Revert "Use a flat slice for pending request counts"

This reverts commit dfc421824c.

pending-requests.go

@@ -1,33 +1,50 @@
 package torrent
 
+import (
+	rbm "github.com/RoaringBitmap/roaring"
+	roaring "github.com/RoaringBitmap/roaring/BitSliceIndexing"
+)
+
 type pendingRequests struct {
-	m []int
+	m *roaring.BSI
 }
 
 func (p *pendingRequests) Dec(r RequestIndex) {
-	prev := p.m[r]
+	_r := uint64(r)
+	prev, _ := p.m.GetValue(_r)
 	if prev <= 0 {
 		panic(prev)
 	}
-	p.m[r]--
+	p.m.SetValue(_r, prev-1)
 }
 
 func (p *pendingRequests) Inc(r RequestIndex) {
-	p.m[r]++
+	_r := uint64(r)
+	prev, _ := p.m.GetValue(_r)
+	p.m.SetValue(_r, prev+1)
 }
 
 func (p *pendingRequests) Init(maxIndex RequestIndex) {
-	p.m = make([]int, maxIndex)
+	p.m = roaring.NewDefaultBSI()
+}
+
+var allBits rbm.Bitmap
+
+func init() {
+	allBits.AddRange(0, rbm.MaxRange)
 }
 
 func (p *pendingRequests) AssertEmpty() {
-	for _, count := range p.m {
-		if count != 0 {
-			panic(count)
+	if p.m == nil {
+		panic(p.m)
 	}
+	sum, _ := p.m.Sum(&allBits)
+	if sum != 0 {
+		panic(sum)
 	}
 }
 
 func (p *pendingRequests) Get(r RequestIndex) int {
-	return p.m[r]
+	count, _ := p.m.GetValue(uint64(r))
+	return int(count)
 }