diff options
author | Peter Jones <pjones@redhat.com> | 2016-02-08 14:48:11 -0500 |
---|---|---|
committer | Matt Fleming <matt@codeblueprint.co.uk> | 2016-02-10 13:19:03 +0000 |
commit | 73500267c930baadadb0d02284909731baf151f7 (patch) | |
tree | 431f07c5786db95d33f0f6d557cdba1881da29e3 /lib/ucs2_string.c | |
parent | 59fd1214561921343305a0e9dc218bf3d40068f3 (diff) | |
download | linux-rt-73500267c930baadadb0d02284909731baf151f7.tar.gz |
lib/ucs2_string: Add ucs2 -> utf8 helper functions
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>
Diffstat (limited to 'lib/ucs2_string.c')
-rw-r--r-- | lib/ucs2_string.c | 62 |
1 files changed, 62 insertions, 0 deletions
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); |