forked from OSchip/llvm-project
416 lines
16 KiB
C++
416 lines
16 KiB
C++
//===- MappedBlockStream.cpp - Reads stream data from an MSF file ---------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/DebugInfo/MSF/MappedBlockStream.h"
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#include "llvm/DebugInfo/MSF/IMSFFile.h"
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#include "llvm/DebugInfo/MSF/MSFCommon.h"
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#include "llvm/DebugInfo/MSF/MSFError.h"
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#include "llvm/DebugInfo/MSF/MSFStreamLayout.h"
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using namespace llvm;
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using namespace llvm::msf;
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namespace {
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template <typename Base> class MappedBlockStreamImpl : public Base {
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public:
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template <typename... Args>
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MappedBlockStreamImpl(Args &&... Params)
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: Base(std::forward<Args>(Params)...) {}
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};
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}
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static void initializeFpmStreamLayout(const MSFLayout &Layout,
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MSFStreamLayout &FpmLayout) {
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uint32_t NumFpmIntervals = msf::getNumFpmIntervals(Layout);
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support::ulittle32_t FpmBlock = Layout.SB->FreeBlockMapBlock;
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assert(FpmBlock == 1 || FpmBlock == 2);
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while (NumFpmIntervals > 0) {
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FpmLayout.Blocks.push_back(FpmBlock);
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FpmBlock += msf::getFpmIntervalLength(Layout);
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--NumFpmIntervals;
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}
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FpmLayout.Length = msf::getFullFpmByteSize(Layout);
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}
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typedef std::pair<uint32_t, uint32_t> Interval;
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static Interval intersect(const Interval &I1, const Interval &I2) {
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return std::make_pair(std::max(I1.first, I2.first),
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std::min(I1.second, I2.second));
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}
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MappedBlockStream::MappedBlockStream(uint32_t BlockSize, uint32_t NumBlocks,
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const MSFStreamLayout &Layout,
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const ReadableStream &MsfData)
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: BlockSize(BlockSize), NumBlocks(NumBlocks), StreamLayout(Layout),
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MsfData(MsfData) {}
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std::unique_ptr<MappedBlockStream>
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MappedBlockStream::createStream(uint32_t BlockSize, uint32_t NumBlocks,
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const MSFStreamLayout &Layout,
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const ReadableStream &MsfData) {
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return llvm::make_unique<MappedBlockStreamImpl<MappedBlockStream>>(
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BlockSize, NumBlocks, Layout, MsfData);
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}
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std::unique_ptr<MappedBlockStream>
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MappedBlockStream::createIndexedStream(const MSFLayout &Layout,
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const ReadableStream &MsfData,
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uint32_t StreamIndex) {
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assert(StreamIndex < Layout.StreamMap.size() && "Invalid stream index");
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MSFStreamLayout SL;
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SL.Blocks = Layout.StreamMap[StreamIndex];
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SL.Length = Layout.StreamSizes[StreamIndex];
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return llvm::make_unique<MappedBlockStreamImpl<MappedBlockStream>>(
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Layout.SB->BlockSize, Layout.SB->NumBlocks, SL, MsfData);
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}
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std::unique_ptr<MappedBlockStream>
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MappedBlockStream::createDirectoryStream(const MSFLayout &Layout,
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const ReadableStream &MsfData) {
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MSFStreamLayout SL;
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SL.Blocks = Layout.DirectoryBlocks;
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SL.Length = Layout.SB->NumDirectoryBytes;
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return createStream(Layout.SB->BlockSize, Layout.SB->NumBlocks, SL, MsfData);
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}
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std::unique_ptr<MappedBlockStream>
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MappedBlockStream::createFpmStream(const MSFLayout &Layout,
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const ReadableStream &MsfData) {
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MSFStreamLayout SL;
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initializeFpmStreamLayout(Layout, SL);
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return createStream(Layout.SB->BlockSize, Layout.SB->NumBlocks, SL, MsfData);
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}
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Error MappedBlockStream::readBytes(uint32_t Offset, uint32_t Size,
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ArrayRef<uint8_t> &Buffer) const {
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// Make sure we aren't trying to read beyond the end of the stream.
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if (Size > StreamLayout.Length)
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return make_error<MSFError>(msf_error_code::insufficient_buffer);
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if (Offset > StreamLayout.Length - Size)
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return make_error<MSFError>(msf_error_code::insufficient_buffer);
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if (tryReadContiguously(Offset, Size, Buffer))
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return Error::success();
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auto CacheIter = CacheMap.find(Offset);
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if (CacheIter != CacheMap.end()) {
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// Try to find an alloc that was large enough for this request.
