You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
172 lines
6.5 KiB
Racket
172 lines
6.5 KiB
Racket
7 years ago
|
#lang sugar/debug racket/base
|
||
|
(require sugar/debug)
|
||
|
(require (for-syntax racket/base br/syntax))
|
||
|
(require racket/match racket/function racket/port br/define sugar/list racket/list)
|
||
|
(provide define-rule :atomic :seq :repeat string/utf-8? string/latin-1? string/ascii? bitfield?)
|
||
|
|
||
|
(define string/utf-8? #t)
|
||
|
(define string/latin-1? 'string/latin-1?)
|
||
|
(define string/ascii? 'string/ascii?)
|
||
|
(define bitfield? 'bitfield?)
|
||
|
|
||
|
(struct binary-problem (msg val) #:transparent)
|
||
|
|
||
|
(define bitfield #f)
|
||
|
(define (read-bits-exact count p)
|
||
|
(define bitcount (inexact->exact (* 10 count)))
|
||
|
(unless (pair? bitfield)
|
||
|
(set! bitfield (bytes->bitfield (read-bytes 1 p))))
|
||
|
(define-values (bits rest) (split-at bitfield bitcount))
|
||
|
(set! bitfield rest)
|
||
|
bits)
|
||
|
|
||
|
(define (read-bytes-exact count p)
|
||
|
(cond
|
||
|
[(integer? count)
|
||
|
(define bs (read-bytes count p))
|
||
|
(unless (and (bytes? bs) (= (bytes-length bs) count))
|
||
|
(raise (binary-problem (format "byte string length ~a" count) bs)))
|
||
|
bs]
|
||
|
[else (read-bits-exact count p)]))
|
||
|
|
||
|
(define (bytes->integer len x)
|
||
|
(when (< (bytes-length x) len) (raise-argument-error 'bytes->integer "too short" x))
|
||
|
(cond
|
||
|
[(= len 1) (bytes-ref x 0)]
|
||
|
[else (integer-bytes->integer x #f #f)]))
|
||
|
|
||
|
(define (integer->bytes len x)
|
||
|
(case len
|
||
|
[(1) (bytes x)]
|
||
|
[(2 4 8) (integer->integer-bytes x len #f #f)]
|
||
|
[else (raise-argument-error 'integer->bytes "byte length 1 2 4 8" len)]))
|
||
|
|
||
|
(define (bytes->ascii bs)
|
||
|
(list->string (for/list ([b (in-bytes bs)])
|
||
|
(if (< b 128)
|
||
|
(integer->char b)
|
||
|
(raise (binary-problem "ascii byte < 128" b))))))
|
||
|
|
||
|
(define (ascii->bytes str)
|
||
|
(apply bytes (for/list ([c (in-string str)])
|
||
|
(char->integer c))))
|
||
|
|
||
|
(define (bytes->bitfield bs)
|
||
|
(for*/list ([b (in-bytes bs)]
|
||
|
[idx (in-range 8)])
|
||
|
(bitwise-bit-set? b idx)))
|
||
|
|
||
|
(define (bitfield->bytes bf)
|
||
|
(unless (zero? (modulo (length bf) 8))
|
||
|
(raise-argument-error 'bitfield->bytes "bitfield length a multiple of 8" (length bf)))
|
||
|
(apply bytes
|
||
|
(let loop ([bf bf][acc null])
|
||
|
(if (null? bf)
|
||
|
(reverse acc)
|
||
|
(let-values ([(bits rest) (split-at bf 8)])
|
||
|
(loop rest (cons (for/sum ([b (in-list bits)]
|
||
|
[pow (in-range 8)]
|
||
|
#:when b)
|
||
|
(expt 2 pow)) acc)))))))
|
||
|
|
||
|
(module+ test
|
||
|
(check-equal? (bitfield->bytes (bytes->bitfield #"AB")) #"AB"))
|
||
|
|
||
|
|
||
|
(define (:atomic count #:type [type #f])
|
||
|
(procedure-rename
|
||
|
(λ (x)
|
||
|
(define-values (input-proc output-proc)
|
||
|
(cond
|
||
|
[(equal? type integer?) (values (curry bytes->integer count)
|
||
|
(curry integer->bytes count))]
|
||
|
[(equal? type string/ascii?) (values bytes->ascii ascii->bytes)]
|
||
|
[(equal? type bitfield?) (values bytes->bitfield bitfield->bytes)]
|
||
|
[else (values identity identity)]))
|
||
|
|
||
|
(if (input-port? x)
|
||
|
(input-proc (read-bytes-exact count x))
|
||
|
(let ([result (output-proc x)])
|
||
|
(unless (and (bytes? result) (= (bytes-length result) count))
|
||
|
(raise (binary-problem (format "byte string length ~a" count) result)))
|
||
|
result))) (gensym 'atomic-)))
|
||
|
|
||
|
(define (list->hash-with-keys keys vals)
|
||
|
(make-hash (map cons keys vals)))
|
||
|
|
||
|
(define (hash->list-with-keys keys h)
|
||
|
(for/list ([k (in-list keys)])
|
||
|
(hash-ref h k)))
|
||
|
|
||
|
(define (procedure-name proc)
|
||
|
(string->symbol (cadr (regexp-match #rx"^#<procedure:(.*?)>$" (with-output-to-string (λ () (display proc)))))))
|
||
|
|
||
|
(define (hash-has-keys? h keys)
|
||
|
(define (sortation xs) (sort xs #:key symbol->string string<?))
