diff options
Diffstat (limited to 'ebus-racket/layer7.rkt')
| -rw-r--r-- | ebus-racket/layer7.rkt | 60 |
1 files changed, 53 insertions, 7 deletions
diff --git a/ebus-racket/layer7.rkt b/ebus-racket/layer7.rkt index 5b8f496..8f8f39e 100644 --- a/ebus-racket/layer7.rkt +++ b/ebus-racket/layer7.rkt @@ -1,16 +1,19 @@ #lang racket -(require (planet lizorkin/sxml:2:1/sxml)) -(require (planet lizorkin/ssax:2:0/ssax)) +(require (planet lizorkin/sxml:2:1/sxml) + (planet lizorkin/ssax:2:0/ssax) + "layer2.rkt") (define definition (ssax:xml->sxml (open-input-file "../ebus-xml/ebus.xml") '[(#f . "http://xapek.org/ebus/0.1")])) -(define (ebus-paket primaryCommand secondaryCommand) - ((sxpath (string-append "//packet[@primary=" (number->string primaryCommand) - " and @secondary=" (number->string secondaryCommand) "]")) - definition)) +(define (paket ebus-paket) + (let ([primaryCommand (layer2-ebus-paket-primaryCommand ebus-paket)] + [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) @@ -21,6 +24,49 @@ (define (device-name address) ((sxpath "@name/text()") (device address))) -(provide (prefix-out layer7- ebus-paket) + +(define (paket-fields ebus-paket) + (let* ([paket-definition (paket ebus-paket)] + [paket-name (first ((sxpath "@name/text()") paket-definition))] + [fields ((sxpath "fields/*") paket-definition)] + [values (for/list ([field fields]) + (let ([datatype ((sxpath "name()") field)] + [name (string-append paket-name "." (first ((sxpath "@name/text()") field)))] + [offset (string->number (first ((sxpath "@offset/text()") field)))]) + (cond ((string=? "bit" datatype) + (list name datatype offset + (field-decoder-bit (list-ref (layer2-ebus-paket-payload ebus-paket) offset)))) + ((string=? "data1b" datatype) + (list name datatype offset + (field-decoder-data1b (list-ref (layer2-ebus-paket-payload ebus-paket) offset)))) + ((string=? "data2b" datatype) + (list name datatype offset + (field-decoder-data2b (list-ref (layer2-ebus-paket-payload ebus-paket) offset) + (list-ref (layer2-ebus-paket-payload ebus-paket) (+ offset 1))))) + (else (display (string-append "unknown datatype: " datatype)) + (void))) + ))]) + ; filter invalid values + (for/list ([value values] #:when (not (void? value))) + value))) + +;; type bit +(define (field-decoder-bit value) + (cond ((= value 1) 1) + (else 0))) + +;; type data1b +(define (field-decoder-data1b value) + value) + +;; type data2b +(define (field-decoder-data2b lowByte highByte) + (cond ((= (bitwise-and highByte 128) 128) + (* -1 (+ (+ 256 (bitwise-not highByte)) + (/ (+ 256 (bitwise-not (+ lowByte 1))) 256.0)))) + (else (+ highByte (/ lowByte 256.0))))) + +(provide (prefix-out layer7- paket) + (prefix-out layer7- paket-fields) (prefix-out layer7- device) (prefix-out layer7- device-name))
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