Minor update and new comments

buntdb.go

@@ -1263,12 +1263,15 @@ type dbItem struct {
 	keyless  bool        // keyless item for scanning
 }
 
+// estIntSize returns the string representions size.
+// Has the same result as len(strconv.Itoa(x)).
 func estIntSize(x int) int {
-	if x == 0 {
-		return 1
+	n := 1
+	if x < 0 {
+		n++
+		x *= -1
 	}
-	var n int
-	for x > 0 {
+	for x >= 10 {
 		n++
 		x /= 10
 	}
@@ -1283,7 +1286,10 @@ func estBulkStringSize(s string) int {
 	return 1 + estIntSize(len(s)) + 2 + len(s) + 2
 }
 
-func (dbi *dbItem) estAOFSetSize() (n int) {
+// estAOFSetSize returns an estimated number of bytes that this item will use
+// when stored in the aof file.
+func (dbi *dbItem) estAOFSetSize() int {
+	var n int
 	if dbi.opts != nil && dbi.opts.ex {
 		n += estArraySize(5)
 		n += estBulkStringSize("set")

buntdb_test.go

@@ -13,6 +13,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/tidwall/assert"
 	"github.com/tidwall/lotsa"
 )
 
@@ -2886,3 +2887,25 @@ func TestReloadNotInvalid(t *testing.T) {
 		ii++
 	}
 }
+
+func TestEstSize(t *testing.T) {
+	t.Run("estIntSize", func(t *testing.T) {
+		assert.Assert(estIntSize(0) == 1)
+		assert.Assert(estIntSize(1) == 1)
+		assert.Assert(estIntSize(9) == 1)
+		assert.Assert(estIntSize(10) == 2)
+		assert.Assert(estIntSize(11) == 2)
+		assert.Assert(estIntSize(19) == 2)
+		assert.Assert(estIntSize(20) == 2)
+		assert.Assert(estIntSize(113) == 3)
+		assert.Assert(estIntSize(3822) == 4)
+		assert.Assert(estIntSize(-1) == 2)
+		assert.Assert(estIntSize(-12) == 3)
+		assert.Assert(estIntSize(-124) == 4)
+	})
+	// t.Run("estI
+	// // dbi := dbItem{
+	// // 	key: "hello",
+	// // 	value: "
+	// // }
+}

go.mod

@@ -3,6 +3,7 @@ module github.com/tidwall/buntdb
 go 1.16
 
 require (
+	github.com/tidwall/assert v0.1.0
 	github.com/tidwall/btree v0.6.0
 	github.com/tidwall/gjson v1.8.0
 	github.com/tidwall/grect v0.1.2

go.sum

@@ -1,3 +1,5 @@
+github.com/tidwall/assert v0.1.0 h1:aWcKyRBUAdLoVebxo95N7+YZVTFF/ASTr7BN4sLP6XI=
+github.com/tidwall/assert v0.1.0/go.mod h1:QLYtGyeqse53vuELQheYl9dngGCJQ+mTtlxcktb+Kj8=
 github.com/tidwall/btree v0.6.0 h1:JLYAFGV+1gjyFi3iQbO/fupBin+Ooh7dxqVV0twJ1Bo=
 github.com/tidwall/btree v0.6.0/go.mod h1:TzIRzen6yHbibdSfK6t8QimqbUnoxUSrZfeW7Uob0q4=
 github.com/tidwall/gjson v1.8.0 h1:Qt+orfosKn0rbNTZqHYDqBrmm3UDA4KRkv70fDzG+PQ=