533 lines
14 KiB
C
533 lines
14 KiB
C
/* SPDX-License-Identifier: LGPL-2.1+ */
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/* Parts of this file are based on the GLIB utf8 validation functions. The
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* original license text follows. */
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/* gutf8.c - Operations on UTF-8 strings.
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*
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* Copyright (C) 1999 Tom Tromey
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* Copyright (C) 2000 Red Hat, Inc.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include <errno.h>
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#include <stdbool.h>
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#include <stdlib.h>
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#include <string.h>
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#include "alloc-util.h"
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#include "gunicode.h"
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#include "hexdecoct.h"
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#include "macro.h"
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#include "utf8.h"
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bool unichar_is_valid(char32_t ch) {
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if (ch >= 0x110000) /* End of unicode space */
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return false;
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if ((ch & 0xFFFFF800) == 0xD800) /* Reserved area for UTF-16 */
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return false;
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if ((ch >= 0xFDD0) && (ch <= 0xFDEF)) /* Reserved */
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return false;
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if ((ch & 0xFFFE) == 0xFFFE) /* BOM (Byte Order Mark) */
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return false;
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return true;
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}
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static bool unichar_is_control(char32_t ch) {
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/*
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0 to ' '-1 is the C0 range.
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DEL=0x7F, and DEL+1 to 0x9F is C1 range.
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'\t' is in C0 range, but more or less harmless and commonly used.
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*/
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return (ch < ' ' && !IN_SET(ch, '\t', '\n')) ||
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(0x7F <= ch && ch <= 0x9F);
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}
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/* count of characters used to encode one unicode char */
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static size_t utf8_encoded_expected_len(const char *str) {
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uint8_t c;
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assert(str);
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c = (uint8_t) str[0];
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if (c < 0x80)
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return 1;
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if ((c & 0xe0) == 0xc0)
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return 2;
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if ((c & 0xf0) == 0xe0)
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return 3;
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if ((c & 0xf8) == 0xf0)
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return 4;
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if ((c & 0xfc) == 0xf8)
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return 5;
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if ((c & 0xfe) == 0xfc)
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return 6;
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return 0;
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}
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/* decode one unicode char */
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int utf8_encoded_to_unichar(const char *str, char32_t *ret_unichar) {
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char32_t unichar;
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size_t len, i;
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assert(str);
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len = utf8_encoded_expected_len(str);
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switch (len) {
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case 1:
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*ret_unichar = (char32_t)str[0];
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return 0;
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case 2:
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unichar = str[0] & 0x1f;
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break;
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case 3:
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unichar = (char32_t)str[0] & 0x0f;
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break;
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case 4:
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unichar = (char32_t)str[0] & 0x07;
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break;
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case 5:
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unichar = (char32_t)str[0] & 0x03;
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break;
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case 6:
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unichar = (char32_t)str[0] & 0x01;
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break;
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default:
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return -EINVAL;
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}
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for (i = 1; i < len; i++) {
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if (((char32_t)str[i] & 0xc0) != 0x80)
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return -EINVAL;
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unichar <<= 6;
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unichar |= (char32_t)str[i] & 0x3f;
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}
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*ret_unichar = unichar;
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return 0;
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}
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bool utf8_is_printable_newline(const char* str, size_t length, bool newline) {
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const char *p;
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assert(str);
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for (p = str; length;) {
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int encoded_len, r;
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char32_t val;
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encoded_len = utf8_encoded_valid_unichar(p);
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if (encoded_len < 0 ||
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(size_t) encoded_len > length)
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return false;
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r = utf8_encoded_to_unichar(p, &val);
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if (r < 0 ||
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unichar_is_control(val) ||
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(!newline && val == '\n'))
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return false;
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length -= encoded_len;
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p += encoded_len;
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}
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return true;
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}
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char *utf8_is_valid(const char *str) {
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const char *p;
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assert(str);
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p = str;
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while (*p) {
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int len;
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len = utf8_encoded_valid_unichar(p);
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if (len < 0)
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return NULL;
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p += len;
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}
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return (char*) str;
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}
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char *utf8_escape_invalid(const char *str) {
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char *p, *s;
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assert(str);
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p = s = malloc(strlen(str) * 4 + 1);
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if (!p)
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return NULL;
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while (*str) {
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int len;
