src/arraylist.c

@@ -528,7 +528,7 @@ ArrayListErr arrayslice_peek(const ArraySlice *slice, void *out) {
         return ARRLIST_NULL_ARG;
     }
 
-    if (slice->current == slice->end) {
+    if (slice->current >= slice->end) {
         return ARRLIST_INVALID_SLICE;
     }
 
@@ -569,7 +569,7 @@ ArrayListErr arrayslice_advance(ArraySlice *slice, size_t n) {
         return ARRLIST_NULL_ARG;
     }
 
-    if (n > SIZE_MAX - slice->current || slice->current + n >= slice->end) {
+    if (n > SIZE_MAX - slice->current || slice->current + n > slice->end) {
         return ARRLIST_OUT_OF_BOUNDS;
     }
     

test/test_arraylist.c

@@ -1479,6 +1479,80 @@ static void test_slice_double_destroy(void **state) {
     arraylist_destroy(&arr);
 }
 
+// Slice peek
+static void test_slice_peek_valid_array(void **state) {
+    (void) state;
+
+    ArrayList *arr = arraylist_init(64, sizeof(int));
+    assert_non_null(arr);
+
+    for (int i = 0; i < 10; i++) {
+        assert_uint_equal(arraylist_push_back(arr, &i), ARRLIST_OK);
+    }
+
+    ArraySlice *slice = arraylist_slice(arr, 0, arraylist_size(arr));
+    assert_non_null(slice);
+
+    int m;
+    assert_uint_equal(arrayslice_peek(slice, &m), ARRLIST_OK);
+    assert_int_equal(m, 0);
+
+    arrayslice_destroy(&slice);
+    arraylist_destroy(&arr);
+}
+
+static void test_slice_peek_invalid_array(void **state) {
+    (void) state;
+
+    ArrayList *arr = arraylist_init(64, sizeof(int));
+    assert_non_null(arr);
+
+    for (int i = 0; i < 10; i++) {
+        assert_uint_equal(arraylist_push_back(arr, &i), ARRLIST_OK);
+    }
+
+    ArraySlice *slice = arraylist_slice(arr, 0, arraylist_size(arr));
+    assert_non_null(slice);
+
+    assert_uint_equal(arrayslice_advance(slice, 10), ARRLIST_OK);
+
+    int m;
+    assert_uint_equal(arrayslice_peek(slice, &m), ARRLIST_INVALID_SLICE);
+    assert_int_equal(m, 0);
+
+    arrayslice_destroy(&slice);
+    arraylist_destroy(&arr);
+}
+
+static void test_slice_peek_null_out(void **state) {
+    (void) state;
+
+    ArrayList *arr = arraylist_init(64, sizeof(int));
+    assert_non_null(arr);
+
+    for (int i = 0; i < 10; i++) {
+        assert_uint_equal(arraylist_push_back(arr, &i), ARRLIST_OK);
+    }
+
+    ArraySlice *slice = arraylist_slice(arr, 0, arraylist_size(arr));
+    assert_non_null(slice);
+
+    assert_uint_equal(arrayslice_peek(slice, NULL), ARRLIST_NULL_ARG);
+
+    arrayslice_destroy(&slice);
+    arraylist_destroy(&arr);
+}
+
+static void test_slice_peek_null_slice(void **state) {
+    (void) state;
+
+    ArraySlice *slice = NULL;
+
+    int m;
+    assert_uint_equal(arrayslice_peek(slice, &m), ARRLIST_NULL_ARG);
+    assert_int_equal(m, 0);
+}
+
 int main(void) {
     const struct CMUnitTest init[] = {
         cmocka_unit_test(test_init_valid_parameters),
@@ -1626,6 +1700,13 @@ int main(void) {
         cmocka_unit_test(test_slice_double_destroy),
     };
 
+    const struct CMUnitTest slice_peek[] = {
+        cmocka_unit_test(test_slice_peek_valid_array),
+        cmocka_unit_test(test_slice_peek_invalid_array),
+        cmocka_unit_test(test_slice_peek_null_slice),
+        cmocka_unit_test(test_slice_peek_null_out),
+    };
+    
     int rc = 0;
 
     rc += cmocka_run_group_tests(init, NULL, NULL);
@@ -1646,6 +1727,7 @@ int main(void) {
     rc += cmocka_run_group_tests(slice_array, NULL, NULL);
     rc += cmocka_run_group_tests(slice_array_unsafe, NULL, NULL);
     rc += cmocka_run_group_tests(slice_destroy, NULL, NULL);
+    rc += cmocka_run_group_tests(slice_peek, NULL, NULL);
 
     return rc;
 }