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-rw-r--r--vendor/golang.org/x/text/internal/tag/tag.go100
1 files changed, 100 insertions, 0 deletions
diff --git a/vendor/golang.org/x/text/internal/tag/tag.go b/vendor/golang.org/x/text/internal/tag/tag.go
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+// Copyright 2015 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 tag contains functionality handling tags and related data.
+package tag // import "golang.org/x/text/internal/tag"
+
+import "sort"
+
+// An Index converts tags to a compact numeric value.
+//
+// All elements are of size 4. Tags may be up to 4 bytes long. Excess bytes can
+// be used to store additional information about the tag.
+type Index string
+
+// Elem returns the element data at the given index.
+func (s Index) Elem(x int) string {
+ return string(s[x*4 : x*4+4])
+}
+
+// Index reports the index of the given key or -1 if it could not be found.
+// Only the first len(key) bytes from the start of the 4-byte entries will be
+// considered for the search and the first match in Index will be returned.
+func (s Index) Index(key []byte) int {
+ n := len(key)
+ // search the index of the first entry with an equal or higher value than
+ // key in s.
+ index := sort.Search(len(s)/4, func(i int) bool {
+ return cmp(s[i*4:i*4+n], key) != -1
+ })
+ i := index * 4
+ if cmp(s[i:i+len(key)], key) != 0 {
+ return -1
+ }
+ return index
+}
+
+// Next finds the next occurrence of key after index x, which must have been
+// obtained from a call to Index using the same key. It returns x+1 or -1.
+func (s Index) Next(key []byte, x int) int {
+ if x++; x*4 < len(s) && cmp(s[x*4:x*4+len(key)], key) == 0 {
+ return x
+ }
+ return -1
+}
+
+// cmp returns an integer comparing a and b lexicographically.
+func cmp(a Index, b []byte) int {
+ n := len(a)
+ if len(b) < n {
+ n = len(b)
+ }
+ for i, c := range b[:n] {
+ switch {
+ case a[i] > c:
+ return 1
+ case a[i] < c:
+ return -1
+ }
+ }
+ switch {
+ case len(a) < len(b):
+ return -1
+ case len(a) > len(b):
+ return 1
+ }
+ return 0
+}
+
+// Compare returns an integer comparing a and b lexicographically.
+func Compare(a string, b []byte) int {
+ return cmp(Index(a), b)
+}
+
+// FixCase reformats b to the same pattern of cases as form.
+// If returns false if string b is malformed.
+func FixCase(form string, b []byte) bool {
+ if len(form) != len(b) {
+ return false
+ }
+ for i, c := range b {
+ if form[i] <= 'Z' {
+ if c >= 'a' {
+ c -= 'z' - 'Z'
+ }
+ if c < 'A' || 'Z' < c {
+ return false
+ }
+ } else {
+ if c <= 'Z' {
+ c += 'z' - 'Z'
+ }
+ if c < 'a' || 'z' < c {
+ return false
+ }
+ }
+ b[i] = c
+ }
+ return true
+}