public static Task <byte[]> ReadAllBytesAsync(string path, CancellationToken cancellationToken = default(CancellationToken))
{
if (cancellationToken.IsCancellationRequested)
{
return(Task.FromCanceled <byte[]>(cancellationToken));
}
// SequentialScan is a perf hint that requires extra sys-call on non-Windows OSes.
FileOptions options = FileOptions.Asynchronous | (OperatingSystem.IsWindows() ? FileOptions.SequentialScan : FileOptions.None);
SafeFileHandle sfh = OpenHandle(path, FileMode.Open, FileAccess.Read, FileShare.Read, options);
long fileLength = 0L;
if (sfh.CanSeek && (fileLength = sfh.GetFileLength()) > Array.MaxLength)
{
sfh.Dispose();
return(Task.FromException <byte[]>(ExceptionDispatchInfo.SetCurrentStackTrace(new IOException(SR.IO_FileTooLong2GB))));
}
#if DEBUG
fileLength = 0; // improve the test coverage for InternalReadAllBytesUnknownLengthAsync
#endif
return(fileLength > 0 ?
InternalReadAllBytesAsync(sfh, (int)fileLength, cancellationToken) :
InternalReadAllBytesUnknownLengthAsync(sfh, cancellationToken));
}
public static byte[] ReadAllBytes(string path)
{
// SequentialScan is a perf hint that requires extra sys-call on non-Windows OSes.
FileOptions options = OperatingSystem.IsWindows() ? FileOptions.SequentialScan : FileOptions.None;
using (SafeFileHandle sfh = OpenHandle(path, FileMode.Open, FileAccess.Read, FileShare.Read, options))
{
long fileLength = 0;
if (sfh.CanSeek && (fileLength = sfh.GetFileLength()) > Array.MaxLength)
{
throw new IOException(SR.IO_FileTooLong2GB);
}
#if DEBUG
fileLength = 0; // improve the test coverage for ReadAllBytesUnknownLength
#endif
if (fileLength == 0)
{
// Some file systems (e.g. procfs on Linux) return 0 for length even when there's content; also there are non-seekable files.
// Thus we need to assume 0 doesn't mean empty.
return(ReadAllBytesUnknownLength(sfh));
}
int index = 0;
int count = (int)fileLength;
byte[] bytes = new byte[count];
while (count > 0)
{
int n = RandomAccess.ReadAtOffset(sfh, bytes.AsSpan(index, count), index);
if (n == 0)
{
ThrowHelper.ThrowEndOfFileException();
}
index += n;
count -= n;
}
return(bytes);
}
}
/// <summary>
/// Gets the length of the file in bytes.
/// </summary>
/// <param name="handle">The file handle.</param>
/// <returns>A long value representing the length of the file in bytes.</returns>
/// <exception cref="T:System.ArgumentNullException"><paramref name="handle" /> is <see langword="null" />.</exception>
/// <exception cref="T:System.ArgumentException"><paramref name="handle" /> is invalid.</exception>
/// <exception cref="T:System.ObjectDisposedException">The file is closed.</exception>
/// <exception cref="T:System.NotSupportedException">The file does not support seeking (pipe or socket).</exception>
public static long GetLength(SafeFileHandle handle)
{
ValidateInput(handle, fileOffset: 0);
return(handle.GetFileLength());
}
