Classes
class	DistinctNucleus

struct	TestFrameTable

Functions
TestFrame &	accessAsTestFrame (void *memoryLocation)

auto	buildDataGenFrom (uint64_t const &anchor)

HashVal	drawSeed (lib::Random &srcGen)

uint64_t	generateDiscriminator (uint seq, uint family)

HashVal	stampHeader ()

Variables
HashVal	dataSeed {drawSeed(lib::entropyGen)}

const size_t	SEQUENCE_SPREAD = 100
	Offset to set the seed values of »families« apart. More...

std::unique_ptr< TestFrameTable >	testFrames

Function Documentation

◆ generateDiscriminator()

uint64_t steam::engine::test::anonymous_namespace{testframe.cpp}::generateDiscriminator	(	uint	seq,
		uint	family
	)

helper for generating unique test frames. This »discriminator« is used as a random seed when filling the test frame data buffers. It is generated to be very likely different on adjacent frames of the same series, as well as to differ to all nearby neighbouring channels.

Note: the dataSeed hash is limited by SEQUENCE_SPREAD to prevent „risky“ families; the extreme case would be dataSeed+family ≡ 0 (all frames would be equal then)

Parameters

seq	the sequence number of the frame within the channel
family	the channel this frame belongs to

Definition at line 94 of file testframe.cpp.

References dataSeed.

◆ stampHeader()

HashVal steam::engine::test::anonymous_namespace{testframe.cpp}::stampHeader ( )

Returns: a stable characteristic memory marker for the metadata record

Definition at line 120 of file testframe.cpp.

◆ buildDataGenFrom()

auto steam::engine::test::anonymous_namespace{testframe.cpp}::buildDataGenFrom ( uint64_t const & anchor )

build a PRNG starting from the referred fixed seed

Definition at line 129 of file testframe.cpp.

Variable Documentation

◆ SEQUENCE_SPREAD

const size_t SEQUENCE_SPREAD = 100

Offset to set the seed values of »families« apart.

The data in the test frames is generated from a distinctive ID-seed, which is controlled by the family and the seq-No within each family. The seeds for consecutive frames are spread apart by the dataSeed, and the SEQUENCE_SPREAD constant acts as minimum spread. While seed values can wrap within the 64bit number range, this generation scheme makes it very unlikely that neighbouring frames end up with the same seed.

Definition at line 71 of file testframe.cpp.

◆ dataSeed

HashVal dataSeed {drawSeed(lib::entropyGen)}

a static seed hash used to anchor the data distinction ID-seeds

Definition at line 82 of file testframe.cpp.

Referenced by generateDiscriminator().

Classes

Functions