Code

Add treap implementation
[git.git] / vcs-svn / trp.h
diff --git a/vcs-svn/trp.h b/vcs-svn/trp.h
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+/*
+ * C macro implementation of treaps.
+ *
+ * Usage:
+ *   #include <stdint.h>
+ *   #include "trp.h"
+ *   trp_gen(...)
+ *
+ * Licensed under a two-clause BSD-style license.
+ * See LICENSE for details.
+ */
+
+#ifndef TRP_H_
+#define TRP_H_
+
+#define MAYBE_UNUSED __attribute__((__unused__))
+
+/* Node structure. */
+struct trp_node {
+       uint32_t trpn_left;
+       uint32_t trpn_right;
+};
+
+/* Root structure. */
+struct trp_root {
+       uint32_t trp_root;
+};
+
+/* Pointer/Offset conversion. */
+#define trpn_pointer(a_base, a_offset) (a_base##_pointer(a_offset))
+#define trpn_offset(a_base, a_pointer) (a_base##_offset(a_pointer))
+#define trpn_modify(a_base, a_offset) \
+       do { \
+               if ((a_offset) < a_base##_pool.committed) { \
+                       uint32_t old_offset = (a_offset);\
+                       (a_offset) = a_base##_alloc(1); \
+                       *trpn_pointer(a_base, a_offset) = \
+                               *trpn_pointer(a_base, old_offset); \
+               } \
+       } while (0);
+
+/* Left accessors. */
+#define trp_left_get(a_base, a_field, a_node) \
+       (trpn_pointer(a_base, a_node)->a_field.trpn_left)
+#define trp_left_set(a_base, a_field, a_node, a_left) \
+       do { \
+               trpn_modify(a_base, a_node); \
+               trp_left_get(a_base, a_field, a_node) = (a_left); \
+       } while(0)
+
+/* Right accessors. */
+#define trp_right_get(a_base, a_field, a_node) \
+       (trpn_pointer(a_base, a_node)->a_field.trpn_right)
+#define trp_right_set(a_base, a_field, a_node, a_right) \
+       do { \
+               trpn_modify(a_base, a_node); \
+               trp_right_get(a_base, a_field, a_node) = (a_right); \
+       } while(0)
+
+/*
+ * Fibonacci hash function.
+ * The multiplier is the nearest prime to (2^32 times (√5 - 1)/2).
+ * See Knuth §6.4: volume 3, 3rd ed, p518.
+ */
+#define trpn_hash(a_node) (uint32_t) (2654435761u * (a_node))
+
+/* Priority accessors. */
+#define trp_prio_get(a_node) trpn_hash(a_node)
+
+/* Node initializer. */
+#define trp_node_new(a_base, a_field, a_node) \
+       do { \
+               trp_left_set(a_base, a_field, (a_node), ~0); \
+               trp_right_set(a_base, a_field, (a_node), ~0); \
+       } while(0)
+
+/* Internal utility macros. */
+#define trpn_first(a_base, a_field, a_root, r_node) \
+       do { \
+               (r_node) = (a_root); \
+               if ((r_node) == ~0) \
+                       return NULL; \
+               while (~trp_left_get(a_base, a_field, (r_node))) \
+                       (r_node) = trp_left_get(a_base, a_field, (r_node)); \
+       } while (0)
+
+#define trpn_rotate_left(a_base, a_field, a_node, r_node) \
+       do { \
+               (r_node) = trp_right_get(a_base, a_field, (a_node)); \
+               trp_right_set(a_base, a_field, (a_node), \
+                       trp_left_get(a_base, a_field, (r_node))); \
+               trp_left_set(a_base, a_field, (r_node), (a_node)); \
+       } while(0)
+
+#define trpn_rotate_right(a_base, a_field, a_node, r_node) \
+       do { \
+               (r_node) = trp_left_get(a_base, a_field, (a_node)); \
+               trp_left_set(a_base, a_field, (a_node), \
+                       trp_right_get(a_base, a_field, (r_node))); \
+               trp_right_set(a_base, a_field, (r_node), (a_node)); \
+       } while(0)
+
+#define trp_gen(a_attr, a_pre, a_type, a_field, a_base, a_cmp) \
+a_attr a_type MAYBE_UNUSED *a_pre##first(struct trp_root *treap) \
+{ \
+       uint32_t ret; \
+       trpn_first(a_base, a_field, treap->trp_root, ret); \
+       return trpn_pointer(a_base, ret); \
+} \
+a_attr a_type MAYBE_UNUSED *a_pre##next(struct trp_root *treap, a_type *node) \
+{ \
+       uint32_t ret; \
+       uint32_t offset = trpn_offset(a_base, node); \
+       if (~trp_right_get(a_base, a_field, offset)) { \
+               trpn_first(a_base, a_field, \
+                       trp_right_get(a_base, a_field, offset), ret); \
+       } else { \
+               uint32_t tnode = treap->trp_root; \
+               ret = ~0; \
+               while (1) { \
+                       int cmp = (a_cmp)(trpn_pointer(a_base, offset), \
+                               trpn_pointer(a_base, tnode)); \
+                       if (cmp < 0) { \
+                               ret = tnode; \
+                               tnode = trp_left_get(a_base, a_field, tnode); \
+                       } else if (cmp > 0) { \
+                               tnode = trp_right_get(a_base, a_field, tnode); \
+                       } else { \
+                               break; \
