internal static unsafe void WriteAtOffset(SafeFileHandle handle, ReadOnlySpan <byte> buffer, long fileOffset)
{
while (!buffer.IsEmpty)
{
fixed(byte *bufPtr = &MemoryMarshal.GetReference(buffer))
{
// The Windows implementation uses WriteFile, which ignores the offset if the handle
// isn't seekable. We do the same manually with PWrite vs Write, in order to enable
// the function to be used by FileStream for all the same situations.
int bytesWritten = handle.CanSeek ?
Interop.Sys.PWrite(handle, bufPtr, GetNumberOfBytesToWrite(buffer.Length), fileOffset) :
Interop.Sys.Write(handle, bufPtr, GetNumberOfBytesToWrite(buffer.Length));
FileStreamHelpers.CheckFileCall(bytesWritten, handle.Path);
if (bytesWritten == buffer.Length)
{
break;
}
// The write completed successfully but for fewer bytes than requested.
// We need to try again for the remainder.
buffer = buffer.Slice(bytesWritten);
fileOffset += bytesWritten;
}
}
}
internal static long GetFileLength(SafeFileHandle handle)
{
int result = Interop.Sys.FStat(handle, out Interop.Sys.FileStatus status);
FileStreamHelpers.CheckFileCall(result, handle.Path);
return(status.Size);
}
internal static unsafe long ReadScatterAtOffset(SafeFileHandle handle, IReadOnlyList <Memory <byte> > buffers, long fileOffset)
{
MemoryHandle[] handles = new MemoryHandle[buffers.Count];
Span <Interop.Sys.IOVector> vectors = buffers.Count <= IovStackThreshold ? stackalloc Interop.Sys.IOVector[IovStackThreshold] : new Interop.Sys.IOVector[buffers.Count];
long result;
try
{
int buffersCount = buffers.Count;
for (int i = 0; i < buffersCount; i++)
{
Memory <byte> buffer = buffers[i];
MemoryHandle memoryHandle = buffer.Pin();
vectors[i] = new Interop.Sys.IOVector {
Base = (byte *)memoryHandle.Pointer, Count = (UIntPtr)buffer.Length
};
handles[i] = memoryHandle;
}
fixed(Interop.Sys.IOVector *pinnedVectors = &MemoryMarshal.GetReference(vectors))
{
result = Interop.Sys.PReadV(handle, pinnedVectors, buffers.Count, fileOffset);
}
}
finally
{
foreach (MemoryHandle memoryHandle in handles)
{
memoryHandle.Dispose();
}
}
return(FileStreamHelpers.CheckFileCall(result, handle.Path));
}
private static unsafe int ReadAtOffset(SafeFileHandle handle, Span <byte> buffer, long fileOffset)
{
fixed(byte *bufPtr = &MemoryMarshal.GetReference(buffer))
{
int result = Interop.Sys.PRead(handle, bufPtr, buffer.Length, fileOffset);
FileStreamHelpers.CheckFileCall(result, path: null);
return(result);
}
}
internal static unsafe int WriteAtOffset(SafeFileHandle handle, ReadOnlySpan <byte> buffer, long fileOffset)
{
fixed(byte *bufPtr = &MemoryMarshal.GetReference(buffer))
{
int result = Interop.Sys.PWrite(handle, bufPtr, buffer.Length, fileOffset);
FileStreamHelpers.CheckFileCall(result, handle.Path);
return(result);
}
}
internal static unsafe int ReadAtOffset(SafeFileHandle handle, Span <byte> buffer, long fileOffset)
{
fixed(byte *bufPtr = &MemoryMarshal.GetReference(buffer))
{
// The Windows implementation uses ReadFile, which ignores the offset if the handle
// isn't seekable. We do the same manually with PRead vs Read, in order to enable
// the function to be used by FileStream for all the same situations.
int result = handle.CanSeek ?
Interop.Sys.PRead(handle, bufPtr, buffer.Length, fileOffset) :
Interop.Sys.Read(handle, bufPtr, buffer.Length);
FileStreamHelpers.CheckFileCall(result, handle.Path);
return(result);
}
}
internal static unsafe void WriteAtOffset(SafeFileHandle handle, ReadOnlySpan <byte> buffer, long fileOffset)
{
while (!buffer.IsEmpty)
{
fixed(byte *bufPtr = &MemoryMarshal.GetReference(buffer))
{
// The Windows implementation uses WriteFile, which ignores the offset if the handle
// isn't seekable. We do the same manually with PWrite vs Write, in order to enable
// the function to be used by FileStream for all the same situations.
int bytesToWrite = GetNumberOfBytesToWrite(buffer.Length);
int bytesWritten;
if (handle.SupportsRandomAccess)
{
bytesWritten = Interop.Sys.PWrite(handle, bufPtr, bytesToWrite, fileOffset);
if (bytesWritten == -1)
{
// We need to fallback to the non-offset version for certain file types
// e.g: character devices (such as /dev/tty), pipes, and sockets.
