--- /dev/null
+/*
+ * linux/fs/befs/btree.c
+ *
+ * Copyright (C) 2001-2002 Will Dyson <will_dyson@pobox.com>
+ *
+ * Licensed under the GNU GPL. See the file COPYING for details.
+ *
+ * 2002-02-05: Sergey S. Kostyliov added binary search within
+ * btree nodes.
+ *
+ * Many thanks to:
+ *
+ * Dominic Giampaolo, author of "Practical File System
+ * Design with the Be File System", for such a helpful book.
+ *
+ * Marcus J. Ranum, author of the b+tree package in
+ * comp.sources.misc volume 10. This code is not copied from that
+ * work, but it is partially based on it.
+ *
+ * Makoto Kato, author of the original BeFS for linux filesystem
+ * driver.
+ */
+
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/mm.h>
+#include <linux/buffer_head.h>
+
+#include "befs.h"
+#include "btree.h"
+#include "datastream.h"
+
+/*
+ * The btree functions in this file are built on top of the
+ * datastream.c interface, which is in turn built on top of the
+ * io.c interface.
+ */
+
+/* Befs B+tree structure:
+ *
+ * The first thing in the tree is the tree superblock. It tells you
+ * all kinds of useful things about the tree, like where the rootnode
+ * is located, and the size of the nodes (always 1024 with current version
+ * of BeOS).
+ *
+ * The rest of the tree consists of a series of nodes. Nodes contain a header
+ * (struct befs_btree_nodehead), the packed key data, an array of shorts
+ * containing the ending offsets for each of the keys, and an array of
+ * befs_off_t values. In interior nodes, the keys are the ending keys for
+ * the childnode they point to, and the values are offsets into the
+ * datastream containing the tree.
+ */
+
+/* Note:
+ *
+ * The book states 2 confusing things about befs b+trees. First,
+ * it states that the overflow field of node headers is used by internal nodes
+ * to point to another node that "effectively continues this one". Here is what
+ * I believe that means. Each key in internal nodes points to another node that
+ * contains key values less than itself. Inspection reveals that the last key
+ * in the internal node is not the last key in the index. Keys that are
+ * greater than the last key in the internal node go into the overflow node.
+ * I imagine there is a performance reason for this.
+ *
+ * Second, it states that the header of a btree node is sufficient to
+ * distinguish internal nodes from leaf nodes. Without saying exactly how.
+ * After figuring out the first, it becomes obvious that internal nodes have
+ * overflow nodes and leafnodes do not.
+ */
+
+/*
+ * Currently, this code is only good for directory B+trees.
+ * In order to be used for other BFS indexes, it needs to be extended to handle
+ * duplicate keys and non-string keytypes (int32, int64, float, double).
+ */
+
+/*
+ * In memory structure of each btree node
+ */
+struct befs_btree_node {
+ befs_host_btree_nodehead head; /* head of node converted to cpu byteorder */
+ struct buffer_head *bh;
+ befs_btree_nodehead *od_node; /* on disk node */
+};
+
+/* local constants */
+static const befs_off_t befs_bt_inval = 0xffffffffffffffffULL;
+
+/* local functions */
+static int befs_btree_seekleaf(struct super_block *sb, befs_data_stream * ds,
+ befs_btree_super * bt_super,
+ struct befs_btree_node *this_node,
+ befs_off_t * node_off);
+
+static int befs_bt_read_super(struct super_block *sb, befs_data_stream * ds,
+ befs_btree_super * sup);
+
+static int befs_bt_read_node(struct super_block *sb, befs_data_stream * ds,
+ struct befs_btree_node *node,
+ befs_off_t node_off);
+
+static int befs_leafnode(struct befs_btree_node *node);
+
+static fs16 *befs_bt_keylen_index(struct befs_btree_node *node);
+
+static fs64 *befs_bt_valarray(struct befs_btree_node *node);
+
+static char *befs_bt_keydata(struct befs_btree_node *node);
+
+static int befs_find_key(struct super_block *sb,
+ struct befs_btree_node *node,
+ const char *findkey, befs_off_t * value);
+
+static char *befs_bt_get_key(struct super_block *sb,
+ struct befs_btree_node *node,
+ int index, u16 * keylen);
+
+static int befs_compare_strings(const void *key1, int keylen1,
+ const void *key2, int keylen2);
+
+/**
+ * befs_bt_read_super - read in btree superblock convert to cpu byteorder
+ * @sb: Filesystem superblock
+ * @ds: Datastream to read from
+ * @sup: Buffer in which to place the btree superblock
+ *
+ * Calls befs_read_datastream to read in the btree superblock and
+ * makes sure it is in cpu byteorder, byteswapping if necessary.