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len = utf8_encoded_valid_unichar(str);
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if (len > 0) {
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s = mempcpy(s, str, len);
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str += len;
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} else {
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s = stpcpy(s, UTF8_REPLACEMENT_CHARACTER);
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str += 1;
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}
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}
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*s = '\0';
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return p;
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}
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char *utf8_escape_non_printable(const char *str) {
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char *p, *s;
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assert(str);
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p = s = malloc(strlen(str) * 4 + 1);
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if (!p)
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return NULL;
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while (*str) {
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int len;
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len = utf8_encoded_valid_unichar(str);
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if (len > 0) {
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if (utf8_is_printable(str, len)) {
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s = mempcpy(s, str, len);
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str += len;
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} else {
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while (len > 0) {
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*(s++) = '\\';
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*(s++) = 'x';
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*(s++) = hexchar((int) *str >> 4);
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*(s++) = hexchar((int) *str);
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str += 1;
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len--;
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}
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}
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} else {
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s = stpcpy(s, UTF8_REPLACEMENT_CHARACTER);
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str += 1;
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}
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}
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*s = '\0';
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return p;
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}
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char *ascii_is_valid(const char *str) {
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const char *p;
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/* Check whether the string consists of valid ASCII bytes,
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* i.e values between 0 and 127, inclusive. */
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assert(str);
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for (p = str; *p; p++)
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if ((unsigned char) *p >= 128)
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return NULL;
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return (char*) str;
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}
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char *ascii_is_valid_n(const char *str, size_t len) {
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size_t i;
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/* Very similar to ascii_is_valid(), but checks exactly len
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* bytes and rejects any NULs in that range. */
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assert(str);
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for (i = 0; i < len; i++)
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if ((unsigned char) str[i] >= 128 || str[i] == 0)
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return NULL;
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return (char*) str;
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}
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/**
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* utf8_encode_unichar() - Encode single UCS-4 character as UTF-8
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* @out_utf8: output buffer of at least 4 bytes or NULL
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* @g: UCS-4 character to encode
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*
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* This encodes a single UCS-4 character as UTF-8 and writes it into @out_utf8.
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* The length of the character is returned. It is not zero-terminated! If the
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* output buffer is NULL, only the length is returned.
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*
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* Returns: The length in bytes that the UTF-8 representation does or would
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* occupy.
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*/
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size_t utf8_encode_unichar(char *out_utf8, char32_t g) {
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if (g < (1 << 7)) {
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if (out_utf8)
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out_utf8[0] = g & 0x7f;
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return 1;
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} else if (g < (1 << 11)) {
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if (out_utf8) {
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out_utf8[0] = 0xc0 | ((g >> 6) & 0x1f);
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out_utf8[1] = 0x80 | (g & 0x3f);
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}
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return 2;
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} else if (g < (1 << 16)) {
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if (out_utf8) {
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out_utf8[0] = 0xe0 | ((g >> 12) & 0x0f);
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out_utf8[1] = 0x80 | ((g >> 6) & 0x3f);
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out_utf8[2] = 0x80 | (g & 0x3f);
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}
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return 3;
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} else if (g < (1 << 21)) {
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if (out_utf8) {
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out_utf8[0] = 0xf0 | ((g >> 18) & 0x07);
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out_utf8[1] = 0x80 | ((g >> 12) & 0x3f);
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out_utf8[2] = 0x80 | ((g >> 6) & 0x3f);
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out_utf8[3] = 0x80 | (g & 0x3f);
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}
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return 4;
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}
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return 0;
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}
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char *utf16_to_utf8(const char16_t *s, size_t length /* bytes! */) {
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const uint8_t *f;
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char *r, *t;
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assert(s);
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/* Input length is in bytes, i.e. the shortest possible character takes 2 bytes. Each unicode character may
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* take up to 4 bytes in UTF-8. Let's also account for a trailing NUL byte. */
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if (length * 2 < length)
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return NULL; /* overflow */
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r = new(char, length * 2 + 1);
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if (!r)
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return NULL;
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f = (const uint8_t*) s;
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t = r;
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while (f + 1 < (const uint8_t*) s + length) {
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char16_t w1, w2;
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/* see RFC 2781 section 2.2 */
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w1 = f[1] << 8 | f[0];
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f += 2;
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if (!utf16_is_surrogate(w1)) {
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t += utf8_encode_unichar(t, w1);
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continue;
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}
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if (utf16_is_trailing_surrogate(w1))
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continue; /* spurious trailing surrogate, ignore */
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if (f + 1 >= (const uint8_t*) s + length)
