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Refactoring collections/orderedintset and benchmarks for it
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Docker-DCO-1.1-Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com> (github: LK4D4)
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LK4D4 committed May 14, 2014
1 parent 4de6810 commit 5128feb
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Showing 2 changed files with 111 additions and 41 deletions.
81 changes: 40 additions & 41 deletions pkg/collections/orderedintset.go
@@ -1,12 +1,13 @@
package collections

import (
"sort"
"sync"
)

// OrderedIntSet is a thread-safe sorted set and a stack.
type OrderedIntSet struct {
sync.RWMutex
sync.Mutex
set []int
}

Expand All @@ -15,29 +16,22 @@ func NewOrderedIntSet() *OrderedIntSet {
return &OrderedIntSet{}
}

// Push takes a string and adds it to the set. If the elem aready exists, it has no effect.
// Push takes an int and adds it to the set. If the elem aready exists, it has no effect.
func (s *OrderedIntSet) Push(elem int) {
s.RLock()
for _, e := range s.set {
if e == elem {
s.RUnlock()
return
}
}
s.RUnlock()

s.Lock()
if len(s.set) == 0 {
s.set = append(s.set, elem)
s.Unlock()
return
}

// Make sure the list is always sorted
for i, e := range s.set {
if elem < e {
s.set = append(s.set[:i], append([]int{elem}, s.set[i:]...)...)
s.Unlock()
return
}
i := sort.SearchInts(s.set, elem)
if i < len(s.set) && s.set[i] == elem {
s.Unlock()
return
}
// If we reach here, then elem is the biggest elem of the list.
s.set = append(s.set, elem)
s.set = append(s.set[:i], append([]int{elem}, s.set[i:]...)...)
s.Unlock()
}

Expand All @@ -46,28 +40,26 @@ func (s *OrderedIntSet) Pop() int {
return s.PopFront()
}

// Pop returns the first elemen from the list and removes it.
// Pop returns the first element from the list and removes it.
// If the list is empty, it returns 0
func (s *OrderedIntSet) PopFront() int {
s.RLock()

for i, e := range s.set {
ret := e
s.RUnlock()
s.Lock()
s.set = append(s.set[:i], s.set[i+1:]...)
s.Lock()
if len(s.set) == 0 {
s.Unlock()
return ret
return 0
}
s.RUnlock()

return 0
ret := s.set[0]
s.set = s.set[1:]
s.Unlock()
return ret
}

// PullBack retrieve the last element of the list.
// The element is not removed.
// If the list is empty, an empty element is returned.
func (s *OrderedIntSet) PullBack() int {
s.Lock()
defer s.Unlock()
if len(s.set) == 0 {
return 0
}
Expand All @@ -76,21 +68,28 @@ func (s *OrderedIntSet) PullBack() int {

// Exists checks if the given element present in the list.
func (s *OrderedIntSet) Exists(elem int) bool {
for _, e := range s.set {
if e == elem {
return true
}
s.Lock()
if len(s.set) == 0 {
s.Unlock()
return false
}
return false
i := sort.SearchInts(s.set, elem)
res := i < len(s.set) && s.set[i] == elem
s.Unlock()
return res
}

// Remove removes an element from the list.
// If the element is not found, it has no effect.
func (s *OrderedIntSet) Remove(elem int) {
for i, e := range s.set {
if e == elem {
s.set = append(s.set[:i], s.set[i+1:]...)
return
}
s.Lock()
if len(s.set) == 0 {
s.Unlock()
return
}
i := sort.SearchInts(s.set, elem)
if i < len(s.set) && s.set[i] == elem {
s.set = append(s.set[:i], s.set[i+1:]...)
}
s.Unlock()
}
71 changes: 71 additions & 0 deletions pkg/collections/orderedintset_test.go
@@ -0,0 +1,71 @@
package collections

import (
"math/rand"
"testing"
)

func BenchmarkPush(b *testing.B) {
var testSet []int
for i := 0; i < 1000; i++ {
testSet = append(testSet, rand.Int())
}
s := NewOrderedIntSet()
b.ResetTimer()
for i := 0; i < b.N; i++ {
for _, elem := range testSet {
s.Push(elem)
}
}
}

func BenchmarkPop(b *testing.B) {
var testSet []int
for i := 0; i < 1000; i++ {
testSet = append(testSet, rand.Int())
}
s := NewOrderedIntSet()
for _, elem := range testSet {
s.Push(elem)
}
b.ResetTimer()
for i := 0; i < b.N; i++ {
for j := 0; j < 1000; j++ {
s.Pop()
}
}
}

func BenchmarkExist(b *testing.B) {
var testSet []int
for i := 0; i < 1000; i++ {
testSet = append(testSet, rand.Intn(2000))
}
s := NewOrderedIntSet()
for _, elem := range testSet {
s.Push(elem)
}
b.ResetTimer()
for i := 0; i < b.N; i++ {
for j := 0; j < 1000; j++ {
s.Exists(j)
}
}
}

func BenchmarkRemove(b *testing.B) {
var testSet []int
for i := 0; i < 1000; i++ {
testSet = append(testSet, rand.Intn(2000))
}
s := NewOrderedIntSet()
for _, elem := range testSet {
s.Push(elem)
}
b.ResetTimer()
for i := 0; i < b.N; i++ {
for j := 0; j < 1000; j++ {
s.Remove(j)
}
}
}

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