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/**
* mds — A micro-display server
* Copyright © 2014 Mattias Andrée (maandree@member.fsf.org)
*
* 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 3 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.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "string.h"
#include <libmdsserver/macros.h>
#include <stdlib.h>
/**
* Get the length of a string.
*
* @param string The string.
* @return The length of the string.
*/
size_t string_length(const char32_t* restrict string)
{
size_t i = 0;
while (string[i] >= 0)
i++;
return i;
}
/**
* Convert a NUL-terminated UTF-8 string to a -1-terminated UTF-32 string.
*
* @param string The UTF-8 string.
* @return The string in UTF-32, `NULL` on error.
*/
char32_t* string_decode(const char* restrict string)
{
size_t i, j, n, length = 0;
char32_t* rc;
/* Get the length of the UTF-32 string, excluding termination. */
for (i = 0; string[i]; i++)
if ((string[i] & 0xC0) != 0x80)
length++;
/* Allocated UTF-32 string. */
if (xmalloc(rc, length + 1, char32_t))
return NULL;
/* Convert to UTF-32. */
for (i = j = n = 0; string[i]; i++)
{
char c = string[i];
if (n)
{
rc[j] <<= 6, rc[j] |= c & 0x3F;
if (--n == 0)
j++;
}
else if ((c & 0xC0) == 0xC0)
{
while (c & 0x80)
n++, c = (char)(c << 1);
rc[j] = c >> n--;
}
else
rc[j++] = c & 255;
}
/* -1-terminate and return. */
return rc[length] = -1, rc;
}
/**
* Convert a -1-terminated UTF-32 string to a NUL-terminated Modified UTF-8 string.
*
* @param string The UTF-32 string.
* @return The string in UTF-8, `NULL` on error.
*/
char* string_encode(const char32_t* restrict string)
{
size_t i, j, n = string_length(string);
char* restrict rc;
/* Allocated Modified UTF-8 string. */
if (xmalloc(rc, 6 * n + 1, char))
return NULL;
/* Convert to Modified UTF-8. */
for (i = j = 0; i < n; i++)
{
#define _c(s) rc[j++] = (char)(((c >> (s)) & 0x3F) | 0x80)
#define _t(s) c < (char32_t)(1L << s)
char32_t c = string[i];
if (c == 0) rc[j++] = (char)0xC0, rc[j++] = (char)0x80;
else if (_t( 7)) rc[j++] = (char)c;
else if (_t(11)) rc[j++] = (char)((c >> 6) | 0xC0), _c( 0);
else if (_t(16)) rc[j++] = (char)((c >> 12) | 0xE0), _c( 6), _c( 0);
else if (_t(21)) rc[j++] = (char)((c >> 18) | 0xF0), _c(12), _c( 6), _c( 0);
else if (_t(26)) rc[j++] = (char)((c >> 24) | 0xF8), _c(18), _c(12), _c( 6), _c(0);
else rc[j++] = (char)((c >> 30) | 0xFC), _c(24), _c(18), _c(12), _c(6), _c(0);
#undef _t
#undef _c
}
/* NUL-terminate and return. */
return rc[j] = '\0', rc;
}
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