public static void WriteAllBytes(string path, byte[] bytes)
{
ArgumentException.ThrowIfNullOrEmpty(path);
ArgumentNullException.ThrowIfNull(bytes);
using SafeFileHandle sfh = OpenHandle(path, FileMode.Create, FileAccess.Write, FileShare.Read);
RandomAccess.WriteAtOffset(sfh, bytes, 0);
}
private static void WriteToFile(string path, FileMode mode, string?contents, Encoding encoding)
{
ReadOnlySpan <byte> preamble = encoding.GetPreamble();
int preambleSize = preamble.Length;
using SafeFileHandle fileHandle = OpenHandle(path, mode, FileAccess.Write, FileShare.Read, FileOptions.None, GetPreallocationSize(mode, contents, encoding, preambleSize));
long fileOffset = mode == FileMode.Append && fileHandle.CanSeek ? RandomAccess.GetLength(fileHandle) : 0;
if (string.IsNullOrEmpty(contents))
{
if (preambleSize > 0 && // even if the content is empty, we want to store the preamble
fileOffset == 0) // if we're appending to a file that already has data, don't write the preamble.
{
RandomAccess.WriteAtOffset(fileHandle, preamble, fileOffset);
}
return;
}
int bytesNeeded = preambleSize + encoding.GetMaxByteCount(Math.Min(contents.Length, ChunkSize));
byte[]? rentedBytes = null;
Span <byte> bytes = bytesNeeded <= 1024 ? stackalloc byte[1024] : (rentedBytes = ArrayPool <byte> .Shared.Rent(bytesNeeded));
try
{
if (fileOffset == 0)
{
preamble.CopyTo(bytes);
}
else
{
preambleSize = 0; // don't append preamble to a non-empty file
}
Encoder encoder = encoding.GetEncoder();
ReadOnlySpan <char> remaining = contents;
while (!remaining.IsEmpty)
{
ReadOnlySpan <char> toEncode = remaining.Slice(0, Math.Min(remaining.Length, ChunkSize));
remaining = remaining.Slice(toEncode.Length);
int encoded = encoder.GetBytes(toEncode, bytes.Slice(preambleSize), flush: remaining.IsEmpty);
Span <byte> toStore = bytes.Slice(0, preambleSize + encoded);
RandomAccess.WriteAtOffset(fileHandle, toStore, fileOffset);
fileOffset += toStore.Length;
preambleSize = 0;
}
}
finally
{
if (rentedBytes is not null)
{
ArrayPool <byte> .Shared.Return(rentedBytes);
}
}
}
private static async Task WriteToFileAsync(string path, FileMode mode, string?contents, Encoding encoding, CancellationToken cancellationToken)
{
ReadOnlyMemory <byte> preamble = encoding.GetPreamble();
int preambleSize = preamble.Length;
using SafeFileHandle fileHandle = OpenHandle(path, mode, FileAccess.Write, FileShare.Read, FileOptions.Asynchronous, GetPreallocationSize(mode, contents, encoding, preambleSize));
long fileOffset = mode == FileMode.Append && fileHandle.CanSeek ? RandomAccess.GetLength(fileHandle) : 0;
if (string.IsNullOrEmpty(contents))
{
if (preambleSize > 0 && // even if the content is empty, we want to store the preamble
fileOffset == 0) // if we're appending to a file that already has data, don't write the preamble.
{
await RandomAccess.WriteAtOffsetAsync(fileHandle, preamble, fileOffset, cancellationToken).ConfigureAwait(false);
}
return;
}
byte[] bytes = ArrayPool <byte> .Shared.Rent(preambleSize + encoding.GetMaxByteCount(Math.Min(contents.Length, ChunkSize)));
try
{
if (fileOffset == 0)
{
preamble.CopyTo(bytes);
}
else
{
preambleSize = 0; // don't append preamble to a non-empty file
}
Encoder encoder = encoding.GetEncoder();
ReadOnlyMemory <char> remaining = contents.AsMemory();
while (!remaining.IsEmpty)
{
ReadOnlyMemory <char> toEncode = remaining.Slice(0, Math.Min(remaining.Length, ChunkSize));
remaining = remaining.Slice(toEncode.Length);
int encoded = encoder.GetBytes(toEncode.Span, bytes.AsSpan(preambleSize), flush: remaining.IsEmpty);
ReadOnlyMemory <byte> toStore = new ReadOnlyMemory <byte>(bytes, 0, preambleSize + encoded);
await RandomAccess.WriteAtOffsetAsync(fileHandle, toStore, fileOffset, cancellationToken).ConfigureAwait(false);
fileOffset += toStore.Length;
preambleSize = 0;
}
}
finally
{
ArrayPool <byte> .Shared.Return(bytes);
}
}
private static async Task <byte[]> InternalReadAllBytesUnknownLengthAsync(SafeFileHandle sfh, CancellationToken cancellationToken)
{
byte[] rentedArray = ArrayPool <byte> .Shared.Rent(512);
try
{
int bytesRead = 0;
while (true)
{
if (bytesRead == rentedArray.Length)
{
uint newLength = (uint)rentedArray.Length * 2;
if (newLength > Array.MaxLength)
{
newLength = (uint)Math.Max(Array.MaxLength, rentedArray.Length + 1);
}
byte[] tmp = ArrayPool <byte> .Shared.Rent((int)newLength);
Buffer.BlockCopy(rentedArray, 0, tmp, 0, bytesRead);
byte[] toReturn = rentedArray;
rentedArray = tmp;
ArrayPool <byte> .Shared.Return(toReturn);
}
Debug.Assert(bytesRead < rentedArray.Length);
int n = await RandomAccess.ReadAtOffsetAsync(sfh, rentedArray.AsMemory(bytesRead), bytesRead, cancellationToken).ConfigureAwait(false);
if (n == 0)
{
return(rentedArray.AsSpan(0, bytesRead).ToArray());
}
bytesRead += n;
}
}
finally
{
sfh.Dispose();
ArrayPool <byte> .Shared.Return(rentedArray);
}
}
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);
}
}
private static async Task <byte[]> InternalReadAllBytesAsync(SafeFileHandle sfh, int count, CancellationToken cancellationToken)
{
using (sfh)
{
int index = 0;
byte[] bytes = new byte[count];
do
{
int n = await RandomAccess.ReadAtOffsetAsync(sfh, bytes.AsMemory(index), index, cancellationToken).ConfigureAwait(false);
if (n == 0)
{
ThrowHelper.ThrowEndOfFileException();
}
index += n;
} while (index < count);
return(bytes);
}
}
static async Task Core(string path, byte[] bytes, CancellationToken cancellationToken)
{
using SafeFileHandle sfh = OpenHandle(path, FileMode.Create, FileAccess.Write, FileShare.Read, FileOptions.Asynchronous);
await RandomAccess.WriteAtOffsetAsync(sfh, bytes, 0, cancellationToken).ConfigureAwait(false);
}