PacketEntityUtils.h

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#pragma once
#include "Packet.h"
#include "PacketPayloadParser.h"
#include "catapult/model/EntityRange.h"
 
namespace catapult { namespace ionet {
 
    inline size_t CalculatePacketDataSize(const Packet& packet) {
        constexpr auto Min_Size = sizeof(PacketHeader);
        if (packet.Size <= Min_Size) {
            if (packet.Size < Min_Size)
                CATAPULT_LOG(warning) << "packet size (" << packet.Size << ") must be at least " << Min_Size;
 
            return 0;
        }
 
        return packet.Size - Min_Size;
    }
 
    template<typename TEntity>
    bool IsSizeValid(const TEntity& entity) {
        return TEntity::CalculateRealSize(entity) == entity.Size;
    }
 
    template<typename TEntity, typename TIsValidPredicate>
    model::EntityRange<TEntity> ExtractEntitiesFromPacket(const Packet& packet, TIsValidPredicate isValid) {
        auto dataSize = CalculatePacketDataSize(packet);
        auto offsets = ExtractEntityOffsets<TEntity>({ packet.Data(), dataSize }, isValid);
        return offsets.empty()
                ? model::EntityRange<TEntity>()
                : model::EntityRange<TEntity>::CopyVariable(packet.Data(), dataSize, offsets);
    }
 
    template<typename TEntity, typename TIsValidPredicate>
    std::unique_ptr<TEntity> ExtractEntityFromPacket(const Packet& packet, TIsValidPredicate isValid) {
        auto dataSize = CalculatePacketDataSize(packet);
        if (!ContainsSingleEntity<TEntity>({ packet.Data(), dataSize }, isValid))
            return nullptr;
 
        auto pEntity = utils::MakeUniqueWithSize<TEntity>(dataSize);
        std::memcpy(static_cast<void*>(pEntity.get()), packet.Data(), dataSize);
        return pEntity;
    }
 
    template<typename TStructure>
    model::EntityRange<TStructure> ExtractFixedSizeStructuresFromPacket(const Packet& packet) {
        auto dataSize = CalculatePacketDataSize(packet);
        auto numStructures = CountFixedSizeStructures<TStructure>({ packet.Data(), dataSize });
        return 0 == numStructures
                ? model::EntityRange<TStructure>()
                : model::EntityRange<TStructure>::CopyFixed(packet.Data(), numStructures);
    }
}}