cat: Code simplified.

cat/cat.go

@@ -1,70 +1,53 @@
 package cat
-/* Simple module to get output of a few files
-  * and put in in one only. */
+/* Concatenate files in "stdout". */
 import(
 	"os"
 	"io"
-	"log"
 	"flag"
+	"fmt"
 )
-type Catter struct {
-	warn *log.Logger
-	out *os.File
-	bufSiz int
-	buf []byte
+
+func cat(p string) error {
+	f, e := os.Open(p)
+	if e != nil {
+		return e
+	}
+	defer f.Close()
+	fcat(f)
+	return nil
 }
 
-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)
-			}
+func fcat(f *os.File) error {
+	b := make([]byte, 512)
+	for {
+		n, e := f.Read(b)
+		if n>0 {
+			fmt.Print(string(b[:n]))
+		}
+		if e == io.EOF {
+			break
+		}else if e != nil {
+			return e
 		}
 	}
 	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 {
+func Run(args []string) int {	
 	flagSet := flag.NewFlagSet(args[0], flag.ExitOnError)
 	flagSet.Parse(args[1:])
+	arg0 := args[0]
+	args = 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
+	if len(args)>0 {
+		for _, p := range args {
+			e := cat(p)
+			if e != nil {
+				fmt.Fprintf(os.Stderr, "%s: %s.\n", arg0, e)
+			}
+		}
+	} else {
+		fcat(os.Stdin)
 	}
 	return status
 }