+                       } \
+               } \
+       } \
+       return trpn_pointer(a_base, ret); \
+} \
+a_attr a_type MAYBE_UNUSED *a_pre##search(struct trp_root *treap, a_type *key) \
+{ \
+       int cmp; \
+       uint32_t ret = treap->trp_root; \
+       while (~ret && (cmp = (a_cmp)(key, trpn_pointer(a_base,ret)))) { \
+               if (cmp < 0) { \
+                       ret = trp_left_get(a_base, a_field, ret); \
+               } else { \
+                       ret = trp_right_get(a_base, a_field, ret); \
+               } \
+       } \
+       return trpn_pointer(a_base, ret); \
+} \
+a_attr a_type MAYBE_UNUSED *a_pre##nsearch(struct trp_root *treap, a_type *key) \
+{ \
+       int cmp; \
+       uint32_t ret = treap->trp_root; \
+       while (~ret && (cmp = (a_cmp)(key, trpn_pointer(a_base,ret)))) { \
+               if (cmp < 0) { \
+                       if (!~trp_left_get(a_base, a_field, ret)) \
+                               break; \
+                       ret = trp_left_get(a_base, a_field, ret); \
+               } else { \
+                       ret = trp_right_get(a_base, a_field, ret); \
+               } \
+       } \
+       return trpn_pointer(a_base, ret); \
+} \
+a_attr uint32_t MAYBE_UNUSED a_pre##insert_recurse(uint32_t cur_node, uint32_t ins_node) \
+{ \
+       if (cur_node == ~0) { \
+               return (ins_node); \
+       } else { \
+               uint32_t ret; \
+               int cmp = (a_cmp)(trpn_pointer(a_base, ins_node), \
+                                       trpn_pointer(a_base, cur_node)); \
+               if (cmp < 0) { \
+                       uint32_t left = a_pre##insert_recurse( \
+                               trp_left_get(a_base, a_field, cur_node), ins_node); \
+                       trp_left_set(a_base, a_field, cur_node, left); \
+                       if (trp_prio_get(left) < trp_prio_get(cur_node)) \
+                               trpn_rotate_right(a_base, a_field, cur_node, ret); \
+                       else \
+                               ret = cur_node; \
+               } else { \
+                       uint32_t right = a_pre##insert_recurse( \
+                               trp_right_get(a_base, a_field, cur_node), ins_node); \
+                       trp_right_set(a_base, a_field, cur_node, right); \
+                       if (trp_prio_get(right) < trp_prio_get(cur_node)) \
+                               trpn_rotate_left(a_base, a_field, cur_node, ret); \
+                       else \
+                               ret = cur_node; \
+               } \
+               return (ret); \
+       } \
+} \
+a_attr void MAYBE_UNUSED a_pre##insert(struct trp_root *treap, a_type *node) \
+{ \
+       uint32_t offset = trpn_offset(a_base, node); \
+       trp_node_new(a_base, a_field, offset); \
+       treap->trp_root = a_pre##insert_recurse(treap->trp_root, offset); \
+} \
+a_attr uint32_t MAYBE_UNUSED a_pre##remove_recurse(uint32_t cur_node, uint32_t rem_node) \
+{ \
+       int cmp = a_cmp(trpn_pointer(a_base, rem_node), \
+                       trpn_pointer(a_base, cur_node)); \
+       if (cmp == 0) { \
+               uint32_t ret; \
+               uint32_t left = trp_left_get(a_base, a_field, cur_node); \
+               uint32_t right = trp_right_get(a_base, a_field, cur_node); \
+               if (left == ~0) { \
+                       if (right == ~0) \
+                               return (~0); \
+               } else if (right == ~0 || trp_prio_get(left) < trp_prio_get(right)) { \
+                       trpn_rotate_right(a_base, a_field, cur_node, ret); \
+                       right = a_pre##remove_recurse(cur_node, rem_node); \
+                       trp_right_set(a_base, a_field, ret, right); \
+                       return (ret); \
+               } \
+               trpn_rotate_left(a_base, a_field, cur_node, ret); \
+               left = a_pre##remove_recurse(cur_node, rem_node); \
+               trp_left_set(a_base, a_field, ret, left); \
+               return (ret); \
+       } else if (cmp < 0) { \
+               uint32_t left = a_pre##remove_recurse( \
+                       trp_left_get(a_base, a_field, cur_node), rem_node); \
+               trp_left_set(a_base, a_field, cur_node, left); \
+               return (cur_node); \
+       } else { \
+               uint32_t right = a_pre##remove_recurse( \
+                       trp_right_get(a_base, a_field, cur_node), rem_node); \
+               trp_right_set(a_base, a_field, cur_node, right); \
+               return (cur_node); \
+       } \
+} \
+a_attr void MAYBE_UNUSED a_pre##remove(struct trp_root *treap, a_type *node) \
+{ \
+       treap->trp_root = a_pre##remove_recurse(treap->trp_root, \
+               trpn_offset(a_base, node)); \
+} \
+
+#endif