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break;
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w2 = f[1] << 8 | f[0];
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f += 2;
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if (!utf16_is_trailing_surrogate(w2)) {
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f -= 2;
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continue; /* surrogate missing its trailing surrogate, ignore */
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}
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t += utf8_encode_unichar(t, utf16_surrogate_pair_to_unichar(w1, w2));
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}
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*t = 0;
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return r;
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}
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size_t utf16_encode_unichar(char16_t *out, char32_t c) {
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/* Note that this encodes as little-endian. */
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switch (c) {
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case 0 ... 0xd7ffU:
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case 0xe000U ... 0xffffU:
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out[0] = htole16(c);
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return 1;
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case 0x10000U ... 0x10ffffU:
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c -= 0x10000U;
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out[0] = htole16((c >> 10) + 0xd800U);
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out[1] = htole16((c & 0x3ffU) + 0xdc00U);
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return 2;
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default: /* A surrogate (invalid) */
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return 0;
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}
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}
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char16_t *utf8_to_utf16(const char *s, size_t length) {
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char16_t *n, *p;
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size_t i;
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int r;
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assert(s);
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n = new(char16_t, length + 1);
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if (!n)
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return NULL;
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p = n;
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for (i = 0; i < length;) {
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char32_t unichar;
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size_t e;
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e = utf8_encoded_expected_len(s + i);
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if (e <= 1) /* Invalid and single byte characters are copied as they are */
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goto copy;
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if (i + e > length) /* sequence longer than input buffer, then copy as-is */
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goto copy;
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r = utf8_encoded_to_unichar(s + i, &unichar);
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if (r < 0) /* sequence invalid, then copy as-is */
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goto copy;
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p += utf16_encode_unichar(p, unichar);
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i += e;
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continue;
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copy:
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*(p++) = htole16(s[i++]);
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}
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*p = 0;
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return n;
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}
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size_t char16_strlen(const char16_t *s) {
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size_t n = 0;
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assert(s);
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while (*s != 0)
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n++, s++;
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return n;
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}
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/* expected size used to encode one unicode char */
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static int utf8_unichar_to_encoded_len(char32_t unichar) {
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if (unichar < 0x80)
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return 1;
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if (unichar < 0x800)
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return 2;
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if (unichar < 0x10000)
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return 3;
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if (unichar < 0x200000)
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return 4;
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if (unichar < 0x4000000)
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return 5;
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return 6;
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}
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/* validate one encoded unicode char and return its length */
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int utf8_encoded_valid_unichar(const char *str) {
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char32_t unichar;
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size_t len, i;
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int r;
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assert(str);
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len = utf8_encoded_expected_len(str);
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if (len == 0)
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return -EINVAL;
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/* ascii is valid */
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if (len == 1)
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return 1;
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/* check if expected encoded chars are available */
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for (i = 0; i < len; i++)
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if ((str[i] & 0x80) != 0x80)
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return -EINVAL;
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r = utf8_encoded_to_unichar(str, &unichar);
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if (r < 0)
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return r;
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/* check if encoded length matches encoded value */
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if (utf8_unichar_to_encoded_len(unichar) != (int) len)
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return -EINVAL;
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/* check if value has valid range */
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if (!unichar_is_valid(unichar))
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return -EINVAL;
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return (int) len;
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}
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size_t utf8_n_codepoints(const char *str) {
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size_t n = 0;
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/* Returns the number of UTF-8 codepoints in this string, or (size_t) -1 if the string is not valid UTF-8. */
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while (*str != 0) {
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int k;
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k = utf8_encoded_valid_unichar(str);
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if (k < 0)
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return (size_t) -1;
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str += k;
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n++;
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}
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return n;
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}
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size_t utf8_console_width(const char *str) {
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size_t n = 0;
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/* Returns the approximate width a string will take on screen when printed on a character cell
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* terminal/console. */
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while (*str != 0) {
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char32_t c;
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if (utf8_encoded_to_unichar(str, &c) < 0)
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return (size_t) -1;
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str = utf8_next_char(str);
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n += unichar_iswide(c) ? 2 : 1;
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}
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return n;
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}
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