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1/*2 * linux/fs/befs/btree.c3 *4 * Copyright (C) 2001-2002 Will Dyson <will_dyson@pobox.com>5 *6 * Licensed under the GNU GPL. See the file COPYING for details.7 *8 * 2002-02-05: Sergey S. Kostyliov added binary search within9 * btree nodes.10 *11 * Many thanks to:12 *13 * Dominic Giampaolo, author of "Practical File System14 * Design with the Be File System", for such a helpful book.15 *16 * Marcus J. Ranum, author of the b+tree package in17 * comp.sources.misc volume 10. This code is not copied from that18 * work, but it is partially based on it.19 *20 * Makoto Kato, author of the original BeFS for linux filesystem21 * driver.22 */23 24#include <linux/kernel.h>25#include <linux/string.h>26#include <linux/slab.h>27#include <linux/mm.h>28#include <linux/buffer_head.h>29 30#include "befs.h"31#include "btree.h"32#include "datastream.h"33 34/*35 * The btree functions in this file are built on top of the36 * datastream.c interface, which is in turn built on top of the37 * io.c interface.38 */39 40/* Befs B+tree structure:41 *42 * The first thing in the tree is the tree superblock. It tells you43 * all kinds of useful things about the tree, like where the rootnode44 * is located, and the size of the nodes (always 1024 with current version45 * of BeOS).46 *47 * The rest of the tree consists of a series of nodes. Nodes contain a header48 * (struct befs_btree_nodehead), the packed key data, an array of shorts49 * containing the ending offsets for each of the keys, and an array of50 * befs_off_t values. In interior nodes, the keys are the ending keys for51 * the childnode they point to, and the values are offsets into the52 * datastream containing the tree.53 */54 55/* Note:56 *57 * The book states 2 confusing things about befs b+trees. First,58 * it states that the overflow field of node headers is used by internal nodes59 * to point to another node that "effectively continues this one". Here is what60 * I believe that means. Each key in internal nodes points to another node that61 * contains key values less than itself. Inspection reveals that the last key62 * in the internal node is not the last key in the index. Keys that are63 * greater than the last key in the internal node go into the overflow node.64 * I imagine there is a performance reason for this.65 *66 * Second, it states that the header of a btree node is sufficient to67 * distinguish internal nodes from leaf nodes. Without saying exactly how.68 * After figuring out the first, it becomes obvious that internal nodes have69 * overflow nodes and leafnodes do not.70 */71 72/*73 * Currently, this code is only good for directory B+trees.74 * In order to be used for other BFS indexes, it needs to be extended to handle75 * duplicate keys and non-string keytypes (int32, int64, float, double).76 */77 78/*79 * In memory structure of each btree node80 */81struct befs_btree_node {82 befs_host_btree_nodehead head; /* head of node converted to cpu byteorder */83 struct buffer_head *bh;84 befs_btree_nodehead *od_node; /* on disk node */85};86 87/* local constants */88static const befs_off_t BEFS_BT_INVAL = 0xffffffffffffffffULL;89 90/* local functions */91static int befs_btree_seekleaf(struct super_block *sb, const befs_data_stream *ds,92 befs_btree_super * bt_super,93 struct befs_btree_node *this_node,94 befs_off_t * node_off);95 96static int befs_bt_read_super(struct super_block *sb, const befs_data_stream *ds,97 befs_btree_super * sup);98 99static int befs_bt_read_node(struct super_block *sb, const befs_data_stream *ds,100 struct befs_btree_node *node,101 befs_off_t node_off);102 103static int befs_leafnode(struct befs_btree_node *node);104 105static fs16 *befs_bt_keylen_index(struct befs_btree_node *node);106 107static fs64 *befs_bt_valarray(struct befs_btree_node *node);108 109static char *befs_bt_keydata(struct befs_btree_node *node);110 111static int