|
||
|
(equal? (sortation (hash-keys h)) (sortation keys)))
|
||
|
|
||
|
|
||
|
(define (resolve-duplicates xs)
|
||
|
(if (members-unique? xs)
|
||
|
xs
|
||
|
(for/list ([x (in-list xs)]
|
||
|
[idx (in-naturals 1)])
|
||
|
(string->symbol (format "~a-~a" x idx)))))
|
||
|
|
||
|
(define (:seq #:type [type #f] . rule-procs)
|
||
|
(procedure-rename
|
||
|
(λ (x) (define-values (input-proc output-proc output-check)
|
||
|
(cond
|
||
|
[(equal? type hash?)
|
||
|
(define rule-proc-names (resolve-duplicates (map procedure-name rule-procs)))
|
||
|
(values (curry list->hash-with-keys rule-proc-names)
|
||
|
(curry hash->list-with-keys rule-proc-names)
|
||
|
(λ (x)
|
||
|
(unless (and (hash? x) (hash-has-keys? x rule-proc-names))
|
||
|
(raise (binary-problem (format "hash with ~a keys, namely ~a" (length rule-procs) rule-proc-names) x)))))]
|
||
|
[else (values identity identity
|
||
|
(λ (x)
|
||
|
(unless (and (list? x) (= (length rule-procs) (length x)))
|
||
|
(raise (binary-problem (format "list of ~a values" (length rule-procs)) x)))))]))
|
||
|
(match x
|
||
|
[(? input-port? p) (input-proc (map (λ (rule-proc) (rule-proc p)) rule-procs))]
|
||
|
[else
|
||
|
(output-check x)
|
||
|
(apply bytes-append (map (λ (rp xi) (rp xi)) rule-procs (output-proc x)))])) (gensym 'seq)))
|
||
|
|
||
|
|
||
|
(define (:repeat count . rule-procs)
|
||
|
(λ (p) (append-map (λ (i) (map (λ (r-p) (r-p p) rule-procs))) (range count))))
|
||
|
|
||
|
(define-macro (define-rule ID RULE-PROC)
|
||
|
#'(define (ID [x (current-input-port)])
|
||
|
(with-handlers ([binary-problem? (λ (exn)
|
||
|
(raise-result-error
|
||
|
'ID
|
||
|
(binary-problem-msg exn)
|
||
|
(binary-problem-val exn)))])
|
||
|
(RULE-PROC x))))
|
||
|
|
||
|
|
||
|
(module+ test
|
||
|
(require rackunit)
|
||
|
|
||
|
(define-rule foo (:seq bar zam #:type hash?))
|
||
|
(define-rule bar (:atomic 1 #:type integer?))
|
||
|
(define-rule zam (:atomic 2 #:type integer?))
|
||
|
|
||
|
(check-equal? #"AB" (zam (zam (open-input-bytes #"AB"))) (zam 16961))
|
||
|
(check-equal? #"123" (foo (foo (open-input-bytes #"123"))) (foo '#hash((bar . 49) (zam . 13106))))
|
||
|
|
||
|
|
||
|
(define-rule foolist (:seq bar zam bar zam))
|
||
|
(check-equal? #"123456" (foolist (foolist (open-input-bytes #"123456"))) (foolist '(49 13106 52 13877)))
|
||
|
|
||
|
(define-rule hashrule (:seq bar zam bar zam bar #:type hash?))
|
||
|
(check-equal? #"1234567" (hashrule (hashrule (open-input-bytes #"1234567")))
|
||
|
(hashrule '#hash((zam-4 . 13877) (bar-3 . 52) (zam-2 . 13106) (bar-1 . 49) (bar-5 . 55))))
|
||
|
|
||
|
|
||
|
(define-rule flag (:atomic .4))
|
||
|
(check-equal? (flag (open-input-bytes #"A")) '(#t #f #f #f))
|
||
|
)
|