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1// SPDX-License-Identifier: GPL-2.02#include <linux/ucs2_string.h>3#include <linux/module.h>4 5/* Return the number of unicode characters in data */6unsigned long7ucs2_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 long18ucs2_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 string26 * Note: this is NOT the same as the number of unicode characters27 */28unsigned long29ucs2_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 35/**36 * ucs2_strscpy() - Copy a UCS2 string into a sized buffer.37 *38 * @dst: Pointer to the destination buffer where to copy the string to.39 * @src: Pointer to the source buffer where to copy the string from.40 * @count: Size of the destination buffer, in UCS2 (16-bit) characters.41 *42 * Like strscpy(), only for UCS2 strings.43 *44 * Copy the source string @src, or as much of it as fits, into the destination45 * buffer @dst. The behavior is undefined if the string buffers overlap. The46 * destination buffer @dst is always NUL-terminated, unless it's zero-sized.47 *48 * Return: The number of characters copied into @dst (excluding the trailing49 * %NUL terminator) or -E2BIG if @count is 0 or @src was truncated due to the50 * destination buffer being too small.51 */52ssize_t ucs2_strscpy(ucs2_char_t *dst, const ucs2_char_t *src, size_t count)53{54 long res;55 56 /*57 * Ensure that we have a valid amount of space. We need to store at58 * least one NUL-character.59 */60 if (count == 0 || WARN_ON_ONCE(count > INT_MAX / sizeof(*dst)))61 return -E2BIG;62 63 /*64 * Copy at most 'count' characters, return early if we find a65 * NUL-terminator.66 */67 for (res = 0; res < count; res++) {68 ucs2_char_t c;69 70 c = src[res];71 dst[res] = c;72 73 if (!c)74 return res;75 }76 77 /*78 * The loop above terminated without finding a NUL-terminator,79 * exceeding the 'count': Enforce proper NUL-termination and return80 * error.81 */82 dst[count - 1] = 0;83 return -E2BIG;84}85EXPORT_SYMBOL(ucs2_strscpy);86 87int88ucs2_strncmp(const ucs2_char_t *a, const ucs2_char_t *b, size_t len)89{90 while (1) {91 if (len == 0)92 return 0;93 if (*a < *b)94 return -1;95 if (*a > *b)96 return 1;97 if (*a == 0) /* implies *b == 0 */98 return 0;99 a++;100 b++;101 len--;102 }103}104EXPORT_SYMBOL(ucs2_strncmp);105 106unsigned long107ucs2_utf8size(const ucs2_char_t *src)108{109 unsigned long i;110 unsigned long j = 0;111 112 for (i = 0; src[i]; i++) {113 u16 c = src[i];114 115 if (c >= 0x800)116 j += 3;117 else if (c >= 0x80)118 j += 2;119 else120 j += 1;121 }122 123 return j;124}125EXPORT_SYMBOL(ucs2_utf8size);126 127/*128 * copy at most maxlength bytes of whole utf8 characters to dest from the129 * ucs2 string src.130 *131 * The return value is the number of characters copied, not including the132 * final NUL character.133 */134unsigned long135ucs2_as_utf8(u8 *dest, const ucs2_char_t *src, unsigned long maxlength)136{137 unsigned int i;138 unsigned long j = 0;139 unsigned long limit = ucs2_strnlen(src, maxlength);140 141 for (i = 0; maxlength && i < limit; i++) {142 u16 c = src[i];143 144 if (c >= 0x800) {145 if (maxlength < 3)146 break;147 maxlength -= 3;148 dest[j++] = 0xe0 | (c & 0xf000) >> 12;149 dest[j++] = 0x80 | (c & 0x0fc0) >> 6;150 dest[j++] = 0x80 | (c & 0x003f);151 } else if (c >= 0x80) {152 if (maxlength < 2)153 break;154 maxlength -= 2;155 dest[j++] = 0xc0 | (c & 0x7c0) >> 6;156 dest[j++] = 0x80 | (c & 0x03f);157 } else {158 maxlength -= 1;159 dest[j++] = c & 0x7f;160 }161 }162 if (maxlength)163 dest[j] = '\0';164 return j;165}166EXPORT_SYMBOL(ucs2_as_utf8);167 168MODULE_LICENSE("GPL v2");169