bb/cat/cat.go
2019-10-30 04:54:45 +05:00

70 lines
No EOL
1.2 KiB
Go

package cat
/* Simple module to get output of a few files
* and put in in one only. */
import(
"os"
"io"
"log"
"flag"
)
type Catter struct {
warn *log.Logger
out *os.File
bufSiz int
buf []byte
}
func New(out *os.File, warn *log.Logger, bufSiz int) *Catter {
c := new(Catter)
c.out = out
c.warn = warn
c.bufSiz = bufSiz
c.buf = make([]byte, c.bufSiz)
return c
}
func (c Catter) Cat(files []*os.File) error {
for _, file := range files {
for {
n, err := file.Read(c.buf)
if n>0 {
_, err := c.out.Write(c.buf[:n])
if err != nil {
return err
}
}
if err == io.EOF {
break
}else if err != nil {
c.warn.Println(err)
}
}
}
return nil
}
func (c Catter)OpenArr(filePaths []string) []*os.File {
files := make([]*os.File, len(filePaths))
for i, filePath := range filePaths {
var err error
files[i], err = os.Open(filePath)
if err != nil {
c.warn.Println(err)
}
}
return files
}
func Run(args []string) int {
flagSet := flag.NewFlagSet(args[0], flag.ExitOnError)
flagSet.Parse(args[1:])
status := 0
warn := log.New(os.Stderr, args[0]+": ", 0)
c := New(os.Stdout, warn, 512)
files := c.OpenArr(flagSet.Args())
err := c.Cat(files)
if err != nil {
status = 1
}
return status
}