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// Copyright 2020 The Pigweed Authors
// Licensed under the Apache License, Version 2.0 (the "License"); you may not
// use this file except in compliance with the License. You may obtain a copy of
// the License at
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
// License for the specific language governing permissions and limitations under
// the License.
#pragma once
#include <cstddef>
#include "pw_bytes/span.h"
#include "pw_polyfill/language_feature_macros.h"
#include "pw_span/span.h"
#include "pw_status/status.h"
#include "pw_status/status_with_size.h"
#include "pw_stream/stream.h"
namespace pw::stream {
// Stream that silently drops written data and returns nothing on reads, similar
// to /dev/null.
class NullStream final : public SeekableReaderWriter {
// Gives access to a global NullStream instance. It is not necessary to have
// multiple NullStream instances since they have no state and do nothing.
static NullStream& Instance() {
PW_CONSTINIT static NullStream stream;
return stream;
Status DoWrite(ConstByteSpan) final { return OkStatus(); }
StatusWithSize DoRead(ByteSpan) final { return StatusWithSize::OutOfRange(); }
Status DoSeek(ptrdiff_t, Whence) final { return OkStatus(); }
} // namespace pw::stream