/* $OpenBSD: bt_utils.c,v 1.13 2022/12/27 17:10:06 jmc Exp $ */ /*- * Copyright (c) 1990, 1993, 1994 * The Regents of the University of California. All rights reserved. * * This code is derived from software contributed to Berkeley by * Mike Olson. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include #include #include #include #include "btree.h" #define MINIMUM(a, b) (((a) < (b)) ? (a) : (b)) /* * __bt_ret -- * Build return key/data pair. * * Parameters: * t: tree * e: key/data pair to be returned * key: user's key structure (NULL if not to be filled in) * rkey: memory area to hold key * data: user's data structure (NULL if not to be filled in) * rdata: memory area to hold data * copy: always copy the key/data item * * Returns: * RET_SUCCESS, RET_ERROR. */ int __bt_ret(BTREE *t, EPG *e, DBT *key, DBT *rkey, DBT *data, DBT *rdata, int copy) { BLEAF *bl; void *p; bl = GETBLEAF(e->page, e->index); /* * We must copy big keys/data to make them contiguous. Otherwise, * leave the page pinned and don't copy unless the user specified * concurrent access. */ if (key == NULL) goto dataonly; if (bl->flags & P_BIGKEY) { if (__ovfl_get(t, bl->bytes, &key->size, &rkey->data, &rkey->size)) return (RET_ERROR); key->data = rkey->data; } else if (copy || F_ISSET(t, B_DB_LOCK)) { if (bl->ksize > rkey->size) { p = realloc(rkey->data, bl->ksize); if (p == NULL) return (RET_ERROR); rkey->data = p; rkey->size = bl->ksize; } memmove(rkey->data, bl->bytes, bl->ksize); key->size = bl->ksize; key->data = rkey->data; } else { key->size = bl->ksize; key->data = bl->bytes; } dataonly: if (data == NULL) return (RET_SUCCESS); if (bl->flags & P_BIGDATA) { if (__ovfl_get(t, bl->bytes + bl->ksize, &data->size, &rdata->data, &rdata->size)) return (RET_ERROR); data->data = rdata->data; } else if (copy || F_ISSET(t, B_DB_LOCK)) { /* Use +1 in case the first record retrieved is 0 length. */ if (bl->dsize + 1 > rdata->size) { p = realloc(rdata->data, bl->dsize + 1); if (p == NULL) return (RET_ERROR); rdata->data = p; rdata->size = bl->dsize + 1; } memmove(rdata->data, bl->bytes + bl->ksize, bl->dsize); data->size = bl->dsize; data->data = rdata->data; } else { data->size = bl->dsize; data->data = bl->bytes + bl->ksize; } return (RET_SUCCESS); } /* * __BT_CMP -- Compare a key to a given record. * * Parameters: * t: tree * k1: DBT pointer of first arg to comparison * e: pointer to EPG for comparison * * Returns: * < 0 if k1 is < record * = 0 if k1 is = record * > 0 if k1 is > record */ int __bt_cmp(BTREE *t, const DBT *k1, EPG *e) { BINTERNAL *bi; BLEAF *bl; DBT k2; PAGE *h; void *bigkey; /* * The left-most key on internal pages, at any level of the tree, is * guaranteed by the following code to be less than any user key. * This saves us from having to update the leftmost key on an internal * page when the user inserts a new key in the tree smaller than * anything we've yet seen. */ h = e->page; if (e->index == 0 && h->prevpg == P_INVALID && !(h->flags & P_BLEAF)) return (1); bigkey = NULL; if (h->flags & P_BLEAF) { bl = GETBLEAF(h, e->index); if (bl->flags & P_BIGKEY) bigkey = bl->bytes; else { k2.data = bl->bytes; k2.size = bl->ksize; } } else { bi = GETBINTERNAL(h, e->index); if (bi->flags & P_BIGKEY) bigkey = bi->bytes; else { k2.data = bi->bytes; k2.size = bi->ksize; } } if (bigkey) { if (__ovfl_get(t, bigkey, &k2.size, &t->bt_rdata.data, &t->bt_rdata.size)) return (RET_ERROR); k2.data = t->bt_rdata.data; } return ((*t->bt_cmp)(k1, &k2)); } /* * __BT_DEFCMP -- Default comparison routine. * * Parameters: * a: DBT #1 * b: DBT #2 * * Returns: * < 0 if a is < b * = 0 if a is = b * > 0 if a is > b */ int __bt_defcmp(const DBT *a, const DBT *b) { size_t len; u_char *p1, *p2; /* * XXX * If a size_t doesn't fit in an int, this routine can lose. * What we need is a integral type which is guaranteed to be * larger than a size_t, and there is no such thing. */ len = MINIMUM(a->size, b->size); for (p1 = a->data, p2 = b->data; len--; ++p1, ++p2) if (*p1 != *p2) return ((int)*p1 - (int)*p2); return ((int)a->size - (int)b->size); } /* * __BT_DEFPFX -- Default prefix routine. * * Parameters: * a: DBT #1 * b: DBT #2 * * Returns: * Number of bytes needed to distinguish b from a. */ size_t __bt_defpfx(const DBT *a, const DBT *b) { u_char *p1, *p2; size_t cnt, len; cnt = 1; len = MINIMUM(a->size, b->size); for (p1 = a->data, p2 = b->data; len--; ++p1, ++p2, ++cnt) if (*p1 != *p2) return (cnt); /* a->size must be <= b->size, or they wouldn't be in this order. */ return (a->size < b->size ? a->size + 1 : a->size); }