提一个关于切片扩容的问题

#### 先贴一下growslice的源码 newcap := old.cap doublecap := newcap + newcap if cap > doublecap { newcap = cap } else { if old.len < 1024 { newcap = doublecap } else { // Check 0 < newcap to detect overflow // and prevent an infinite loop. for 0 < newcap && newcap < cap { newcap += newcap / 4 } // Set newcap to the requested cap when // the newcap calculation overflowed. if newcap <= 0 { newcap = cap } } 对于切片长度小于1024时，没有疑问，但是当大于1024或等于1024时和预期的结果不一样，希望可以解答一下 #### 贴一下我的测试代码 s7 := make([]int, 1024) fmt.Printf("The capacity of s7: %d\n", cap(s7)) s7e1 := append(s7, make([]int, 200)...) fmt.Printf("s7e1: len: %d, cap: %d\n", len(s7e1), cap(s7e1)) s7e2 := append(s7, make([]int, 400)...) fmt.Printf("s7e2: len: %d, cap: %d\n", len(s7e2), cap(s7e2)) s7e3 := append(s7, make([]int, 600)...) fmt.Printf("s7e3: len: %d, cap: %d\n", len(s7e3), cap(s7e3)) fmt.Println() 实际运行结果： The capacity of s7: 1024 s7e1: len: 1224, cap: 1280 s7e2: len: 1424, cap: 1696 s7e3: len: 1624, cap: 2048 预期运行结果： The capacity of s7: 1024 s7e1: len: 1224, cap: 1280 s7e2: len: 1424, cap: 1600 s7e3: len: 1624, cap: 2000 同时，当新切片长度比原容量2倍还大时的扩容机制有些不解，希望可以帮忙解答一下，谢谢 #### 同样，这里贴一下代码 s8 := make([]int, 10) fmt.Printf("The capacity of s8: %d\n", cap(s8)) s8a := append(s8, make([]int, 11)...) fmt.Printf("s8a: len: %d, cap: %d\n", len(s8a), cap(s8a)) s8b := append(s8a, make([]int, 23)...) fmt.Printf("s8b: len: %d, cap: %d\n", len(s8b), cap(s8b)) s8c := append(s8b, make([]int, 45)...) fmt.Printf("s8c: len: %d, cap: %d\n", len(s8c), cap(s8c)) 实际运行结果： The capacity of s8: 10 s8a: len: 21, cap: 22 s8b: len: 44, cap: 44 s8c: len: 89, cap: 96 预期运行结果： The capacity of s8: 10 s8a: len: 21, cap: 21 s8b: len: 44, cap: 44 s8c: len: 89, cap: 89