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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(BTREE *t, EPG *e, DBT *key, DBT *rkey, DBT *data, DBT *rdata, int copy)
70 bl = GETBLEAF(e->page, e->index);
73 * We must copy big keys/data to make them contigous. Otherwise,
74 * leave the page pinned and don't copy unless the user specified
80 if (bl->flags & P_BIGKEY) {
81 if (__ovfl_get(t, bl->bytes,
82 &key->size, &rkey->data, &rkey->size))
84 key->data = rkey->data;
85 } else if (copy || F_ISSET(t, B_DB_LOCK)) {
86 if (bl->ksize > rkey->size) {
87 p = realloc(rkey->data, bl->ksize);
91 rkey->size = bl->ksize;
93 memmove(rkey->data, bl->bytes, bl->ksize);
94 key->size = bl->ksize;
95 key->data = rkey->data;
97 key->size = bl->ksize;
98 key->data = bl->bytes;
103 return (RET_SUCCESS);
105 if (bl->flags & P_BIGDATA) {
106 if (__ovfl_get(t, bl->bytes + bl->ksize,
107 &data->size, &rdata->data, &rdata->size))
109 data->data = rdata->data;
110 } else if (copy || F_ISSET(t, B_DB_LOCK)) {
111 /* Use +1 in case the first record retrieved is 0 length. */
112 if (bl->dsize + 1 > rdata->size) {
113 p = realloc(rdata->data, bl->dsize + 1);
117 rdata->size = bl->dsize + 1;
119 memmove(rdata->data, bl->bytes + bl->ksize, bl->dsize);
120 data->size = bl->dsize;
121 data->data = rdata->data;
123 data->size = bl->dsize;
124 data->data = bl->bytes + bl->ksize;
127 return (RET_SUCCESS);
131 * __BT_CMP -- Compare a key to a given record.
135 * k1: DBT pointer of first arg to comparison
136 * e: pointer to EPG for comparison
139 * < 0 if k1 is < record
140 * = 0 if k1 is = record
141 * > 0 if k1 is > record
144 __bt_cmp(BTREE *t, const DBT *k1, EPG *e)
153 * The left-most key on internal pages, at any level of the tree, is
154 * guaranteed by the following code to be less than any user key.
155 * This saves us from having to update the leftmost key on an internal
156 * page when the user inserts a new key in the tree smaller than
157 * anything we've yet seen.
160 if (e->index == 0 && h->prevpg == P_INVALID && !(h->flags & P_BLEAF))
164 if (h->flags & P_BLEAF) {
165 bl = GETBLEAF(h, e->index);
166 if (bl->flags & P_BIGKEY)
173 bi = GETBINTERNAL(h, e->index);
174 if (bi->flags & P_BIGKEY)
183 if (__ovfl_get(t, bigkey,
184 &k2.size, &t->bt_rdata.data, &t->bt_rdata.size))
186 k2.data = t->bt_rdata.data;
188 return ((*t->bt_cmp)(k1, &k2));
192 * __BT_DEFCMP -- Default comparison routine.
204 __bt_defcmp(const DBT *a, const DBT *b)
211 * If a size_t doesn't fit in an int, this routine can lose.
212 * What we need is an integral type which is guaranteed to be
213 * larger than a size_t, and there is no such thing.
215 len = MIN(a->size, b->size);
216 for (p1 = a->data, p2 = b->data; len--; ++p1, ++p2)
218 return ((int)*p1 - (int)*p2);
219 return ((int)a->size - (int)b->size);
223 * __BT_DEFPFX -- Default prefix routine.
230 * Number of bytes needed to distinguish b from a.
233 __bt_defpfx(const DBT *a, const DBT *b)
239 len = MIN(a->size, b->size);
240 for (p1 = a->data, p2 = b->data; len--; ++p1, ++p2, ++cnt)
244 /* a->size must be <= b->size, or they wouldn't be in this order. */
245 return (a->size < b->size ? a->size + 1 : a->size);