public unsafe bool Read(long pageNumber, byte *buffer, int count)
{
if (_fdReads == -1)
{
_fdReads = Syscall.open(_filename, OpenFlags.O_RDONLY);
if (_fdReads == -1)
{
PosixHelper.ThrowLastError(Marshal.GetLastWin32Error());
}
}
long position = pageNumber * AbstractPager.PageSize;
while (count > 0)
{
var result = Syscall.pread(_fdReads, buffer, (ulong)count, position);
if (result == 0) //eof
{
return(false);
}
count -= (int)result;
buffer += result;
position += result;
}
return(true);
}
public unsafe bool Read(byte *buffer, long numOfBytes, long offsetInFile)
{
if (_fdReads == -1)
{
_fdReads = Syscall.open(_filename.FullPath, OpenFlags.O_RDONLY, FilePermissions.S_IRUSR);
if (_fdReads == -1)
{
var err = Marshal.GetLastWin32Error();
Syscall.ThrowLastError(err, "when opening " + _filename);
}
}
while (numOfBytes > 0)
{
var result = Syscall.pread(_fdReads, buffer, (ulong)numOfBytes, offsetInFile);
if (result == 0) //eof
{
return(false);
}
numOfBytes -= result;
buffer += result;
offsetInFile += result;
}
return(true);
}
public unsafe bool Read(long pageNumber, byte *buffer, int count)
{
if (_fdReads == -1)
{
_fdReads = Syscall.open(_filename, OpenFlags.O_RDONLY, FilePermissions.S_IRUSR);
if (_fdReads == -1)
{
var err = Marshal.GetLastWin32Error();
PosixHelper.ThrowLastError(err, "when opening " + _filename);
}
}
long position = pageNumber * _options.PageSize;
while (count > 0)
{
var result = Syscall.pread(_fdReads, buffer, (ulong)count, position);
if (result == 0) //eof
{
return(false);
}
count -= (int)result;
buffer += result;
position += result;
}
return(true);
}
