// Investigating the size of structs in Go
// @author gtowell
// Created: Nov 12, 2021

package main

import (
	"fmt"
	"unsafe"
)

// a basic structure
type s1 struct {
	a1 bool
	a2 string
	a3 bool
}

// struct with same content
// NOT structurally equivalent
type s2 struct {
	a1 bool
	a3 bool
	a2 string
}

// struct with embedded struct (no name on the  field)
type s3 struct {
	*s3
	a1 int16
}

// struct with included struct (it it has its own named field)
type s4 struct {
	s2 s2
	a1 int16
}

func main() {
	var b = true
	var s = "01234567890123456789012345678901234567890123456789"
	fmt.Printf("bool and string:  %d  %d\n", unsafe.Sizeof(b), unsafe.Sizeof(s))

	var as1 = s1{true, "ajkzdhfkusdhfeuridsihfidshfukhdsfkuhsdkufghsdukfhuewru", true}
	var as2 = s2{true, true, "a"}
	fmt.Printf("Struct of 2 bool and 1 string%d %d\n", unsafe.Sizeof(as1), unsafe.Sizeof(as2))

	var as3 s3
	as3.a1 = 30
	as3.s2.a1=true  // the a1 var defined in s2 is not hidden, just awkward to access
	as3.a2 = "hello"
	as3.a3 = true

	fmt.Printf("Struct of embedded struct and int16 %d  %v\n", unsafe.Sizeof(as3), as3)

	var as4 s4
	as4.s2.a2="hello"
	fmt.Printf("Struct of struct and int16 %d  %v\n", unsafe.Sizeof(as4), as4)
}