src/kits/support/DataPositionIOWrapper.cpp

   1 /*
   2  * Copyright 2014, Ingo Weinhold, ingo_weinhold@gmx.de.
   3  * Distributed under the terms of the MIT License.
   4  */
   5
   6
   7 #include <DataPositionIOWrapper.h>
   8
   9 #include <stdio.h>
  10
  11
  12 BDataPositionIOWrapper::BDataPositionIOWrapper(BDataIO* io)
  13         :
  14         BPositionIO(),
  15         fIO(io),
  16         fPosition(0)
  17 {
  18 }
  19
  20
  21 BDataPositionIOWrapper::~BDataPositionIOWrapper()
  22 {
  23 }
  24
  25
  26 ssize_t
  27 BDataPositionIOWrapper::Read(void* buffer, size_t size)
  28 {
  29         ssize_t bytesRead = fIO->Read(buffer, size);
  30         if (bytesRead > 0)
  31                 fPosition += bytesRead;
  32
  33         return bytesRead;
  34 }
  35
  36
  37 ssize_t
  38 BDataPositionIOWrapper::Write(const void* buffer, size_t size)
  39 {
  40         ssize_t bytesWritten = fIO->Write(buffer, size);
  41         if (bytesWritten > 0)
  42                 fPosition += bytesWritten;
  43
  44         return bytesWritten;
  45 }
  46
  47
  48 ssize_t
  49 BDataPositionIOWrapper::ReadAt(off_t position, void* buffer, size_t size)
  50 {
  51         if (position != fPosition)
  52                 return B_NOT_SUPPORTED;
  53
  54         return Read(buffer, size);
  55 }
  56
  57
  58 ssize_t
  59 BDataPositionIOWrapper::WriteAt(off_t position, const void* buffer,
  60         size_t size)
  61 {
  62         if (position != fPosition)
  63                 return B_NOT_SUPPORTED;
  64
  65         return Write(buffer, size);
  66 }
  67
  68
  69 off_t
  70 BDataPositionIOWrapper::Seek(off_t position, uint32 seekMode)
  71 {
  72         switch (seekMode) {
  73                 case SEEK_CUR:
  74                         return position == 0 ? B_OK : B_NOT_SUPPORTED;
  75                 case SEEK_SET:
  76                         return position == fPosition ? B_OK : B_NOT_SUPPORTED;
  77                 case SEEK_END:
  78                         return B_NOT_SUPPORTED;
  79                 default:
  80                         return B_BAD_VALUE;
  81         }
  82 }
  83
  84
  85 off_t
  86 BDataPositionIOWrapper::Position() const
  87 {
  88         return fPosition;
  89 }
  90
  91
  92 status_t
  93 BDataPositionIOWrapper::SetSize(off_t size)
  94 {
  95         return size == fPosition ? B_OK : B_NOT_SUPPORTED;
  96 }
  97
  98
  99 status_t
 100 BDataPositionIOWrapper::GetSize(off_t* size) const
 101 {
 102         return B_NOT_SUPPORTED;
 103 }