固定字节切片到字符串的转换-忽略null

Question

Is there is efficient way to convert a fixed byte slice to a string without adding null characters to the string?

The traditional way to convert a string from a byte slice is the following:

out := string(b[STRIDX:STRIDX+STRLEN]) 

While this returns a string, the length is always equal to the byte slice length. So while the string looks normal on a Print statement it is still referencing potentiality null values.This has some very odd effects if you append characters to this string.

Right now i scan the byte slice for nulls to limit the byte slice i feed to string. Not very pretty or efficient.

Example: https://play.golang.org/p/hOoaqCOoFl0

Answer 1

Write a simple function:

func CToGoString(b []byte) string {
    i := bytes.IndexByte(b, 0)
    if i < 0 {
        i = len(b)
    }
    return string(b[:i])
}

For your example,

package main

import (
    "bytes"
    "fmt"
)

func CToGoString(b []byte) string {
    i := bytes.IndexByte(b, 0)
    if i < 0 {
        i = len(b)
    }
    return string(b[:i])
}

const (
    BUFLEN = 50
    STRLEN = 10
    STRIDX = 10
)

func main() {
    test := "test"
    b := [BUFLEN]byte{}
    fmt.Printf("Original
\tString: '%+v' with length '%d'
", test, len(test))

    copy(b[10:], []byte(test))

    s := CToGoString(b[STRIDX : STRIDX+STRLEN])
    fmt.Printf("Unpacking with []byte()
\tString: '%+v' with length '%d' Buf:%+v
", s, len(s), []byte(s))
}

Playground: https://play.golang.org/p/mH3CBdM6eG_l

Output:

Original
    String: 'test' with length '4'
Unpacking with []byte()
    String: 'test' with length '4' Buf:[116 101 115 116]