/* the Music Player Daemon (MPD)
 * (c)2003-2006 by Warren Dukes (warren.dukes@gmail.com
 * This project's homepage is: http://www.musicpd.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 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.
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include "utf8.h"

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

static char *latin1ToUtf8(char c)
{
	static unsigned char utf8[3];
	unsigned char uc = c;

	memset(utf8, 0, 3);

	if (uc < 128)
		utf8[0] = uc;
	else if (uc < 192) {
		utf8[0] = 194;
		utf8[1] = uc;
	} else {
		utf8[0] = 195;
		utf8[1] = uc - 64;
	}

	return (char *)utf8;
}

char *latin1StrToUtf8Dup(char *latin1)
{
	/* utf8 should have at most two char's per latin1 char */
	int len = strlen(latin1) * 2 + 1;
	char *ret = malloc(len);
	char *cp = ret;
	char *utf8;

	memset(ret, 0, len);

	len = 0;

	while (*latin1) {
		utf8 = latin1ToUtf8(*latin1);
		while (*utf8) {
			*(cp++) = *(utf8++);
			len++;
		}
		latin1++;
	}

	return realloc(ret, len + 1);
}

static char utf8ToLatin1(char *inUtf8)
{
	unsigned char c = 0;
	unsigned char *utf8 = (unsigned char *)inUtf8;

	if (utf8[0] < 128)
		return utf8[0];
	else if (utf8[0] == 195)
		c += 64;
	else if (utf8[0] != 194)
		return '?';
	return (char)(c + utf8[1]);
}

static int validateUtf8Char(char *inUtf8Char)
{
	unsigned char *utf8Char = (unsigned char *)inUtf8Char;

	if (utf8Char[0] < 0x80)
		return 1;

	if (utf8Char[0] >= 0xC0 && utf8Char[0] <= 0xFD) {
		int count = 1;
		char t = 1 << 5;
		int i;
		while (count < 6 && (t & utf8Char[0])) {
			t = (t >> 1);
			count++;
		}
		if (count > 5)
			return 0;
		for (i = 1; i <= count; i++) {
			if (utf8Char[i] < 0x80 || utf8Char[i] > 0xBF)
				return 0;
		}
		return count + 1;
	} else
		return 0;
}

int validUtf8String(char *string)
{
	int ret;

	while (*string) {
		ret = validateUtf8Char(string);
		if (0 == ret)
			return 0;
		string += ret;
	}

	return 1;
}

char *utf8StrToLatin1Dup(char *utf8)
{
	/* utf8 should have at most two char's per latin1 char */
	int len = strlen(utf8) + 1;
	char *ret = malloc(len);
	char *cp = ret;
	int count;

	memset(ret, 0, len);

	len = 0;

	while (*utf8) {
		count = validateUtf8Char(utf8);
		if (!count) {
			free(ret);
			return NULL;
		}
		*(cp++) = utf8ToLatin1(utf8);
		utf8 += count;
		len++;
	}

	return realloc(ret, len + 1);
}