go语言中slice,map,channl底层原理

var sli []int
sli = make([]int, len, cap) // cap可以省略

//或者
sli := make([]int, len, cap) // cap可以省略

arr := []int{1,2,3,4,5}
sli := arr[sta:end:cap] // :cap可以省略，以这种方式创建的sli，其cap为sta到arr的最后一位

type {
    array unsafe.Pointer // 指针
    len int // 现有长度
    cap int // 容量 
}

m = make(map[int]int) // 需要注意 make(map)返回的是一个指针 

type hmap {
    count int
    flags uint8 // map当前是否处于写入状态等
    B     uint8 // 2的B次幂表示当前map中桶的数量（buckets的长度）
    noverlow uint16 // map中溢出桶的数量，当溢出桶太多时，map会进行等量扩容
    hash0 uint32 //生成hash的随机数种子
    
    buckets unsafe.Pointer //当前map对应的桶的指针
    oldbuckets unsafe.Pointer // 扩容时的旧桶
    nevacuate uintptr //扩容时，用于标记当前旧桶中小于nevacute的数据都已经转移到了新桶
    
    extra *mapextra //存储map的溢出桶
}

type hchan struct {
    qcount   uint           // total data in the queue
    dataqsiz uint           // size of the circular queue
    buf      unsafe.Pointer // points to an array of dataqsiz elements
    elemsize uint16
    closed   uint32
    elemtype *_type // element type
    sendx    uint   // send index
    recvx    uint   // receive index
    recvq    waitq  // list of recv waiters
    sendq    waitq  // list of send waiters

    // lock protects all fields in hchan, as well as several
    // fields in sudogs blocked on this channel.
    //
    // Do not change another G's status while holding this lock
    // (in particular, do not ready a G), as this can deadlock
    // with stack shrinking.
    lock mutex
}