Go bufio Detailed Explanation

Detailed Explanation of the Bufio Package#

The bufio package is a package in the Go standard library that provides buffered I/O operations to improve I/O efficiency. It encapsulates io.Reader and io.Writer and provides buffering capabilities to reduce the number of system calls and improve read and write performance.

Here is a detailed introduction to the bufio package and some examples:

Creating a buffered reader (Scanner):

The NewScanner() function is used to create a buffered reader that reads data from the specified io.Reader.
The Scanner type provides convenient methods for reading data line by line or word by word.

Example:

file, _ := os.Open("data.txt")
scanner := bufio.NewScanner(file)

for scanner.Scan() {
    line := scanner.Text()
    fmt.Println(line)
}

if err := scanner.Err(); err != nil {
    fmt.Println("Error:", err)
}

Creating a buffered writer (Writer):
- The NewWriter() function is used to create a buffered writer that writes data to the specified io.Writer.
- The Writer type provides the Write() method, which is used to write data to the buffer and write the data to the underlying io.Writer when the buffer is full or explicitly flushed.
- Example:
```
file, _ := os.Create("output.txt")
writer := bufio.NewWriter(file)

text := "Hello, World!"
writer.WriteString(text)
writer.Flush() // Flush the buffer to ensure all data is written to the underlying file

file.Close()
```

Creating a buffered reader (Reader):

The NewReader() function is used to create a buffered reader that reads data from the specified io.Reader and provides buffering mechanism.
The Reader type provides the Read() method, which is used to read data from the buffer and fill the buffer when it is empty.

Example:

data := []byte("Hello, World!")
reader := bufio.NewReader(bytes.NewReader(data))

buffer := make([]byte, 5)
for {
    n, err := reader.Read(buffer)
    if err != nil && err != io.EOF {
        fmt.Println("Error:", err)
        break
    }

    if n == 0 {
        break
    }

    fmt.Println(string(buffer[:n]))
}

The bufio package also provides other functions and types, such as ReadString(), WriteString(), delimiter setting for Scanner, and more advanced buffered writers. These features can help you perform I/O operations more efficiently.

Please note that after using a buffered reader or buffered writer, be sure to call the Flush() method of Scanner, Writer, or Reader to ensure that all data is written or read.

This is a brief introduction and examples of the bufio package. Using the bufio package can improve the efficiency of I/O operations and simplify input and output handling. If you have any further questions, please feel free to ask.