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git://sourceware.org/git/lvm2.git
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8ef2b021ed
Clear many compiler warnings (i386) & associated bugs - hopefully without introducing too many new bugs:-) (Same exercise required for other archs.) Default compilation has optimisation - or else use ./configure --enable-debug
130 lines
1.9 KiB
C
130 lines
1.9 KiB
C
/*
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* Copyright (C) 2001 Sistina Software (UK) Limited.
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*
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* This file is released under the LGPL.
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*/
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#include "lib.h"
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#include "btree.h"
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struct node {
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uint32_t key;
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struct node *l, *r, *p;
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void *data;
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};
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struct btree {
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struct pool *mem;
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struct node *root;
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};
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struct btree *btree_create(struct pool *mem)
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{
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struct btree *t = pool_alloc(mem, sizeof(*t));
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if (t) {
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t->mem = mem;
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t->root = NULL;
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}
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return t;
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}
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/*
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* Shuffle the bits in a key, to try and remove
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* any ordering.
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*/
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static uint32_t _shuffle(uint32_t k)
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{
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#if 1
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return ((k & 0xff) << 24 |
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(k & 0xff00) << 8 |
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(k & 0xff0000) >> 8 | (k & 0xff000000) >> 24);
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#else
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return k;
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#endif
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}
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static struct node **_lookup(struct node **c, uint32_t key, struct node **p)
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{
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*p = NULL;
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while (*c) {
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*p = *c;
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if ((*c)->key == key)
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break;
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if (key < (*c)->key)
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c = &(*c)->l;
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else
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c = &(*c)->r;
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}
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return c;
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}
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void *btree_lookup(struct btree *t, uint32_t k)
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{
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uint32_t key = _shuffle(k);
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struct node *p, **c = _lookup(&t->root, key, &p);
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return (*c) ? (*c)->data : NULL;
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}
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int btree_insert(struct btree *t, uint32_t k, void *data)
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{
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uint32_t key = _shuffle(k);
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struct node *p, **c = _lookup(&t->root, key, &p), *n;
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if (!*c) {
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if (!(n = pool_alloc(t->mem, sizeof(*n)))) {
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stack;
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return 0;
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}
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n->key = key;
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n->data = data;
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n->l = n->r = NULL;
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n->p = p;
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*c = n;
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}
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return 1;
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}
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void *btree_get_data(struct btree_iter *it)
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{
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return ((struct node *) it)->data;
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}
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static inline struct node *_left(struct node *n)
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{
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while (n->l)
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n = n->l;
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return n;
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}
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struct btree_iter *btree_first(struct btree *t)
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{
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if (!t->root)
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return NULL;
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return (struct btree_iter *) _left(t->root);
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}
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struct btree_iter *btree_next(struct btree_iter *it)
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{
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struct node *n = (struct node *) it;
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uint32_t k = n->key;
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if (n->r)
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return (struct btree_iter *) _left(n->r);
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do
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n = n->p;
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while (n && k > n->key);
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return (struct btree_iter *) n;
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}
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