/// <summary>
/// Retrieves data from an array of buffers and writes the data to a file.
/// </summary>
/// <param name="segments">Array of pointers to data buffers.
/// Each buffer must be at least the size of a system memory page and must be aligned
/// on a system memory page size boundary <seealso cref="SystemPageSize"/>.
/// The system writes one system memory page of data into each buffer.
/// Buffers should not be deallocated or moved until operation is completed.</param>
/// <param name="fileOffset">File pointer</param>
/// <param name="callback">An optional asynchronous callback, to be called when the write is complete.</param>
/// <param name="state">A user-provided object that distinguishes this particular asynchronous write request from other requests.</param>
/// <returns>An IAsyncResult that represents the asynchronous write, which could still be pending.</returns>
public IAsyncResult BeginWriteGather(
IntPtr[] segments,
UInt64 fileOffset,
AsyncCallback callback,
object state)
{
if (segments == null)
{
throw new ArgumentNullException("segments");
}
CheckNotDisposed();
NativeMethods.FILE_SEGMENT_ELEMENT[] nativeSegments = new NativeMethods.FILE_SEGMENT_ELEMENT[segments.Length + 1];
for (int i = 0; i < segments.Length; i++)
{
nativeSegments[i].Buffer = segments[i];
}
UInt32 numberOfBytesToWrite = (uint)segments.Length * _systemPageSize;
AsyncJob job = null;
try
{
job = new AsyncJob(callback, state, fileOffset, nativeSegments);
bool result;
unsafe
{
fixed(NativeMethods.FILE_SEGMENT_ELEMENT *ps = &nativeSegments[0])
{
result = NativeMethods.WriteFileGather(_handle, ps, numberOfBytesToWrite, IntPtr.Zero, job.OverlappedPtr);
}
}
if (result)
{
job.CompleteSynchronously();
}
else
{
CheckErrorPending();
}
AsyncJob ret = job; job = null;
return(ret);
}
finally
{
if (job != null)
{
job.Dispose();
}
}
}
/// <summary>
/// Retrieves data from an array of buffers and writes the data to a file.
/// </summary>
/// <param name="segments">Array of pointers to data buffers.
/// Each buffer must be at least the size of a system memory page and must be aligned
/// on a system memory page size boundary <seealso cref="SystemPageSize"/>.
/// The system writes one system memory page of data into each buffer.
/// Buffers should not be deallocated or moved until operation is completed.</param>
/// <param name="fileOffset">File pointer</param>
/// <param name="callback">An optional asynchronous callback, to be called when the write is complete.</param>
/// <param name="state">A user-provided object that distinguishes this particular asynchronous write request from other requests.</param>
/// <returns>An IAsyncResult that represents the asynchronous write, which could still be pending.</returns>
public IAsyncResult BeginWriteGather(
IntPtr[] segments,
UInt64 fileOffset,
AsyncCallback callback,
object state) {
if (segments == null)
throw new ArgumentNullException("segments");
CheckNotDisposed();
NativeMethods.FILE_SEGMENT_ELEMENT[] nativeSegments = new NativeMethods.FILE_SEGMENT_ELEMENT[segments.Length + 1];
for (int i = 0; i < segments.Length; i++)
nativeSegments[i].Buffer = segments[i];
UInt32 numberOfBytesToWrite = (uint)segments.Length * _systemPageSize;
AsyncJob job = null;
try {
job = new AsyncJob(callback, state, fileOffset, nativeSegments);
bool result;
unsafe {
fixed (NativeMethods.FILE_SEGMENT_ELEMENT* ps = &nativeSegments[0]) {
result = NativeMethods.WriteFileGather(_handle, ps, numberOfBytesToWrite, IntPtr.Zero, job.OverlappedPtr);
}
}
if (result)
job.CompleteSynchronously();
else
CheckErrorPending();
AsyncJob ret = job; job = null;
return ret;
} finally {
if (job != null)
job.Dispose();
}
}
