cf289cefbf
No need to calculate the string length on every loop iteration. Signed-off-by: Lukas Wunner <lukas@wunner.de> Cc: Peter Jones <pjones@redhat.com> Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
114 lines
2.4 KiB
C
114 lines
2.4 KiB
C
#include <linux/ucs2_string.h>
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#include <linux/module.h>
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/* Return the number of unicode characters in data */
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unsigned long
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ucs2_strnlen(const ucs2_char_t *s, size_t maxlength)
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{
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unsigned long length = 0;
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while (*s++ != 0 && length < maxlength)
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length++;
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return length;
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}
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EXPORT_SYMBOL(ucs2_strnlen);
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unsigned long
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ucs2_strlen(const ucs2_char_t *s)
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{
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return ucs2_strnlen(s, ~0UL);
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}
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EXPORT_SYMBOL(ucs2_strlen);
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/*
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* Return the number of bytes is the length of this string
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* Note: this is NOT the same as the number of unicode characters
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*/
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unsigned long
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ucs2_strsize(const ucs2_char_t *data, unsigned long maxlength)
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{
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return ucs2_strnlen(data, maxlength/sizeof(ucs2_char_t)) * sizeof(ucs2_char_t);
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}
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EXPORT_SYMBOL(ucs2_strsize);
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int
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ucs2_strncmp(const ucs2_char_t *a, const ucs2_char_t *b, size_t len)
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{
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while (1) {
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if (len == 0)
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return 0;
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if (*a < *b)
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return -1;
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if (*a > *b)
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return 1;
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if (*a == 0) /* implies *b == 0 */
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return 0;
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a++;
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b++;
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len--;
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}
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}
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EXPORT_SYMBOL(ucs2_strncmp);
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unsigned long
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ucs2_utf8size(const ucs2_char_t *src)
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{
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unsigned long i;
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unsigned long j = 0;
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for (i = 0; src[i]; i++) {
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u16 c = src[i];
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if (c >= 0x800)
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j += 3;
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else if (c >= 0x80)
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j += 2;
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else
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j += 1;
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}
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return j;
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}
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EXPORT_SYMBOL(ucs2_utf8size);
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/*
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* copy at most maxlength bytes of whole utf8 characters to dest from the
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* ucs2 string src.
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*
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* The return value is the number of characters copied, not including the
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* final NUL character.
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*/
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unsigned long
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ucs2_as_utf8(u8 *dest, const ucs2_char_t *src, unsigned long maxlength)
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{
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unsigned int i;
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unsigned long j = 0;
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unsigned long limit = ucs2_strnlen(src, maxlength);
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for (i = 0; maxlength && i < limit; i++) {
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u16 c = src[i];
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if (c >= 0x800) {
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if (maxlength < 3)
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break;
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maxlength -= 3;
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dest[j++] = 0xe0 | (c & 0xf000) >> 12;
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dest[j++] = 0x80 | (c & 0x0fc0) >> 6;
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dest[j++] = 0x80 | (c & 0x003f);
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} else if (c >= 0x80) {
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if (maxlength < 2)
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break;
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maxlength -= 2;
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dest[j++] = 0xc0 | (c & 0x7c0) >> 6;
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dest[j++] = 0x80 | (c & 0x03f);
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} else {
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maxlength -= 1;
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dest[j++] = c & 0x7f;
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}
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}
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if (maxlength)
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dest[j] = '\0';
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return j;
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}
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EXPORT_SYMBOL(ucs2_as_utf8);
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