Interop.ErrorInfo errorInfo = Interop.Sys.GetLastErrorInfo();
if (errorInfo.Error == Interop.Error.ENXIO ||
errorInfo.Error == Interop.Error.ESPIPE)
{
handle.SupportsRandomAccess = false;
bytesWritten = Interop.Sys.Write(handle, bufPtr, bytesToWrite);
}
}
}
else
{
bytesWritten = Interop.Sys.Write(handle, bufPtr, bytesToWrite);
}
FileStreamHelpers.CheckFileCall(bytesWritten, handle.Path);
if (bytesWritten == buffer.Length)
{
break;
}
// The write completed successfully but for fewer bytes than requested.
// We need to try again for the remainder.
buffer = buffer.Slice(bytesWritten);
fileOffset += bytesWritten;
}
}
}
internal static unsafe int ReadAtOffset(SafeFileHandle handle, Span <byte> buffer, long fileOffset)
{
fixed(byte *bufPtr = &MemoryMarshal.GetReference(buffer))
{
// The Windows implementation uses ReadFile, which ignores the offset if the handle
// isn't seekable. We do the same manually with PRead vs Read, in order to enable
// the function to be used by FileStream for all the same situations.
int result;
if (handle.SupportsRandomAccess)
{
// Try pread for seekable files.
result = Interop.Sys.PRead(handle, bufPtr, buffer.Length, fileOffset);
if (result == -1)
{
// We need to fallback to the non-offset version for certain file types
// e.g: character devices (such as /dev/tty), pipes, and sockets.
Interop.ErrorInfo errorInfo = Interop.Sys.GetLastErrorInfo();
if (errorInfo.Error == Interop.Error.ENXIO ||
errorInfo.Error == Interop.Error.ESPIPE)
{
handle.SupportsRandomAccess = false;
result = Interop.Sys.Read(handle, bufPtr, buffer.Length);
}
}
}
else
{
result = Interop.Sys.Read(handle, bufPtr, buffer.Length);
}
FileStreamHelpers.CheckFileCall(result, handle.Path);
return(result);
}
}
internal static unsafe void WriteGatherAtOffset(SafeFileHandle handle, IReadOnlyList <ReadOnlyMemory <byte> > buffers, long fileOffset)
{
int buffersCount = buffers.Count;
if (buffersCount == 0)
{
return;
}
var handles = new MemoryHandle[buffersCount];
Span <Interop.Sys.IOVector> vectors = buffersCount <= IovStackThreshold ?
stackalloc Interop.Sys.IOVector[IovStackThreshold] :
new Interop.Sys.IOVector[buffersCount];
try
{
int buffersOffset = 0, firstBufferOffset = 0;
while (true)
{
long totalBytesToWrite = 0;
for (int i = buffersOffset; i < buffersCount; i++)
{
ReadOnlyMemory <byte> buffer = buffers[i];
totalBytesToWrite += buffer.Length;
MemoryHandle memoryHandle = buffer.Pin();
vectors[i] = new Interop.Sys.IOVector {
Base = firstBufferOffset + (byte *)memoryHandle.Pointer, Count = (UIntPtr)buffer.Length
};
handles[i] = memoryHandle;
firstBufferOffset = 0;
}
if (totalBytesToWrite == 0)
{
break;
}
long bytesWritten;
fixed(Interop.Sys.IOVector *pinnedVectors = &MemoryMarshal.GetReference(vectors))
{
bytesWritten = Interop.Sys.PWriteV(handle, pinnedVectors, buffersCount, fileOffset);
}
FileStreamHelpers.CheckFileCall(bytesWritten, handle.Path);
if (bytesWritten == totalBytesToWrite)
{
break;
}
// The write completed successfully but for fewer bytes than requested.
// We need to try again for the remainder.
for (int i = 0; i < buffersCount; i++)
{
int n = buffers[i].Length;
if (n <= bytesWritten)
{
buffersOffset++;
bytesWritten -= n;
if (bytesWritten == 0)
{
break;
}
}
else
{
firstBufferOffset = (int)(bytesWritten - n);
break;
}
}
}
}
finally
{
foreach (MemoryHandle memoryHandle in handles)
{
memoryHandle.Dispose();
}
}
}
internal static unsafe void SetFileLength(SafeFileHandle handle, long length) => FileStreamHelpers.CheckFileCall(Interop.Sys.FTruncate(handle, length), handle.Path);
