[linux-cifs-client] [PATCH 1/3] cifs: Introduce helper to compute length of nls string in bytes

[Suresh Jayaraman]

Though the consensus is that we need a generalised helper to handle
unicode string buffers so that other filesystems could consume, we would
need a cifs helper like this in the interim, given the number of
discussions/reviews and bug reports. cifs could easily replace this with
generic helpers once such helper is in place.


Signed-off-by: Suresh Jayaraman <sjayaraman at suse.de>
---
 fs/cifs/cifs_unicode.h |   27 +++++++++++++++++++++++++++
 1 files changed, 27 insertions(+), 0 deletions(-)

diff --git a/fs/cifs/cifs_unicode.h b/fs/cifs/cifs_unicode.h
index 14eb9a2..8ab332b 100644
--- a/fs/cifs/cifs_unicode.h
+++ b/fs/cifs/cifs_unicode.h
@@ -159,6 +159,33 @@ UniStrnlen(const wchar_t *ucs1, int maxlen)
 }
 
 /*
+ * UniStrnlenBytes: Return the length of a NLS string in bytes. Also, populates
+ * 'nchars' with the length of string in 16 bit Unicode chars.
+ */
+static inline size_t
+UniStrnlenBytes(const wchar_t *str, int maxlen, int *nchars,
+		const struct nls_table *codepage)
+{
+	int nc;
+	size_t nbytes = 0;
+	char buf[NLS_MAX_CHARSET_SIZE]; /* enough for one char at a time */
+
+	*nchars = 0;
+	while (*str++ && maxlen) {
+		nc = codepage->uni2char(*str, buf, NLS_MAX_CHARSET_SIZE);
+		if (nc > 0)
+			nbytes += nc;
+		else
+			nbytes += 1; /* for '?' */
+		(*nchars)++;
+		if (*nchars >= maxlen)
+			break;
+	}
+
+	return nbytes;
+}
+
+/*
  * UniStrncat:  Concatenate length limited string
  */
 static inline wchar_t *