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package miniredis
// The most KISS way to implement a sorted set. Luckily we don't care about
// performance that much.
import (
"sort"
)
type direction int
const (
asc direction = iota
desc
)
type sortedSet map[string]float64
type ssElem struct {
score float64
member string
}
type ssElems []ssElem
type byScore ssElems
func (sse byScore) Len() int { return len(sse) }
func (sse byScore) Swap(i, j int) { sse[i], sse[j] = sse[j], sse[i] }
func (sse byScore) Less(i, j int) bool {
if sse[i].score != sse[j].score {
return sse[i].score < sse[j].score
}
return sse[i].member < sse[j].member
}
func newSortedSet() sortedSet {
return sortedSet{}
}
func (ss *sortedSet) card() int {
return len(*ss)
}
func (ss *sortedSet) set(score float64, member string) {
(*ss)[member] = score
}
func (ss *sortedSet) get(member string) (float64, bool) {
v, ok := (*ss)[member]
return v, ok
}
// elems gives the list of ssElem, ready to sort.
func (ss *sortedSet) elems() ssElems {
elems := make(ssElems, 0, len(*ss))
for e, s := range *ss {
elems = append(elems, ssElem{s, e})
}
return elems
}
func (ss *sortedSet) byScore(d direction) ssElems {
elems := ss.elems()
sort.Sort(byScore(elems))
if d == desc {
reverseElems(elems)
}
return ssElems(elems)
}
// rankByScore gives the (0-based) index of member, or returns false.
func (ss *sortedSet) rankByScore(member string, d direction) (int, bool) {
if _, ok := (*ss)[member]; !ok {
return 0, false
}
for i, e := range ss.byScore(d) {
if e.member == member {
return i, true
}
}
// Can't happen
return 0, false
}
func reverseSlice(o []string) {
for i := range make([]struct{}, len(o)/2) {
other := len(o) - 1 - i
o[i], o[other] = o[other], o[i]
}
}
func reverseElems(o ssElems) {
for i := range make([]struct{}, len(o)/2) {
other := len(o) - 1 - i
o[i], o[other] = o[other], o[i]
}
}
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