+ *
+ * On success, returns BEFS_OK and *@sup contains the btree superblock,
+ * in cpu byte order.
+ *
+ * On failure, BEFS_ERR is returned.
+ */
+static int
+befs_bt_read_super(struct super_block *sb, befs_data_stream * ds,
+ befs_btree_super * sup)
+{
+ struct buffer_head *bh = NULL;
+ befs_disk_btree_super *od_sup = NULL;
+
+ befs_debug(sb, "---> %s", __func__);
+
+ bh = befs_read_datastream(sb, ds, 0, NULL);
+
+ if (!bh) {
+ befs_error(sb, "Couldn't read index header.");
+ goto error;
+ }
+ od_sup = (befs_disk_btree_super *) bh->b_data;
+ befs_dump_index_entry(sb, od_sup);
+
+ sup->magic = fs32_to_cpu(sb, od_sup->magic);
+ sup->node_size = fs32_to_cpu(sb, od_sup->node_size);
+ sup->max_depth = fs32_to_cpu(sb, od_sup->max_depth);
+ sup->data_type = fs32_to_cpu(sb, od_sup->data_type);
+ sup->root_node_ptr = fs64_to_cpu(sb, od_sup->root_node_ptr);
+ sup->free_node_ptr = fs64_to_cpu(sb, od_sup->free_node_ptr);
+ sup->max_size = fs64_to_cpu(sb, od_sup->max_size);
+
+ brelse(bh);
+ if (sup->magic != BEFS_BTREE_MAGIC) {
+ befs_error(sb, "Index header has bad magic.");
+ goto error;
+ }
+
+ befs_debug(sb, "<--- %s", __func__);
+ return BEFS_OK;
+
+ error:
+ befs_debug(sb, "<--- %s ERROR", __func__);
+ return BEFS_ERR;
+}
+
+/**
+ * befs_bt_read_node - read in btree node and convert to cpu byteorder
+ * @sb: Filesystem superblock
+ * @ds: Datastream to read from
+ * @node: Buffer in which to place the btree node
+ * @node_off: Starting offset (in bytes) of the node in @ds
+ *
+ * Calls befs_read_datastream to read in the indicated btree node and
+ * makes sure its header fields are in cpu byteorder, byteswapping if
+ * necessary.
+ * Note: node->bh must be NULL when this function called first
+ * time. Don't forget brelse(node->bh) after last call.
+ *
+ * On success, returns BEFS_OK and *@node contains the btree node that
+ * starts at @node_off, with the node->head fields in cpu byte order.
+ *
+ * On failure, BEFS_ERR is returned.
