fun

const (
	// KeyPerf is a:
	// 3 byte prefix for per-epoch performance keying, followed by:
	// 8 byte big-endian epoch value. (big endian to make db byte-prefix iteration and range-slices follow epoch order)
	//
	// The epoch key represents the boundary when the data became available.
	// I.e. epoch == 2 means that 0 == prev and 1 == current were processed.
	//
	// Values under this key are snappy block-compressed.
	//
	// The value is a []ValidatorPerformance
	KeyPerf string = "prf"
)

const (
	// KeyTile is a:
	// 3 byte prefix for tile keying, followed by:
	// 1 byte tile type
	// 1 byte zoom.
	// 4 byte big endian X
	// 4 byte big endian Y
	//
	// Note: the X is first, so the DB range iterate can range over epochs at zoom 0.
	//
	// Values under this key are snappy block-compressed.
	//
	// The uncompressed value is 4 squares of tileSize x tileSize, one for R, one for G, B, and A
	// The squares encode column by column.
	//
	// We can encode tiles in with R, G, B, A grouped together separately.
	// And implement the image.Image interface to map back to an image.
	// This way we compress better, and don't store as much alpha-channel data.
	KeyTile string = "til"
)