// Delete removes the elements s[i:j] from s, returning the modified slice.
// Delete panics if j > len(s) or s[i:j] is not a valid slice of s.
-// Delete is O(len(s)-j), so if many items must be deleted, it is better to
+// Delete is O(len(s)-i), so if many items must be deleted, it is better to
// make a single call deleting them all together than to delete one at a time.
-// Delete might not modify the elements s[len(s)-(j-i):len(s)]. If those
-// elements contain pointers you might consider zeroing those elements so that
-// objects they reference can be garbage collected.
+// Delete zeroes the elements s[len(s)-(j-i):len(s)].
func Delete[S ~[]E, E any](s S, i, j int) S {
_ = s[i:j] // bounds check
- return append(s[:i], s[j:]...)
+ oldlen := len(s)
+ s = append(s[:i], s[j:]...)
+ clear(s[len(s):oldlen]) // zero/nil out the obsolete elements, for GC
+ return s
}
// DeleteFunc removes any elements from s for which del returns true,
// returning the modified slice.
-// When DeleteFunc removes m elements, it might not modify the elements
-// s[len(s)-m:len(s)]. If those elements contain pointers you might consider
-// zeroing those elements so that objects they reference can be garbage
-// collected.
+// DeleteFunc zeroes the elements between the new length and the original length.
func DeleteFunc[S ~[]E, E any](s S, del func(E) bool) S {
i := IndexFunc(s, del)
if i == -1 {
i++
}
}
+ clear(s[i:]) // zero/nil out the obsolete elements, for GC
return s[:i]
}
// Replace replaces the elements s[i:j] by the given v, and returns the
// modified slice.
// Replace panics if j > len(s) or s[i:j] is not a valid slice of s.
+// When len(v) < (j-i), Replace zeroes the elements between the new length and the original length.
func Replace[S ~[]E, E any](s S, i, j int, v ...E) S {
_ = s[i:j] // bounds check
// Easy, as v fits in the deleted portion.
copy(r[i:], v)
copy(r[i+len(v):], s[j:])
+ clear(s[tot:]) // zero/nil out the obsolete elements, for GC
return r
}
// This is like the uniq command found on Unix.
// Compact modifies the contents of the slice s and returns the modified slice,
// which may have a smaller length.
-// When Compact discards m elements in total, it might not modify the elements
-// s[len(s)-m:len(s)]. If those elements contain pointers you might consider
-// zeroing those elements so that objects they reference can be garbage collected.
+// Compact zeroes the elements between the new length and the original length.
func Compact[S ~[]E, E comparable](s S) S {
if len(s) < 2 {
return s
i++
}
}
+ clear(s[i:]) // zero/nil out the obsolete elements, for GC
return s[:i]
}
// CompactFunc is like [Compact] but uses an equality function to compare elements.
// 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) < 2 {
return s
i++
}
}
+ clear(s[i:]) // zero/nil out the obsolete elements, for GC
return s[:i]
}