X-Git-Url: https://git.jsancho.org/?p=guile-assimp.git;a=blobdiff_plain;f=src%2Flow-level.scm;h=53bb39eb4d83906996191061a09dc729fc9f573d;hp=a184082929ae37f43c003f5e384141e6e5ee86c1;hb=cc3b67814bd3d1d26e1d1d5523db7bf19384bf33;hpb=ebdf468033662662f62674baf9bfa915e6f6a262

diff --git a/src/low-level.scm b/src/low-level.scm
index a184082..53bb39e 100644
--- a/src/low-level.scm
+++ b/src/low-level.scm
@@ -16,9 +16,13 @@
 
 
 (define-module (assimp low-level)
+  #:use-module (ice-9 iconv)
+  #:use-module (rnrs bytevectors)
   #:use-module (system foreign))
 
 
+;;; Parsers Definition
+
 (define-syntax define-struct-parser
   (lambda (x)
     (syntax-case x ()
@@ -30,4 +34,122 @@
 		  '(field-name ...)
 		  (parse-c-struct pointer (list field-type ...)))))))))
 
-(export define-struct-parser)
+(export-syntax define-struct-parser)
+
+
+;;; Type Generation
+
+(define-syntax define-conversion-type
+  (lambda (x)
+    (define (mk-string . args)
+      (string-concatenate
+       (map (lambda (a)
+	      (if (string? a)
+		  a
+		  (symbol->string (syntax->datum a))))
+	    args)))
+    (define (mk-symbol . args)
+      (datum->syntax x
+        (string->symbol
+	 (apply mk-string args))))
+    (syntax-case x (->)
+      ((_ parser -> name (field-name field-proc) ...)
+       (with-syntax ((type? (mk-symbol #'name "?"))
+		     (wrap-type (mk-symbol "wrap-" #'name))
+		     (unwrap-type (mk-symbol "unwrap-" #'name))
+		     (output-string (mk-string "#<" #'name " ~x>"))
+		     (type-contents (mk-symbol #'name "-contents"))
+		     (type-parse (mk-symbol #'name "-parse"))
+		     ((field-reader ...) (map (lambda (f) (mk-symbol #'name "-" (car f))) #'((field-name field-proc) ...))))
+         #'(begin
+	     (define-wrapped-pointer-type name
+	       type?
+	       wrap-type unwrap-type
+	       (lambda (x p)
+		 (format p output-string
+			 (pointer-address (unwrap-type x)))))
+	     (define (type-parse wrapped)
+	       (let ((unwrapped (unwrap-type wrapped)))
+		 (cond ((= (pointer-address unwrapped) 0)
+			'())
+		       (else
+			(parser unwrapped)))))
+	     (define-type-contents type-contents type-parse (field-name field-proc) ...)
+	     (define-field-reader field-reader type-parse field-proc)
+	     ...
+	     ))))))
+
+(define-macro (define-type-contents type-contents type-parse . fields)
+  `(define (,type-contents wrapped)
+     (let ((alist (,type-parse wrapped)))
+       (list ,@(map (lambda (f)
+		      `(cons ',(car f) ,(cadr f)))
+		    fields)))))
+
+(define-macro (define-field-reader field-reader type-parse body)
+  `(define (,field-reader wrapped)
+     (let ((alist (,type-parse wrapped)))
+       ,body)))
+
+(define-macro (field name)
+  `(assoc-ref alist ,name))
+
+(export-syntax define-conversion-type
+	       field)
+
+
+;;; Support functions for type generation
+
+(define (bv-uint-ref pointer index)
+  (bytevector-uint-ref
+   (pointer->bytevector pointer 4 index)
+   0
+   (native-endianness)
+   4))
+
+(define* (array size root #:key (element-size 4) (element-proc bv-uint-ref))
+  (cond ((= (pointer-address root) 0)
+	 '())
+	(else
+	 (let loop ((i 0))
+	   (cond ((= i size)
+		  '())
+		 (else
+		  (cons (element-proc root (* element-size i))
+			(loop (+ i 1)))))))))
+
+(define (get-element-address root-pointer offset)
+  (make-pointer (+ (pointer-address root-pointer) offset)))
+
+(define (sized-string s)
+  (cond (s
+	 (bytevector->string
+	  (u8-list->bytevector (list-head (cadr s) (car s)))
+	  (fluid-ref %default-port-encoding)))
+	(else
+	 #f)))
+
+(define (wrap pointers wrap-proc)
+  (define (make-wrap element)
+    (let ((pointer
+	   (cond ((pointer? element)
+		  (if (= (pointer-address element) 0)
+		      #f
+		      element))
+		 ((= element 0)
+		  #f)
+		 (else
+		  (make-pointer element)))))
+      (cond (pointer
+	     (wrap-proc pointer))
+	    (else
+	     #f))))
+  (cond ((list? pointers)
+	 (map make-wrap pointers))
+	(else
+	 (make-wrap pointers))))
+
+(export array
+	get-element-address
+	sized-string
+	wrap)