NLS: improve UTF8 -> UTF16 string conversion routine
[pandora-kernel.git] / fs / nls / nls_base.c
index 44a88a9..0eb059e 100644 (file)
@@ -114,34 +114,57 @@ int utf32_to_utf8(unicode_t u, u8 *s, int maxlen)
 }
 EXPORT_SYMBOL(utf32_to_utf8);
 
-int utf8s_to_utf16s(const u8 *s, int len, wchar_t *pwcs)
+static inline void put_utf16(wchar_t *s, unsigned c, enum utf16_endian endian)
+{
+       switch (endian) {
+       default:
+               *s = (wchar_t) c;
+               break;
+       case UTF16_LITTLE_ENDIAN:
+               *s = __cpu_to_le16(c);
+               break;
+       case UTF16_BIG_ENDIAN:
+               *s = __cpu_to_be16(c);
+               break;
+       }
+}
+
+int utf8s_to_utf16s(const u8 *s, int len, enum utf16_endian endian,
+               wchar_t *pwcs, int maxlen)
 {
        u16 *op;
        int size;
        unicode_t u;
 
        op = pwcs;
-       while (*s && len > 0) {
+       while (len > 0 && maxlen > 0 && *s) {
                if (*s & 0x80) {
                        size = utf8_to_utf32(s, len, &u);
                        if (size < 0)
                                return -EINVAL;
+                       s += size;
+                       len -= size;
 
                        if (u >= PLANE_SIZE) {
+                               if (maxlen < 2)
+                                       break;
                                u -= PLANE_SIZE;
-                               *op++ = (wchar_t) (SURROGATE_PAIR |
-                                               ((u >> 10) & SURROGATE_BITS));
-                               *op++ = (wchar_t) (SURROGATE_PAIR |
+                               put_utf16(op++, SURROGATE_PAIR |
+                                               ((u >> 10) & SURROGATE_BITS),
+                                               endian);
+                               put_utf16(op++, SURROGATE_PAIR |
                                                SURROGATE_LOW |
-                                               (u & SURROGATE_BITS));
+                                               (u & SURROGATE_BITS),
+                                               endian);
+                               maxlen -= 2;
                        } else {
-                               *op++ = (wchar_t) u;
+                               put_utf16(op++, u, endian);
+                               maxlen--;
                        }
-                       s += size;
-                       len -= size;
                } else {
-                       *op++ = *s++;
+                       put_utf16(op++, *s++, endian);
                        len--;
+                       maxlen--;
                }
        }
        return op - pwcs;