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ff68452301
It is more efficient than llvm::AppendingBinaryByteStream if a lot of small data gets appended to it because it doesn't need to resize its buffer on each write.
70 lines
2.3 KiB
C++
70 lines
2.3 KiB
C++
//===-------- ExponentialGrowthAppendingBinaryByteStream.cpp --------------===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2018 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See https://swift.org/LICENSE.txt for license information
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// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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#include "swift/Basic/ExponentialGrowthAppendingBinaryByteStream.h"
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using namespace llvm;
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using namespace swift;
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Error ExponentialGrowthAppendingBinaryByteStream::readBytes(
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uint32_t Offset, uint32_t Size, ArrayRef<uint8_t> &Buffer) {
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if (Offset > this->Size)
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return make_error<BinaryStreamError>(stream_error_code::invalid_offset);
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if (Offset + Size > this->Size)
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return make_error<BinaryStreamError>(stream_error_code::stream_too_short);
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Buffer = ArrayRef<uint8_t>(Data + Offset, Size);
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return Error::success();
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}
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Error ExponentialGrowthAppendingBinaryByteStream::readLongestContiguousChunk(
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uint32_t Offset, ArrayRef<uint8_t> &Buffer) {
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if (Offset > this->Size)
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return make_error<BinaryStreamError>(stream_error_code::invalid_offset);
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Buffer = ArrayRef<uint8_t>(Data + Offset, Size - Offset);
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return Error::success();
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}
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void ExponentialGrowthAppendingBinaryByteStream::reserve(size_t Size) {
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if (Size <= ReservedBufferSize) {
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// The buffer is already large enough. Nothing to do.
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return;
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}
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Data = (uint8_t *)realloc(Data, Size);
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ReservedBufferSize = Size;
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}
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Error ExponentialGrowthAppendingBinaryByteStream::writeBytes(
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uint32_t Offset, ArrayRef<uint8_t> Buffer) {
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if (Buffer.empty())
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return Error::success();
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if (Offset > Size)
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return make_error<BinaryStreamError>(stream_error_code::invalid_offset);
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// Resize the internal buffer if needed.
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uint32_t RequiredSize = Offset + Buffer.size();
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uint32_t NewBufferSize = ReservedBufferSize;
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// Double the buffer size until its size is sufficient to hold the new data.
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while (RequiredSize > NewBufferSize) {
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NewBufferSize *= 2;
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}
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reserve(NewBufferSize);
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Size += Buffer.size();
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::memcpy(Data + Offset, Buffer.data(), Buffer.size());
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return Error::success();
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}
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