2 * Copyright (c) 1990, 1993, 1994
3 * The Regents of the University of California. All rights reserved.
5 * This code is derived from software contributed to Berkeley by
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33 #if defined(LIBC_SCCS) && !defined(lint)
34 static char sccsid[] = "@(#)bt_utils.c 8.8 (Berkeley) 7/20/94";
35 #endif /* LIBC_SCCS and not lint */
36 #include <sys/cdefs.h>
37 __FBSDID("$FreeBSD$");
39 #include <sys/param.h>
50 * Build return key/data pair.
54 * e: key/data pair to be returned
55 * key: user's key structure (NULL if not to be filled in)
56 * rkey: memory area to hold key
57 * data: user's data structure (NULL if not to be filled in)
58 * rdata: memory area to hold data
59 * copy: always copy the key/data item
62 * RET_SUCCESS, RET_ERROR.
65 __bt_ret(t, e, key, rkey, data, rdata, copy)
68 DBT *key, *rkey, *data, *rdata;
74 bl = GETBLEAF(e->page, e->index);
77 * We must copy big keys/data to make them contigous. Otherwise,
78 * leave the page pinned and don't copy unless the user specified
84 if (bl->flags & P_BIGKEY) {
85 if (__ovfl_get(t, bl->bytes,
86 &key->size, &rkey->data, &rkey->size))
88 key->data = rkey->data;
89 } else if (copy || F_ISSET(t, B_DB_LOCK)) {
90 if (bl->ksize > rkey->size) {
91 p = (void *)(rkey->data == NULL ?
92 malloc(bl->ksize) : realloc(rkey->data, bl->ksize));
96 rkey->size = bl->ksize;
98 memmove(rkey->data, bl->bytes, bl->ksize);
99 key->size = bl->ksize;
100 key->data = rkey->data;
102 key->size = bl->ksize;
103 key->data = bl->bytes;
108 return (RET_SUCCESS);
110 if (bl->flags & P_BIGDATA) {
111 if (__ovfl_get(t, bl->bytes + bl->ksize,
112 &data->size, &rdata->data, &rdata->size))
114 data->data = rdata->data;
115 } else if (copy || F_ISSET(t, B_DB_LOCK)) {
116 /* Use +1 in case the first record retrieved is 0 length. */
117 if (bl->dsize + 1 > rdata->size) {
118 p = (void *)(rdata->data == NULL ?
119 malloc(bl->dsize + 1) :
120 realloc(rdata->data, bl->dsize + 1));
124 rdata->size = bl->dsize + 1;
126 memmove(rdata->data, bl->bytes + bl->ksize, bl->dsize);
127 data->size = bl->dsize;
128 data->data = rdata->data;
130 data->size = bl->dsize;
131 data->data = bl->bytes + bl->ksize;
134 return (RET_SUCCESS);
138 * __BT_CMP -- Compare a key to a given record.
142 * k1: DBT pointer of first arg to comparison
143 * e: pointer to EPG for comparison
146 * < 0 if k1 is < record
147 * = 0 if k1 is = record
148 * > 0 if k1 is > record
163 * The left-most key on internal pages, at any level of the tree, is
164 * guaranteed by the following code to be less than any user key.
165 * This saves us from having to update the leftmost key on an internal
166 * page when the user inserts a new key in the tree smaller than
167 * anything we've yet seen.
170 if (e->index == 0 && h->prevpg == P_INVALID && !(h->flags & P_BLEAF))
174 if (h->flags & P_BLEAF) {
175 bl = GETBLEAF(h, e->index);
176 if (bl->flags & P_BIGKEY)
183 bi = GETBINTERNAL(h, e->index);
184 if (bi->flags & P_BIGKEY)
193 if (__ovfl_get(t, bigkey,
194 &k2.size, &t->bt_rdata.data, &t->bt_rdata.size))
196 k2.data = t->bt_rdata.data;
198 return ((*t->bt_cmp)(k1, &k2));
202 * __BT_DEFCMP -- Default comparison routine.
222 * If a size_t doesn't fit in an int, this routine can lose.
223 * What we need is an integral type which is guaranteed to be
224 * larger than a size_t, and there is no such thing.
226 len = MIN(a->size, b->size);
227 for (p1 = a->data, p2 = b->data; len--; ++p1, ++p2)
229 return ((int)*p1 - (int)*p2);
230 return ((int)a->size - (int)b->size);
234 * __BT_DEFPFX -- Default prefix routine.
241 * Number of bytes needed to distinguish b from a.
251 len = MIN(a->size, b->size);
252 for (p1 = a->data, p2 = b->data; len--; ++p1, ++p2, ++cnt)
256 /* a->size must be <= b->size, or they wouldn't be in this order. */
257 return (a->size < b->size ? a->size + 1 : a->size);