Emacs: Binary File Viewer

 

Quick visualization tool for Binary data using C header definition.

1. Semantic parses the C header file and generates a type definition.
2. The type definition is passed to bindat-unpack along with the binary data.
3. The result is displayed using speedbar.

;; Note: The command works on the binary data in the current buffer.

 

M-x hexl-form

 

(hexl-form)

  

 

The image shows the example included in the commentary section of bindat.el.

 

Conversions

(format "%02X" 255) ;; => "FF"
(string-to-number "FF" 16) ;; => 255

 

;; Little endian unpacking

(let* ((bindat-raw [1 2 3 4 5 6 7 8])
          (bindat-idx 0))
  (bindat--unpack-u64r))

 

;; Little endian packing

(let* ((bindat-raw [0 0 0 0 0 0 0 0])
          (bindat-idx 0))
  (bindat--pack-u64r #x0102030405060708)
  bindat-raw)

  

 

Insert Binary Data

Emacs creates a multibyte buffer by default. While working with binary file (not in hexl-mode), this must be disabled.

(set-buffer-multibyte nil)
(insert 192) ; c0

(setq binary-data
      [ 192 168 1 100 192 168 1 101 01 28 21 32 2 0 0 0
        2 3 0 5 ?A ?B ?C ?D ?E ?F 0 0 1 2 3 4 5 0 0 0
        1 4 0 7 ?B ?C ?D ?E ?F ?G 0 0 6 7 8 9 10 11 12 0 ])

(mapc 'insert binary-data)
  

Code: https://gitlab.com/atamariya/emacs/-/blob/dev/lisp/hexl.el

 

Usage

Disk Partition Table

 

 

References

1. Sanitize vector unpacking
2. Little Endian bindat-type usage documentation
   
3. Disk partition definitions
4. Binary patching (xxd)
5. Binary File I/O (dd)