package util

import (
	"io"
	"reflect"
	"unsafe"
)

func WriteFull(writer io.Writer, buf []byte) error {
	total := len(buf)
	for pos := 0; pos < total; {
		n, err := writer.Write(buf[pos:])
		if err != nil {
			return err
		}
		pos += n
	}
	return nil
}

func String2Bytes(s string) []byte {
	stringHeader := (*reflect.StringHeader)(unsafe.Pointer(&s))
	bh := reflect.SliceHeader{
		Data: stringHeader.Data,
		Len:  stringHeader.Len,
		Cap:  stringHeader.Len,
	}
	return *(*[]byte)(unsafe.Pointer(&bh))
}

func Bytes2String(b []byte) string {
	sliceHeader := (*reflect.SliceHeader)(unsafe.Pointer(&b))
	sh := reflect.StringHeader{
		Data: sliceHeader.Data,
		Len:  sliceHeader.Len,
	}
	return *(*string)(unsafe.Pointer(&sh))
}