Add width parameter

main.go

@@ -25,7 +25,7 @@ const (
 )
 
 // Parse command line arguments
-func getParams() (source iface.ReadSeekerCloser, displays []reader.ByteFormatter, offsetViewer []reader.OffsetFormatter, limit uint64, palette [256]color.AnsiColor, filesize int64) {
+func getParams() (source iface.ReadSeekerCloser, displays []reader.ByteFormatter, offsetViewer []reader.OffsetFormatter, limit uint64, palette [256]color.AnsiColor, filesize int64, width uint16) {
 	opt := getoptions.New()
 
 	opt.HelpSynopsisArgs(`<filename> or STDIN`)
@@ -67,14 +67,20 @@ func getParams() (source iface.ReadSeekerCloser, displays []reader.ByteFormatter
 		opt.Description(`Start reading from certain offset. See NOTES.`),
 	)
 
+	argWidth := opt.StringOptional(`width`, `16`,
+		opt.Alias("w"),
+		opt.ArgName(`[prefix]width`),
+		opt.Description(`Width. See NOTES.`),
+	)
+
 	remainingArgs, err := opt.Parse(os.Args[1:])
 
 	if opt.Called("help") {
 		_, _ = fmt.Fprintf(os.Stdout, `heksa - hex file dumper %v - (%v)`+"\n", VERSION, BUILDDATE)
 		_, _ = fmt.Fprintf(os.Stdout, `(c) %v 2019- [ %v ]`+"\n", AUTHOR, HOMEPAGE)
 		_, _ = fmt.Fprintln(os.Stdout, opt.Help())
 		_, _ = fmt.Fprintln(os.Stdout, `NOTES:`)
-		_, _ = fmt.Fprintln(os.Stdout, `    - You can use prefixes for seek and limit. 0x = hex, 0b = binary, 0o = octal`)
+		_, _ = fmt.Fprintln(os.Stdout, `    - You can use prefixes for seek, limit and width. 0x = hex, 0b = binary, 0o = octal`)
 		_, _ = fmt.Fprintln(os.Stdout, `    - Use 'no' or '' for offset formatter for disabling offset output`)
 		_, _ = fmt.Fprintln(os.Stdout, `    - Use '--seek \-1234' for seeking from end of file`)
 		_, _ = fmt.Fprintln(os.Stdout, `    - Limit and seek parameters supports units (KB, KiB, MB, MiB, GB, GiB, TB, TiB)`)
@@ -87,6 +93,7 @@ func getParams() (source iface.ReadSeekerCloser, displays []reader.ByteFormatter
 		_, _ = fmt.Fprintln(os.Stdout, `    heksa -l 0x1024 foo.dat`)
 		_, _ = fmt.Fprintln(os.Stdout, `    heksa -s 0b1010 foo.dat`)
 		_, _ = fmt.Fprintln(os.Stdout, `    heksa -s 4321KiB foo.dat`)
+		_, _ = fmt.Fprintln(os.Stdout, `    heksa -w 8 foo.dat`)
 		os.Exit(0)
 	} else if opt.Called("version") {
 		_, _ = fmt.Fprintf(os.Stdout, `%v build %v on %v`+"\n", VERSION, BUILD, BUILDDATE)
@@ -112,6 +119,17 @@ func getParams() (source iface.ReadSeekerCloser, displays []reader.ByteFormatter
 		os.Exit(1)
 	}
 
+	widthTmp, err := units.Parse(*argWidth)
+	if err != nil {
+		_, _ = fmt.Fprintf(os.Stderr, `error parsing width: %v`, err)
+		os.Exit(1)
+	}
+	width = uint16(widthTmp)
+	if width == 0 {
+		_, _ = fmt.Fprint(os.Stderr, `width must be > 0`)
+		os.Exit(1)
+	}
+
 	offsetViewer, err = reader.GetOffsetFormatters(strings.Split(*argOffset, `,`))
 	if err != nil {
 		_, _ = fmt.Fprintf(os.Stderr, `error getting offset formatter: %v`, err)
@@ -173,16 +191,16 @@ func getParams() (source iface.ReadSeekerCloser, displays []reader.ByteFormatter
 		source = fhandle
 	}
 
-	return source, displays, offsetViewer, limit, palette, filesize
+	return source, displays, offsetViewer, limit, palette, filesize, width
 }
 
 func main() {
-	source, displays, offViewer, limit, palette, filesize := getParams()
+	source, displays, offViewer, limit, palette, filesize, width := getParams()
 
 	stop := make(chan os.Signal, 1)
 	signal.Notify(stop, os.Interrupt)
 
-	r := reader.New(source, offViewer, displays, palette, filesize)
+	r := reader.New(source, offViewer, displays, palette, width, filesize)
 
 	isEven := false
 	// Dump hex

pkg/reader/reader.go

@@ -32,13 +32,19 @@ type Reader struct {
 	offsetFormatterWidth  map[OffsetFormatter]int    // How much padding width needed, calculated from fileSize variable
 	Colors                Colors                     // Colors
 	growHint              int                        // Grow hint for sb strings.Builder variable for speed
+	width                 int                        // Width
+	visualSplitterSize    int                        // Size of visual splitter (2 = XX XX XX, 3 = XXX XXX XXX, etc)
 }
 
-func New(r iface.ReadSeekerCloser, offsetFormatter []OffsetFormatter, formatters []ByteFormatter, palette [256]color.AnsiColor, filesize int64) *Reader {
+func New(r iface.ReadSeekerCloser, offsetFormatter []OffsetFormatter, formatters []ByteFormatter, palette [256]color.AnsiColor, width uint16, filesize int64) *Reader {
 	if formatters == nil {
 		panic(`nil formatter`)
 	}
 
+	if width == 0 {
+		panic(`zero width`)
+	}
+
 	var calcpalette [256]string
 
 	for idx := range palette {
@@ -47,6 +53,8 @@ func New(r iface.ReadSeekerCloser, offsetFormatter []OffsetFormatter, formatters
 
 	reader := &Reader{
 		r:                    r,
+		visualSplitterSize:   8, // Insert extra space after every N bytes
+		width:                int(width),
 		fileSize:             filesize,
 		charFormatters:       formatters,
 		offsetFormatter:      offsetFormatter,
@@ -152,7 +160,7 @@ func (r *Reader) getoffsetRight(offset uint64) string {
 	return r.sb.String()
 }
 
-// Read reads 16 bytes and provides string to display
+// Read reads N (r.width) bytes and provides string to display
 func (r *Reader) Read() (string, error) {
 	var offset uint64
 
@@ -176,7 +184,7 @@ func (r *Reader) Read() (string, error) {
 
 	r.sb.WriteString(offsetLeft)
 
-	tmp := make([]byte, 16)
+	tmp := make([]byte, r.width)
 	rb, err := r.r.Read(tmp)
 	if err != nil {
 		return ``, err
@@ -187,8 +195,8 @@ func (r *Reader) Read() (string, error) {
 	// iterate through every formatter which outputs it's own format
 	for didx, byteFormatterType := range r.charFormatters {
 
-		for i := 0; i < 16; i++ {
-			if i == 8 {
+		for i := 0; i < r.width; i++ {
+			if i > 0 && i%r.visualSplitterSize == 0 {
 				// Add pad for better visualization
 				r.sb.WriteString(` `)
 			}