pack and unpack list of periods

aggregator.go

@@ -7,7 +7,7 @@ import (
 	"time"
 )
 
-type Period int64
+type Period uint64
 
 type TimeAggregator struct {
 	Values  map[Period]*Aggregator
@@ -22,7 +22,7 @@ func NewTimeAggregator(p ...PeriodDefinition) *TimeAggregator {
 }
 
 func (a *TimeAggregator) Add(date time.Time, value int64) {
-	p := a.periods.calc(date)
+	p := a.periods.pack(date)
 
 	if _, ok := a.Values[p]; !ok {
 		a.Values[p] = a.buildAggregator()
@@ -32,7 +32,7 @@ func (a *TimeAggregator) Add(date time.Time, value int64) {
 }
 
 func (a *TimeAggregator) Get(date time.Time) int64 {
-	p := a.periods.calc(date)
+	p := a.periods.pack(date)
 
 	if _, ok := a.Values[p]; !ok {
 		return -1

periods.go

@@ -6,7 +6,7 @@ import (
 
 type PeriodDefinition struct {
 	size int8
-	pad  int64
+	pad  uint64
 	name string
 	cast func(date time.Time) Period
 }
@@ -49,25 +49,27 @@ var Weekday = PeriodDefinition{
 
 type periodDefinitions []PeriodDefinition
 
-func (p periodDefinitions) calc(date time.Time) Period {
-	var t Period
+func (p periodDefinitions) pack(date time.Time) Period {
+	t := Period(1)
 	for _, p := range p[:len(p)-1] {
-		t += (p.cast(date) * Period(p.pad))
+		t *= Period(p.pad)
+		t += p.cast(date)
 	}
 
 	return t
 }
 
-/*
-
-func (p periodDefinitions) extract(date time.Time) map[string]int64 {
-    result := make(map[string]int64, 0)
-
-    for _, p := range p[:len(p)-1] {
-        result[p.name] =
-    }
+func (p periodDefinitions) unpack(total Period) map[string]uint64 {
+	result := make(map[string]uint64, 0)
+	t := uint64(total)
+	for i := len(p) - 2; i >= 0; i-- {
+		result[p[i].name] = t % p[i].pad
+		t = t / p[i].pad
+	}
 
-    fmt.Println("period", t)
+	if t != 1 {
+		panic("Malformed period")
+	}
 
-    return t
-}*/
+	return result
+}

periods_test.go

@@ -0,0 +1,16 @@
+package ta
+
+import (
+	. "gopkg.in/check.v1"
+)
+
+func (s *UtilsSuite) TestperiodDefinitions_pack(c *C) {
+	ps := periodDefinitions{Year, Month, Weekday}
+	c.Assert(ps.pack(date2015November), Equals, Period(1201511))
+}
+
+func (s *UtilsSuite) TestperiodDefinitions_unpack(c *C) {
+	ps := periodDefinitions{Year, Month, Weekday}
+	p := ps.unpack(Period(1201511))
+	c.Assert(p, DeepEquals, map[string]uint64{"year": 2015, "month": 11})
+}