feat(utils): Add datatype bundle object array

utils/BUILD

@@ -37,3 +37,12 @@ cc_library(
         "@entangled//common/model:transaction",
     ],
 )
+
+cc_library(
+    name = "bundle_array",
+    srcs = ["bundle_array.h"],
+    deps = [
+        "@com_github_uthash//:uthash",
+        "@entangled//common/model:bundle",
+    ],
+)

utils/bundle_array.h

@@ -0,0 +1,61 @@
+/*
+ * Copyright (C) 2019 BiiLabs Co., Ltd. and Contributors
+ * All Rights Reserved.
+ * This is free software; you can redistribute it and/or modify it under the
+ * terms of the MIT license. A copy of the license can be found in the file
+ * "LICENSE" at the root of this distribution.
+ */
+
+#ifndef UTILS_BUNDLE_ARRAY_H_
+#define UTILS_BUNDLE_ARRAY_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "common/model/bundle.h"
+#include "utarray.h"
+
+/**
+ * @file bundle_array.h
+ * @brief Implementation of bundle array object. This object would be used when we fetch multiple
+ * `bundle_transactions_t` objects. It provides an easier way to save and traverse all the bundles.
+ */
+
+typedef UT_array bundle_array_t;
+
+static UT_icd bundle_array_icd = {sizeof(bundle_transactions_t), 0, 0, 0};
+
+/**
+ * Allocate memory of bundle_array_t
+ */
+static inline void bundle_array_new(bundle_array_t **const bundle_array) {
+  utarray_new(*bundle_array, &bundle_array_icd);
+}
+
+/**
+ * @brief The bundle array iterator.
+ */
+#define BUNDLE_ARRAY_FOREACH(bundles, bdl)                                 \
+  for (bdl = (bundle_transactions_t *)utarray_front(bundles); bdl != NULL; \
+       bdl = (bundle_transactions_t *)utarray_next(bundles, bdl))
+
+/**
+ * Free memory of bundle_array_t
+ */
+static inline void bundle_array_free(bundle_array_t **const bundle_array) {
+  // TODO set dtor and use utarray_free() instead.
+  if (bundle_array && *bundle_array) {
+    bundle_transactions_t *bundle = NULL;
+    iota_transaction_t *tx = NULL;
+    BUNDLE_ARRAY_FOREACH(*bundle_array, bundle) { bundle_transactions_free(&bundle); }
+    free(*bundle_array);
+  }
+  *bundle_array = NULL;
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif  // UTILS_BUNDLE_ARRAY_H_

utils/pow.h

@@ -10,10 +10,10 @@
 #define UTILS_POW_H_
 
 #include <stdint.h>
-#include "./utarray.h"
 #include "accelerator/errors.h"
 #include "common/model/bundle.h"
 #include "common/trinary/flex_trit.h"
+#include "utarray.h"
 
 #ifdef __cplusplus
 extern "C" {