如何将字节缓冲区中的以空字符结尾的字符串转换为Go中的字符串？

huangapple
go评论136阅读模式
英文:

How can I convert a null-terminated string in a byte buffer to a string in Go?

问题

这个：

  1. label := string([]byte{97, 98, 99, 0, 0, 0, 0})
  2. fmt.Printf("%s\n", label)

变成了这样（^@ 是空字节）：

  1. go run test.go 
  2. abc^@^@^@
英文:

This:

  1. label := string([]byte{97, 98, 99, 0, 0, 0, 0})
  2. fmt.Printf("%s\n", label)

does this (^@ is the null-byte):

  1. go run test.go 
  2. abc^@^@^@

答案1

得分: 16

在Go的syscall包中有一个隐藏的函数，它可以找到第一个空字节([]byte{0})并返回其长度。我假设它被称为clen，表示C长度。

抱歉我回答晚了一年，但我认为这个方法比其他两个方法简单得多（没有不必要的导入等）。

  1. func clen(n []byte) int {
  2.     for i := 0; i < len(n); i++ {
  3.         if n[i] == 0 {
  4.             return i
  5.         }
  6.     }
  7.     return len(n)
  8. }

所以，

  1. label := []byte{97, 98, 99, 0, 0, 0, 0}
  2. s := label[:clen(label)]
  3. fmt.Println(string(s))

上面的代码将s设置为从label的开头到clen(label)索引的字节切片。

结果将是长度为3的abc。

英文:

There's this function hidden inside Go's syscall package that finds the first null byte ([]byte{0}) and returns the length. I'm assuming it's called clen for C-Length.

Sorry I'm a year late on this answer, but I think it's a lot simpler than the other two (no unnecessary imports, etc.)

  1. func clen(n []byte) int {
  2. 	for i := 0; i &lt; len(n); i++ {
  3. 		if n[i] == 0 {
  4. 			return i
  5. 		}
  6. 	}
  7. 	return len(n)
  8. }

So,

  1. label := []byte{97, 98, 99, 0, 0, 0, 0}
  2. s := label[:clen(label)]
  3. fmt.Println(string(s))

What that ^ says is to set s to the slice of bytes in label from the beginning to the index of clen(label).

The result would be abc with a length of 3.

答案2

得分: 12

请注意，第一个答案只适用于在空终止符后只有一串零的字符串；然而，一个正确的C风格的空终止字符串在第一个\0处结束，即使后面跟着垃圾字符。例如，[]byte{97,98,99,0,99,99,0}应该被解析为abc，而不是abc^@cc。

为了正确解析这个字符串，可以使用string.Index函数来找到第一个\0，然后使用它来切片原始的字节切片：

  1. package main
  3. import (
  4.     "fmt"
  5.     "strings"
  6. )
  8. func main() {
  9.     label := []byte{97,98,99,0,99,99,0}
  10.     nullIndex := strings.Index(string(label), "\x00")
  11.     if (nullIndex < 0) {
  12.         fmt.Println("Buffer did not hold a null-terminated string")
  13.         os.Exit(1)
  14.     }
  15.     fmt.Println(string(label[:nullIndex]))
  16. }

编辑：之前将缩短的版本打印为[]byte而不是string。感谢 @serbaut 的指正。

编辑2：之前没有处理缓冲区没有空终止符的错误情况。感谢 @snap 的指正。

英文:

Note that the first answer will only work with strings that have only a run of zeroes after the null terminator; however, a proper C-style null-terminated string ends at the first \0 even if it's followed by garbage. For example, []byte{97,98,99,0,99,99,0} should be parsed as abc, not abc^@cc.

To properly parse this, use string.Index, as follows, to find the first \0 and use it to slice the original byte-slice:

  1. package main
  3. import (
  4.     &quot;fmt&quot;
  5.     &quot;strings&quot;
  6. )
  8. func main() {
  9.     label := []byte{97,98,99,0,99,99,0}
  10.     nullIndex := strings.Index(string(label), &quot;\x00&quot;)
  11.     if (nullIndex &lt; 0) {
  12.         fmt.Println(&quot;Buffer did not hold a null-terminated string&quot;)
  13.         os.Exit(1)
  14.     }
  15.     fmt.Println(string(label[:nullIndex]))
  16. }

EDIT: Was printing the shortened version as a []byte instead of as a string. Thanks to @serbaut for the catch.

EDIT 2: Was not handling the error case of a buffer without a null terminator. Thanks to @snap for the catch.

答案3

得分: 1

你可以使用sys包：

  1. package main
  2. import "golang.org/x/sys/windows"
  4. func main() {
  5.    b := []byte{97, 98, 99, 0, 0, 0, 0}
  6.    s := windows.ByteSliceToString(b)
  7.    println(s == "abc")
  8. }

或者你可以自己实现它：

  1. package main
  2. import "bytes"
  4. func byteSliceToString(s []byte) string {
  5.    n := bytes.IndexByte(s, 0)
  6.    if n >= 0 {
  7.       s = s[:n]
  8.    }
  9.    return string(s)
  10. }
  12. func main() {
  13.    b := []byte{97, 98, 99, 0, 0, 0, 0}
  14.    s := byteSliceToString(b)
  15.    println(s == "abc")
  16. }
英文:

You can use the sys package:

  1. package main
  2. import &quot;golang.org/x/sys/windows&quot;
  4. func main() {
  5.    b := []byte{97, 98, 99, 0, 0, 0, 0}
  6.    s := windows.ByteSliceToString(b)
  7.    println(s == &quot;abc&quot;)
  8. }

Or you can just implement it yourself:

