/*-
 * Copyright (c) 1999, 2000, 2001, 2002, 2003 Lev Walkin <vlm@lionet.info>.
 * 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.
 *
 * $Id: urlenc.c,v 1.3 2005/05/25 21:55:10 vlm Exp $
 */

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

#ifdef	HAVE_CONFIG_H
#include "config.h"
#endif

#include <sf_cgi.h>
#include <sf_mem.h>
#include <sf_smisc.h>

/*
 * Static pointers to encode and decode buffers.
 */
static char *_sf_urld_buf = NULL;
static ssize_t _sf_urld_buflen = 0;
static char *_sf_urle_buf = NULL;
static int _sf_urle_buflen = 0;

char *
url_decode(const char *str) {
	char *buf;
	char *p;
	int n;
	unsigned char c;

	n = (str ? strlen(str) : 0) + 1;
	if(n < _sf_urld_buflen)
		n = _sf_urld_buflen;

	p = buf = (char *)sf_malloc(n);
	if(p == NULL)
		return NULL;

	/*
	 * If string is NULL, then return empty string.
	 */
	if(str == NULL) {
		if(_sf_urld_buf)
			free(_sf_urld_buf);
		_sf_urld_buflen = n;
		*p = '\0';
		return (_sf_urld_buf = buf);
	}

	for((void)p; (c = *str); str++, p++) {
		if(c == '%') {
			char a, b;

			if( !(a = str[1]) || !(b = str[2]) ) {
				/* Incomplete, but valid */
				*p = '%';
				continue;
			}

			if(a >= 'a') a -= 32;
			if(b >= 'a') b -= 32;

			if(a >= '0' && a <= '9')
				c = a - '0';
			else if( a >= 'A' && a <= 'F')
				c = 10 + a - 'A';
			else {
				/* Strange, but valid */
				*p = '%';
				continue;
			}

			c *= 16;

			if(b >= '0' && b <= '9')
				c += b - '0';
			else if( b >= 'A' && b <= 'F')
				c += 10 + b - 'A';
			else {
				*p = '%';
				/* Strange, but valid */
				continue;
			}

			str+= 2;

		} else if(c == '+') {
			*p = ' ';
			continue;
		}

		*p = c;
	}


	*p = '\0';

	if(_sf_urld_buf)
		free(_sf_urld_buf);
	_sf_urld_buflen = n;
	return (_sf_urld_buf = buf);
}

char *
url_encode(const char *str) {
	char *buf;
	char *p;
	static char *table="0123456789ABCDEF";
	int n;
	unsigned char c;

	n = strlen(str?str:"") + 1;
	if(_sf_urle_buflen > n)
		n = _sf_urle_buflen;

	p = buf = (char *)sf_malloc((n + 2) * 3);
	if(p == NULL)
		/* ENOMEM? */
		return NULL;

	if(str) {
		for(; (c=*str); str++) {
			if(
				(c >= 'A' && c <= 'Z') ||
				(c >= 'a' && c <= 'z') ||
				(c >= '0' && c <= '9') ||
				strchr("@._", *str)
			) {
				*p++ = *str;
				continue;
			}
			if(c == ' ') {
				*p++ = '+';
				continue;
			}
			*p++ = '%';
			*p++ = table[ (unsigned char)(c & 0xF0) >> 4];
			*p++ = table[ (unsigned char)(c & 0x0F) ];
		} /* for */
	} /* if(str) */

	*p = '\0';

	if(_sf_urle_buf)
		free(_sf_urle_buf);
	_sf_urle_buflen = n;
	return (_sf_urle_buf = buf);
}