racket: aufgraeumt, data2c gefixt

1 files changed, 166 insertions, 0 deletions

diff --git a/ebus-racket/ebus/layer7.rkt b/ebus-racket/ebus/layer7.rkt
new file mode 100644
index 0000000..3bcad01
--- /dev/null
+++ b/ebus-racket/ebus/layer7.rkt
@@ -0,0 +1,166 @@
+#lang racket/base
+(require racket/list
+         (planet lizorkin/sxml:2:1/sxml)
+         (planet lizorkin/ssax:2:0/ssax)
+         "layer2.rkt")
+
+(define logger (make-logger 'ebus-layer7 (current-logger)))
+
+(define definition
+  (ssax:xml->sxml (open-input-file "../ebus-xml/ebus.xml")
+                  '[(#f . "http://xapek.org/ebus/0.1")]))
+
+(define (paket ebus-paket)
+  (define primaryCommand (layer2-ebus-paket-primaryCommand ebus-paket))
+  (define secondaryCommand (layer2-ebus-paket-secondaryCommand ebus-paket))
+  ((sxpath (string-append "//packet[@primary=" (number->string primaryCommand)
+			  " and @secondary=" (number->string secondaryCommand) "]"))
+   definition))
+
+;; returns the full device-definition
+(define (device address)
+  ((sxpath (string-append "//devices/device[@address=" (number->string address) "]"))
+   definition))
+
+;; returns device-name in a list or empty-list
+(define (device-name address)
+  (first ((sxpath "@name/text()") (device address))))
+
+
+(define (paket-fields ebus-paket)
+  (define paket-definition (paket ebus-paket))
+  (cond ((> (length paket-definition) 0)
+	 (let* 
+	     ([paket-name (string-append 
+			   (device-name (layer2-ebus-paket-source ebus-paket))
+			   "." 
+			   (first ((sxpath "@name/text()") paket-definition)))]
+	      [fields ((sxpath "fields/*") paket-definition)]
+	      [values 
+	       (for/list ([field fields]) (paket-fields-dispatch-decoder ebus-paket field paket-name))])
+	   ;; filter invalid values
+	   (for/list ([value values] #:when (not (void? value)))
+		     value)))
+	(else (void (log-message logger 'warning (format "Unknown Paket: ~s" ebus-paket) #t)))))
+
+(define (paket-fields-dispatch-decoder ebus-paket field paket-name)
+  (define datatype ((sxpath "name()") field))
+  (define name (string-append paket-name "." (first ((sxpath "@name/text()") field))))
+  (define offset (string->number (first ((sxpath "@offset/text()") field))))
+  (define payload (layer2-ebus-paket-payload ebus-paket))
+  (cond ((string=? "bit" datatype)
+	 (list name datatype offset
+	       (field-decoder-bit (list-ref payload offset))))
+	((string=? "bcd" datatype)
+	 (list name datatype offset
+	       (field-decoder-bcd (list-ref payload offset))))
+	((string=? "data1b" datatype)
+	 (list name datatype offset
+	       (field-decoder-data1b (list-ref payload offset))))
+	((string=? "data1c" datatype)
+	 (list name datatype offset
+	       (field-decoder-data1c (list-ref (layer2-ebus-paket-payload ebus-paket) offset))))
+	((string=? "byte" datatype)
+	 (list name datatype offset (list-ref payload offset)))
+	((string=? "data2b" datatype)
+	 (list name datatype offset
+	       (field-decoder-data2b (list-ref payload offset)
+				     (list-ref payload (+ offset 1)))))
+	((string=? "data2c" datatype)
+	 (list name datatype offset
+	       (field-decoder-data2c (list-ref payload offset)
+				     (list-ref payload (+ offset 1)))))
+	((string=? "word" datatype)
+	 (list name datatype offset
+	       (field-decoder-word (list-ref payload offset)
+				   (list-ref payload (+ offset 1)))))
+	((string=? "byteEnum" datatype)
+	 (list name datatype offset
+	       (field-decoder-byteEnum (list-ref payload offset) field)))
+	(else (void (log-message logger 'error (format "unknown datatype: ~a" datatype) #t)))))
+
+;; type bit
+(define (field-decoder-bit value)
+  (cond ((= value 1) 1)
+        (else 0)))
+
+;; type data1b
+(define (field-decoder-data1b value)
+  value)
+
+;; type data1c
+(define (field-decoder-data1c value)
+  (/ value 2.0))
+
+;; type data2b
+(define (field-decoder-data2b lowByte highByte)
+  (if (= (bitwise-and highByte 128) 128)
+      (* -1 
+	 (+ (+ 256 (bitwise-not highByte))
+	    (/ (+ 256 (bitwise-not (+ lowByte 1))) 256.0)))
+      (+ highByte (/ lowByte 256.0))))
+
+ ;; type data2c
+ ;;    Beispiel für die Berechnung:
+ ;;    if ((x & 8000h) == 8000h) // y negativ
+ ;;    y = - [dez(High_Byte(!x)) 16 + dez(High_Nibble (Low_Byte (!x)))
+ ;;    + (dez(Low_Nibble (Low_Byte (!x))) +1 ) / 16]
+ ;;    else                       // y positiv
+ ;;    y = dez(High_Byte(x)) 16 + dez(High_ Nibble (Low Byte (x)))
+ ;;    + dez(Low_ Nibble (Low Byte (x))) / 16
+(define (field-decoder-data2c lowByte highByte)
+  (define (lowNibble v)
+    (bitwise-and v #x0f))
+  (define (highNibble v)
+    (arithmetic-shift v -4))
+  (define (u-not v)
+    (+ 256 (bitwise-not v)))
+  (if (= (bitwise-and highByte 128) 128)
+      (* -1
+	  (+ (arithmetic-shift (u-not highByte) 4)
+	     (highNibble (u-not lowByte))
+             (/ (+ (lowNibble (u-not lowByte)) 1)
+                16.0)))
+      (+ (arithmetic-shift highByte 4)
+         (highNibble lowByte)
+         (/
+           (lowNibble lowByte)
+           16))))
+
+;; type byteEnum
+(define (field-decoder-byteEnum value field-definition)
+  (define (pred l)
+    (= value (list-ref l 0)))
+  (define all-options (for/list ([option ((sxpath "option") field-definition)])
+				(list (string->number (first ((sxpath "@value/text()") option))) ;; value, name
+				      (first ((sxpath "@name/text()") option)))))
+  (define options (filter pred all-options))
+  (cond ((= (length options) 1)
+	 (list-ref (first options) 1))
+	(else "<undefined>")))
+
+;; type word
+(define (field-decoder-word lowByte highByte)
+  (+ lowByte
+     (arithmetic-shift highByte 8)))
+
+;; type bcd
+(define (field-decoder-bcd value)
+  (+ (bitwise-and value #x0f)
+     (arithmetic-shift value -4)))
+  
+;; read one ebus-paket or eof from input-port
+;; or return #<eof>
+(define (read-ebus input-port)
+  (define paket (layer2-read-ebus input-port))
+  (cond ((layer2-ebus-paket? paket)
+	 (paket-fields paket))
+	(else paket)))
+
+(provide (prefix-out layer7- paket)
+         (prefix-out layer7- paket-fields)
+         (prefix-out layer7- device)
+         (prefix-out layer7- device-name)
+	 ;; read ebus from port an return fields from next paket
+	 (prefix-out layer7- read-ebus)
+	 (prefix-out layer7- logger))