1 files changed, 121 insertions, 0 deletions
diff --git a/contrib/libdiff/include/arraylist.h b/contrib/libdiff/include/arraylist.h
new file mode 100644
index 000000000000..453b71cedd7f
--- /dev/null
+++ b/contrib/libdiff/include/arraylist.h
@@ -0,0 +1,121 @@
+/* Auto-reallocating array for arbitrary member types. */
+/*
+ * Copyright (c) 2020 Neels Hofmeyr <neels@hofmeyr.de>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+/* Usage:
+ *
+ * ARRAYLIST(any_type_t) list;
+ * // OR
+ * typedef ARRAYLIST(any_type_t) any_type_list_t;
+ * any_type_list_t list;
+ *
+ * // pass the number of (at first unused) members to add on each realloc:
+ * ARRAYLIST_INIT(list, 128);
+ * any_type_t *x;
+ * while (bar) {
+ *         // This enlarges the allocated array as needed;
+ *         // list.head may change due to realloc:
+ *         ARRAYLIST_ADD(x, list);
+ *         if (!x)
+ *                 return ENOMEM; 
+ *         *x = random_foo_value;
+ * }
+ * for (i = 0; i < list.len; i++)
+ *         printf("%s", foo_to_str(list.head[i]));
+ * ARRAYLIST_FREE(list);
+ */
+#define ARRAYLIST(MEMBER_TYPE) \
+	struct { \
+		MEMBER_TYPE *head; \
+		MEMBER_TYPE *p; \
+		unsigned int len; \
+		unsigned int allocated; \
+		unsigned int alloc_blocksize; \
+	}
+
+#define ARRAYLIST_INIT(ARRAY_LIST, ALLOC_BLOCKSIZE) do { \
+		(ARRAY_LIST).head = NULL; \
+		(ARRAY_LIST).len = 0; \
+		(ARRAY_LIST).allocated = 0; \
+		(ARRAY_LIST).alloc_blocksize = ALLOC_BLOCKSIZE; \
+	} while(0)
+
+#define ARRAYLIST_ADD(NEW_ITEM_P, ARRAY_LIST) do { \
+		if ((ARRAY_LIST).len && !(ARRAY_LIST).allocated) { \
+			NEW_ITEM_P = NULL; \
+			break; \
+		} \
+		if ((ARRAY_LIST).head == NULL \
+		    || (ARRAY_LIST).allocated < (ARRAY_LIST).len + 1) { \
+			(ARRAY_LIST).p = recallocarray((ARRAY_LIST).head, \
+				(ARRAY_LIST).len, \
+				(ARRAY_LIST).allocated + \
+				((ARRAY_LIST).allocated ? \
+				(ARRAY_LIST).allocated / 2 : \
+				(ARRAY_LIST).alloc_blocksize ? \
+				(ARRAY_LIST).alloc_blocksize : 8), \
+				sizeof(*(ARRAY_LIST).head)); \
+			if ((ARRAY_LIST).p == NULL) { \
+				NEW_ITEM_P = NULL; \
+				break; \
+			} \
+			(ARRAY_LIST).allocated += \
+				(ARRAY_LIST).allocated ? \
+				(ARRAY_LIST).allocated / 2 : \
+				(ARRAY_LIST).alloc_blocksize ? \
+				(ARRAY_LIST).alloc_blocksize : 8, \
+			(ARRAY_LIST).head = (ARRAY_LIST).p; \
+			(ARRAY_LIST).p = NULL; \
+		}; \
+		if ((ARRAY_LIST).head == NULL \
+		    || (ARRAY_LIST).allocated < (ARRAY_LIST).len + 1) { \
+			NEW_ITEM_P = NULL; \
+			break; \
+		} \
+		(NEW_ITEM_P) = &(ARRAY_LIST).head[(ARRAY_LIST).len]; \
+		(ARRAY_LIST).len++; \
+	} while (0)
+
+#define ARRAYLIST_INSERT(NEW_ITEM_P, ARRAY_LIST, AT_IDX) do { \
+		int _at_idx = (AT_IDX); \
+		ARRAYLIST_ADD(NEW_ITEM_P, ARRAY_LIST); \
+		if ((NEW_ITEM_P) \
+		    && _at_idx >= 0 \
+		    && _at_idx < (ARRAY_LIST).len) { \
+			memmove(&(ARRAY_LIST).head[_at_idx + 1], \
+				&(ARRAY_LIST).head[_at_idx], \
+				((ARRAY_LIST).len - 1 - _at_idx) \
+					* sizeof(*(ARRAY_LIST).head)); \
+			(NEW_ITEM_P) = &(ARRAY_LIST).head[_at_idx]; \
+		}; \
+	} while (0)
+
+#define ARRAYLIST_CLEAR(ARRAY_LIST) \
+	(ARRAY_LIST).len = 0
+
+#define ARRAYLIST_FREE(ARRAY_LIST) \
+	do { \
+		if ((ARRAY_LIST).head && (ARRAY_LIST).allocated) \
+			free((ARRAY_LIST).head); \
+		ARRAYLIST_INIT(ARRAY_LIST, (ARRAY_LIST).alloc_blocksize); \
+	} while(0)
+
+#define ARRAYLIST_FOREACH(ITEM_P, ARRAY_LIST) \
+	for ((ITEM_P) = (ARRAY_LIST).head; \
+	     (ITEM_P) - (ARRAY_LIST).head < (ARRAY_LIST).len; \
+	     (ITEM_P)++)
+
+#define ARRAYLIST_IDX(ITEM_P, ARRAY_LIST) ((ITEM_P) - (ARRAY_LIST).head)