SBE.h

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#pragma once
/*
* Copyright Onix Solutions Limited [OnixS]. All rights reserved.
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* and international copyright treaties.
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* Access to and use of the software is governed by the terms of the applicable ONIXS Software
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*
* Except as otherwise granted within the terms of the Agreement, copying or reproduction of any part
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*
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#include <string>
#include <vector>
#include <map>

#include <OnixS/FIXEngine/ABI.h>
#include <OnixS/FIXEngine/Compiler.h>
#include <OnixS/FIXEngine/FIX/Tag.h>
#include <OnixS/FIXEngine/FIX/ProtocolVersion.h>
#include <OnixS/FIXEngine/FIX/SbeCustomization.h>

namespace OnixS {
namespace FIX {
ONIXS_FIXENGINE_API_DECL(class, Message);
ONIXS_FIXENGINE_API_DECL(class, Dictionary);

namespace SBE {
/// Encodes FIX messages into the SBE representation.
class ONIXS_FIXENGINE_API Encoder
{
public:
    /// Creates a FIX to SBE Encoder.
    ///
    /// @param xmlTemplates XML-based SBE templates.
    /// @param customCoders The custom coders library.
    Encoder(const std::string & xmlTemplates, ISbeCustomCoderLibrary *customCoders = ONIXS_FIXENGINE_NULLPTR);

    /// Destructor.
    ~Encoder(void);

    /// Encodes the given FIX message into a SBE stream.
    ///
    /// @param[in] fixMessage The source FIX message to be encoded.
    /// @param[in] templateID the SBE Template Identifier which uniquely describes the encoding/decoding rules.
    /// @param[in] version The version of the template.
    /// @param[in] buffer The supplied buffer that will contain the SBE stream chunk.
    /// @param[in] bufferSize The size of the supplied buffer.
    /// @param[out] rootBlockLength The size of the root block, used for the encoded message.
    ///
    /// @return The size of the entire encoded SBE message.
    size_t encode(const OnixS::FIX::Message & fixMessage, int templateID, int version,
                  unsigned char * buffer, size_t bufferSize, size_t * rootBlockLength) const;

    /// Encodes the given FIX message into a SBE stream and prepends the message header.
    ///
    /// @param[in] fixMessage The source FIX message to be encoded.
    /// @param[in] templateID The SBE Template Identifier which uniquely describes the encoding/decoding rules.
    /// @param[in] version The version of the template.
    /// @param[in] buffer The supplied buffer that will contain the SBE stream chunk.
    /// @param[in] bufferSize The size of the supplied buffer.
    /// @param[out] rootBlockLength The size of the root block, used for the encoded message.
    ///
    /// @return The size of the entire encoded SBE message.
    size_t encodeWithHeader(const OnixS::FIX::Message& fixMessage, int templateID, int version,
        unsigned char* buffer, size_t bufferSize, size_t* rootBlockLength) const;

    /// The maximum known version of the SBE schema.
    unsigned schemaVersion() const;

    /// The schema identifier.
    unsigned schemaId() const;

    /// The semantic version of the SBE schema.
    std::string schemaSemanticVersion() const;

    /// The name of the encoding type of the message header, which is
    /// the same for all messages in a schema.
    std::string schemaHeaderType() const;
private:
    Encoder(const Encoder &);
    Encoder & operator = (const Encoder &);

    struct Impl;
    Impl * impl_;
};

/// Performs SBE to FIX decoding.
class ONIXS_FIXENGINE_API Decoder
{
public:
    /// Creates a SBE to FIX Decoder.
    ///
    /// @param xmlTemplates XML-based SBE templates.
    /// @param fixDictionary The customized FIX dictionary used for the decoded message.
    /// @param customCoders The custom coders library.
    Decoder(const std::string & xmlTemplates, const OnixS::FIX::Dictionary & fixDictionary, ISbeCustomCoderLibrary* customCoders = ONIXS_FIXENGINE_NULLPTR);

    /// Creates a SBE to FIX Decoder for the FIX dictionary-independent mode.
    /// The generic FIX dictionary is created by the provided SBE-template content, uses the FIX 4.0 as a base FIX dictionary and has a generic name.
    ///
    /// @param xmlTemplates XML-based SBE templates.
    /// @param customCoders The custom coders library.
    Decoder(const std::string & xmlTemplates, ISbeCustomCoderLibrary* customCoders = ONIXS_FIXENGINE_NULLPTR);

    /// Creates a SBE to FIX Decoder for the FIX dictionary-independent mode.
    /// The generic FIX dictionary is created by the provided SBE-template content, uses the specified FIX dictionary as a base and has a generic name.
    ///
    /// @param baseVersion The version of the FIX protocol which the dictionary becomes a base for the newly generated FIX dictionary.
    /// @param xmlTemplates XML-based SBE templates used to generate the FIX dictionary. This FIX dictionary takes a generic identifier generated on a base of the XML content and @c baseVersion
    /// @param customCoders The custom coders library.
    Decoder(ProtocolVersion::Enum baseVersion, const std::string & xmlTemplates, ISbeCustomCoderLibrary* customCoders = ONIXS_FIXENGINE_NULLPTR);

    /// The destructor.
    ~Decoder();

