/// having to specify a second template argument to VarStreamArray (documented
/// below).
template <typename T> struct VarStreamArrayExtractor {
- struct ContextType {};
-
// Method intentionally deleted. You must provide an explicit specialization
- // with one of the following two methods implemented.
- static Error extract(BinaryStreamRef Stream, uint32_t &Len, T &Item) = delete;
+ // with the following method implemented.
+ Error operator()(BinaryStreamRef Stream, uint32_t &Len,
+ T &Item) const = delete;
+};
+
+/// VarStreamArray represents an array of variable length records backed by a
+/// stream. This could be a contiguous sequence of bytes in memory, it could
+/// be a file on disk, or it could be a PDB stream where bytes are stored as
+/// discontiguous blocks in a file. Usually it is desirable to treat arrays
+/// as contiguous blocks of memory, but doing so with large PDB files, for
+/// example, could mean allocating huge amounts of memory just to allow
+/// re-ordering of stream data to be contiguous before iterating over it. By
+/// abstracting this out, we need not duplicate this memory, and we can
+/// iterate over arrays in arbitrarily formatted streams. Elements are parsed
+/// lazily on iteration, so there is no upfront cost associated with building
+/// or copying a VarStreamArray, no matter how large it may be.
+///
+/// You create a VarStreamArray by specifying a ValueType and an Extractor type.
+/// If you do not specify an Extractor type, you are expected to specialize
+/// VarStreamArrayExtractor<T> for your ValueType.
+///
+/// By default an Extractor is default constructed in the class, but in some
+/// cases you might find it useful for an Extractor to maintain state across
+/// extractions. In this case you can provide your own Extractor through a
+/// secondary constructor. The following examples show various ways of
+/// creating a VarStreamArray.
+///
+/// // Will use VarStreamArrayExtractor<MyType> as the extractor.
+/// VarStreamArray<MyType> MyTypeArray;
+///
+/// // Will use a default-constructed MyExtractor as the extractor.
+/// VarStreamArray<MyType, MyExtractor> MyTypeArray2;
+///
+/// // Will use the specific instance of MyExtractor provided.
+/// // MyExtractor need not be default-constructible in this case.
+/// MyExtractor E(SomeContext);
+/// VarStreamArray<MyType, MyExtractor> MyTypeArray3(E);
+///
+
+template <typename ValueType, typename Extractor> class VarStreamArrayIterator;
+
+template <typename ValueType,
+ typename Extractor = VarStreamArrayExtractor<ValueType>>
+class VarStreamArray {
+ friend class VarStreamArrayIterator<ValueType, Extractor>;
+
+public:
+ typedef VarStreamArrayIterator<ValueType, Extractor> Iterator;
+
+ VarStreamArray() = default;
+
+ explicit VarStreamArray(const Extractor &E) : E(E) {}
+
+ explicit VarStreamArray(BinaryStreamRef Stream) : Stream(Stream) {}
- static Error extract(BinaryStreamRef Stream, uint32_t &Len, T &Item,
- const ContextType &Ctx) = delete;
+ VarStreamArray(BinaryStreamRef Stream, const Extractor &E)
+ : Stream(Stream), E(E) {}
+
+ Iterator begin(bool *HadError = nullptr) const {
+ return Iterator(*this, E, HadError);
+ }
+
+ bool valid() const { return Stream.valid(); }
+
+ Iterator end() const { return Iterator(E); }
+
+ bool empty() const { return Stream.getLength() == 0; }
+
+ /// \brief given an offset into the array's underlying stream, return an
+ /// iterator to the record at that offset. This is considered unsafe
+ /// since the behavior is undefined if \p Offset does not refer to the
+ /// beginning of a valid record.