befs_find_key(struct super_block *sb,112 struct befs_btree_node *node,113 const char *findkey, befs_off_t * value);114 115static char *befs_bt_get_key(struct super_block *sb,116 struct befs_btree_node *node,117 int index, u16 * keylen);118 119static int befs_compare_strings(const void *key1, int keylen1,120 const void *key2, int keylen2);121 122/**123 * befs_bt_read_super() - read in btree superblock convert to cpu byteorder124 * @sb: Filesystem superblock125 * @ds: Datastream to read from126 * @sup: Buffer in which to place the btree superblock127 *128 * Calls befs_read_datastream to read in the btree superblock and129 * makes sure it is in cpu byteorder, byteswapping if necessary.130 * Return: BEFS_OK on success and if *@sup contains the btree superblock in cpu131 * byte order. Otherwise return BEFS_ERR on error.132 */133static int134befs_bt_read_super(struct super_block *sb, const befs_data_stream *ds,135 befs_btree_super * sup)136{137 struct buffer_head *bh;138 befs_disk_btree_super *od_sup;139 140 befs_debug(sb, "---> %s", __func__);141 142 bh = befs_read_datastream(sb, ds, 0, NULL);143 144 if (!bh) {145 befs_error(sb, "Couldn't read index header.");146 goto error;147 }148 od_sup = (befs_disk_btree_super *) bh->b_data;149 befs_dump_index_entry(sb, od_sup);150 151 sup->magic = fs32_to_cpu(sb, od_sup->magic);152 sup->node_size = fs32_to_cpu(sb, od_sup->node_size);153 sup->max_depth = fs32_to_cpu(sb, od_sup->max_depth);154 sup->data_type = fs32_to_cpu(sb, od_sup->data_type);155 sup->root_node_ptr = fs64_to_cpu(sb, od_sup->root_node_ptr);156 157 brelse(bh);158 if (sup->magic != BEFS_BTREE_MAGIC) {159 befs_error(sb, "Index header has bad magic.");160 goto error;161 }162 163 befs_debug(sb, "<--- %s", __func__);164 return BEFS_OK;165 166 error:167 befs_debug(sb, "<--- %s ERROR", __func__);168 return BEFS_ERR;169}170 171/**172 * befs_bt_read_node - read in btree node and convert to cpu byteorder173 * @sb: Filesystem superblock174 * @ds: Datastream to read from175 * @node: Buffer in which to place the btree node176 * @node_off: Starting offset (in bytes) of the node in @ds177 *178 * Calls befs_read_datastream to read in the indicated btree node and179 * makes sure its header fields are in cpu byteorder, byteswapping if180 * necessary.181 * Note: node->bh must be NULL when this function is called the first time.182 * Don't forget brelse(node->bh) after last call.183 *184 * On success, returns BEFS_OK and *@node contains the btree node that185 * starts at @node_off, with the node->head fields in cpu byte order.186 *187 * On failure, BEFS_ERR is returned.188 */189 190static int191befs_bt_read_node(struct super_block *sb, const befs_data_stream *ds,192 struct befs_btree_node *node, befs_off_t node_off)193{194 uint off = 0;195 196 befs_debug(sb, "---> %s", __func__);197 198 if (node->bh)199 brelse(node->bh);200 201 node->bh = befs_read_datastream(sb, ds, node_off, &off);202 if (!node->bh) {203 befs_error(sb, "%s failed to read "204 "node at %llu", __func__, node_off);205 befs_debug(sb, "<--- %s ERROR", __func__);206 207 return BEFS_ERR;208 }209 node->od_node =210 (befs_btree_nodehead *) ((void *) node->bh->b_data + off);211 212 befs_dump_index_node(sb, node->od_node);213 214 node->head.left = fs64_to_cpu(sb, node->od_node->left);215 node->head.right = fs64_to_cpu(sb, node->od_node->right);216 node->head.overflow = fs64_to_cpu(sb, node->od_node->overflow);217 node->head.all_key_count =218 fs16_to_cpu(sb, node->od_node->all_key_count);219 node->head.all_key_length =220 fs16_to_cpu(sb, node->od_node->all_key_length);221 222 befs_debug(sb, "<--- %s", __func__);223 return BEFS_OK;224}225 226/**227 * befs_btree_find - Find a key in a befs B+tree228 * @sb: Filesystem superblock229 * @ds: Datastream containing btree230 * @key: Key string to lookup in btree231 * @value: Value stored with @key232 *233 * On success, returns BEFS_OK and sets *@value to the value stored234 * with @key (usually