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Linux/lib/ucs2_string.c

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

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