+ Iterator at(uint32_t Offset) const {
+ return Iterator(*this, E, Offset, nullptr);
+ }
+
+ const Extractor &getExtractor() const { return E; }
+ Extractor &getExtractor() { return E; }
+
+ BinaryStreamRef getUnderlyingStream() const { return Stream; }
+ void setUnderlyingStream(BinaryStreamRef S) { Stream = S; }
+
+private:
+ BinaryStreamRef Stream;
+ Extractor E;
};
-template <typename ArrayType, typename Value, typename Extractor,
- typename WrappedCtx>
+template <typename ValueType, typename Extractor>
class VarStreamArrayIterator
- : public iterator_facade_base<
- VarStreamArrayIterator<ArrayType, Value, Extractor, WrappedCtx>,
- std::forward_iterator_tag, Value> {
- typedef VarStreamArrayIterator<ArrayType, Value, Extractor, WrappedCtx>
- IterType;
+ : public iterator_facade_base<VarStreamArrayIterator<ValueType, Extractor>,
+ std::forward_iterator_tag, ValueType> {
+ typedef VarStreamArrayIterator<ValueType, Extractor> IterType;
+ typedef VarStreamArray<ValueType, Extractor> ArrayType;
public:
- VarStreamArrayIterator() = default;
- VarStreamArrayIterator(const ArrayType &Array, const WrappedCtx &Ctx,
- BinaryStreamRef Stream, bool *HadError = nullptr,
- uint32_t Offset = 0)
- : IterRef(Stream), Ctx(&Ctx), Array(&Array), AbsOffset(Offset),
- HadError(HadError) {
+ VarStreamArrayIterator(const ArrayType &Array, const Extractor &E,
+ bool *HadError)
+ : VarStreamArrayIterator(Array, E, 0, HadError) {}
+
+ VarStreamArrayIterator(const ArrayType &Array, const Extractor &E,
+ uint32_t Offset, bool *HadError)
+ : IterRef(Array.Stream.drop_front(Offset)), Array(&Array),
+ AbsOffset(Offset), HadError(HadError), Extract(E) {
if (IterRef.getLength() == 0)
moveToEnd();
else {
- auto EC = Ctx.template invoke<Extractor>(IterRef, ThisLen, ThisValue);
+ auto EC = Extract(IterRef, ThisLen, ThisValue);
if (EC) {
consumeError(std::move(EC));
markError();
}
}
- VarStreamArrayIterator(const ArrayType &Array, const WrappedCtx &Ctx,
- bool *HadError = nullptr)
- : VarStreamArrayIterator(Array, Ctx, Array.Stream, HadError) {}
-
- VarStreamArrayIterator(const WrappedCtx &Ctx) : Ctx(&Ctx) {}
- VarStreamArrayIterator(const VarStreamArrayIterator &Other) = default;
-
+ VarStreamArrayIterator() = default;
+ explicit VarStreamArrayIterator(const Extractor &E) : Extract(E) {}
~VarStreamArrayIterator() = default;
bool operator==(const IterType &R) const {
return false;
}
- const Value &operator*() const {
+ const ValueType &operator*() const {
assert(Array && !HasError);
return ThisValue;
}
- Value &operator*() {
+ ValueType &operator*() {
assert(Array && !HasError);
return ThisValue;
}
moveToEnd();
} else {
// There is some data after the current record.
- auto EC = Ctx->template invoke<Extractor>(IterRef, ThisLen, ThisValue);
+ auto EC = Extract(IterRef, ThisLen, ThisValue);
if (EC) {
consumeError(std::move(EC));
markError();
*HadError = true;
}
- Value ThisValue;
+ ValueType ThisValue;
BinaryStreamRef IterRef;
- const WrappedCtx *Ctx{nullptr};
+ Extractor Extract;
const ArrayType *Array{nullptr};
uint32_t ThisLen{0};
uint32_t AbsOffset{0};
bool *HadError{nullptr};
};
-template <typename T, typename Context> struct ContextWrapper {
- ContextWrapper() = default;
-
- explicit ContextWrapper(Context &&Ctx) : Ctx(Ctx) {}
-
- template <typename Extractor>
- Error invoke(BinaryStreamRef Stream, uint32_t &Len, T &Item) const {
- return Extractor::extract(Stream, Len, Item, Ctx);
- }
-
- Context Ctx;
-};
-
-template <typename T> struct ContextWrapper<T, void> {
- ContextWrapper() = default;
-
- template <typename Extractor>
- Error invoke(BinaryStreamRef Stream, uint32_t &Len, T &Item) const {
- return Extractor::extract(Stream, Len, Item);
- }
-};
-
-/// VarStreamArray represents an array of variable length records backed by a
-/// stream. This could be a contiguous sequence of bytes in memory, it could
-/// be a file on disk, or it could be a PDB stream where bytes are stored as
-/// discontiguous blocks in a file. Usually it is desirable to treat arrays
-/// as contiguous blocks of memory, but doing so with large PDB files, for
-/// example, could mean allocating huge amounts of memory just to allow
-/// re-ordering of stream data to be contiguous before iterating over it. By
-/// abstracting this out, we need not duplicate this memory, and we can
-/// iterate over arrays in arbitrarily formatted streams. Elements are parsed
-/// lazily on iteration, so there is no upfront cost associated with building
-/// or copying a VarStreamArray, no matter how large it may be.
