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authorPeter Jones <pjones@redhat.com>2016-02-08 14:48:11 -0500
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-03-16 08:42:20 -0700
commit002f14d470825598cca1ab3c3a97d8eb1c026613 (patch)
tree7d8c3baca032b4a987f08e164a28bdc78281eb9c
parent444b361a4f2ca31a37da7610cec22dfab98b82c3 (diff)
lib/ucs2_string: Add ucs2 -> utf8 helper functions
commit 73500267c930baadadb0d02284909731baf151f7 upstream. This adds ucs2_utf8size(), which tells us how big our ucs2 string is in bytes, and ucs2_as_utf8, which translates from ucs2 to utf8.. Signed-off-by: Peter Jones <pjones@redhat.com> Tested-by: Lee, Chun-Yi <jlee@suse.com> Acked-by: Matthew Garrett <mjg59@coreos.com> Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--include/linux/ucs2_string.h4
-rw-r--r--lib/ucs2_string.c62
2 files changed, 66 insertions, 0 deletions
diff --git a/include/linux/ucs2_string.h b/include/linux/ucs2_string.h
index cbb20afdbc01..bb679b48f408 100644
--- a/include/linux/ucs2_string.h
+++ b/include/linux/ucs2_string.h
@@ -11,4 +11,8 @@ unsigned long ucs2_strlen(const ucs2_char_t *s);
unsigned long ucs2_strsize(const ucs2_char_t *data, unsigned long maxlength);
int ucs2_strncmp(const ucs2_char_t *a, const ucs2_char_t *b, size_t len);
+unsigned long ucs2_utf8size(const ucs2_char_t *src);
+unsigned long ucs2_as_utf8(u8 *dest, const ucs2_char_t *src,
+ unsigned long maxlength);
+
#endif /* _LINUX_UCS2_STRING_H_ */
diff --git a/lib/ucs2_string.c b/lib/ucs2_string.c
index 6f500ef2301d..17dd74e21ef9 100644
--- a/lib/ucs2_string.c
+++ b/lib/ucs2_string.c
@@ -49,3 +49,65 @@ ucs2_strncmp(const ucs2_char_t *a, const ucs2_char_t *b, size_t len)
}
}
EXPORT_SYMBOL(ucs2_strncmp);
+
+unsigned long
+ucs2_utf8size(const ucs2_char_t *src)
+{
+ unsigned long i;
+ unsigned long j = 0;
+
+ for (i = 0; i < ucs2_strlen(src); i++) {
+ u16 c = src[i];
+
+ if (c > 0x800)
+ j += 3;
+ else if (c > 0x80)
+ j += 2;
+ else
+ j += 1;
+ }
+
+ return j;
+}
+EXPORT_SYMBOL(ucs2_utf8size);
+
+/*
+ * copy at most maxlength bytes of whole utf8 characters to dest from the
+ * ucs2 string src.
+ *
+ * The return value is the number of characters copied, not including the
+ * final NUL character.
+ */
+unsigned long
+ucs2_as_utf8(u8 *dest, const ucs2_char_t *src, unsigned long maxlength)
+{
+ unsigned int i;
+ unsigned long j = 0;
+ unsigned long limit = ucs2_strnlen(src, maxlength);
+
+ for (i = 0; maxlength && i < limit; i++) {
+ u16 c = src[i];
+
+ if (c > 0x800) {
+ if (maxlength < 3)
+ break;
+ maxlength -= 3;
+ dest[j++] = 0xe0 | (c & 0xf000) >> 12;
+ dest[j++] = 0x80 | (c & 0x0fc0) >> 8;
+ dest[j++] = 0x80 | (c & 0x003f);
+ } else if (c > 0x80) {
+ if (maxlength < 2)
+ break;
+ maxlength -= 2;
+ dest[j++] = 0xc0 | (c & 0xfe0) >> 5;
+ dest[j++] = 0x80 | (c & 0x01f);
+ } else {
+ maxlength -= 1;
+ dest[j++] = c & 0x7f;
+ }
+ }
+ if (maxlength)
+ dest[j] = '\0';
+ return j;
+}
+EXPORT_SYMBOL(ucs2_as_utf8);