HFS+: add custom dentry hash and comparison operations
Add custom dentry hash and comparison operations for HFS+ filesystems that are
case-insensitive and/or do automatic unicode decomposition. The new
operations reuse the existing HFS+ ASCII to unicode conversion, unicode
decomposition and case folding functionality.
Signed-off-by: Duane Griffin <duaneg@dghda.com>
Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/hfsplus/unicode.c b/fs/hfsplus/unicode.c
index 5df0052..9e10f94 100644
--- a/fs/hfsplus/unicode.c
+++ b/fs/hfsplus/unicode.c
@@ -314,3 +314,126 @@
return -ENAMETOOLONG;
return 0;
}
+
+/*
+ * Hash a string to an integer as appropriate for the HFS+ filesystem.
+ * Composed unicode characters are decomposed and case-folding is performed
+ * if the appropriate bits are (un)set on the superblock.
+ */
+int hfsplus_hash_dentry(struct dentry *dentry, struct qstr *str)
+{
+ struct super_block *sb = dentry->d_sb;
+ const char *astr;
+ const u16 *dstr;
+ int casefold, decompose, size, dsize, len;
+ unsigned long hash;
+ wchar_t c;
+ u16 c2;
+
+ casefold = (HFSPLUS_SB(sb).flags & HFSPLUS_SB_CASEFOLD);
+ decompose = !(HFSPLUS_SB(sb).flags & HFSPLUS_SB_NODECOMPOSE);
+ hash = init_name_hash();
+ astr = str->name;
+ len = str->len;
+ while (len > 0) {
+ size = asc2unichar(sb, astr, len, &c);
+ astr += size;
+ len -= size;
+
+ if (decompose && (dstr = decompose_unichar(c, &dsize))) {
+ do {
+ c2 = *dstr++;
+ if (!casefold || (c2 = case_fold(c2)))
+ hash = partial_name_hash(c2, hash);
+ } while (--dsize > 0);
+ } else {
+ c2 = c;
+ if (!casefold || (c2 = case_fold(c2)))
+ hash = partial_name_hash(c2, hash);
+ }
+ }
+ str->hash = end_name_hash(hash);
+
+ return 0;
+}
+
+/*
+ * Compare strings with HFS+ filename ordering.
+ * Composed unicode characters are decomposed and case-folding is performed
+ * if the appropriate bits are (un)set on the superblock.
+ */
+int hfsplus_compare_dentry(struct dentry *dentry, struct qstr *s1, struct qstr *s2)
+{
+ struct super_block *sb = dentry->d_sb;
+ int casefold, decompose, size;
+ int dsize1, dsize2, len1, len2;
+ const u16 *dstr1, *dstr2;
+ const char *astr1, *astr2;
+ u16 c1, c2;
+ wchar_t c;
+
+ casefold = (HFSPLUS_SB(sb).flags & HFSPLUS_SB_CASEFOLD);
+ decompose = !(HFSPLUS_SB(sb).flags & HFSPLUS_SB_NODECOMPOSE);
+ astr1 = s1->name;
+ len1 = s1->len;
+ astr2 = s2->name;
+ len2 = s2->len;
+ dsize1 = dsize2 = 0;
+ dstr1 = dstr2 = NULL;
+
+ while (len1 > 0 && len2 > 0) {
+ if (!dsize1) {
+ size = asc2unichar(sb, astr1, len1, &c);
+ astr1 += size;
+ len1 -= size;
+
+ if (!decompose || !(dstr1 = decompose_unichar(c, &dsize1))) {
+ c1 = c;
+ dstr1 = &c1;
+ dsize1 = 1;
+ }
+ }
+
+ if (!dsize2) {
+ size = asc2unichar(sb, astr2, len2, &c);
+ astr2 += size;
+ len2 -= size;
+
+ if (!decompose || !(dstr2 = decompose_unichar(c, &dsize2))) {
+ c2 = c;
+ dstr2 = &c2;
+ dsize2 = 1;
+ }
+ }
+
+ c1 = *dstr1;
+ c2 = *dstr2;
+ if (casefold) {
+ if (!(c1 = case_fold(c1))) {
+ dstr1++;
+ dsize1--;
+ continue;
+ }
+ if (!(c2 = case_fold(c2))) {
+ dstr2++;
+ dsize2--;
+ continue;
+ }
+ }
+ if (c1 < c2)
+ return -1;
+ else if (c1 > c2)
+ return 1;
+
+ dstr1++;
+ dsize1--;
+ dstr2++;
+ dsize2--;
+ }
+
+ if (len1 < len2)
+ return -1;
+ if (len1 > len2)
+ return 1;
+ return 0;
+}