add missing bytevector functions

README.md

@@ -71,7 +71,7 @@
 | 6.6 Characters | yes | |
 | 6.7 Strings | yes | `substring` is not provided |
 | 6.8 Vectors | yes | |
-| 6.9 Bytevectors | incomplete | TODO: string<->utf8 conversion, etc |
+| 6.9 Bytevectors | incomplete | TODO: string<->utf8 conversion |
 | 6.10  Control features | incomplete | TODO: `string-map`, `vector-map`, ...etc |
 | 6.11 Exceptions | yes | TODO: native error handling |
 | 6.12 Environments and evaluation | N/A | |

piclib/built-in.scm

@@ -519,3 +519,30 @@
 	  ((< i len)
 	   v)
 	(bytevector-u8-set! v i (car l))))))
+
+(define (bytevector-copy! to at from . opts)
+  (let ((start (if (pair? opts) (car opts) 0))
+	(end (if (>= (length opts) 2)
+		 (cadr opts)
+		 (bytevector-length from))))
+    (do ((i at (+ i 1))
+	 (j start (+ j 1)))
+	((< j end))
+      (bytevector-u8-set! to i (bytevector-u8-ref from j)))))
+
+(define (bytevector-copy v . opts)
+  (let ((start (if (pair? opts) (car opts) 0))
+	(end (if (>= (length opts) 2)
+		 (cadr opts)
+		 (bytevector-length v))))
+    (let ((res (make-bytevector (bytevector-length v))))
+      (bytevector-copy! res 0 v start end)
+      res)))
+
+(define (bytevector-append . vs)
+  (define (bytevector-append-2-inv w v)
+    (let ((res (make-bytevector (+ (bytevector-length v) (bytevector-length w)))))
+      (bytevector-copy! res 0 v)
+      (bytevector-copy! res (bytevector-length v) w)
+      res))
+  (fold bytevector-append-2-inv #() vs))