rewrite bytevector-copy in c

piclib/prelude.scm

@@ -668,31 +668,6 @@
 	   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)))
-         (vs #f))
-    (if (eq? from to)
-        (begin
-          (set! vs (make-bytevector (- end start)))
-          (bytevector-copy! vs 0 from start end)
-          (bytevector-copy! to at vs))
-        (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 (- end start))))
-      (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)))))
@@ -726,8 +701,8 @@
     (list->bytevector (map char->integer (string->list s start end)))))
 
 (export bytevector
-        bytevector-copy!
+        bytevector->list
-        bytevector-copy
+        list->bytevector
         bytevector-append
         utf8->string
         string->utf8)

src/blob.c

@@ -100,6 +100,60 @@ pic_blob_bytevector_u8_set(pic_state *pic)
   return pic_none_value();
 }
 
+static pic_value
+pic_blob_bytevector_copy_i(pic_state *pic)
+{
+  pic_blob *to, *from;
+  int n, at, start, end;
+
+  n = pic_get_args(pic, "bib|ii", &to, &at, &from, &start, &end);
+
+  switch (n) {
+  case 3:
+    start = 0;
+  case 4:
+    end = from->len;
+  }
+
+  if (to == from && (start <= at && at < end)) {
+    /* copy in reversed order */
+    at += end - start;
+    while (start < end) {
+      to->data[--at] = from->data[--end];
+    }
+    return pic_none_value();
+  }
+
+  while (start < end) {
+    to->data[at++] = from->data[start++];
+  }
+
+  return pic_none_value();
+}
+
+static pic_value
+pic_blob_bytevector_copy(pic_state *pic)
+{
+  pic_blob *from, *to;
+  int n, start, end, i = 0;
+
+  n = pic_get_args(pic, "b|ii", &from, &start, &end);
+
+  switch (n) {
+  case 1:
+    start = 0;
+  case 2:
+    end = from->len;
+  }
+
+  to = pic_blob_new(pic, end - start);
+  while (start < end) {
+    to->data[i++] = from->data[start++];
+  }
+
+  return pic_obj_value(to);
+}
+
 void
 pic_init_blob(pic_state *pic)
 {
@@ -108,4 +162,6 @@ pic_init_blob(pic_state *pic)
   pic_defun(pic, "bytevector-length", pic_blob_bytevector_length);
   pic_defun(pic, "bytevector-u8-ref", pic_blob_bytevector_u8_ref);
   pic_defun(pic, "bytevector-u8-set!", pic_blob_bytevector_u8_set);
+  pic_defun(pic, "bytevector-copy!", pic_blob_bytevector_copy_i);
+  pic_defun(pic, "bytevector-copy", pic_blob_bytevector_copy);
 }