ddfsubfielddefn.cpp

开源的电子海图程序

        if( pnConsumedBytes != NULL )
        {
            if( nMaxBytes == 0 )
                *pnConsumedBytes = nLength;
            else
                *pnConsumedBytes = nLength+1;
        }
        
        return nLength;
    }
}

/************************************************************************/
/*                         ExtractStringData()                          */
/************************************************************************/

/**
 * Extract a zero terminated string containing the data for this subfield.
 * Given a pointer to the data
 * for this subfield (from within a DDFRecord) this method will return the
 * data for this subfield.  The number of bytes
 * consumed as part of this field can also be fetched.  This number may
 * be one longer than the string length if there is a terminator character
 * used.<p>
 *
 * This function will return the raw binary data of a subfield for
 * types other than DDFString, including data past zero chars.  This is
 * the standard way of extracting DDFBinaryString subfields for instance.<p>
 *
 * @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 A pointer to a buffer containing the data for this field.  The
 * returned pointer is to an internal buffer which is invalidated on the
 * next ExtractStringData() call on this DDFSubfieldDefn().  It should not
 * be freed by the application.
 *
 * @see ExtractIntData(), ExtractFloatData()
 */

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

{
    int         nLength = GetDataLength( pachSourceData, nMaxBytes,
                                         pnConsumedBytes );

/* -------------------------------------------------------------------- */
/*      Do we need to grow the buffer.                                  */
/* -------------------------------------------------------------------- */
    if( nMaxBufChars < nLength+1 )
    {
        CPLFree( pachBuffer );
        
        nMaxBufChars = nLength+1;
        pachBuffer = (char *) CPLMalloc(nMaxBufChars);
    }

/* -------------------------------------------------------------------- */
/*      Copy the data to the buffer.  We use memcpy() so that it        */
/*      will work for binary data.                                      */
/* -------------------------------------------------------------------- */
    memcpy( pachBuffer, pachSourceData, nLength );
    pachBuffer[nLength] = '\0';

    return pachBuffer;
}

/************************************************************************/
/*                          ExtractFloatData()                          */
/************************************************************************/

/**
 * Extract a subfield value as a float.  Given a pointer to the data
 * for this subfield (from within a DDFRecord) this method will return the
 * floating point 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 ExtractIntData(), ExtractStringData()
 */

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

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

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

          CPLAssert( nFormatWidth <= nMaxBytes );
          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 == 1 )
                  return( abyData[0] );
              else if( nFormatWidth == 2 )
                  return( *((GUInt16 *) abyData) );
              else if( nFormatWidth == 4 )
                  return( *((GUInt32 *) abyData) );
              else
              {
                  CPLAssert( FALSE );
                  return 0.0;
              }
            
            case SInt:
              if( nFormatWidth == 1 )
                  return( *((signed char *) abyData) );
              else if( nFormatWidth == 2 )
                  return( *((GInt16 *) abyData) );
              else if( nFormatWidth == 4 )
                  return( *((GInt32 *) abyData) );
              else
              {
                  CPLAssert( FALSE );
                  return 0.0;
              }
            
            case FloatReal:
              if( nFormatWidth == 4 )
                  return( *((float *) abyData) );
              else if( nFormatWidth == 8 )
                  return( *((double *) abyData) );
              else
              {
                  CPLAssert( FALSE );
                  return 0.0;
              }

            case NotBinary:            
            case FPReal:
            case FloatComplex:
              CPLAssert( FALSE );
              return 0.0;
          }
          break;
          // end of 'b'/'B' case.
      }

      default:
        CPLAssert( FALSE );
        return 0.0;
    }

    CPLAssert( FALSE );
    return 0.0;
}

/************************************************************************/
/*                           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;