Struct GraphMask

bool containsAllGraphs

True if the mask contains all graphs, i.e.

if it is equal to GraphMask.everything

bool isPureBitmask

const uint Everything = ~0U

const uint InvertedBit = 1U << 30

const uint LargeGraphIndicesBit = 1U << 31

const uint RemainingGraphIndicesBit = 1U << 30

const uint SmallestLargeGraphIndex = 30

GraphMask everything

A mask containing every graph.

int value

Internal representation of the mask.

Depending on LargeGraphIndicesBit (bit 31) the mask is in one of two modes:

• If LargeGraphIndicesBit is set, then the lower 3x8 bits are used to store indices of 3 graphs (0-254, 255 represents no graph). The InvertedBit (bit 30) is used to indicate if the mask is inverted.

• If LargeGraphIndicesBit is not set, then the lower 30 bits are a normal bitmask for the first 30 graphs, and bit 30 (RemainingGraphIndicesBit) represents all graph indices larger or equal to 30.

Combining two masks is not trivial and can actually throw an exception if you try to combine too many large graph indices. Fortunately, hitting this limit is very rare, and will never happen in normal use.

There are technically two representations that contain all graphs. All bits set, and all bits except the LargeGraphIndicesBit. However, we prevent the latter from being created, to avoid confusion.