Added TCMalloc and JEMalloc projects

BeefRT/JEMalloc/include/jemalloc/internal/qr.h

@@ -0,0 +1,140 @@
+#ifndef JEMALLOC_INTERNAL_QR_H
+#define JEMALLOC_INTERNAL_QR_H
+
+/*
+ * A ring implementation based on an embedded circular doubly-linked list.
+ *
+ * You define your struct like so:
+ *
+ * typedef struct my_s my_t;
+ * struct my_s {
+ *   int data;
+ *   qr(my_t) my_link;
+ * };
+ *
+ * And then pass a my_t * into macros for a_qr arguments, and the token
+ * "my_link" into a_field fields.
+ */
+
+/* Ring definitions. */
+#define qr(a_type)							\
+struct {								\
+	a_type	*qre_next;						\
+	a_type	*qre_prev;						\
+}
+
+/*
+ * Initialize a qr link.  Every link must be initialized before being used, even
+ * if that initialization is going to be immediately overwritten (say, by being
+ * passed into an insertion macro).
+ */
+#define qr_new(a_qr, a_field) do {					\
+	(a_qr)->a_field.qre_next = (a_qr);				\
+	(a_qr)->a_field.qre_prev = (a_qr);				\
+} while (0)
+
+/*
+ * Go forwards or backwards in the ring.  Note that (the ring being circular), this
+ * always succeeds -- you just keep looping around and around the ring if you
+ * chase pointers without end.
+ */
+#define qr_next(a_qr, a_field) ((a_qr)->a_field.qre_next)
+#define qr_prev(a_qr, a_field) ((a_qr)->a_field.qre_prev)
+
+/*
+ * Given two rings:
+ *    a -> a_1 -> ... -> a_n --
+ *    ^                       |
+ *    |------------------------
+ *
+ *    b -> b_1 -> ... -> b_n --
+ *    ^                       |
+ *    |------------------------
+ *
+ * Results in the ring:
+ *   a -> a_1 -> ... -> a_n -> b -> b_1 -> ... -> b_n --
+ *   ^                                                 |
+ *   |-------------------------------------------------|
+ *
+ * a_qr_a can directly be a qr_next() macro, but a_qr_b cannot.
+ */
+#define qr_meld(a_qr_a, a_qr_b, a_field) do {				\
+	(a_qr_b)->a_field.qre_prev->a_field.qre_next =			\
+	    (a_qr_a)->a_field.qre_prev;					\
+	(a_qr_a)->a_field.qre_prev = (a_qr_b)->a_field.qre_prev;	\
+	(a_qr_b)->a_field.qre_prev =					\
+	    (a_qr_b)->a_field.qre_prev->a_field.qre_next;		\
+	(a_qr_a)->a_field.qre_prev->a_field.qre_next = (a_qr_a);	\
+	(a_qr_b)->a_field.qre_prev->a_field.qre_next = (a_qr_b);	\
+} while (0)
+
+/*
+ * Logically, this is just a meld.  The intent, though, is that a_qrelm is a
+ * single-element ring, so that "before" has a more obvious interpretation than
+ * meld.
+ */
+#define qr_before_insert(a_qrelm, a_qr, a_field)			\
+	qr_meld((a_qrelm), (a_qr), a_field)
+
+/* Ditto, but inserting after rather than before. */
+#define qr_after_insert(a_qrelm, a_qr, a_field)				\
+	qr_before_insert(qr_next(a_qrelm, a_field), (a_qr), a_field)
+
+/*
+ * Inverts meld; given the ring:
+ *   a -> a_1 -> ... -> a_n -> b -> b_1 -> ... -> b_n --
+ *   ^                                                 |
+ *   |-------------------------------------------------|
+ *
+ * Results in two rings:
+ *    a -> a_1 -> ... -> a_n --
+ *    ^                       |
+ *    |------------------------
+ *
+ *    b -> b_1 -> ... -> b_n --
+ *    ^                       |
+ *    |------------------------
+ *
+ * qr_meld() and qr_split() are functionally equivalent, so there's no need to
+ * have two copies of the code.
+ */
+#define qr_split(a_qr_a, a_qr_b, a_field)				\
+	qr_meld((a_qr_a), (a_qr_b), a_field)
+
+/*
+ * Splits off a_qr from the rest of its ring, so that it becomes a
+ * single-element ring.
+ */
+#define qr_remove(a_qr, a_field)					\
+	qr_split(qr_next(a_qr, a_field), (a_qr), a_field)
+
+/*
+ * Helper macro to iterate over each element in a ring exactly once, starting
+ * with a_qr.  The usage is (assuming my_t defined as above):
+ *
+ * int sum(my_t *item) {
+ *   int sum = 0;
+ *   my_t *iter;
+ *   qr_foreach(iter, item, link) {
+ *     sum += iter->data;
+ *   }
+ *   return sum;
+ * }
+ */
+#define qr_foreach(var, a_qr, a_field)					\
+	for ((var) = (a_qr);						\
+	    (var) != NULL;						\
+	    (var) = (((var)->a_field.qre_next != (a_qr))		\
+	    ? (var)->a_field.qre_next : NULL))
+
+/*
+ * The same (and with the same usage) as qr_foreach, but in the opposite order,
+ * ending with a_qr.
+ */
+#define qr_reverse_foreach(var, a_qr, a_field)				\
+	for ((var) = ((a_qr) != NULL) ? qr_prev(a_qr, a_field) : NULL;	\
+	    (var) != NULL;						\
+	    (var) = (((var) != (a_qr))					\
+	    ? (var)->a_field.qre_prev : NULL))
+
+#endif /* JEMALLOC_INTERNAL_QR_H */