/*
* Copyright © 2012 Intel Corporation
* Copyright © 2014 Ran Benita <ran234@gmail.com>
* SPDX-License-Identifier: MIT
*
* Author: Rob Bradford <rob@linux.intel.com>
*/
#include "config.h"
#include "utils.h"
#include "utf8.h"
/* Conformant encoding form conversion from UTF-32 to UTF-8.
*
* See https://www.unicode.org/versions/Unicode15.0.0/ch03.pdf#G28875
* for further details.
*/
int
utf32_to_utf8(uint32_t unichar, char *buffer)
{
int count, shift, length;
uint8_t head;
/* NOLINTBEGIN(bugprone-branch-clone) */
if (unichar <= 0x007f) {
buffer[0] = (char) unichar;
buffer[1] = '\0';
return 2;
}
else if (unichar <= 0x07FF) {
length = 2;
head = 0xc0;
}
/* Handle surrogates */
else if (0xd800 <= unichar && unichar <= 0xdfff) {
goto ill_formed_code_unit_subsequence;
}
else if (unichar <= 0xffff) {
length = 3;
head = 0xe0;
}
else if (unichar <= 0x10ffff) {
length = 4;
head = 0xf0;
}
else {
goto ill_formed_code_unit_subsequence;
}
/* NOLINTEND(bugprone-branch-clone) */
for (count = length - 1, shift = 0; count > 0; count--, shift += 6)
buffer[count] = (char)(0x80 | ((unichar >> shift) & 0x3f));
buffer[0] = (char)(head | ((unichar >> shift) & 0x3f));
buffer[length] = '\0';
return length + 1;
ill_formed_code_unit_subsequence:
buffer[0] = '\0';
return 0;
}
bool
is_valid_utf8(const char *ss, size_t len)
{
size_t i = 0;
size_t tail_bytes = 0;
const uint8_t *s = (const uint8_t *) ss;
/* This beauty is from:
* The Unicode Standard Version 6.2 - Core Specification, Table 3.7
* https://www.unicode.org/versions/Unicode6.2.0/ch03.pdf#G7404
* We can optimize if needed. */
while (i < len)
{
/* NOLINTBEGIN(bugprone-branch-clone) */
if (s[i] <= 0x7F) {
tail_bytes = 0;
}
else if (s[i] >= 0xC2 && s[i] <= 0xDF) {
tail_bytes = 1;
}
else if (s[i] == 0xE0) {
i++;
if (i >= len || !(s[i] >= 0xA0 && s[i] <= 0xBF))
return false;
tail_bytes = 1;
}
else if (s[i] >= 0xE1 && s[i] <= 0xEC) {
tail_bytes = 2;
}
else if (s[i] == 0xED) {
i++;
if (i >= len || !(s[i] >= 0x80 && s[i] <= 0x9F))
return false;
tail_bytes = 1;
}
else if (s[i] >= 0xEE && s[i] <= 0xEF) {
tail_bytes = 2;
}
else if (s[i] == 0xF0) {
i++;
if (i >= len || !(s[i] >= 0x90 && s[i] <= 0xBF))
return false;
tail_bytes = 2;
}
else if (s[i] >= 0xF1 && s[i] <= 0xF3) {
tail_bytes = 3;
}
else if (s[i] == 0xF4) {
i++;
if (i >= len || !(s[i] >= 0x80 && s[i] <= 0x8F))
return false;
tail_bytes = 2;
}
else {
return false;
}
/* NOLINTEND(bugprone-branch-clone) */
i++;
while (i < len && tail_bytes > 0 && s[i] >= 0x80 && s[i] <= 0xBF) {
i++;
tail_bytes--;
}
if (tail_bytes != 0)
return false;
}
return true;
}
