include/Ice/OutputStream.h

//
// Copyright (c) ZeroC, Inc. All rights reserved.
//

#ifndef ICE_OUTPUT_STREAM_H
#define ICE_OUTPUT_STREAM_H

#include <Ice/CommunicatorF.h>
#include <Ice/InstanceF.h>
#include <Ice/Object.h>
#include <Ice/ValueF.h>
#include <Ice/ProxyF.h>
#include <Ice/Buffer.h>
#include <Ice/Protocol.h>
#include <Ice/SlicedDataF.h>
#include <Ice/StreamHelpers.h>

namespace Ice
{

class UserException;

/**
 * Interface for output streams used to create a sequence of bytes from Slice types.
 * \headerfile Ice/Ice.h
 */
class ICE_API OutputStream : public IceInternal::Buffer
{
public:

    typedef size_t size_type;

    /**
     * Constructs an OutputStream using the latest encoding version, the default format for
     * class encoding, and the process string converters. You can supply a communicator later
     * by calling initialize().
     */
    OutputStream();

    /**
     * Constructs a stream using the communicator's default encoding version.
     * @param communicator The communicator to use for marshaling tasks.
     */
    OutputStream(const CommunicatorPtr& communicator);

    /**
     * Constructs a stream using the given communicator and encoding version.
     * @param communicator The communicator to use for marshaling tasks.
     * @param version The encoding version used to encode the data.
     */
    OutputStream(const CommunicatorPtr& communicator, const EncodingVersion& version);

    /**
     * Constructs a stream using the given communicator and encoding version.
     * @param communicator The communicator to use for marshaling tasks.
     * @param version The encoding version used to encode the data.
     * @param bytes Application-supplied memory that the stream uses as its initial marshaling buffer. The
     * stream will reallocate if the size of the marshaled data exceeds the application's buffer.
     */
    OutputStream(const CommunicatorPtr& communicator, const EncodingVersion& version,
                 const std::pair<const Byte*, const Byte*>& bytes);

    ~OutputStream()
    {
        // Inlined for performance reasons.

        if(_currentEncaps != &_preAllocatedEncaps)
        {
            clear(); // Not inlined.
        }
    }

    /**
     * Initializes the stream to use the communicator's default encoding version, class
     * encoding format and string converters. Use this method if you originally constructed
     * the stream without a communicator.
     * @param communicator The communicator to use for marshaling tasks.
     */
    void initialize(const CommunicatorPtr& communicator);

    /**
     * Initializes the stream to use the given encoding version and the communicator's
     * default class encoding format and string converters. Use this method if you
     * originally constructed the stream without a communicator.
     * @param communicator The communicator to use for marshaling tasks.
     * @param version The encoding version used to encode the data.
     */
    void initialize(const CommunicatorPtr& communicator, const EncodingVersion& version);

    /**
     * Releases any data retained by encapsulations.
     */
    void clear();

    /// \cond INTERNAL
    //
    // Must return Instance*, because we don't hold an InstancePtr for
    // optimization reasons (see comments below).
    //
    IceInternal::Instance* instance() const { return _instance; } // Inlined for performance reasons.
    /// \endcond

    /**
     * Sets the class encoding format.
     * @param format The encoding format.
     */
    void setFormat(FormatType format);

    /**
     * Obtains the closure data associated with this stream.
     * @return The data as a void pointer.
     */
    void* getClosure() const;

    /**
     * Associates closure data with this stream.
     * @param p The data as a void pointer.
     * @return The previous closure data, or nil.
     */
    void* setClosure(void* p);

    /**
     * Swaps the contents of one stream with another.
     *
     * @param other The other stream.
     */
    void swap(OutputStream& other);

    /// \cond INTERNAL
    void resetEncapsulation();
    /// \endcond

    /**
     * Resizes the stream to a new size.
     *
     * @param sz The new size.
     */
    void resize(Container::size_type sz)
    {
        b.resize(sz);
    }