+ */
+
+static int
+befs_bt_read_node(struct super_block *sb, befs_data_stream * ds,
+ struct befs_btree_node *node, befs_off_t node_off)
+{
+ uint off = 0;
+
+ befs_debug(sb, "---> %s", __func__);
+
+ if (node->bh)
+ brelse(node->bh);
+
+ node->bh = befs_read_datastream(sb, ds, node_off, &off);
+ if (!node->bh) {
+ befs_error(sb, "%s failed to read "
+ "node at %llu", __func__, node_off);
+ befs_debug(sb, "<--- %s ERROR", __func__);
+
+ return BEFS_ERR;
+ }
+ node->od_node =
+ (befs_btree_nodehead *) ((void *) node->bh->b_data + off);
+
+ befs_dump_index_node(sb, node->od_node);
+
+ node->head.left = fs64_to_cpu(sb, node->od_node->left);
+ node->head.right = fs64_to_cpu(sb, node->od_node->right);
+ node->head.overflow = fs64_to_cpu(sb, node->od_node->overflow);
+ node->head.all_key_count =
+ fs16_to_cpu(sb, node->od_node->all_key_count);
+ node->head.all_key_length =
+ fs16_to_cpu(sb, node->od_node->all_key_length);
+
+ befs_debug(sb, "<--- %s", __func__);
+ return BEFS_OK;
+}
+
+/**
+ * befs_btree_find - Find a key in a befs B+tree
+ * @sb: Filesystem superblock
+ * @ds: Datastream containing btree
+ * @key: Key string to lookup in btree
+ * @value: Value stored with @key
+ *
+ * On success, returns BEFS_OK and sets *@value to the value stored
+ * with @key (usually the disk block number of an inode).
+ *
+ * On failure, returns BEFS_ERR or BEFS_BT_NOT_FOUND.
+ *
+ * Algorithm:
+ * Read the superblock and rootnode of the b+tree.
+ * Drill down through the interior nodes using befs_find_key().
+ * Once at the correct leaf node, use befs_find_key() again to get the
+ * actuall value stored with the key.
+ */
+int
+befs_btree_find(struct super_block *sb, befs_data_stream * ds,
+ const char *key, befs_off_t * value)
+{
+ struct befs_btree_node *this_node = NULL;
+ befs_btree_super bt_super;
+ befs_off_t node_off;
+ int res;
+
+ befs_debug(sb, "---> %s Key: %s", __func__, key);
+
+ if (befs_bt_read_super(sb, ds, &bt_super) != BEFS_OK) {
+ befs_error(sb,
+ "befs_btree_find() failed to read index superblock");
+ goto error;
+ }
+
+ this_node = kmalloc(sizeof(struct befs_btree_node),
+ GFP_NOFS);
+ if (!this_node) {
+ befs_error(sb, "befs_btree_find() failed to allocate %zu "
+ "bytes of memory", sizeof(struct befs_btree_node));
+ goto error;
+ }
+
+ this_node->bh = NULL;
+
+ /* read in root node */
+ node_off = bt_super.root_node_ptr;
+ if (befs_bt_read_node(sb, ds, this_node, node_off) != BEFS_OK) {
+ befs_error(sb, "befs_btree_find() failed to read "
+ "node at %llu", node_off);
+ goto error_alloc;
+ }
+
+ while (!befs_leafnode(this_node)) {
+ res = befs_find_key(sb, this_node, key, &node_off);
+ if (res == BEFS_BT_NOT_FOUND)
+ node_off = this_node->head.overflow;
+ /* if no match, go to overflow node */
+ if (befs_bt_read_node(sb, ds, this_node, node_off) != BEFS_OK) {
+ befs_error(sb, "befs_btree_find() failed to read "
+ "node at %llu", node_off);
+ goto error_alloc;
+ }
+ }
+
+ /* at the correct leaf node now */
+
+ res = befs_find_key(sb, this_node, key, value);
+
+ brelse(this_node->bh);
+ kfree(this_node);
+
+ if (res != BEFS_BT_MATCH) {
+ befs_debug(sb, "<--- %s Key %s not found", __func__, key);
+ *value = 0;
+ return BEFS_BT_NOT_FOUND;
+ }
+ befs_debug(sb, "<--- %s Found key %s, value %llu", __func__,
+ key, *value);
+ return BEFS_OK;
+
+ error_alloc:
+ kfree(this_node);
+ error:
+ *value = 0;
+ befs_debug(sb, "<--- %s ERROR", __func__);
+ return BEFS_ERR;
+}
+
+/**
+ * befs_find_key - Search for a key within a node
+ * @sb: Filesystem superblock
+ * @node: Node to find the key within
+ * @findkey: Keystring to search for
+ * @value: If key is found, the value stored with the key is put here
+ *
+ * finds exact match if one exists, and returns BEFS_BT_MATCH
+ * If no exact match, finds first key in node that is greater
+ * (alphabetically) than the search key and returns BEFS_BT_PARMATCH
+ * (for partial match, I guess). Can you think of something better to
+ * call it?
