src/kits/storage/FileIO.cpp

   1 /*
   2  * Copyright 2009-2010, Ingo Weinhold, ingo_weinhold@gmx.de.
   3  * Distributed under the terms of the MIT License.
   4  */
   5
   6
   7 #include <FileIO.h>
   8
   9 #include <errno.h>
  10 #include <stdio.h>
  11
  12
  13 BFileIO::BFileIO(FILE* file, bool takeOverOwnership)
  14         :
  15         fFile(file),
  16         fOwnsFile(takeOverOwnership)
  17 {
  18 }
  19
  20
  21 BFileIO::~BFileIO()
  22 {
  23         if (fOwnsFile && fFile != NULL)
  24                 fclose(fFile);
  25 }
  26
  27
  28 ssize_t
  29 BFileIO::Read(void* buffer, size_t size)
  30 {
  31         errno = B_OK;
  32         ssize_t bytesRead = fread(buffer, 1, size, fFile);
  33         return bytesRead >= 0 ? bytesRead : errno;
  34 }
  35
  36
  37 ssize_t
  38 BFileIO::Write(const void* buffer, size_t size)
  39 {
  40         errno = B_OK;
  41         ssize_t bytesRead = fwrite(buffer, 1, size, fFile);
  42         return bytesRead >= 0 ? bytesRead : errno;
  43 }
  44
  45
  46 ssize_t
  47 BFileIO::ReadAt(off_t position, void* buffer, size_t size)
  48 {
  49         // save the old position and seek to the requested one
  50         off_t oldPosition = _Seek(position, SEEK_SET);
  51         if (oldPosition < 0)
  52                 return oldPosition;
  53
  54         // read
  55         ssize_t result = BFileIO::Read(buffer, size);
  56
  57         // seek back
  58         fseeko(fFile, oldPosition, SEEK_SET);
  59
  60         return result;
  61 }
  62
  63
  64 ssize_t
  65 BFileIO::WriteAt(off_t position, const void* buffer, size_t size)
  66 {
  67         // save the old position and seek to the requested one
  68         off_t oldPosition = _Seek(position, SEEK_SET);
  69         if (oldPosition < 0)
  70                 return oldPosition;
  71
  72         // write
  73         ssize_t result = BFileIO::Write(buffer, size);
  74
  75         // seek back
  76         fseeko(fFile, oldPosition, SEEK_SET);
  77
  78         return result;
  79 }
  80
  81
  82 off_t
  83 BFileIO::Seek(off_t position, uint32 seekMode)
  84 {
  85         if (fseeko(fFile, position, seekMode) < 0)
  86                 return errno;
  87
  88         return BFileIO::Position();
  89 }
  90
  91
  92 off_t
  93 BFileIO::Position() const
  94 {
  95         off_t result = ftello(fFile);
  96         return result >= 0 ? result : errno;
  97 }
  98
  99
 100 status_t
 101 BFileIO::SetSize(off_t size)
 102 {
 103         return B_UNSUPPORTED;
 104 }
 105
 106
 107 status_t
 108 BFileIO::GetSize(off_t* _size) const
 109 {
 110         // save the current position and seek to the end
 111         off_t position = _Seek(0, SEEK_END);
 112         if (position < 0)
 113                 return position;
 114
 115         // get the size (position at end) and seek back
 116         off_t size = _Seek(position, SEEK_SET);
 117         if (size < 0)
 118                 return size;
 119
 120         *_size = size;
 121         return B_OK;
 122 }
 123
 124
 125 off_t
 126 BFileIO::_Seek(off_t position, uint32 seekMode) const
 127 {
 128         // save the current position
 129         off_t oldPosition = ftello(fFile);
 130         if (oldPosition < 0)
 131                 return errno;
 132
 133         // seek to the requested position
 134         if (fseeko(fFile, position, seekMode) < 0)
 135                 return errno;
 136
 137         return oldPosition;
 138 }