[PATCH 2/6] Add cpp macro implementation of treaps
- From
Ramkumar Ramachandra <artagnon@gmail.com>
- Date
- Jun 10, 2010, 13:09 UTC
- Message-ID
- <1276175389-6185-3-git-send-email-artagnon@gmail.com>
- In-Reply-To
- <1276175389-6185-1-git-send-email-artagnon@gmail.com>
From: Jason Evans <jasone@canonware.com>
The implementation exposes an API to generate type-specific treap implmentation and various functions to operate on it. It uses obj_pool.h to store memory nodes in a treap.
Treaps provide a memory-efficient binary search tree structure. Insertion/deletion/search are about as about as fast in the average case as red-black trees and the chances of worst-case behavior are vanishingly small, thanks to (pseudo-)randomness. That is a small price to pay, given that treaps are much simpler to implement.
[db: Altered to reference nodes by offset from a common base pointer] [db: Bob Jenkins' hashing implementation dropped for Knuth's] [db: Methods unnecessary for search and insert dropped]
Signed-off-by: David Barr <david.barr@cordelta.com> Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com> --- vcs-svn/trp.h | 201 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ vcs-svn/trp.txt | 61 +++++++++++++++++ 2 files changed, 262 insertions(+), 0 deletions(-) create mode 100644 vcs-svn/trp.h create mode 100644 vcs-svn/trp.txt
diff --git a/vcs-svn/trp.h b/vcs-svn/trp.h new file mode 100644 index 0000000..50fde39 --- /dev/null +++ b/vcs-svn/trp.h @@ -0,0 +1,201 @@ +/* + * cpp 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_ + +/* 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) + +/* Priority accessors. */ +#define KNUTH_GOLDEN_RATIO_32BIT 2654435761u +#define trp_prio_get(a_node) \ + (KNUTH_GOLDEN_RATIO_32BIT*(a_node)) + +/* Node initializer. */ +#define trp_node_new(a_base, a_field, a_node) \ + trp_left_set(a_base, a_field, (a_node), ~0); \ + trp_right_set(a_base, a_field, (a_node), ~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 *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 *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 *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 uint32_t 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 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 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 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 diff --git a/vcs-svn/trp.txt b/vcs-svn/trp.txt new file mode 100644 index 0000000..b7e2d18 --- /dev/null +++ b/vcs-svn/trp.txt @@ -0,0 +1,61 @@ +TODO: Update this documentation to match the changes to trp.h + +The trp_gen() macro generates a type-specific treap implementation, +based on the above cpp macros. + +Arguments: + + a_attr : Function attribute for generated functions (ex: static). + a_pre : Prefix for generated functions (ex: treap_). + a_t_type : Type for treap data structure (ex: treap_t). + a_type : Type for treap node data structure (ex: treap_node_t). + a_field : Name of treap node linkage (ex: treap_link). + a_base : Expression for the base pointer from which nodes are offset. + a_cmp : Node comparison function name, with the following prototype: + int (a_cmp *)(a_type *a_node, a_type *a_other); + ^^^^^^ + or a_key + Interpretation of comparision function return values: + -1 : a_node < a_other + 0 : a_node == a_other + 1 : a_node > a_other + In all cases, the a_node or a_key macro argument is the first + argument to the comparison function, which makes it possible + to write comparison functions that treat the first argument + specially. + +Assuming the following setup: + + typedef struct ex_node_s ex_node_t; + struct ex_node_s { + trp_node(ex_node_t) ex_link; + }; + typedef trp(ex_node_t) ex_t; + static ex_node_t ex_base[MAX_NODES]; + trp_gen(static, ex_, ex_t, ex_node_t, ex_link, ex_base, ex_cmp) + +The following API is generated: + + static void + ex_new(ex_t *treap); + Description: Initialize a treap structure. + Args: + treap: Pointer to an uninitialized treap object. + + static ex_node_t * + ex_psearch(ex_t *treap, ex_node_t *key); + Description: Search for node that matches key. If no match is found, + return what would be key's successor/predecessor, were + key in treap. + Args: + treap: Pointer to a initialized treap object. + key : Search key. + Ret: Node in treap that matches key, or if no match, hypothetical + node's successor/predecessor (NULL if no successor/predecessor). + + static void + ex_insert(ex_t *treap, ex_node_t *node); + Description: Insert node into treap. + Args: + treap: Pointer to a initialized treap object. + node : Node to be inserted into treap.
-- 1.7.1