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https://fuchsia.googlesource.com/third_party/pigweed.googlesource.com/pigweed/pigweed
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f82d95b680
Changes the memory writer to use std::memmove to allow data to be staged to the unused portion of a MemoryWriter's buffer before it is written. This is useful for operations that require direct access to a buffer to build data before it is flushed to a MemoryWriter. No-Docs-Update-Reason: Optimization that shouldn't be advertised Change-Id: I3728e50e30031d7f87db43981827ef799fbce217 Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/40244 Reviewed-by: David Rogers <davidrogers@google.com> Commit-Queue: Armando Montanez <amontanez@google.com>
54 lines
1.5 KiB
C++
54 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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#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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std::memmove(dest_.data() + bytes_written_, data.data(), bytes_to_write);
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bytes_written_ += 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() == bytes_read_) {
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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() - bytes_read_);
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std::memcpy(dest.data(), source_.data() + bytes_read_, bytes_to_read);
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bytes_read_ += 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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