    /**
     * Marks the start of a class instance.
     * @param data Contains the marshaled form of unknown slices from this instance. If not nil,
     * these slices will be marshaled with the instance.
     */
    void startValue(const SlicedDataPtr& data)
    {
        assert(_currentEncaps && _currentEncaps->encoder);
        _currentEncaps->encoder->startInstance(ValueSlice, data);
    }

    /**
     * Marks the end of a class instance.
     */
    void endValue()
    {
        assert(_currentEncaps && _currentEncaps->encoder);
        _currentEncaps->encoder->endInstance();
    }

    /**
     * Marks the start of an exception instance.
     * @param data Contains the marshaled form of unknown slices from this instance. If not nil,
     * these slices will be marshaled with the instance.
     */
    void startException(const SlicedDataPtr& data)
    {
        assert(_currentEncaps && _currentEncaps->encoder);
        _currentEncaps->encoder->startInstance(ExceptionSlice, data);
    }

    /**
     * Marks the end of an exception instance.
     */
    void endException()
    {
        assert(_currentEncaps && _currentEncaps->encoder);
        _currentEncaps->encoder->endInstance();
    }

    /**
     * Writes the start of an encapsulation using the default encoding version and
     * class encoding format.
     */
    void startEncapsulation();

    /**
     * Writes the start of an encapsulation using the given encoding version and
     * class encoding format.
     * @param encoding The encoding version to use for the encapsulation.
     * @param format The class format to use for the encapsulation.
     */
    void startEncapsulation(const EncodingVersion& encoding, FormatType format)
    {
        IceInternal::checkSupportedEncoding(encoding);

        Encaps* oldEncaps = _currentEncaps;
        if(!oldEncaps) // First allocated encaps?
        {
            _currentEncaps = &_preAllocatedEncaps;
        }
        else
        {
            _currentEncaps = new Encaps();
            _currentEncaps->previous = oldEncaps;
        }
        _currentEncaps->format = format;
        _currentEncaps->encoding = encoding;
        _currentEncaps->start = b.size();

        write(Int(0)); // Placeholder for the encapsulation length.
        write(_currentEncaps->encoding);
    }

    /**
     * Ends the current encapsulation.
     */
    void endEncapsulation()
    {
        assert(_currentEncaps);

        // Size includes size and version.
        const Int sz = static_cast<Int>(b.size() - _currentEncaps->start);
        write(sz, &(*(b.begin() + _currentEncaps->start)));

        Encaps* oldEncaps = _currentEncaps;
        _currentEncaps = _currentEncaps->previous;
        if(oldEncaps == &_preAllocatedEncaps)
        {
            oldEncaps->reset();
        }
        else
        {
            delete oldEncaps;
        }
    }

    /**
     * Writes an empty encapsulation using the given encoding version.
     * @param encoding The encoding version to use for the encapsulation.
     */
    void writeEmptyEncapsulation(const EncodingVersion& encoding)
    {
        IceInternal::checkSupportedEncoding(encoding);
        write(Int(6)); // Size
        write(encoding);
    }

    /**
     * Copies the marshaled form of an encapsulation to the buffer.
     * @param v The start of the buffer.
     * @param sz The number of bytes to copy.
     */
    void writeEncapsulation(const Byte* v, Int sz)
    {
        if(sz < 6)
        {
            throwEncapsulationException(__FILE__, __LINE__);
        }

        Container::size_type position = b.size();
        resize(position + sz);
        memcpy(&b[position], &v[0], sz);
    }

    /**
     * Determines the current encoding version.
     *
     * @return The encoding version.
     */
    const EncodingVersion& getEncoding() const
    {
        return _currentEncaps ? _currentEncaps->encoding : _encoding;
    }

    /**
     * Writes the start of a value or exception slice.
     *
     * @param typeId The Slice type ID for this slice.
     * @param compactId The compact ID corresponding to the type, or -1 if no compact ID is used.
     * @param last True if this is the last slice, false otherwise.
     */
    void startSlice(const std::string& typeId, int compactId, bool last)
    {
        assert(_currentEncaps && _currentEncaps->encoder);
        _currentEncaps->encoder->startSlice(typeId, compactId, last);
    }

