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- // SPDX-License-Identifier: GPL-2.0+
- /*
- * charset conversion utils
- *
- * Copyright (c) 2017 Rob Clark
- */
- #include <charset.h>
- #include <malloc.h>
- /*
- * utf8/utf16 conversion mostly lifted from grub
- */
- size_t utf16_strlen(const uint16_t *in)
- {
- size_t i;
- for (i = 0; in[i]; i++);
- return i;
- }
- size_t utf16_strnlen(const uint16_t *in, size_t count)
- {
- size_t i;
- for (i = 0; count-- && in[i]; i++);
- return i;
- }
- uint16_t *utf16_strcpy(uint16_t *dest, const uint16_t *src)
- {
- uint16_t *tmp = dest;
- while ((*dest++ = *src++) != '\0')
- /* nothing */;
- return tmp;
- }
- uint16_t *utf16_strdup(const uint16_t *s)
- {
- uint16_t *new;
- if (!s || !(new = malloc((utf16_strlen(s) + 1) * 2)))
- return NULL;
- utf16_strcpy(new, s);
- return new;
- }
- /* Convert UTF-16 to UTF-8. */
- uint8_t *utf16_to_utf8(uint8_t *dest, const uint16_t *src, size_t size)
- {
- uint32_t code_high = 0;
- while (size--) {
- uint32_t code = *src++;
- if (code_high) {
- if (code >= 0xDC00 && code <= 0xDFFF) {
- /* Surrogate pair. */
- code = ((code_high - 0xD800) << 10) + (code - 0xDC00) + 0x10000;
- *dest++ = (code >> 18) | 0xF0;
- *dest++ = ((code >> 12) & 0x3F) | 0x80;
- *dest++ = ((code >> 6) & 0x3F) | 0x80;
- *dest++ = (code & 0x3F) | 0x80;
- } else {
- /* Error... */
- *dest++ = '?';
- /* *src may be valid. Don't eat it. */
- src--;
- }
- code_high = 0;
- } else {
- if (code <= 0x007F) {
- *dest++ = code;
- } else if (code <= 0x07FF) {
- *dest++ = (code >> 6) | 0xC0;
- *dest++ = (code & 0x3F) | 0x80;
- } else if (code >= 0xD800 && code <= 0xDBFF) {
- code_high = code;
- continue;
- } else if (code >= 0xDC00 && code <= 0xDFFF) {
- /* Error... */
- *dest++ = '?';
- } else if (code < 0x10000) {
- *dest++ = (code >> 12) | 0xE0;
- *dest++ = ((code >> 6) & 0x3F) | 0x80;
- *dest++ = (code & 0x3F) | 0x80;
- } else {
- *dest++ = (code >> 18) | 0xF0;
- *dest++ = ((code >> 12) & 0x3F) | 0x80;
- *dest++ = ((code >> 6) & 0x3F) | 0x80;
- *dest++ = (code & 0x3F) | 0x80;
- }
- }
- }
- return dest;
- }
- uint16_t *utf8_to_utf16(uint16_t *dest, const uint8_t *src, size_t size)
- {
- while (size--) {
- int extension_bytes;
- uint32_t code;
- extension_bytes = 0;
- if (*src <= 0x7f) {
- code = *src++;
- /* Exit on zero byte */
- if (!code)
- size = 0;
- } else if (*src <= 0xbf) {
- /* Illegal code */
- code = '?';
- } else if (*src <= 0xdf) {
- code = *src++ & 0x1f;
- extension_bytes = 1;
- } else if (*src <= 0xef) {
- code = *src++ & 0x0f;
- extension_bytes = 2;
- } else if (*src <= 0xf7) {
- code = *src++ & 0x07;
- extension_bytes = 3;
- } else {
- /* Illegal code */
- code = '?';
- }
- for (; extension_bytes && size; --size, --extension_bytes) {
- if ((*src & 0xc0) == 0x80) {
- code <<= 6;
- code |= *src++ & 0x3f;
- } else {
- /* Illegal code */
- code = '?';
- ++src;
- --size;
- break;
- }
- }
- if (code < 0x10000) {
- *dest++ = code;
- } else {
- /*
- * Simplified expression for
- * (((code - 0x10000) >> 10) & 0x3ff) | 0xd800
- */
- *dest++ = (code >> 10) + 0xd7c0;
- *dest++ = (code & 0x3ff) | 0xdc00;
- }
- }
- return dest;
- }
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