the disk block number of an inode).235 *236 * On failure, returns BEFS_ERR or BEFS_BT_NOT_FOUND.237 *238 * Algorithm:239 * Read the superblock and rootnode of the b+tree.240 * Drill down through the interior nodes using befs_find_key().241 * Once at the correct leaf node, use befs_find_key() again to get the242 * actual value stored with the key.243 */244int245befs_btree_find(struct super_block *sb, const befs_data_stream *ds,246 const char *key, befs_off_t * value)247{248 struct befs_btree_node *this_node;249 befs_btree_super bt_super;250 befs_off_t node_off;251 int res;252 253 befs_debug(sb, "---> %s Key: %s", __func__, key);254 255 if (befs_bt_read_super(sb, ds, &bt_super) != BEFS_OK) {256 befs_error(sb,257 "befs_btree_find() failed to read index superblock");258 goto error;259 }260 261 this_node = kmalloc(sizeof(struct befs_btree_node),262 GFP_NOFS);263 if (!this_node) {264 befs_error(sb, "befs_btree_find() failed to allocate %zu "265 "bytes of memory", sizeof(struct befs_btree_node));266 goto error;267 }268 269 this_node->bh = NULL;270 271 /* read in root node */272 node_off = bt_super.root_node_ptr;273 if (befs_bt_read_node(sb, ds, this_node, node_off) != BEFS_OK) {274 befs_error(sb, "befs_btree_find() failed to read "275 "node at %llu", node_off);276 goto error_alloc;277 }278 279 while (!befs_leafnode(this_node)) {280 res = befs_find_key(sb, this_node, key, &node_off);281 /* if no key set, try the overflow node */282 if (res == BEFS_BT_OVERFLOW)283 node_off = this_node->head.overflow;284 if (befs_bt_read_node(sb, ds, this_node, node_off) != BEFS_OK) {285 befs_error(sb, "befs_btree_find() failed to read "286 "node at %llu", node_off);287 goto error_alloc;288 }289 }290 291 /* at a leaf node now, check if it is correct */292 res = befs_find_key(sb, this_node, key, value);293 294 brelse(this_node->bh);295 kfree(this_node);296 297 if (res != BEFS_BT_MATCH) {298 befs_error(sb, "<--- %s Key %s not found", __func__, key);299 befs_debug(sb, "<--- %s ERROR", __func__);300 *value = 0;301 return BEFS_BT_NOT_FOUND;302 }303 befs_debug(sb, "<--- %s Found key %s, value %llu", __func__,304 key, *value);305 return BEFS_OK;306 307 error_alloc:308 kfree(this_node);309 error:310 *value = 0;311 befs_debug(sb, "<--- %s ERROR", __func__);312 return BEFS_ERR;313}314 315/**316 * befs_find_key - Search for a key within a node317 * @sb: Filesystem superblock318 * @node: Node to find the key within319 * @findkey: Keystring to search for320 * @value: If key is found, the value stored with the key is put here321 *322 * Finds exact match if one exists, and returns BEFS_BT_MATCH.323 * If there is no match and node's value array is too small for key, return324 * BEFS_BT_OVERFLOW.325 * If no match and node should countain this key, return BEFS_BT_NOT_FOUND.326 *327 * Uses binary search instead of a linear.328 */329static int330befs_find_key(struct super_block *sb, struct befs_btree_node *node,331 const char *findkey, befs_off_t * value)332{333 int first, last, mid;334 int eq;335 u16 keylen;336 int findkey_len;337 char *thiskey;338 fs64 *valarray;339 340 befs_debug(sb, "---> %s %s", __func__, findkey);341 342 findkey_len = strlen(findkey);343 344 /* if node can not contain key, just skip this node */345 last = node->head.all_key_count - 1;346 thiskey = befs_bt_get_key(sb, node, last, &keylen);347 348 eq = befs_compare_strings(thiskey, keylen, findkey, findkey_len);349 if (eq < 0) {350 befs_debug(sb, "<--- node can't contain %s", findkey);351 return BEFS_BT_OVERFLOW;352 }353 354 valarray = befs_bt_valarray(node);355 356 /* simple binary search */357 first = 0;358 mid = 0;359 while (last >= first) {360 mid = (last + first) / 2;361 befs_debug(sb, "first: %d, last: %d, mid: %d", first, last,362 mid);363 thiskey = befs_bt_get_key(sb, node, mid, &keylen);364 eq = befs_compare_strings(thiskey, keylen, findkey,365 findkey_len);366 367 if (eq == 0) {368 befs_debug(sb, "<--- %s found %s at %d",369 __func__, thiskey, mid);370 371 *value = fs64_to_cpu(sb, valarray[mid]);372 return BEFS_BT_MATCH;373 }374 if (eq > 0)375 last = mid - 1;376 else377 first = mid + 1;378 }379 380 /* return an existing value so caller can arrive to a leaf node */381 if (eq < 0)382 *value = fs64_to_cpu(sb, valarray[mid + 1]);383 else384 *value = fs64_to_cpu(sb, valarray[mid]);385 befs_error(sb, "<--- %s %s not found", __func__, findkey);386 befs_debug(sb, "<--- %s ERROR", __func__);387 return BEFS_BT_NOT_FOUND;388}389 390/**391 * befs_btree_read - Traverse leafnodes of a btree392 * @sb: Filesystem superblock393 * @ds: Datastream containing btree394 * @key_no: Key number (alphabetical order) of key to read395 * @bufsize: Size of the buffer to return key in396 * @keybuf: Pointer to a buffer to put the key in397 * @keysize: Length of the returned key398 * @value: Value stored with the returned key399 *400 * Here's how it works: Key_no is the index of the key/value pair to401 * return in keybuf/value.402 * Bufsize is the size of keybuf (BEFS_NAME_LEN+1 is a good size). Keysize is403 * the number of characters in the key (just a convenience).404 *405 * Algorithm:406 * Get the first leafnode of the tree. See if the requested key is in that407 * node. If not, follow the node->right link to the next leafnode. Repeat408 * until the (key_no)th key is found or the tree is out of keys.409 */410int411befs_btree_read(struct super_block *sb, const befs_data_stream *ds,412 loff_t key_no, size_t bufsize, char *keybuf, size_t * keysize,413 befs_off_t * value)414{415 struct befs_btree_node *this_node;416 befs_btree_super bt_super;417 befs_off_t node_off;418 int cur_key;419 fs64 *valarray;420 char *keystart;421 u16 keylen;422 int res;423 424 uint key_sum = 0;425 426 befs_debug(sb, "---> %s", __func__);427 428 if (befs_bt_read_super(sb, ds, &bt_super) != BEFS_OK) {429 befs_error(sb,430 "befs_btree_read() failed to read index superblock");431 goto error;432 }433 434 this_node = kmalloc(sizeof(struct befs_btree_node), GFP_NOFS);435 if (this_node == NULL) {436 befs_error(sb, "befs_btree_read() failed to allocate %zu "437 "bytes of memory", sizeof(struct befs_btree_node));438 goto error;439 }440 441 node_off = bt_super.root_node_ptr;442 this_node->bh = NULL;443 444 /* seeks down to first leafnode, reads it into this_node */445 res = befs_btree_seekleaf(sb, ds, &bt_super, this_node, &node_off);446 if (res == BEFS_BT_EMPTY) {447 brelse(this_node->bh);448 kfree(this_node);449 *value = 0;450 *keysize = 0;451 befs_debug(sb, "<--- %s Tree is EMPTY", __func__);452 return BEFS_BT_EMPTY;453 } else if (res == BEFS_ERR) {454 goto error_alloc;455 }456 457 /* find the leaf node containing the key_no key */458 459 while (key_sum + this_node->head.all_key_count <= key_no) {460 461 /* no more nodes to look in: key_no is too large */462 if (this_node->head.right == BEFS_BT_INVAL) {463 *keysize = 0;464 *value = 0;465 befs_debug(sb,466 "<--- %s END of keys at %llu", __func__,467 (unsigned long long)468 key_sum + this_node->head.all_key_count);469 brelse(this_node->bh);470 kfree(this_node);471 return BEFS_BT_END;472 }473 474 key_sum += this_node->head.all_key_count;475 node_off = this_node->head.right;476 477 if (befs_bt_read_node(sb, ds, this_node, node_off) != BEFS_OK) {478 befs_error(sb, "%s failed to read node at %llu",479 __func__, (unsigned long long)node_off);480 goto error_alloc;481 }482 }483 484 /* how many keys into this_node is key_no */485 cur_key = key_no - key_sum;486 487 /* get pointers to datastructures within the node body */488 valarray = befs_bt_valarray(this_node);489 490 keystart = befs_bt_get_key(sb, this_node, cur_key, &keylen);491 492 befs_debug(sb, "Read [%llu,%d]: keysize %d",493 (long long unsigned int)node_off, (int)cur_key,494 (int)keylen);495 496 if (bufsize < keylen + 1) {497 befs_error(sb, "%s keybuf too small (%zu) "498 "for key of size %d", __func__, bufsize, keylen);499 brelse(this_node->bh);500 goto error_alloc;501 }502 503 strscpy(keybuf, keystart, keylen + 1);504 *value = fs64_to_cpu(sb, valarray[cur_key]);505 *keysize = keylen;506 507 befs_debug(sb, "Read [%llu,%d]: Key \"%.