    /**
     * Marks the end of a value or exception slice.
     */
    void endSlice()
    {
        assert(_currentEncaps && _currentEncaps->encoder);
        _currentEncaps->encoder->endSlice();
    }

    /**
     * Encodes the state of class instances whose insertion was delayed during a previous
     * call to write. This member function must only be called once. For backward
     * compatibility with encoding version 1.0, this function must only be called when
     * non-optional data members or parameters use class types.
     */
    void writePendingValues();

    /**
     * Writes a size value.
     * @param v A non-negative integer.
     */
    void writeSize(Int v) // Inlined for performance reasons.
    {
        assert(v >= 0);
        if(v > 254)
        {
            write(Byte(255));
            write(v);
        }
        else
        {
            write(static_cast<Byte>(v));
        }
    }

    /**
     * Replaces a size value at the given destination in the stream. This function
     * does not change the stream's current position.
     * @param v A non-negative integer representing the size.
     * @param dest The buffer destination for the size.
     */
    void rewriteSize(Int v, Container::iterator dest)
    {
        assert(v >= 0);
        if(v > 254)
        {
            *dest++ = Byte(255);
            write(v, dest);
        }
        else
        {
            *dest = static_cast<Byte>(v);
        }
    }

    /**
     * Writes a placeholder value for the size and returns the starting position of the
     * size value; after writing the data, call endSize to patch the placeholder with
     * the actual size at the given position.
     * @return The starting position of the size value.
     */
    size_type startSize()
    {
        size_type position = b.size();
        write(Int(0));
        return position;
    }

    /**
     * Updates the size value at the given position to contain a size based on the
     * stream's current position.
     * @param position The starting position of the size value as returned by startSize.
     */
    void endSize(size_type position)
    {
        rewrite(static_cast<Int>(b.size() - position) - 4, position);
    }

    /**
     * Copies the specified blob of bytes to the stream without modification.
     * @param v The bytes to be copied.
     */
    void writeBlob(const std::vector<Byte>& v);

    /**
     * Copies the specified blob of bytes to the stream without modification.
     * @param v The start of the buffer to be copied.
     * @param sz The number of bytes to be copied.
     */
    void writeBlob(const Byte* v, Container::size_type sz)
    {
        if(sz > 0)
        {
            Container::size_type position = b.size();
            resize(position + sz);
            memcpy(&b[position], &v[0], sz);
        }
    }

    /**
     * Writes a data value to the stream.
     * @param v The data value to be written.
     */
    template<typename T> void write(const T& v)
    {
        StreamHelper<T, StreamableTraits<T>::helper>::write(this, v);
    }

    /**
     * Writes an optional data value to the stream.
     * @param tag The tag ID.
     * @param v The data value to be written (if any).
     */
    template<typename T> void write(Int tag, const IceUtil::Optional<T>& v)
    {
        if(!v)
        {
            return; // Optional not set
        }

        if(writeOptional(tag, StreamOptionalHelper<T,
                                              StreamableTraits<T>::helper,
                                              StreamableTraits<T>::fixedLength>::optionalFormat))
        {
            StreamOptionalHelper<T,
                                 StreamableTraits<T>::helper,
                                 StreamableTraits<T>::fixedLength>::write(this, *v);
        }
    }

    /**
     * Writes a sequence of data values to the stream.
     * @param v The sequence to be written.
     */
    template<typename T> void write(const std::vector<T>& v)
    {
        if(v.empty())
        {
            writeSize(0);
        }
        else
        {
            write(&v[0], &v[0] + v.size());
        }
    }

    /**
     * Writes a sequence of data values to the stream.
     * @param begin The beginning of the sequence.
     * @param end The end of the sequence.
     */
    template<typename T> void write(const T* begin, const T* end)
    {
        writeSize(static_cast<Int>(end - begin));
        for(const T* p = begin; p != end; ++p)
        {
            write(*p);
        }
    }

