/*
 * Copyright (c) 1999 G. Adam Stanislav
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	sput.utc-8.c v.1
 */

#include <stdio.h>

#define	bits(c)	(0x80 | ((c) & 0x3F))
#define	put(c)	*strptr++ = (c);
#define	putbits(c)	put(bits(c))
#define	finish()	*strptr = '\0'

char * sputu8(unsigned int c, char *strptr) {
	if (strptr != NULL) {
		if (c < 0x80) {
			put(c);
			finish();
		}
		else if (c < 0x800) {
			put(0xC0 | (c >>  6));
			putbits(c);
			finish();
		}
		else if (c < 0x10000) {
			put(0xE0 | (c >> 12));
			putbits(c >>  6);
			putbits(c);
			finish();
		}
		else if (c < 0x200000) {
			put(0xF0 | (c >> 18));
			putbits(c >> 12);
			putbits(c >>  6);
			putbits(c);
			finish();
		}
		else if (c < 0x400000) {
			put(0xF8 | (c >> 24));
			putbits(c >> 18);
			putbits(c >> 12);
			putbits(c >>  6);
			putbits(c);
			finish();
		}
		else if (c < 0x80000000) {
			put(0xFC | (c >> 30));
			putbits(c >> 24);
			putbits(c >> 18);
			putbits(c >> 12);
			putbits(c >>  6);
			putbits(c);
			finish();
		}
		else {	/* Not a valid Unicode "character" */
			finish();
		}
	}

	return strptr;
}