*s\", Value %llu", node_off,508 cur_key, keylen, keybuf, *value);509 510 brelse(this_node->bh);511 kfree(this_node);512 513 befs_debug(sb, "<--- %s", __func__);514 515 return BEFS_OK;516 517 error_alloc:518 kfree(this_node);519 520 error:521 *keysize = 0;522 *value = 0;523 befs_debug(sb, "<--- %s ERROR", __func__);524 return BEFS_ERR;525}526 527/**528 * befs_btree_seekleaf - Find the first leafnode in the btree529 * @sb: Filesystem superblock530 * @ds: Datastream containing btree531 * @bt_super: Pointer to the superblock of the btree532 * @this_node: Buffer to return the leafnode in533 * @node_off: Pointer to offset of current node within datastream. Modified534 * by the function.535 *536 * Helper function for btree traverse. Moves the current position to the537 * start of the first leaf node.538 *539 * Also checks for an empty tree. If there are no keys, returns BEFS_BT_EMPTY.540 */541static int542befs_btree_seekleaf(struct super_block *sb, const befs_data_stream *ds,543 befs_btree_super *bt_super,544 struct befs_btree_node *this_node,545 befs_off_t * node_off)546{547 548 befs_debug(sb, "---> %s", __func__);549 550 if (befs_bt_read_node(sb, ds, this_node, *node_off) != BEFS_OK) {551 befs_error(sb, "%s failed to read "552 "node at %llu", __func__, *node_off);553 goto error;554 }555 befs_debug(sb, "Seekleaf to root node %llu", *node_off);556 557 if (this_node->head.all_key_count == 0 && befs_leafnode(this_node)) {558 befs_debug(sb, "<--- %s Tree is EMPTY", __func__);559 return BEFS_BT_EMPTY;560 }561 562 while (!befs_leafnode(this_node)) {563 564 if (this_node->head.all_key_count == 0) {565 befs_debug(sb, "%s encountered "566 "an empty interior node: %llu. Using Overflow "567 "node: %llu", __func__, *node_off,568 this_node->head.overflow);569 *node_off = this_node->head.overflow;570 } else {571 fs64 *valarray = befs_bt_valarray(this_node);572 *node_off = fs64_to_cpu(sb, valarray[0]);573 }574 if (befs_bt_read_node(sb, ds, this_node, *node_off) != BEFS_OK) {575 befs_error(sb, "%s failed to read "576 "node at %llu", __func__, *node_off);577 goto error;578 }579 580 befs_debug(sb, "Seekleaf to child node %llu", *node_off);581 }582 befs_debug(sb, "Node %llu is a leaf node", *node_off);583 584 return BEFS_OK;585 586 error:587 befs_debug(sb, "<--- %s ERROR", __func__);588 return BEFS_ERR;589}590 591/**592 * befs_leafnode - Determine if the btree node is a leaf node or an593 * interior node594 * @node: Pointer to node structure to test595 *596 * Return 1 if leaf, 0 if interior597 */598static int599befs_leafnode(struct befs_btree_node *node)600{601 /* all interior nodes (and only interior nodes) have an overflow node */602 if (node->head.overflow == BEFS_BT_INVAL)603 return 1;604 else605 return 0;606}607 608/**609 * befs_bt_keylen_index - Finds start of keylen index in a node610 * @node: Pointer to the node structure to find the keylen index within611 *612 * Returns a pointer to the start of the key length index array613 * of the B+tree node *@node614 *615 * "The length of all the keys in the node is added to the size of the616 * header and then rounded up to a multiple of four to get the beginning617 * of the key length index" (p.88, practical filesystem design).618 *619 * Except that rounding up to 8 works, and rounding up to 4 doesn't.620 */621static fs16 *622befs_bt_keylen_index(struct befs_btree_node *node)623{624 const int keylen_align = 8;625 unsigned long int off =626 (sizeof (befs_btree_nodehead) + node->head.all_key_length);627 ulong tmp = off % keylen_align;628 629 if (tmp)630 off += keylen_align - tmp;631 632 return (fs16 *) ((void *) node->od_node + off);633}634 635/**636 * befs_bt_valarray - Finds the start of value array in a node637 * @node: Pointer to the node