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