slices: reduce code nesting depth for Compact and CompactFunc

To make it easier to read.

Change-Id: I2fa1eb78d879b9d86b4dc839be7ede37c7c864f4
Reviewed-on: https://go-review.googlesource.com/c/go/+/581976
Auto-Submit: Ian Lance Taylor <iant@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Joedian Reid <joedian@google.com>
This commit is contained in:
Jes Cok 2024-04-26 21:49:41 +08:00 committed by Gopher Robot
parent 9e0685f9c2
commit cf164403d1

View File

@ -355,20 +355,21 @@ func Clone[S ~[]E, E any](s S) S {
// which may have a smaller length.
// Compact zeroes the elements between the new length and the original length.
func Compact[S ~[]E, E comparable](s S) S {
if len(s) > 1 {
for k := 1; k < len(s); k++ {
if s[k] == s[k-1] {
s2 := s[k:]
for k2 := 1; k2 < len(s2); k2++ {
if s2[k2] != s2[k2-1] {
s[k] = s2[k2]
k++
}
if len(s) < 2 {
return s
}
for k := 1; k < len(s); k++ {
if s[k] == s[k-1] {
s2 := s[k:]
for k2 := 1; k2 < len(s2); k2++ {
if s2[k2] != s2[k2-1] {
s[k] = s2[k2]
k++
}
clear(s[k:]) // zero/nil out the obsolete elements, for GC
return s[:k]
}
clear(s[k:]) // zero/nil out the obsolete elements, for GC
return s[:k]
}
}
return s
@ -378,20 +379,21 @@ func Compact[S ~[]E, E comparable](s S) S {
// For runs of elements that compare equal, CompactFunc keeps the first one.
// CompactFunc zeroes the elements between the new length and the original length.
func CompactFunc[S ~[]E, E any](s S, eq func(E, E) bool) S {
if len(s) > 1 {
for k := 1; k < len(s); k++ {
if eq(s[k], s[k-1]) {
s2 := s[k:]
for k2 := 1; k2 < len(s2); k2++ {
if !eq(s2[k2], s2[k2-1]) {
s[k] = s2[k2]
k++
}
if len(s) < 2 {
return s
}
for k := 1; k < len(s); k++ {
if eq(s[k], s[k-1]) {
s2 := s[k:]
for k2 := 1; k2 < len(s2); k2++ {
if !eq(s2[k2], s2[k2-1]) {
s[k] = s2[k2]
k++
}
clear(s[k:]) // zero/nil out the obsolete elements, for GC
return s[:k]
}
clear(s[k:]) // zero/nil out the obsolete elements, for GC
return s[:k]
}
}
return s