  1. package main
  2. import &quot;bytes&quot;
  4. func byteSliceToString(s []byte) string {
  5.    n := bytes.IndexByte(s, 0)
  6.    if n &gt;= 0 {
  7.       s = s[:n]
  8.    }
  9.    return string(s)
  10. }
  12. func main() {
  13.    b := []byte{97, 98, 99, 0, 0, 0, 0}
  14.    s := byteSliceToString(b)
  15.    println(s == &quot;abc&quot;)
  16. }

答案4

得分: 1

1. strings.TrimSpace .TrimRight

//trim tail '\0', but can't handle bytes like "abc\x00def\x00".

can't edit @orelli answer, so wrote here:

  1. package main
  3. import (
  4.     "fmt"
  5.     "strings"
  6. )
  8. func main() {
  9.     label := string([]byte{97, 98, 99, 0, 0, 0, 0})
  11.     s1 := strings.TrimSpace(label)
  12.     fmt.Println(len(s1), s1)
  14.     s2 := strings.TrimRight(label, "\x00")
  15.     fmt.Println(len(s2), s2)
  16.   }

output:

  1. 7 abc????
  2. 3 abc

// ? is '\0' which can't display here.

<br>

So
.TrimSpace can't trim '\0', but
.TrimRight with "\x00" can.

<br><br>

2. bytes.IndexByte

search for first '\0', maybe not support utf-8

  1. package main
  3. import (
  4. 	"bytes"
  5. 	"fmt"
  6. 	"strings"
  7. )
  9. func main() {
  10. 	b_arr := []byte{97, 98, 99, 0, 100, 0, 0}
  11. 	label := string(b_arr)
  13. 	s1 := strings.TrimSpace(label)
  14. 	fmt.Println(len(s1), s1)   //7 abc?d??
  16. 	s2 := strings.TrimRight(label, "\x00")
  17. 	fmt.Println(len(s2), s2)   //5 abc?d
  19. 	n := bytes.IndexByte([]byte(label), 0)
  20. 	fmt.Println(n, label[:n])  //3 abc
  22. 	s_arr := b_arr[:bytes.IndexByte(b_arr, 0)]
  23. 	fmt.Println(len(s_arr), string(s_arr)) //3 abc
  24. }

equivalent

  1. n1 := bytes.IndexByte(b_arr, 0)
  2. n2 := bytes.Index(b_arr, []byte{0})
  4. n3, c := 0, byte(0)
  5. for n3, c = range b_arr {
  6. 	if c == 0 {
  7. 		break
  8. 	}
  9. }
英文:

1. strings <del>.TrimSpace</del> .TrimRight

//trim tail '\0', but can't handle bytes like "abc\x00def\x00".

can't edit @orelli answer, so wrote here:

  1. package main
  3. import (
  4.     &quot;fmt&quot;
  5.     &quot;strings&quot;
  6. )
  8. func main() {
  9.     label := string([]byte{97, 98, 99, 0, 0, 0, 0})
  11.     s1 := strings.TrimSpace(label)
  12.     fmt.Println(len(s1), s1)
  14.     s2 := strings.TrimRight(label, &quot;\x00&quot;)
  15.     fmt.Println(len(s2), s2)
  16.   }

output:

  1. 7 abc????
  2. 3 abc

// ? is '\0' which can't display here.

<br>

So
.TrimSpace can't trim '\0', but
.TrimRight with "\x00" can.

<br><br>

2. bytes.IndexByte

search for first '\0', maybe not support utf-8

  1. package main
  3. import (
  4. 	&quot;bytes&quot;
  5. 	&quot;fmt&quot;
  6. 	&quot;strings&quot;
  7. )
  9. func main() {
  10. 	b_arr := []byte{97, 98, 99, 0, 100, 0, 0}
  11. 	label := string(b_arr)
  13. 	s1 := strings.TrimSpace(label)
  14. 	fmt.Println(len(s1), s1)   //7 abc?d??
  16. 	s2 := strings.TrimRight(label, &quot;\x00&quot;)
  17. 	fmt.Println(len(s2), s2)   //5 abc?d
  19. 	n := bytes.IndexByte([]byte(label), 0)
  20. 	fmt.Println(n, label[:n])  //3 abc
  22. 	s_arr := b_arr[:bytes.IndexByte(b_arr, 0)]
  23. 	fmt.Println(len(s_arr), string(s_arr)) //3 abc
  24. }

equivalent

  1. n1 := bytes.IndexByte(b_arr, 0)
  2. n2 := bytes.Index(b_arr, []byte{0})
  4. n3, c := 0, byte(0)
  5. for n3, c = range b_arr {
  6. 	if c == 0 {
  7. 		break
  8. 	}
  9. }

答案5

得分: 0

你可以使用bytes.SplitN并让它返回第一个子切片：

  1. import (
  2. 	"bytes"
  3. )
  5. func bytesToStr(in []byte) string {
  6. 	str := bytes.SplitN(in, []byte{0}, 2)[0]
  7. 	return string(str)
  8. }

在Go 1.18+中，你也可以使用bytes.Cut：

  1. func bytesToStr(in []byte) string {
  2. 	str, _, _ := bytes.Cut(in, []byte{0})
  3. 	return string(str)
  4. }
英文:

You can use bytes.SplitN and have it return the first subslice:

  1. import (
  2. 	&quot;bytes&quot;
  3. )
  5. func bytesToStr(in []byte) string {
  6. 	str := bytes.SplitN(in, []byte{0}, 2)[0]
  7. 	return string(str)
  8. }

In go 1.18+, you can also use bytes.Cut:

  1. func bytesToStr(in []byte) string {
  2. 	str, _, _ := bytes.Cut(in, []byte{0})
  3. 	return string(str)
  4. }

huangapple
  • 本文由 发表于 2012年9月11日 05:30:56
  • 转载请务必保留本文链接：https://go.coder-hub.com/12359777.html
  • c
  • go
  • string
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