/usr/share/gocode/src/golang.org/x/text/internal/colltab/contract.go is in golang-golang-x-text-dev 0.0~git20170627.0.6353ef0-1ubuntu2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 | // Copyright 2012 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 colltab
import "unicode/utf8"
// For a description of ContractTrieSet, see text/collate/build/contract.go.
type ContractTrieSet []struct{ L, H, N, I uint8 }
// ctScanner is used to match a trie to an input sequence.
// A contraction may match a non-contiguous sequence of bytes in an input string.
// For example, if there is a contraction for <a, combining_ring>, it should match
// the sequence <a, combining_cedilla, combining_ring>, as combining_cedilla does
// not block combining_ring.
// ctScanner does not automatically skip over non-blocking non-starters, but rather
// retains the state of the last match and leaves it up to the user to continue
// the match at the appropriate points.
type ctScanner struct {
states ContractTrieSet
s []byte
n int
index int
pindex int
done bool
}
type ctScannerString struct {
states ContractTrieSet
s string
n int
index int
pindex int
done bool
}
func (t ContractTrieSet) scanner(index, n int, b []byte) ctScanner {
return ctScanner{s: b, states: t[index:], n: n}
}
func (t ContractTrieSet) scannerString(index, n int, str string) ctScannerString {
return ctScannerString{s: str, states: t[index:], n: n}
}
// result returns the offset i and bytes consumed p so far. If no suffix
// matched, i and p will be 0.
func (s *ctScanner) result() (i, p int) {
return s.index, s.pindex
}
func (s *ctScannerString) result() (i, p int) {
return s.index, s.pindex
}
const (
final = 0
noIndex = 0xFF
)
// scan matches the longest suffix at the current location in the input
// and returns the number of bytes consumed.
func (s *ctScanner) scan(p int) int {
pr := p // the p at the rune start
str := s.s
states, n := s.states, s.n
for i := 0; i < n && p < len(str); {
e := states[i]
c := str[p]
// TODO: a significant number of contractions are of a form that
// cannot match discontiguous UTF-8 in a normalized string. We could let
// a negative value of e.n mean that we can set s.done = true and avoid
// the need for additional matches.
if c >= e.L {
if e.L == c {
p++
if e.I != noIndex {
s.index = int(e.I)
s.pindex = p
}
if e.N != final {
i, states, n = 0, states[int(e.H)+n:], int(e.N)
if p >= len(str) || utf8.RuneStart(str[p]) {
s.states, s.n, pr = states, n, p
}
} else {
s.done = true
return p
}
continue
} else if e.N == final && c <= e.H {
p++
s.done = true
s.index = int(c-e.L) + int(e.I)
s.pindex = p
return p
}
}
i++
}
return pr
}
// scan is a verbatim copy of ctScanner.scan.
func (s *ctScannerString) scan(p int) int {
pr := p // the p at the rune start
str := s.s
states, n := s.states, s.n
for i := 0; i < n && p < len(str); {
e := states[i]
c := str[p]
// TODO: a significant number of contractions are of a form that
// cannot match discontiguous UTF-8 in a normalized string. We could let
// a negative value of e.n mean that we can set s.done = true and avoid
// the need for additional matches.
if c >= e.L {
if e.L == c {
p++
if e.I != noIndex {
s.index = int(e.I)
s.pindex = p
}
if e.N != final {
i, states, n = 0, states[int(e.H)+n:], int(e.N)
if p >= len(str) || utf8.RuneStart(str[p]) {
s.states, s.n, pr = states, n, p
}
} else {
s.done = true
return p
}
continue
} else if e.N == final && c <= e.H {
p++
s.done = true
s.index = int(c-e.L) + int(e.I)
s.pindex = p
return p
}
}
i++
}
return pr
}
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