encoding/asn1: speed up marshal by reducing allocations
Replace strings.Split by strings.IndexByte and explicit
slicing to avoid the allocation of the return slice
of strings.Split.
name old time/op new time/op delta
Marshal 43.3µs ± 1% 36.7µs ± 1% -15.23% (p=0.000 n=9+9)
name old alloc/op new alloc/op delta
Marshal 10.7kB ± 0% 9.2kB ± 0% -13.96% (p=0.000 n=10+10)
name old allocs/op new allocs/op delta
Marshal 444 ± 0% 366 ± 0% -17.57% (p=0.000 n=10+10)
Change-Id: I9e727defa23f7e5fc684f246de0136fe28cf8d25
Reviewed-on: https://go-review.googlesource.com/c/go/+/231738
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
diff --git a/src/encoding/asn1/common.go b/src/encoding/asn1/common.go
index e2aa8bd..1c712e1 100644
--- a/src/encoding/asn1/common.go
+++ b/src/encoding/asn1/common.go
@@ -92,7 +92,16 @@
// parseFieldParameters will parse it into a fieldParameters structure,
// ignoring unknown parts of the string.
func parseFieldParameters(str string) (ret fieldParameters) {
- for _, part := range strings.Split(str, ",") {
+ var part string
+ for len(str) > 0 {
+ // This loop uses IndexByte and explicit slicing
+ // instead of strings.Split(str, ",") to reduce allocations.
+ i := strings.IndexByte(str, ',')
+ if i < 0 {
+ part, str = str, ""
+ } else {
+ part, str = str[:i], str[i+1:]
+ }
switch {
case part == "optional":
ret.optional = true
