fsfw/serialize/SerializeAdapter.h

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2020-08-18 13:09:15 +02:00
#ifndef SERIALIZEADAPTER_H_
#define SERIALIZEADAPTER_H_
#include "../container/IsDerivedFrom.h"
#include "../returnvalues/HasReturnvaluesIF.h"
#include "../serialize/EndianConverter.h"
#include "../serialize/SerializeIF.h"
#include <type_traits>
/**
* @brief These adapters provides an interface to use the SerializeIF functions
* with arbitrary template objects to facilitate and simplify the
* serialization of classes with different multiple different data types
* into buffers and vice-versa.
* @details
*
* A report class is converted into a TM buffer. The report class implements a
* serialize functions and calls the AutoSerializeAdapter::serialize function
* repeatedly on all object data fields. The getSerializedSize function is
* implemented by calling the AutoSerializeAdapter::getSerializedSize function
* repeatedly on all data fields.
*
* The AutoSerializeAdapter functions can also be used as an alternative to
* memcpy to retrieve data out of a buffer directly into a class variable
* with data type T while being able to specify endianness. The boolean
* bigEndian specifies whether an endian swap is performed on the data before
* serialization or deserialization.
*
* There are three ways to retrieve data out of a buffer to be used in the FSFW
* to use regular aligned (big endian) data. Examples:
*
* 1. Use the AutoSerializeAdapter::deSerialize function
* The pointer *buffer will be incremented automatically by the typeSize
* of the object, so this function can be called on &buffer repeatedly
* without adjusting pointer position. Set bigEndian parameter to true
* to perform endian swapping, if necessary
* @code
* uint16_t data;
* int32_t dataLen = sizeof(data);
* ReturnValue_t result =
* AutoSerializeAdapter::deSerialize(&data,&buffer,&dataLen,true);
* @endcode
*
* 2. Perform a bitshift operation. Watch for for endianness:
* @code
* uint16_t data;
* data = buffer[targetByte1] << 8 | buffer[targetByte2];
* data = EndianSwapper::swap(data); //optional, or swap order above
* @endcode
*
* 3. memcpy or std::copy can also be used, but watch out if system
* endianness is different from required data endianness.
* Perform endian-swapping if necessary.
* @code
* uint16_t data;
* memcpy(&data,buffer + positionOfTargetByte1,sizeof(data));
* data = EndianSwapper::swap(data); //optional
* @endcode
*
* When serializing for downlink, the packets are generally serialized assuming
* big endian data format like seen in TmPacketStored.cpp for example.
*
* @ingroup serialize
*/
class SerializeAdapter {
public:
template<typename T>
static ReturnValue_t serialize(const T *object, uint8_t **buffer,
size_t *size, size_t maxSize, SerializeIF::Endianness streamEndianness) {
InternalSerializeAdapter<T, IsDerivedFrom<T, SerializeIF>::Is> adapter;
return adapter.serialize(object, buffer, size, maxSize,
streamEndianness);
}
template<typename T>
static uint32_t getSerializedSize(const T *object) {
InternalSerializeAdapter<T, IsDerivedFrom<T, SerializeIF>::Is> adapter;
return adapter.getSerializedSize(object);
}
template<typename T>
static ReturnValue_t deSerialize(T *object, const uint8_t **buffer,
size_t *size, SerializeIF::Endianness streamEndianness) {
InternalSerializeAdapter<T, IsDerivedFrom<T, SerializeIF>::Is> adapter;
return adapter.deSerialize(object, buffer, size, streamEndianness);
}
private:
template<typename T, int>
class InternalSerializeAdapter {
public:
static ReturnValue_t serialize(const T *object, uint8_t **buffer,
size_t *size, size_t max_size, SerializeIF::Endianness streamEndianness) {
size_t ignoredSize = 0;
if (size == NULL) {
size = &ignoredSize;
}
//TODO check integer overflow of *size
if (sizeof(T) + *size <= max_size) {
T tmp;
switch (streamEndianness) {
case SerializeIF::Endianness::BIG:
tmp = EndianConverter::convertBigEndian<T>(*object);
break;
case SerializeIF::Endianness::LITTLE:
tmp = EndianConverter::convertLittleEndian<T>(*object);
break;
default:
case SerializeIF::Endianness::MACHINE:
tmp = *object;
break;
}
memcpy(*buffer, &tmp, sizeof(T));
*size += sizeof(T);
(*buffer) += sizeof(T);
return HasReturnvaluesIF::RETURN_OK;
} else {
return SerializeIF::BUFFER_TOO_SHORT;
}
}
ReturnValue_t deSerialize(T *object, const uint8_t **buffer,
size_t *size, SerializeIF::Endianness streamEndianness) {
T tmp;
if (*size >= sizeof(T)) {
*size -= sizeof(T);
memcpy(&tmp, *buffer, sizeof(T));
switch (streamEndianness) {
case SerializeIF::Endianness::BIG:
*object = EndianConverter::convertBigEndian<T>(tmp);
break;
case SerializeIF::Endianness::LITTLE:
*object = EndianConverter::convertLittleEndian<T>(tmp);
break;
default:
case SerializeIF::Endianness::MACHINE:
*object = tmp;
break;
}
*buffer += sizeof(T);
return HasReturnvaluesIF::RETURN_OK;
} else {
return SerializeIF::STREAM_TOO_SHORT;
}
}
uint32_t getSerializedSize(const T *object) {
return sizeof(T);
}
};
template<typename T>
class InternalSerializeAdapter<T, 1> {
public:
ReturnValue_t serialize(const T *object, uint8_t **buffer,
size_t *size, size_t max_size,
SerializeIF::Endianness streamEndianness) const {
size_t ignoredSize = 0;
if (size == NULL) {
size = &ignoredSize;
}
return object->serialize(buffer, size, max_size, streamEndianness);
}
uint32_t getSerializedSize(const T *object) const {
return object->getSerializedSize();
}
ReturnValue_t deSerialize(T *object, const uint8_t **buffer,
size_t *size, SerializeIF::Endianness streamEndianness) {
return object->deSerialize(buffer, size, streamEndianness);
}
};
};
#endif /* SERIALIZEADAPTER_H_ */