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for (auto &Entry : CacheIter->second) {
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if (Entry.size() >= Size) {
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Buffer = Entry.slice(0, Size);
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return Error::success();
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}
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}
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}
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// We couldn't find a buffer that started at the correct offset (the most
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// common scenario). Try to see if there is a buffer that starts at some
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// other offset but overlaps the desired range.
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for (auto &CacheItem : CacheMap) {
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Interval RequestExtent = std::make_pair(Offset, Offset + Size);
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// We already checked this one on the fast path above.
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if (CacheItem.first == Offset)
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continue;
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// If the initial extent of the cached item is beyond the ending extent
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// of the request, there is no overlap.
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if (CacheItem.first >= Offset + Size)
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continue;
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// We really only have to check the last item in the list, since we append
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// in order of increasing length.
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if (CacheItem.second.empty())
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continue;
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auto CachedAlloc = CacheItem.second.back();
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// If the initial extent of the request is beyond the ending extent of
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// the cached item, there is no overlap.
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Interval CachedExtent =
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std::make_pair(CacheItem.first, CacheItem.first + CachedAlloc.size());
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if (RequestExtent.first >= CachedExtent.first + CachedExtent.second)
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continue;
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Interval Intersection = intersect(CachedExtent, RequestExtent);
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// Only use this if the entire request extent is contained in the cached
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// extent.
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if (Intersection != RequestExtent)
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continue;
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uint32_t CacheRangeOffset =
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AbsoluteDifference(CachedExtent.first, Intersection.first);
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Buffer = CachedAlloc.slice(CacheRangeOffset, Size);
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return Error::success();
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}
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// Otherwise allocate a large enough buffer in the pool, memcpy the data
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// into it, and return an ArrayRef to that. Do not touch existing pool
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// allocations, as existing clients may be holding a pointer which must
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// not be invalidated.
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uint8_t *WriteBuffer = static_cast<uint8_t *>(Pool.Allocate(Size, 8));
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if (auto EC = readBytes(Offset, MutableArrayRef<uint8_t>(WriteBuffer, Size)))
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return EC;
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if (CacheIter != CacheMap.end()) {
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CacheIter->second.emplace_back(WriteBuffer, Size);
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} else {
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std::vector<CacheEntry> List;
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List.emplace_back(WriteBuffer, Size);
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CacheMap.insert(std::make_pair(Offset, List));
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}
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Buffer = ArrayRef<uint8_t>(WriteBuffer, Size);
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return Error::success();
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}
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Error MappedBlockStream::readLongestContiguousChunk(
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uint32_t Offset, ArrayRef<uint8_t> &Buffer) const {
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// Make sure we aren't trying to read beyond the end of the stream.
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if (Offset >= StreamLayout.Length)
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return make_error<MSFError>(msf_error_code::insufficient_buffer);
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uint32_t First = Offset / BlockSize;
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uint32_t Last = First;
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while (Last < NumBlocks - 1) {
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if (StreamLayout.Blocks[Last] != StreamLayout.Blocks[Last + 1] - 1)
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break;
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++Last;
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}
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uint32_t OffsetInFirstBlock = Offset % BlockSize;
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uint32_t BytesFromFirstBlock = BlockSize - OffsetInFirstBlock;
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uint32_t BlockSpan = Last - First + 1;
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uint32_t ByteSpan = BytesFromFirstBlock + (BlockSpan - 1) * BlockSize;
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ArrayRef<uint8_t> BlockData;
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uint32_t MsfOffset = blockToOffset(StreamLayout.Blocks[First], BlockSize);
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if (auto EC = MsfData.readBytes(MsfOffset, BlockSize, BlockData))
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return EC;
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BlockData = BlockData.drop_front(OffsetInFirstBlock);
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Buffer = ArrayRef<uint8_t>(BlockData.data(), ByteSpan);
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return Error::success();
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}
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uint32_t MappedBlockStream::getLength() const { return StreamLayout.Length; }
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bool MappedBlockStream::tryReadContiguously(uint32_t Offset, uint32_t Size,
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ArrayRef<uint8_t> &Buffer) const {
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if (Size == 0) {
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Buffer = ArrayRef<uint8_t>();
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return true;
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}
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// Attempt to fulfill the request with a reference directly into the stream.
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// This can work even if the request crosses a block boundary, provided that
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// all subsequent blocks are contiguous. For example, a 10k read with a 4k
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// block size can be filled with a reference if, from the starting offset,
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// 3 blocks in a row are contiguous.
