ddfsubfielddefn.cpp

国际海图标准S-57格式数据读取源码VC

/************************************************************************/
/*                           ExtractIntData()                           */
/************************************************************************/

/**
 * Extract a subfield value as an integer.  Given a pointer to the data
 * for this subfield (from within a DDFRecord) this method will return the
 * int data for this subfield.  The number of bytes
 * consumed as part of this field can also be fetched.  This method may be
 * called for any type of subfield, and will return zero if the subfield is
 * not numeric.
 *
 * @param pachSourceData The pointer to the raw data for this field.  This
 * may have come from DDFRecord::GetData(), taking into account skip factors
 * over previous subfields data.
 * @param nMaxBytes The maximum number of bytes that are accessable after
 * pachSourceData.
 * @param pnConsumedBytes Pointer to an integer into which the number of
 * bytes consumed by this field should be written.  May be NULL to ignore.
 * This is used as a skip factor to increment pachSourceData to point to the
 * next subfields data.
 *
 * @return The subfield's numeric value (or zero if it isn't numeric).
 *
 * @see ExtractFloatData(), ExtractStringData()
 */

int
DDFSubfieldDefn::ExtractIntData( const char * pachSourceData,
                                 int nMaxBytes, int * pnConsumedBytes )

{
    switch( pszFormatString[0] )
    {
      case 'A':
      case 'I':
      case 'R':
      case 'S':
      case 'C':
        return atoi(ExtractStringData(pachSourceData, nMaxBytes,
                                      pnConsumedBytes));

      case 'B':
      case 'b':
      {
          unsigned char   abyData[8];

          if( nFormatWidth > nMaxBytes )
          {
              CPLError( CE_Warning, CPLE_AppDefined, 
                        "Attempt to extract int subfield %s with format %s\n"
                        "failed as only %d bytes available.  Using zero.",
                        pszName, pszFormatString, nMaxBytes );
              return 0;
          }

          if( pnConsumedBytes != NULL )
              *pnConsumedBytes = nFormatWidth;

          // Byte swap the data if it isn't in machine native format.
          // In any event we copy it into our buffer to ensure it is
          // word aligned.
#ifdef CPL_LSB
          if( pszFormatString[0] == 'B' )
#else            
              if( pszFormatString[0] == 'b' )
#endif            
              {
                  for( int i = 0; i < nFormatWidth; i++ )
                      abyData[nFormatWidth-i-1] = pachSourceData[i];
              }
              else
              {
                  memcpy( abyData, pachSourceData, nFormatWidth );
              }

          // Interpret the bytes of data.
          switch( eBinaryFormat )
          {
            case UInt:
              if( nFormatWidth == 4 )
                  return( (int) *((GUInt32 *) abyData) );
              else if( nFormatWidth == 1 )
                  return( abyData[0] );
              else if( nFormatWidth == 2 )
                  return( *((GUInt16 *) abyData) );
              else
              {
                  CPLAssert( FALSE );
                  return 0;
              }
            
            case SInt:
              if( nFormatWidth == 4 )
                  return( *((GInt32 *) abyData) );
              else if( nFormatWidth == 1 )
                  return( *((signed char *) abyData) );
              else if( nFormatWidth == 2 )
                  return( *((GInt16 *) abyData) );
              else
              {
                  CPLAssert( FALSE );
                  return 0;
              }
            
            case FloatReal:
              if( nFormatWidth == 4 )
                  return( (int) *((float *) abyData) );
              else if( nFormatWidth == 8 )
                  return( (int) *((double *) abyData) );
              else
              {
                  CPLAssert( FALSE );
                  return 0;
              }

            case NotBinary:            
            case FPReal:
            case FloatComplex:
              CPLAssert( FALSE );
              return 0;
          }
          break;
          // end of 'b'/'B' case.
      }

      default:
        CPLAssert( FALSE );
        return 0;
    }

    CPLAssert( FALSE );
    return 0;
}

/************************************************************************/
/*                              DumpData()                              */
/*                                                                      */
/*      Dump the instance data for this subfield from a data            */
/*      record.  This fits into the output dump stream of a DDFField.   */
/************************************************************************/

