use new custom type

use a new custom type CPUSet to make the code behave more
like the kubernetes original package.

Signed-off-by: Francesco Romani <fromani@redhat.com>

cpuset_empty.go

@@ -16,7 +16,29 @@
 
 package cpuset
 
-// Empty returns a empty cpuset, a slice of ints
-func Empty() []int {
-	return []int{}
+import "sort"
+
+type CPUSet map[int]struct{}
+
+// Empty returns a empty cpuset
+func Empty() CPUSet {
+	return make(CPUSet)
+}
+
+func (cs CPUSet) Len() int {
+	return len(cs)
+}
+
+func (cs CPUSet) UnsortedList() []int {
+	r := make([]int, 0, len(cs))
+	for k := range cs {
+		r = append(r, k)
+	}
+	return r
+}
+
+func (cs CPUSet) List() []int {
+	r := cs.UnsortedList()
+	sort.Ints(r)
+	return r
 }

cpuset_parse.go

@@ -17,13 +17,12 @@
 package cpuset
 
 import (
-	"sort"
 	"strconv"
 	"strings"
 )
 
 // Parse takes a string representing a cpuset definition, and returns as sorted slice of ints
-func Parse(s string) ([]int, error) {
+func Parse(s string) (CPUSet, error) {
 	cpus := Empty()
 	if len(s) == 0 {
 		return cpus, nil
@@ -37,7 +36,7 @@ func Parse(s string) ([]int, error) {
 			if err != nil {
 				return cpus, err
 			}
-			cpus = append(cpus, cpuid)
+			cpus[cpuid] = struct{}{}
 			continue
 		}
 
@@ -52,10 +51,9 @@ func Parse(s string) ([]int, error) {
 			return cpus, err
 		}
 		for cpuid := cpuBegin; cpuid <= cpuEnd; cpuid++ {
-			cpus = append(cpus, cpuid)
+			cpus[cpuid] = struct{}{}
 		}
 	}
 
-	sort.Ints(cpus)
 	return cpus, nil
 }

cpuset_test.go

@@ -36,8 +36,7 @@ func TestParseEmpty(t *testing.T) {
 func TestParseRange(t *testing.T) {
 	testCases := []tcase{
 		{"0,1,2,3", []int{0, 1, 2, 3}},
-		// we don't elide dupes
-		{"0,1,1,3", []int{0, 1, 1, 3}},
+		{"0,1,3", []int{0, 1, 3}},
 	}
 	for _, testCase := range testCases {
 		testCase.CheckParseSlices(t)
@@ -90,19 +89,19 @@ func TestParseRangeIntervalMalformed(t *testing.T) {
 	}
 }
 
-func mustParse(t *testing.T, s string) []int {
+func mustParse(t *testing.T, s string) CPUSet {
 	cpus, err := Parse(s)
 	if err != nil {
 		t.Errorf("unexpected error: %v", err)
 	}
 	return cpus
 }
 
-func checkEmpty(t *testing.T, cpus []int) {
+func checkEmpty(t *testing.T, cpus CPUSet) {
 	if cpus == nil {
 		t.Errorf("empty must not be nil")
 	}
-	if len(cpus) != 0 {
+	if cpus.Len() != 0 {
 		t.Errorf("empty must have zero length")
 	}
 }
@@ -113,22 +112,22 @@ type tcase struct {
 }
 
 func (tc tcase) CheckParseSlices(t *testing.T) {
-	cpus := mustParse(t, tc.s)
+	cpus := mustParse(t, tc.s).List()
 	if !reflect.DeepEqual(cpus, tc.v) {
 		t.Errorf("slices differ: expected=%v cpus=%v", tc.v, cpus)
 	}
 }
 
 func (tc tcase) CheckUnparseSlices(t *testing.T) {
-	cpus := Unparse(tc.v)
+	cpus := unparseInts(tc.v...)
 	if tc.s != cpus {
 		t.Errorf("strings differ: expected=%q cpus=%q", tc.s, cpus)
 	}
 }
 
 func (tc tcase) CheckParseUnparseSlices(t *testing.T) {
 	cpus := mustParse(t, tc.s)
-	cpuString := Unparse(cpus)
+	cpuString := unparseInts(cpus.List()...)
 	if cpuString != tc.s {
 		t.Errorf("parse/unparse mismatch: expected=%s cpuString=%s cpus=%q", tc.s, cpuString, cpus)
 	}

cpuset_unparse.go

@@ -18,13 +18,14 @@ package cpuset
 
 import (
 	"fmt"
-	"sort"
 	"strings"
 )
 
-// Unparse takes a cpuset as (unsorted) slice of ints and returns a representing cpuset definition
-func Unparse(v []int) string {
-	cpus := sorted(v)
+func Unparse(cs CPUSet) string {
+	return unparseInts(cs.List()...)
+}
+
+func unparseInts(cpus ...int) string {
 	num := len(cpus)
 
 	if num == 0 {
@@ -34,13 +35,6 @@ func Unparse(v []int) string {
 		return fmt.Sprintf("%d", cpus[0])
 	}
 
-	makeAtom := func(cpus []int, begin, end int) string {
-		if begin < (end - 1) { // range
-			return fmt.Sprintf("%d-%d", cpus[begin], cpus[end-1])
-		}
-		return fmt.Sprintf("%d", cpus[begin])
-	}
-
 	var atoms []string
 	begin := 0 // of the potential range
 	end := 1   // of the potential range
@@ -59,9 +53,9 @@ func Unparse(v []int) string {
 	return strings.Join(atoms, ",")
 }
 
-func sorted(v []int) []int {
-	r := make([]int, len(v))
-	copy(r, v)
-	sort.Ints(r)
-	return r
+func makeAtom(cpus []int, begin, end int) string {
+	if begin < (end - 1) { // range
+		return fmt.Sprintf("%d-%d", cpus[begin], cpus[end-1])
+	}
+	return fmt.Sprintf("%d", cpus[begin])
 }

go.mod

@@ -1,3 +1,3 @@
-module github.com/fromanirh/cpuset
+module github.com/ffromani/cpuset
 
-go 1.16
+go 1.18