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/***************************************************************************
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
* This program is distributed in the hope that it will be useful, *
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
* GNU General Public License for more details. *
***************************************************************************/
/* this file contains various functionality useful to standalone systems */
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <stdio.h>
#include <string.h>
#include "unicode.h"
int utf8_to_text(const uint8_t *utf_8, char* buf, size_t buflen)
{
size_t i;
if (buflen < 1)
return -1;
if (!utf_8) {
buf[0] = '\0';
return 0;
}
size_t n = 0;
char *s = buf;
for (i = 0; utf_8[i] && n < (buflen - 1); ++i) {
if (isprint(utf_8[i])) {
*s++ = utf_8[i];
n++;
} else {
int n_chars = snprintf(s, buflen - 1 - (s - buf), "\\x%02x",
(unsigned char)utf_8[i]);
s += n_chars;
n += n_chars;
}
}
*s++ = '\0';
return n;
}
/*
* Unicode conversion functions. Conversion function inspired by
* http://stackoverflow.com/questions/23919515/how-to-convert-from-utf-16-to-utf-32-on-linux-with-std-library
* utf16le first converted to utf-32 and then back to utf-8
*/
static int is_surrogate(uint16_t uc)
{
return uc >= 0xd800 && uc <= 0xdfff;
}
static int is_high_surrogate(uint16_t uc)
{
return (uc & 0xfffffc00) == 0xd800;
}
static int is_low_surrogate(uint16_t uc)
{
return (uc & 0xfffffc00) == 0xdc00;
}
static uint32_t surrogate_to_utf32(uint16_t high, uint16_t low)
{
return (high << 10) + low - 0x35fdc00;
}
static int convert_utf16le_to_utf32(const uint8_t *input, size_t input_size,
uint32_t *output, size_t output_size)
{
const uint8_t *const end = input + input_size;
int n_output = 0;
while (input < end) {
/* Ensure at least 2 bytes are available to make up utf-16 input */
if (input+1 >= end)
return -1;
uint16_t uc = *input++;
uc |= *input++ << 8;
if (!is_surrogate(uc)) {
if ((size_t)n_output >= output_size)
return -1;
*output++ = uc;
++n_output;
} else {
if (is_high_surrogate(uc) && input < end && is_low_surrogate(*input)) {
if ((size_t)n_output >= output_size)
return -1;
*output++ = surrogate_to_utf32(uc, *input++);
++n_output;
} else {
/* Error */
return -1;
}
}
}
return n_output;
}
int utf16le_to_utf8(const uint8_t *utf_16le, size_t len, uint8_t* buf, size_t buflen)
{
uint32_t utf32[256];
uint8_t *p = buf;
uint8_t *endbuf = p + buflen;
int n_code_points;
int i;
if (len < 1)
return -1;
n_code_points = convert_utf16le_to_utf32(utf_16le, len,
&utf32[0], sizeof(utf32)/sizeof(utf32[0]));
/* Invalid input is returned as a null string. */
if (n_code_points < 0)
return -1;
for (i = 0; i < n_code_points; ++i) {
uint32_t uc = utf32[i];
uint8_t utf8_uc[6];
size_t n_utf8_uc = 0;
if (uc <= 0x7f) {
utf8_uc[0] = uc;
n_utf8_uc = 1;
} else if (uc <= 0x7ff) {
utf8_uc[0] = 0xc0 | ((uc >> 6) & 0x1f);
utf8_uc[1] = 0x80 | (uc & 0x3f);
n_utf8_uc = 2;
} else if (uc <= 0xffff) {
utf8_uc[0] = 0x70 | ((uc >> 12) & 0x0f);
utf8_uc[1] = 0x80 | ((uc >> 6) & 0x3f);
utf8_uc[2] = 0x80 | (uc & 0x3f);
n_utf8_uc = 3;
} else if (uc <= 0x1fffff) {
utf8_uc[0] = 0xf0 | ((uc >> 18) & 0x07);
utf8_uc[1] = 0x80 | ((uc >> 12) & 0x3f);
utf8_uc[2] = 0x80 | ((uc >> 6) & 0x3f);
utf8_uc[3] = 0x80 | (uc & 0x3f);
n_utf8_uc = 4;
} else if (uc <= 0x3ffffff) {
utf8_uc[0] = 0xf8 | ((uc >> 24) & 0x03);
utf8_uc[1] = 0x80 | ((uc >> 18) & 0x3f);
utf8_uc[2] = 0x80 | ((uc >> 12) & 0x3f);
utf8_uc[3] = 0x80 | ((uc >> 6) & 0x3f);
utf8_uc[4] = 0x80 | (uc & 0x3f);
n_utf8_uc = 5;
} else if (uc <= 0x7fffffff) {
utf8_uc[0] = 0xfc | ((uc >> 30) & 0x01);
utf8_uc[1] = 0x80 | ((uc >> 24) & 0x3f);
utf8_uc[2] = 0x80 | ((uc >> 18) & 0x3f);
utf8_uc[3] = 0x80 | ((uc >> 12) & 0x3f);
utf8_uc[4] = 0x80 | ((uc >> 6) & 0x3f);
utf8_uc[5] = 0x80 | (uc & 0x3f);
n_utf8_uc = 6;
} else {
/* Invalid utf-32 value. */
return -1;
}
/* Out of space in output buffer? */
if (p + n_utf8_uc + 1 >= endbuf)
return -1;
memcpy(p, utf8_uc, n_utf8_uc);
p += n_utf8_uc;
}
*p = '\0';
return p - buf;
}