66 lines
2.0 KiB
C++
66 lines
2.0 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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#include "pw_stream/memory_stream.h"
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#include <cstddef>
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#include <cstring>
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#include "pw_status/status_with_size.h"
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namespace pw::stream {
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Status MemoryWriter::DoWrite(ConstByteSpan data) {
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if (ConservativeWriteLimit() == 0) {
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return Status::OutOfRange();
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}
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if (ConservativeWriteLimit() < data.size_bytes()) {
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return Status::ResourceExhausted();
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}
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size_t bytes_to_write = data.size_bytes();
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if (bytes_to_write == 0) {
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// Calling memmove with a null pointer is undefined behavior, even when zero
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// bytes are moved. We must return early here to avoid performing such a
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// call when data is an empty span.
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return OkStatus();
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}
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std::memmove(dest_.data() + position_, data.data(), bytes_to_write);
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position_ += bytes_to_write;
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return OkStatus();
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}
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StatusWithSize MemoryReader::DoRead(ByteSpan dest) {
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if (source_.size_bytes() == position_) {
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return StatusWithSize::OutOfRange();
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}
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size_t bytes_to_read =
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std::min(dest.size_bytes(), source_.size_bytes() - position_);
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if (bytes_to_read == 0) {
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// Calling memcpy with a null pointer is undefined behavior, even when zero
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// bytes are copied. We must return early here to avoid performing such a
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// call when the dest span is empty.
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return StatusWithSize(0);
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}
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std::memcpy(dest.data(), source_.data() + position_, bytes_to_read);
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position_ += bytes_to_read;
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return StatusWithSize(bytes_to_read);
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}
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} // namespace pw::stream
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