+ *
+ * If no key was a match or greater than the search key, return
+ * BEFS_BT_NOT_FOUND.
+ *
+ * Use binary search instead of a linear.
+ */
+static int
+befs_find_key(struct super_block *sb, struct befs_btree_node *node,
+ const char *findkey, befs_off_t * value)
+{
+ int first, last, mid;
+ int eq;
+ u16 keylen;
+ int findkey_len;
+ char *thiskey;
+ fs64 *valarray;
+
+ befs_debug(sb, "---> %s %s", __func__, findkey);
+
+ *value = 0;
+
+ findkey_len = strlen(findkey);
+
+ /* if node can not contain key, just skeep this node */
+ last = node->head.all_key_count - 1;
+ thiskey = befs_bt_get_key(sb, node, last, &keylen);
+
+ eq = befs_compare_strings(thiskey, keylen, findkey, findkey_len);
+ if (eq < 0) {
+ befs_debug(sb, "<--- %s %s not found", __func__, findkey);
+ return BEFS_BT_NOT_FOUND;
+ }
+
+ valarray = befs_bt_valarray(node);
+
+ /* simple binary search */
+ first = 0;
+ mid = 0;
+ while (last >= first) {
+ mid = (last + first) / 2;
+ befs_debug(sb, "first: %d, last: %d, mid: %d", first, last,
+ mid);
+ thiskey = befs_bt_get_key(sb, node, mid, &keylen);
+ eq = befs_compare_strings(thiskey, keylen, findkey,
+ findkey_len);
+
+ if (eq == 0) {
+ befs_debug(sb, "<--- %s found %s at %d",
+ __func__, thiskey, mid);
+
+ *value = fs64_to_cpu(sb, valarray[mid]);
+ return BEFS_BT_MATCH;
+ }
+ if (eq > 0)
+ last = mid - 1;
+ else
+ first = mid + 1;
+ }
+ if (eq < 0)
+ *value = fs64_to_cpu(sb, valarray[mid + 1]);
+ else
+ *value = fs64_to_cpu(sb, valarray[mid]);
+ befs_debug(sb, "<--- %s found %s at %d", __func__, thiskey, mid);
+ return BEFS_BT_PARMATCH;
+}
+
+/**
+ * befs_btree_read - Traverse leafnodes of a btree
+ * @sb: Filesystem superblock
+ * @ds: Datastream containing btree
+ * @key_no: Key number (alphabetical order) of key to read
+ * @bufsize: Size of the buffer to return key in
+ * @keybuf: Pointer to a buffer to put the key in
+ * @keysize: Length of the returned key
+ * @value: Value stored with the returned key
+ *
+ * Heres how it works: Key_no is the index of the key/value pair to
+ * return in keybuf/value.
+ * Bufsize is the size of keybuf (BEFS_NAME_LEN+1 is a good size). Keysize is
+ * the number of characters in the key (just a convenience).
+ *
+ * Algorithm:
+ * Get the first leafnode of the tree. See if the requested key is in that
+ * node. If not, follow the node->right link to the next leafnode. Repeat
+ * until the (key_no)th key is found or the tree is out of keys.