structure to find the value array within638 *639 * Returns a pointer to the start of the value array640 * of the node pointed to by the node header641 */642static fs64 *643befs_bt_valarray(struct befs_btree_node *node)644{645 void *keylen_index_start = (void *) befs_bt_keylen_index(node);646 size_t keylen_index_size = node->head.all_key_count * sizeof (fs16);647 648 return (fs64 *) (keylen_index_start + keylen_index_size);649}650 651/**652 * befs_bt_keydata - Finds start of keydata array in a node653 * @node: Pointer to the node structure to find the keydata array within654 *655 * Returns a pointer to the start of the keydata array656 * of the node pointed to by the node header657 */658static char *659befs_bt_keydata(struct befs_btree_node *node)660{661 return (char *) ((void *) node->od_node + sizeof (befs_btree_nodehead));662}663 664/**665 * befs_bt_get_key - returns a pointer to the start of a key666 * @sb: filesystem superblock667 * @node: node in which to look for the key668 * @index: the index of the key to get669 * @keylen: modified to be the length of the key at @index670 *671 * Returns a valid pointer into @node on success.672 * Returns NULL on failure (bad input) and sets *@keylen = 0673 */674static char *675befs_bt_get_key(struct super_block *sb, struct befs_btree_node *node,676 int index, u16 * keylen)677{678 int prev_key_end;679 char *keystart;680 fs16 *keylen_index;681 682 if (index < 0 || index > node->head.all_key_count) {683 *keylen = 0;684 return NULL;685 }686 687 keystart = befs_bt_keydata(node);688 keylen_index = befs_bt_keylen_index(node);689 690 if (index == 0)691 prev_key_end = 0;692 else693 prev_key_end = fs16_to_cpu(sb, keylen_index[index - 1]);694 695 *keylen = fs16_to_cpu(sb, keylen_index[index]) - prev_key_end;696 697 return keystart + prev_key_end;698}699 700/**701 * befs_compare_strings - compare two strings702 * @key1: pointer to the first key to be compared703 * @keylen1: length in bytes of key1704 * @key2: pointer to the second key to be compared705 * @keylen2: length in bytes of key2706 *707 * Returns 0 if @key1 and @key2 are equal.708 * Returns >0 if @key1 is greater.709 * Returns <0 if @key2 is greater.710 */711static int712befs_compare_strings(const void *key1, int keylen1,713 const void *key2, int keylen2)714{715 int len = min_t(int, keylen1, keylen2);716 int result = strncmp(key1, key2, len);717 if (result == 0)718 result = keylen1 - keylen2;719 return result;720}721 722/* These will be used for non-string keyed btrees */723#if 0724static int725btree_compare_int32(cont void *key1, int keylen1, const void *key2, int keylen2)726{727 return *(int32_t *) key1 - *(int32_t *) key2;728}729 730static int731btree_compare_uint32(cont void *key1, int keylen1,732 const void *key2, int keylen2)733{734 if (*(u_int32_t *) key1 == *(u_int32_t *) key2)735 return 0;736 else if (*(u_int32_t *) key1 > *(u_int32_t *) key2)737 return 1;738 739 return -1;740}741static int742btree_compare_int64(cont void *key1, int keylen1, const void *key2, int keylen2)743{744 if (*(int64_t *) key1 == *(int64_t *) key2)745 return 0;746 else if (*(int64_t *) key1 > *(int64_t *) key2)747 return 1;748 749 return -1;750}751 752static int753btree_compare_uint64(cont void *key1, int keylen1,754 const void *key2, int keylen2)755{756 if (*(u_int64_t *) key1 == *(u_int64_t *) key2)757 return 0;758 else if (*(u_int64_t *) key1 > *(u_int64_t *) key2)759 return 1;760 761 return -1;762}763 764static int765btree_compare_float(cont void *key1, int keylen1, const void *key2, int keylen2)766{767 float result = *(float *) key1 - *(float *) key2;768 if (result == 0.0f)769 return 0;770 771 return (result < 0.0f) ? -1 : 1;772}773 774static int775btree_compare_double(cont void *key1, int keylen1,776 const void *key2, int keylen2)777{778 double result = *(double *) key1 - *(double *) key2;779 if (result == 0.0)780 return 0;781 782 return (result < 0.0) ? -1 : 1;783}784#endif //0785