#ifdef ICE_CPP11_MAPPING

    /**
     * Writes a list of mandatory data values.
     */
    template<typename T> void writeAll(const T& v)
    {
        write(v);
    }

    /**
     * Writes a list of mandatory data values.
     */
    template<typename T, typename... Te> void writeAll(const T& v, const Te&... ve)
    {
        write(v);
        writeAll(ve...);
    }

    /**
     * Writes a list of mandatory data values.
     */
    template<size_t I = 0, typename... Te>
    typename std::enable_if<I == sizeof...(Te), void>::type
    writeAll(std::tuple<Te...>)
    {
        // Do nothing. Either tuple is empty or we are at the end.
    }

    /**
     * Writes a list of mandatory data values.
     */
    template<size_t I = 0, typename... Te>
    typename std::enable_if<I < sizeof...(Te), void>::type
    writeAll(std::tuple<Te...> tuple)
    {
        write(std::get<I>(tuple));
        writeAll<I + 1, Te...>(tuple);
    }

    /**
     * Writes a list of optional data values.
     */
    template<typename T>
    void writeAll(std::initializer_list<int> tags, const IceUtil::Optional<T>& v)
    {
        write(*(tags.begin() + tags.size() - 1), v);
    }

    /**
     * Writes a list of optional data values.
     */
    template<typename T, typename... Te>
    void writeAll(std::initializer_list<int> tags, const IceUtil::Optional<T>& v, const IceUtil::Optional<Te>&... ve)
    {
        size_t index = tags.size() - sizeof...(ve) - 1;
        write(*(tags.begin() + index), v);
        writeAll(tags, ve...);
    }

#endif

    /**
     * Writes the tag and format of an optional value.
     * @param tag The optional tag ID.
     * @param format The optional format.
     * @return True if the current encoding version supports optional values, false otherwise.
     * If true, the data associated with the optional value must be written next.
     */
    bool writeOptional(Int tag, OptionalFormat format)
    {
        assert(_currentEncaps);
        if(_currentEncaps->encoder)
        {
            return _currentEncaps->encoder->writeOptional(tag, format);
        }
        else
        {
            return writeOptImpl(tag, format);
        }
    }

    /**
     * Writes a byte to the stream.
     * @param v The byte to write.
     */
    void write(Byte v)
    {
        b.push_back(v);
    }

    /**
     * Writes a byte sequence to the stream.
     * @param start The beginning of the sequence.
     * @param end The end of the sequence.
     */
    void write(const Byte* start, const Byte* end);

    /**
     * Writes a boolean to the stream.
     * @param v The boolean to write.
     */
    void write(bool v)
    {
        b.push_back(static_cast<Byte>(v));
    }

    /**
     * Writes a byte sequence to the stream.
     * @param v The sequence to be written.
     */
    void write(const std::vector<bool>& v);

    /**
     * Writes a byte sequence to the stream.
     * @param begin The beginning of the sequence.
     * @param end The end of the sequence.
     */
    void write(const bool* begin, const bool* end);

    /**
     * Writes a short to the stream.
     * @param v The short to write.
     */
    void write(Short v);

    /**
     * Writes a short sequence to the stream.
     * @param begin The beginning of the sequence.
     * @param end The end of the sequence.
     */
    void write(const Short* begin, const Short* end);

    /**
     * Writes an int to the stream.
     * @param v The int to write.
     */
    void write(Int v) // Inlined for performance reasons.
    {
        Container::size_type position = b.size();
        resize(position + sizeof(Int));
        write(v, &b[position]);
    }

    /**
     * Overwrites a 32-bit integer value at the given destination in the stream.
     * This function does not change the stream's current position.
     * @param v The integer value to be written.
     * @param dest The buffer destination for the integer value.
     */
    void write(Int v, Container::iterator dest)
    {
#ifdef ICE_BIG_ENDIAN
        const Byte* src = reinterpret_cast<const Byte*>(&v) + sizeof(Int) - 1;
        *dest++ = *src--;
        *dest++ = *src--;
        *dest++ = *src--;
        *dest = *src;
#else
        const Byte* src = reinterpret_cast<const Byte*>(&v);
        *dest++ = *src++;
        *dest++ = *src++;
        *dest++ = *src++;
        *dest = *src;
#endif
    }

