// Copyright 2011 The Go Authors. All rights reserved. // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. package norm type valueRange struct { value uint16 // header: value:stride lo, hi byte // header: lo:n } type sparseBlocks struct { values []valueRange offset []uint16 } var nfcSparse = sparseBlocks{ values: nfcSparseValues[:], offset: nfcSparseOffset[:], } var nfkcSparse = sparseBlocks{ values: nfkcSparseValues[:], offset: nfkcSparseOffset[:], } var ( nfcData = newNfcTrie(0) nfkcData = newNfkcTrie(0) ) // lookup determines the type of block n and looks up the value for b. // For n < t.cutoff, the block is a simple lookup table. Otherwise, the block // is a list of ranges with an accompanying value. Given a matching range r, // the value for b is by r.value + (b - r.lo) * stride. func (t *sparseBlocks) lookup(n uint32, b byte) uint16 { offset := t.offset[n] header := t.values[offset] lo := offset + 1 hi := lo + uint16(header.lo) for lo < hi { m := lo + (hi-lo)/2 r := t.values[m] if r.lo <= b && b <= r.hi { return r.value + uint16(b-r.lo)*header.value } if b < r.lo { hi = m } else { lo = m + 1 } } return 0 }