From bd0231bf42e62e3497f403222cb9271c52e76f81 Mon Sep 17 00:00:00 2001
From: qydysky <qydysky@foxmail.com>
Date: Sun, 16 Jun 2024 02:55:28 +0000
Subject: [PATCH] slices.Resize

---
 slice/Slice.go      |  8 ++++++++
 slice/Slice_test.go | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+)

diff --git a/slice/Slice.go b/slice/Slice.go
index 5d7cceb..78c4589 100644
--- a/slice/Slice.go
+++ b/slice/Slice.go
@@ -221,3 +221,11 @@ func DelBack[S ~[]T, T any](s *S, fromIndex int) {
 func AddBack[S ~[]*T, T any](s *S, t *T) {
 	*s = append(*s, t)
 }
+
+func Resize[S ~[]T, T any](s *S, size int) {
+	if len(*s) >= size || cap(*s) >= size {
+		*s = (*s)[:size]
+	} else {
+		*s = append((*s)[:cap(*s)], make([]T, size-cap(*s))...)
+	}
+}
diff --git a/slice/Slice_test.go b/slice/Slice_test.go
index fc86d8d..bb33187 100644
--- a/slice/Slice_test.go
+++ b/slice/Slice_test.go
@@ -6,6 +6,38 @@ import (
 	"unsafe"
 )
 
+func TestResize(t *testing.T) {
+	var s = make([]byte, 10)
+	t.Log(unsafe.Pointer(&s), len(s), cap(s))
+	s = s[:0]
+	t.Log(unsafe.Pointer(&s), len(s), cap(s))
+	Resize(&s, 8)
+	if len(s) != 8 {
+		t.FailNow()
+	}
+	t.Log(unsafe.Pointer(&s), len(s), cap(s))
+	Resize(&s, 4)
+	if len(s) != 4 {
+		t.FailNow()
+	}
+	t.Log(unsafe.Pointer(&s), len(s), cap(s))
+	Resize(&s, 11)
+	if len(s) != 11 {
+		t.FailNow()
+	}
+	t.Log(unsafe.Pointer(&s), len(s), cap(s))
+	Resize(&s, 25)
+	if len(s) != 25 {
+		t.FailNow()
+	}
+	t.Log(unsafe.Pointer(&s), len(s), cap(s))
+	Resize(&s, 3)
+	if len(s) != 3 {
+		t.FailNow()
+	}
+	t.Log(unsafe.Pointer(&s), len(s), cap(s))
+}
+
 func TestXxx(t *testing.T) {
 	var (
 		b = New[byte](5)
-- 
2.39.2