/**
 * Dump subfield value to debugging file.
 *
 * @param pachData Pointer to data for this subfield.
 * @param nMaxBytes Maximum number of bytes available in pachData.
 * @param fp File to write report to.
 */

void DDFSubfieldDefn::DumpData( const char * pachData, int nMaxBytes,
                                FILE * fp )

{
    if( eType == DDFFloat )
        fprintf( fp, "      Subfield `%s' = %f\n",
                 pszName,
                 ExtractFloatData( pachData, nMaxBytes, NULL ) );
    else if( eType == DDFInt )
        fprintf( fp, "      Subfield `%s' = %d\n",
                 pszName,
                 ExtractIntData( pachData, nMaxBytes, NULL ) );
    else if( eType == DDFBinaryString )
    {
        int     nBytes, i;
        GByte   *pabyBString = (GByte *) ExtractStringData( pachData, nMaxBytes, &nBytes );

        fprintf( fp, "      Subfield `%s' = 0x", pszName );
        for( i = 0; i < MIN(nBytes,24); i++ )
            fprintf( fp, "%02X", pabyBString[i] );

        if( nBytes > 24 )
            fprintf( fp, "%s", "..." );

        fprintf( fp, "\n" );
    }
    else
        fprintf( fp, "      Subfield `%s' = `%s'\n",
                 pszName,
                 ExtractStringData( pachData, nMaxBytes, NULL ) );
}

/************************************************************************/
/*                          GetDefaultValue()                           */
/************************************************************************/

/**
 * Get default data. 
 *
 * Returns the default subfield data contents for this subfield definition.
 * For variable length numbers this will normally be "0<unit-terminator>". 
 * For variable length strings it will be "<unit-terminator>".  For fixed
 * length numbers it is zero filled.  For fixed length strings it is space
 * filled.  For binary numbers it is binary zero filled. 
 *
 * @param pachData the buffer into which the returned default will be placed.
 * May be NULL if just querying default size.
 * @param nBytesAvailable the size of pachData in bytes. 
 * @param pnBytesUsed will receive the size of the subfield default data in
 * bytes.
 *
 * @return TRUE on success or FALSE on failure or if the passed buffer is too
 * small to hold the default.
 */

int DDFSubfieldDefn::GetDefaultValue( char *pachData, int nBytesAvailable, 
                                      int *pnBytesUsed )

{
    int nDefaultSize;

    if( !bIsVariable )
        nDefaultSize = nFormatWidth;
    else
        nDefaultSize = 1;

    if( pnBytesUsed != NULL )
        *pnBytesUsed = nDefaultSize;

    if( pachData == NULL )
        return TRUE;

    if( nBytesAvailable < nDefaultSize )
        return FALSE;

    if( bIsVariable )
    {
        pachData[0] = DDF_UNIT_TERMINATOR;
    }
    else
    {
        if( GetBinaryFormat() == NotBinary )
        {
            if( GetType() == DDFInt || GetType() == DDFFloat )
                memset( pachData, '0', nDefaultSize );
            else
                memset( pachData, ' ', nDefaultSize );
        }
        else
            memset( pachData, 0, nDefaultSize );
    }

    return TRUE;
}

/************************************************************************/
/*                         FormatStringValue()                          */
/************************************************************************/

/**
 * Format string subfield value.
 *
 * Returns a buffer with the passed in string value reformatted in a way
 * suitable for storage in a DDFField for this subfield.  
 */

int DDFSubfieldDefn::FormatStringValue( char *pachData, int nBytesAvailable, 
                                        int *pnBytesUsed, 
                                        const char *pszValue,
                                        int nValueLength )

