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Differential D109923 Diff 373100 llvm/include/llvm/Support/BinaryItemStream.h

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llvm/include/llvm/Support/BinaryItemStream.h

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template <typename T, typename Traits = BinaryItemTraits<T>> template <typename T, typename Traits = BinaryItemTraits<T>>
class BinaryItemStream : public BinaryStream { class BinaryItemStream : public BinaryStream {
public: public:
explicit BinaryItemStream(llvm::support::endianness Endian) explicit BinaryItemStream(llvm::support::endianness Endian)
: Endian(Endian) {} : Endian(Endian) {}
llvm::support::endianness getEndian() const override { return Endian; } llvm::support::endianness getEndian() const override { return Endian; }
Error readBytes(uint32_t Offset, uint32_t Size, Error readBytes(uint64_t Offset, uint64_t Size,
ArrayRef<uint8_t> &Buffer) override { ArrayRef<uint8_t> &Buffer) override {
auto ExpectedIndex = translateOffsetIndex(Offset); auto ExpectedIndex = translateOffsetIndex(Offset);
if (!ExpectedIndex) if (!ExpectedIndex)
return ExpectedIndex.takeError(); return ExpectedIndex.takeError();
const auto &Item = Items[*ExpectedIndex]; const auto &Item = Items[*ExpectedIndex];
if (auto EC = checkOffsetForRead(Offset, Size)) if (auto EC = checkOffsetForRead(Offset, Size))
return EC; return EC;
if (Size > Traits::length(Item)) if (Size > Traits::length(Item))
return make_error<BinaryStreamError>(stream_error_code::stream_too_short); return make_error<BinaryStreamError>(stream_error_code::stream_too_short);
Buffer = Traits::bytes(Item).take_front(Size); Buffer = Traits::bytes(Item).take_front(Size);
return Error::success(); return Error::success();
} }
Error readLongestContiguousChunk(uint32_t Offset, Error readLongestContiguousChunk(uint64_t Offset,
ArrayRef<uint8_t> &Buffer) override { ArrayRef<uint8_t> &Buffer) override {
auto ExpectedIndex = translateOffsetIndex(Offset); auto ExpectedIndex = translateOffsetIndex(Offset);
if (!ExpectedIndex) if (!ExpectedIndex)
return ExpectedIndex.takeError(); return ExpectedIndex.takeError();
Buffer = Traits::bytes(Items[*ExpectedIndex]); Buffer = Traits::bytes(Items[*ExpectedIndex]);
return Error::success(); return Error::success();
} }
void setItems(ArrayRef<T> ItemArray) { void setItems(ArrayRef<T> ItemArray) {
Items = ItemArray; Items = ItemArray;
computeItemOffsets(); computeItemOffsets();
} }
uint32_t getLength() override { uint64_t getLength() override {
return ItemEndOffsets.empty() ? 0 : ItemEndOffsets.back(); return ItemEndOffsets.empty() ? 0 : ItemEndOffsets.back();
} }
private: private:
void computeItemOffsets() { void computeItemOffsets() {
ItemEndOffsets.clear(); ItemEndOffsets.clear();
ItemEndOffsets.reserve(Items.size()); ItemEndOffsets.reserve(Items.size());
uint32_t CurrentOffset = 0; uint64_t CurrentOffset = 0;
for (const auto &Item : Items) { for (const auto &Item : Items) {
uint32_t Len = Traits::length(Item); uint64_t Len = Traits::length(Item);
assert(Len > 0 && "no empty items"); assert(Len > 0 && "no empty items");
CurrentOffset += Len; CurrentOffset += Len;
ItemEndOffsets.push_back(CurrentOffset); ItemEndOffsets.push_back(CurrentOffset);
} }
} }
Expected<uint32_t> translateOffsetIndex(uint32_t Offset) { Expected<uint32_t> translateOffsetIndex(uint64_t Offset) {
// Make sure the offset is somewhere in our items array. // Make sure the offset is somewhere in our items array.
if (Offset >= getLength()) if (Offset >= getLength())
return make_error<BinaryStreamError>(stream_error_code::stream_too_short); return make_error<BinaryStreamError>(stream_error_code::stream_too_short);
++Offset; ++Offset;
auto Iter = llvm::lower_bound(ItemEndOffsets, Offset); auto Iter = llvm::lower_bound(ItemEndOffsets, Offset);
size_t Idx = std::distance(ItemEndOffsets.begin(), Iter); size_t Idx = std::distance(ItemEndOffsets.begin(), Iter);
assert(Idx < Items.size() && "binary search for offset failed"); assert(Idx < Items.size() && "binary search for offset failed");
return Idx; return Idx;
} }
llvm::support::endianness Endian; llvm::support::endianness Endian;
ArrayRef<T> Items; ArrayRef<T> Items;
// Sorted vector of offsets to accelerate lookup. // Sorted vector of offsets to accelerate lookup.
std::vector<uint32_t> ItemEndOffsets; std::vector<uint64_t> ItemEndOffsets;
}; };
} // end namespace llvm } // end namespace llvm
#endif // LLVM_SUPPORT_BINARYITEMSTREAM_H #endif // LLVM_SUPPORT_BINARYITEMSTREAM_H