trie.go (1868B)
1 // Code generated by running "go generate" in golang.org/x/text. DO NOT EDIT. 2 3 // Copyright 2016 The Go Authors. All rights reserved. 4 // Use of this source code is governed by a BSD-style 5 // license that can be found in the LICENSE file. 6 7 package idna 8 9 // appendMapping appends the mapping for the respective rune. isMapped must be 10 // true. A mapping is a categorization of a rune as defined in UTS #46. 11 func (c info) appendMapping(b []byte, s string) []byte { 12 index := int(c >> indexShift) 13 if c&xorBit == 0 { 14 s := mappings[index:] 15 return append(b, s[1:s[0]+1]...) 16 } 17 b = append(b, s...) 18 if c&inlineXOR == inlineXOR { 19 // TODO: support and handle two-byte inline masks 20 b[len(b)-1] ^= byte(index) 21 } else { 22 for p := len(b) - int(xorData[index]); p < len(b); p++ { 23 index++ 24 b[p] ^= xorData[index] 25 } 26 } 27 return b 28 } 29 30 // Sparse block handling code. 31 32 type valueRange struct { 33 value uint16 // header: value:stride 34 lo, hi byte // header: lo:n 35 } 36 37 type sparseBlocks struct { 38 values []valueRange 39 offset []uint16 40 } 41 42 var idnaSparse = sparseBlocks{ 43 values: idnaSparseValues[:], 44 offset: idnaSparseOffset[:], 45 } 46 47 // Don't use newIdnaTrie to avoid unconditional linking in of the table. 48 var trie = &idnaTrie{} 49 50 // lookup determines the type of block n and looks up the value for b. 51 // For n < t.cutoff, the block is a simple lookup table. Otherwise, the block 52 // is a list of ranges with an accompanying value. Given a matching range r, 53 // the value for b is by r.value + (b - r.lo) * stride. 54 func (t *sparseBlocks) lookup(n uint32, b byte) uint16 { 55 offset := t.offset[n] 56 header := t.values[offset] 57 lo := offset + 1 58 hi := lo + uint16(header.lo) 59 for lo < hi { 60 m := lo + (hi-lo)/2 61 r := t.values[m] 62 if r.lo <= b && b <= r.hi { 63 return r.value + uint16(b-r.lo)*header.value 64 } 65 if b < r.lo { 66 hi = m 67 } else { 68 lo = m + 1 69 } 70 } 71 return 0 72 }