diff options
Diffstat (limited to 'lisp/emacs-lisp/bindat.el')
| -rw-r--r-- | lisp/emacs-lisp/bindat.el | 44 |
1 files changed, 22 insertions, 22 deletions
diff --git a/lisp/emacs-lisp/bindat.el b/lisp/emacs-lisp/bindat.el index 46040da8d92..312d4b386b3 100644 --- a/lisp/emacs-lisp/bindat.el +++ b/lisp/emacs-lisp/bindat.el @@ -33,22 +33,22 @@ ;; and encoding binary data formats like these is made simple using a ;; structure specification which closely resembles the C style ;; structure declarations. -;; +;; ;; Encoded (binary) data is stored in a unibyte string or vector, -;; while the decoded data is stored in an alist with (FIELD . VALUE) +;; while the decoded data is stored in an alist with (FIELD . VALUE) ;; pairs. ;; Example: - + ;; Consider the following C structures: -;; +;; ;; struct header { ;; unsigned long dest_ip; ;; unsigned long src_ip; ;; unsigned short dest_port; ;; unsigned short src_port; ;; }; -;; +;; ;; struct data { ;; unsigned char type; ;; unsigned char opcode; @@ -56,22 +56,22 @@ ;; unsigned char id[8]; /* nul-terminated string */ ;; unsigned char data[/* (length + 3) & ~3 */]; ;; }; -;; +;; ;; struct packet { ;; struct header header; ;; unsigned char items; ;; unsigned char filler[3]; ;; struct data item[/* items */]; ;; }; -;; +;; ;; The corresponding Lisp bindat specification looks like this: -;; +;; ;; (setq header-spec ;; '((dest-ip ip) ;; (src-ip ip) ;; (dest-port u16) ;; (src-port u16))) -;; +;; ;; (setq data-spec ;; '((type u8) ;; (opcode u8) @@ -79,20 +79,20 @@ ;; (id strz 8) ;; (data vec (length)) ;; (align 4))) -;; +;; ;; (setq packet-spec ;; '((header struct header-spec) ;; (items u8) ;; (fill 3) ;; (item repeat (items) ;; ((struct data-spec))))) -;; +;; ;; ;; A binary data representation may look like -;; [ 192 168 1 100 192 168 1 101 01 28 21 32 2 0 0 0 +;; [ 192 168 1 100 192 168 1 101 01 28 21 32 2 0 0 0 ;; 2 3 5 0 ?A ?B ?C ?D ?E ?F 0 0 1 2 3 4 5 0 0 0 ;; 1 4 7 0 ?B ?C ?D ?E ?F ?G 0 0 6 7 8 9 10 11 12 0 ] -;; +;; ;; The corresponding decoded structure looks like ;; ;; ((header @@ -176,7 +176,7 @@ ;; A `union' specification ;; ([FIELD] union TAG_VAL (TAG SPEC) ... [(t SPEC)]) -;; is interpreted by evalling TAG_VAL and then comparing that to +;; is interpreted by evalling TAG_VAL and then comparing that to ;; each TAG using equal; if a match is found, the corresponding SPEC ;; is used. ;; If TAG is a form (eval EXPR), EXPR is evalled with `tag' bound to the @@ -204,7 +204,7 @@ (string-to-char (substring raw-data pos (1+ pos))) (aref raw-data pos)) (setq pos (1+ pos)))) - + (defun bindat--unpack-u16 () (let* ((a (bindat--unpack-u8)) (b (bindat--unpack-u8))) (logior (lsh a 8) b))) @@ -341,7 +341,7 @@ (setq struct (cons (cons field data) struct)) (setq struct (append data struct)))))) struct)) - + (defun bindat-unpack (spec raw-data &optional pos) "Return structured data according to SPEC for binary data in RAW-DATA. RAW-DATA is a string or vector. Optional third arg POS specifies the @@ -365,7 +365,7 @@ e.g. corresponding to STRUCT.FIELD1[INDEX2].FIELD3..." struct) -;; Calculate raw-data length of structured data +;; Calculate raw-data length of structured data (defvar bindat--fixed-length-alist '((u8 . 1) (byte . 1) @@ -398,7 +398,7 @@ e.g. corresponding to STRUCT.FIELD1[INDEX2].FIELD3..." (setq len (apply 'bindat-get-field struct len))) (if (not len) (setq len 1)) - (cond + (cond ((eq type 'eval) (if field (setq struct (cons (cons field (eval len)) struct)) @@ -446,7 +446,7 @@ e.g. corresponding to STRUCT.FIELD1[INDEX2].FIELD3..." (defun bindat--pack-u8 (v) (aset raw-data pos (logand v 255)) (setq pos (1+ pos))) - + (defun bindat--pack-u16 (v) (aset raw-data pos (logand (lsh v -8) 255)) (aset raw-data (1+ pos) (logand v 255)) @@ -513,7 +513,7 @@ e.g. corresponding to STRUCT.FIELD1[INDEX2].FIELD3..." (aset raw-data (+ pos i) (aref v i)) (setq i (1+ i))) (setq pos (+ pos len)))) - (t + (t (setq pos (+ pos len))))) (defun bindat--pack-group (struct spec) @@ -540,7 +540,7 @@ e.g. corresponding to STRUCT.FIELD1[INDEX2].FIELD3..." (setq len (apply 'bindat-get-field struct len))) (if (not len) (setq len 1)) - (cond + (cond ((eq type 'eval) (if field (setq struct (cons (cons field (eval len)) struct)) @@ -601,7 +601,7 @@ only that many elements from VECT." (setq i (1- i) s (cons (format (if (= i 0) fmt fmt2) (aref vect i)) s))) (apply 'concat s))) - + (defun bindat-vector-to-dec (vect &optional sep) "Format vector VECT in decimal format separated by dots. If optional second arg SEP is a string, use that as separator." |