[PATCH v9 1/4] unicode: Add utf8_casefold_hash

Daniel Rosenberg
2020-06-24T04:34:11Z

This adds a case insensitive hash function to allow taking the hash
without needing to allocate a casefolded copy of the string.

Signed-off-by: Daniel Rosenberg <drosen@google.com>
---
fs/unicode/utf8-core.c | 23 ++++++++++++++++++++++-
include/linux/unicode.h | 3 +++
2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/fs/unicode/utf8-core.c b/fs/unicode/utf8-core.c
index 2a878b739115d..90656b9980720 100644
--- a/fs/unicode/utf8-core.c
+++ b/fs/unicode/utf8-core.c
@@ -6,6 +6,7 @@
#include <linux/parser.h>
#include <linux/errno.h>
#include <linux/unicode.h>
+#include <linux/stringhash.h>

#include "utf8n.h"

@@ -122,9 +123,29 @@ int utf8_casefold(const struct unicode_map *um, const struct qstr *str,
}
return -EINVAL;
}
-
EXPORT_SYMBOL(utf8_casefold);

+int utf8_casefold_hash(const struct unicode_map *um, const void *salt,
+ struct qstr *str)
+{
+ const struct utf8data *data = utf8nfdicf(um->version);
+ struct utf8cursor cur;
+ int c;
+ unsigned long hash = init_name_hash(salt);
+
+ if (utf8ncursor(&cur, data, str->name, str->len) < 0)
+ return -EINVAL;
+
+ while ((c = utf8byte(&cur))) {
+ if (c < 0)
+ return c;
+ hash = partial_name_hash((unsigned char)c, hash);
+ }
+ str->hash = end_name_hash(hash);
+ return 0;
+}
+EXPORT_SYMBOL(utf8_casefold_hash);
+
int utf8_normalize(const struct unicode_map *um, const struct qstr *str,
unsigned char *dest, size_t dlen)
{
diff --git a/include/linux/unicode.h b/include/linux/unicode.h
index 990aa97d80496..74484d44c7554 100644
--- a/include/linux/unicode.h
+++ b/include/linux/unicode.h
@@ -27,6 +27,9 @@ int utf8_normalize(const struct unicode_map *um, const struct qstr *str,
int utf8_casefold(const struct unicode_map *um, const struct qstr *str,
unsigned char *dest, size_t dlen);

+int utf8_casefold_hash(const struct unicode_map *um, const void *salt,
+ struct qstr *str);
+
struct unicode_map *utf8_load(const char *version);
void utf8_unload(struct unicode_map *um);

--
2.27.0.111.gc72c7da667-goog