+ */
+int
+befs_btree_read(struct super_block *sb, befs_data_stream * ds,
+ loff_t key_no, size_t bufsize, char *keybuf, size_t * keysize,
+ befs_off_t * value)
+{
+ struct befs_btree_node *this_node;
+ befs_btree_super bt_super;
+ befs_off_t node_off = 0;
+ int cur_key;
+ fs64 *valarray;
+ char *keystart;
+ u16 keylen;
+ int res;
+
+ uint key_sum = 0;
+
+ befs_debug(sb, "---> %s", __func__);
+
+ if (befs_bt_read_super(sb, ds, &bt_super) != BEFS_OK) {
+ befs_error(sb,
+ "befs_btree_read() failed to read index superblock");
+ goto error;
+ }
+
+ this_node = kmalloc(sizeof(struct befs_btree_node), GFP_NOFS);
+ if (this_node == NULL) {
+ befs_error(sb, "befs_btree_read() failed to allocate %zu "
+ "bytes of memory", sizeof(struct befs_btree_node));
+ goto error;
+ }
+
+ node_off = bt_super.root_node_ptr;
+ this_node->bh = NULL;
+
+ /* seeks down to first leafnode, reads it into this_node */
+ res = befs_btree_seekleaf(sb, ds, &bt_super, this_node, &node_off);
+ if (res == BEFS_BT_EMPTY) {
+ brelse(this_node->bh);
+ kfree(this_node);
+ *value = 0;
+ *keysize = 0;
+ befs_debug(sb, "<--- %s Tree is EMPTY", __func__);
+ return BEFS_BT_EMPTY;
+ } else if (res == BEFS_ERR) {
+ goto error_alloc;
+ }
+
+ /* find the leaf node containing the key_no key */
+
+ while (key_sum + this_node->head.all_key_count <= key_no) {
+
+ /* no more nodes to look in: key_no is too large */
+ if (this_node->head.right == befs_bt_inval) {
+ *keysize = 0;
+ *value = 0;
+ befs_debug(sb,
+ "<--- %s END of keys at %llu", __func__,
+ (unsigned long long)
+ key_sum + this_node->head.all_key_count);
+ brelse(this_node->bh);
+ kfree(this_node);
+ return BEFS_BT_END;
+ }
+
+ key_sum += this_node->head.all_key_count;
+ node_off = this_node->head.right;
+
+ if (befs_bt_read_node(sb, ds, this_node, node_off) != BEFS_OK) {
+ befs_error(sb, "%s failed to read node at %llu",
+ __func__, (unsigned long long)node_off);
+ goto error_alloc;
+ }
+ }
+
+ /* how many keys into this_node is key_no */
+ cur_key = key_no - key_sum;
+
+ /* get pointers to datastructures within the node body */
+ valarray = befs_bt_valarray(this_node);
+
+ keystart = befs_bt_get_key(sb, this_node, cur_key, &keylen);
+
+ befs_debug(sb, "Read [%llu,%d]: keysize %d",
+ (long long unsigned int)node_off, (int)cur_key,
+ (int)keylen);
+
+ if (bufsize < keylen + 1) {
+ befs_error(sb, "%s keybuf too small (%zu) "
+ "for key of size %d", __func__, bufsize, keylen);
+ brelse(this_node->bh);
+ goto error_alloc;
+ }
+
+ strlcpy(keybuf, keystart, keylen + 1);
+ *value = fs64_to_cpu(sb, valarray[cur_key]);
+ *keysize = keylen;
+
+ befs_debug(sb, "Read [%llu,%d]: Key \"%.*s\", Value %llu", node_off,
+ cur_key, keylen, keybuf, *value);
+
+ brelse(this_node->bh);
+ kfree(this_node);
+
+ befs_debug(sb, "<--- %s", __func__);
+
+ return BEFS_OK;
+
+ error_alloc:
+ kfree(this_node);
+
+ error:
+ *keysize = 0;
+ *value = 0;
+ befs_debug(sb, "<--- %s ERROR", __func__);
+ return BEFS_ERR;
+}
+
+/**
+ * befs_btree_seekleaf - Find the first leafnode in the btree
+ * @sb: Filesystem superblock
+ * @ds: Datastream containing btree
+ * @bt_super: Pointer to the superblock of the btree
+ * @this_node: Buffer to return the leafnode in
+ * @node_off: Pointer to offset of current node within datastream. Modified
+ * by the function.
+ *
+ *
+ * Helper function for btree traverse. Moves the current position to the
+ * start of the first leaf node.
+ *
+ * Also checks for an empty tree. If there are no keys, returns BEFS_BT_EMPTY.
