From 99e5d85621eb3b7153da9c7c46c3ab39f5d99f1f Mon Sep 17 00:00:00 2001
From: Yves Fischer <yvesf-git@xapek.org>
Date: Sun, 26 Feb 2012 00:34:47 +0100
Subject: ebus-racket: fix payload escaping issue

---
 ebus-racket/parse.rkt | 40 +++++++++++++++++++++++++---------------
 1 file changed, 25 insertions(+), 15 deletions(-)

(limited to 'ebus-racket/parse.rkt')

diff --git a/ebus-racket/parse.rkt b/ebus-racket/parse.rkt
index 46d91fd..dcc749c 100644
--- a/ebus-racket/parse.rkt
+++ b/ebus-racket/parse.rkt
@@ -31,12 +31,12 @@
                                                            primaryCommand
                                                            secondaryCommand
                                                            payloadLength)) )))
-;; 1 payload data byte 
-(define ebus-payload (choice (seq ebus-const-escape 
-                                  escape-code <- (byte-in (list #"\0" #"\1"))
+;; single, maybe escaped, payload data byte 
+(define ebus-payload (choice (seq escape-seq <- (bytes= ebus-const-escape)
+                                  escape-code <- (byte-in (list 0 1))
                                   (return (cond
-                                            ((= escape-code #"\0") ebus-const-escape)
-                                            ((= escape-code #"\0") ebus-const-syn))))
+                                            ((= escape-code 0) ebus-const-escape)
+                                            ((= escape-code 1) ebus-const-syn))))
                              any-byte
                              ))
 
@@ -69,26 +69,36 @@
 (define ebus-sync (tokens syncs <- (seq (repeat (string->bytes/latin-1 "\xaa")))
                           (return (length syncs))))
 
-(define input-port (open-input-file "../doc/dumps/dump_2011-12-17_23-04-00.bin"))
 
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
-(define (read-ebus)
+(define (read-ebus input-port)
   (let ([syn   ((make-reader ebus-sync #:sof? #f #:eof? #f)  input-port)]
         [paket   ((make-reader parse-ebus-paket #:sof? #f #:eof? #f) input-port)])
+    (cond ((not (false? syn))
+           (display (format "drop ~s x SYN (~s) ~n" syn ebus-const-syn))))
     (cond ((not (false? paket))
-           (cond ((not (false? syn))
-                 (display (format "drop ~s x SYN (~s) ~n" syn ebus-const-syn))))
-           (display (format "Paket ~s~n" paket)))
+           paket)
+          ((eof-object? (peek-byte input-port))
+           eof)
           (else
            (display (format "drop ~s ~n" (peek-byte input-port)))
-           (file-position input-port (+ 1 (file-position input-port)))
-           ))
-    (cond ((not (eof-object? (peek-byte input-port)))
-           (read-ebus)))))
+           ; skip one byte
+           (read-byte input-port)
+           ;(file-position input-port (+ 1 (file-position input-port)))
+           (read-ebus input-port)))))
+    
+(define (main input-port)
+  (let ([paket (read-ebus input-port)])
+    (display (format "Paket ~s~n" paket))
+    (cond ((not (eof-object? paket)) (main input-port)))))
+
+;(define input-port (open-input-file "../doc/dumps/dump_2011-12-17_23-04-00.bin"))       
+(main (current-input-port))
+
+;((make-reader ebus-payload #:sof? #f #:eof? #f) (open-input-bytes (bytes 169 1 3  96)))
 
-(read-ebus)
 
 
 ;(define-values (cin cout)
-- 
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