Sharing tips on implementing file encoding modification in Golang

How to modify the file encoding? Use ioutil.ReadFile and io.WriteString to read and write files, specifying the new encoding. Use bufio.Reader and bufio.Writer to read and write files line by line and create objects with different encodings. Use the OpenFile function of the os library to specify the encoding when creating or opening a file.

Go language practice: modify the file encoding

In the Go language, the file encoding is a specification for specifying its character set. For different languages ​​and scenarios, it is important to use different encodings to ensure correct display and processing of file content. This article will introduce several common coding modification techniques and provide practical cases.

Method 1: ioutil.ReadFile and io.WriteString

The simplest method is to use ioutil.ReadFile to read the file content and then use io.WriteString Write to the file and specify the new encoding.

package main

import (
    "fmt"
    "io/ioutil"
    "os"
)

func main() {
    oldBytes, err := ioutil.ReadFile("test.txt")
    if err != nil {
        fmt.Println(err)
        return
    }

    newBytes := string(oldBytes)
    err = ioutil.WriteFile("test.txt", []byte(newBytes), 0666)
    if err != nil {
        fmt.Println(err)
        return
    }

    fmt.Println("File encoding changed successfully.")
}

Method 2: bufio.Reader and bufio.Writer

bufio.Reader and bufio.Writer allow pairing Files are read and written line by line. We can create these two objects using different encodings to read and write files.

package main

import (
    "bufio"
    "errors"
    "fmt"
    "io"
    "os"
)

func ReadFileWithEncoding(filePath string, encoding string) (string, error) {
    f, err := os.OpenFile(filePath, os.O_RDWR, 0666)
    if err != nil {
        return "", err
    }
    defer f.Close()

    dec := NewDecoder(f, encoding)
    content, err := dec.ReadString('\n')
    if err != nil {
        if err == io.EOF {
            return "", nil
        }
        return "", err
    }
    return content, nil
}

func NewDecoder(r io.Reader, enc string) (*Decoder, error) {
    switch enc {
    case "utf8":
        return &Decoder{reader: bufio.NewReader(r)}, nil
    case "utf16":
        return &Decoder{reader: bufio.NewReader(r), encoding: unicode.UTF16}, nil
    }
    return nil, errors.New("Unsupported encoding")
}

type Decoder struct {
    reader io.Reader
    encoding binary.ByteOrder
}

func (dec *Decoder) ReadString(delim byte) (string, error) {
    var buf bytes.Buffer
    found := false
    for {
        char, _, err := dec.reader.ReadRune()
        if err != nil {
            return "", err
        }
        if char == delim {
            found = true
            break
        }
        buf.WriteRune(char)
    }
    if !found {
        return "", io.EOF
    }
    return buf.String(), nil
}

func WriteFileWithEncoding(filePath string, content string, encoding string) error {
    f, err := os.OpenFile(filePath, os.O_RDWR|os.O_CREATE, 0666)
    if err != nil {
        return err
    }
    defer f.Close()

    enc := NewEncoder(f, encoding)
    _, err = enc.WriteString(content)
    if err != nil {
        return err
    }
    return nil
}

func NewEncoder(w io.Writer, enc string) (*Encoder, error) {
    switch enc {
    case "utf8":
        return &Encoder{writer: bufio.NewWriter(w)}, nil
    case "utf16":
        return &Encoder{writer: bufio.NewWriter(w), encoding: unicode.UTF16}, nil
    }
    return nil, errors.New("Unsupported encoding")
}

type Encoder struct {
    writer io.Writer
    encoding binary.ByteOrder
}

func (enc *Encoder) WriteString(content string) (int, error) {
    size := len(content)
    for i := 0; i < size; {
        b := make([]byte, 2*len(content))
        n := copy(b, content[i:])
        if n == 0 {
            return 0, errors.New("Empty content")
        }
        i += n
        _, err := enc.writer.Write(b)
        if err != nil {
            return 0, err
        }
    }
    return size, nil
}

func main() {
    content, err := ReadFileWithEncoding("test.txt", "utf8")
    if err != nil {
        fmt.Println(err)
        return
    }

    err = WriteFileWithEncoding("test.txt", content, "utf16")
    if err != nil {
        fmt.Println(err)
        return
    }

    fmt.Println("File encoding changed successfully.")
}

Method 3: os library

os The library provides the OpenFile function, which allows us to create or open Specify the encoding for the file.

package main

import (
    "fmt"
    "os"
)

func main() {
    f, err := os.OpenFile("test.txt", os.O_RDWR|os.O_CREATE, 0666)
    if err != nil {
        fmt.Println(err)
        return
    }

    _, err = f.WriteString("Hello, world!")
    if err != nil {
        fmt.Println(err)
        return
    }

    err = f.Close()
    if err != nil {
        fmt.Println(err)
        return
    }

    fmt.Println("File encoding changed successfully.")
}

Note:

• When modifying the file encoding, ensure that the new encoding is compatible with the file content.
• Please note that some character sets (such as ASCII) can be represented by multiple encodings, so there may be subtle differences when modifying the encoding.

The above is the detailed content of Sharing tips on implementing file encoding modification in Golang. For more information, please follow other related articles on the PHP Chinese website!