    /**
     * Writes an int sequence to the stream.
     * @param begin The beginning of the sequence.
     * @param end The end of the sequence.
     */
    void write(const Int* begin, const Int* end);

    /**
     * Writes a long to the stream.
     * @param v The long to write.
     */
    void write(Long v);

    /**
     * Writes a long sequence to the stream.
     * @param begin The beginning of the sequence.
     * @param end The end of the sequence.
     */
    void write(const Long* begin, const Long* end);

    /**
     * Writes a float to the stream.
     * @param v The float to write.
     */
    void write(Float v);

    /**
     * Writes a float sequence to the stream.
     * @param begin The beginning of the sequence.
     * @param end The end of the sequence.
     */
    void write(const Float* begin, const Float* end);

    /**
     * Writes a double to the stream.
     * @param v The double to write.
     */
    void write(Double v);

    /**
     * Writes a double sequence to the stream.
     * @param begin The beginning of the sequence.
     * @param end The end of the sequence.
     */
    void write(const Double* begin, const Double* end);

    /**
     * Writes a string to the stream.
     * @param v The string to write.
     * @param convert Determines whether the string is processed by the narrow string converter,
     * if one has been configured. The default behavior is to convert the strings.
     */
    void write(const std::string& v, bool convert = true)
    {
        Int sz = static_cast<Int>(v.size());
        if(convert && sz > 0)
        {
            writeConverted(v.data(), static_cast<size_t>(sz));
        }
        else
        {
            writeSize(sz);
            if(sz > 0)
            {
                Container::size_type position = b.size();
                resize(position + sz);
                memcpy(&b[position], v.data(), sz);
            }
        }
    }

    /**
     * Writes a string to the stream.
     * @param vdata The string to write.
     * @param vsize The size of the string.
     * @param convert Determines whether the string is processed by the narrow string converter,
     * if one has been configured. The default behavior is to convert the strings.
     */
    void write(const char* vdata, size_t vsize, bool convert = true)
    {
        Int sz = static_cast<Int>(vsize);
        if(convert && sz > 0)
        {
            writeConverted(vdata, vsize);
        }
        else
        {
            writeSize(sz);
            if(sz > 0)
            {
                Container::size_type position = b.size();
                resize(position + sz);
                memcpy(&b[position], vdata, vsize);
            }
        }
    }

    /**
     * Writes a string to the stream.
     * @param vdata The null-terminated string to write.
     * @param convert Determines whether the string is processed by the narrow string converter,
     * if one has been configured. The default behavior is to convert the strings.
     */
    void write(const char* vdata, bool convert = true)
    {
        write(vdata, strlen(vdata), convert);
    }

    /**
     * Writes a string sequence to the stream.
     * @param begin The beginning of the sequence.
     * @param end The end of the sequence.
     * @param convert Determines whether the string is processed by the narrow string converter,
     * if one has been configured. The default behavior is to convert the strings.
     */
    void write(const std::string* begin, const std::string* end, bool convert = true);

    /**
     * Writes a wide string to the stream.
     * @param v The wide string to write.
     */
    void write(const std::wstring& v);

    /**
     * Writes a wide string sequence to the stream.
     * @param begin The beginning of the sequence.
     * @param end The end of the sequence.
     */
    void write(const std::wstring* begin, const std::wstring* end);

#ifdef ICE_CPP11_MAPPING
    /**
     * Writes a proxy to the stream.
     * @param v The proxy to be written.
     */
    void writeProxy(const ::std::shared_ptr<ObjectPrx>& v);

    /**
     * Writes a proxy to the stream.
     * @param v The proxy to be written.
     */
    template<typename T, typename ::std::enable_if<::std::is_base_of<ObjectPrx, T>::value>::type* = nullptr>
    void write(const ::std::shared_ptr<T>& v)
    {
        writeProxy(::std::static_pointer_cast<ObjectPrx>(v));
    }
#else
    /**
     * Writes a proxy to the stream.
     * @param v The proxy to be written.
     */
    void write(const ObjectPrx& v);

