PayloadHelpers Namespace Reference

Collection of helper functions for raw pointer operations on the bytestream payload. More...

Typedefs
using	TDA = TriggerEDMDeserialiserAlg

Functions
CLID	collectionCLID (TDA::PayloadIterator start)
	CLID of the collection stored in the next fragment. More...
size_t	nameLength (TDA::PayloadIterator start)
	Length of the serialised name payload. More...
size_t	dataSize (TDA::PayloadIterator start)
	Size in bytes of the buffer that is needed to decode next fragment data content. More...
TDA::PayloadIterator	toNextFragment (TDA::PayloadIterator start)
	Returns starting point of the next fragment, can be == end() More...
std::vector< std::string >	collectionDescription (TDA::PayloadIterator start)
	String description of the collection stored in the next fragment, returns persistent type name and the SG key. More...
void	toBuffer (TDA::PayloadIterator start, char *buffer)
	Copies fragment to the buffer, no size checking, use dataSize to do so. More...

Detailed Description

Collection of helper functions for raw pointer operations on the bytestream payload.

Most functions can be constexpr if the compiler implements ConstexprIterator (P0858R0) Tested it works in clang9 (and 10 and 11?) regardless of –std flag and in gcc10+ only with –std=c++20 But clang12 requires –std=c++20. TODO: Remove the C++ version checks when the release is built with –std=c++20 or newer

Typedef Documentation

TDA

using PayloadHelpers::TDA = typedef TriggerEDMDeserialiserAlg

Definition at line 166 of file TriggerEDMDeserialiserAlg.cxx.

Function Documentation

collectionCLID()

CLID PayloadHelpers::collectionCLID

(

TDA::PayloadIterator

start

)

CLID of the collection stored in the next fragment.

Definition at line 172 of file TriggerEDMDeserialiserAlg.cxx.

                                                {
    return *( start + TDA::CLIDOffset );
  }

collectionDescription()

std::vector<std::string> PayloadHelpers::collectionDescription

(

TDA::PayloadIterator

start

)

String description of the collection stored in the next fragment, returns persistent type name and the SG key.

Definition at line 205 of file TriggerEDMDeserialiserAlg.cxx.

                                                                       {
    StringSerializer ss;
    std::vector<std::string> labels;
    ss.deserialize( start + TDA::NameOffset, start + TDA::NameOffset + nameLength(start), labels );
    return labels;
  }

dataSize()

size_t PayloadHelpers::dataSize

(

TDA::PayloadIterator

start

)

Size in bytes of the buffer that is needed to decode next fragment data content.

Definition at line 188 of file TriggerEDMDeserialiserAlg.cxx.

                                            {
    return *( start + TDA::NameOffset + nameLength(start) );
  }

nameLength()

size_t PayloadHelpers::nameLength

(

TDA::PayloadIterator

start

)

Length of the serialised name payload.

Definition at line 180 of file TriggerEDMDeserialiserAlg.cxx.

                                              {
    return *( start + TDA::NameLengthOffset );
  }

toBuffer()

void PayloadHelpers::toBuffer	(	TDA::PayloadIterator	start,
		char *	buffer
	)

Copies fragment to the buffer, no size checking, use dataSize to do so.

Definition at line 213 of file TriggerEDMDeserialiserAlg.cxx.

                                                        {
    // move to the beginning of the buffer memory
    TDA::PayloadIterator dataStart =  start + TDA::NameOffset + nameLength(start) + 1 /*skip size*/;
    // we rely on continuous memory layout of std::vector ...
    std::memcpy( buffer, &(*dataStart), dataSize(start) );
  }

toNextFragment()

TDA::PayloadIterator PayloadHelpers::toNextFragment

(

TDA::PayloadIterator

start

)

Returns starting point of the next fragment, can be == end()

Intended to be used like this: start = advance(start); if ( start != data.end() )... decode else ... done

Definition at line 200 of file TriggerEDMDeserialiserAlg.cxx.

                                                              {
    return start + (*start); // point ahead by the number of words pointed to by start iterator
  }