This patch (as1502) removes the UTF8-to-UTF16 conversion routine in
the USB gadget library and replaces it with a call to the equivalent
function in the NLS library.
The only downside worth noting is that the NLS library routine
requires the output buffer to be 16-bit aligned. This is always true
in the gadget code, because the output buffer is always a
usb_request buffer being used to send a string descriptor.
Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/gadget/Kconfig | 1
drivers/usb/gadget/usbstring.c | 73 ++---------------------------------------
2 files changed, 5 insertions(+), 69 deletions(-)
Index: usb-3.2/drivers/usb/gadget/Kconfig
===================================================================
--- usb-3.2.orig/drivers/usb/gadget/Kconfig
+++ usb-3.2/drivers/usb/gadget/Kconfig
@@ -15,6 +15,7 @@
menuconfig USB_GADGET
tristate "USB Gadget Support"
+ select NLS
help
USB is a master/slave protocol, organized with one master
host (such as a PC) controlling up to 127 peripheral devices.
Index: usb-3.2/drivers/usb/gadget/usbstring.c
===================================================================
--- usb-3.2.orig/drivers/usb/gadget/usbstring.c
+++ usb-3.2/drivers/usb/gadget/usbstring.c
@@ -13,82 +13,17 @@
#include <linux/string.h>
#include <linux/device.h>
#include <linux/init.h>
+#include <linux/nls.h>
#include <linux/usb/ch9.h>
#include <linux/usb/gadget.h>
-#include <asm/unaligned.h>
-
-
-static int utf8_to_utf16le(const char *s, __le16 *cp, unsigned len)
-{
- int count = 0;
- u8 c;
- u16 uchar;
-
- /* this insists on correct encodings, though not minimal ones.
- * BUT it currently rejects legit 4-byte UTF-8 code points,
- * which need surrogate pairs. (Unicode 3.1 can use them.)
- */
- while (len != 0 && (c = (u8) *s++) != 0) {
- if (unlikely(c & 0x80)) {
- // 2-byte sequence:
- // 00000yyyyyxxxxxx = 110yyyyy 10xxxxxx
- if ((c & 0xe0) == 0xc0) {
- uchar = (c & 0x1f) << 6;
-
- c = (u8) *s++;
- if ((c & 0xc0) != 0x80)
- goto fail;
- c &= 0x3f;
- uchar |= c;
-
- // 3-byte sequence (most CJKV characters):
- // zzzzyyyyyyxxxxxx = 1110zzzz 10yyyyyy 10xxxxxx
- } else if ((c & 0xf0) == 0xe0) {
- uchar = (c & 0x0f) << 12;
-
- c = (u8) *s++;
- if ((c & 0xc0) != 0x80)
- goto fail;
- c &= 0x3f;
- uchar |= c << 6;
-
- c = (u8) *s++;
- if ((c & 0xc0) != 0x80)
- goto fail;
- c &= 0x3f;
- uchar |= c;
-
- /* no bogus surrogates */
- if (0xd800 <= uchar && uchar <= 0xdfff)
- goto fail;
-
- // 4-byte sequence (surrogate pairs, currently rare):
- // 11101110wwwwzzzzyy + 110111yyyyxxxxxx
- // = 11110uuu 10uuzzzz 10yyyyyy 10xxxxxx
- // (uuuuu = wwww + 1)
- // FIXME accept the surrogate code points (only)
-
- } else
- goto fail;
- } else
- uchar = c;
- put_unaligned_le16(uchar, cp++);
- count++;
- len--;
- }
- return count;
-fail:
- return -1;
-}
-
/**
* usb_gadget_get_string - fill out a string descriptor
* @table: of c strings encoded using UTF-8
* @id: string id, from low byte of wValue in get string descriptor
- * @buf: at least 256 bytes
+ * @buf: at least 256 bytes, must be 16-bit aligned
*
* Finds the UTF-8 string matching the ID, and converts it into a
* string descriptor in utf16-le.
@@ -125,8 +60,8 @@ usb_gadget_get_string (struct usb_gadget
/* string descriptors have length, tag, then UTF16-LE text */
len = min ((size_t) 126, strlen (s->s));
- memset (buf + 2, 0, 2 * len); /* zero all the bytes */
- len = utf8_to_utf16le(s->s, (__le16 *)&buf[2], len);
+ len = utf8s_to_utf16s(s->s, len, UTF16_LITTLE_ENDIAN,
+ (wchar_t *) &buf[2], 126);
if (len < 0)
return -EINVAL;
buf [0] = (len + 1) * 2;
--
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