    /**
     * Writes a proxy to the stream.
     * @param v The proxy to be written.
     */
    template<typename T> void write(const IceInternal::ProxyHandle<T>& v)
    {
        write(ObjectPrx(upCast(v.get())));
    }
#endif

#ifdef ICE_CPP11_MAPPING // C++11 mapping
    /**
     * Writes a value instance to the stream.
     * @param v The value to be written.
     */
    template<typename T, typename ::std::enable_if<::std::is_base_of<Value, T>::value>::type* = nullptr>
    void write(const ::std::shared_ptr<T>& v)
    {
        initEncaps();
        _currentEncaps->encoder->write(v);
    }
#else // C++98 mapping
    /**
     * Writes a value instance to the stream.
     * @param v The value to be written.
     */
    void write(const ObjectPtr& v)
    {
        initEncaps();
        _currentEncaps->encoder->write(v);
    }

    /**
     * Writes a value instance to the stream.
     * @param v The value to be written.
     */
    template<typename T> void write(const IceInternal::Handle<T>& v)
    {
        write(ObjectPtr(upCast(v.get())));
    }
#endif

    /**
     * Writes an enumerator to the stream.
     * @param v The enumerator to be written.
     * @param maxValue The maximum value of all enumerators in this enumeration.
     */
    void writeEnum(Int v, Int maxValue);

    /**
     * Writes an exception to the stream.
     * @param v The exception to be written.
     */
    void writeException(const UserException& v);

    /**
     * Obtains the current position of the stream.
     * @return The current position.
     */
    size_type pos()
    {
        return b.size();
    }

    /**
     * Overwrite a 32-bit integer value at the given position in the stream.
     * This function does not change the stream's current position.
     * @param v The value to be written.
     * @param pos The buffer position for the value.
     */
    void rewrite(Int v, size_type pos)
    {
        write(v, b.begin() + pos);
    }

    /**
     * Indicates that marshaling is complete. This function must only be called once.
     * @param v Filled with a copy of the encoded data.
     */
    void finished(std::vector<Byte>& v);

    /**
     * Indicates that marshaling is complete. This function must only be called once.
     * @return A pair of pointers into the internal marshaling buffer. These pointers are
     * valid for the lifetime of the stream.
     */
    std::pair<const Byte*, const Byte*> finished();

    /// \cond INTERNAL
    OutputStream(IceInternal::Instance*, const EncodingVersion&);
    void initialize(IceInternal::Instance*, const EncodingVersion&);

    // Optionals
    bool writeOptImpl(Int, OptionalFormat);
    /// \endcond

private:

    //
    // String
    //
    void writeConverted(const char*, size_t);

    //
    // We can't throw this exception from inline functions from within
    // this file, because we cannot include the header with the
    // exceptions. Doing so would screw up the whole include file
    // ordering.
    //
    void throwEncapsulationException(const char*, int);

    //
    // Optimization. The instance may not be deleted while a
    // stack-allocated stream still holds it.
    //
    IceInternal::Instance* _instance;

    //
    // The public stream API needs to attach data to a stream.
    //
    void* _closure;

    class Encaps;
    enum SliceType { NoSlice, ValueSlice, ExceptionSlice };

    typedef std::vector<ValuePtr> ValueList;

    class ICE_API EncapsEncoder : private ::IceUtil::noncopyable
    {
    public:

        virtual ~EncapsEncoder();

        virtual void write(const ValuePtr&) = 0;
        virtual void write(const UserException&) = 0;

        virtual void startInstance(SliceType, const SlicedDataPtr&) = 0;
        virtual void endInstance() = 0;
        virtual void startSlice(const std::string&, int, bool) = 0;
        virtual void endSlice() = 0;

        virtual bool writeOptional(Int, OptionalFormat)
        {
            return false;
        }

        virtual void writePendingValues()
        {
        }

    protected:

