patch-2.4.22 linux-2.4.22/fs/hfsplus/bfind.c

• Lines: 214
• Date: 2003-08-25 04:44:43.000000000 -0700
• Orig file: linux-2.4.21/fs/hfsplus/bfind.c
• Orig date: 1969-12-31 16:00:00.000000000 -0800

diff -urN linux-2.4.21/fs/hfsplus/bfind.c linux-2.4.22/fs/hfsplus/bfind.c
@@ -0,0 +1,213 @@
+/*
+ *  linux/fs/hfsplus/bfind.c
+ *
+ * Copyright (C) 2001
+ * Brad Boyer (flar@allandria.com)
+ * (C) 2003 Ardis Technologies <roman@ardistech.com>
+ *
+ * Search routines for btrees
+ */
+
+#include <linux/slab.h>
+#include "hfsplus_fs.h"
+
+/* Find the record in bnode that best matches key (not greater than...)*/
+void hfsplus_find_rec(hfsplus_bnode *bnode, struct hfsplus_find_data *fd)
+{
+	int cmpval;
+	u16 off, len, keylen;
+	int rec;
+	int b, e;
+
+	b = 0;
+	e = bnode->num_recs - 1;
+	do {
+		rec = (e + b) / 2;
+		len = hfsplus_brec_lenoff(bnode, rec, &off);
+		keylen = hfsplus_brec_keylen(bnode, rec);
+		hfsplus_bnode_readbytes(bnode, fd->key, off, keylen);
+		cmpval = bnode->tree->keycmp(fd->key, fd->search_key);
+		if (!cmpval) {
+			fd->exact = 1;
+			e = rec;
+			break;
+		}
+		if (cmpval < 0)
+			b = rec + 1;
+		else
+			e = rec - 1;
+	} while (b <= e);
+	//printk("%d: %d,%d,%d\n", bnode->this, b, e, rec);
+	if (rec != e && e >= 0) {
+		len = hfsplus_brec_lenoff(bnode, e, &off);
+		keylen = hfsplus_brec_keylen(bnode, e);
+		hfsplus_bnode_readbytes(bnode, fd->key, off, keylen);
+	}
+	fd->record = e;
+	fd->keyoffset = off;
+	fd->keylength = keylen;
+	fd->entryoffset = off + keylen;
+	fd->entrylength = len - keylen;
+}
+
+/* Traverse a B*Tree from the root to a leaf finding best fit to key */
+/* Return allocated copy of node found, set recnum to best record */
+int hfsplus_btree_find(struct hfsplus_find_data *fd)
+{
+	hfsplus_btree *tree;
+	hfsplus_bnode *bnode;
+	u32 data, nidx, parent;
+	int height, err;
+
+	tree = fd->tree;
+	if (fd->bnode)
+		hfsplus_put_bnode(fd->bnode);
+	fd->bnode = NULL;
+	fd->exact = 0;
+	nidx = tree->root;
+	if (!nidx)
+		return -ENOENT;
+	height = tree->depth;
+	err = 0;
+	parent = 0;
+	for (;;) {
+		bnode = hfsplus_find_bnode(tree, nidx);
+		if (!bnode) {
+			err = -EIO;
+			break;
+		}
+		if (bnode->height != height)
+			goto invalid;
+		if (bnode->kind != (--height ? HFSPLUS_NODE_NDX : HFSPLUS_NODE_LEAF))
+			goto invalid;
+		bnode->parent = parent;
+
+		hfsplus_find_rec(bnode, fd);
+		if (fd->record < 0) {
+			err = -ENOENT;
+			goto release;
+		}
+		if (!height) {
+			if (!fd->exact)
+				err = -ENOENT;
+			break;
+		}
+
+		parent = nidx;
+		hfsplus_bnode_readbytes(bnode, &data, fd->entryoffset, 4);
+		nidx = be32_to_cpu(data);
+		hfsplus_put_bnode(bnode);
+	}
+	fd->bnode = bnode;
+	return err;
+
+invalid:
+	printk("HFS+-fs: inconsistency in B*Tree\n");
+	err = -EIO;
+release:
+	hfsplus_put_bnode(bnode);
+	return err;
+}
+
+int hfsplus_btree_find_entry(struct hfsplus_find_data *fd,
+			     void *entry, int entry_len)
+{
+	int res;
+
+	res = hfsplus_btree_find(fd);
+	if (res)
+		return res;
+	if (fd->entrylength > entry_len)
+		return -EINVAL;
+	hfsplus_bnode_readbytes(fd->bnode, entry, fd->entryoffset, fd->entrylength);
+	return 0;
+}
+
+int hfsplus_btree_move(struct hfsplus_find_data *fd, int cnt)
+{
+	struct hfsplus_btree *tree;
+	hfsplus_bnode *bnode;
+	int idx, res = 0;
+	u16 off, len, keylen;
+
+	bnode = fd->bnode;
+	tree = bnode->tree;
+
+	if (cnt < -0xFFFF || cnt > 0xFFFF)
+		return -EINVAL;
+
+	if (cnt < 0) {
+		cnt = -cnt;
+		while (cnt > fd->record) {
+			cnt -= fd->record + 1;
+			fd->record = bnode->num_recs - 1;
+			idx = bnode->prev;
+			if (!idx) {
+				res = -ENOENT;
+				goto out;
+			}
+			hfsplus_put_bnode(bnode);
+			bnode = hfsplus_find_bnode(tree, idx);
+			if (!bnode) {
+				res = -EIO;
+				goto out;
+			}
+		}
+		fd->record -= cnt;
+	} else {
+		while (cnt >= bnode->num_recs - fd->record) {
+			cnt -= bnode->num_recs - fd->record;
+			fd->record = 0;
+			idx = bnode->next;
+			if (!idx) {
+				res = -ENOENT;
+				goto out;
+			}
+			hfsplus_put_bnode(bnode);
+			bnode = hfsplus_find_bnode(tree, idx);
+			if (!bnode) {
+				res = -EIO;
+				goto out;
+			}
+		}
+		fd->record += cnt;
+	}
+
+	len = hfsplus_brec_lenoff(bnode, fd->record, &off);
+	keylen = hfsplus_brec_keylen(bnode, fd->record);
+	fd->keyoffset = off;
+	fd->keylength = keylen;
+	fd->entryoffset = off + keylen;
+	fd->entrylength = len - keylen;
+	hfsplus_bnode_readbytes(bnode, fd->key, off, keylen);
+out:
+	fd->bnode = bnode;
+	return res;
+}
+
+int hfsplus_find_init(hfsplus_btree *tree, struct hfsplus_find_data *fd)
+{
+	fd->tree = tree;
+	fd->bnode = NULL;
+	fd->search_key = kmalloc(tree->max_key_len + 2, GFP_KERNEL);
+	if (!fd->search_key)
+		return -ENOMEM;
+	fd->key = kmalloc(tree->max_key_len + 2, GFP_KERNEL);
+	if (!fd->key) {
+		kfree(fd->search_key);
+		return -ENOMEM;
+	}
+	dprint(DBG_BNODE_REFS, "find_init: %d (%p)\n", tree->cnid, __builtin_return_address(0));
+	down(&tree->tree_lock);
+	return 0;
+}
+
+void hfsplus_find_exit(struct hfsplus_find_data *fd)
+{
+	hfsplus_put_bnode(fd->bnode);
+	kfree(fd->search_key);
+	kfree(fd->key);
+	dprint(DBG_BNODE_REFS, "find_exit: %d (%p)\n", fd->tree->cnid, __builtin_return_address(0));
+	up(&fd->tree->tree_lock);
+	fd->tree = NULL;
+}