addition: next and peek, need testing

src/arraylist.c

@@ -506,3 +506,50 @@ ArrayListErr arrayslice_destroy(ArraySlice **slice) {
 
     return ARRLIST_OK;
 }
+
+bool arrayslice_is_valid(const ArraySlice *slice) {
+    if (slice == NULL) {
+        return false;
+    }
+
+    return slice->current != slice->end;
+}
+
+size_t arrayslice_size(const ArraySlice *slice) {
+    if (slice == NULL) {
+        return 0;
+    }
+
+    return slice->end - slice->start;
+}
+
+ArrayListErr arrayslice_peek(const ArraySlice *slice, void *out) {
+    if (slice == NULL || out == NULL) {
+        return ARRLIST_NULL_ARG;
+    }
+
+    if (slice->current == slice->end) {
+        return ARRLIST_INVALID_SLICE;
+    }
+
+    arraylist_get(slice->arr, slice->current, out);
+
+    return ARRLIST_OK;
+}
+
+ArrayListErr arrayslice_next(ArraySlice *slice, void *out) {
+    // HERE, it makes sense that you want to advance to the next
+    // without actually getting the value so it's good
+    if (slice == NULL) {
+        return ARRLIST_NULL_ARG;
+    }
+
+    if (slice->current == slice->end) {
+        return ARRLIST_INVALID_SLICE;
+    }
+
+    arraylist_get(slice->arr, slice->current, out);
+
+    slice->current++;
+    return ARRLIST_OK;
+}