1// SPDX-License-Identifier: GPL-2.0
2#include <linux/ucs2_string.h>
3#include <linux/module.h>
4
5/* Return the number of unicode characters in data */
6unsigned long
7ucs2_strnlen(const ucs2_char_t *s, size_t maxlength)
8{
9 unsigned long length = 0;
10
11 while (*s++ != 0 && length < maxlength)
12 length++;
13 return length;
14}
15EXPORT_SYMBOL(ucs2_strnlen);
16
17unsigned long
18ucs2_strlen(const ucs2_char_t *s)
19{
20 return ucs2_strnlen(s, ~0UL);
21}
22EXPORT_SYMBOL(ucs2_strlen);
23
24/*
25 * Return the number of bytes is the length of this string
26 * Note: this is NOT the same as the number of unicode characters
27 */
28unsigned long
29ucs2_strsize(const ucs2_char_t *data, unsigned long maxlength)
30{
31 return ucs2_strnlen(data, maxlength/sizeof(ucs2_char_t)) * sizeof(ucs2_char_t);
32}
33EXPORT_SYMBOL(ucs2_strsize);
34
35int
36ucs2_strncmp(const ucs2_char_t *a, const ucs2_char_t *b, size_t len)
37{
38 while (1) {
39 if (len == 0)
40 return 0;
41 if (*a < *b)
42 return -1;
43 if (*a > *b)
44 return 1;
45 if (*a == 0) /* implies *b == 0 */
46 return 0;
47 a++;
48 b++;
49 len--;
50 }
51}
52EXPORT_SYMBOL(ucs2_strncmp);
53
54unsigned long
55ucs2_utf8size(const ucs2_char_t *src)
56{
57 unsigned long i;
58 unsigned long j = 0;
59
60 for (i = 0; src[i]; i++) {
61 u16 c = src[i];
62
63 if (c >= 0x800)
64 j += 3;
65 else if (c >= 0x80)
66 j += 2;
67 else
68 j += 1;
69 }
70
71 return j;
72}
73EXPORT_SYMBOL(ucs2_utf8size);
74
75/*
76 * copy at most maxlength bytes of whole utf8 characters to dest from the
77 * ucs2 string src.
78 *
79 * The return value is the number of characters copied, not including the
80 * final NUL character.
81 */
82unsigned long
83ucs2_as_utf8(u8 *dest, const ucs2_char_t *src, unsigned long maxlength)
84{
85 unsigned int i;
86 unsigned long j = 0;
87 unsigned long limit = ucs2_strnlen(src, maxlength);
88
89 for (i = 0; maxlength && i < limit; i++) {
90 u16 c = src[i];
91
92 if (c >= 0x800) {
93 if (maxlength < 3)
94 break;
95 maxlength -= 3;
96 dest[j++] = 0xe0 | (c & 0xf000) >> 12;
97 dest[j++] = 0x80 | (c & 0x0fc0) >> 6;
98 dest[j++] = 0x80 | (c & 0x003f);
99 } else if (c >= 0x80) {
100 if (maxlength < 2)
101 break;
102 maxlength -= 2;
103 dest[j++] = 0xc0 | (c & 0x7c0) >> 6;
104 dest[j++] = 0x80 | (c & 0x03f);
105 } else {
106 maxlength -= 1;
107 dest[j++] = c & 0x7f;
108 }
109 }
110 if (maxlength)
111 dest[j] = '\0';
112 return j;
113}
114EXPORT_SYMBOL(ucs2_as_utf8);
115
116MODULE_LICENSE("GPL v2");
117