simpleq.h: import unmodified file from BSD coreutils

[skip ci]

src/bsd-coreutils/compat/include/simpleq.h

@@ -0,0 +1,49 @@
+/*
+ * Darwin comes with an outdated version of sys/queue.h
+ * however since Darwin is BSD based we can fix this by
+ * using a fake queue, and redefinging a lot of the structures
+ */
+
+#undef SIMPLEQ_HEAD
+#undef SIMPLEQ_ENTRY
+#undef SIMPLEQ_FOREACH
+#undef SIMPLEQ_INSERT_TAIL
+#undef SIMPLEQ_FIRST
+#undef SIMPLEQ_END
+#undef SIMPLEQ_NEXT
+
+#define SIMPLEQ_FIRST(head) ((head)->sqh_first)
+#define SIMPLEQ_EMPTY(head) (SIMPLEQ_FIRST (head) == SIMPLEQ_END (head))
+#define SIMPLEQ_END(head) NULL
+#define SIMPLEQ_NEXT(elm, field) ((elm)->field.sqe_next)
+
+#define SIMPLEQ_HEAD(name, type)                                              \
+  struct name                                                                 \
+  {                                                                           \
+    struct type *sqh_first; /* first element */                               \
+    struct type **sqh_last; /* addr of last next element */                   \
+  }
+
+#define SIMPLEQ_ENTRY(type)                                                   \
+  struct                                                                      \
+  {                                                                           \
+    struct type *sqe_next; /* next element */                                 \
+  }
+
+#define SIMPLEQ_INSERT_TAIL(head, elm, field)                                 \
+  do                                                                          \
+    {                                                                         \
+      (elm)->field.sqe_next = NULL;                                           \
+      *(head)->sqh_last = (elm);                                              \
+      (head)->sqh_last = &(elm)->field.sqe_next;                              \
+    }                                                                         \
+  while (0)
+
+#define SIMPLEQ_HEAD_INITIALIZER(head)                                        \
+  {                                                                           \
+    NULL, &(head).sqh_first                                                   \
+  }
+
+#define SIMPLEQ_FOREACH(var, head, field)                                     \
+  for ((var) = SIMPLEQ_FIRST (head); (var) != SIMPLEQ_END (head);             \
+       (var) = SIMPLEQ_NEXT (var, field))