        EncapsEncoder(OutputStream* stream, Encaps* encaps) : _stream(stream), _encaps(encaps), _typeIdIndex(0)
        {
        }

        Int registerTypeId(const std::string&);

        OutputStream* _stream;
        Encaps* _encaps;

        typedef std::map<ValuePtr, Int> PtrToIndexMap;
        typedef std::map<std::string, Int> TypeIdMap;

        // Encapsulation attributes for value marshaling.
        PtrToIndexMap _marshaledMap;

    private:

        // Encapsulation attributes for value marshaling.
        TypeIdMap _typeIdMap;
        Int _typeIdIndex;
    };

    class ICE_API EncapsEncoder10 : public EncapsEncoder
    {
    public:

        EncapsEncoder10(OutputStream* stream, Encaps* encaps) :
            EncapsEncoder(stream, encaps), _sliceType(NoSlice), _valueIdIndex(0)
        {
        }

        virtual void write(const ValuePtr&);
        virtual void write(const UserException&);

        virtual void startInstance(SliceType, const SlicedDataPtr&);
        virtual void endInstance();
        virtual void startSlice(const std::string&, int, bool);
        virtual void endSlice();

        virtual void writePendingValues();

    private:

        Int registerValue(const ValuePtr&);

        // Instance attributes
        SliceType _sliceType;

        // Slice attributes
        Container::size_type _writeSlice; // Position of the slice data members

        // Encapsulation attributes for value marshaling.
        Int _valueIdIndex;
        PtrToIndexMap _toBeMarshaledMap;
    };

    class ICE_API EncapsEncoder11 : public EncapsEncoder
    {
    public:

        EncapsEncoder11(OutputStream* stream, Encaps* encaps) :
            EncapsEncoder(stream, encaps), _preAllocatedInstanceData(0), _current(0), _valueIdIndex(1)
        {
        }

        virtual void write(const ValuePtr&);
        virtual void write(const UserException&);

        virtual void startInstance(SliceType, const SlicedDataPtr&);
        virtual void endInstance();
        virtual void startSlice(const std::string&, int, bool);
        virtual void endSlice();

        virtual bool writeOptional(Int, OptionalFormat);

    private:

        void writeSlicedData(const SlicedDataPtr&);
        void writeInstance(const ValuePtr&);

        struct InstanceData
        {
            InstanceData(InstanceData* p) : previous(p), next(0)
            {
                if(previous)
                {
                    previous->next = this;
                }
            }

            ~InstanceData()
            {
                if(next)
                {
                    delete next;
                }
            }

            // Instance attributes
            SliceType sliceType;
            bool firstSlice;

            // Slice attributes
            Byte sliceFlags;
            Container::size_type writeSlice;    // Position of the slice data members
            Container::size_type sliceFlagsPos; // Position of the slice flags
            PtrToIndexMap indirectionMap;
            ValueList indirectionTable;

            InstanceData* previous;
            InstanceData* next;
        };
        InstanceData _preAllocatedInstanceData;
        InstanceData* _current;

        Int _valueIdIndex; // The ID of the next value to marhsal
    };

    class Encaps : private ::IceUtil::noncopyable
    {

    public:

        Encaps() : format(ICE_ENUM(FormatType, DefaultFormat)), encoder(0), previous(0)
        {
            // Inlined for performance reasons.
        }
        ~Encaps()
        {
            // Inlined for performance reasons.
            delete encoder;
        }
        void reset()
        {
            // Inlined for performance reasons.
            delete encoder;
            encoder = 0;

            previous = 0;
        }

        Container::size_type start;
        EncodingVersion encoding;
        FormatType format;

        EncapsEncoder* encoder;

        Encaps* previous;
    };

    //
    // The encoding version to use when there's no encapsulation to
    // read from or write to. This is for example used to read message
    // headers or when the user is using the streaming API with no
    // encapsulation.
    //
    EncodingVersion _encoding;

    FormatType _format;

    Encaps* _currentEncaps;

    void initEncaps();

    Encaps _preAllocatedEncaps;
};

} // End namespace Ice

#endif