-///
-/// You create a VarStreamArray by specifying a ValueType and an Extractor type.
-/// If you do not specify an Extractor type, you are expected to specialize
-/// VarStreamArrayExtractor<T> for your ValueType.
-///
-/// The default extractor type is stateless, but by specializing
-/// VarStreamArrayExtractor or defining your own custom extractor type and
-/// adding the appropriate ContextType typedef to the class, you can pass a
-/// context field during construction of the VarStreamArray that will be
-/// passed to each call to extract.
-///
-template <typename Value, typename Extractor, typename WrappedCtx>
-class VarStreamArrayBase {
- typedef VarStreamArrayBase<Value, Extractor, WrappedCtx> MyType;
-
-public:
- typedef VarStreamArrayIterator<MyType, Value, Extractor, WrappedCtx> Iterator;
- friend Iterator;
-
- VarStreamArrayBase() = default;
-
- VarStreamArrayBase(BinaryStreamRef Stream, const WrappedCtx &Ctx)
- : Stream(Stream), Ctx(Ctx) {}
-
- VarStreamArrayBase(const MyType &Other)
- : Stream(Other.Stream), Ctx(Other.Ctx) {}
-
- Iterator begin(bool *HadError = nullptr) const {
- if (empty())
- return end();
-
- return Iterator(*this, Ctx, Stream, HadError);
- }
-
- bool valid() const { return Stream.valid(); }
-
- Iterator end() const { return Iterator(Ctx); }
-
- bool empty() const { return Stream.getLength() == 0; }
-
- /// \brief given an offset into the array's underlying stream, return an
- /// iterator to the record at that offset. This is considered unsafe
- /// since the behavior is undefined if \p Offset does not refer to the
- /// beginning of a valid record.
- Iterator at(uint32_t Offset) const {
- return Iterator(*this, Ctx, Stream.drop_front(Offset), nullptr, Offset);
- }
-
- BinaryStreamRef getUnderlyingStream() const { return Stream; }
-
-private:
- BinaryStreamRef Stream;
- WrappedCtx Ctx;
-};
-
-template <typename Value, typename Extractor, typename Context>
-class VarStreamArrayImpl
- : public VarStreamArrayBase<Value, Extractor,
- ContextWrapper<Value, Context>> {
- typedef ContextWrapper<Value, Context> WrappedContext;
- typedef VarStreamArrayImpl<Value, Extractor, Context> MyType;
- typedef VarStreamArrayBase<Value, Extractor, WrappedContext> BaseType;
-
-public:
- typedef Context ContextType;
-
- VarStreamArrayImpl() = default;
- VarStreamArrayImpl(BinaryStreamRef Stream, Context &&Ctx)
- : BaseType(Stream, WrappedContext(std::forward<Context>(Ctx))) {}
-};
-
-template <typename Value, typename Extractor>
-class VarStreamArrayImpl<Value, Extractor, void>
- : public VarStreamArrayBase<Value, Extractor, ContextWrapper<Value, void>> {
- typedef ContextWrapper<Value, void> WrappedContext;
- typedef VarStreamArrayImpl<Value, Extractor, void> MyType;
- typedef VarStreamArrayBase<Value, Extractor, WrappedContext> BaseType;
-
-public:
- VarStreamArrayImpl() = default;
- VarStreamArrayImpl(BinaryStreamRef Stream)
- : BaseType(Stream, WrappedContext()) {}
-};
-
-template <typename Value, typename Extractor = VarStreamArrayExtractor<Value>>
-using VarStreamArray =
- VarStreamArrayImpl<Value, Extractor, typename Extractor::ContextType>;
-
template <typename T> class FixedStreamArrayIterator;
/// FixedStreamArray is similar to VarStreamArray, except with each record
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