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uint32_t BlockNum = Offset / BlockSize;
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uint32_t OffsetInBlock = Offset % BlockSize;
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uint32_t BytesFromFirstBlock = std::min(Size, BlockSize - OffsetInBlock);
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uint32_t NumAdditionalBlocks =
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llvm::alignTo(Size - BytesFromFirstBlock, BlockSize) / BlockSize;
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uint32_t RequiredContiguousBlocks = NumAdditionalBlocks + 1;
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uint32_t E = StreamLayout.Blocks[BlockNum];
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for (uint32_t I = 0; I < RequiredContiguousBlocks; ++I, ++E) {
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if (StreamLayout.Blocks[I + BlockNum] != E)
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return false;
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}
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// Read out the entire block where the requested offset starts. Then drop
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// bytes from the beginning so that the actual starting byte lines up with
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// the requested starting byte. Then, since we know this is a contiguous
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// cross-block span, explicitly resize the ArrayRef to cover the entire
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// request length.
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ArrayRef<uint8_t> BlockData;
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uint32_t FirstBlockAddr = StreamLayout.Blocks[BlockNum];
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uint32_t MsfOffset = blockToOffset(FirstBlockAddr, BlockSize);
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if (auto EC = MsfData.readBytes(MsfOffset, BlockSize, BlockData)) {
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consumeError(std::move(EC));
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return false;
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}
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BlockData = BlockData.drop_front(OffsetInBlock);
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Buffer = ArrayRef<uint8_t>(BlockData.data(), Size);
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return true;
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}
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Error MappedBlockStream::readBytes(uint32_t Offset,
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MutableArrayRef<uint8_t> Buffer) const {
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uint32_t BlockNum = Offset / BlockSize;
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uint32_t OffsetInBlock = Offset % BlockSize;
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// Make sure we aren't trying to read beyond the end of the stream.
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if (Buffer.size() > StreamLayout.Length)
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return make_error<MSFError>(msf_error_code::insufficient_buffer);
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if (Offset > StreamLayout.Length - Buffer.size())
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return make_error<MSFError>(msf_error_code::insufficient_buffer);
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uint32_t BytesLeft = Buffer.size();
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uint32_t BytesWritten = 0;
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uint8_t *WriteBuffer = Buffer.data();
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while (BytesLeft > 0) {
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uint32_t StreamBlockAddr = StreamLayout.Blocks[BlockNum];
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ArrayRef<uint8_t> BlockData;
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uint32_t Offset = blockToOffset(StreamBlockAddr, BlockSize);
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if (auto EC = MsfData.readBytes(Offset, BlockSize, BlockData))
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return EC;
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const uint8_t *ChunkStart = BlockData.data() + OffsetInBlock;
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uint32_t BytesInChunk = std::min(BytesLeft, BlockSize - OffsetInBlock);
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::memcpy(WriteBuffer + BytesWritten, ChunkStart, BytesInChunk);
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BytesWritten += BytesInChunk;
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BytesLeft -= BytesInChunk;
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++BlockNum;
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OffsetInBlock = 0;
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}
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return Error::success();
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}
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uint32_t MappedBlockStream::getNumBytesCopied() const {
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return static_cast<uint32_t>(Pool.getBytesAllocated());
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}
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void MappedBlockStream::invalidateCache() { CacheMap.shrink_and_clear(); }
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void MappedBlockStream::fixCacheAfterWrite(uint32_t Offset,
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ArrayRef<uint8_t> Data) const {
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// If this write overlapped a read which previously came from the pool,
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// someone may still be holding a pointer to that alloc which is now invalid.
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// Compute the overlapping range and update the cache entry, so any
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// outstanding buffers are automatically updated.
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for (const auto &MapEntry : CacheMap) {
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// If the end of the written extent precedes the beginning of the cached
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// extent, ignore this map entry.
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if (Offset + Data.size() < MapEntry.first)
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continue;
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for (const auto &Alloc : MapEntry.second) {
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// If the end of the cached extent precedes the beginning of the written
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// extent, ignore this alloc.
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if (MapEntry.first + Alloc.size() < Offset)
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continue;
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// If we get here, they are guaranteed to overlap.
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Interval WriteInterval = std::make_pair(Offset, Offset + Data.size());
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Interval CachedInterval =
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std::make_pair(MapEntry.first, MapEntry.first + Alloc.size());
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// If they overlap, we need to write the new data into the overlapping
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// range.