+ */
+static int
+befs_btree_seekleaf(struct super_block *sb, befs_data_stream * ds,
+ befs_btree_super *bt_super,
+ struct befs_btree_node *this_node,
+ befs_off_t * node_off)
+{
+
+ befs_debug(sb, "---> %s", __func__);
+
+ if (befs_bt_read_node(sb, ds, this_node, *node_off) != BEFS_OK) {
+ befs_error(sb, "%s failed to read "
+ "node at %llu", __func__, *node_off);
+ goto error;
+ }
+ befs_debug(sb, "Seekleaf to root node %llu", *node_off);
+
+ if (this_node->head.all_key_count == 0 && befs_leafnode(this_node)) {
+ befs_debug(sb, "<--- %s Tree is EMPTY", __func__);
+ return BEFS_BT_EMPTY;
+ }
+
+ while (!befs_leafnode(this_node)) {
+
+ if (this_node->head.all_key_count == 0) {
+ befs_debug(sb, "%s encountered "
+ "an empty interior node: %llu. Using Overflow "
+ "node: %llu", __func__, *node_off,
+ this_node->head.overflow);
+ *node_off = this_node->head.overflow;
+ } else {
+ fs64 *valarray = befs_bt_valarray(this_node);
+ *node_off = fs64_to_cpu(sb, valarray[0]);
+ }
+ if (befs_bt_read_node(sb, ds, this_node, *node_off) != BEFS_OK) {
+ befs_error(sb, "%s failed to read "
+ "node at %llu", __func__, *node_off);
+ goto error;
+ }
+
+ befs_debug(sb, "Seekleaf to child node %llu", *node_off);
+ }
+ befs_debug(sb, "Node %llu is a leaf node", *node_off);
+
+ return BEFS_OK;
+
+ error:
+ befs_debug(sb, "<--- %s ERROR", __func__);
+ return BEFS_ERR;
+}
+
+/**
+ * befs_leafnode - Determine if the btree node is a leaf node or an
+ * interior node
+ * @node: Pointer to node structure to test
+ *
+ * Return 1 if leaf, 0 if interior
+ */
+static int
+befs_leafnode(struct befs_btree_node *node)
+{
+ /* all interior nodes (and only interior nodes) have an overflow node */
+ if (node->head.overflow == befs_bt_inval)
+ return 1;
+ else
+ return 0;
+}
+
+/**
+ * befs_bt_keylen_index - Finds start of keylen index in a node
+ * @node: Pointer to the node structure to find the keylen index within
+ *
+ * Returns a pointer to the start of the key length index array
+ * of the B+tree node *@node
+ *
+ * "The length of all the keys in the node is added to the size of the
+ * header and then rounded up to a multiple of four to get the beginning
+ * of the key length index" (p.88, practical filesystem design).
+ *
+ * Except that rounding up to 8 works, and rounding up to 4 doesn't.
+ */
+static fs16 *
+befs_bt_keylen_index(struct befs_btree_node *node)
+{
+ const int keylen_align = 8;
+ unsigned long int off =
+ (sizeof (befs_btree_nodehead) + node->head.all_key_length);
+ ulong tmp = off % keylen_align;
+
+ if (tmp)
+ off += keylen_align - tmp;
+
+ return (fs16 *) ((void *) node->od_node + off);
+}
+
+/**
+ * befs_bt_valarray - Finds the start of value array in a node
+ * @node: Pointer to the node structure to find the value array within
+ *
+ * Returns a pointer to the start of the value array
+ * of the node pointed to by the node header
+ */
+static fs64 *
+befs_bt_valarray(struct befs_btree_node *node)
+{
+ void *keylen_index_start = (void *) befs_bt_keylen_index(node);
+ size_t keylen_index_size = node->head.all_key_count * sizeof (fs16);
+
+ return (fs64 *) (keylen_index_start + keylen_index_size);
+}
+
+/**
+ * befs_bt_keydata - Finds start of keydata array in a node
+ * @node: Pointer to the node structure to find the keydata array within
+ *
+ * Returns a pointer to the start of the keydata array
+ * of the node pointed to by the node header
+ */
+static char *
+befs_bt_keydata(struct befs_btree_node *node)
+{
+ return (char *) ((void *) node->od_node + sizeof (befs_btree_nodehead));
+}
+
+/**
+ * befs_bt_get_key - returns a pointer to the start of a key
+ * @sb: filesystem superblock
+ * @node: node in which to look for the key
+ * @index: the index of the key to get
+ * @keylen: modified to be the length of the key at @index
+ *
+ * Returns a valid pointer into @node on success.
