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