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auto Intersection = intersect(WriteInterval, CachedInterval);
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assert(Intersection.first <= Intersection.second);
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uint32_t Length = Intersection.second - Intersection.first;
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uint32_t SrcOffset =
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AbsoluteDifference(WriteInterval.first, Intersection.first);
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uint32_t DestOffset =
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AbsoluteDifference(CachedInterval.first, Intersection.first);
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::memcpy(Alloc.data() + DestOffset, Data.data() + SrcOffset, Length);
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}
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}
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}
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WritableMappedBlockStream::WritableMappedBlockStream(
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uint32_t BlockSize, uint32_t NumBlocks, const MSFStreamLayout &Layout,
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const WritableStream &MsfData)
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: ReadInterface(BlockSize, NumBlocks, Layout, MsfData),
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WriteInterface(MsfData) {}
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std::unique_ptr<WritableMappedBlockStream>
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WritableMappedBlockStream::createStream(uint32_t BlockSize, uint32_t NumBlocks,
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const MSFStreamLayout &Layout,
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const WritableStream &MsfData) {
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return llvm::make_unique<MappedBlockStreamImpl<WritableMappedBlockStream>>(
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BlockSize, NumBlocks, Layout, MsfData);
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}
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std::unique_ptr<WritableMappedBlockStream>
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WritableMappedBlockStream::createIndexedStream(const MSFLayout &Layout,
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const WritableStream &MsfData,
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uint32_t StreamIndex) {
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assert(StreamIndex < Layout.StreamMap.size() && "Invalid stream index");
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MSFStreamLayout SL;
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SL.Blocks = Layout.StreamMap[StreamIndex];
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SL.Length = Layout.StreamSizes[StreamIndex];
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return createStream(Layout.SB->BlockSize, Layout.SB->NumBlocks, SL, MsfData);
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}
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std::unique_ptr<WritableMappedBlockStream>
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WritableMappedBlockStream::createDirectoryStream(
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const MSFLayout &Layout, const WritableStream &MsfData) {
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MSFStreamLayout SL;
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SL.Blocks = Layout.DirectoryBlocks;
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SL.Length = Layout.SB->NumDirectoryBytes;
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return createStream(Layout.SB->BlockSize, Layout.SB->NumBlocks, SL, MsfData);
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}
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std::unique_ptr<WritableMappedBlockStream>
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WritableMappedBlockStream::createFpmStream(const MSFLayout &Layout,
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const WritableStream &MsfData) {
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MSFStreamLayout SL;
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initializeFpmStreamLayout(Layout, SL);
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return createStream(Layout.SB->BlockSize, Layout.SB->NumBlocks, SL, MsfData);
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}
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Error WritableMappedBlockStream::readBytes(uint32_t Offset, uint32_t Size,
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ArrayRef<uint8_t> &Buffer) const {
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return ReadInterface.readBytes(Offset, Size, Buffer);
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}
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Error WritableMappedBlockStream::readLongestContiguousChunk(
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uint32_t Offset, ArrayRef<uint8_t> &Buffer) const {
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return ReadInterface.readLongestContiguousChunk(Offset, Buffer);
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}
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uint32_t WritableMappedBlockStream::getLength() const {
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return ReadInterface.getLength();
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}
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Error WritableMappedBlockStream::writeBytes(uint32_t Offset,
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ArrayRef<uint8_t> Buffer) const {
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// Make sure we aren't trying to write beyond the end of the stream.
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if (Buffer.size() > getStreamLength())
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return make_error<MSFError>(msf_error_code::insufficient_buffer);
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if (Offset > getStreamLayout().Length - Buffer.size())
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return make_error<MSFError>(msf_error_code::insufficient_buffer);
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uint32_t BlockNum = Offset / getBlockSize();
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uint32_t OffsetInBlock = Offset % getBlockSize();
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uint32_t BytesLeft = Buffer.size();
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uint32_t BytesWritten = 0;
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while (BytesLeft > 0) {
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uint32_t StreamBlockAddr = getStreamLayout().Blocks[BlockNum];
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uint32_t BytesToWriteInChunk =
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std::min(BytesLeft, getBlockSize() - OffsetInBlock);
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const uint8_t *Chunk = Buffer.data() + BytesWritten;
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ArrayRef<uint8_t> ChunkData(Chunk, BytesToWriteInChunk);
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uint32_t MsfOffset = blockToOffset(StreamBlockAddr, getBlockSize());
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MsfOffset += OffsetInBlock;
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if (auto EC = WriteInterface.writeBytes(MsfOffset, ChunkData))
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return EC;
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BytesLeft -= BytesToWriteInChunk;
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BytesWritten += BytesToWriteInChunk;
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++BlockNum;
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OffsetInBlock = 0;
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}
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ReadInterface.fixCacheAfterWrite(Offset, Buffer);
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return Error::success();
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}
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Error WritableMappedBlockStream::commit() const {
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return WriteInterface.commit();
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}
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