Add ARRAY convenience macros

Because dynamically allocated arrays in C are a pain.

liberty.c

@@ -301,6 +301,23 @@ xstrndup (const char *s, size_t n)
 	return copy;
 }
 
+// --- Simple array support ----------------------------------------------------
+
+// The most basic helper macros to make working with arrays not suck
+
+#define ARRAY(type, name) type *name; size_t name ## _len, name ## _size;
+#define ARRAY_INIT_SIZED(a, n)                                                 \
+	BLOCK_START                                                                \
+		(a) = xcalloc (sizeof *(a), (a ## _size) = (n));                       \
+		(a ## _len) = 0;                                                       \
+	BLOCK_END
+#define ARRAY_INIT(a) ARRAY_INIT_SIZED (a, 16)
+#define ARRAY_RESERVE(a, n)                                                    \
+	BLOCK_START                                                                \
+		while ((a ## _size) - (a ## _len) < n)                                 \
+			(a) = xreallocarray ((a), sizeof *(a), (a ## _size) <<= 1);        \
+	BLOCK_END
+
 // --- Double-linked list helpers ----------------------------------------------
 
 #define LIST_HEADER(type)                                                      \