const (
	lengthMask = 0x07
	lengthBits = 3
	noChange   = 0
)

// References to generated trie.

var trie = newCaseTrie(0)

var sparse = sparseBlocks{
	values:  sparseValues[:],
	offsets: sparseOffsets[:],
}

// Sparse block lookup code.

// valueRange is an entry in a sparse block.
type valueRange struct {
	value  uint16
	lo, hi byte
}

type sparseBlocks struct {