    /// Decodes the given SBE stream chunk into the corresponding FIX Message.
    ///
    /// @param[in] templateId The identifier of the SBE template, used to decode the input data.
    /// @param[in] version The version of the SBE schema, used to decode the input data.
    /// @param[in] rootBlockLength The length of the root block. This value should be extracted from the message preamble, or from other source.
    /// @param[in] buffer The buffer that contains the SBE stream chunk to be decoded.
    /// @param[in] bufferSize The size of the buffer.
    /// @param[out] numberOfDecodedBytes The number of bytes that contains the encoded FIX Message.
    ///
    /// @warning The returned message is 'owned' by the Decoder.
    /// @warning The previously decoded message is freed by the Decoder when this method is called again.
    ///
    /// @throw An exception if the message cannot be decoded.
    ///
    /// @return The decoded FIX message.
    const OnixS::FIX::Message & decode(int templateId, int version, size_t rootBlockLength,
                                       const unsigned char * buffer, size_t bufferSize, size_t * numberOfDecodedBytes = ONIXS_FIXENGINE_NULLPTR) const;

    /// Decodes the given SBE stream chunk into the corresponding FIX Message using the message header.
    ///
    /// This method decodes the given SBE stream chunk using the message header decoder that was built on a base of the SBE template.
    ///
    /// @param[in] buffer The buffer that contains the SBE stream chunk to be decoded.
    /// @param[in] bufferSize The size of the buffer.
    /// @param[out] numberOfDecodedBytes The number of bytes that contained the encoded FIX Message.
    /// @param[out] templateId The identifier of the SBE template, that was used to decode the input data.
    /// @param[out] version The version of the SBE schema, that was used to decode the input data.
    ///
    /// @warning The returned message is 'owned' by the Decoder.
    /// @warning The previously decoded message is freed by the Decoder when this method is called again.
    ///
    /// @throw An exception if the message cannot be decoded.
    ///
    /// @return The decoded FIX message.
    const OnixS::FIX::Message& decode(const unsigned char* buffer, size_t bufferSize, size_t* numberOfDecodedBytes = ONIXS_FIXENGINE_NULLPTR,
                                      int *templateId = ONIXS_FIXENGINE_NULLPTR, int *version = ONIXS_FIXENGINE_NULLPTR) const;


    /// Tries to decode the given SBE stream buffer into the corresponding FIX Message.
    ///
    /// @param[in] templateId The identifier of the SBE template, used to decode the input data.
    /// @param[in] version The version of the SBE schema, used to decode the input data.
    /// @param[in] rootBlockLength The length of the root block. This value should be extracted from the message preamble, or from other source.
    /// @param[in] buffer The SBE stream chunk to be decoded.
    /// @param[in] offset The index in the buffer at which decoding begins.
    /// @param[in] count The number of bytes to analyze during the decoding.
    /// @param[out] message The pointer to the decoded FIX Message.
    /// @param[out] numberOfDecodedBytes The number of bytes that contained the encoded FIX Message.
    ///
    /// @warning the message should point to an existing object. This object is not owned by the Decoder and should be managed by a user.
    ///
    /// @throw An exception if the decoding error is detected.
    ///
    /// @return 'true' if the given bytes could be decoded into a FIX message, otherwise - 'false'.
    bool tryDecode(int templateId, int version, size_t rootBlockLength,
                   const unsigned char * buffer, size_t offset, size_t count, OnixS::FIX::Message * message,
                   size_t * numberOfDecodedBytes) const;

    /// The FIX dictionary used by the decoder instance.
    ///
    /// @return The FIX dictionary currently used by the decoder instance. If the decoder was initialized with the FIX dictionary-independent mode, the method returns
    /// a reference to the internally generated FIX dictionary.
    OnixS::FIX::Dictionary fixDictionary() const;

    /// Manage the maximum number of repeating groups, allowed for decoded messages.
    ///
    /// This parameter is used during the decoding and is useful to detect a broken data, which, in particular cases,
    /// can 'need' to allocate an unexpectedly huge number of entries (for an instance - billions of entries,
    /// while normally there are just a few ones). This situation results in a memory exhausting and (often)
    /// significantly decrease the overall system performance.
    ///
    /// To prevent the memory exhausting and negative consequences of that, this parameter should be configured with the value,
    /// which is greater then maximum possible number of entries in the valid input data, but less then the maximum integer value (default one).
    /// In a lot of real cases value of 10000 is good enough to detect broken data without a memory overloading.
    ///
    /// Default is the maximum positive value for the @c int type.
    ///
    /// @param value The number of repeating groups, allowed for decoded messages.
    void maximumNumberOfRepeatingGroupEntries(int value);

    /// The maximum number of repeating groups, allowed for decoded messages.
    ///
    /// @return The current number of repeating groups, allowed for decoded messages. The default value is the maximum positive value for the @c int type.
    int maximumNumberOfRepeatingGroupEntries() const;

    /// Generates the FIX dictionary XML.
    ///
    /// @param[in] sbeTemplateXml The XML content of the SBE template (the same as used to initialize the Decoder).
    ///
    static Dictionary generateFixDictionary(const std::string & sbeTemplateXml);

    /// Generates the FIX dictionary XML.
    ///
    /// @param[in] sbeTemplateXml The XML content of the SBE template (the same as used to initialize the Decoder).
    /// @param[in] baseVersion The version of the FIX protocol which the dictionary becomes a base for the newly generated FIX dictionary.
    static Dictionary generateFixDictionary(ProtocolVersion::Enum baseVersion,
                                            const std::string & sbeTemplateXml);

    /// The maximum known version of the SBE schema.
    unsigned schemaVersion() const;

    /// The schema identifier.
    unsigned schemaId() const;

    /// The semantic version of the SBE schema.
    std::string schemaSemanticVersion() const;

    /// The name of the encoding type of the message header, which is
    /// the same for all messages in a schema.
    std::string schemaHeaderType() const;
private:
    friend ONIXS_FIXENGINE_API_DECL(class, OnixS::FIX::Dictionary);

    Decoder(const Decoder &);
    Decoder & operator = (const Decoder &);

    struct Impl;
    Impl * impl_;
};

}
}
}