src/bin/makeudfimage/EmbeddedStream.cpp

   1 //----------------------------------------------------------------------
   2 //  This software is part of the OpenBeOS distribution and is covered
   3 //  by the MIT License.
   4 //
   5 //  Copyright (c) 2003 Tyler Dauwalder, tyler@dauwalder.net
   6 //----------------------------------------------------------------------
   7
   8 /*! \file EmbeddedStream.cpp
   9 */
  10
  11 #include "EmbeddedStream.h"
  12
  13 #include <stdlib.h>
  14 #include <string.h>
  15
  16 EmbeddedStream::EmbeddedStream(DataStream &stream, off_t offset, size_t size)
  17         : SimulatedStream(stream)
  18         , fOffset(offset)
  19         , fSize(size)
  20 {
  21 }
  22
  23 /*! \brief Returns the largest extent in the underlying data stream
  24         corresponding to the extent starting at byte position \a pos of
  25         byte length \a size in the output parameter \a extent.
  26
  27         NOTE: If the position is at or beyond the end of the stream, the
  28         function will return B_OK, but the value of extent.size will be 0.
  29 */
  30 status_t
  31 EmbeddedStream::_GetExtent(off_t pos, size_t size, data_extent &extent)
  32 {
  33         if (pos >= fSize) {
  34                 // end of stream
  35                 extent.offset = fOffset + fSize;
  36                 extent.size = 0;
  37         } else {
  38                 // valid position
  39                 extent.offset = fOffset + pos;
  40                 extent.size = fSize - pos;
  41         }
  42         return B_OK;
  43 }
  44
  45 /*! \brief Returns the current size of the stream.
  46 */
  47 off_t
  48 EmbeddedStream::_Size()
  49 {
  50         return fSize;
  51 }