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-rw-r--r--lib/ucs2_string.c52
1 files changed, 52 insertions, 0 deletions
diff --git a/lib/ucs2_string.c b/lib/ucs2_string.c
index 0a559a42359b..9308bcfb2ad5 100644
--- a/lib/ucs2_string.c
+++ b/lib/ucs2_string.c
@@ -32,6 +32,58 @@ ucs2_strsize(const ucs2_char_t *data, unsigned long maxlength)
}
EXPORT_SYMBOL(ucs2_strsize);
+/**
+ * ucs2_strscpy() - Copy a UCS2 string into a sized buffer.
+ *
+ * @dst: Pointer to the destination buffer where to copy the string to.
+ * @src: Pointer to the source buffer where to copy the string from.
+ * @count: Size of the destination buffer, in UCS2 (16-bit) characters.
+ *
+ * Like strscpy(), only for UCS2 strings.
+ *
+ * Copy the source string @src, or as much of it as fits, into the destination
+ * buffer @dst. The behavior is undefined if the string buffers overlap. The
+ * destination buffer @dst is always NUL-terminated, unless it's zero-sized.
+ *
+ * Return: The number of characters copied into @dst (excluding the trailing
+ * %NUL terminator) or -E2BIG if @count is 0 or @src was truncated due to the
+ * destination buffer being too small.
+ */
+ssize_t ucs2_strscpy(ucs2_char_t *dst, const ucs2_char_t *src, size_t count)
+{
+ long res;
+
+ /*
+ * Ensure that we have a valid amount of space. We need to store at
+ * least one NUL-character.
+ */
+ if (count == 0 || WARN_ON_ONCE(count > INT_MAX / sizeof(*dst)))
+ return -E2BIG;
+
+ /*
+ * Copy at most 'count' characters, return early if we find a
+ * NUL-terminator.
+ */
+ for (res = 0; res < count; res++) {
+ ucs2_char_t c;
+
+ c = src[res];
+ dst[res] = c;
+
+ if (!c)
+ return res;
+ }
+
+ /*
+ * The loop above terminated without finding a NUL-terminator,
+ * exceeding the 'count': Enforce proper NUL-termination and return
+ * error.
+ */
+ dst[count - 1] = 0;
+ return -E2BIG;
+}
+EXPORT_SYMBOL(ucs2_strscpy);
+
int
ucs2_strncmp(const ucs2_char_t *a, const ucs2_char_t *b, size_t len)
{