLStrdup( szTempBuffer );
    }
    else if( poFDefn->GetType() == OFTDate )
    {
        snprintf( szTempBuffer, TEMP_BUFFER_SIZE, "%04d/%02d/%02d",
                 pauFields[iField].Date.Year,
                 pauFields[iField].Date.Month,
                 pauFields[iField].Date.Day );

        return m_pszTmpFieldValue = CPLStrdup( szTempBuffer );
    }
    else if( poFDefn->GetType() == OFTTime )
    {
        snprintf( szTempBuffer, TEMP_BUFFER_SIZE, "%2d:%02d:%02d", 
                 pauFields[iField].Date.Hour,
                 pauFields[iField].Date.Minute,
                 pauFields[iField].Date.Second );
        
        return m_pszTmpFieldValue = CPLStrdup( szTempBuffer );
    }
    else if( poFDefn->GetType() == OFTIntegerList )
    {
        char    szItem[32];
        int     i, nCount = pauFields[iField].IntegerList.nCount;

        snprintf( szTempBuffer, TEMP_BUFFER_SIZE, "(%d:", nCount );
        for( i = 0; i < nCount; i++ )
        {
            snprintf( szItem, TEMP_BUFFER_SIZE, "%d",
                      pauFields[iField].IntegerList.paList[i] );
            if( strlen(szTempBuffer) + strlen(szItem) + 6
                > sizeof(szTempBuffer) )
            {
                break;
            }
            
            if( i > 0 )
                strcat( szTempBuffer, "," );
            
            strcat( szTempBuffer, szItem );
        }

        if( i < nCount )
            strcat( szTempBuffer, ",...)" );
        else
            strcat( szTempBuffer, ")" );
        
        return m_pszTmpFieldValue = CPLStrdup( szTempBuffer );
    }
    else if( poFDefn->GetType() == OFTRealList )
    {
        char    szItem[40];
        char    szFormat[64];
        int     i, nCount = pauFields[iField].RealList.nCount;

        if( poFDefn->GetWidth() != 0 )
        {
            snprintf( szFormat, TEMP_BUFFER_SIZE, "%%%d.%df",
                      poFDefn->GetWidth(), poFDefn->GetPrecision() );
        }
        else
            strcpy( szFormat, "%.16g" );
        
        snprintf( szTempBuffer, TEMP_BUFFER_SIZE, "(%d:", nCount );
        for( i = 0; i < nCount; i++ )
        {
            snprintf( szItem, TEMP_BUFFER_SIZE, szFormat,
                      pauFields[iField].RealList.paList[i] );
            if( strlen(szTempBuffer) + strlen(szItem) + 6
                > sizeof(szTempBuffer) )
            {
                break;
            }
            
            if( i > 0 )
                strcat( szTempBuffer, "," );
            
            strcat( szTempBuffer, szItem );
        }

        if( i < nCount )
            strcat( szTempBuffer, ",...)" );
        else
            strcat( szTempBuffer, ")" );
        
        return m_pszTmpFieldValue = CPLStrdup( szTempBuffer );
    }
    else if( poFDefn->GetType() == OFTStringList )
    {
        int     i, nCount = pauFields[iField].StringList.nCount;

        snprintf( szTempBuffer, TEMP_BUFFER_SIZE, "(%d:", nCount );
        for( i = 0; i < nCount; i++ )
        {
            const char  *pszItem = pauFields[iField].StringList.paList[i];