/* $Id: utf8.c,v 1.2 2013/06/06 21:53:06 steffen Exp $ */
/* utf8.c
 * Copyright (C) Steffen Pohle 2013 <steffen@gulpe.de>
 *
 * spOSMroute 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.
 *
 * spOSMroute 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 <stdlib.h>
#include <strings.h>
#include "system.h"
#include "utf8.h"

uint32_t u8_decode (char *str, int *charsize) {
	uint32_t chr = 0;
	int block = 0;
	uint8_t c = 0;

	/* check how many elements */
	c = *str;
	if ((c &  0x80) == 0) {
		block = 0;
		chr = c;
	}
	else if ((c & 0xE0) == 0xC0) {		// (str[0] & 111x xxxx) == 110x xxxx
		block = 1;
		chr = c & 0x1F;
	}
	else if ((c & 0xF0) == 0xE0) {		// (str[0] & 1111 xxxx) == 1110 xxxx
		block = 2;
		chr = c & 0x0F;
	}
	else if ((c & 0xF8) == 0xF0) {		// (str[0] & 1111 1xxx) == 1111 0xxx
		block = 3;
		chr = c & 0x07;
	}
	else if ((c & 0xFC) == 0xF8) {		// (str[0] & 1111 11xx) == 1111 10xx
		block = 4;
		chr = c & 0x03;
	}
	else if ((c & 0xFE) == 0xFC) {		// (str[0] & 1111 111x) == 1111 110x
		block = 5;
		chr = c & 0x01;
	}
	else {
		/* error: no valid code */
		*charsize = 0;
		return 0;
	}

	*charsize = block+1;	/* return size in bytes for utf8 char */
	str++;

	for (;block > 0; block--) {
		c = *str;
		if ((c & 0xC0) != 0X80) {
			/* error: no valid code */
			*charsize = 0;
			return 0;
		}
		chr <<= 6;
		chr |= (c & 0x3F);
		str++;
	}

	return chr;
};


/* return the size in chars not in bytes. */
int u8_strlen (char *str) {
	int cnt, i, j;
	int bytelen = strlen (str);

	for (cnt = 0, i = 0; i < bytelen;) {
		u8_decode (str+i, &j);
		cnt++;
		i += j;
	}

	return cnt;
};


void u8_strcpy (char *dest, char *src, int pos, int size);