Pairing heap

Initial implementation of a twopass pairing heap with aux list.
Research papers linked in comments.

Where search/nsearch/last aren't needed, this gives much faster first(),
delete(), and insert().  Insert is O(1), and first/delete don't have to
walk the whole tree.

Also tested rb_old with parent pointers - it was better than the current
rb.h for memory loads, but still much worse than a pairing heap.

An array-based heap would be much faster if everything fits in memory,
but on a cold cache it has many more memory loads for most operations.

1 files changed, 2 insertions, 0 deletions

diff --git a/src/ph.c b/src/ph.c
new file mode 100644
index 0000000..051a20d
--- /dev/null
+++ b/src/ph.c
@@ -0,0 +1,2 @@
+#define	JEMALLOC_PH_C_
+#include "jemalloc/internal/jemalloc_internal.h"