rewrite vector-copy in c

piclib/prelude.scm

@@ -700,31 +700,6 @@
 (define (vector . objs)
   (list->vector objs))
 
-(define (vector-copy! to at from . opts)
-  (let* ((start (if (pair? opts) (car opts) 0))
-         (end (if (>= (length opts) 2)
-                  (cadr opts)
-                  (vector-length from)))
-         (vs #f))
-    (if (eq? from to)
-        (begin
-          (set! vs (make-vector (- end start)))
-          (vector-copy! vs 0 from start end)
-          (vector-copy! to at vs))
-        (do ((i at (+ i 1))
-             (j start (+ j 1)))
-            ((= j end))
-          (vector-set! to i (vector-ref from j))))))
-
-(define (vector-copy v . opts)
-  (let ((start (if (pair? opts) (car opts) 0))
-	(end (if (>= (length opts) 2)
-		 (cadr opts)
-		 (vector-length v))))
-    (let ((res (make-vector (- end start))))
-      (vector-copy! res 0 v start end)
-      res)))
-
 (define (vector-append . vs)
   (define (vector-append-2-inv w v)
     (let ((res (make-vector (+ (vector-length v) (vector-length w)))))

src/vector.c

@@ -119,6 +119,60 @@ pic_vec_vector_set(pic_state *pic)
   return pic_none_value();
 }
 
+static pic_value
+pic_vec_vector_copy_i(pic_state *pic)
+{
+  pic_vec *to, *from;
+  int n, at, start, end;
+
+  n = pic_get_args(pic, "viv|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_vec_vector_copy(pic_state *pic)
+{
+  pic_vec *vec, *to;
+  int n, start, end, i = 0;
+
+  n = pic_get_args(pic, "v|ii", &vec, &start, &end);
+
+  switch (n) {
+  case 1:
+    start = 0;
+  case 2:
+    end = vec->len;
+  }
+
+  to = pic_vec_new(pic, end - start);
+  while (start < end) {
+    to->data[i++] = vec->data[start++];
+  }
+
+  return pic_obj_value(to);
+}
+
 static pic_value
 pic_vec_list_to_vector(pic_state *pic)
 {
@@ -169,6 +223,8 @@ pic_init_vector(pic_state *pic)
   pic_defun(pic, "vector-length", pic_vec_vector_length);
   pic_defun(pic, "vector-ref", pic_vec_vector_ref);
   pic_defun(pic, "vector-set!", pic_vec_vector_set);
+  pic_defun(pic, "vector-copy!", pic_vec_vector_copy_i);
+  pic_defun(pic, "vector-copy", pic_vec_vector_copy);
   pic_defun(pic, "list->vector", pic_vec_list_to_vector);
   pic_defun(pic, "vector->list", pic_vec_vector_to_list);
 }