SoFunction
Updated on 2025-03-05

How to split files according to the specified block size in go language


import (
 // "bufio"
 "flag"
 "fmt"
 "io"
 "os"
)
import "strconv"
var infile *string = ("f", "Null", "please input a file name or dir.")
var size *string = ("s", "0", "please input a dst file size.")
//func dataCopy(file *, file *)
func SplitFile(file *, size int) {
 finfo, err := ()
 if err != nil {
  ("get file info failed:", file, size)
 }
 (finfo, size)
//Copy up to 1m per time
 bufsize := 1024 * 1024
 if size < bufsize {
  bufsize = size
 }
 buf := make([]byte, bufsize)
 num := (int(()) + size - 1) / size
 (num, len(buf))
 for i := 0; i < num; i++ {
  copylen := 0
  newfilename := () + (i)
  newfile, err1 := (newfilename)
  if err1 != nil {
   ("failed to create file", newfilename)
  } else {
   ("create file:", newfilename)
  }
  for copylen < size {
   n, err2 := (buf)
   if err2 != nil && err2 != {
    (err2, "failed to read from:", file)
    break
   }
   if n <= 0 {
    break
   }
   //(n, len(buf))
//Write a file
   w_buf := buf[:n]
   (w_buf)
   copylen += n
  }
 }
 return
}
func main() {
 ()
 if *infile == "Null" {
  ("no file to input")
  return
 }
 file, err := (*infile)
 if err != nil {
  ("failed to open:", *infile)
 }
 defer ()
 size, _ := (*size)
 SplitFile(file, size*1024)
}