Hash :
40aab05e
Author :
Date :
2019-12-27T13:03:20
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/*
* Copyright © 2012 Intel Corporation
* Copyright © 2014 Ran Benita <ran234@gmail.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*
* Author: Rob Bradford <rob@linux.intel.com>
*/
#include "config.h"
#include <stddef.h>
#include <stdbool.h>
#include <inttypes.h>
#include "utf8.h"
int
utf32_to_utf8(uint32_t unichar, char *buffer)
{
int count, shift, length;
uint8_t head;
if (unichar <= 0x007f) {
buffer[0] = unichar;
buffer[1] = '\0';
return 2;
}
else if (unichar <= 0x07FF) {
length = 2;
head = 0xc0;
}
else if (unichar <= 0xffff) {
length = 3;
head = 0xe0;
}
else if (unichar <= 0x10ffff) {
length = 4;
head = 0xf0;
}
else {
buffer[0] = '\0';
return 0;
}
for (count = length - 1, shift = 0; count > 0; count--, shift += 6)
buffer[count] = 0x80 | ((unichar >> shift) & 0x3f);
buffer[0] = head | ((unichar >> shift) & 0x3f);
buffer[length] = '\0';
return length + 1;
}
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)
{
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;
}
i++;
while (i < len && tail_bytes > 0 && s[i] >= 0x80 && s[i] <= 0xBF) {
i++;
tail_bytes--;
}
if (tail_bytes != 0)
return false;
}
return true;
}