mirror of
https://github.com/Luzifer/nginx-sso.git
synced 2024-12-30 09:41:19 +00:00
86 lines
2 KiB
Go
86 lines
2 KiB
Go
// Copyright 2016 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 stringset provides a way to represent a collection of strings
|
|
// compactly.
|
|
package stringset
|
|
|
|
import "sort"
|
|
|
|
// A Set holds a collection of strings that can be looked up by an index number.
|
|
type Set struct {
|
|
// These fields are exported to allow for code generation.
|
|
|
|
Data string
|
|
Index []uint16
|
|
}
|
|
|
|
// Elem returns the string with index i. It panics if i is out of range.
|
|
func (s *Set) Elem(i int) string {
|
|
return s.Data[s.Index[i]:s.Index[i+1]]
|
|
}
|
|
|
|
// Len returns the number of strings in the set.
|
|
func (s *Set) Len() int {
|
|
return len(s.Index) - 1
|
|
}
|
|
|
|
// Search returns the index of the given string or -1 if it is not in the set.
|
|
// The Set must have been created with strings in sorted order.
|
|
func Search(s *Set, str string) int {
|
|
// TODO: optimize this if it gets used a lot.
|
|
n := len(s.Index) - 1
|
|
p := sort.Search(n, func(i int) bool {
|
|
return s.Elem(i) >= str
|
|
})
|
|
if p == n || str != s.Elem(p) {
|
|
return -1
|
|
}
|
|
return p
|
|
}
|
|
|
|
// A Builder constructs Sets.
|
|
type Builder struct {
|
|
set Set
|
|
index map[string]int
|
|
}
|
|
|
|
// NewBuilder returns a new and initialized Builder.
|
|
func NewBuilder() *Builder {
|
|
return &Builder{
|
|
set: Set{
|
|
Index: []uint16{0},
|
|
},
|
|
index: map[string]int{},
|
|
}
|
|
}
|
|
|
|
// Set creates the set created so far.
|
|
func (b *Builder) Set() Set {
|
|
return b.set
|
|
}
|
|
|
|
// Index returns the index for the given string, which must have been added
|
|
// before.
|
|
func (b *Builder) Index(s string) int {
|
|
return b.index[s]
|
|
}
|
|
|
|
// Add adds a string to the index. Strings that are added by a single Add will
|
|
// be stored together, unless they match an existing string.
|
|
func (b *Builder) Add(ss ...string) {
|
|
// First check if the string already exists.
|
|
for _, s := range ss {
|
|
if _, ok := b.index[s]; ok {
|
|
continue
|
|
}
|
|
b.index[s] = len(b.set.Index) - 1
|
|
b.set.Data += s
|
|
x := len(b.set.Data)
|
|
if x > 0xFFFF {
|
|
panic("Index too > 0xFFFF")
|
|
}
|
|
b.set.Index = append(b.set.Index, uint16(x))
|
|
}
|
|
}
|