+++ /dev/null
-/*
- * test-treap.c: code to exercise the svn importer's treap structure
- */
-
-#include "cache.h"
-#include "vcs-svn/obj_pool.h"
-#include "vcs-svn/trp.h"
-
-struct int_node {
- uintmax_t n;
- struct trp_node children;
-};
-
-obj_pool_gen(node, struct int_node, 3)
-
-static int node_cmp(struct int_node *a, struct int_node *b)
-{
- return (a->n > b->n) - (a->n < b->n);
-}
-
-trp_gen(static, treap_, struct int_node, children, node, node_cmp)
-
-static void strtonode(struct int_node *item, const char *s)
-{
- char *end;
- item->n = strtoumax(s, &end, 10);
- if (*s == '\0' || (*end != '\n' && *end != '\0'))
- die("invalid integer: %s", s);
-}
-
-int main(int argc, char *argv[])
-{
- struct strbuf sb = STRBUF_INIT;
- struct trp_root root = { ~0 };
- uint32_t item;
-
- if (argc != 1)
- usage("test-treap < ints");
-
- while (strbuf_getline(&sb, stdin, '\n') != EOF) {
- struct int_node *node = node_pointer(node_alloc(1));
-
- item = node_offset(node);
- strtonode(node, sb.buf);
- node = treap_insert(&root, node_pointer(item));
- if (node_offset(node) != item)
- die("inserted %"PRIu32" in place of %"PRIu32"",
- node_offset(node), item);
- }
-
- item = node_offset(treap_first(&root));
- while (~item) {
- uint32_t next;
- struct int_node *tmp = node_pointer(node_alloc(1));
-
- tmp->n = node_pointer(item)->n;
- next = node_offset(treap_next(&root, node_pointer(item)));
-
- treap_remove(&root, node_pointer(item));
- item = node_offset(treap_nsearch(&root, tmp));
-
- if (item != next && (!~item || node_pointer(item)->n != tmp->n))
- die("found %"PRIuMAX" in place of %"PRIuMAX"",
- ~item ? node_pointer(item)->n : ~(uintmax_t) 0,
- ~next ? node_pointer(next)->n : ~(uintmax_t) 0);
- printf("%"PRIuMAX"\n", tmp->n);
- }
- node_reset();
- return 0;
-}
+++ /dev/null
-/*
- * 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 a_type *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); \
- return trpn_pointer(a_base, 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
+++ /dev/null
-Motivation
-==========
-
-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. The bad worst-case
-behavior is a small price to pay, given that treaps are much simpler
-to implement.
-
-API
-===
-
-The trp API generates a data structure and functions to handle a
-large growing set of objects stored in a pool.
-
-The caller:
-
-. Specifies parameters for the generated functions with the
- trp_gen(static, foo_, ...) macro.
-
-. Allocates a `struct trp_root` variable and sets it to {~0}.
-
-. Adds new nodes to the set using `foo_insert`. Any pointers
- to existing nodes cannot be relied upon any more, so the caller
- might retrieve them anew with `foo_pointer`.
-
-. Can find a specific item in the set using `foo_search`.
-
-. Can iterate over items in the set using `foo_first` and `foo_next`.
-
-. Can remove an item from the set using `foo_remove`.
-
-Example:
-
-----
-struct ex_node {
- const char *s;
- struct trp_node ex_link;
-};
-static struct trp_root ex_base = {~0};
-obj_pool_gen(ex, struct ex_node, 4096);
-trp_gen(static, ex_, struct ex_node, ex_link, ex, strcmp)
-struct ex_node *item;
-
-item = ex_pointer(ex_alloc(1));
-item->s = "hello";
-ex_insert(&ex_base, item);
-item = ex_pointer(ex_alloc(1));
-item->s = "goodbye";
-ex_insert(&ex_base, item);
-for (item = ex_first(&ex_base); item; item = ex_next(&ex_base, item))
- printf("%s\n", item->s);
-----
-
-Functions
----------
-
-trp_gen(attr, foo_, node_type, link_field, pool, cmp)::
-
- Generate a type-specific treap implementation.
-+
-. The storage class for generated functions will be 'attr' (e.g., `static`).
-. Generated function names are prefixed with 'foo_' (e.g., `treap_`).
-. Treap nodes will be of type 'node_type' (e.g., `struct treap_node`).
- This type must be a struct with at least one `struct trp_node` field
- to point to its children.
-. The field used to access child nodes will be 'link_field'.
-. All treap nodes must lie in the 'pool' object pool.
-. Treap nodes must be totally ordered by the 'cmp' relation, with the
- following prototype:
-+
-int (*cmp)(node_type \*a, node_type \*b)
-+
-and returning a value less than, equal to, or greater than zero
-according to the result of comparison.
-
-node_type {asterisk}foo_insert(struct trp_root *treap, node_type \*node)::
-
- Insert node into treap. If inserted multiple times,
- a node will appear in the treap multiple times.
-+
-The return value is the address of the node within the treap,
-which might differ from `node` if `pool_alloc` had to call
-`realloc` to expand the pool.
-
-void foo_remove(struct trp_root *treap, node_type \*node)::
-
- Remove node from treap. Caller must ensure node is
- present in treap before using this function.
-
-node_type *foo_search(struct trp_root \*treap, node_type \*key)::
-
- Search for a node that matches key. If no match is found,
- result is NULL.
-
-node_type *foo_nsearch(struct trp_root \*treap, node_type \*key)::
-
- Like `foo_search`, but if if the key is missing return what
- would be key's successor, were key in treap (NULL if no
- successor).
-
-node_type *foo_first(struct trp_root \*treap)::
-
- Find the first item from the treap, in sorted order.
-
-node_type *foo_next(struct trp_root \*treap, node_type \*node)::
-
- Find the next item.
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