{
    int nSize;

    if( nValueLength == -1 )
        nValueLength = strlen(pszValue);

    if( bIsVariable )
    {
        nSize = nValueLength + 1;
    }
    else
    {                                                                  
        nSize = nFormatWidth;
    }

    if( pnBytesUsed != NULL )
        *pnBytesUsed = nSize;

    if( pachData == NULL )
        return TRUE;

    if( nBytesAvailable < nSize )
        return FALSE;

    if( bIsVariable )
    {
        strncpy( pachData, pszValue, nSize-1 );
        pachData[nSize-1] = DDF_UNIT_TERMINATOR;
    }
    else
    {
        if( GetBinaryFormat() == NotBinary )
        {
            memset( pachData, ' ', nSize );
            memcpy( pachData, pszValue, MIN(nValueLength,nSize) );
        }
        else
        {
            memset( pachData, 0, nSize );
            memcpy( pachData, pszValue, MIN(nValueLength,nSize) );
        }
    }

    return TRUE;
}

/************************************************************************/
/*                           FormatIntValue()                           */
/************************************************************************/

/**
 * Format int subfield value.
 *
 * Returns a buffer with the passed in int value reformatted in a way
 * suitable for storage in a DDFField for this subfield.  
 */

int DDFSubfieldDefn::FormatIntValue( char *pachData, int nBytesAvailable, 
                                     int *pnBytesUsed, int nNewValue )

{
    int nSize;
    char szWork[30];

    sprintf( szWork, "%d", nNewValue );

    if( bIsVariable )
    {
        nSize = strlen(szWork) + 1;
    }
    else
    {                                                                  
        nSize = nFormatWidth;

        if( GetBinaryFormat() == NotBinary && (int) strlen(szWork) > nSize )
            return FALSE;
    }

    if( pnBytesUsed != NULL )
        *pnBytesUsed = nSize;

    if( pachData == NULL )
        return TRUE;

    if( nBytesAvailable < nSize )
        return FALSE;

    if( bIsVariable )
    {
        strncpy( pachData, szWork, nSize-1 );
        pachData[nSize-1] = DDF_UNIT_TERMINATOR;
    }
    else
    {
        GUInt32 nMask = 0xff;
        int i;

        switch( GetBinaryFormat() )
        {
          case NotBinary:
            memset( pachData, '0', nSize );
            strncpy( pachData + nSize - strlen(szWork), szWork,
                     strlen(szWork) );
            break;

          case UInt:
          case SInt:
            for( i = 0; i < nFormatWidth; i++ )
            {
                int iOut;

                // big endian required?
                if( pszFormatString[0] == 'B' )
                    iOut = nFormatWidth - i - 1;
                else
                    iOut = i;

                pachData[iOut] = (nNewValue & nMask) >> (i*8);
                nMask *= 256;
            }
            break;

          case FloatReal:
            CPLAssert( FALSE );
            break;

          default:
            CPLAssert( FALSE );
            break;
        }
    }

    return TRUE;
}

/************************************************************************/
/*                          FormatFloatValue()                          */
/************************************************************************/

/**
 * Format float subfield value.
 *
 * Returns a buffer with the passed in float value reformatted in a way
 * suitable for storage in a DDFField for this subfield.  
 */

int DDFSubfieldDefn::FormatFloatValue( char *pachData, int nBytesAvailable, 
                                       int *pnBytesUsed, double dfNewValue )

{
    int nSize;
    char szWork[120];

    sprintf( szWork, "%.16g", dfNewValue );

    if( bIsVariable )
    {
        nSize = strlen(szWork) + 1;
    }
    else
    {
        nSize = nFormatWidth;

        if( GetBinaryFormat() == NotBinary && (int) strlen(szWork) > nSize )
            return FALSE;
    }

    if( pnBytesUsed != NULL )
        *pnBytesUsed = nSize;

    if( pachData == NULL )
        return TRUE;

    if( nBytesAvailable < nSize )
        return FALSE;

    if( bIsVariable )
    {
        strncpy( pachData, szWork, nSize-1 );
        pachData[nSize-1] = DDF_UNIT_TERMINATOR;
    }
    else
    {
        if( GetBinaryFormat() == NotBinary )
        {
            memset( pachData, '0', nSize );
            strncpy( pachData + nSize - strlen(szWork), szWork,
                     strlen(szWork) );
        }
        else
        {
            CPLAssert( FALSE );
            /* implement me */
        }
    }

    return TRUE;
}