+ * Returns NULL on failure (bad input) and sets *@keylen = 0
+ */
+static char *
+befs_bt_get_key(struct super_block *sb, struct befs_btree_node *node,
+ int index, u16 * keylen)
+{
+ int prev_key_end;
+ char *keystart;
+ fs16 *keylen_index;
+
+ if (index < 0 || index > node->head.all_key_count) {
+ *keylen = 0;
+ return NULL;
+ }
+
+ keystart = befs_bt_keydata(node);
+ keylen_index = befs_bt_keylen_index(node);
+
+ if (index == 0)
+ prev_key_end = 0;
+ else
+ prev_key_end = fs16_to_cpu(sb, keylen_index[index - 1]);
+
+ *keylen = fs16_to_cpu(sb, keylen_index[index]) - prev_key_end;
+
+ return keystart + prev_key_end;
+}
+
+/**
+ * befs_compare_strings - compare two strings
+ * @key1: pointer to the first key to be compared
+ * @keylen1: length in bytes of key1
+ * @key2: pointer to the second key to be compared
+ * @keylen2: length in bytes of key2
+ *
+ * Returns 0 if @key1 and @key2 are equal.
+ * Returns >0 if @key1 is greater.
+ * Returns <0 if @key2 is greater..
+ */
+static int
+befs_compare_strings(const void *key1, int keylen1,
+ const void *key2, int keylen2)
+{
+ int len = min_t(int, keylen1, keylen2);
+ int result = strncmp(key1, key2, len);
+ if (result == 0)
+ result = keylen1 - keylen2;
+ return result;
+}
+
+/* These will be used for non-string keyed btrees */
+#if 0
+static int
+btree_compare_int32(cont void *key1, int keylen1, const void *key2, int keylen2)
+{
+ return *(int32_t *) key1 - *(int32_t *) key2;
+}
+
+static int
+btree_compare_uint32(cont void *key1, int keylen1,
+ const void *key2, int keylen2)
+{
+ if (*(u_int32_t *) key1 == *(u_int32_t *) key2)
+ return 0;
+ else if (*(u_int32_t *) key1 > *(u_int32_t *) key2)
+ return 1;
+
+ return -1;
+}
+static int
+btree_compare_int64(cont void *key1, int keylen1, const void *key2, int keylen2)
+{
+ if (*(int64_t *) key1 == *(int64_t *) key2)
+ return 0;
+ else if (*(int64_t *) key1 > *(int64_t *) key2)
+ return 1;
+
+ return -1;
+}
+
+static int
+btree_compare_uint64(cont void *key1, int keylen1,
+ const void *key2, int keylen2)
+{
+ if (*(u_int64_t *) key1 == *(u_int64_t *) key2)
+ return 0;
+ else if (*(u_int64_t *) key1 > *(u_int64_t *) key2)
+ return 1;
+
+ return -1;
+}
+
+static int
+btree_compare_float(cont void *key1, int keylen1, const void *key2, int keylen2)
+{
+ float result = *(float *) key1 - *(float *) key2;
+ if (result == 0.0f)
+ return 0;
+
+ return (result < 0.0f) ? -1 : 1;
+}
+
+static int
+btree_compare_double(cont void *key1, int keylen1,
+ const void *key2, int keylen2)
+{
+ double result = *(double *) key1 - *(double *) key2;
+ if (result == 0.0)
+ return 0;
+
+ return (result < 0.0) ? -1 : 1;
+}
+#endif //0
Code Review / kvmfornfv.git / blobdiff