How to perform buffered I/O operations with custom buffers and bufio in Go?

To perform buffered I/O operations with custom buffers in Go, you can use the bufio package. Here's how you can do it:

Import the bufio package:

import (
    "bufio"
    "os"
)

Create a custom buffer using the bufio.NewWriterSize function and specify the size of the buffer:

bufferSize := 1024 // Set your desired buffer size
file, err := os.Create("output.txt")
if err != nil {
    panic(err)
}
writer := bufio.NewWriterSize(file, bufferSize)
defer writer.Flush() // Flush the buffer before closing the writer

Write data to the buffer using the writer.Write or writer.WriteString functions:

data := []byte("Hello, World!")
_, err = writer.Write(data)
if err != nil {
    panic(err)
}

If the buffer is full or you want to force flushing the buffer to the underlying writer, use writer.Flush:

writer.Flush()

To read data from a custom buffer, use the bufio.NewReaderSize function in a similar way:

file, err := os.Open("input.txt")
if err != nil {
    panic(err)
}
reader := bufio.NewReaderSize(file, bufferSize)
defer file.Close()

data := make([]byte, bufferSize)
_, err = reader.Read(data)
if err != nil {
    panic(err)
}

Note that you can customize the buffer size according to your needs for optimal performance. Remember to flush the buffer before closing the writer to ensure all data is written. Similarly, ensure to close the file when done reading from it.

That's how you can perform buffered I/O operations with custom buffers using the bufio package in Go.